Multilayer moire target and their method of use to measure positional deviation of semiconductor device

Abstract

To measure the misregistration in manufacturing a semiconductor device.SOLUTION: A multilayer Moire target is useful for calculating misregistration between at least first, second, and third layers formed on a semiconductor device wafer and includes at least one group of periodic structure stacks, each group including: a first stack comprising a first periodic structure (S1P1) of the first stack, the S1P1 having a S1P1 pitch along a first axis; a second stack comprising a first periodic structure (S2P1) of the second stack, the S2P1 having a S2P1 pitch along a second axis; and a third stack comprising a first periodic structure (S3P1) of the third stack, the S3P1 having a S3P1 pitch along a third axis. At least one of the stacks includes a second periodic structure having a second periodic structure pitch along at least one fourth axis parallel to the first axis and coaxial to one of the axes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates generally to measuring misregistration in the manufacture of semiconductor devices. [Background technology]

[0002] REFERENCE TO RELATED APPLICATIONS "A NEW MULTILAYER GRATING" filed on July 10, 2019 OVER GRATING OVERLAY MEASUREMENT TARGET No. 62 / 872,422, entitled "METAL SYSTEM AND METHOD FOR USE IN AN IMPROVED MODEL DESIGN," which is incorporated herein by reference. No. 6,399,633, the disclosure of which is incorporated herein by reference and priority is claimed herein.

[0003] The following patents and patent applications of the applicant which are related to the subject matter of this application: "CONTINUOUSLY VARYING OFFSET MARK AND M U.S. Patent entitled "ETHODS OF DETERMINING OVERLAY" No. 7,440,105, A US special edition entitled "DEVICE-LIKE METROLOGY TARGETS" Patent application publication number 2018 / 0188663, "NEW MULTILAYER GRATING OVEN filed on April 5, 2019 R GRATING OVERLAY MEASUREMENT TARGET DES No. 62 / 829,839, entitled "IGN"; and Application dated September 11, 2019: "IMAGING OVERLAY TARGETS I NCLUDING MOIRE ELEMENTS AND ROTATIONAL S U.S. Provisional Patent Application No. 62 / 89 entitled "YMMETRY ARRANGEMENTS" No. 8,980 are also referenced herein, the disclosures of which are incorporated herein by reference.

[0004] Various methods and systems are provided for measuring misalignment in the manufacture of semiconductor devices. It is known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 7,046,361 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides an improved method and method for measuring misalignment in the manufacture of semiconductor devices. The purpose of this invention is to provide a system for [Means for solving the problem]

[0007] Therefore, according to a preferred embodiment of the present invention, at least a first layer and a second layer A multi-layer moire target useful for calculating the misalignment between a first layer, a second layer, and a third layer is provided. and a third layer are formed on a semiconductor device wafer, the semiconductor device wafer being , defining an xy plane, the multi-layer moiré target including at least one group of periodic structure stacks; Each of the at least one group includes at least a first layer, a second layer, and a third layer. A first periodic structure (S1P1) of a first stack formed with at least one a first periodic structure stack, S1P1 having a pitch S1P1 along a first axis; formed with at least one of the first layer, the second layer, and the third layer; The second stack includes a first periodic structure (S2P1) having a second periodic structure S2P1 along a second axis. a second periodic structure stack having a 2P1 pitch, and at least a first layer, a second layer, and and a first periodic structure of a third stack formed with at least one of the third layers. a third circumferential structure (S3P1), the S3P1 having an S3P1 pitch along a third axis; and a phase stack, the first axis being the x-axis or The second and third axes are parallel to the x-y axis, and the target is imaged in the x-y plane. When the stack is rotated, the first axis is parallel to the first axis, and at least one of the first, second, and third stacks is rotated. One is parallel to the first axis when the target is imaged in the xy plane, and the second is parallel to the first axis. along at least one fourth axis that is coaxial with one of the third axes, The second periodic structure has a periodic structure pitch of .

[0008] According to a preferred embodiment of the present invention, the first layer has a first substantially planar surface parallel to the xy plane. the first layer defines a second generally planar surface parallel to the xy plane; and the third layer defines a second generally planar surface parallel to the xy plane. A third generally planar surface is defined parallel to the xy plane, and the first axis is aligned along the xz or yz plane. The xz plane or the yz plane is located in a first plane parallel to one of the xz plane and the yz plane is located in a second plane parallel to the xz plane. Together with the y-plane, they define a three-dimensional xyz coordinate system, the second axis being a second axis parallel to the first plane. the third axis is located in a third plane parallel to the first plane, and the third axis is located in at least one The fourth axis is located within each of the first plane, the second plane, and the third plane. and is parallel to a respective one of the first axis, the second axis, or the third axis.

[0009] Preferably, the first periodic structure stack includes S1P1 formed with the first layer, and and a second periodic structure (S1P2) of the first stack formed with the second layer, 1P2 is at least one coaxial lens that is coaxial with the first axis when the target is imaged in the xy plane. The second stack of periodic structures has an S1P2 pitch along a first one of the fourth axes. , S2P1 formed with the second layer, and the second star formed with the third layer. The second periodic structure (S2P2) of the frame is a periodic structure in which the target is imaged in the xy plane. along a second one of at least one fourth axis that is coaxial with the second axis, S2 The third periodic structure stack has a pitch of S3P1 formed with the first layer; and a second periodic structure (S3P2) of a third stack formed with the third layer. , S3P2 is at least one of the fourth axes when the target is imaged in the xy plane. Along a third one has an S3P2 pitch.

[0010] Preferably, the S2P1 pitch is related to the S1P2 pitch by a second stack multiplication factor. The S2P2 pitch is related to the S1P1 pitch by a second stack multiplication factor. and the S3P1 pitch is related to the S1P1 pitch by a third stack multiplication factor. The S3P2 pitch is related to the S1P2 pitch by a third stack multiplication factor. According to a preferred embodiment of the present invention, the second stack multiplication factor is equal to 1 and the first A stack multiplication factor of 3 is equal to 1.

[0011] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is along a first one of the at least one fourth axis. The second periodic structure stack has an S1P2 pitch formed with the first layer. P1, and a second periodic structure (S2P2) of the second stack formed with the second layer. and S2P2 includes an S2P2 pin along a second one of the at least one fourth axis. a third periodic structure stack having a second layer and a third periodic structure stack having a second layer and a third periodic structure stack formed with the second layer; A second periodic structure (S3P2) of a third stack formed with a third layer, S3 P2 has an S3P2 pitch along a third one of the at least one fourth axis .

[0012] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is along a first one of the at least one fourth axis. The second periodic structure stack has an S1P2 pitch formed with the first layer. P1, and a second periodic structure (S2P2) of the second stack formed with the second layer. and S2P2 includes an S2P2 pin along a second one of the at least one fourth axis. a third periodic structure stack having a second layer and a third periodic structure stack having a second layer and a third periodic structure stack formed with the second layer; A second periodic structure (S3P2) of a third stack formed with the first layer, S3 P2 has an S3P2 pitch along a third one of the at least one fourth axis .

[0013] Preferably, the S3P1 pitch is related to the S2P2 pitch by a third stack multiplication factor. and the S3P2 pitch is related to the S2P1 pitch by a third stack multiplication factor. According to a preferred embodiment of the present invention, the third stack multiplication factor is equal to 1. According to a preferred embodiment of the present invention, the S1P1 pitch is the same as the S2P2 pitch. , the S1P2 pitch is the same as the S2P1 pitch. Alternatively, the S1P1 pitch is The S1P2 pitch differs from the S1P1 pitch only in the additive term, while the S1P2 pitch is the same as the S1P1 pitch. The S2P2 pitch differs from the S1P1 pitch only in the additive term, while the S3P1 pitch is Unlike the S1P1 pitch, the S3P2 pitch is the same as the S1P1 pitch.

[0014] According to a preferred embodiment of the present invention, the first periodic structure stack is formed together with the second layer. The second periodic structure stack includes S1P1 formed with the first layer, and S2 P1, and a second periodic structure (S2P2) of the second stack formed with the second layer. and S2P2 includes an S2P2 pin along a second one of the at least one fourth axis. a third periodic structure stack having a second layer and a third periodic structure stack having a second layer and a third periodic structure stack formed with the second layer; A second periodic structure (S3P2) of a third stack formed with a third layer, S3 P2 has an S3P2 pitch along a third one of the at least one fourth axis According to a preferred embodiment of the present invention, the S2P1 pitch is the same as the S3P2 pitch. , the S2P2 pitch is the same as the S3P1 pitch.

[0015] According to a preferred embodiment of the present invention, the first periodic structure stack is formed together with the second layer. The second periodic structure stack includes S1P1 formed with the first layer, and S2 P1, the third periodic structure stack includes S3P1 formed with the second layer, and A second periodic structure (S3P2) of a third stack formed with a third layer, S3 P2 has an S3P2 pitch along at least one fourth axis.

[0016] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure stack includes S1P1 formed with the first layer, and S2 P1, the third periodic structure stack includes S3P1 formed with the first layer, and A second periodic structure (S3P2) of a third stack formed with a third layer, S3 P2 has an S3P2 pitch along at least one fourth axis.

[0017] According to a preferred embodiment of the present invention, the first periodic structure stack is formed together with the second layer. The second periodic structure stack includes S1P1 formed with the first layer, and S2 P1, the third periodic structure stack includes S3P1 formed with the second layer, and A second periodic structure (S3P2) of a third stack formed with the first layer, S3 P2 has an S3P2 pitch along at least one fourth axis.

[0018] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure stack includes S1P1 formed with the first layer, and S2 P1, and a second periodic structure (S2P2) of the second stack formed with the second layer. and S2P2 includes an S2P2 pin along a first one of the at least one fourth axis. a third periodic structure stack having a second layer and a third periodic structure stack having a second layer and a third periodic structure stack formed with the second layer; A second periodic structure (S3P2) of a third stack formed with a third layer, S3 P2 has an S3P2 pitch along a second one of the at least one fourth axis .

[0019] Preferably, at least one of the periodic structure stacks is configured such that the target is imaged in the xy plane. At least one first periodic stack group, the first axis of which is parallel to the x-axis, and the target is When imaged in the xy plane, at least one second circumferential lens has a first axis parallel to the y axis. In addition, at least one first periodic stack group and at least The second periodic stack group is identical except for the orientation.

[0020] According to a preferred embodiment of the present invention, the target is characterized by mirror image symmetry. According to a currently preferred embodiment, the target is characterized by rotational symmetry.

[0021] According to another preferred embodiment of the present invention, at least a first layer, a second layer, and a third layer A multi-layer moire target useful for calculating the misregistration between a first layer, a second layer, and a fourth layer is also provided. The second layer, the third layer, and the fourth layer are formed on a semiconductor device wafer, The device wafer defines an xy plane, and the multilayer moiré target includes at least one periodic structure stator. Each of the at least one group includes at least a first layer, a second layer, a third layer, and a first periphery of the first stack formed with at least one of the fourth layers. a first phase structure (S1P1), the S1P1 having a S1P1 pitch along a first axis; and a periodic structure stack including at least a first layer, a second layer, a third layer, and a fourth layer. A first periodic structure (S2P1) of a second stack formed with at least one of the a second periodic structure stack including: a first periodic structure stack including: a first periodic structure stack including: a first periodic structure stack including: a first periodic structure stack including: a second periodic structure stack including: , at least one of a first layer, a second layer, a third layer, and a fourth layer; a first periodic structure (S3P1) of a third stack formed together, S3P1 being a third a third periodic structure stack having an S3P1 pitch along the axis of at least the first layer; a fourth layer formed with at least one of the second layer, the third layer, and the fourth layer; A first periodic structure (S4P1) of a stack of S4P1 along a fourth axis. and a fourth periodic structure stack having a pitch, the first axis being such that the target is imaged in an xy plane. When imaged, it is parallel to either the x-axis or the y-axis, and the second, third, and fourth axes The fourth axis is parallel to the first axis when the target is imaged in the xy plane, and the fourth axis is parallel to the first axis, the second axis, At least one of the third and fourth stacks is taken when the target is imaged in the xy plane. and a first axis is parallel to the first axis and a second axis is a third axis, and a fourth axis is a fourth axis. A second periodic structure having a second pitch along at least one fifth axis that is coaxial with the first periodic structure. The periodic structure includes:

[0022] According to a preferred embodiment of the present invention, the first layer has a first substantially planar surface parallel to the xy plane. the first layer defines a second generally planar surface parallel to the xy plane; and the third layer defines a second generally planar surface parallel to the xy plane. the fourth layer defines a third generally planar surface parallel to the xy plane, and the fourth layer defines a first generally planar surface parallel to the xy plane. A first axis defines a first plane parallel to one of the xz plane or the yz plane. plane, and one of the xz plane or the yz plane, together with the xy plane, is A yz coordinate system is defined, the second axis being located in a second plane parallel to the first plane, and the third axis being is located in a third plane parallel to the first plane, and the fourth axis is located in a third plane parallel to the first plane. The at least one fifth axis is located in a plane, and the at least one fifth axis is located in a first plane, a second plane, a third plane, and a fourth plane, each of which is located within a respective one of the first axis, the second axis, the third axis, or parallel to a respective one of the fourth axes.

[0023] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The two periodic structure stacks are S2P1 formed with the first layer and S2P2 formed with the second layer. a second periodic structure (S2P2) of a second stack formed on the target; When imaged in the xy plane, at least one fifth axis that is coaxial with the second axis. The third periodic structure stack has an S2P2 pitch along the second one, and the third periodic structure stack has an S2P2 pitch along the second one along the second one. and a second period of a third stack formed with a third layer. The structure (S3P2) is a third axis when the target is imaged in the xy plane. and having an S3P2 pitch along a third one of the at least one coaxial fifth axis. The fourth periodic structure stack is S4P1 formed with the third layer, and the fourth layer is and a second periodic structure (S4P2) of a fourth stack formed together, S4P2 being a standard When the target is imaged in the xy plane, there is at least one fifth axis that is coaxial with the fourth axis. Along a fourth one of them has an S4P2 pitch.

[0024] According to a preferred embodiment of the present invention, the S3P1 pitch is multiplied by a third stack multiplication factor. The S2P2 pitch is related to the S2P2 pitch by the third stack multiplication factor. The S2P1 pitch is related to the S2P1 pitch by the fourth stack multiplication factor The S2P1 pitch is related to the S4P2 pitch by a fourth stack multiplication factor. Related to 2P2 pitch.

[0025] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The second periodic structure stack includes S2P1 formed with the second layer, and a third periodic structure The stack was formed with a second layer, S3P1, and a third layer, A second periodic structure (S3P2) of the third stack, S3P2 being arranged such that the target is When imaged, the second one of the at least one fifth axis that is coaxial with the third axis. A fourth periodic structure stack having a 3P2 pitch along the S 4P1, and a second periodic structure of the fourth stack formed with the fourth layer (S4P2 ) and S4P2 includes a small number of points that are coaxial with the fourth axis when the target is imaged in the xy plane. 4. The slits 100 have an S4P2 pitch along a third one of at least one fifth axis.

[0026] Preferably, the S4P1 pitch is related to the S3P2 pitch by a fourth stack multiplication factor. and the S4P2 pitch is related to the S3P1 pitch by a fourth stack multiplication factor. Can be attached.

[0027] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The two periodic structure stacks are S2P1 formed with the second layer, and S2P2 formed with the third layer. a second periodic structure (S2P2) of a second stack formed on the target; When imaged in the xy plane, at least one fifth axis that is coaxial with the second axis. The third periodic structure stack has an S2P2 pitch along the second one, and the third periodic structure stack is formed with the first layer. and a second period of a third stack formed with a third layer. The structure (S3P2) is a third axis when the target is imaged in the xy plane. and having an S3P2 pitch along a third one of the at least one coaxial fifth axis. The fourth periodic structure stack is S4P1 formed with the third layer, and the fourth layer is and a second periodic structure (S4P2) of a fourth stack formed together, S4P2 being a standard When the target is imaged in the xy plane, there is at least one fifth axis that is coaxial with the fourth axis. Along a fourth one of them has an S4P2 pitch.

[0028] Preferably, the S2P1 pitch is related to the S1P2 pitch by a second stack multiplication factor. The S2P2 pitch is related to the S1P1 pitch by a second stack multiplication factor. and the S3P1 pitch is related to the S1P1 pitch by a third stack multiplication factor. The S3P2 pitch is related to the S1P2 pitch by a third stack multiplication factor. and the S4P1 pitch is related to the S1P2 pitch by a fourth stack multiplication factor. The S4P2 pitch is related to the S1P1 pitch by a fourth stack multiplication factor. do.

[0029] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The second periodic structure stack includes S2P1 formed with the second layer, and a third periodic structure The stack includes a third layer formed of S3P1, and a fourth periodic structure stack is The fourth layer includes S4P1 formed with the fourth layer.

[0030] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The second periodic structure stack includes S2P1 formed with the second layer, and a third periodic structure The stack includes a S3P1 formed with a second layer, and a fourth periodic structure stack includes The fourth layer includes S4P1 formed with the fourth layer.

[0031] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The second periodic structure stack includes S2P1 formed with the second layer, and a third periodic structure The stack includes a third layer formed of S3P1, and a fourth periodic structure stack is The second layer includes S4P1 formed with the second layer.

[0032] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is coaxial with the first axis when the target is imaged in the xy plane. and a pitch S1P2 along a first one of the at least one fifth axis, The second periodic structure stack includes S2P1 formed with the second layer, and a third periodic structure The stack includes a third layer formed of S3P1, and a fourth periodic structure stack is The third layer includes S4P1 formed with the third layer.

[0033] According to a preferred embodiment of the present invention, at least one of the periodic structure stacks is At least one first circumferential lens, the first axis of which is parallel to the x-axis when imaged in the xy-plane. When the target is imaged in the xy plane, the first axis is parallel to the y axis. At least one second periodic stack group. In addition, at least one first periodic stack group. The tucks and the at least one second periodic stack are identical except for their orientation.

[0034] Preferably, the target is characterized by mirror image symmetry. According to this, the target is characterized by rotational symmetry.

[0035] According to yet another preferred embodiment of the present invention, a coating composition is provided comprising at least a first layer, a second layer, and A multi-layer moire target useful for calculating the misalignment between a third layer and a fourth layer is further provided. The first layer, the second layer, the third layer, and the fourth layer are formed on a semiconductor device wafer. the semiconductor device wafer defines an xy plane, and the multi-layer moiré target includes at least one The periodic structure stacks include a group of periodic structures, each of which includes at least a first layer, a second layer, a first stump formed with at least one of the first layer, the second layer, and the third layer; The first periodic structure (S1P1) has a pitch S1P1 along a first axis. a first periodic structure stack having at least a first layer, a second layer, a third layer, and The first periodic structure of the second stack ( a second periodic structure including a first periodic structure having a pitch S2P1 along a second axis; a structural stack and at least one of a first layer, a second layer, a third layer, and a fourth layer. a first periodic structure (S3P1) of a third stack formed with at least one of the first periodic structure (S3P1) and the second periodic structure (S3P2) of the ... a third periodic structure stack, where 3P1 has a pitch S3P1 along a third axis; The first axis is parallel to either the x-axis or the y-axis when the target is imaged in the xy plane. The second and third axes are parallel to the first axis when the target is imaged in the xy plane. At least one of the first, second, and third stacks is a target in the x-y plane. When the image is captured at , the first axis is parallel to the first axis and the second axis is a third axis. and a second periodic structure pitch along at least one fourth axis that is coaxial with one of the first and second axes. A second periodic structure is included.

[0036] According to a preferred embodiment of the present invention, the first periodic structure stack is formed with the first layer. The second periodic structure of the first stack formed with the second layer, S1P1, (S1P2), where S1P2 is along a first one of the at least one fourth axis. The second periodic structure stack has an S1P2 pitch formed with the first layer. P1, and a second periodic structure (S2P2) of the second stack formed with the third layer. and S2P2 includes an S2P2 pin along a second one of the at least one fourth axis. a third periodic structure stack having a first periodic structure stack S3P1 formed with the first layer; and A second periodic structure (S3P2) of the third stack formed with the fourth layer, S3 P2 has an S3P2 pitch along a third one of the at least one fourth axis . According to a preferred embodiment of the present invention, at least one of the periodic structure stacks is At least one first circumferential lens, the first axis of which is parallel to the x-axis when imaged in the xy-plane. When the target is imaged in the xy plane, the first axis is parallel to the y axis. At least one second periodic stack group. In addition, at least one first periodic stack group. The tucks and the at least one second periodic stack are identical except for their orientation.

[0037] The present invention will be more fully understood and appreciated from the following detailed description taken in conjunction with the drawings, in which: [Brief description of the drawings]

[0038] [Figure 1] FIG. 2 is a simplified diagram of a first embodiment of a multi-layer moire target of the present invention. [Figure 2A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 2B] 2B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 2A. [Figure 2C] 2B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 2A. [Figure 2D] 2B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 2A. [Figure 3A] 10 is a simplified flow diagram illustrating a preferred method for calculating misregistration between layers formed in the multi-layer moire target of FIG. 1 or FIGS. 2A-2D. [Figure 3B] 3B is a simplified pictorial diagram of a first embodiment of a portion of the method of FIG. 3A. [Figure 3C] 3B is a simplified pictorial diagram of a second embodiment of a portion of the method of FIG. 3A. [Figure 4] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Figure 5A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 5B] 5B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 5A. [Figure 5C] 5B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 5A. [Figure 5D] 5B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 5A. [Figure 6A] 5 is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIG. 4 or FIGS. 5A-5D. [Figure 6B] 6B is a simplified pictorial diagram of a first embodiment of a portion of the method of FIG. 6A. [Figure 6C] 6B is a simplified pictorial diagram of a second embodiment of a portion of the method of FIG. 6A. [Figure 7] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Figure 8A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 8B] 8B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 8A. [Figure 8C] 8B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 8A. [Figure 8D] 8B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD in FIG. 8A. [Figure 9A] 8 is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIG. 7 or FIGS. 8A-8D. [Figure 9B] 9B is a simplified pictorial diagram of a first and second embodiment of a portion of the method of FIG. 9A. [Figure 9C] 9B is a simplified pictorial diagram of a first and second embodiment of a portion of the method of FIG. 9A. [Figure 10]Simplified diagram of another embodiment of the multi-layer moiré target of the present invention. [Figure 11A] Simplified top view of another embodiment of the multi-layer moiré target of the present invention. [Figure 11B] Simplified first side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line B-B of FIG. 11A. [Figure 11C] Simplified second side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line C-C of FIG. 11A. [Figure 11D] Simplified third side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line D-D of FIG. 11A. [Figure 12A] Simplified flowchart showing a preferred method for calculating the misalignment between layers where the multi-layer moiré target of FIG. 10 or FIGS. 11A - 11D is formed. [Figure 12B] Simplified drawing of the first and second embodiments of a part of the method of FIG. 12A. [Figure 12C] Simplified drawing of the first and second embodiments of a part of the method of FIG. 12A. [Figure 13] Simplified diagram of another embodiment of the multi-layer moiré target of the present invention. [Figure 14A] Simplified top view of another embodiment of the multi-layer moiré target of the present invention. [Figure 14B] Simplified first side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line B-B of FIG. 14A. [Figure 14C] Simplified second side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line C-C of FIG. 14A. [Figure 14D] Simplified third side cross-sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line D-D of FIG. 14A. [Figure 15A]It is a simplified flowchart showing a preferred method for calculating the misalignment between layers where the multi-layer moiré target of FIG. 13 or FIGS. 14A to 14D is formed. [Figure 15B] It is a simplified drawing of the first and second embodiments of a part of the method of FIG. 15A. [Figure 15C] It is a simplified drawing of the first and second embodiments of a part of the method of FIG. 15A. [Figure 16] It is a simplified view of another embodiment of the multi-layer moiré target of the present invention. [Figure 17A] It is a simplified top view of another embodiment of the multi-layer moiré target of the present invention. [Figure 17B] It is a simplified first side sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line B-B of FIG. 17A. [Figure 17C] It is a simplified second side sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line C-C of FIG. 17A. [Figure 17D] It is a simplified third side sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line D-D of FIG. 17A. [Figure 18A] It is a simplified flowchart showing a preferred method for calculating the misalignment between layers where the multi-layer moiré target of FIG. 16 or FIGS. 17A to 17D is formed. [Figure 18B] It is a simplified drawing of the first embodiment of a part of the method of FIG. 18A. [Figure 18C] It is a simplified drawing of the second embodiment of a part of the method of FIG. 18A. [Figure 19A] It is a simplified top view of another embodiment of the multi-layer moiré target of the present invention. [Figure 19B] It is a simplified first side sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line B-B of FIG. 19A. [Figure 19C] It is a simplified second side sectional view of another embodiment of the multi-layer moiré target of the present invention, taken along line C-C of FIG. 19A. [Figure 19D] FIG. 19B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 19A. [Figure 20A] 1 is a simplified top view of another embodiment of a multi-layer moire target of the present invention; [Figure 20B] FIG. 20B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 20A. [Figure 20C] FIG. 20B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 20A. [Figure 20D] FIG. 20B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD in FIG. 20A. [Figure 21A] 19A-19D or 20A-20D. FIG. 20B is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIGS. [Figure 21B] 21B is a simplified pictorial diagram of a first embodiment of a portion of the method of FIG. 21A. [Figure 21C] 21B is a simplified pictorial diagram of a second embodiment of a portion of the method of FIG. 21A. [Figure 22A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 22B] FIG. 22B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 22A. [Figure 22C] FIG. 22B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 22A. [Figure 22D] FIG. 22B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 22A. [Figure 22E]FIG. 22B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 22A. [Figure 23A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 23B] FIG. 23B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 23A. [Figure 23C] FIG. 23B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 23A. [Figure 23D] FIG. 23B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 23A. [Figure 23E] FIG. 23B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 23A. [Figure 24A] 23A-23E is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIGS. 22A-22E or FIGS. 23A-23E. [Figure 24B] 23A-23E is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIGS. 22A-22E or FIGS. 23A-23E. [Figure 24C] 24C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIG. 24A and FIG. 24B. [Figure 24D] 24C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIG. 24A and FIG. 24B. [Figure 25A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 25B] FIG. 25B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 25A. [Figure 25C]FIG. 25B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 25A. [Figure 25D] FIG. 25B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 25A. [Figure 25E] FIG. 25B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 25A. [Figure 26A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 26B] FIG. 26B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 26A. [Figure 26C] FIG. 26B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 26A. [Figure 26D] FIG. 26B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD in FIG. 26A. [Figure 26E] FIG. 26B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 26A. [Figure 27A] 25A-25E or 26A-26E is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIG. 25A-25E or FIG. 26A-26E. [Figure 27B] 25A-25E or 26A-26E is a simplified flow diagram illustrating a preferred method for calculating the misregistration between layers formed in the multi-layer moire target of FIG. 25A-25E or FIG. 26A-26E. [Figure 27C] 27C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 27A and 27B. [Figure 27D] 27C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 27A and 27B. [Figure 28A]FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 28B] FIG. 28B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 28A. [Figure 28C] FIG. 28B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 28A. [Figure 28D] FIG. 28B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 28A. [Figure 28E] FIG. 28B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 28A. [Figure 29A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 29B] FIG. 29B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 29A. [Figure 29C] FIG. 29B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 29A. [Figure 29D] FIG. 29B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD of FIG. 29A. [Figure 29E] FIG. 29B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 29A. [Figure 30A] FIG. 27 is a simplified flow diagram illustrating a preferred method for calculating misregistration between layers formed with the multi-layer moire target of FIGS. 28A-28E or 29A-29E. [Figure 30B] FIG. 27 is a simplified flow diagram illustrating a preferred method for calculating misregistration between layers formed with the multi-layer moire target of FIGS. 28A-28E or 29A-29E. [Figure 30C]30C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 30A and 30B. [Figure 30D] 30C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 30A and 30B. [Figure 31A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 31B] FIG. 31B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 31A. [Figure 31C] FIG. 31B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 31A. [Figure 31D] FIG. 31B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD in FIG. 31A. [Figure 31E] FIG. 31B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 31A. [Figure 32A] FIG. 2 is a simplified top view of another embodiment of a multi-layer moire target of the present invention. [Figure 32B] FIG. 32B is a simplified first cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line BB of FIG. 32A. [Figure 32C] FIG. 32B is a simplified second cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line CC of FIG. 32A. [Fig. 32D] FIG. 32B is a simplified third cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line DD in FIG. 32A. [Figure 32E] FIG. 32B is a simplified fourth cross-sectional side view of another embodiment of a multi-layer moire target of the present invention, taken along line EE of FIG. 32A. [Figure 33A]FIG. 32 is a simplified flow diagram illustrating a preferred method for calculating misregistration between layers formed with the multi-layer moire target of FIGS. 31A-31E or 32A-32E. [Figure 33B] FIG. 32 is a simplified flow diagram illustrating a preferred method for calculating misregistration between layers formed with the multi-layer moire target of FIGS. 31A-31E or 32A-32E. [Figure 33C] 33C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 33A and 33B. [Figure 33D] 33C are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIGS. 33A and 33B. [Diagram 34] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Diagram 35] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Diagram 36] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Figure 37] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Figure 38] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. [Figure 39] FIG. 2 is a simplified diagram of another embodiment of a multi-layer moire target of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] In the following explanation, for convenience, the Hebrew equivalent of each parameter is referred to as "Hebrew letter 1", "Hebrew letter 2", "Hebrew letter 3", etc. For example, In the explanation, "Hebrew letter 1" refers to the Hebrew notation shown on the left side of equation 38. It represents: The targets and methods described herein below with reference to FIGS. 1A-39 are 1A to 39, which form part of the manufacturing process for The misregistration measured using the method involves measuring the various layers of a semiconductor device being fabricated. Used to adjust the fabrication process of semiconductor devices to more closely align them It will be understood that this can be done.

[0040] The target described later in this specification includes at least one group of periodic structure stacks, each stack It will be understood that the optical fiber includes one or more periodic structures, each of which has a pitch. In the embodiments described later in this document, all of the periodic structures within a single stack have different pitches. It will be understood that.

[0041] Reference is now made to FIG. 1, which is a simplified diagram of a first embodiment of a multi-layer moire target 100 of the present invention. FIG. 1 shows three different dimensions, indicated by the x-axis, y-axis, and z-axis. In this specification, including the original figure, these three dimensions are respectively referred to as the xy plane, the xz plane, and 1 generally shows the xy plane, and the enlarged views A, B, and C of FIG. 1 show the xz plane. Note that we show planes parallel to the surface.

[0042] The target 100 is preferably formed on a semiconductor device wafer and is preferably On the substrate wafer, at least a first layer 102, a second layer 104, and a third layer 106 are formed. Each of the first layer 102, the second layer 104, and the third layer 106 is formed in an xy plane. It will be appreciated that the first layer 102 and the second layer 10 define a substantially planar surface parallel to the surface. The fourth and third layers 106 may, but need not, be adjacent layers. Preferably, any of the first layer 102, the second layer 104, and the third layer 106 may be The material is also at least partially transparent to electromagnetic radiation. The first layer 102 is located below the second layer 104 and the third layer 106, and the third layer 10 6 is located on the first layer 102 and the second layer 104. However, the layers 102, 104 , and 106 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that.

[0043] FIG. 1 shows one possible sequence of target 100, and in other embodiments of the invention, target 10 It will be appreciated that the embodiment may include additional structures. For example, FIGS. 2A-2D and As will be described later in this specification with reference to Figures 34-39, a suitable target is the structure shown in Figure 1. It can contain multiple instances of It can be placed.

[0044] Preferably, the target 100 includes a first stack of periodic structures 122, a second stack of periodic structures 123, and a third stack of periodic structures 124. The first stack 122, the second stack 124, and the third stack 126. Each of the stacks 124 and the third stack 126 includes one or more periodic structures, and each The phase structure has a pitch. Preferably, the first stack 122, the second stack 124, and the third stack 126 do not overlap with each other.

[0045] In FIG. 1, a first stack 122, a second stack 124, and a third stack 12 Each of the six periodic structures is shown formed from a number of lines and spaces, but the present invention In another embodiment, the first stack 122, the second stack 124, and the third stack It will be appreciated that the periodic structure of the tacks 126 may be formed from any suitable periodic features. The first stack 122, the second stack 124, and the third stack 126 The periodic features forming the periodic structure contained within the It will be further understood that the first stack 122, the second stack 124, and the third stack The pitch of each of the periodic structures of the block 126 is preferably 10 nm to 3000 nm, more preferably The wavelength is preferably 200 nm to 800 nm.

[0046] A first xz plane 131 intersects with the first stack 122. A plurality of first axes 132 , located in a first xz plane 131 and parallel to the x-axis. A second xz plane 133 is located in a second A plurality of second axes 134 are located in a second xz plane 133. A third xz plane 135 intersects with the third stack 126. A third axis of numbers 136 lies in a third xz plane 135 and is parallel to the x-axis.

[0047] As can be seen particularly in the enlarged view A, the first stack 122 is formed with the first layer 102. The first stack includes a first periodic structure (S1P1) 142 formed thereon, and S1P1 142 is an S1P1 pitch designated as A along one of the first stack axes 132 The first stack 122 is a first stack formed with the second layer 104. The second periodic structure (S1P2) 144 further includes a first stump. Along another of the axes 132 is an S1P2 pitch designated as B.

[0048] S1P1 142 and S1P2 142 at least partially overlap each other and Thus, when imaging the first stack 122, a first stack moire pattern 150 is seen. It will be appreciated that the first stack may be a stack of stacked stacks, as is known in the art. Spider pattern 150 is pitch C 1 Characterized by pitch C 1 In equation 1, As shown, it is a function of pitches A and B.

number

[0049] As can be seen particularly in enlarged view B, the second stack 124 is formed with the second layer 104. The first periodic structure (S2P1) 152 of the second stack is formed. is the S2P1 pitch, specified as dB, along one of the second stack axes 134. Preferably, the S2P1 pitch dB is a second stack power designated as d. The second stack multiplication factor d is an arbitrary The second stack 124 is formed with the third layer 106. The second stack further includes a second periodic structure (S2P2) 154, 54 is designated as dA along another of the second stack axes 134. 2 pitch. Preferably, the S2P2 pitch dA is multiplied by a second stack multiplication factor d. S1P1 pitch dA is related to S1P1 pitch A. S2P2 pitch dA is related to S1P1 pitch A. The second stack multiplication factor d relates S2P1 pitch dB to S1P2 pitch B. It will be appreciated that the second stack multiplication factor d has the same value as the second stack multiplication factor d. In this case, the value of d is 1, so S2P1 pitch dB is identical to S1P2 pitch B. Therefore, the S2P2 pitch dA is equal to the S1P1 pitch A.

[0050] S2P1 152 and S2P2 154 at least partially overlap each other and Thus, when imaging the second stack 124, a second stack moire pattern 160 is seen. It will be appreciated that the second stack may be formed as known in the art. The spider pattern 160 is pitch C 2 Characterized by pitch C 2 In equation 2, As shown, the second stack is a function of multiplication factor d, pitch A, and pitch B.

number

[0051] As can be seen particularly in enlarged view C, the third stack 126 is formed with the first layer 102. The third stack includes a first periodic structure (S3P1) 162 formed thereon, and S3P1 162 1 along one of the third stack axes 136, an S3P1 pitch designated as eA. Preferably, the S3P1 pitch eA is a third stack square designated as e. The third stack multiplication factor e is an arbitrary The third stack 126 is formed with the third layer 106. The third stack further includes a second periodic structure (S3P2) 164, 64 is aligned along another of the third stack axes 136, designated as eB. Preferably, the S3P2 pitch eB is a third stack multiplication factor e Therefore, S1P2 pitch eB is related to S1P2 pitch B. The third stack multiplication factor e relates the S3P1 pitch eA to the S1P1 pitch A. It will be appreciated that the third stack multiplication factor e in the embodiment of the present invention has the same value as the third stack multiplication factor e in the embodiment of the present invention. In this state, the value of e is 1, so the S3P1 pitch eA is identical to the S1P1 pitch A. and the S3P2 pitch eB is identical to the S1P2 pitch B.

[0052] S3P1 162 and S3P2 164 at least partially overlap each other and Thus, when imaging the third stack 126, a third stack moire pattern 170 is seen. It will be appreciated that the third stack may be used as known in the art. Spider pattern 170 is pitch C 3 Characterized by pitch C 3 is expressed in Eq. 3 as As shown, the third stack is a function of a multiplication factor e, pitch A, and pitch B.

number

[0053] The misalignment between any two of the layers 102, 104, and 106 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches A, B, dA, dB, eA, and eB generate an image of the target 100. It is not necessary that the alignment be optically resolvable by the displacement measurement tool used for alignment. And pitch C 1 , C 2 , and C 3 Each of these is used to generate an image of the target 100. Preferably, the alignment is optically resolvable by the alignment measurement tool being used.

[0054] 2A-2D, which illustrate a multi-layer moire target 200 of the present invention. 2A-2D are simplified diagrams of another embodiment of the present invention. The present specification refers to these three dimensions as These are referred to as the xy plane, the xz plane, and the yz plane. FIG. 2A generally shows the xy plane, and FIG. 2C and 2D show planes parallel to the xz plane.

[0055] Target 200 is an example of an alternative arrangement of target 100 described herein above with reference to FIG. Note that additional sequences are described later in this specification with reference to Figures 34-39. The target 200 is preferably formed on a semiconductor device wafer, and is preferably a semiconductor device. At least a first layer 202, a second layer 204, and a third layer 206 are formed on the wafer. Each of the first layer 202, the second layer 204, and the third layer 206 is It will be appreciated that the first layer 202, the second layer 204, and the second layer 206 define parallel, generally planar surfaces. and third layer 206 may, but need not, be contiguous layers. Preferably, any material between the first layer 202, the second layer 204, and the third layer 206 is The embodiment shown in Figures 2A to 2D is also at least partially transparent to electromagnetic radiation. In this embodiment, the first layer 202 is located below the second layer 204 and the third layer 206, and the third layer The layer 206 is located above the first layer 202 and the second layer 204. However, the layers 202, 204 and 206 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that it is possible.

[0056] As can be particularly seen in FIG. 2A, the target 200 is divided into four target halves 212, 214, 216, and 218. In the embodiment shown in FIG. 2A, the target halves 212, 214, 216, and 218 are The rotation directions of each of the 6 and 218 in the xy plane are preferably rotated by an integer multiple of 90°. , the rotational directions in the xy plane of each of the other four target halves 212, 214, 216, and 218. In addition, the target 200 is preferably aligned in either the x-direction or the y-direction or both. According to a preferred embodiment of the present invention, When the target 200 is in the overlapping state, the entire target 200 is aligned in a single line in the x-direction. It is designed to be characterized by a single point of symmetry in the y-direction and the y-axis. However, even in such an embodiment, when in a misaligned state, the various elements of the target 200 , characterized by unique symmetric points.

[0057] Each of the target halves 212, 214, 216, and 218 includes a first periodic stack of structures. 222, a second periodic structure stack 224, and a third periodic structure stack 226. Each of the first stack 222, the second stack 224, and the third stack 226 includes: The first stack preferably includes one or more periodic structures, each periodic structure having a pitch. 222, the second stack 224, and the third stack 226 are all mutually exclusive. In FIG. 2A-FIG. 2D, the first stack 222 is connected to the second stack 224 and A third stack 226 is shown positioned closer to the center of the target 200. The third stack 226 is a stack of targets 222 and 224. 00. However, the first stack 222, the second stack The first stack 224 and the third stack 226 can be arranged at any position in the xy plane relative to each other. The electrodes can be arranged in any suitable arrangement.

[0058] In the embodiment shown in FIGS. 2A to 2D, a first stack 222, a second stack 224, and each of the periodic structures of the third stack 226 is formed from a plurality of lines and spaces. Although shown in the embodiment, in other embodiments of the present invention, the first stack 222, the second stack The periodic structure of the first stack 224 and the third stack 226 may be formed from any suitable periodic features. It will be understood that the first stack 222, the second stack 224, and The periodic features forming the periodic structure contained within the third stack 226 are formed from substructures. It will be further understood that the first stack 222, the second stack The pitch of each of the periodic structures of the first stack 224 and the second stack 226 is preferably 10 nm or less. The thickness is preferably from 200 nm to 800 nm.

[0059] As can be seen in FIG. 2A, in each of the four halves 212, 214, 216, and 218 The first stack 222 includes a first shaft 232 that intersects the first stack 222 and is located therein. A plane 231 of the second stack 224 and a plurality of second axes 23 intersect with and are located within the second stack 224. 4, and a plurality of second planes 233 intersecting the third stack 226 and located therein. A third plane 235 is defined that includes a third axis 236. , and 218, respectively, the first stack 222, the second stack 224, and the Depending on the orientation of the stack of three 226, a first plane 231, a second plane 233, and a third plane 234 may be provided. Each of the planes 235 is either an xz plane or a yz plane, and the first axis 232, the second axis The second axis 234 and the third axis 236 are parallel to the respective x-axis or y-axis. In each of the sections 212, 214, 216, and 218, a first plane 231, a second plane It will be appreciated that the surface 233, and the third plane 235 are all parallel to one another.

[0060] As can be seen particularly in FIG. 2B, the first stack 222 is formed with the first layer 202. The first stack includes a first periodic structure (S1P1) 242, the S1P1 242 being , an S1P1 pitch designated as D along one of the first stack axes 232 The first stack 222 is a first stack formed with the second layer 204. The second periodic structure (S1P2) 244 further includes a first stack Along another of the axes 232 is an S1P2 pitch designated as E.

[0061] S1P1 242 and S1P2 244 at least partially overlap each other and Thus, when imaging the first stack 222, a first stack moire pattern 250 is seen. It will be appreciated that the first stack may be a stack of stacked stacks, as is known in the art. The spider pattern 250 has a pitch of F 1 Characterized by a pitch F 1 is expressed in equation 4 as As shown, it is a function of pitches D and E.

number

[0062] As can be seen particularly in FIG. 2C, the second stack 224 is formed with the second layer 204. The first periodic structure (S2P1) 252 of the second stack is , an S2P1 pitch designated as fE along one of the second stack axes 234 Preferably, the S2P1 pitch fE is a second stack multiplication designated as f The S1P2 pitch is related to E by a factor of 0. The second stack multiplication factor f is any The second stack 224 is formed with the third layer 206. The second stack further includes a second periodic structure (S2P2) 254, 4 along another of the second stack axes 234, designated as fD. 2 pitch. Preferably, the S2P2 pitch fD is multiplied by a second stack multiplication factor f S2P2 pitch fD is related to S1P1 pitch D. The second stack multiplication factor f relates the S2P1 pitch fE to the S1P2 pitch E. It will be appreciated that the second stack multiplication factor f has the same value as the second stack multiplication factor f. In this case, the value of f is 1, so the S2P1 pitch fE is identical to the S1P2 pitch E. Therefore, the S2P2 pitch fD is equal to the S1P1 pitch D.

[0063] S2P1 252 and S2P2 254 at least partially overlap each other and Thus, when imaging the second stack 224, a second stack moire pattern 260 is seen. It will be appreciated that the second stack may be formed as known in the art. The spider pattern 260 has a pitch of F 2 Characterized by a pitch F 2 In equation 5, As shown, the second stack is a function of multiplication factor f, pitch D, and pitch E.

number

[0064] As can be seen particularly in FIG. 2D, the third stack 226 is formed with the first layer 202. The third stack includes a first periodic structure (S3P1) 262, the S3P1 262 being , an S3P1 pitch designated as gD along one of the third stack axes 236 Preferably, the S3P1 pitch gD is a third stack multiplication designated as g. The third stack multiplication factor g is related to the S1P1 pitch D by an arbitrary The third stack 226 is formed with the third layer 206. The third stack further includes a second periodic structure (S3P2) 264, 4 along another of the third stack axes 236, S3P designated as gE. 2 pitch. Preferably, the S3P2 pitch gE is multiplied by a third stack multiplication factor g. S1P2 pitch gE is related to S1P2 pitch E. The third stack multiplication factor g relates the S3P1 pitch gD to the S1P1 pitch D. It will be appreciated that the third stack multiplication factor g has the same value as the third stack multiplication factor g. In this case, the value of g is 1, so the S3P1 pitch gD is identical to the S1P1 pitch D. Therefore, the S3P2 pitch gE is identical to the S1P2 pitch E.

[0065] S3P1 262 and S3P2 264 at least partially overlap each other and Thus, when imaging the third stack 226, a third stack moire pattern 270 is seen. It will be appreciated that the third stack may be used as known in the art. The spider pattern 270 has a pitch of F 3 Characterized by a pitch F 3 is expressed in Equation 6 as As shown, the third stack is a function of multiplication factor g, pitch D, and pitch E.

number

[0066] The misalignment between any two of the layers 202, 204, and 206 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches D, E, fD, fE, gD, and gE generate an image of the target 200. It is not necessary that the alignment be optically resolvable by the displacement measurement tool used for alignment. And pitch F 1 , F 2 , and F 3 Each of these is used to generate an image of the target 200. Preferably, the alignment is optically resolvable by the alignment measurement tool being used.

[0067] Referring now to FIG. 3A, FIG. 3A illustrates a multi-layer semiconductor device formed by a target 300. The layers 102, 104, and 106 (FIG. 1), or 202, 204, and 206 of the wafer 2A-2D , a first layer 302, a second layer 304, and a third layer 306, such as In a direction parallel to either the x-direction or the y-direction, the target 100 (FIG. 1) or the target A multi-layer moire target 300, such as target 200 (FIGS. 2A-2D), may be used to calculate the misalignment. 3B and 3C are simplified flow charts showing a preferred method for 3B and 3C are respectively a first and a second embodiment of a portion of the method of FIG. 3A. 1 is a simplified pictorial diagram of

[0068] When using the target 200 (FIGS. 2A to 2D), the method described with reference to FIGS. 3A to 3C is The method is run once to calculate the displacement in either the x or y direction. It will be appreciated that the method described in FIGS. 3A-3C can be performed in a variety of ways, but typically, It is run twice to calculate the displacement in each of the x and y directions. Target 1 When using the 00 (FIG. 1), the first stack shaft 132, the second stack shaft 134, and The misalignment can be calculated only in one direction in which the third stack axis 136 and the third stack axis 136 are parallel. It will also be understood that this is possible.

[0069] As seen in the first step 307, a direction in which to measure the misalignment is selected. When using the target 100 in the manner of FIGS. 3A and 3B, the direction in which the displacement is measured is the first The stack axis 132, the second stack axis 134, and the third stack axis 136 are parallel to each other. The orientation of the target 200 is automatically selected to be the orientation of the target 200 in the manner of FIGS. 3A and 3B. When the structures of the quadrants 214 and 218 are aligned, the displacement is measured in a direction parallel to the x-axis. The structure of the quadrants 212 and 216 is used to determine the y-axis direction. It is used to measure positional deviation.

[0070] Preferably, in the next step 309, the image of the target 300 is captured with adjustable polarization, wavelength and The imaging position deviation measurement tool is generated using the imaging position deviation measurement tool having the settings of the imaging position and the numerical aperture. An example of a misalignment measurement tool is available from KLA Corp., Milpitas, California, USA. The Archer™ 700 is available from Infostalation. Pitches A, B, dA , dB, eA, eB, D, E, fD, fE, gD, and gE are used to generate the image of the target 300. It is not necessary that the alignment measurement tool be optically resolvable by the alignment measurement tool used to create the alignment measurement tool. Note, however, that pitch C 1 , C 2 , C 3 , F 1 , F 2 , and F 3 Each of is optically measured by a displacement measurement tool used to generate an image of the target 300. It is preferably degradable.

[0071] In the next step 311, a first region of interest 312 is selected, as seen in FIGS. 3B and 3C. , the second region of interest 314, and the third region of interest 316 are selected in step 307. In the quadrant, a first stack 122, a second stack 124, and a third stack 126 (FIG. 1), or a first stack 222, a second stack 224, and a third stack Each of the first stacks 322, second stacks 226 (FIGS. 2A to 2D) 3B and 3C. As seen in the illustrated embodiment, a first region of interest 312, a second region of interest 314, and and the third region of interest 316 is preferably a second region of interest located entirely within the first stack 322. As shown for one region of interest 312, each first stack 322, second stack 3, which are entirely located in each of the first and second stacks 324 and 326, respectively, but which are entirely located in the first region of interest 3 12, the second region of interest 314, and the third region of interest 316 are each a second staff For the regions of interest 314 and 316 that extend beyond the third stack 324 and the third stack 326, As shown, each of the first stack 322, the second stack 324, and the third stack It will be appreciated that the stack 326 may extend beyond the stack 326. The regions of interest 312, 314, and 316 shown are representative regions of interest and are shown in step 31 It will be further appreciated that other suitable regions of interest may also be selected at 1.

[0072] In the next step 331, as seen in Figures 3B and 3C, The location of the symmetry point 332 between all instances of the first region of interest 312 is calculated. In the next step 333, the image selected in step 311 is The location of the symmetry point 334 between all instances of the selected second region of interest 314 is calculated. In the next step 335, as seen in FIG. 3B and FIG. 3C, The location of the symmetry point 336 between all instances of the selected third region of interest 316 is calculated. will be done.

[0073] In the next step 337, the step 331 in the direction selected in step 307 is The location of the symmetry point 332 of the identified first one or more regions of interest 312 and, in step 333, The distance between the location of the symmetric point 334 of the identified second one or more regions of interest 314 is calculated. The distance found in step 337 is calculated using the gain G 1 The gain G is divided by 1 The mark For target 100, it is a function of pitch A and pitch B, as shown in Equation 7a.

number

number

[0074] In the next step 339, the step 331 in the direction selected in step 307 is The location of the symmetry point 332 of the identified first one or more regions of interest 312 and, in step 335 The distance between the location of the symmetric point 336 of the identified third one or more regions of interest 316 is calculated. The distance found in step 339 is calculated using the gain G 2 The gain G is divided by 2 The mark For target 100, it is a function of pitch A and pitch B, as shown in Equation 8a.

number

number

[0075] In the next step 341, the misalignment value reported in step 337 and the The difference between the reported misalignment value is calculated. The misalignment between the first layer 302 and the second layer 304 in a direction selected by the cap 307 In addition to the distances calculated in step 341, the method also calculates the distances to the right, left, top, It will be appreciated that the adjustment direction, such as up or down, may be further calculated. The adjustment direction is the pitch A and pitch B or pitch D and pitch E as a function of the relative values ​​of the layers 302 and 304 which one is adjusted.

[0076] Reference is now made to FIG. 4, which is a simplified diagram of another embodiment of a multi-layer moire target 400 of the present invention. FIG. 4 shows three different dimensions, indicated by the x-axis, y-axis, and z-axis. In this specification, these three dimensions are referred to as the xy plane, the xz plane, and the y 4 generally shows the xy plane, and the enlarged views A, B, and C of FIG. 4 show the xz plane. Note that the planes shown are parallel to

[0077] The target 400 is preferably formed on a semiconductor device wafer and is preferably On the substrate wafer, at least a first layer 402, a second layer 404, and a third layer 406 are provided. Each of the first layer 402, the second layer 404, and the third layer 406 is formed in the xy plane. It will be appreciated that the first layer 402 and the second layer 403 define a substantially planar surface parallel to the surface. The fourth and third layers 406 may, but need not, be adjacent layers. Preferably, any of the first layer 402, the second layer 404, and the third layer 406 may be The material is also at least partially transparent to electromagnetic radiation. In the embodiment shown in FIG. The first layer 402 is located below the second layer 404 and the third layer 406, and the third layer 40 6 is located on the first layer 402 and the second layer 404. However, the layers 402, 404 , and 406 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that.

[0078] FIG. 4 shows one possible arrangement of target 400, and in other embodiments of the invention, target 40 It will be appreciated that the embodiment may include additional structures. For example, FIGS. 5A-5D and As will be described later in this specification with reference to Figures 34-39, a suitable target is the structure shown in Figure 4. It can contain multiple instances of It can be placed.

[0079] Preferably, the target 400 includes a first stack of periodic structures 422, a second stack of periodic structures 423, and a third stack of periodic structures 424. The first stack 422, the second stack 424, and the third stack 426. Each of the stacks 424 and the third stack 426 includes one or more periodic structures, and each The phase structure has a pitch. Preferably, the first stack 422, the second stack 424, and the third stack 426 do not overlap with each other.

[0080] In FIG. 4, a first stack 422, a second stack 424, and a third stack 42 Each of the six periodic structures is shown formed from a number of lines and spaces, but the present invention In another embodiment, the first stack 422, the second stack 424, and the third stack It will be appreciated that the periodic structure of tacks 426 may be formed from any suitable periodic features. The first stack 422, the second stack 424, and the third stack 426 The periodic features forming the periodic structure contained within the It will be further understood that the first stack 422, the second stack 424, and the third stack The pitch of each of the periodic structures of the block 426 is preferably 10 nm to 3000 nm, more preferably The wavelength is preferably 200 nm to 800 nm.

[0081] A first xz plane 431 intersects with the first stack 422. A plurality of first axes 432 , located in a first xz plane 431 and parallel to the x-axis. A second xz plane 433 is located in a second A plurality of second axes 434 are located in a second xz plane 433. A third xz plane 435 intersects with the third stack 426. A third axis of numbers 436 lies in a third xz plane 435 and is parallel to the x-axis.

[0082] As can be seen particularly in the enlarged view A, the first stack 422 is formed with the first layer 402. The first stack includes a first periodic structure (S1P1) 442 formed thereon, and S1P1 442 is an S1P1 pitch designated as H along one of the first stack axes 432 The first stack 422 is a first stack formed with the second layer 404. The second periodic structure (S1P2) 444 further includes a second periodic structure (S1P2) 444 having a first stump. Along another of the axes 432 is an S1P2 pitch designated as I.

[0083] S1P1 442 and S1P2 444 at least partially overlap each other and Thus, when imaging the first stack 422, a first stack moire pattern 450 is seen. It will be appreciated that the first stack may be a stack of stacked stacks, as is known in the art. The spider pattern 450 has a pitch of J 1 It is characterized by the pitch J 1 is expressed in equation 9 as As shown, it is a function of pitch H and I.

number

[0084] As seen in close-up B, the second stack 424 is formed with the first layer 402. The first periodic structure (S2P1) 452 of the second stack is formed by: Along one of the first stack axes 434, there is an S2P1 pitch designated as K. The second stack 424 is a first stack formed with the second layer 404. The second stack axis is a second periodic structure (S2P2) 454. Along another of 434 has an S2P2 pitch designated as L.

[0085] S2P1 452 and S2P2 454 at least partially overlap each other and Thus, when imaging the second stack 424, the first stack moire pattern 460 is seen. It will be appreciated that the second stack moiré pattern 460 can be formed by stacking the pitch J 2 It is characterized by the pitch J 2 is the function of pitch K and L as shown in Equation 10. It is a number.

number

[0086] As can be seen particularly in close-up C, the third stack 426 is formed with the second layer 404. The third stack includes a first periodic structure (S3P1) 462 formed thereon, and S3P1 462 3. The S3P1 pitch designated as hL is aligned along one of the third stack axes 436. Preferably, the S3P1 pitch hL is a third stack square designated as h. The third stack multiplication factor h is related to the S2P2 pitch L by The third stack 426 is formed with the third layer 406. The third stack further includes a second periodic structure (S3P2) 464, 64 is aligned along another of the third stack axes 436, designated as hK. Preferably, the S3P2 pitch hK is multiplied by the third stack multiplication factor h. Therefore, S2P1 pitch hK is related to S2P1 pitch K. The third stack multiplication factor h relates the S3P1 pitch hL to the S2P2 pitch L. It will be appreciated that the third stack multiplication factor h in the embodiment of the present invention has the same value as the third stack multiplication factor h in the embodiment of the present invention. In this state, the value of h is 1, so the S3P1 pitch hL is identical to the S2P2 pitch L. and the S3P2 pitch hK is identical to the S2P1 pitch K.

[0087] S3P1 462 and S3P2 464 at least partially overlap each other and Thus, when imaging the third stack 426, a third stack moire pattern 470 is seen. It will be appreciated that the third stack may be used as known in the art. The spider pattern 470 is pitch J 3 It is characterized by the pitch J 3 is Equation 11 is a function of the third stack multiplication factor h, the pitch K, and the pitch L, as shown in

number

[0088] The misalignment between any two of the layers 402, 404, and 406 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches I, H, K, L, hK, and hL are used to generate an image of the target 400. It is not necessary that the optical resolution be sufficient for the misalignment measurement tool to be used. Pitch J 1 , J 2 , and J. 3 Each of the three is used to generate an image of the target 400. It is preferably optically resolvable by a misalignment metrology tool.

[0089] 5A-5D, which illustrate a multi-layer moire target 500 of the present invention. 5A-5D are simplified diagrams of another embodiment of the present invention. The present specification refers to these three dimensions as These are referred to as the xy plane and the xz plane. FIG. 5A generally shows the xy plane, and FIGS. 5B, 5C, and Note that FIG. 5A and FIG. 5D show a plane parallel to the xz plane.

[0090] Target 500 is an example of an alternative arrangement of target 400 described herein above with reference to FIG. Note that additional sequences are described later in this specification with reference to Figures 34-39. The target 500 is preferably formed on a semiconductor device wafer, and is preferably a semiconductor device. At least a first layer 502, a second layer 504, and a third layer 506 are formed on the wafer. Each of the first layer 502, the second layer 504, and the third layer 506 is It will be appreciated that the first layer 502, the second layer 504, and the second layer 506 define parallel, generally planar surfaces. and third layer 506 may, but need not, be contiguous layers. Preferably, any material between the first layer 502, the second layer 504, and the third layer 506 is The embodiment shown in Figures 5A to 5D is also at least partially transparent to electromagnetic radiation. In this embodiment, the first layer 502 is located below the second layer 504 and the third layer 506, and the third layer The layer 506 is located above the first layer 502 and the second layer 504. However, the layers 502, 504 and 506 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that it is possible.

[0091] As can be particularly seen in FIG. 5A, the target 500 is divided into four target halves 512, 514, 516, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, In the embodiment shown in FIG. 5A, the target halves 512, 514, 516, and 518 are The rotation directions of each of the 6 and 518 in the xy plane are preferably rotated by an integer multiple of 90°. , the rotational directions in the xy plane of each of the other four target halves 512, 514, 516, and 518 In addition, the target 500 is preferably aligned in either the x-direction or the y-direction or both. According to a preferred embodiment of the present invention, When the target 500 is in the overlapping state, the entire target 500 is aligned in a single line in the x-direction. It is designed to be characterized by a single point of symmetry in the y-direction and the y-axis. However, even in such an embodiment, when in a misaligned state, the various elements of the target 500 , characterized by unique symmetric points.

[0092] Each of the target halves 512, 514, 516, and 518 includes a first periodic stack of structures. 522, a second periodic structure stack 524, and a third periodic structure stack 526. Each of the first stack 522, the second stack 524, and the third stack 526 includes: The first stack preferably includes one or more periodic structures, each periodic structure having a pitch. 522, the second stack 524, and the third stack 526 are all mutually exclusive. 5A-5D, the first stack 522 is connected to the second stack 524 and A third stack 526 is shown positioned closer to the center of the target 500. The third stack 526 is a stack of targets 522 and 524 from the first stack 522 and the second stack 524. 00. However, the first stack 522, the second stack 523, The first stack 524 and the third stack 526 are actually arranged in the xy plane relative to each other. The electrodes may be arranged in any suitable arrangement relative to the substrate.

[0093] In the embodiment shown in FIGS. 5A-5D, a first stack 522, a second stack 524, and each of the periodic structures of the third stack 526 is formed of a plurality of lines and spaces. Although shown in the embodiment, in other embodiments of the present invention, the first stack 522, the second stack The periodic structure of the first stack 524 and the third stack 526 may be formed from any suitable periodic features. It will be understood that the first stack 522, the second stack 524, and The periodic features forming the periodic structure contained within the third stack 526 are formed from substructures. It will be further understood that the first stack 522, the second stack The pitch of each of the periodic structures of the third stack 524 and the third stack 526 is preferably 10 nm or less. The thickness is preferably from 200 nm to 800 nm.

[0094] As can be seen in FIG. 5A, in each of the four halves 512, 514, 516, and 518 The first stack 522 includes a first shaft 532 that intersects the first stack 522 and is located therein. A plane 531 of the second stack 524 and a plurality of second axes 53 intersect with the second stack 524 and are located therein. 4 and a second plane 533 intersecting the third stack 526 and located therein. A third plane 535 is defined that includes a third axis 536. , and 518, respectively, a first stack 522, a second stack 524, and a third stack Depending on the orientation of the stack of three 526, a first plane 531, a second plane 533, and a third plane 534 may be provided. Each of the planes 535 is either an xz plane or a yz plane, and the first axis 532, the second axis The second axis 534 and the third axis 536 are parallel to the respective x-axis or y-axis. In each of the sections 512, 514, 516, and 518, a first plane 531, a second plane It will be appreciated that the surface 533, and the third plane 535 are all parallel to one another.

[0095] As can be seen particularly in FIG. 5B, the first stack 522 is formed with the first layer 502. The first stack includes a first periodic structure (S1P1) 542, the S1P1 542 being , an S1P1 pitch designated as M along one of the first stack axes 532 The first stack 522 is a first stack formed with the second layer 504. The second periodic structure (S1P2) 544 further includes a first stack Along another of the axes 532 is an S1P2 pitch designated as N.

[0096] S1P1 542 and S1P2 544 at least partially overlap each other and Thus, when imaging the first stack 522, a first stack moire pattern 550 is seen. It will be appreciated that the first stack may be a stack of stacked stacks, as is known in the art. The spider pattern 550 is pitch O 1 Characterized by pitch O 1 is Equation 12 It is a function of pitch M and N as shown in

number

[0097] As can be seen particularly in FIG. 5C, the second stack 524 is formed with the first layer 502. The first periodic structure (S2P1) 552 of the second stack is , an S2P1 pitch designated as P along one of the second stack axes 534 The second stack 524 is a second stack formed with the second layer 504. The second stack further includes a second periodic structure (S2P2) 554. The second stack includes a second periodic structure (S2P2) 554. Along another of the axes 534 is an S1P2 pitch designated as Q.

[0098] S2P1 552 and S2P2 554 at least partially overlap each other and Thus, when imaging the second stack 524, a second stack moire pattern 560 is seen. It will be appreciated that the second stack may be formed as known in the art. The spider pattern 560 is pitch O 2 Characterized by pitch O 2 is Equation 13 is a function of pitch P and Q as shown in

number

[0099] As can be seen particularly in FIG. 5D, the third stack 526 is formed with the second layer 504. The third stack includes a first periodic structure (S3P1) 562, the S3P1 562 being , an S3P1 pitch designated as kQ along one of the third stack axes 536 Preferably, the S3P1 pitch kQ is a third stack multiplication designated as k. The third stack multiplication factor k is related to the S2P2 pitch Q by a factor The third stack 526 is formed with the third layer 506. The third stack further includes a second periodic structure (S3P2) 564, the S3P2 56 4 along another of the third stack axes 536, designated as kP 2 pitch. Preferably, the S3P2 pitch kP is determined by a third stack multiplication factor k. S2P1 pitch kP is related to S2P1 pitch P by The third stack multiplication factor k relates the S3P1 pitch kQ to the S2P2 pitch Q. It will be appreciated that the third stack multiplication factor k has the same value as the third stack multiplication factor k. In this case, the value of k is 1, so the S3P1 pitch kQ is identical to the S2P2 pitch Q. Therefore, the S3P2 pitch kP is equal to the S2P1 pitch P.

[0100] S3P1 562 and S3P2 564 at least partially overlap each other and Thus, when imaging the third stack 526, a third stack moire pattern 570 is seen. It will be appreciated that the third stack may be used as known in the art. The spider pattern 570 is pitch O 3 Characterized by pitch O 3 is Equation 14 is a function of the third stack multiplication factor k, the pitch P, and the pitch Q, as shown in

number

[0101] The misalignment between any two of the layers 502, 504, and 506 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches M, N, P, Q, kP, and kQ are used to generate an image of the target 500. It is not necessary that the optical resolution be sufficient for the misalignment measurement tool to be used. Pitch O 1 , O 2 , and O 3 Each of the three is used to generate an image of the target 500. It is preferably optically resolvable by a misalignment metrology tool.

[0102] Referring now to FIG. 6A, FIG. 6A illustrates a multi-layer semiconductor device formed by a target 600. The layers 402, 404, and 406 (FIG. 4), or 502, 504, and 506 of the wafer 6.06 (FIGS. 5A-5D) In a direction parallel to either the x-direction or the y-direction, the target 400 (FIG. 4) or the target A multi-layer moire target 600, such as target 500 (FIGS. 5A-5D), may be used to calculate the misregistration. 6B and 6C are simplified flow charts showing a preferred method for 6B and 6C are respectively a first and a second embodiment of a portion of the method of FIG. 6A. 1 is a simplified pictorial diagram of

[0103] When using the target 500 (FIGS. 5A to 5D), the method described with reference to FIGS. 6A to 6C is The method is run once to calculate the displacement in either the x or y direction. It will be appreciated that the method described in FIGS. 6A-6C can be implemented in various ways, but typically, It is run twice to calculate the displacement in each of the x and y directions. Target 4 When using the 00 (FIG. 4), the first stack shaft 432, the second stack shaft 434, and The misalignment can be calculated only in one direction in which the third stack axis 436 and the third stack axis 436 are parallel. It will also be understood that this is possible.

[0104] As seen in the first step 607, a direction in which to measure the misalignment is selected. When using the target 400 in the manner of FIGS. 6A and 6B, the direction in which the displacement is measured is the first The stack axis 432, the second stack axis 432, and the third stack axis 436 are parallel to each other. The orientation of the target 500 is automatically selected to be the orientation of the target 500 in the manner of FIGS. 6A and 6B. When the structures in the quadrants 514 and 518 are aligned, the displacement is measured in a direction parallel to the x-axis. The structures in the quadrants 512 and 516 are used to determine the y-axis It is used to measure positional deviation.

[0105] Preferably, in the next step 609, the image of the target 600 is captured with adjustable polarization, wavelength and The imaging position deviation measurement tool is generated using the imaging position deviation measurement tool having the settings of the imaging position and the numerical aperture. An example of a misalignment measurement tool is available from KLA Corp., Milpitas, California, USA. and Archer™ 700, available from Artion. Pitches I, H, L, K, hK, hL, M, N, P, Q, kP, and kQ are used to generate an image of the target 600. It is noted that the alignment measurement tool does not have to be optically resolvable by the alignment measurement tool used. However, pitch J 1 , J 2 , J 3 , O 1 , O 2 , and O 3 Each of the targets is 600 is optically resolvable by the misalignment measurement tool used to generate an image of It is preferable.

[0106] In the next step 611, a first region of interest 612 is selected, as seen in FIGS. 6B and 6C. , a second region of interest 614, and a third region of interest 616 are selected in step 607. In the quadrant, a first stack 422, a second stack 424, and a third stack 426 (FIG. 4), or the first stack 522, the second stack 524, and the third stack Each of the first stacks 622, second stacks 626, etc. (FIGS. 5A to 5D) 6B and 6C. As seen in the illustrated embodiment, a first region of interest 612, a second region of interest 614, and and the third region of interest 616 is preferably a second region of interest located entirely within the first stack 622. As shown for one region of interest 612, each first stack 622, second stack 6, but entirely located within the first region of interest 6 12, the second region of interest 614, and the third region of interest 616 are each a second staff For the regions of interest 614 and 616 that extend beyond the third stack 624 and the third stack 626 As shown, each of the first stack 622, the second stack 624, and the third stack It will be appreciated that the stack 626 may extend beyond the stack 626. The regions of interest 612, 614, and 616 shown are representative regions of interest and are shown in step 61 It will be further appreciated that other suitable regions of interest may also be selected at 1.

[0107] In the next step 631, as seen in Figures 6B and 6C, The location of the symmetry point 632 between all instances of the first region of interest 612 is calculated. In the next step 633, the image selected in step 611 is The location of the symmetry point 634 between all instances of the selected second region of interest 614 is calculated. In the next step 635, as seen in FIG. 6B and FIG. 6C, The location of the symmetry point 636 between all instances of the selected third region of interest 616 is calculated. will be done.

[0108] In the next step 637, the step 631 in the direction selected in step 607 is The location of the symmetry point 632 of the identified first one or more regions of interest 612 and, in step 633, The distance between the location of the symmetric point 634 of the identified second one or more regions of interest 614 is calculated. The distance found in step 637 is then calculated as the gain R 1 The gain is divided by R 1 The mark For target 400, it is a function of pitches H, I, K, and L, as shown in Equation 15a.

number

number

[0109] In the next step 639, the step 633 in the direction selected in step 607 is The location of the symmetry point 634 of the identified second one or more regions of interest 614 and, in step 635 The distance between the location of the symmetric point 636 of the identified third one or more regions of interest 616 is calculated. The distance found in step 639 is then calculated as the gain R 2 The gain is divided by R 2 The mark For target 400, it is a function of pitch K and pitch L, as shown in equation 16a.

number

number

[0110] In the next step 641, the misalignment value reported in step 637 and the The difference between the reported misalignment value is calculated. The misalignment between the first layer 602 and the third layer 606 in a direction selected by the cap 607 In addition to the distances calculated in step 641, the method also calculates the distances to the right, left, top, It will be appreciated that the adjustment direction, such as up or down, may be further calculated. The adjustment direction is determined by the pitch H and I and pitches K and L or pitches M and N and pitches P and Q It is a function of the relative values ​​and which of layers 602 and 606 is adjusted.

[0111] The relevant portion of the method described herein above with reference to FIGS. 6A-6C includes forming a layer 602 , 604, and 606, and the third of those layers. It will be appreciated that this may be performed prior to forming the layer. Layers 602, 604, and 606 may be formed in any suitable order relative to one another. can.

[0112] Reference is now made to FIG. 7, which is a simplified diagram of another embodiment of a multi-layer moire target 700 of the present invention. FIG. 7 shows three different dimensions, indicated by the x-axis, y-axis, and z-axis. In this specification, these three dimensions are referred to as the xy plane, the xz plane, and the y 7 generally shows the xy plane, and the enlarged views A, B, and C of FIG. 7 show the xz plane. Note that the planes shown are parallel to

[0113] The target 700 is preferably formed on a semiconductor device wafer and is preferably On the substrate wafer, at least a first layer 702, a second layer 704, and a third layer 706 are provided. Each of the first layer 702, the second layer 704, and the third layer 706 is formed in the xy plane. It will be appreciated that the first layer 702 and the second layer 703 define a substantially planar surface parallel to the surface. The fourth and third layers 706 may, but need not, be adjacent layers. Preferably, any of the first layer 702, the second layer 704, and the third layer 706 may be The material is also at least partially transparent to electromagnetic radiation. In the embodiment shown in FIG. The first layer 702 is located below the second layer 704 and the third layer 706, and the third layer 70 6 is located on the first layer 702 and the second layer 704. However, the layers 702, 704 , and 706 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that.

[0114] FIG. 7 shows one possible arrangement of target 700, and in other embodiments of the invention, target 70 It will be appreciated that the embodiment may include additional structures. For example, FIGS. 8A-8D and As will be described later in this specification with reference to Figures 34-39, a suitable target is the structure shown in Figure 7. It can contain multiple instances of It can be placed.

[0115] Preferably, the target 700 includes a first stack of periodic structures 722, a second stack of periodic structures 723, and a third stack of periodic structures 724. The first stack 722, the second stack 724, and the third stack 726. Each of the stacks 724 and the third stack 726 includes one or more periodic structures, and each The phase structure has a pitch. Preferably, the first stack 722, the second stack 724, and the third stack 726 do not overlap with each other.

[0116] In FIG. 7, a first stack 722, a second stack 724, and a third stack 72 Each of the six periodic structures is shown formed from a number of lines and spaces, but the present invention In another embodiment, the first stack 722, the second stack 724, and the third stack It will be appreciated that the periodic structure of tacks 726 may be formed from any suitable periodic features. The first stack 722, the second stack 724, and the third stack 726 The periodic features forming the periodic structure contained within the It will be further understood that the first stack 722, the second stack 724, and the third stack The pitch of each of the periodic structures of the block 726 is preferably 10 nm to 3000 nm, more preferably The wavelength is preferably 200 nm to 800 nm.

[0117] A first xz plane 731 intersects with the first stack 722. A plurality of first axes 732 , located in a first xz plane 731 and parallel to the x-axis. A second xz plane 733 is located in a second A plurality of second axes 734 are located in a second xz plane 733. A third xz plane 735 intersects with the third stack 726. A third axis of numbers 736 lies in a third xz plane 735 and is parallel to the x-axis.

[0118] As can be seen particularly in the enlarged view A, the first stack 722 is formed with the first layer 702. The first stack includes a first periodic structure (S1P1) 742 formed thereon, and S1P1 742 is an S1P1 pitch, designated as S, along one of the first stack axes 732 Preferably, the first stack 722 has , the second layer 704 or the third layer 705 which, together with S1P1 742, would produce a moire pattern. However, the first stack does not include a periodic structure formed with any of the layers 706 of the first stack. The stack 722 is a periodic structure, or a first stack 72, that is periodic along an axis parallel to the y-axis. 2. A periodic structure having a pitch size that does not produce a moiré pattern when imaging the optical fiber 100 shown in FIG. The second layer 704 does not produce a moiré pattern when imaging the first stack 722. or a periodic structure formed with the third layer 706.

[0119] As can be seen particularly in close-up B, the second stack 724 is formed with the first layer 702. The first periodic structure (S2P1) 752 of the second stack is formed. is an S2P1 pitch, designated as T, along one of the second stack axes 734. The second stack 724 is a second stack formed with the second layer 704. The second periodic structure (S2P2) 754 further includes a second stump. Along another of the axes 734 is an S2P2 pitch designated as U.

[0120] S2P1 752 and S2P2 754 at least partially overlap each other and Thus, when imaging the second stack 724, a second stack moire pattern 760 is seen. It will be appreciated that the second stack may be formed as known in the art. The spider pattern 760 is pitch V 2 Characterized by the pitch V 2 is Equation 17 It is a function of pitch T and pitch U as shown in

number

[0121] As can be seen particularly in close-up C, the third stack 726 is formed with the second layer 704. The third stack includes a first periodic structure (S3P1) 762 formed thereon, and S3P1 762 7, the S3P1 pitch designated as lU is aligned along one of the third stack axes 736. Preferably, the S3P1 pitch lU is a third stack square designated as l. The third stack multiplication factor, l, is an arbitrary The third stack 726 is formed with the third layer 706. The third stack further includes a second periodic structure (S3P2) 764, the second periodic structure being a third stack of the first periodic structure (S3P2) 764. 64 is connected to S3, designated as LT, along another of the third stack axes 736. Preferably, the S3P2 pitch is multiplied by the third stack multiplication factor l. Therefore, S1P1 pitch is related to T. S3P2 pitch is related to S2P1 pitch T. The third stack multiplication factor l relates the S3P1 pitch lU to the S2P2 pitch U. It will be appreciated that the third stack multiplication factor l in the stack 100 has the same value as the third stack multiplication factor l in the stack 100. In this state, the value of l is 1, so the S3P1 pitch lU is identical to the S2P2 pitch U. and the S3P2 pitch lT is identical to the S2P1 pitch T.

[0122] S3P1 762 and S3P2 764 at least partially overlap each other and Thus, when imaging the third stack 726, a third stack moire pattern 770 is seen. It will be appreciated that the third stack may be used as known in the art. The spider pattern 770 is pitch V 3 Characterized by the pitch V 3 is Equation 18 is a function of the third stack multiplication factor l, the pitch U, and the pitch T, as shown in

number

[0123] The misalignment between any two of the layers 702, 704, and 706 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches T, U, lU, and lT are used to generate an image of the target 700. However, the pitch S does not need to be optically resolvable by the displacement measurement tool being used. , V 2 , and V 3 Each of the three is a displacement meter used to generate an image of the target 700. Preferably, the pattern is optically resolvable by a measuring tool.

[0124] 8A-8D, which illustrate a multi-layer moire target 800 of the present invention. 8A-8D are simplified diagrams of another embodiment of the present invention. The present specification refers to these three dimensions as These are referred to as the xy plane, the xz plane, and the yz plane. FIG. 8A generally shows the xy plane, and FIG. 8C and 8D show planes parallel to the xz plane.

[0125] Target 800 is an example of an alternative arrangement of target 700 described herein above with reference to FIG. Note that additional sequences are described later in this specification with reference to Figures 34-39. The target 800 is preferably formed on a semiconductor device wafer, and is preferably a semiconductor device. At least a first layer 802, a second layer 804, and a third layer 806 are formed on the wafer. Each of the first layer 802, the second layer 804, and the third layer 806 is It will be appreciated that the first layer 802, the second layer 804, and the second layer 806 define parallel, generally planar surfaces. and third layer 806 may, but need not, be contiguous layers. Preferably, any material between the first layer 802, the second layer 804, and the third layer 806 is The embodiment shown in Figures 8A to 8D is also at least partially transparent to electromagnetic radiation. In this embodiment, the first layer 802 is located below the second layer 804 and the third layer 806, and the third layer The layer 806 is located above the first layer 802 and the second layer 804. However, the layers 802, 804 and 806 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that it is possible.

[0126] As can be particularly seen in FIG. 8A, the target 800 is divided into four target halves 812, 814, 816, 818, 819, 820, 821, 822, 823, 824, 825, 826, 827, 828, 829, 830, 831, 832, 833, 834, In the embodiment shown in FIG. 8A, the target halves 812, 814, 816, and 818 are The rotation directions of each of the 6 and 818 in the xy plane are preferably rotated by an integer multiple of 90°. , the rotational directions in the xy plane of each of the other four target halves 812, 814, 816, and 818 In addition, the target 800 is preferably aligned in either the x-direction or the y-direction or both. According to a preferred embodiment of the present invention, When the target 800 is in the overlapping state, the entire target 800 is aligned in a single line in the x-direction. It is designed to be characterized by a single point of symmetry in the y-direction and the y-axis. However, even in such an embodiment, when in a misaligned state, the various elements of the target 800 , characterized by unique symmetric points.

[0127] Each of the target halves 812, 814, 816, and 818 includes a first periodic stack of structures. 822, a second periodic structure stack 824, and a third periodic structure stack 826. Each of the first stack 822, the second stack 824, and the third stack 826 includes: The first stack preferably includes one or more periodic structures, each periodic structure having a pitch. 822, the second stack 824, and the third stack 826 are all mutually exclusive. In Figures 8A-8D, the first stack 822 is connected to the second stack 824 and A third stack 826 is shown positioned closer to the center of the target 800. The third stack 826 is a stack of targets 8 from the first stack 822 and the second stack 824. 00. However, the first stack 822, the second stack The first stack 824 and the third stack 826 can be arranged at any position in the xy plane relative to each other. The electrodes can be arranged in any suitable arrangement.

[0128] In the embodiment shown in FIGS. 8A-8D, a first stack 822, a second stack 824, and each of the periodic structures of the third stack 826 is formed of a plurality of lines and spaces. Although shown in the embodiment, in other embodiments of the present invention, the first stack 822, the second stack The periodic structure of the first stack 824 and the third stack 826 may be formed from any suitable periodic features. It will be understood that the first stack 822, the second stack 824, and The periodic features forming the periodic structure contained within the third stack 826 are formed from substructures. It will be further understood that the first stack 822, the second stack The pitch of each of the periodic structures of the third stack 824 and the third stack 826 is preferably 10 nm or less. The thickness is preferably from 200 nm to 800 nm.

[0129] As can be seen in FIG. 8A, in each of the four halves 812, 814, 816, and 818 The first stack 822 includes a first shaft 832 that intersects the first stack 822 and is located therein. A plane 831 of the second stack 824 and a plurality of second axes 83 intersect with the second stack 824 and are located therein. 4, and a plurality of second planes 833 intersecting the third stack 826 and located therein. A third plane 835 is defined that includes a third axis 836. , and 818, the first stack 822, the second stack 824, and the Depending on the orientation of the stack of three 826, a first plane 831, a second plane 833, and a third plane Each of the planes 835 is either an xz plane or a yz plane, and the first axis 832, the second axis The second axis 834 and the third axis 836 are parallel to the respective x-axis or y-axis. In each of the sections 812, 814, 816, and 818, a first plane 831, a second plane It will be appreciated that the surface 833 and the third plane 835 are all parallel to one another.

[0130] As can be seen particularly in FIG. 8B, the first stack 822 is formed with the first layer 802. The first stack includes a first periodic structure (S1P1) 842, the S1P1 842 being , an S1P1 pitch designated as W along one of the first stack axes 832 Preferably, when the first stack 822 is imaged, The second layer 804 or the third layer 805, which together with S1P1 842 would produce a moiré pattern, However, the first stack does not include a periodic structure formed with any of the layers 806 of the first stack. 822 is a periodic arrangement in a plane parallel to the xy plane along an axis perpendicular to the first stack axis 822. periodic structures that are of interest, or that produce moiré patterns when imaging the first stack 822. When imaging the first stack 822, a periodic structure having a pitch size that does not allow the The periphery formed with the second layer 804 or the third layer 806 does not produce an array pattern. It may include a period structure.

[0131] As can be seen particularly in FIG. 8C, the second stack 824 is formed with the first layer 802. The first periodic structure (S2P1) 852 of the second stack is , an S2P1 pitch designated as X along one of the second stack axes 834; The second stack 824 is a second stack formed with the second layer 804. The second stack further includes a second periodic structure (S2P2) 854. The second stack Along another of the axes 834 is an S2P2 pitch designated as Y.

[0132] S2P1 852 and S2P2 854 at least partially overlap each other and Thus, when imaging the second stack 824, a second stack moire pattern 860 is seen. It will be appreciated that the second stack may be formed as known in the art. The spider pattern 860 has a pitch of Z 2 and pitch Z 2 is Equation 19 is a function of pitch X and pitch Y as shown in

number

[0133] As can be seen particularly in FIG. 8D, the third stack 826 is formed with the second layer 804. The third stack includes a first periodic structure (S3P1) 862, the S3P1 862 being , an S3P1 pitch designated as mY along one of the third stack axes 836 Preferably, the S3P1 pitch mY is a third stack multiplication designated as m. The third stack multiplication factor m is related to the S2P2 pitch Y by a factor The third stack 826 is formed with the third layer 806. The third stack further includes a second periodic structure (S3P2) 864, the S3P2 86 4 along another of the third stack axes 836, designated as mX. 2 pitch. Preferably, the S3P2 pitch mX is multiplied by a third stack multiplication factor m. S2P1 pitch mX is related to S2P1 pitch X. The third stack multiplication factor m relates the S3P1 pitch mY to the S2P2 pitch Y. It will be appreciated that the third stack multiplication factor m has the same value as the third stack multiplication factor m. In this case, the value of m is 1, so the S3P1 pitch mY is identical to the S2P2 pitch Y. Therefore, the S3P2 pitch mX is identical to the S2P1 pitch X.

[0134] S3P1 862 and S3P2 864 at least partially overlap each other and Thus, when imaging the third stack 826, a third stack moire pattern 870 is seen. It will be appreciated that the third stack may be used as known in the art. The spider pattern 870 has a pitch of Z 3 and pitch Z 3 is Equation 20 is a function of the third stack multiplication factor m, the pitch Y, and the pitch X, as shown in

number

[0135] The misalignment between any two of the layers 802, 804, and 806 is preferably Use an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Archer™ 700 available from KLA Corporation, Texas The pitches X, Y, mY, and mX are used to generate an image of the target 800. However, the pitch W does not need to be optically resolvable by the displacement measurement tool being used. , Z 2 , and Z 3 Each of the three is a displacement meter used to generate an image of the target 800. Preferably, the pattern is optically resolvable by a measuring tool.

[0136] Referring now to FIG. 9A, FIG. 9A illustrates a multi-layer semiconductor device formed by a target 900. The wafer layers 702, 704, and 706 (FIG. 7), or 802, 804, and 8 9. A first layer 902, a second layer 904, and a third layer 906, such as 906 (FIGS. 8A-8D) In a direction parallel to either the x-direction or the y-direction, a target 700 (FIG. 7) or target A multi-layer moire target 900, such as target 800 (FIGS. 8A-8D), may be used to calculate the misalignment. 9B and 9C are simplified flow charts showing a preferred method for 9B and 9C are first and second embodiments of a portion of the method of FIG. 9A, respectively. 1 is a simplified pictorial diagram of

[0137] When using target 800 (FIGS. 8A to 8D), the method described with reference to FIGS. 9A to 9C is The method is run once to calculate the displacement in either the x or y direction. It will be appreciated that the method described in FIGS. 9A-9C can be implemented in various ways, but typically, It is run twice to calculate the displacement in each of the x and y directions. When using the 00 (FIG. 7), the first stack shaft 732, the second stack shaft 734, and The misalignment can be calculated only in one direction in which the third stack axis 736 and the third stack axis 736 are parallel. It will also be understood that this is possible.

[0138] As seen in the first step 907, a direction in which to measure the misalignment is selected. When using the target 700 in the manner of FIGS. 9A and 9B, the direction in which the displacement is measured is the first The stack axis 732, the second stack axis 734, and the third stack axis 736 are parallel to each other. The orientation of the target 800 is automatically selected to be the orientation of the target 800 in the manner of FIGS. 9A and 9B. When the structures of the quadrants 814 and 818 are aligned, the displacement is measured in a direction parallel to the x-axis. The structures in the quadrants 812 and 816 are used to determine the axial orientation of the y-axis. It is used to measure positional deviation.

[0139] Preferably, in the next step 909, the image of the target 900 is imaged with adjustable polarization, wavelength and The imaging position deviation measurement tool is generated using the imaging position deviation measurement tool having the settings of the imaging position and the numerical aperture. An example of a misalignment measurement tool is available from KLA Corp., Milpitas, California, USA. The Archer™ 700 is available from Artation. Pitches T, U, LU , lT, X, Y, mY, and mX are the coordinates used to generate an image of the target 900. Note that it is not necessary for the misalignment measurement tool to be optically resolvable. And pitch S, W, V 2 , V 3 , Z 2 , and Z 3 Each of the three generates an image of the target 900. Preferably, the alignment is optically resolvable by the alignment measurement tool used to measure alignment. .

[0140] In the next step 911, a first region of interest 912 is selected, as seen in FIGS. 9B and 9C. , a second region of interest 914, and a third region of interest 916 are selected in step 907. In the quadrant, a first stack 722, a second stack 724, and a third stack 726 (FIG. 7), or a first stack 822, a second stack 824, and a third stack Each of the first stacks 922, second stacks 826 (FIGS. 8A-8D) 9B and 9C. As seen in the illustrated embodiment, a first region of interest 912, a second region of interest 914, and and the third region of interest 916 is preferably a second region of interest located entirely within the first stack 922. As shown for one region of interest 912, each first stack 922, second stack 9, but entirely within the first region of interest 9 12, the second region of interest 914, and the third region of interest 916 are each For the regions of interest 914 and 916 that extend beyond the third stack 924 and the third stack 926, As shown, each of the first stack 922, the second stack 924, and the third stack It will be appreciated that the stack 926 may extend beyond the stack 926. The regions of interest 912, 914, and 916 shown are representative regions of interest and are shown in FIG. It will be further appreciated that other suitable regions of interest may also be selected at 1.

[0141] In the next step 931, as shown in Figures 9B and 9C, The location of the symmetry point 932 between all instances of the first region of interest 912 is calculated. In the next step 933, the image selected in step 911 is The location of the symmetry point 934 between all instances of the selected second region of interest 914 is calculated. In the next step 935, as seen in FIG. 9B and FIG. 9C, The location of the symmetry point 936 between all instances of the selected third region of interest 916 is calculated. will be done.

[0142] In the next step 937, the step 931 in the direction selected in step 907 is The location of the symmetry point 932 of the identified first one or more regions of interest 912 and, in step 933, A distance between the location of the symmetric point 934 of the identified second one or more regions of interest 914 is calculated. The distance found in step 937 is then multiplied by a gain α 1 The gain is α 1 The mark For target 700, it is a function of pitch T and pitch U, as shown in equation 21a.

number

number

[0143] In the next step 939, the step 933 in the direction selected in step 907 is The location of the symmetry point 934 of the identified second one or more regions of interest 914 and, in step 935 A distance between the location of the symmetric point 936 of the identified third one or more regions of interest 916 is calculated. The distance found in step 939 is then multiplied by a gain α 2 The gain is α 2 The mark For target 700, it is a function of pitch T and pitch U, as shown in equation 22a.

number

number

[0144] In the next step 941, the misalignment value reported in step 937 and the The difference between the reported misalignment value is calculated. The positional difference between the second layer 904 and the third layer 906 in the direction selected by the cap 907 is In addition to the distance calculated in step 941, the method also calculates the distance to the right, left, It will be appreciated that the adjustment direction, such as up or down, may also be calculated. A function of the relative values ​​of T and U or pitches X and Y, and the thickness of layers 904 and 906 The question is which of these will be adjusted.

[0145] In one embodiment of the present invention, the relevant portions of the method described herein above with reference to Figures 9A-9C are The second step uses only the first two of the layers 902, 904, and 906 to be formed. It will be appreciated that this may be performed prior to forming the third of the layers. As described herein above, layers 902, 904, and 906 may be arranged in any suitable manner relative to one another. The layers can be formed in any suitable order.

[0146] Reference is now made to FIG. 10, which illustrates another embodiment of a multi-layer moire target 1000 of the present invention. FIG. 10 is a simplified diagram of three different axes, indicated by the x-axis, y-axis, and z-axis. In this specification, these three dimensions are respectively referred to as the xy plane, the xz plane, and yz planes. FIG. 10 generally shows the xy plane, and enlarged views A, B, and C of FIG. Note that C denotes a plane parallel to the xz plane.

[0147] The target 1000 is preferably formed on a semiconductor device wafer and is preferably On the device wafer, at least a first layer 1002, a second layer 1004, and a third layer 1005 are formed. 1006 is formed. The first layer 1002, the second layer 1004, and the third layer 1006 are It will be appreciated that each defines a generally planar surface parallel to the xy plane. 2, the second layer 1004, and the third layer 1006 may be adjacent layers, This is not necessarily the case. Preferably, the first layer 1002, the second layer 1004, and the third layer Any material between the three layers 1006 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIG. 10, the first layer 1002 is made up of a second layer 1004 and a third layer 1005. 1006, the third layer 1006 is located below the first layer 1002 and the second layer 1004. However, layers 1002, 1004, and 1006 are aligned along the z axis relative to one another. It will be appreciated that the numbers may be arranged in any suitable order along the length of the filter.

[0148] Additionally, in one embodiment of the present invention, the first layer 1002 and the third layer 1006 All of the structures shown as formed can be formed with layer 1002 In such an embodiment, no portion of the target 1000 is formed with the layer 1006. Such an embodiment may be described later in this specification with reference to Figures 12A-12C. Particularly useful for proofreading.

[0149] FIG. 10 shows one possible sequence of target 1000, and in other embodiments of the invention, the target It will be appreciated that 1000 may include additional structures. For example, FIG. As will be described later in this specification with reference to Figs. 11D and 34-39, a suitable target is 0, and the multiple instances may include They can be arranged in a variety of ways.

[0150] Preferably, the target 1000 includes a first periodic structure stack 1022, a second periodic structure stack 1023, and a The first stack 1022 includes a first periodic structure stack 1024, and a third periodic structure stack 1026. Each of the first stack 1024 and the third stack 1026 includes one or more periodic structures. Preferably, the first stack 1022, the second stack 1023, and the third stack 1024 are arranged in a circular pattern. Neither stack 1024 nor the third stack 1026 overlaps with each other. .

[0151] In FIG. 10, a first stack 1022, a second stack 1024, and a third stack Each of the periodic structures in block 1026 is shown formed from a number of lines and spaces. However, in other embodiments of the present invention, the first stack 1022, the second stack 1024, and The periodic structure of the third stack 1026 may be formed from any suitable periodic features. It will be understood that the first stack 1022, the second stack 1024, and the The periodic features forming the periodic structure contained within the stack 1026 of three are formed from substructures. It will be further understood that the first stack 1022, the second stack 1023, The pitch of each of the periodic structures of the first stack 1024 and the third stack 1026 is preferably 10n The thickness is preferably from 200 nm to 3000 nm, and more preferably from 200 nm to 800 nm.

[0152] A first xz plane 1031 intersects with the first stack 1022. 32 is located in the first xz plane 1031 and is parallel to the x-axis. 3 intersects with the second stack 1024. A plurality of second axes 1034 are aligned in a second xz plane. 1033 and is parallel to the x-axis. A third xz plane 1035 is located within the third stack 1 026. A number of third axes 1036 are located in a third xz plane 1035 and It is parallel to the axis.

[0153] As can be seen particularly in the enlarged view A, the first stack 1022, together with the first layer 1002, The first stack includes a first periodic structure (S1P1) 1042 formed in the first stack, 1042 is a graph of S1, designated as β, along one of the first stack axes 1032. The first stack 1022 is formed with the second layer 1004. The first stack further includes a second periodic structure (S1P2) 1044, S1P2 104 4 is along another of the first stack axes 1032, designated as β-n. Preferably, the S1P2 pitch β-n is the first pitch designated as n. Only the first stack sum term n differs from the S1P1 pitch β. It can have any value outside of this.

[0154] S1P1 1042 and S1P2 1044 at least partially overlap each other; Thus, when imaging the first stack 1022, the first stack moire pattern 10 It will be appreciated that the first 50 can be seen. The stack moiré pattern 1050 has a pitch of γ 1 and pitch γ 1 teeth , which is a function of summation term n, pitch β, and pitch β-n, as shown in Equation 23.

number

[0155] As can be seen particularly in the enlarged view B, the second stack 1024 is formed in conjunction with the first layer 1002. The first periodic structure (S2P1) 1052 of the second stack is formed on the first periodic structure (S2P1) 1052 of the second stack. 1052 is a graph of S2, designated as β, along one of the second stack axes 1034. It is understood that the S2P1 pitch β has the same value as the S1P1 pitch β. As will be understood, the second stack 1024 is a second stack formed with the second layer 1004. The second periodic structure (S2P2) 1054 of the stack is further included, and the S2P2 1054 is a Along the other of the two stack axes 1034, the S2P2 pin, designated as β+n, Preferably, the S2P2 pitch β+n is equal to the second pitch designated as n. The second stack summation term n differs from the first stack summation term β. It will be appreciated that this has the same value as sum term n.

[0156] S2P1 1052 and S2P2 1054 at least partially overlap each other; Thus, when imaging the second stack 1024, the second stack moiré pattern 10 It will be appreciated that the second 60 can be seen as known in the art. The stack moiré pattern 1060 has a pitch of γ 2 and pitch γ 2 teeth , is a function of sum term n, pitch β, and pitch β+n, as shown in Equation 24.

number

[0157] As can be seen particularly in close-up C, the third stack 1026, together with the second layer 1004, The third stack includes a first periodic structure (S3P1) 1062 formed on the first periodic structure (S3P1) 1062. 1062 is along one of the third stack axes 1036, designated as β+n S3P1 pitch β+n has the same value as S2P2 pitch β+n It will be appreciated that the third stack 1026 is formed with the third layer 1006. The third stack further includes a second periodic structure (S3P2) 1064, 064 is aligned along another of the third stack axes 1036, designated as β. The S3P2 pitch β can have the same value as the S1P1 pitch β. Let it be understood.

[0158] S3P1 1062 and S3P2 1064 at least partially overlap each other; Thus, when imaging the third stack 1026, the third stack moiré pattern 10 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stack moiré pattern 1070 has a pitch of γ 3 and pitch γ 3 teeth , which is a function of the summation term n, the pitch β, and the pitch β+n, as shown in Equation 25.

number

[0159] The misalignment between any two of the layers 1002, 1004, and 1006 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches β, β-n, and β+n are used to generate the image of the target 1000. It is not necessary that the optical resolution be sufficient for the misalignment measurement tool to be used. Pitch γ 1 , γ 2 , and γ 3 Each of these is used to generate 1,000 images of the target. Preferably, the alignment is optically resolvable by a displacement metrology tool.

[0160] Referring now to FIGS. 11A-11D, FIGS. 11A-11D show a multi-layer moire target of the present invention. 11A-11D are simplified diagrams of another embodiment of a target 1100. , and z-axes, and these three The dimensions are referred to as the xy plane, the xz plane, and the yz plane, respectively. 11B, 11C, and 11D show planes parallel to the xz plane. I want to be loved.

[0161] Target 1100 is an example of an alternative arrangement of target 1000 described herein above with reference to FIG. and it is noted that additional sequences are described herein below with reference to Figures 34-39. The target 1100 is preferably formed on a semiconductor device wafer and is preferably a semiconductor On the device wafer, at least a first layer 1102, a second layer 1104, and a third layer The first layer 1102, the second layer 1104, and the third layer 1106 are formed. It will be appreciated that each of the first layer 11 defines a substantially planar surface parallel to the xy plane. 1102, the second layer 1104, and the third layer 1106 may be adjacent layers. , but not necessarily. Preferably, the first layer 1102, the second layer 1104, and Any material between the third layer 1106 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIGS. 11A to 11D, the first layer 1102 is and a third layer 1106, which is located below the first layer 1102 and the However, layers 1102, 1104, and 1106 are mutually It will be appreciated that the elements may be arranged in any suitable order along the z-axis relative to the object.

[0162] Additionally, in one embodiment of the present invention, the first layer 1102 and the third layer 1106, All of the structures shown as formed can be formed with layer 1102. In such an embodiment, no portion of the target 1100 is formed with the layer 1106. Such an embodiment may be described later in this specification with reference to Figures 12A-12C. Particularly useful for proofreading.

[0163] As can be particularly seen in FIG. 11A, the target 1100 is divided into four target quads 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1120, 1121, 1122, 1123, 1124, 1125, 1126, 1127, 1 11A, the target halves 111, 112, 113, 114, 115, 116, and 1118. In the embodiment shown in FIG. The rotation directions in the xy plane of each of 1112, 1114, 1116, and 1118 are preferably , the other four halves of targets 1112, 1114, 1116, and 111 are integer multiples of 90°. 8 are different from each other in the xy plane. In addition, the target 1100 is preferably It is characterized by rotational symmetry in either the x or y direction or both. According to a preferred embodiment of the invention, when target 1100 is in a superimposed state, target 1 The whole of 100 is bounded by a single point of symmetry in the x direction and a single point of symmetry in the y direction. However, even in such an embodiment, the alignment of the stator and the stator are not affected by the alignment of the stator and the stator. At times, various elements of the target 1100 are characterized by unique points of symmetry.

[0164] Each of the target halves 1112, 1114, 1116, and 1118 includes a first periodic structure. stack 1122, a second periodic structure stack 1124, and a third periodic structure stack 1 126. The first stack 1122, the second stack 1124, and the third stack Each of the blocks 1126 includes one or more periodic structures, each of which has a pitch. Generally, the first stack 1122, the second stack 1124, and the third stack 112 11A to 11D, the first stack 112 2 is the center of the target 1100 from the second stack 1124 and the third stack 1126. 11, the third stack 1126 is shown positioned adjacent to the first stack 11 22 and a second stack 1124 are shown positioned near the edge of the target 1100. However, the first stack 1122, the second stack 1124, and the third stack The stacks 1126 may be arranged in any suitable arrangement relative to each other in the xy plane. can.

[0165] In the embodiment shown in FIGS. 11A to 11D, the first stack 1122, the second stack 1 124, and the periodic structure of the third stack 1126 are each formed of a plurality of lines and spaces. Although shown in a completed state, in other embodiments of the present invention, the first stack 1122, The periodic structures of the second stack 1124 and the third stack 1126 may have any suitable period. It will be appreciated that the first stack 1122, the second stack 1123, and the third stack 1124 may be formed from a single feature. The periodic structure formed in the stack 1124 and the third stack 1126 It will be further understood that features may be formed from substructures. 1122, the second stack 1124, and the third stack 1126. The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. It is.

[0166] As seen in FIG. 11A, the four halves 1112, 1114, 1116, and 1118 A plurality of first shafts 1122 are disposed in each of the first stacks 1122 and intersect the first stacks 1122. 32 and intersects with the second stack 1124 and is located within the first plane 1131. A second plane 1133 including a plurality of second axes 1134 intersects with the third stack 1126. , and a third plane 1135 that includes a plurality of third axes 1136 located therein. The first stack 1 in each of the four halves 1112, 1114, 1116, and 1118 Depending on the orientation of the first stack 122, the second stack 1124, and the third stack 1126, Each of the first plane 1131, the second plane 1133, and the third plane 1135 is a plane parallel to the xz plane. or the yz plane, and a first axis 1132, a second axis 1134, and a third axis 1136 are parallel to the respective x-axis or y-axis. 16, and 1118, a first plane 1131, a second plane 1133, and It will be appreciated that the first and third planes 1135 are all parallel to one another.

[0167] As can be seen particularly in FIG. 11B, the first stack 1122 includes a first layer 1102 and a The first stack includes a first periodic structure (S1P1) 1142 formed in the first stack, 1142 is a graph of S1, designated as δ, along one of the first stack axes 1132. The first stack 1122 is formed with the second layer 1104. The first stack further includes a second periodic structure (S1P2) 1144, S1P2 114 4 is a distance S designated as δ-p along another of the first stack axes 1132. Preferably, the S1P2 pitch δ-p is a first pitch designated as p The first stack summation term p is different from the S1P1 pitch δ. It can have any value outside of this.

[0168] S1P1 1142 and S1P2 1144 at least partially overlap each other; Therefore, when imaging the first stack 1122, the first stack moire pattern 11 It will be appreciated that the first 50 can be seen. The stack moiré pattern 1150 has a pitch of ε 1 and pitch ε 1 teeth , which is a function of the summation term p, the pitch δ, and the pitch δ-p, as shown in Equation 26.

number

[0169] As can be seen particularly in FIG. 11C, the second stack 1124 is formed in conjunction with the first layer 1102. The first periodic structure (S2P1) 1152 of the second stack is formed on the first periodic structure (S2P1) 1152 of the second stack. 1152 is a graph of S2, designated as δ, along one of the second stack axes 1134. It is understood that the S2P1 pitch δ has the same value as the S1P1 pitch δ. As will be understood, the second stack 1124 is a second stack formed with the second layer 1104. The stack further includes a second periodic structure (S2P2) 1154, the S2P2 1154 being a first Along the other of the two stack axes 1134, an S2P2 peak designated as δ+p Preferably, the S2P2 pitch δ+p is equal to the second pitch designated as p. The second stack summation term p differs from the S2P1 pitch δ. It will be appreciated that this has the same value as the sum term p.

[0170] S2P1 1152 and S2P2 1154 at least partially overlap each other; Thus, when imaging the second stack 1124, the second stack moiré pattern 11 It will be appreciated that the second 60 can be seen as known in the art. The stack moiré pattern 1160 has a pitch of ε 2 and pitch ε 2 teeth , which is a function of the summation term p, the pitch δ, and the pitch δ+p, as shown in Equation 27.

number

[0171] As can be seen particularly in FIG. 11D, the third stack 1126, together with the second layer 1104, The third stack includes a first periodic structure (S3P1) 1162 formed on the first periodic structure (S3P1) 1162. 1162 is along one of the third stack axes 1136, designated as δ+p S3P1 pitch δ+p has the same value as S2P2 pitch δ+p It will be appreciated that the third stack 1126 is formed with the third layer 1106. The third stack further includes a second periodic structure (S3P2) 1164, 164 is a third stack axis 1136 along another of the stack axes, designated as δ. The S3P2 pitch δ can have the same value as the S1P1 pitch δ. Let it be understood.

[0172] S3P1 1162 and S3P2 1164 at least partially overlap each other; Thus, when imaging the third stack 1126, the third stack moire pattern 11 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stack moiré pattern 1170 has a pitch of ε 3 and pitch ε3 teeth , which is a function of the summation term p, the pitch δ, and the pitch δ+p, as shown in Equation 28.

number

[0173] Misalignment between any two of the layers 1102, 1104, and 1106 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches δ, δ-p, and δ+p are used to generate an image of the target 1100. It is not necessary that the optical resolution be sufficient for the misalignment measurement tool to be used. Pitch ε 1 , ε 2 , and ε 3 Each of these is used to generate an image of the target 1100. Preferably, the alignment is optically resolvable by a displacement metrology tool.

[0174] Referring now to FIG. 12A, FIG. 12A illustrates a multi-layer semiconductor formed by a target 1200. Layers 1002, 1004, and 1006 (FIG. 10), or 1102, of a device wafer; 1104, and 1106 (FIGS. 11A-11D), 204, and the third layer 1206 in a direction parallel to either the x-direction or the y-direction. In this way, a multi-layer mower such as target 1000 (FIG. 10) or target 1100 (FIGS. 11A-11D) can be used. 1 is a simplified flow diagram illustrating a preferred method for calculating misalignment using target 1200. Further referring to FIG. 12B and FIG. 12C, FIG. 12B and FIG. 12C show 12B are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIG. 12A, respectively.

[0175] When using target 1100 (FIGS. 11A-11D), please refer to FIGS. 12A-12C. The method described uses 1 It will be appreciated that the above steps may be performed only once, but typically are performed as described in FIGS. 12A-12C. The method described above is performed twice to calculate the displacement in each of the x and y directions. When using the target 1000 (FIG. 10), the first stack axis 1032, the second stack axis 1033, In one direction, the tack axis 1034 and the third stack axis 1036 are parallel. It will also be appreciated that the misregistration can be calculated by comparing the measured position and the measured distance.

[0176] As seen in the first step 1207, a direction in which to measure the misalignment is selected. When using the target 1000 in the manner of FIGS. 12A and 12B, the direction in which the displacement is measured is , a first stack shaft 1032, a second stack shaft 1034, and a third stack shaft 10 The method of FIG. 12A and FIG. 12B is automatically selected so that the direction of the arrows 36 is parallel. When using target 1100 in a 3D space, the structure of quadrants 1114 and 1118 is parallel to the x-axis. The structure of the quadrants 1112 and 1116 is used to measure the misalignment in the direction is used to measure the displacement in a direction parallel to the y-axis.

[0177] Preferably, in the next step 1209, the image of the target 1200 is captured using adjustable polarization, wavelength, The image is generated using an imaging position measurement tool having a setting of the number of apertures and a numerical aperture. An example of an image misalignment measurement tool is available from KLA Corp., Milpitas, Calif., USA. and Archer™ 700, available from Oration. n, β+n, δ, δ-p, and δ+p are used to generate an image of the target 1200. Note that the alignment measurement tool does not need to be optically resolvable by the alignment measurement tool being used. However, the pitch γ 1 , γ 2 , γ 3 , ε 1 , ε 2 , and ε 3 Each of the targets is Be optically resolvable by the misalignment measurement tool used to generate the image is preferred.

[0178] In the next step 1211, a first region of interest is generated, as seen in FIGS. 12B and 12C. 1212, a second region of interest 1214, and a third region of interest 1216 are In the quadrant selected in 7, the first stack 1022, the second stack 1024, and and the third stack 1026 (FIG. 10), or the first stack 1122, the second stack 11A to 11D), and the third stack 1124, and the third stack 1126 (FIGS. 11A to 11D), Each of the first stack 1222, the second stack 1224, and the third stack 1226 As can be seen in the illustrated embodiment of FIG. 12B and FIG. 12C, the first A first region of interest 1212, a second region of interest 1214, and a third region of interest 1216 are preferred. Alternatively, the first region of interest 1212 may be shown to be located entirely within the first stack 1222. As shown, each of the first stack 1222, the second stack 1224, and the third stack Although each of the stacks 1226 is entirely located, the first region of interest 1212, the second region of interest 1214 and a third region of interest 1216 are respectively associated with a second stack 1224 and As shown for the regions of interest 1214 and 1216 that extend beyond the third stack 1226. As shown in FIG. 1, each of the first stack 1222, the second stack 1224, and the third stack It will be appreciated that the conductor 1222 may extend beyond the block 1226. The regions of interest 1212, 1214, and 1216 shown in FIG. 1 are representative regions of interest. It will be further appreciated that other suitable regions of interest may also be selected in the drop 1211 .

[0179] In the next step 1231, as seen in FIG. 12B and FIG. 12C, The location of the symmetric points 1232 between all instances of the first region of interest 1212 selected in 1 In the next step 1233, as seen in Figures 12B and 12C, Symmetry between all instances of the second region of interest 1214 selected in step 1211 The location of point 1234 is calculated. In the next step 1235, the location of point 1234 is calculated as shown in FIG. 12. All the instances of the third region of interest 1216 selected in step 1211 are The location of the symmetric point 1236 between the chests is calculated.

[0180] In the next step 1237, the step 12 The location of the symmetric point 1232 of the first one or more regions of interest 1212 identified in step 31 and 1233 with the location of the symmetric point 1234 of the second one or more regions of interest 1214 identified in step 1233. The distance between is calculated. The distance found in step 1237 is used to calculate the gain ζ 1 Divided by And the gain ζ 1 For target 1000, the pitch β and the additive term It is a function of n.

number

number

[0181] In the next step 1239, the step 12 The location of the symmetric point 1234 of the second one or more regions of interest 1214 identified in step 33 and and the location of the symmetric point 1236 of the third one or more regions of interest 1216 identified in step 1235. The distance between the two is calculated. The distance found in step 1239 is used to calculate the gain ζ 2 Divided by And the gain ζ 2 For target 1000, the pitch β and the additive term It is a function of n.

number

number

[0182] In the next step 1241, the misalignment value reported in step 1237 and the 39 is calculated. is the second layer 1204 and the third layer 1206 in the direction selected in step 1207. This is reported as the misalignment between the two points. It will be appreciated that the method further calculates an adjustment direction, such as right, left, up, or down. The direction is a function of the pitch β and the summation term n or the pitch δ and the summation term p, and the layer Which of 1204 and 1206 is adjusted.

[0183] Preferably, it is shown formed with a first layer 1202 and a third layer 1206. In the embodiment described hereinabove, all of the structures shown are formed together with layer 1202. The method described herein above with reference to Figures 12A to 12C may include the step 1237 Calculating the difference between the misalignment value measured in step 1241 and the misalignment value reported in step 1242; The difference between the misregistration values ​​reported in steps 1237 and 1241 is calculated based on the difference in the misregistration values ​​reported in FIG. This is useful for calibrating the positional deviation measurement tool used in the methods of Figs. 2A to 12C.

[0184] In one embodiment of the present invention, the method described herein above with reference to Figures 12A-12C is The connecting portion is performed using only layers 1202 and 1204 before forming layer 1206. It will be understood that this is possible.

[0185] Reference is now made to FIG. 13, which illustrates another embodiment of a multi-layer moire target 1300 of the present invention. FIG. 13 is a simplified diagram of three different axes, indicated by the x-axis, y-axis, and z-axis. In this specification, these three dimensions are respectively referred to as the xy plane, the xz plane, and yz planes. FIG. 13 generally shows the xy plane, and enlarged views A, B, and C of FIG. Note that C denotes a plane parallel to the xz plane.

[0186] The target 1300 is preferably formed on a semiconductor device wafer and is preferably On the device wafer, at least a first layer 1302, a second layer 1304, and a third layer 1306 are formed. 306 is formed. The first layer 1302, the second layer 1304, and the third layer 1306 It will be appreciated that each defines a generally planar surface parallel to the xy plane. 2, the second layer 1304, and the third layer 1306 may be adjacent layers, This is not necessarily the case. Preferably, the first layer 1302, the second layer 1304, and the third layer Any material between the three layers 1306 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIG. 13, the first layer 1302 is made up of a second layer 1304 and a third layer 1305. 1306, which is located below the first layer 1302 and the second layer 1304. However, layers 1302, 1304, and 1306 are aligned along the z axis relative to one another. It will be appreciated that the numbers may be arranged in any suitable order along the length of the filter.

[0187] Additionally, in one embodiment of the present invention, the first layer 1302 and the third layer 1306, All of the structures shown as formed can be formed with layer 1302 In such an embodiment, no portion of the target 1300 is formed with the layer 1306. Such an embodiment may be described later in this specification with reference to Figures 15A-15C. Particularly useful for proofreading.

[0188] FIG. 13 shows one possible arrangement of a target 1300, and in other embodiments of the invention, the target It will be appreciated that 1300 can include additional structures. For example, FIG. As will be described later in this specification with reference to Figs. 14D and 34-39, a suitable target is 3, and the multiple instances of the structure shown in They can be arranged in a variety of ways.

[0189] Preferably, the target 1300 includes a first periodic structure stack 1322, a second periodic structure stack 1323, and a The first stack 1322 includes a first periodic structure stack 1324, and a third periodic structure stack 1326. Each of the first stack 1324 and the third stack 1326 includes one or more periodic structures. Preferably, the first stack 1322, the second stack 1323, and the third stack 1324 are arranged in a circular pattern. None of the stacks 1324 and the third stack 1326 overlap each other. .

[0190] In FIG. 13, a first stack 1322, a second stack 1324, and a third stack Each of the periodic structures in block 1326 is shown formed from a number of lines and spaces. However, in other embodiments of the present invention, the first stack 1322, the second stack 1324, and The periodic structure of the third stack 1326 may be formed from any suitable periodic features. It will be understood that the first stack 1322, the second stack 1324, and the The periodic features forming the periodic structure contained within the stack 1326 of three are formed from substructures. It will be further understood that the first stack 1322, the second stack 1 The pitch of each of the periodic structures of the first stack 1324 and the third stack 1326 is preferably 10 n The thickness is preferably from 200 nm to 3000 nm, and more preferably from 200 nm to 800 nm.

[0191] A first xz plane 1331 intersects with the first stack 1322. 32 lies in a first xz plane 1331 and is parallel to the x-axis. 3 intersects with the second stack 1324. A plurality of second axes 1334 are aligned in a second xz plane. 1333 and is parallel to the x-axis. A third xz plane 1335 is located within the third stack 1 326. A number of third axes 1336 lie in a third xz plane 1335 and It is parallel to the axis.

[0192] As can be seen particularly in the enlarged view A, the first stack 1322 together with the second layer 1304 The first stack includes a first periodic structure (S1P1) 1342 formed in the first stack, and S1P1 1342 is a graph of S1, designated as η, along one of the first stack axes 1332. Preferably, the first stack 1322 has a pitch of P1. The first one, which should produce a moiré pattern with S1P1 1342 when imaging It does not include a periodic structure formed with either the layer 1302 or the third layer 1306. However, the first stack 1322 is a periodic structure that is periodic along an axis parallel to the y-axis, or or a pitch size that does not produce a moire pattern when imaging the first stack 1322. A periodic structure having a periodicity such as a periodic structure having a periodicity that produces a moiré pattern when imaging the first stack 1322. The periodic structure formed with the first layer 1302 or the third layer 1306 does not interfere with the It is possible.

[0193] As can be seen particularly in the enlarged view B, the second stack 1324 is formed in conjunction with the first layer 1302. The first periodic structure (S2P1) 1352 of the second stack is formed on the first periodic structure (S2P1) 1352 of the second stack. 1352 is a S2 axis designated as θ along one of the second stack axes 1334. The second stack 1324 was formed with the second layer 1304. The second stack further includes a second periodic structure (S2P2) 1354, S2P2 135 4 along another of the second stack axes 1334, designated as ι It has two pitches.

[0194] S2P1 1352 and S2P2 1354 at least partially overlap each other; Thus, when imaging the second stack 1324, the second stack moiré pattern 13 It will be appreciated that the second 60 can be seen as known in the art. The stack moiré pattern 1360 has a pitch of κ 2 and pitch κ 2 teeth , which is a function of pitch θ and pitch ι, as shown in Equation 31.

number

[0195] As can be seen particularly in close-up C, the third stack 1326, together with the second layer 1304, The third stack includes a first periodic structure (S3P1) 1362 formed on the first periodic structure (S3P1) 1362. 1362 is a S3 axis designated as λ along one of the third stack axes 1336. The third stack 1326 was formed with the third layer 1306. The third stack further includes a second periodic structure (S3P2) 1364, S3P2 136 4 along another of the third stack axes 1336, designated as μ In one embodiment of the present invention, the S3P1 pitch λ and the S2P2 pitch ι The values ​​of S3P2 pitch μ and S2P1 pitch θ are identical.

[0196] S3P1 1362 and S3P2 1364 at least partially overlap each other; Thus, when imaging the third stack 1326, the third stack moiré pattern 13 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stack moiré pattern 1370 has a pitch of κ 3 and pitch κ 3 teeth , which is a function of pitch λ and pitch μ, as shown in Equation 32.

number

[0197] Misalignment between any two of layers 1302, 1304, and 1306 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches θ, ι, λ, and μ are used to generate an image of the target 1300. It is not necessary that the pitch be optically resolvable by the displacement measurement tool used. Chi η, κ 2 , and κ 3 Each of the positions is used to generate an image of the target 1300. It is preferably optically resolvable by a displacement measurement tool.

[0198] Referring now to FIGS. 14A-14D, FIGS. 14A-14D show a multi-layer moire target of the present invention. 14A-14D are simplified diagrams of another embodiment of a target 1400. , and z-axes, and these three The dimensions are referred to as the xy plane, the xz plane, and the yz plane, respectively. 14B, 14C, and 14D show planes parallel to the xz plane. I want to be loved.

[0199] Target 1400 is an example of an alternative arrangement of target 1300 described herein above with reference to FIG. and it is noted that additional sequences are described herein below with reference to Figures 34-39. The target 1400 is preferably formed on a semiconductor device wafer and is preferably a semiconductor On the device wafer, at least a first layer 1402, a second layer 1404, and a third layer 1406 is formed. The first layer 1402, the second layer 1404, and the third layer 1406 It will be appreciated that each of the first layer 14 defines a substantially planar surface parallel to the xy plane. 14.02, the second layer 1404, and the third layer 1406 may be adjacent layers. , but not necessarily. Preferably, the first layer 1402, the second layer 1404, and Any material between the third layer 1406 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIGS. 14A-14D, the first layer 1402 is and a third layer 1406, which is disposed below the first layer 1402 and the However, layers 1402, 1404, and 1406 are mutually It will be appreciated that the elements may be arranged in any suitable order along the z-axis relative to the object.

[0200] Additionally, in one embodiment of the present invention, the first layer 1402 and the third layer 1406, All of the structures shown as formed can be formed with layer 1402 In such an embodiment, no portion of the target 1400 is formed with the layer 1406. Such an embodiment may be described later in this specification with reference to Figures 15A-15C. Particularly useful for proofreading.

[0201] As can be seen particularly in FIG. 14A, the target 1400 is divided into four target halves 1412, 1413, 1414, 1415, 1416, 1417, 1418, 1419, 1420, 1421, 1422, 1423, 1424, 1425, 1426, 1427, 1428, 1429, 1430, 1431, 1432, 1433, 1434, 1435, 1436, 1437, 1438, 1439, 1440, 1441, 1442, 1443, 1444, 1445, 1446, 1447, 1448, 1449 14A, the target halves 1414, 1416, and 1418. The rotation directions in the xy plane of each of 1412, 1414, 1416, and 1418 are preferably , 1412, 1414, 1416, and 1417 are the other four halves of the target, which are integer multiples of 90°. 8 are different from each other in the xy plane. In addition, the target 1400 is preferably It is characterized by rotational symmetry in either the x or y direction or both. According to a preferred embodiment of the invention, when the target 1400 is in a superimposed state, the target 1 The entire 400 is bounded by a single point of symmetry in the x direction and a single point of symmetry in the y direction. However, even in such an embodiment, the alignment of the stator and the stator are not affected by the alignment of the stator and the stator. At times, various elements of the target 1400 are characterized by unique points of symmetry.

[0202] Each of the target halves 1412, 1414, 1416, and 1418 includes a first periodic structure. stack 1422, a second periodic structure stack 1424, and a third periodic structure stack 1 426. The first stack 1422, the second stack 1424, and the third stack Each of the blocks 1426 includes one or more periodic structures, each of which has a pitch. Generally, the first stack 1422, the second stack 1424, and the third stack 142 14A to 14D, the first stack 142 2 is the center of the target 1400 from the second stack 1424 and the third stack 1426. 14, the third stack 1426 is shown positioned adjacent to the first stack 14 22 and a second stack 1424 are shown positioned near the edge of the target 1400. However, the first stack 1422, the second stack 1424, and the third stack The stacks 1426 may be arranged in any suitable arrangement relative to each other in the xy plane. can.

[0203] In the embodiment shown in FIGS. 14A to 14D, a first stack 1422, a second stack 1 424, and the periodic structure of the third stack 1426 are each formed of a plurality of lines and spaces. Although shown in a completed state, in other embodiments of the present invention, the first stack 1422, The periodic structures of the second stack 1424 and the third stack 1426 may have any suitable period. It will be appreciated that the first stack 1422, the second stack 1423, and the third stack 1424 may be formed from a single feature. The periodic structures formed within stack 1424 and third stack 1426 are It will be further understood that features may be formed from substructures. 1422, the second stack 1424, and the third stack 1426. The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. It is.

[0204] As seen in FIG. 14A, four halves 1412, 1414, 1416, and 1418 A plurality of first shafts 14 intersect the first stack 1422 and are positioned therein. 32 and intersects with the second stack 1424 and is located within the first plane 1431. A second plane 1433 including a plurality of second axes 1434 intersects with the third stack 1426. , and a third plane 1435 that includes a plurality of third axes 1436 located therein. The first stack 1 in each of the four halves 1412, 1414, 1416, and 1418 Depending on the orientation of the first stack 422, the second stack 1424, and the third stack 1426, Each of the first plane 1431, the second plane 1433, and the third plane 1435 is a plane parallel to the xz plane. or the yz plane, and a first axis 1432, a second axis 1434, and a third axis 1436 are parallel to the respective x-axis or y-axis. 16, and 1418, a first plane 1431, a second plane 1433, and It will be appreciated that the first and second planes 1435 are all parallel to one another.

[0205] As can be seen particularly in FIG. 14B, the first stack 1422 together with the second layer 1404 The first stack includes a first periodic structure (S1P1) 1442 formed in the first stack, and S1P1 1442 is a S1, designated as ν, along one of the first stack axes 1432. Preferably, the first stack 1422 has a pitch of P1. The first one, which should produce a moiré pattern with S1P1 1442 when imaging It does not include a periodic structure formed with either layer 1402 or the third layer 1406 . However, the first stack 1422 is aligned along an axis perpendicular to the first stack axis 1432, i.e., x A periodic structure that is periodic in a plane parallel to the y-plane, or a first stack 1422, is imaged. The first structure may be a periodic structure having a pitch size that does not produce a moiré pattern when the first structure is rotated. The first layer 1402 or the second layer 1403 may be formed without causing a moiré pattern when imaging the block 1422. The periodic structure formed with the three layers 1406 may include:

[0206] As can be seen particularly in FIG. 14C, the second stack 1424 is formed in conjunction with the first layer 1402. The first periodic structure (S2P1) 1452 of the second stack is formed on the 1452 is a graph of the S2 axis, designated as ξ, along one of the second stack axes 1434. The second stack 1424 was formed with the second layer 1404. The second stack further includes a second periodic structure (S2P2) 1454, S2P2 145 4 is S2P designated as π along another of the second stack axes 1434. It has two pitches.

[0207] S2P1 1452 and S2P2 1454 at least partially overlap each other; Thus, when imaging the second stack 1424, the second stack moiré pattern 14 It will be appreciated that the second 60 can be seen as known in the art. The stack moiré pattern 1460 has a pitch ρ 2 and the pitch ρ 2 teeth , which is a function of pitch ξ and pitch π, as shown in Equation 33.

number

[0208] As can be seen particularly in FIG. 14D, the third stack 1426, together with the second layer 1404, The third stack includes a first periodic structure (S3P1) 1462 formed in the first periodic structure (S3P1) 1462. 1462 is a graph of S3, designated as σ, along one of the third stack axes 1436. The third stack 1426 was formed with the third layer 1406. The third stack further includes a second periodic structure (S3P2) 1464, S3P2 146 4 along another of the third stack axes 1436, designated as τ, In one embodiment of the present invention, the S3P1 pitch σ and the S2P2 pitch π The values ​​of τ and ξ are identical, and the values ​​of S3P2 pitch τ and S2P1 pitch ξ are identical.

[0209] S3P1 1462 and S3P2 1464 at least partially overlap each other; Thus, when imaging the third stack 1426, the third stack moiré pattern 14 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stack moiré pattern 1470 has a pitch ρ 3 and the pitch ρ 3 teeth , which is a function of pitch σ and pitch τ as shown in Equation 34.

number

[0210] Misalignment between any two of layers 1402, 1404, and 1406 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches ξ, π, σ, and τ are used to generate an image of the target 1400. It is not necessary that the pitch be optically resolvable by the displacement measurement tool used. Chiν, ρ 2 , and ρ 3 Each of the positions is used to generate an image of the target 1400. It is preferably optically resolvable by a displacement measurement tool.

[0211] Referring now to FIG. 15A, FIG. 15A illustrates a multi-layer semiconductor formed by a target 1500. Layers 1302, 1304, and 1306 (FIG. 13), or 1402, of a device wafer; 1404, and 1406 (FIGS. 14A-14D). 504, and a third layer 1506 in a direction parallel to either the x-direction or the y-direction. In this way, a multi-layer mower such as target 1300 (FIG. 13) or target 1400 (FIGS. 14A-14D) can be used. 1 is a simplified flow diagram illustrating a preferred method for calculating misalignment using target 1500. Further referring to FIG. 15B and FIG. 15C, FIG. 15B and FIG. 15C show that 15B are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIG. 15A, respectively.

[0212] When using target 1400 (FIGS. 14A-14D), please refer to FIGS. 15A-15C. The method described uses 1 It will be appreciated that the above steps may be performed only once, but typically are performed as described in FIGS. 15A-15C. The method described above is performed twice to calculate the displacement in each of the x and y directions. When using the target 1300 (FIG. 13), the first stack axis 1332, the second stack axis 1333, In one direction, the tack axis 1334 and the third stack axis 1336 are parallel. It will also be appreciated that the misregistration can be calculated by comparing the measured position and the measured distance.

[0213] As seen in the first step 1507, a direction in which to measure the misalignment is selected. When using the target 1300 in the manner of FIGS. 15A and 15B, the direction in which the displacement is measured is , a first stack axis 1332, a second stack axis 1334, and a third stack axis 13 36 is automatically selected so that it is parallel to the direction of the arrows 36. When using target 1400 in a 3D space, the structure of quadrants 1414 and 1418 is parallel to the x-axis. The structure of the quadrants 1412 and 1416 is used to measure the misalignment in the is used to measure the displacement in a direction parallel to the y-axis.

[0214] Preferably, in the next step 1509, the image of the target 1500 is captured using adjustable polarization, wavelength, The image is generated using an imaging position measurement tool having a setting of the number of apertures and a numerical aperture. An example of an image misalignment measurement tool is available from KLA Corp., Milpitas, Calif., USA. The pitch θ, ι, λ, μ, ξ, π, σ, and τ are the positions used to generate an image of the target 1500. Note that it is not necessary for the displacement measurement tool to be optically resolvable. , pitch η, ν, κ 2 , κ 3 , ρ 2 , and ρ 3 Each of these generates an image of the target 1500. Preferably, the alignment is optically resolvable by the alignment measurement tool used to measure alignment. .

[0215] In the next step 1511, a first region of interest is generated, as seen in FIGS. 15B and 15C. 1512, a second region of interest 1514, and a third region of interest 1516 are In the quadrant selected in 7, the first stack 1322, the second stack 1324, and and the third stack 1326 (FIG. 13), or the first stack 1422, the second stack 14A-14D), and the third stack 1424, and the third stack 1426 (FIGS. 14A-14D), Each of the first stack 1522, the second stack 1524, and the third stack 1526 As can be seen in the illustrated embodiment of FIG. 15B and FIG. 15C, the first A first region of interest 1512, a second region of interest 1514, and a third region of interest 1516 are preferred. Alternatively, a first region of interest 1512 located entirely within the first stack 1522 may be shown. As shown, each of the first stack 1522, the second stack 1524, and the third stack Although each of the stacks 1526 is entirely located, the first region of interest 1512, the second region of interest 1514 and a third region of interest 1516 are respectively associated with a second stack 1524 and As shown for the regions of interest 1514 and 1516 that extend beyond the third stack 1526. As shown in FIG. 1, each of the first stack 1522, the second stack 1524, and the third stack It will be appreciated that the conductor 1522 may extend beyond the block 1526. The regions of interest 1512, 1514, and 1516 shown in FIG. 1 are representative regions of interest. It will be further appreciated that other suitable regions of interest may also be selected in the drop 1511 .

[0216] In the next step 1531, as seen in FIG. 15B and FIG. 15C, The location of symmetric points 1532 between all instances of the first region of interest 1512 selected in 1 In the next step 1533, as seen in Figures 15B and 15C, Symmetry between all instances of the second region of interest 1514 selected in step 1511 The location of point 1534 is calculated. In the next step 1535, the location of point 1534 is calculated as shown in FIG. 15. All the instances of the third region of interest 1516 selected in step 1511 are The location of the symmetric point 1536 between the chests is calculated.

[0217] In the next step 1537, the step 15 The location of the symmetric point 1532 of the first one or more regions of interest 1512 identified in step 31 and 1533 with the location of the symmetric point 1534 of the second one or more regions of interest 1514 identified in step 1533. The distance between the two points is calculated. The distance found in step 1537 is calculated based on the gain υ 1 Divided by and the gain υ 1 For target 1300, pitch θ and pitch It is a function of ι.

number

number

[0218] In the next step 1539, the step 15 The location of the symmetric point 1532 of the first one or more regions of interest 1512 identified in step 31 and 1535 with the location of the symmetric point 1536 of the third one or more regions of interest 1516 identified in step 1535. The distance between the gains υ is calculated. 2 Divided by and the gain υ 2 For target 1300, pitch λ and pitch It is a function of μ.

number

number

[0219] In the next step 1541, the misregistration value between the first layer 1502 and the third layer 1506 is If the S3P1 pitch does not have the same value as the S2P2 pitch, In the embodiment described above in which does not have the same value as the S2P1 pitch, In 1541, the misalignment value reported in step 1537 and the misalignment value reported in step 1539 are The difference between the misalignment value calculated in step 1541 and the misalignment value calculated in step 1542 is calculated. Misalignment between the first layer 1502 and the third layer 1506 in a direction selected at 507 In addition to the distance calculated in step 1541, the method also calculates the distance to the right, left, It will be appreciated that the adjustment direction, such as up or down, may also be calculated. A function of the relative values ​​of θ and pitch ι or pitch π and pitch ξ, and layers 1502 and The question is which of 1506 and 1507 is adjusted.

[0220] The S3P1 pitch has the same value as the S2P2 pitch, and the S3P2 pitch is In the embodiment described above in this specification, in step 1541, 07 in the direction selected, the second one or more regions of interest identified in step 1533. The location of the symmetric point 1534 of the region 1514 and the third one or more identified in step 1535 The distance between the location of the symmetric point 1536 of the region of interest 1516 is calculated. The distance found at is the gain υ 3 The gain υ is divided by 3 For target 1300, etc. is a function of pitch θ and pitch ι, as shown in Equation 37a.

number

number

[0221] Preferably, it is shown formed with a first layer 1502 and a third layer 1506. In the embodiment described herein above, all of the structures shown are formed together with layer 1502. The method described herein above with reference to Figures 15A to 15C may include, in step 1537, Calculating the difference between the misalignment value measured in step 1530 and the misalignment value reported in step 1539; The difference between the misalignment values ​​reported in steps 1537 and 1539 is calculated based on the difference in the misalignment values ​​reported in FIG. This is useful for calibrating the positional deviation measurement tool used in the methods of Figs. 5A to 15C.

[0222] In one embodiment of the present invention, the method described herein above with reference to Figures 15A-15C is The connecting portion is performed using only layers 1502 and 1504 before forming layer 1506. Similarly, it will be appreciated that layer 1506 may be disposed below layer 1502. In one embodiment of the invention, the relevant portion of the method described herein above with reference to Figures 15A-15C. This step should be performed using only layers 1504 and 1506 before forming layer 1502. This can be done.

[0223] Reference is now made to FIG. 16, which illustrates another embodiment of a multi-layer moire target 1600 of the present invention. FIG. 16 is a simplified diagram of three different axes, indicated by the x-axis, y-axis, and z-axis. In this specification, these three dimensions are respectively referred to as the xy plane, the xz plane, and yz planes. FIG. 16 generally shows the xy plane, and enlargements A, B, and C of FIG. Note that C denotes a plane parallel to the xz plane.

[0224] The target 1600 is preferably formed on a semiconductor device wafer and is preferably On the device wafer, at least a first layer 1602, a second layer 1604, and a third layer 1606 are formed. 606 is formed. The first layer 1602, the second layer 1604, and the third layer 1606 It will be appreciated that each defines a generally planar surface parallel to the xy plane. 2, the second layer 1604, and the third layer 1606 may be adjacent layers, This is not necessary. Preferably, the first layer 1602, the second layer 1604, and the third layer Any material between the three layers 1606 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIG. 16, the first layer 1602 is made up of a second layer 1604 and a third layer 1605. 1606, which is located below the first layer 1602 and the second layer 1604. However, layers 1602, 1604, and 1606 are aligned along the z axis relative to one another. It will be appreciated that the numbers may be arranged in any suitable order along the length of the filter.

[0225] Additionally, in one embodiment of the present invention, the first layer 1602 and the second layer 1604, All of the structures shown as formed can be formed with layer 1602 In such an embodiment, no portion of the target 1600 is formed with the layer 1604. Such an embodiment may be described later in this specification with reference to Figures 18A-18C. This is particularly useful for calibration. In addition, in another embodiment of the present invention, the first layer 1602 and All of the structures shown formed with layers 1602 and 1606 are In such an embodiment, any portion of the target 1600 may be formed with Such an embodiment is not formed with layer 1606. See Figures 18A-18C. This is particularly useful for calibration, as will be explained later in this specification.

[0226] FIG. 16 shows one possible arrangement of a target 1600, and in other embodiments of the invention, the target It will be appreciated that 1600 can include additional structures. For example, FIG. As will be described later in this specification with reference to Figs. 17D and 34-39, a suitable target is 6, and the multiple instances of the structure shown in They can be arranged in a variety of ways.

[0227] Preferably, the target 1600 includes a first periodic structure stack 1622, a second periodic structure stack 1623, and a The first stack 1622 includes a first periodic structure stack 1624, and a third periodic structure stack 1626. Each of the first stack 1624 and the third stack 1626 includes one or more periodic structures. Preferably, the first stack 1622, the second stack 1623, and the third stack 1624 are arranged in a circular pattern. Neither stack 1624 nor the third stack 1626 overlaps with each other. .

[0228] In FIG. 16, a first stack 1622, a second stack 1624, and a third stack Each of the periodic structures in block 1626 is shown formed from a number of lines and spaces. However, in other embodiments of the present invention, the first stack 1622, the second stack 1624, and The periodic structure of the third stack 1626 may be formed from any suitable periodic features. It will be understood that the first stack 1622, the second stack 1624, and the The periodic features forming the periodic structure contained within the stack 1626 of three are formed from substructures. It will be further understood that the first stack 1622, the second stack 1 The pitch of each of the periodic structures of the third stack 1624 and the third stack 1626 is preferably 10 n The thickness is preferably from 200 nm to 3000 nm, and more preferably from 200 nm to 800 nm.

[0229] A first xz plane 1631 intersects with the first stack 1622. 32 lies in a first xz plane 1631 and is parallel to the x-axis. 3 intersects with the second stack 1624. A plurality of second axes 1634 are aligned in a second xz plane. 1633 and is parallel to the x-axis. A third xz plane 1635 is located within the third stack 1 626. A number of third axes 1636 lie in a third xz plane 1635 and It is parallel to the axis.

[0230] As can be seen particularly in Enlarged View A, the first stack 1622 together with the second layer 1604 The first stack includes a first periodic structure (S1P1) 1642 formed in the first stack, and S1P1 1642 is a S1, designated as φ, along one of the first stack axes 1632. Preferably, the first stack 1622 has a pitch of P1. The first one, which should produce a moiré pattern with S1P1 1642 when imaging It does not include a periodic structure formed with either layer 1602 or the third layer 1606 . However, the first stack 1622 is a periodic structure that is periodic along an axis parallel to the y-axis, or or a pitch size that does not produce a moire pattern when imaging the first stack 1622. A periodic structure having a periodicity such as a periodic structure having a periodicity that produces a moiré pattern when imaging the first stack 1622. The periodic structure formed with the first layer 1602 or the third layer 1606 does not interfere with the It is possible.

[0231] As can be seen particularly in close-up B, the second stack 1624 is formed in conjunction with the first layer 1602. The second stack includes a first periodic structure (S2P1) 1652 formed on the first stack. Along one of the block axes 1634, the S2P1 pitch is designated as χ. Preferably, the second stack 1624 is imaged by S1P 1 1652, which would produce a moiré pattern. The second stack does not include a periodic structure formed with any of the layers 1606. 1624 is a periodic structure that is periodic along an axis parallel to the y-axis, or a second stack 16 A periodic structure having a pitch size that does not produce a moire pattern when imaging 24. , the second layer 1624 does not produce a moiré pattern when imaging the second stack 1624. 16. The second layer 1604 may include a periodic structure formed with the third layer 1606.

[0232] As can be seen particularly in close-up C, the third stack 1626, together with the second layer 1604, The third stack includes a first periodic structure (S3P1) 1662 formed on the first periodic structure (S3P1) 1662. 1662 is a S3 axis designated as ψ along one of the third stack axes 1636. The third stack 1626 was formed with the third layer 1606. The third stack further includes a second periodic structure (S3P2) 1664, S3P2 166 4 along another of the third stack axes 1636, designated as ω It has two pitches.

[0233] S3P1 1662 and S3P2 1664 at least partially overlap each other; Thus, when imaging the third stack 1626, the third stack moiré pattern 16 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stacked moire pattern of 1670 is pitch "Hebrew Letter 1" which is a function of pitch ψ and pitch ω, as shown in Equation 38. be.

number

[0234] The misalignment between any two of the layers 1602, 1604, and 1606 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches ψ and ω are the positions used to generate an image of the target 1600. It is not necessary that the pitches φ, χ, and "Hebrew Letters 2" Each of the targets 1600 is measured by a misalignment measurement tool used to generate an image of the target 1600. It is preferred that the optically resolvable molecule is optically resolvable.

[0235] Referring now to FIGS. 17A-17D, which show a multi-layer moire target of the present invention. 17A-17D are simplified diagrams of another embodiment of a target 1700. , and z-axes, and these three The dimensions are called the xy plane, the xz plane, and the yz plane, respectively. 17B, ​​17C, and 17D show planes parallel to the xz plane. I want to be loved.

[0236] Target 1700 is an example of an alternative arrangement of target 1600 described herein above with reference to FIG. and it is noted that additional sequences are described herein below with reference to Figures 34-39. The target 1700 is preferably formed on a semiconductor device wafer and is preferably a semiconductor On the device wafer, at least a first layer 1702, a second layer 1704, and a third layer The first layer 1702, the second layer 1704, and the third layer 1706 are formed. It will be appreciated that each of the first layer 17 defines a substantially planar surface parallel to the xy plane. 17.02, the second layer 1704, and the third layer 1706 may be adjacent layers. , but not necessarily. Preferably, the first layer 1702, the second layer 1704, and Any material between the third layer 1706 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIGS. 17A-17D, the first layer 1702 is and a third layer 1706, which is disposed below the first layer 1702 and the However, layers 1702, 1704, and 1706 are mutually It will be appreciated that the elements may be arranged in any suitable order along the z-axis relative to the object.

[0237] Additionally, in one embodiment of the present invention, the first layer 1702 and the second layer 1704, All of the structures shown as formed can be formed with layer 1702 In such an embodiment, no portion of the target 1700 is formed with the layer 1704. Such an embodiment may be described later in this specification with reference to Figures 18A-18C. This is particularly useful for calibration. In addition, in another embodiment of the present invention, the first layer 1702 and All of the structures shown formed with layers 1702 and 1706 are In such an embodiment, any portion of the target 1700 may be formed with Such an embodiment is not formed with layer 1706. See Figures 18A-18C. This is particularly useful for calibration, as will be explained later in this specification.

[0238] As can be seen particularly in FIG. 17A, the target 1700 is divided into four target quads 1712, 1713, 1714, 1715, 1716, 1717, 1718, 1719, 1720, 1721, 1722, 1723, 1724, 1725, 1726, 1727, 1 4, 1716, and 1718. In the embodiment shown in FIG. 17A, the target halves 171 The rotation directions in the xy plane of each of 1712, 1714, 1716, and 1718 are preferably , 90° integer multiples, the other four halves of targets 1712, 1714, 1716, and 171 8 are different from each other in the xy plane. In addition, the target 1700 is preferably It is characterized by rotational symmetry in either the x or y direction or both. According to a preferred embodiment of the invention, when target 1700 is in a superimposed state, target 1 The entire 700 is bounded by a single point of symmetry in the x direction and a single point of symmetry in the y direction. However, even in such an embodiment, the alignment of the stator and the stator are not affected by the alignment of the stator and the stator. At times, various elements of the target 1700 are characterized by unique points of symmetry.

[0239] Each of the target halves 1712, 1714, 1716, and 1718 includes a first periodic structure. stack 1722, a second periodic structure stack 1724, and a third periodic structure stack 1 726. The first stack 1722, the second stack 1724, and the third stack Each of the blocks 1726 includes one or more periodic structures, each of which has a pitch. Generally, the first stack 1722, the second stack 1724, and the third stack 172 17A to 17D, the first stack 172 2 is the center of the target 1700 from the second stack 1724 and the third stack 1726. 17, the third stack 1726 is shown positioned adjacent to the first stack 17 22 and a second stack 1724 are shown positioned near the edge of the target 1700. However, the first stack 1722, the second stack 1724, and the third stack The stacks 1726 may be arranged in any suitable arrangement relative to each other in the xy plane. can.

[0240] In the embodiment shown in FIGS. 17A to 17D, a first stack 1722, a second stack 1 724, and the periodic structure of the third stack 1726 are each formed of a plurality of lines and spaces. Although shown in a completed state, in other embodiments of the present invention, the first stack 1722, The periodic structures of the second stack 1724 and the third stack 1726 may have any suitable period. It will be appreciated that the first stack 1722, the second stack 1723, and the third stack 1724 may be formed from a single feature. The periodic structures formed within stack 1724 and third stack 1726 are It will be further understood that features may be formed from substructures. 1722, the second stack 1724, and the third stack 1726. The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. It is.

[0241] As seen in FIG. 17A, four halves 1712, 1714, 1716, and 1718 A plurality of first shafts 1721 intersect the first stack 1722 and are positioned therein. 32 and intersects with the second stack 1724 and is located within the first plane 1731. A second plane 1733 including a plurality of second axes 1734 intersects with the third stack 1726. , and a third plane 1735 that includes a plurality of third axes 1736 located therein. The first stack 1 in each of the four halves 1712, 1714, 1716, and 1718 Depending on the orientation of the first stack 722, the second stack 1724, and the third stack 1726, Each of the first plane 1731, the second plane 1733, and the third plane 1735 is a plane parallel to the xz plane. or the yz plane, and a first axis 1732, a second axis 1734, and a third axis 1736 are parallel to the respective x-axis or y-axis. 16, and 1718, a first plane 1731, a second plane 1733, and It will be appreciated that the first and third planes 1735 are all parallel to one another.

[0242] As can be seen particularly in FIG. 17B, the first stack 1722, together with the second layer 1704, The first stack includes a first periodic structure (S1P1) 1742 formed in the first stack, 1742 is a graph of S1, designated as Γ, along one of the first stack axes 1732. Preferably, the first stack 1722 has a pitch of P1. The first one, which should produce a moiré pattern with S1P1 1742 when imaging It does not include a periodic structure formed with either layer 1702 or the third layer 1706. However, the first stack 1722 is rotated along an axis perpendicular to the first stack axis 1732, i.e., x A periodic structure that is periodic in a plane parallel to the y-plane, or a first stack 1722, is imaged. The first structure may be a periodic structure having a pitch size that does not produce a moiré pattern when the first structure is rotated. The first layer 1702 or the second layer 1703 may be formed without causing a moiré pattern when imaging the block 1722. The periodic structure formed with the three layers 1706 may include:

[0243] As can be seen particularly in FIG. 17C, the second stack 1724 is formed in conjunction with the first layer 1702. The first periodic structure (S2P1) 1752 of the second stack is formed on the first periodic structure (S2P1) 1752 of the second stack. 1752 is a graph of the S2 axis, designated as Θ, along one of the second stack axes 1734. Preferably, the second stack 1724 has a pitch of P1. The second, which should produce a moiré pattern with S1P1 1752 when imaging It does not include a periodic structure formed with either layer 1704 or the third layer 1706 . However, the second stack 1724 is rotated along an axis perpendicular to the second stack axis 1734, i.e., x A periodic structure that is periodic in a plane parallel to the y-plane, or a second stack 1724, is imaged. The second structure may be a periodic structure having a pitch size that does not result in a moiré pattern when the second structure is rotated. The second layer 1704 or the first layer 1724 may be formed without causing a moiré pattern when imaging the block 1724. The periodic structure formed with the three layers 1706 may include:

[0244] As can be seen particularly in FIG. 17D, the third stack 1726, together with the second layer 1704, The third stack includes a first periodic structure (S3P1) 1762 formed on the first periodic structure (S3P1) 1762. 1762 is a S3 axis designated as Λ along one of the third stack axes 1736. The third stack 1726 was formed with the third layer 1706. The third stack further includes a second periodic structure (S3P2) 1764, S3P2 176 4 along another of the third stack axes 1736, designated as S3P It has two pitches.

[0245] S3P1 1762 and S3P2 1764 at least partially overlap each other; Thus, when imaging the third stack 1726, the third stack moiré pattern 17 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stacked moiré pattern 1770 has a pitch of Π 3 and is characterized by the pitch Π 3 teeth , which is a function of pitch Λ and pitch Ξ, as shown in Equation 39.

number

[0246] Misalignment between any two of layers 1702, 1704, and 1706 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. The pitches Λ and Ξ are the positions used to generate the image of the target 1700. It is not necessary that the pitches Γ, Θ, and Π 3 Each of the three is a displacement measurement tool used to generate an image of the target 1700. It is preferable that the optically resolvable molecule is optically resolvable by a filter.

[0247] Referring now to FIG. 18A, FIG. 18A illustrates a multi-layer semiconductor formed by a target 1800. Layers 1602, 1604, and 1606 (FIG. 16), or 1702, of a device wafer; The first layer 1802, the second layer 1804, and the like, such as 1706 (FIGS. 17A-17D), 804, and a third layer 1806 in a direction parallel to either the x-direction or the y-direction. In this way, a multi-layer mower such as target 1600 (FIG. 16) or target 1700 (FIGS. 17A-17D) can be used. 1 is a simplified flow diagram illustrating a preferred method for calculating misalignment using target 1800. Further referring to FIG. 18B and FIG. 18C, FIG. 18B and FIG. 18C show that 18B are simplified pictorial diagrams of first and second embodiments of a portion of the method of FIG. 18A, respectively.

[0248] When using target 1700 (FIGS. 17A-17D), please refer to FIGS. 18A-18C. The method described uses 1 It will be appreciated that the above steps may be performed only once, but typically are performed as described in FIGS. 18A-18C. The method described above is performed twice to calculate the displacement in each of the x and y directions. When using the target 1600 (FIG. 16), the first stack axis 1632, the second stack axis 1633, In one direction, the tack axis 1634 and the third stack axis 1636 are parallel. It will also be appreciated that the misregistration can be calculated by comparing the measured position and the measured distance.

[0249] As seen in the first step 1807, a direction in which to measure the misalignment is selected. When using the target 1600 in the manner of FIGS. 18A and 18B, the direction in which the displacement is measured is , the first stack shaft 1632, the second stack shaft 1634, and the third stack shaft 16 36 is automatically selected to be parallel to the direction of the arrows 36. When using target 1700 in the axial direction, the structure of quadrants 1714 and 1718 is parallel to the x-axis. The structure of the quadrants 1712 and 1716 is used to measure the misalignment in the direction is used to measure the displacement in a direction parallel to the y-axis.

[0250] Preferably, in the next step 1809, the image of the target 1800 is imaged with adjustable polarization, wavelength, The image is generated using an imaging position measurement tool having a setting of the number of apertures and a numerical aperture. An example of an image misalignment measurement tool is available from KLA Corp., Milpitas, Calif., USA. The Archer™ 700 is commercially available from Oration. Λ, and Ξ are the displacement measurement tools used to generate the image of the target 1800. Note that it is not necessary for the pitches φ, χ, "Hebrew Letters 3" , Γ, Θ, and Π 3 Each of the positions is used to generate an image of the target 1800. Preferably, the optical resolution is possible by a metrology tool.

[0251] In the next step 1811, a first region of interest is generated, as seen in FIG. 18B and FIG. 18C. 1812, a second region of interest 1814, and a third region of interest 1816 are In the quadrant selected in 7, a first stack 1622, a second stack 1624, and and third stack 1626 (FIG. 16), or first stack 1722, second stack 17A-17D), and the third stack 1724, and the third stack 1726 (FIGS. 17A-17D). Each of the first stack 1822, the second stack 1824, and the third stack 1826 As can be seen in the illustrated embodiment of FIG. 18B and FIG. 18C, the first A first region of interest 1812, a second region of interest 1814, and a third region of interest 1816 are preferred. Alternatively, a first region of interest 1812 located entirely within a first stack 1822 may be shown. As shown, each of the first stack 1822, the second stack 1824, and the third stack Although each of the stacks 1826 is entirely located, the first region of interest 1812, the second region of interest 1814 and a third region of interest 1816 are respectively associated with a second stack 1824 and As shown for the regions of interest 1814 and 1816 that extend beyond the third stack 1826. As shown in FIG. 1, each of the first stack 1822, the second stack 1824, and the third stack It will be appreciated that the stator 1822 may extend beyond the lock 1826. The regions of interest 1812, 1814, and 1816 shown in FIG. 1 are representative regions of interest. It will be further appreciated that other suitable regions of interest may also be selected in the drop 1811.

[0252] In the next step 1831, as seen in FIG. 18B and FIG. 18C, The location of the symmetric points 1832 between all instances of the first region of interest 1812 selected in 1 In the next step 1833, as seen in Figures 18B and 18C, Symmetry between all instances of the second region of interest 1814 selected in step 1811 The location of point 1834 is calculated. In the next step 1835, the location of point 1834 is calculated as shown in FIG. 18. All the instances of the third region of interest 1816 selected in step 1811 are The location of the symmetric point 1836 between the chests is calculated.

[0253] In the next step 1837, the step 18 The location of the symmetric point 1832 of the first one or more regions of interest 1812 identified in step 31 and 18. The location of the symmetric point 1834 of the second one or more regions of interest 1814 identified in step 1833. The distance between the selected points in step 1807 is calculated. The measured misalignment is reported as the misalignment between the first layer 1802 and the second layer 1804 in the measured direction. In addition to the distance calculated in step 1837, the method also calculates the distance to the right, left, up, or down. It will be understood that the adjustment direction is further calculated, such as the symmetric point 1832 and and 1834, as well as which of layers 1802 and 1806 are adjusted. It is probably.

[0254] In the next step 1839, the step 18 The location of the symmetric point 1832 of the first one or more regions of interest 1812 identified in step 31 and 18. The location of the symmetric point 1836 of the third one or more regions of interest 1816 identified in step 1835. The distance between is calculated. The distance found in step 1839 is 1 Divided by and the gain Ω 1 For target 1600, pitch ψ and pitch It is a function of ω.

number

number

[0255] In the next step 1841, the misalignment value reported in step 1837 and the 39 is calculated. is a first layer 1802 and a third layer 1806 in the direction selected in step 1807. This is reported as the misalignment between the two points. In addition to the distance calculated in step 1841, It will be appreciated that the method further calculates an adjustment direction, such as right, left, up, or down. The direction is a function of the relative values ​​of pitch ψ and pitch ω or pitch Λ and pitch Ξ, and Which of layers 1802 and 1806 is adjusted is the most important factor.

[0256] Preferably, it is shown formed with a first layer 1802 and a second layer 1804. In the embodiment described herein above, all of the structures shown are formed together with layer 1802. The method described herein above with reference to Figures 18A-18C may include, in step 1839, Calculating the difference between the misalignment value measured in step 1841 and the misalignment value reported in step 1842; The difference between the misalignment values ​​reported in steps 1839 and 1841 is calculated based on the difference in the misalignment values ​​reported in FIG. This is useful for calibrating the positional deviation measurement tool used in the methods of FIGS. 8A to 18C.

[0257] Preferably, it is shown formed with a first layer 1802 and a third layer 1806. In the embodiment described hereinabove, all of the structures shown are formed together with layer 1802. The method described herein above with reference to Figures 18A-18C may include, in step 1837, Calculating the difference between the misalignment value measured in step 1830 and the misalignment value reported in step 1839; The difference between the misalignment values ​​reported in steps 1837 and 1839 is calculated based on the difference in the misalignment values ​​reported in FIG. This is useful for calibrating the positional deviation measurement tool used in the methods of FIGS. 8A to 18C.

[0258] In one embodiment of the present invention, the method described herein above with reference to Figures 18A-18C is The connecting portion is performed using only layers 1802 and 1804 before forming layer 1806. Similarly, it will be appreciated that layer 1806 may be disposed below layer 1802. In one embodiment of the invention, the relevant portion of the method described herein above with reference to Figures 18A-18C. This step should be performed using only layers 1804 and 1806 before forming layer 1802. This can be done.

[0259] Referring now to FIGS. 19A-19D, which show a multi-layer moire target of the present invention. 19A-19D are simplified diagrams of another embodiment of a target 1900. , and z-axes, and these three The dimensions are called the xy plane, the xz plane, and the yz plane, respectively. 19B, 19C, and 19D show planes parallel to the xz plane. I want to be loved.

[0260] The target 1900 is preferably formed on a semiconductor device wafer and is preferably On the device wafer, at least a first layer 1902, a second layer 1904, a third layer 1906 , and a fourth layer 1908 are formed. The layer 1906 and the fourth layer 1908 each define a substantially planar surface parallel to the xy plane. It will be understood that the first layer 1902, the second layer 1904, the third layer 1906, and The first and fourth layers 1908 can be, but are not required to be, adjacent layers. Preferably, the first layer 1902, the second layer 1904, the third layer 1906, and the fourth layer 1907 are Any material between 908 is at least partially transparent to electromagnetic radiation. In the embodiment shown in Figures 9A-19D, a first layer 1902 is formed from a second layer 1904, a third layer 1905, and a The second layer 1904 is located below the third layer 1906 and the fourth layer 1908. 1902, 1903, 1904, 1905, 1906, 1907, 1908, and 1909. 1904, and a third layer 1906. However, layers 1902, 1904 , 1906, and 1908 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that it is possible.

[0261] Additionally, in one embodiment of the present invention, the second layer 1904 and the third layer 1906 All of the structures shown as formed can be formed with layer 1904. In such an embodiment, no portion of the target 1900 is formed with the layer 1906. Such an embodiment may be described later in this specification with reference to Figures 21A-21C. This is particularly useful for calibration. In addition, in another embodiment of the present invention, the second layer 1904 and All of the structures shown formed with layers 1904 and 1908 are shown in FIG. In such an embodiment, any portion of the target 1900 may be formed with Such an embodiment is not formed with layer 1908. See Figures 21A-21C. This is particularly useful for calibration, as described later in this specification. In the embodiment shown, the third layer 1906 and the fourth layer 1908 are formed. All of the structures shown can be formed together with layer 1906. In such an embodiment, 1908. In such an embodiment, no portion of the target 1900 is formed with the layer 1908. This is particularly useful for calibration, as described later in this specification with reference to Figures 21A-21C. do.

[0262] 19A-19D show one possible arrangement of a target 1900, in accordance with another embodiment of the present invention. In some embodiments, it will be appreciated that the target 1900 may include additional structures. For example, As will be described later in this specification with reference to Figures 20A-20D and Figures 34-39, a preferred A target may include multiple instances of the structures shown in Figures 19A-19D. Multiple instances of can be arranged in a variety of ways.

[0263] Preferably, the target 1900 includes a first periodic structure stack 1922, a second periodic structure stack 1923, and a The first stack 1922 includes a first periodic structure stack 1924, and a third periodic structure stack 1926. Each of the first stack 1924 and the third stack 1926 includes one or more periodic structures. Preferably, the first stack 1922, the second stack 1923, and the third stack 1924 are arranged in a circular pattern. Neither stack 1924 nor the third stack 1926 overlaps with each other. .

[0264] In FIGS. 19A-19D, a first stack 1922, a second stack 1924, and Each of the periodic structures of the third stack 1926 is formed from a plurality of lines and spaces. 19, in other embodiments of the present invention, a first stack 1922, a second stack The periodic structure of the third stack 1924, and the third stack 1926 may be formed of any suitable periodic features. It will be understood that the first stack 1922, the second stack 192 4, and the periodic features forming the periodic structure contained within the third stack 1926 are It will be further understood that the first stack 1922, the second stack 1923, and the third stack 1924 may be formed from the same structure. The pitch of each of the periodic structures of the first stack 1924 and the third stack 1926 is preferably The thickness is preferably 10 nm to 3000 nm, and more preferably 200 nm to 800 nm.

[0265] A first xz plane 1931 intersects with the first stack 1922. 32 is located in a first xz plane 1931 and is parallel to the x-axis. 3 intersects with the second stack 1924. A plurality of second axes 1934 are aligned in a second xz plane. 1933 and is parallel to the x-axis. A third xz plane 1935 is located within the third stack 1 926. A number of third axes 1936 lie in a third xz plane 1935 and It is parallel to the axis.

[0266] As can be seen particularly in FIG. 19B, the first stack 1922 includes a first layer 1902. The first stack includes a first periodic structure (S1P1) 1942 formed on the first stack, 1942 along one of the first stack axes 1932, "Hebrew Letter 4" The first stack 1922 has a pitch designated as S1P1. 4, and further includes a second periodic structure (S1P2) 1944 of the first stack formed with 19, S1P2 1944 is aligned along another of the first stack axes 1932. "Hebrew Letter 5" The pitch is designated as S1P2.

[0267] S1P1 1942 and S1P2 1944 at least partially overlap each other; Thus, when imaging the first stack 1922, the first stack moiré pattern 19 It will be appreciated that the first 50 can be seen. The stacked moire pattern of 1950 is pitch "Hebrew Letter 6" Characterized by pitch "Hebrew Letter 7" is the pitch as shown in Equation 41. "Hebrew Letter 8" and "Hebrew letter 9" is a function of .

number

[0268] As can be seen particularly in FIG. 19C, the second stack 1924 is formed in conjunction with the first layer 1902. a first periodic structure (S2P1) 1952 of a second stack formed on the first periodic structure (S2P1) 1952 along one of the second stack axes 1934, "Hebrew Letter 10" Preferably, the S2P1 pitch is "Hebrew Letter 11" is multiplied by the second stack multiplication factor, designated as q, to ​​produce the S1P1 pitch. "Hebrew Letter 12" The second stack multiplication factor q can be any positive number. The second stack 1924 is a second layer of the second stack formed with the third layer 1906. The second stack axis is a second stack axis 1954. Along with another one of 1934, "Hebrew Letter 13" Preferably, the S2P2 pitch is "Hebrew Letter 14" is the S1P2 pitch by the second stack multiplication factor q. "Hebrew Letter 15" It is related to the S2P2 pitch. "Hebrew Letter 16" S1P2 pitch "Hebrew Letter 17" The second stack multiplication factor q, which relates to the S2P1 pitch "Hebrew Letter 18" S1P1 pitch "Hebrew Letter 19" It will be appreciated that the second stack multiplication factor q relating In one embodiment, the value of q is 1, and therefore the S2P1 pitch "20 Hebrew letters" is S1P1 pitch "Hebrew Letter 21" The pitch is the same as S2P2. "22 Hebrew letters" is S1P2 pitch "23 Hebrew letters" is identical to

[0269] S2P1 1952 and S2P2 1954 at least partially overlap each other; Thus, when imaging the second stack 1924, the second stack moiré pattern 19 It will be appreciated that the second 60 can be seen as known in the art. Stacked Moire Patterns of the 1960s, Pitch "24 Hebrew Letters" Characterized by pitch "Hebrew 25" is the second stack multiplication factor q, the pitch "26 Hebrew letters" , and pitch "27 Hebrew letters" is a function of .

number

[0270] As can be seen particularly in FIG. 19D, the third stack 1926, together with the first layer 1902, The third stack includes a first periodic structure (S3P1) 1962 formed on the first periodic structure (S3P1) 1962. 1962 along one of the third stack axes 1936, "28 Hebrew letters" Preferably, the S3P1 pitch is "Hebrew Letter 29" is multiplied by the third stack multiplication factor, designated as r, to produce the S1P1 pitch. "30 Hebrew letters" The third stack multiplication factor r can be any positive number. The third stack 1926 is a second layer of the third stack formed with the fourth layer 1908. The third stack axis is a third stack axis. Along with another one from 1936, "Hebrew Letter 31" Preferably, the S3P2 pitch is "Hebrew Letter 32" is the S1P2 pitch by the third stack multiplication factor r "Hebrew letter 33" It is related to the S3P2 pitch. "Hebrew Letter 34" S1P2 pitch "Hebrew Letter 35" The third stack multiplication factor r, which relates to the S3P1 pitch "Hebrew Letter 36" S1P1 pitch "Hebrew letter 37" It will be appreciated that the third stack multiplication factor r relating In one embodiment, the value of r is 1, and therefore the S3P1 pitch "Hebrew letter 38" is S1P1 pitch "Hebrew letter 39" The pitch is the same as S3P2 "40 Hebrew Letters" is S1P2 pitch "Hebrew Letter 41" is identical to

[0271] S3P1 1962 and S3P2 1964 at least partially overlap each other, Thus, when imaging the third stack 1926, the third stack moiré pattern 19 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. Stacked Moire Patterns of the 1970s, Pitch "Hebrew Letter 42" Characterized by pitch "Hebrew letter 43" is the third stack multiplication factor r, the pitch "Hebrew Letter 44" , and pitch "Hebrew Letter 45" is a function of .

number

[0272] Misalignment between any two of layers 1904, 1906, and 1908 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. Pitch "Hebrew Letter 46" , "Hebrew Letter 47" , "48 Hebrew letters" , "Hebrew Letter 49" , "50 Hebrew Letters" , and "Hebrew Letter 51" The optical displacement measurement tool used to generate an image of the target 1900 However, it is not necessary that the pitch "Hebrew Letter 52" , "Hebrew letter 53" , and "Hebrew letter 54" Each of the targets 1900 is measured by a misalignment measurement tool used to generate an image of the target 1900. It is preferably optically resolvable.

[0273] Referring now to FIGS. 20A-20D, FIGS. 20A-20D show a multi-layer moire target of the present invention. 20A-20D are simplified diagrams of another embodiment of a target 2000. , and z-axes, and these three The dimensions are called the xy plane, the xz plane, and the yz plane, respectively. 20B, 20C, and 20D show planes parallel to the xz plane. I want to be loved.

[0274] Target 2000 is a substitute for target 1900 described herein above with reference to Figures 19A-19D. This is an example of a permutation, and additional permutations are described later in this specification with reference to Figures 34-39. Note that the target 2000 is preferably formed on a semiconductor device wafer and is preferably or on a semiconductor device wafer, at least a first layer 2002, a second layer 2004, a third layer 2005, The first layer 2002, the second layer 2003, and the fourth layer 2008 are formed. Each of the first layer 2004, the third layer 2006, and the fourth layer 2008 is substantially planar and parallel to the xy plane. It will be understood that the first layer 2002, the second layer 2004, the third layer 2006, and the third layer 2008 define a surface. 2006, and the fourth layer 2008 may be adjacent layers, but are not necessarily adjacent layers. Preferably, the first layer 2002, the second layer 2004, the third layer 2006, and Any material between the first and fourth layers 2008 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIGS. 20A-20D, the first layer 2002 has a second layer 20 2004, a third layer 2006, and a fourth layer 2008, and the second layer 2004 is located below the Located below the third layer 2006 and the fourth layer 2008, the fourth layer 2008 is 2002, a second layer 2004, and a third layer 2006. However, layers 20 02, 2004, 2006, and 2008 are aligned along the z-axis with respect to each other in any suitable manner. It will be appreciated that the elements may be arranged in any order.

[0275] In addition, in one embodiment of the present invention, the second layer 2004 and the third layer 2006 All of the structures shown as formed can be formed with layer 2004. In such an embodiment, no portion of the target 2000 is formed with the layer 2006. Such an embodiment may be described later in this specification with reference to Figures 21A-21C. This is particularly useful for calibration. Additionally, in another embodiment of the present invention, the second layer 2004 and All of the structures shown formed with layers 2004 and 2008 are shown in FIG. In such an embodiment, any portion of the target 2000 may be formed with Such an embodiment is not formed with layer 2008. See Figures 21A-21C. This is particularly useful for calibration, as described later in this specification. In the illustrative embodiment, the semiconductor laser is shown formed with a third layer 2006 and a fourth layer 2008. All of the structures shown can be formed together with layer 2006. In such an embodiment, , no portion of target 2000 is formed with layer 2008. Such an embodiment may This is particularly useful for calibration, as described later in this specification with reference to Figures 21A-21C. do.

[0276] As can be seen particularly in FIG. 20A, the target 2000 is divided into four target halves 2012, 201 4, 2016, and 2018. In the embodiment shown in FIG. 20A, the target 4 halves 201 The rotation directions in the xy plane of each of 2, 2014, 2016, and 2018 are preferably , 2012, 2014, 2016, and 201 are the other halves of the targets, which are integer multiples of 90°. 8 are different from each other in the xy plane. In addition, the target 2000 is preferably It is characterized by rotational symmetry in either the x or y direction or both. According to a preferred embodiment of the invention, when target 2000 is in a superimposed state, target 2 The whole of 000 is bounded by a single symmetric point in the x direction and a single symmetric point in the y direction. However, even in such an embodiment, the alignment of the stator and the stator are not affected by the alignment of the stator and the stator. At times, various elements of the target 2000 are characterized by unique points of symmetry.

[0277] Each of the four target halves 2012, 2014, 2016, and 2018 has a first periodic structure stack 2022, a second periodic structure stack 2024, and a third periodic structure stack 2 026. The first stack 2022, the second stack 2024, and the third stack Each of the blocks 2026 includes one or more periodic structures, each of which has a pitch. Generally, the first stack 2022, the second stack 2024, and the third stack 202 20A to 20D, the first stack 202 2 is the center of the target 2000 from the second stack 2024 and the third stack 2026. 2, the third stack 2026 is shown positioned adjacent to the first stack 20 22 and a second stack 2024 are shown positioned near the edge of the target 2000. However, the first stack 2022, the second stack 2024, and the third stack 2025 are The stacks 2026 may be arranged in any suitable arrangement relative to each other in the xy plane. can.

[0278] In the embodiment shown in FIGS. 20A to 20D, a first stack 2022, a second stack 2 024, and the periodic structure of the third stack 2026 are each formed of a plurality of lines and spaces. Although shown in a completed state, in other embodiments of the present invention, the first stack 2022, The periodic structures of the second stack 2024 and the third stack 2026 may be of any suitable period. It will be appreciated that the first stack 2022, the second stack 2023, and the third stack 2024 may be formed from a single feature. The periodic structure formed within the stack 2024 and the third stack 2026 It will be further understood that features may be formed from substructures. 2022, the second stack 2024, and the third stack 2026. The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. It is.

[0279] As seen in Figure 20A, the four halves 2012, 2014, 2016, and 2018 A plurality of first shafts 20 intersect the first stack 2022 and are positioned therein. 32 and intersects with the second stack 2024 and is located therein. A second plane 2033 including a plurality of second axes 2034 intersects with the third stack 2026. , and a third plane 2035 including a plurality of third axes 2036 located therein. The first stack 2 in each of the 4 halves 2012, 2014, 2016, and 2018 Depending on the orientation of the first stack 2022, the second stack 2024, and the third stack 2026, Each of the first plane 2031, the second plane 2033, and the third plane 2035 is a plane parallel to the xz plane. or the yz plane, and a first axis 2032, a second axis 2034, and a third axis 2036 are parallel to the respective x-axis or y-axis. 4 halves 2012, 2014, 20 16, and 2018, a first plane 2031, a second plane 2033, and It will be appreciated that the first and third planes 2035 are all parallel to one another.

[0280] As can be seen particularly in FIG. 20B, the first stack 2022 includes a first layer 2002. The first stack includes a first periodic structure (S1P1) 2042 formed in the first stack, and S1P1 2042 along one of the first stack axes 2032 "Hebrew Letter 55" The first stack 2022 has a pitch designated as S1P1. 4. The second periodic structure (S1P2) 2044 of the first stack is formed with and S1P2 2044 is aligned along another of the first stack axes 2032. "Hebrew letter 56" The pitch is designated as S1P2.

[0281] S1P1 2042 and S1P2 2044 at least partially overlap each other; Thus, when imaging the first stack 2022, the first stack moiré pattern 20 It will be appreciated that the first 50 can be seen. The stacked moire patterns are 2050 in pitch "Hebrew letter 57" Characterized by pitch "Hebrew letter 58" is the pitch as shown in Equation 44. "Hebrew letter 59" and "60 Hebrew letters" is a function of .

number

[0282] As can be seen particularly in FIG. 20C, the second stack 2024 is formed together with the first layer 2002. The first periodic structure (S2P1) 2052 of the second stack is formed on the first periodic structure (S2P1) 2052 of the second stack. 2052 along one of the second stack axes 2034 "Hebrew letter 61" Preferably, the S2P1 pitch is "Hebrew Letter 62" is multiplied by the second stack multiplication factor, designated as s, to produce the S1P1 pitch. "Hebrew letter 63" The second stack multiplication factor s can be any positive number. The second stack 2024 is a second layer of the second stack formed with the third layer 2006. The second stack axis is a second stack axis. Along with another one of 2034, "Hebrew Letter 64" Preferably, the S2P2 pitch is "Hebrew Letter 65" is the S1P2 pitch by the second stack multiplication factor s "Hebrew letter 66" It is related to the S2P2 pitch. "Hebrew letter 67" S1P2 pitch "Hebrew letter 68" The second stack multiplication factor s, which relates to the S2P1 pitch "Hebrew letter 69" S1P1 pitch "70 Hebrew Letters" It will be appreciated that the second stack multiplication factor s relating In one embodiment, the value of s is 1, and therefore the S2P1 pitch "Hebrew Letter 71" is S1P1 pitch "72 Hebrew letters" The pitch is the same as S2P2. "Hebrew letter 73" is S1P2 pitch "Hebrew Letter 74" is identical to

[0283] S2P1 2052 and S2P2 2054 at least partially overlap each other; Thus, when imaging the second stack 2024, the second stack moiré pattern 20 It will be appreciated that the second 60 can be seen as known in the art. The stacked moire pattern of 2060 is pitch "75 Hebrew letters" Characterized by pitch "Hebrew Letter 76" is the second stack multiplication factor q, the pitch "Hebrew Letter 77" , and pitch "Hebrew Letter 78" is a function of .

number

[0284] As can be seen particularly in FIG. 20D, the third stack 2026, together with the first layer 2002, The third stack includes a first periodic structure (S3P1) 2062 formed on the first periodic structure (S3P1) 2062. 2062 along one of the third stack axes 2036 "Hebrew letter 79" Preferably, the S3P1 pitch is "80 Hebrew Letters" is multiplied by the third stack multiplication factor, designated as t, to produce the S1P1 pitch. "Hebrew Letter 81" The third stack multiplication factor t can be any positive number. The third stack 2026 is formed with the fourth layer 2008. The third stack axis is a third stack axis. Along with another one of 2036, "Hebrew Letter 82" Preferably, the S3P2 pitch is "Hebrew letter 83" is the S1P2 pitch by the third stack multiplication factor t "Hebrew Letter 84" It is related to the S3P2 pitch. "Hebrew Letter 85" S1P2 pitch "Hebrew letter 86" The third stack multiplication factor t, which relates to the S3P1 pitch "Hebrew letter 87" S1P1 pitch "Hebrew letter 88" It will be appreciated that the third stack multiplication factor t relating In one embodiment, the value of t is 1, and therefore the S3P1 pitch "Hebrew letter 89" is S1P1 pitch "90 Hebrew letters" The pitch is the same as S3P2 "Hebrew Letter 91" is S1P2 pitch "Hebrew Letter 91" is identical to

[0285] S3P1 2062 and S3P2 2064 at least partially overlap each other; Thus, when imaging the third stack 2026, the third stack moiré pattern 20 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stacked moire pattern of 2070 is pitch "Hebrew Letter 92" Characterized by pitch "Hebrew letter 93" is the third stack multiplication factor t, the pitch "Hebrew Letter 94" , and pitch "Hebrew Letter 95" is a function of .

number

[0286] Misalignment between any two of layers 2004, 2006, and 2008 is preferred. Alternatively, an imaging displacement metrology tool with adjustable polarization, wavelength, and numerical aperture settings may be used. An example of a suitable imaging displacement measurement tool is the Archer™ available from KLA Corporation of Rupita 700. Pitch "Hebrew Letter 96" , "Hebrew Letter 97" , "Hebrew Letter 98" , "Hebrew letter 99" , "100 Hebrew Letters" , and "Hebrew Alphabet 101" The optical displacement measurement tool used to generate the image of the target 2000 However, it is not necessary that the pitch "Hebrew Letter 102" , "Hebrew Letter 103" , and "Hebrew Letter 104" Each of the targets is measured by a misalignment measurement tool used to generate an image of the target 2000. It is preferably optically resolvable.

[0287] Referring now to FIG. 21A, FIG. 21A illustrates a multi-layer semiconductor formed by a target 2100. Layers 1904, 1906, and 1908 of the device wafer (FIGS. 19A-19D), 20A-20D ) 2104 , 2006 , and 2008 . , the third layer 2106, and the fourth layer 2108 in either the x-direction or the y-direction. In the row direction, a target 1900 (FIGS. 19A-19D) including a first layer 1902 or The first layer 2102 of the target 2000 (FIGS. 20A-20D) may be FIG. 21 is a simplified diagram showing a preferred method for calculating misregistration using a multi-layer moire target 2100 including 21B and 21C, the flow chart of FIG. 1C is a simplified illustration of a first and second embodiment of a portion of the method of FIG. 21A, respectively. FIG.

[0288] When using target 2000 (FIGS. 20A-20D), please refer to FIGS. 21A-21C. The method described uses 1 It will be appreciated that the above steps may be performed only once, but typically the steps described in FIGS. 21A-21C are performed once. The method described above is performed twice to calculate the displacement in each of the x and y directions. When using the target 1900 (FIGS. 19A to 19D), the first stack shaft 193 2, the second stack axis 1934, and the third stack axis 1936 are parallel to one another. It will also be appreciated that misregistration can be calculated only in one direction.

[0289] As seen in the first step 2109, a direction in which to measure the misalignment is selected. When using the target 1900 in the manner of FIGS. 21A and 21B, the direction in which the displacement is measured is , a first stack axis 1932, a second stack axis 1934, and a third stack axis 19 21A and 21B are automatically selected so that the direction of the arrows 36 is parallel. When using target 2000, the structure of the four halves 2014 and 2018 is parallel to the x-axis. 2012 and 2016 are used to measure the misalignment in the four halves of the structure. is used to measure the displacement in a direction parallel to the y-axis.

[0290] Preferably, in the next step 2110, the image of the target 2100 is captured using adjustable polarization, wavelength, The image is generated using an imaging position measurement tool having a setting of the number of apertures and a numerical aperture. An example of an image misalignment measurement tool is available from KLA Corp., Milpitas, Calif., USA. The pitch is Archer 700, available from Oration. "Hebrew Letter 105" , "Hebrew letter 106" , "Hebrew letter 107" , "Hebrew Letter 108" , "Hebrew Letter 109" , "Hebrew Letter 110" , "Hebrew Letter 111" , "Hebrew Letter 112" , "Hebrew letter 113" , "Hebrew letter 114" , "Hebrew Letter 115" , and "Hebrew letter 116" is optically measured by a position measurement tool used to generate an image of the target 2100. Note that it is not necessary for the pitch "Hebrew letter 117" , "Hebrew letter 118" , "Hebrew letter 119" , "120 Hebrew letters" , "Hebrew Letter 121" , and "Hebrew alphabet 122" Each of the three is determined by the displacement measurement tool used to generate the image of the target 2100. It is preferably optically resolvable.

[0291] In the next step 2111, a first region of interest is generated, as seen in FIG. 21B and FIG. 21C. 2112, a second region of interest 2114, and a third region of interest 2116 are In the quadrant selected in 9, a first stack 1922, a second stack 1924, and and the third stack 1926 (FIGS. 19A to 19D) or the first stack 2022, a second stack 2024, and a third stack 2026 (FIGS. 20A to 20D), and so on. The first stack 2122, the second stack 2124, and the third stack 21 26. As can be seen in the illustrated embodiment of FIG. 21B and FIG. 21C, As shown, the first region of interest 2112, the second region of interest 2114, and the third region of interest 211 6 is preferably a first region of interest 2112 located entirely within the first stack 2122. As shown in FIG. 1, each of the first stack 2122, the second stack 2124, and The first region of interest 2112, the second region of interest 2113, and the third stack 2126 are entirely located in each of the stacks. The first region of interest 2114 and the third region of interest 2116 are respectively located in the second stack 21 24 and the third stack 2126. As shown, each of the first stack 2122, the second stack 2124, and It will be appreciated that the third stack 2126 may extend beyond the third stack 2126. Regions of interest 2112, 2114, and 2116 shown in FIG. 21C are representative regions of interest. It will be further appreciated that other suitable regions of interest may also be selected in step 2111. Let it be.

[0292] In the next step 2131, as seen in FIG. 21B and FIG. 21C, The location of symmetric points 2132 between all instances of the first region of interest 2112 selected in 1 In the next step 2133, as seen in Figures 21B and 21C, Symmetry between all instances of the second region of interest 2114 selected in step 2111 The location of point 2134 is calculated. In the next step 2135, the location of point 2134 is calculated as shown in FIG. 2116 selected in step 2111. The location of the symmetric point 2136 between the chests is calculated.

[0293] In the next step 2137, the step 21 in the direction selected in step 2109 is The location of the symmetric point 2132 of the first one or more regions of interest 2112 identified in step 31 and 2133 and the location of the symmetric point 2134 of the second one or more regions of interest 2114 identified in step 2133. The distance between the two is calculated. The distance found in step 2137 is "Hebrew alphabet 123" The gain is divided by "Hebrew alphabet 124" For target 1900, the pitch is "Hebrew Letter 125" and pitch "Hebrew letter 126" is a function of .

number

number

[0294] In the next step 2139, the step 21 in the direction selected in step 2109 is The location of the symmetric point 2134 of the second one or more regions of interest 2114 identified in step 33 and and the location of the symmetric point 2136 of the third one or more regions of interest 2116 identified in step 2135. The distance between the two points is calculated. The distance found in step 2139 is "Hebrew letter 134" The gain is divided by "Hebrew letter 135" For target 1900, the pitch is "Hebrew letter 136" and pitch "Hebrew letter 137" is a function of .

number

number

[0295] In the next step 2141, the step 21 in the direction selected in step 2109 is The location of the symmetric point 2132 of the first one or more regions of interest 2112 identified in step 31 and and the location of the symmetric point 2136 of the third one or more regions of interest 2116 identified in step 2135. The distance between the two is calculated. The distance found in step 2141 is "Hebrew Letter 145" The gain is divided by "Hebrew letter 146" For target 1900, the pitch is "Hebrew letter 147" and pitch "Hebrew Letter 148" is a function of .

number

number

[0296] Preferably, it is shown formed with second layer 2104 and third layer 2106. In the embodiment described hereinabove, all of the structures shown are formed with layer 2104. The method described herein above with reference to Figures 21A to 21D may include, in step 2139, Calculating the difference between the misalignment value measured in step 2141 and the misalignment value reported in step 2142; The difference between the misalignment values ​​reported in steps 2139 and 2141 is calculated using the This is useful for calibrating the position deviation measurement tool used in the methods of Figs. 1A to 21D.

[0297] Additionally, it is shown formed with a second layer 2104 and a fourth layer 2108. In the embodiment described herein above, where all of the structures are formed with layer 2104, The method described herein above with reference to FIGS. 21A-21D includes the steps of: Calculate and report the difference between the misalignment value measured and the misalignment value reported in step 2139. The difference between the misregistration values ​​reported in steps 2137 and 2139 is calculated using the formula shown in FIG. ~ Useful in calibrating the displacement metrology tool used in the method of FIG. 21D.

[0298] Further, it is shown formed with a third layer 2106 and a fourth layer 2108. In the embodiment described herein above, where all of the structures are formed with layer 2106, The method described herein above with reference to FIGS. 21A-21D includes the steps of: Calculate and report the difference between the misalignment value measured and the misalignment value reported in step 2141. The difference between the misregistration values ​​reported in steps 2137 and 2141 is calculated using the formula shown in FIG. ~ Useful in calibrating the displacement metrology tool used in the method of FIG. 21D.

[0299] In one embodiment of the present invention, where layer 2108 is located below layer 2106, FIGS. The relevant portion of the method described herein above with reference to layers 2102, 2104, and 210 It will be appreciated that only step 8 may be used and performed prior to forming layer 2106. .

[0300] Referring now to FIGS. 22A-22E, which show a multi-layer moire target of the present invention. 22A-22E are simplified diagrams of another embodiment of a target 2200. , and z-axes, and these three The dimensions are called the xy plane, the xz plane, and the yz plane, respectively. 22B, 22C, 22D, and 22E show planes parallel to the xz plane. Please note that.

[0301] The target 2200 is preferably formed on a semiconductor device wafer and is preferably On the device wafer, at least a first layer 2202, a second layer 2204, a third layer 2206 , and a fourth layer 2208 are formed. The layer 2206 and the fourth layer 2208 each define a substantially planar surface parallel to the xy plane. It will be understood that the first layer 2202, the second layer 2204, the third layer 2206, and The first and fourth layers 2208 may, but need not, be adjacent layers. Preferably, the first layer 2202, the second layer 2204, the third layer 2206, and the fourth layer 2208 are Any material between 208 is at least partially transparent to electromagnetic radiation. In the embodiment shown in Figures 2A-22E, a first layer 2202 is formed from a second layer 2204, a third layer 2205, and a 2206 and a fourth layer 2208, and the second layer 2204 is located below the third layer 220 6 and a fourth layer 2208, which is a layer that is formed by stacking the first layer 2202, the second layer 2203, and the third layer 2204. 2204, and the third layer 2206. However, the layers 2202, 2204 , 2206, and 2208 may be arranged in any suitable order along the z-axis relative to one another. It will be understood that it is possible.

[0302] Additionally, in one embodiment of the present invention, the first layer 2202 and the third layer 2206, All of the structures shown as formed can be formed with layer 2202. In such an embodiment, no portion of the target 2200 is formed with the layer 2206. Such an embodiment may be described later in this specification with reference to Figures 24A-24D. This is particularly useful for calibration. In addition, in another embodiment of the present invention, the first layer 2202 and All of the structures shown formed with the fourth layer 2208 are formed from layers 2202 and 2204. In such an embodiment, any portion of the target 2200 may be formed with Such an embodiment is shown in FIG. 24A-24D. As will be described later in this specification, this is particularly useful for calibration. In this embodiment, the insulating layer 2202 is shown formed with a second layer 2204 and a fourth layer 2208. All of the structures described above may be formed together with layer 2204. In such an embodiment, No portion of the target 2200 is formed with the layer 2208. Such an embodiment may include This is particularly useful for calibration, as described later in this specification with reference to Figures 24A-24D. .

[0303] 22A-22E show one possible arrangement of targets 2200, in accordance with another embodiment of the present invention. In some embodiments, it will be appreciated that the target 2200 may include additional structures. For example, As will be described later in this specification with reference to Figures 23A-23E and Figures 34-39, a preferred A target may include multiple instances of the structures shown in Figures 22A-22E. Multiple instances of can be arranged in a variety of ways.

[0304] Preferably, the target 2200 includes a first periodic structure stack 2222, a second periodic structure stack 2223, and a 2224, a third periodic structure stack 2226, and a fourth periodic structure stack 222 8. A first stack 2222, a second stack 2224, and a third stack 2226 , and the fourth stack 2228 each include one or more periodic structures, each periodic structure having a pitch. Preferably, the first stack 2222, the second stack 2224, the third stack 2225, None of the stacks 2226 and the fourth stack 2228 overlap each other. .

[0305] In FIG. 22A to FIG. 22E, a first stack 2222, a second stack 2224, a third stack 2225, and a Each of the periodic structures of the stack 2226 and the fourth stack 2228 includes a plurality of lines and Although shown formed from a space, in other embodiments of the invention, the first stack 2222, a second stack 2224, a third stack 2226, and a fourth stack 2227. It will be appreciated that the periodic structure of 228 may be formed from any suitable periodic features. The first stack 2222, the second stack 2224, the third stack 2226, and The periodic features forming the periodic structure contained within the fourth stack 2228 are formed from substructures. It will be further understood that the first stack 2222, the second stack Each of the periodic structures of the first stack 2224, the third stack 2226, and the fourth stack 2228 The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. m.

[0306] A first xz plane 2231 intersects with the first stack 2222. 32 is located in the first xz plane 2231 and is parallel to the x-axis. 3 intersects with the second stack 2224. A plurality of second axes 2234 are aligned in a second xz plane. 2233 and is parallel to the x-axis. A third xz plane 2235 is located within the third stack 2 226. A number of third axes 2236 lie in a third xz plane 2235 and A fourth xz plane 2237 intersects with the fourth stack 2228. A fourth axis 2238 lies in a fourth xz plane 2237 and is parallel to the x-axis.

[0307] As can be particularly seen in FIG. 22B, according to a preferred embodiment of the present invention, the first stack 2222 is a first periodic structure (S 1P1) 2242, where S1P1 2242 is one of the first stack shafts 2232. Along the lines of "Hebrew letter 156" Preferably, the first stack 2222 has a pitch designated as S1P1. The second periodic structure (S1P2) 224 of the first stack is formed with the second layer 2204. 4, and S1P2 2244 is connected to another of the first stack shafts 2232. Along "Hebrew letter 157" The pitch is designated as S1P2.

[0308] S1P1 2242 and S1P2 2244 at least partially overlap each other; Thus, when imaging the first stack 2222, the first stack moiré pattern 22 It will be appreciated that the first 50 can be seen. The stacked moire pattern has a pitch of 2250 "Hebrew letter 158" Characterized by pitch "Hebrew letter 159" is the pitch as shown in Equation 50. "Hebrew Letters 160" and "Hebrew Letter 161" is a function of .

number

[0309] In another embodiment of the present invention, the first stack 2222 includes periodic structures 2242 and 22 44, when imaging the first stack 2222, a moiré pattern I can't see 2250.

[0310] As can be seen particularly in FIG. 22C, in accordance with a preferred embodiment of the present invention, the second stack 2224 is a first periodic structure (S 2P1) 2252, where S2P1 2252 is one of the second stack shafts 2234. Along the lines of "Hebrew Letter 162" Preferably, the second stack 2224 has a pitch designated as S2P1. A second periodic structure (S2P2) 225 of a second stack formed with the second layer 2204. 4, and S2P2 2254 is connected to another of the second stack shafts 2234. Along "Hebrew letter 163" The pitch is designated as S2P2.

[0311] S2P1 2252 and S2P2 2254 at least partially overlap each other; Thus, when imaging the second stack 2224, the second stack moiré pattern 22 It will be appreciated that the second 60 can be seen as known in the art. The stacked moire pattern of 2260 has a pitch "Hebrew letter 164" Characterized by pitch "Hebrew Letter 165" is the pitch as shown in Equation 51. "Hebrew letter 166" and pitch "Hebrew letter 167" is a function of .

number

[0312] As can be seen particularly in FIG. 22D, in accordance with a preferred embodiment of the present invention, the third stack 2226 is a first periodic structure (S 3P1) 2262, where S3P1 2262 is one of the third stack axes 2236. Along the lines of "Hebrew letter 168" Preferably, the S3P1 pitch is "Hebrew letter 169" is multiplied by the third stack multiplication factor, specified as u, to produce the S2P2 pitch "170 Hebrew letters" The third stack multiplication factor u can be any positive number. Preferably, the third stack 2226 is a third stack formed with the third layer 2206. The second periodic structure (S3P2) 2264 of the block further includes a third periodic structure (S3P2) 2264 of the block. along another of the stack axes 2236, "Hebrew Letter 171" Preferably, the S3P2 pitch is "Hebrew Letter 172" is the S2P1 pitch by the third stack multiplication factor u "Hebrew letter 173" It is related to the S3P2 pitch. "Hebrew letter 174" The S2P1 pitch "Hebrew Letter 175" The third stack multiplication factor u, which relates to the S3P1 pitch "Hebrew letter 176" S2P2 pitch "Hebrew letter 177" It will be appreciated that the third stack multiplication factor u relating In one embodiment, the value of u is 1, and therefore the S3P1 pitch "Hebrew letter 178" is S2P2 pitch "Hebrew Letter 179" The pitch is the same as S3P2 "Hebrew Alphabet 180" is S2P1 pitch "Hebrew Letter 181" is identical to

[0313] S3P1 2262 and S3P2 2264 at least partially overlap each other; Thus, when imaging the third stack 2226, the third stack moiré pattern 22 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stacked moire pattern of 2270 is pitch "Hebrew Letter 182" Characterized by pitch "Hebrew letter 183" is the third stack multiplication factor u, the pitch "Hebrew Letter 184" , and pitch "Hebrew Letter 185" is a function of .

number

[0314] As can be seen particularly in FIG. 22E, in accordance with a preferred embodiment of the present invention, the fourth stack 2228 is a first periodic structure (S S4P1 2272 is one of the fourth stack axes 2238. Along the lines of "Hebrew letter 186" Preferably, the S4P1 pitch is "Hebrew letter 187" is multiplied by the fourth stack multiplication factor, designated as v, to produce the S2P1 pitch. "Hebrew letter 188" The fourth stack multiplication factor v can be any positive number. Preferably, the fourth stack 2228 is a fourth stack formed with the fourth layer 2208. The second periodic structure (S4P2) 2274 of the block further includes a fourth periodic structure (S4P2) 2274 of the block. Along another of the stack axes 2238, "Hebrew letter 189" Preferably, the S4P2 pitch is "Hebrew Letter 190" is the S2P2 pitch by the fourth stack multiplication factor v "Hebrew Letter 191" It is related to S4P2 pitch. "Hebrew Letter 192" S2P2 pitch "Hebrew letter 193" The fourth stack multiplication factor v, which relates to the S4P1 pitch "Hebrew Letter 194" The S2P1 pitch "Hebrew Letter 195" It will be appreciated that the fourth stack multiplication factor v relating In one embodiment, the value of v is 1, and therefore the S4P1 pitch "Hebrew letter 196" is S2P1 pitch "Hebrew letter 197" It is the same as S4P2 pitch "Hebrew letter 198" is S2P2 pitch "Hebrew Letter 199" is identical to

[0315] S4P1 2272 and S4P2 2274 at least partially overlap each other; Thus, when the fourth stack 2228 is imaged, the fourth stack moiré pattern 22 It will be appreciated that the fourth embodiment may be viewed as a single block, as known in the art. The stacked moire pattern of 2280 is "200 Hebrew Letters" Characterized by pitch "Hebrew Alphabet 201" is the fourth stack multiplication factor v, the pitch, as shown in Equation 53. "Hebrew Alphabet 202" , and pitch "Hebrew Alphabet 203" is a function of .

number

[0316] Between any two of the layers 2202, 2204, 2206, and 2208 This is preferably an imaging dislocation meter with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Arche is commercially available from KLA Corporation, Milpitas, Maryland. r(trademark) 700. Pitch "Hebrew Alphabet 204" , "Hebrew Letter 205" , "Hebrew Letter 206" , "Hebrew Letter 207" , "Hebrew Letter 208" , "Hebrew Letter 209" , "210 Hebrew Letters" , and "Hebrew Alphabet 211" is optically measured by a position measurement tool used to generate an image of the target 2200. However, it is not necessary that the pitch "Hebrew alphabet 212" , "Hebrew alphabet 213" , "Hebrew alphabet 214" , and "Hebrew Letter 215" Each of the following is determined by the misalignment measurement tool used to generate the image of the target 2200: It is preferably optically resolvable.

[0317] Referring now to FIGS. 23A-23E, which show a multi-layer moire target of the present invention. 23A-23E are simplified diagrams of another embodiment of a target 2300. , and z-axes, and these three The dimensions are called the xy plane, the xz plane, and the yz plane, respectively. 23B, 23C, 23D, and 23E show planes parallel to the xz plane. Please note that.

[0318] Target 2300 is a substitute for target 2200 described herein above with reference to Figures 22A-22E. This is an example of a permutation, and additional permutations are described later in this specification with reference to Figures 34-39. Note that the target 2300 is preferably formed on a semiconductor device wafer and is preferably or on a semiconductor device wafer, at least a first layer 2302, a second layer 2304, a third layer 2305, The first layer 2302, the second layer 2303, and the fourth layer 2308 are formed. Each of the third layer 2304, the third layer 2306, and the fourth layer 2308 is substantially planar and parallel to the xy plane. It will be understood that the first layer 2302, the second layer 2304, the third layer 2305 and the third layer 2306 define a surface. 2306, and the fourth layer 2308 may be adjacent layers, but are not necessarily adjacent. Preferably, the first layer 2302, the second layer 2304, the third layer 2306, and Any material between the first and fourth layers 2308 is at least partially transparent to electromagnetic radiation. In the embodiment shown in FIGS. 23A to 23E, the first layer 2302 has a second layer 23 2304, third layer 2306, and fourth layer 2308, and second layer 2304 is Located below the third layer 2306 and the fourth layer 2308, the fourth layer 2308 is 2302, a second layer 2304, and a third layer 2306. However, layer 23 02, 2304, 2306, and 2308 are aligned along the z-axis with respect to each other in any suitable manner. It will be appreciated that the elements may be arranged in any order.

[0319] Additionally, in one embodiment of the present invention, the first layer 2302 and the third layer 2306, All of the structures shown as formed can be formed with layer 2302 In such an embodiment, no portion of the target 2300 is formed with the layer 2306. Such an embodiment may be described later in this specification with reference to Figures 24A-24D. This is particularly useful for calibration. In addition, in another embodiment of the present invention, the first layer 2302 and All of the structures shown formed with layers 2302 and 2308 are shown in FIG. In such an embodiment, any portion of the target 2300 may be formed with Such an embodiment is not formed with layer 2308. See Figures 24A-24D. This is particularly useful for calibration, as described later in this specification. In the embodiment shown, the second layer 2304 and the fourth layer 2308 are formed. All of the structures shown may be formed together with layer 2304. In such an embodiment, 2308. In such an embodiment, no portion of the target 2300 is formed with the layer 2308. This is particularly useful for calibration, as described later in this specification with reference to Figures 24A-24D. do.

[0320] As can be seen particularly in FIG. 23A, the target 2300 is divided into four target halves 2312, 2313, 2314, 2315, 2316, 2317, 2318, 2319, 2320, 2321, 2322, 2323, 2324, 2325, 2326, 2327, 23 In the embodiment shown in FIG. 23A, the target halves 231 The rotation directions of each of 2, 2314, 2316, and 2318 in the xy plane are preferably , 2312, 2314, 2316, and 231 are the other halves of the targets, which are integer multiples of 90°. 8 are different from each other in the xy plane. In addition, the target 2300 is preferably It is characterized by rotational symmetry in either the x or y direction or both. According to a preferred embodiment of the invention, when target 2300 is in a superimposed state, target 2 The entire 300 is bounded by a single point of symmetry in the x direction and a single point of symmetry in the y direction. However, even in such an embodiment, the alignment of the stator and the stator are not affected by the alignment of the stator and the stator. At times, various elements of the target 2300 are characterized by unique points of symmetry.

[0321] Each of the target halves 2312, 2314, 2316, and 2318 includes a first periodic structure. stack 2322, a second periodic structure stack 2324, and a third periodic structure stack 2326 , and a fourth periodic structure stack 2328. Each of the first stack 2324, the second stack 2326, and the fourth stack 2328 includes one The first stack 23 preferably includes the above periodic structures, each of which has a pitch. 22, a second stack 2324, a third stack 2326, and a fourth stack 232 23A to 23E, the first stack 232 2 includes a second stack 2324, a third stack 2326, and a fourth stack 232 8, the second stack 2300 is shown positioned near the center of the target 2300. 24 is selected from the third stack 2326 and the fourth stack 2328 of the target 2300. The third stack 2326 is shown positioned near the heart, and the third stack 2326 is positioned near the first stack 2326. 322 and a second stack 2324, while positioned near the edge of the target 2300. 23, a fourth stack 2328 is shown having a larger number of targets 2300 than the third stack 2326. However, the first stack 2322, the second stack 2323, The stack 2324, the third stack 2326, and the fourth stack 2328 are mutually The axial alignment elements 11 and 12 may be arranged in any suitable arrangement relative to the xy plane.

[0322] In FIG. 23A to FIG. 23E, a first stack 2322, a second stack 2324, a third stack 2325, and a Each of the periodic structures of the stack 2326 and the fourth stack 2328 includes a plurality of lines and Although shown formed from a space, in other embodiments of the invention, the first stack 2322, a second stack 2324, a third stack 2326, and a fourth stack 2 It will be appreciated that the periodic structure of 328 may be formed from any suitable periodic features. The first stack 2322, the second stack 2324, the third stack 2326, and The periodic features forming the periodic structure contained within the fourth stack 2328 are formed from substructures. It will be further understood that the first stack 2322, the second stack Each of the periodic structures of the first stack 2324, the third stack 2326, and the fourth stack 2328 The pitch is preferably 10 nm to 3000 nm, more preferably 200 nm to 800 nm. m.

[0323] As seen in FIG. 23A, the four halves 2312, 2314, 2316, and 2318 A plurality of first shafts 23 intersect the first stack 2322 and are positioned therein. 32 and intersects with the second stack 2324 and is located within the first plane 2331. A second plane 2333 including a plurality of second axes 2334 intersects with the third stack 2326. a third plane 2335 having a plurality of third axes 2336 located therein; A fourth plane 233 includes a plurality of fourth axes 2338 that intersect the line 2328 and are located therein. 7 are defined. A first stack 2322, a second stack 2324, a third stack 2326, and Depending on the orientation of the fourth stack 2328, a first plane 2331, a second plane 2333, a third plane 2334, a fourth plane 2335, a fourth plane 2336, a fourth plane 2337, a fourth plane 2338, a fourth plane 2339, a fourth plane 2340, a fourth plane 2341, a fourth plane 2342, a fourth plane 2343, a fourth plane 2 Each of the third plane 2335 and the fourth plane 2337 is either the xz plane or the yz plane. a first axis 2332, a second axis 2334, a third axis 2336, and a fourth axis 2338 is parallel to the respective x-axis or y-axis. 16, and 2318, a first plane 2331, a second plane 2333, a third plane 2334, and a It will be appreciated that the first plane 2335, and the fourth plane 2337 are all parallel to one another. cormorant.

[0324] As can be seen particularly in FIG. 23B, in accordance with a preferred embodiment of the present invention, the first stack 2322 is a first periodic structure (S 1P1) 2342, where S1P1 2342 is one of the first stack shafts 2332. Along the lines of "Hebrew letter 216" Preferably, the first stack 2322 has a pitch designated as S1P1. The second periodic structure (S1P2) 234 of the first stack is formed with the second layer 2304. 4, along another one of the first stack axes 2332, "Hebrew Letter 217" The pitch is designated as S1P2.

[0325] S1P1 2342 and S1P2 2344 at least partially overlap each other; Thus, when imaging the first stack 2322, the first stack moiré pattern 23 It will be appreciated that the first 50 can be seen. The stacked moire pattern has a pitch of 2350 "Hebrew Letter 218" Characterized by pitch "Hebrew Letter 219" is the pitch as shown in Equation 54. "220 Hebrew letters" and "Hebrew alphabet 221" is a function of .

number

[0326] In another embodiment of the present invention, the first stack 2322 includes periodic structures 2342 and 23 44, when imaging the first stack 2322, a moiré pattern I can't see 2350.

[0327] As can be seen particularly in FIG. 23C, in accordance with a preferred embodiment of the present invention, the second stack 2324 is a first periodic structure (S 2P1) 2352, along one of the second stack axes 2334, "Hebrew alphabet 222" Preferably, the second stack 2324 has a pitch designated as S2P1. A second periodic structure (S2P2) 235 of a second stack formed with the second layer 2304. 4, along another of the second stack axes 2334, "Hebrew alphabet 223" The pitch is designated as S2P2.

[0328] S2P1 2352 and S2P2 2354 at least partially overlap each other; Thus, when imaging the second stack 2324, the second stack moiré pattern 23 It will be appreciated that the second 60 can be seen as known in the art. The stacked moire pattern of 2360 is pitch "Hebrew alphabet 224" Characterized by pitch "Hebrew alphabet 225" is the pitch as shown in Equation 55. "Hebrew letter 226" and pitch "Hebrew letter 227" is a function of .

number

[0329] As can be seen particularly in FIG. 23D, in accordance with a preferred embodiment of the present invention, the third stack 2326 is a first periodic structure (S 3P1) 2362, where S3P1 2362 is one of the third stack axes 2336. Along the lines of "Hebrew alphabet 228" Preferably, the S3P1 pitch is "Hebrew alphabet 229" is multiplied by the third stack multiplication factor, specified as w, to produce the S2P2 pitch "230 Hebrew letters" The third stack multiplication factor w can be any positive number. Preferably, the third stack 2326 is a third stack formed with the third layer 2306. The second periodic structure (S3P2) 2364 of the block further includes a third periodic structure (S3P2) 2364 of the block. Along another of the stack axes 2336, "Hebrew alphabet 231" Preferably, the S3P2 pitch is "Hebrew alphabet 232" is the S2P1 pitch by the third stack multiplication factor w "Hebrew alphabet 233" It is related to the S3P2 pitch. "Hebrew letter 234" The S2P1 pitch "Hebrew alphabet 235" The third stack multiplication factor w, which relates to the S3P1 pitch "Hebrew letter 236" S2P2 pitch "Hebrew letter 237" It will be appreciated that the third stack multiplication factor w relating In one embodiment, the value of w is 1, thus the S3P1 pitch "Hebrew alphabet 238" is S2P2 pitch "Hebrew letter 239" The pitch is the same as S3P2 "240 Hebrew letters" is S2P1 pitch "Hebrew alphabet 241" is identical to

[0330] S3P1 2362 and S3P2 2364 at least partially overlap each other; Thus, when imaging the third stack 2326, the third stack moiré pattern 23 It will be appreciated that the third embodiment may be viewed as a single-panel display, as known in the art. The stacked moire pattern of 2370 is pitch "Hebrew alphabet 242" Characterized by pitch "Hebrew alphabet 243" is the third stack multiplication factor w, the pitch, as shown in Equation 56. "Hebrew alphabet 244" , and pitch "Hebrew Alphabet 245" is a function of .

number

[0331] As can be seen particularly in FIG. 23E, in accordance with a preferred embodiment of the present invention, the fourth stack 2328 is a first periodic structure (S 4P1) 2372, which is one of the fourth stack axes 2338. Along the lines of "Hebrew alphabet 246" Preferably, the S4P1 pitch is "Hebrew alphabet 247" is multiplied by the fourth stack multiplication factor, designated as x, to produce the S2P1 pitch. "Hebrew alphabet 248" The fourth stack multiplication factor x can be any positive number. Preferably, the fourth stack 2328 is a fourth stack formed with the fourth layer 2308. The second periodic structure (S4P2) 2374 of the block further includes a fourth periodic structure (S4P2) 2374 of the block. Along another of the stack axes 2338, "Hebrew alphabet 249" Preferably, the S4P2 pitch is "250 Hebrew Letters" is the S2P2 pitch multiplied by the fourth stack multiplication factor x "Hebrew Alphabet 251" It is related to S4P2 pitch. "Hebrew Alphabet 252" S2P2 pitch "Hebrew alphabet 253" The fourth stack multiplication factor x, which relates to the S4P1 pitch "Hebrew alphabet 254" The S2P1 pitch "Hebrew alphabet 255" It will be appreciated that the fourth stack multiplication factor x relating In one embodiment, the value of x is 1, and therefore the S4P1 pitch "Hebrew alphabet 256" is S2P1 pitch "Hebrew alphabet 257" It is the same as S4P2 pitch "Hebrew alphabet 258" is S2P2 pitch "Hebrew alphabet 259" is identical to

[0332] S4P1 2372 and S4P2 2374 at least partially overlap each other; Thus, when the fourth stack 2328 is imaged, the fourth stack moiré pattern 23 It will be appreciated that the fourth embodiment may be viewed as a single block, as known in the art. The stacked moire pattern of 2380 is "260 Hebrew Letters" Characterized by pitch "Hebrew Letter 261" is the fourth stack multiplication factor x, the pitch "Hebrew alphabet 262" , and pitch "Hebrew alphabet 263" is a function of .

number

[0333] Between any two of the layers 2302, 2304, 2306, and 2308 This is preferably an imaging dislocation meter with adjustable polarization, wavelength, and numerical aperture settings. An example of a suitable imaging displacement measurement tool is the Arche is commercially available from KLA Corporation, Milpitas, Maryland. r(trademark) 700. Pitch "Hebrew alphabet 264" , "Hebrew Alphabet 265" , "Hebrew alphabet 266" , "Hebrew letter 267" , "Hebrew alphabet 268" , "Hebrew letter 269" , "270 Hebrew letters" , and "Hebrew Letter 271" is optically measured by a misalignment measurement tool used to generate an image of the target 2300. However, it is not necessary that the pitch "Hebrew alphabet 272" , "Hebrew alphabet 273" , "Hebrew alphabet 274" , and "Hebrew alphabet 275" Each of the following is determined by the displacement measurement tool used to generate the image of the target 2300: It is preferably optically resolvable.

[0334] Referring now to FIG. 24A and FIG. 24B, both FIG. 24A and FIG. 24B show target 2 Layers 2202, 2204, 2206 of a multi-layer semiconductor device wafer formed by 400 , and 2208 (FIGS. 22A to 22E), or 2302, 2304, 2306, and The first layer 2402, the second layer 2404, the third layer 2406, and the third layer 2408 (FIGS. 23A-23E) are layer 2406, and a fourth layer 2408 in a direction parallel to either the x-direction or the y-direction. In the example shown in FIG. 22, target 2200 (FIG. 22A to FIG. 22E) or target 2300 (FIG. 23A to FIG. 23E) FIG. 2 illustrates a preferred method for calculating misregistration using a multi-layered moire target 2400 such as 24C and 24D. 24A and 24B show first and second implementations of a portion of the method of FIG. 24A and FIG. 24B, respectively. FIG. 1 is a simplified pictorial representation of a configuration.

[0335] When using target 2300 (FIGS. 23A-23E), please refer to FIGS. 24A-24D. The method described uses 1 ...

Claims

1. 1. A multi-layer moiré target useful for calculating misregistration between at least a first layer, a second layer, and a third layer, the first layer, the second layer, and the third layer being formed on a semiconductor device wafer, the semiconductor device wafer defining an xy plane, the multi-layer moiré target comprising: At least one periodic structure stack group, each of the at least one group comprising: a first periodic structure stack including a first stack first periodic structure (S1P1) formed with at least one of the first layer, the second layer, and the third layer, the S1P1 having an S1P1 pitch along a first axis; a second periodic structure stack including a first periodic structure (S2P1) of a second stack formed with at least one of the first layer, the second layer, and the third layer, the S2P1 having an S2P1 pitch along a second axis; a third periodic structure stack including a first periodic structure (S3P1) of a third stack formed with at least one of the first layer, the second layer, and the third layer, the S3P1 having an S3P1 pitch along a third axis; In the first periodic structure stack, the second periodic structure stack, and the third periodic structure stack, one of the S1P1, the S2P1, and the S3P1 is disposed in a different one of the first layer, the second layer, or the third layer, and the other two of the S1P1, the S2P1, and the S3P1 are disposed in the same one of the first layer, the second layer, or the third layer; the first axis is parallel to either an x-axis or a y-axis when the target is imaged in the xy-plane; the second axis and the third axis are parallel to the first axis when the target is imaged in the xy plane; A multi-layer moire target, wherein at least one of the first, second, and third stacks includes a second periodic structure having a second periodic structure pitch along at least one fourth axis that is parallel to the first axis and coaxial with one of the first axis, the second axis, and the third axis when the target is imaged in the xy plane.

2. 2. The multi-layer moire target of claim 1, the first layer defines a first generally planar surface parallel to the xy plane; the second layer defines a second generally planar surface parallel to the xy plane; the third layer defines a third generally planar surface parallel to the xy plane; the first axis lies in a first plane parallel to one of an xz plane or a yz plane, the one of the xz plane or the yz plane defining, together with the xy plane, a three-dimensional xyz coordinate system; the second axis lies in a second plane parallel to the first plane; the third axis lies in a third plane parallel to the first plane; The at least one fourth axis is located within a respective one of the first plane, the second plane, and the third plane, and is parallel to a respective one of the first axis, the second axis, or the third axis.

3. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the first layer and a second periodic structure (S1P2) of a first stack formed with the second layer, the S1P2 having an S1P2 pitch along a first one of the at least one fourth axis that is coaxial with the first axis when the target is imaged in the xy plane; the second periodic structure stack includes the S2P1 formed with the second layer and a second stack second periodic structure (S2P2) formed with the third layer, the S2P2 having an S2P2 pitch along a second one of the at least one fourth axis that is coaxial with the second axis when the target is imaged in the xy plane; A multi-layer moire target, wherein the third periodic structure stack includes the S3P1 formed with the first layer and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along a third one of the at least one fourth axis when the target is imaged in the xy plane.

4. 4. The multi-layer moire target of claim 3, the S2P1 pitch is related to the S1P2 pitch by a second stack multiplication factor; the S2P2 pitch is related to the S1P1 pitch by the second stack multiplication factor; the S3P1 pitch is related to the S1P1 pitch by a third stack multiplication factor; the S3P2 pitch is related to the S1P2 pitch by the third stack multiplication factor; the second stack multiplication factor is equal to 1 and the third stack multiplication factor is equal to 1 1. A multi-layer moire target comprising:

5. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the first layer, and a second periodic structure (S1P2) of a first stack formed with the second layer, the S1P2 having an S1P2 pitch along a first one of the at least one fourth axis; the second periodic structure stack includes the S2P1 formed with the first layer and a second stack second periodic structure (S2P2) formed with the second layer, the S2P2 having an S2P2 pitch along a second one of the at least one fourth axis; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along a third one of the at least one fourth axis.

6. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the first layer, and a second periodic structure (S1P2) of a first stack formed with the second layer, the S1P2 having an S1P2 pitch along a first one of the at least one fourth axis; the second periodic structure stack includes the S2P1 formed with the first layer and a second stack second periodic structure (S2P2) formed with the second layer, the S2P2 having an S2P2 pitch along a second one of the at least one fourth axis; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the first layer, the S3P2 having an S3P2 pitch along a third one of the at least one fourth axis.

7. 6. The multi-layer moire target of claim 5, the S3P1 pitch is related to the S2P2 pitch by a third stack multiplication factor; the S3P2 pitch is related to the S2P1 pitch by the third stack multiplication factor; 11. A multi-layer moire target, wherein the third stack multiplication factor is equal to 1, the S1P1 pitch is the same as the S2P2 pitch, and the S1P2 pitch is the same as the S2P1 pitch.

8. 6. The multi-layer moire target of claim 5, the S1P1 pitch is the same as the S2P1 pitch; the S1P2 pitch differs from the S1P1 pitch by an additive term; the S2P2 pitch differs from the S1P1 pitch by the additive term; the S3P1 pitch differs from the S1P1 pitch by the additive term; A multi-layer moire target, wherein the S3P2 pitch is the same as the S1P1 pitch.

9. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the second layer; the second periodic structure stack includes the S2P1 formed with the first layer and a second stack second periodic structure (S2P2) formed with the second layer, the S2P2 having an S2P2 pitch along a second one of the at least one fourth axis; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along a third one of the at least one fourth axis.

10. 10. The multi-layer moire target of claim 9, the S2P1 pitch is the same as the S3P2 pitch; A multi-layer moire target, wherein the S2P2 pitch is the same as the S3P1 pitch.

11. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the second layer; the second periodic structure stack includes the S2P1 formed with the first layer; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along the at least one fourth axis.

12. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the first layer; the second periodic structure stack includes the S2P1 formed with the first layer; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the first layer, and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along the at least one fourth axis.

13. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the second layer; the second periodic structure stack includes the S2P1 formed with the first layer; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the first layer, the S3P2 having an S3P2 pitch along the at least one fourth axis.

14. 2. The multi-layer moire target of claim 1, the first periodic structure stack includes the S1P1 formed with the first layer; the second periodic structure stack includes the S2P1 formed with the first layer, and a second stack second periodic structure (S2P2) formed with the second layer, the S2P2 having an S2P2 pitch along a first one of the at least one fourth axis; A multilayer moire target, wherein the third periodic structure stack includes the S3P1 formed with the second layer, and a second periodic structure (S3P2) of a third stack formed with the third layer, the S3P2 having an S3P2 pitch along a second one of the at least one fourth axis.

15. 2. The multi-layer moire target of claim 1, The at least one periodic structure stack group is at least one first periodic stack group, the first axis being parallel to the x-axis when the target is imaged in the xy-plane; and at least one second group of periodic stacks, the first axis being parallel to the y axis when the target is imaged in the xy plane.

16. 16. The multi-layer moire target of claim 15, wherein the at least one first periodic stack group and the at least one second periodic stack group are identical except for their orientation.

17. 16. The multi-layer moire target of claim 15, wherein the target is characterized by mirror image symmetry.

Images