Alignment method, manufacturing method, lithography method, alignment apparatus, and program

Abstract

To provide an alignment method, a manufacturing method, a lithography method, an alignment device, and a program capable of further improving alignment accuracy.SOLUTION: Stacking a first object on which a first array is formed and a second object on which a second array having the first periodic structure is formed, irradiating the stacked first object and second object with light, detecting a signal of the light transmitted through each of the first array of the first object and the second array of the second object, and calculating a positional deviation between the stacked first object and second object based on a plurality of the signals, the first array member is formed on one surface of the first object, and the second array member is formed on one of a front surface and a back surface of the second object, which does not face the first object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an alignment method, a manufacturing method, a lithography method, an alignment apparatus, and a program. [Background technology]

[0002] In recent years, in order to achieve higher performance in semiconductor device fabrication, it has become common to place various device components, such as electrodes, wiring, optical elements, and light-receiving layers, on both sides of a wafer substrate rather than just one side. For example, one development trend in semiconductor light-receiving elements is increasing response speed. To achieve this, it is necessary to reduce the area of ​​the light-receiving layer and reduce the device capacitance. Conventionally, a front-illuminated structure has been used, in which light is directly incident on the light-receiving layer on the substrate. However, to further reduce the area of ​​the light-receiving layer, semiconductor light-receiving elements with a back-illuminated structure have been adopted, in which a lens is formed on the back side of the light-receiving layer of the substrate and light is incident through the lens surface. This requires technology to align and pattern elements on the back side of the substrate with high precision. For example, in the case of the above-mentioned light-receiving element, the light-receiving layer is first formed on the back side of the substrate, and then the lens is formed on the front side, so the optical axes of the light-receiving layer and the lens must be aligned. In other words, to achieve a smaller light-receiving layer, more precise alignment technology is required. In general, semiconductor devices are manufactured by forming elements on both sides of a substrate that is opaque to visible light, such as a silicon substrate or a compound semiconductor substrate, so some ingenuity is required, such as using near-infrared light that penetrates the above materials. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-267682 [Non-patent literature]

[0004] [Non-Patent Document 1] H. Niinomi, S. Harada, T. Hayakawa, et al, “Fluorescence alignment simulation for atomic-scale position adjustment in ultraviolet nanoimprint lithography,” Journal of Vacuum Science & Technology B 35, (2022) 062602; doi: 10.1116 / 6.0002099. Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 provides an alignment technique using moiré fringes, which are generated by superimposing two patterns arranged at different pitches. The patterns used to generate moiré fringes in this method must be arranged at a very small interval, and a high-magnification lens with a high NA (Numerical Aperture) is required for analysis. This results in a shallow depth of focus, making it difficult to focus on the pattern on the back surface of the substrate. In other words, alignment techniques using moiré fringes can result in low alignment accuracy for patterns on the back surface of the substrate.

[0006] In Non-Patent Document 1, the signal used to detect misalignment is detected by fluorescence emission. However, the method in Non-Patent Document 1 can only be applied to substrates that transmit fluorescence wavelengths. Furthermore, since the fluorescence emission signal is obtained from a third object that exists between the two media to be aligned, the method in Non-Patent Document 1 can only be applied to imprint processes.

[0007] As described above, the alignment accuracy of the conventional technology is not sufficient, and there is room for improvement in the alignment accuracy.

[0008] The present invention has been made in consideration of the above circumstances, and one of its objects is to provide an alignment method, a manufacturing method, a lithography method, an alignment apparatus, and a program that can further improve alignment accuracy. [Means for solving the problem]

[0009] A first example of the present invention is an alignment method that includes stacking a first object on which a first array having a first periodic structure is formed and a second object on which a second array having the first periodic structure is formed, irradiating light onto the stacked first object and the second object, detecting a first signal which is a signal of the light that has passed through the first array formed on the first object, detecting a second signal which is a signal of the light that has passed through the second array formed on the second object, and calculating the positional deviation of the stacked first object and the second object based on the first signal and the second signal, wherein the first array is formed on either the first surface or the second surface opposite the first surface of the first object, and the second array is formed on the surface of the second object that does not face the first object, of the third surface or the fourth surface opposite the third surface.

[0010] A second example of the present invention is an alignment method according to the first example, wherein the first object further comprises a third array having a second periodic structure different from the first periodic structure, and the second object further comprises a fourth array having the second periodic structure, and further includes detecting a third signal which is a signal of the light that has passed through the third array formed on the first object, detecting a fourth signal which is a signal of the light that has passed through the fourth array formed on the second object, and calculating the positional misalignment of the stacked first and second objects based on the first signal, the second signal, the third signal, and the fourth signal, wherein the third array is formed on either the first surface or the second surface of the first object, and the fourth array is formed on the surface of the third surface or the fourth surface of the second object that does not face the first object.

[0011] A third example of the present invention is an alignment method according to the first or second example, which further includes adjusting the positions of the stacked first object and the second object based on the calculated positional shift, so that when the first object and the second object are stacked, the first array formed on the first object and the second array formed on the second object are formed so as not to overlap each other.

[0012] A fourth example of the present invention is an alignment method according to the first or second example, wherein the positional deviation between the first object and the second object is calculated using an optical system, the optical system including a stage that adjusts the positions of the first object and the second object in the horizontal direction, the vertical direction, and a rotational direction on the horizontal plane, a light source that is disposed below the stage and irradiates the light, and a camera that is disposed above the stage and detects the light that has passed through the first object and the second object, and the light is near-infrared light.

[0013] A fifth example of the present invention is an alignment method according to the first or second example, wherein the positional deviation between the first object and the second object is calculated using an optical system, and the optical system includes a stage that adjusts the positions of the first object and the second object horizontally, vertically, and in a rotational direction on a horizontal plane, a light source that is disposed inside the stage and irradiates the light, and a camera that is disposed above the stage and detects the light that has passed through the first object and the second object, and the light is near-infrared light.

[0014] A sixth example of the present invention is the alignment method of the fourth example, wherein the distance between the first object and the second object that can be aligned is 2950 μm or less.

[0015] A seventh example of the present invention is that, in the alignment method of the fourth example, when the distance between the first object and the second object is 1000 μm or more, the numerical aperture of the camera's lens is 0.168 or less.

[0016] An eighth example of the present invention is an alignment method according to the first or second example, wherein the stacked first object and second object are used in the manufacture of any one of an optical semiconductor element, a semiconductor element, or an optical element.

[0017] A ninth example of the present invention is a method for manufacturing a laminate including a first object and a second object, the method comprising: stacking the first object on which a first array having a first periodic structure is formed, and the second object on which a second array having the first periodic structure is formed; irradiating light onto the stacked first object and the second object; detecting a first signal which is a signal of the light that has passed through the first array formed on the first object; detecting a second signal which is a signal of the light that has passed through the second array formed on the second object; calculating a positional shift of the stacked first object and the second object based on the first signal and the second signal; and adjusting the positions of the stacked first object and the second object based on the calculated positional shift, wherein the first array is formed on either the first surface of the first object or the second surface opposite the first surface, and the second array is formed on the surface of the second object that does not face the first object, of the third surface and the fourth surface opposite the third surface.

[0018] A tenth example of the present invention is a manufacturing method according to the ninth example, wherein the first object further has a third array having a second periodic structure different from the first periodic structure, and the second object further has a fourth array having the second periodic structure, and further includes detecting a third signal which is a signal of the light that has passed through the third array formed on the first object, detecting a fourth signal which is a signal of the light that has passed through the fourth array formed on the second object, and calculating the positional shift of the stacked first object and second object based on the first signal, the second signal, the third signal, and the fourth signal, wherein the third array is formed on either the first surface or the second surface of the first object, and the fourth array is formed on the surface of the third surface or the fourth surface of the second object that does not face the first object.

[0019] An eleventh example of the present invention is the manufacturing method of the ninth or tenth example, wherein the laminate is used for manufacturing any one of an optical semiconductor element, a semiconductor element, and an optical element.

[0020] A twelfth example of the present invention is a lithography method for transferring a pattern formed on one of a first object and a second object to the other, the method including: stacking a first object on which a first array having a first periodic structure is formed and a second object on which a second array having the first periodic structure is formed; irradiating the stacked first object and the second object with light; detecting a first signal that is a signal of the light that has passed through the first array formed on the first object; detecting a second signal that is a signal of the light that has passed through the second array formed on the second object; calculating a positional deviation of the stacked first object and the second object based on the first signal and the second signal; a lithography method including adjusting the positions of the stacked first object and the second object based on the misalignment, wherein the first array is formed on either the first surface of the first object or the second surface opposite the first surface, and the second array is formed on the surface of the second object that does not face the first object, either the third surface or the fourth surface opposite the third surface, and when the first array is formed as the pattern on the first object, transferring the first array formed on the first object to the second object, and when the second array is formed as the pattern on the second object, transferring the second array formed on the second object to the first object.

[0021] A thirteenth example of the present invention is the lithography method of the twelfth example, wherein a third array having a second periodic structure different from the first periodic structure is further formed on the first object, and a fourth array having the second periodic structure is further formed on the second object, and further includes detecting a third signal which is a signal of the light that has passed through the third array formed on the first object, detecting a fourth signal which is a signal of the light that has passed through the fourth array formed on the second object, and calculating a positional deviation of the stacked first object and the second object based on the first signal, the second signal, the third signal, and the fourth signal, The method further includes the steps of: when the third array is formed on one of the first surface and the second surface of the first object, and the fourth array is formed on the surface of the third surface and the fourth surface of the second object that does not face the first object, and when the first array and the third array are formed as the pattern on the first object, transferring the first array and the third array formed on the first object to the second object; and when the second array and the fourth array are formed as the pattern on the second object, transferring the second array and the fourth array formed on the second object to the first object.

[0022] A fourteenth example of the present invention is an alignment device comprising: a detection unit that detects signals of light irradiated onto and transmitted through a first object having a first array member with a first periodic structure formed thereon; and a second object having a second array member with the first periodic structure formed thereon; and a calculation unit that calculates a positional misalignment of the stacked first object and the second object based on the signals; wherein the detection unit detects a first signal that is a signal of light that has passed through the first array member formed on the first object, and a second signal that is a signal of light that has passed through the second array member formed on the second object; the calculation unit calculates the positional misalignment based on the first signal and the second signal; the first array member is formed on either the first surface or the second surface opposite the first surface of the first object; and the second array member is formed on the surface of the second object that does not face the first object, of the third surface or the fourth surface opposite the third surface.

[0023] A 15th example of the present invention is an alignment device according to the 14th example, wherein the first object further has a third array having a second periodic structure different from the first periodic structure formed thereon, and the second object further has a fourth array having the second periodic structure formed thereon, the detection unit further detects a third signal which is a signal of the light that has passed through the third array formed on the first object, and a fourth signal which is a signal of the light that has passed through the fourth array formed on the second object, the calculation unit calculates the positional misalignment of the stacked first and second objects based on the first signal, the second signal, the third signal, and the fourth signal, and the third array is formed on either the first surface or the second surface of the first object, and the fourth array is formed on the surface of the third surface or the fourth surface of the second object that does not face the first object.

[0024] A 16th example of the present invention is a program to be executed on a computer, comprising: detecting a signal of light irradiated onto and transmitted through a first object and a second object that are stacked, the first object having a first array having a first periodic structure formed thereon, and a second object having a second array having the first periodic structure formed thereon; calculating a positional misalignment between the stacked first object and the second object based on the signal; detecting a first signal which is a signal of light that has passed through the first array formed on the first object; detecting a second signal which is a signal of light that has passed through the second array formed on the second object; and calculating the positional misalignment based on the first signal and the second signal; wherein the first array is formed on either the first surface of the first object or the second surface opposite the first surface, and the second array is formed on the surface of the second object that does not face the first object, of the third surface and the fourth surface opposite the third surface.

[0025] A 17th example of the present invention is a program in the 16th example, wherein the first object further has a third array having a second periodic structure different from the first periodic structure, and the second object further has a fourth array having the second periodic structure, and further includes detecting a third signal which is a signal of the light that has passed through the third array formed on the first object, detecting a fourth signal which is a signal of the light that has passed through the fourth array formed on the second object, and calculating the positional shift of the stacked first object and second object based on the first signal, the second signal, the third signal, and the fourth signal, wherein the third array is formed on either the first surface or the second surface of the first object, and the fourth array is formed on the surface of the third surface or the fourth surface of the second object that does not face the first object. [Effects of the Invention]

[0026] According to the above example, the alignment accuracy can be further improved. In particular, by applying the function fitting method to the misalignment analysis, high-precision alignment can be achieved even for patterns on the back surface of the substrate. Furthermore, by using a transmitted light path, high signal intensity can be obtained from the pattern on the back surface of the substrate, making it applicable to various semiconductor processes such as exposure, imprinting, and wafer bonding. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a diagram showing an example of the configuration of an alignment device 1 according to the present embodiment. [Figure 2] 2 is a diagram showing an example of the configuration of a first object OB1 and a second object OB2 according to the present embodiment. FIG. [Figure 3] 2 is a diagram showing an example of the configuration of a first object OB1 and a second object OB2 according to the present embodiment. FIG. [Figure 4] 10 is a diagram showing an example of a pattern P2 formed on a second object OB2. FIG. [Figure 5] FIG. 10 is an enlarged view of alignment marks WA and WB. [Figure 6] 10 is a diagram showing an example of a pattern P1 formed on a first object OB1. FIG. [Figure 7] FIG. 1 is an enlarged view of alignment marks XA and XB. [Figure 8] 1 is a diagram illustrating an example of the configuration of a control device 100 according to the present embodiment. [Figure 9] 10 is a flowchart showing an example of a series of processing steps performed by the alignment device 1 according to the present embodiment. [Figure 10] 1 is a diagram illustrating an example of alignment of a second object OB2 with respect to a first object OB1. FIG. [Figure 11] 10 is a diagram illustrating another example of alignment of a second object OB2 with respect to a first object OB1. FIG. [Figure 12] 10 is a diagram showing an example of an image of transmitted light of a first object OB1 and a second object OB2 aligned based on coarse alignment marks MW and MX. FIG. [Figure 13]10A and 10B are diagrams showing a schematic view of the processing from signal detection to calculation of deviation of XY position. [Figure 14] FIG. 10 is a diagram illustrating an example of function fitting. [Figure 15] FIG. 10 is a diagram illustrating an example of deviation in XY position. [Figure 16] FIG. 10 is a diagram showing an example of an image captured using light transmitted through a second object OB2 (wafer). [Figure 17] 1 is a diagram showing an example of an image obtained by capturing light transmitted through a first object OB1 (photomask). FIG. [Figure 18] 10 is a diagram illustrating an example of an image captured by capturing light transmitted through a first object OB1 and a second object OB2 that are stacked. FIG. [Figure 19] 10 is a diagram illustrating an example of precision alignment marks HW1 and HW2 of a second object OB2. FIG. [Figure 20] 20 is a diagram showing an example of a signal W12 detected from light transmitted through the precision alignment mark HW1 in FIG. 19. FIG. [Figure 21] 20 is a diagram showing an example of a signal W22 detected from light transmitted through the precision alignment mark HW2 in FIG. 19. FIG. [Figure 22] 10A and 10B are diagrams illustrating examples of experimental results in examples and comparative examples. [Figure 23] FIG. 2 is a diagram illustrating an example of the configuration of a first object OB1 in the embodiment. [Figure 24] FIG. 2 is a diagram illustrating an example of the configuration of a second object OB2 in the embodiment. [Figure 25] FIG. 1 is a diagram for explaining an experimental method of an example. [Figure 26] FIG. 1 is a diagram for explaining an experimental method of an example. [Figure 27] FIG. 1 is a diagram for explaining an experimental method of an example. [Figure 28] FIG. 1 is a diagram for explaining an experimental method of an example. [Figure 29] FIG. 1 is a diagram for explaining an experimental method of an example. [Figure 30] 10 is a diagram showing the relationship between the object-side NA of the lens 22 and the focusable distance. [Figure 31]FIG. 1 is a diagram showing the experimental results of Example 1. [Figure 32] FIG. 1 is a diagram showing the experimental results of Example 1. [Figure 33] FIG. 1 is a diagram showing the experimental results of Example 1. [Figure 34] FIG. 10 is a diagram showing the experimental results of Example 2. [Figure 35] FIG. 10 is a diagram showing the experimental results of Example 2. [Figure 36] FIG. 10 is a diagram showing the experimental results of Example 2. [Figure 37] FIG. 10 is a diagram showing the experimental results of Comparative Example 1. [Figure 38] FIG. 10 is a diagram showing the experimental results of Comparative Example 1. [Figure 39] FIG. 10 is a diagram showing the experimental results of Comparative Example 1. [Figure 40] FIG. 10 is a diagram showing the experimental results of Example 3. [Figure 41] FIG. 10 is a diagram showing the experimental results of Example 3. [Figure 42] FIG. 10 is a diagram showing the experimental results of Example 3. [Figure 43] FIG. 10 is a diagram showing the experimental results of Example 4. [Figure 44] FIG. 10 is a diagram showing the experimental results of Example 4. [Figure 45] FIG. 10 is a diagram showing the experimental results of Example 4. [Figure 46] FIG. 10 is a diagram showing the experimental results of Example 5. [Figure 47] FIG. 10 is a diagram showing the experimental results of Example 5. [Figure 48] FIG. 10 is a diagram showing the experimental results of Example 5. [Figure 49] FIG. 10 is a diagram showing the experimental results of Comparative Example 2. [Figure 50] FIG. 10 is a diagram showing the experimental results of Comparative Example 2. [Figure 51] FIG. 10 is a diagram showing the experimental results of Comparative Example 2. [Figure 52] FIG. 10 is a diagram showing the experimental results of Example 6. [Figure 53] FIG. 10 is a diagram showing the experimental results of Example 6. [Figure 54]FIG. 10 is a diagram showing the experimental results of Example 6. [Figure 55] FIG. 10 is a diagram showing the experimental results of Example 7. [Figure 56] FIG. 10 is a diagram showing the experimental results of Example 7. [Figure 57] FIG. 10 is a diagram showing the experimental results of Example 7. [Figure 58] FIG. 10 is a diagram showing the experimental results of Comparative Example 3. [Figure 59] FIG. 10 is a diagram showing the experimental results of Comparative Example 3. [Figure 60] FIG. 10 is a diagram showing the experimental results of Comparative Example 3. [Figure 61] FIG. 10 is a diagram showing the experimental results of Example 8. [Figure 62] FIG. 10 is a diagram showing the experimental results of Example 8. [Figure 63] FIG. 10 is a diagram showing the experimental results of Example 8. [Figure 64] FIG. 10 is a diagram showing the experimental results of Example 9. [Figure 65] FIG. 10 is a diagram showing the experimental results of Example 9. [Figure 66] FIG. 10 is a diagram showing the experimental results of Example 9. [Figure 67] FIG. 10 is a diagram showing the experimental results of Comparative Example 4. [Figure 68] FIG. 10 is a diagram showing the experimental results of Comparative Example 4. [Figure 69] FIG. 10 is a diagram showing the experimental results of Comparative Example 4. [Figure 70] FIG. 10 is a diagram showing the experimental results of Comparative Example 5. [Figure 71] FIG. 10 is a diagram showing the experimental results of Comparative Example 5. [Figure 72] FIG. 10 is a diagram showing the experimental results of Comparative Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, with reference to the drawings, embodiments of an alignment method, a manufacturing method, a lithography method, an alignment apparatus, and a program according to the present invention will be described.

[0029] [Configuration example of alignment device (laminate manufacturing device)] Fig. 1 is a diagram showing an example of the configuration of an alignment device 1 according to this embodiment. The alignment device 1 is also a laminate manufacturing device 1. As shown in Fig. 1, the alignment device 1 includes a camera 20, a fixed stage 30, an XYZθ-axis movable stage 40, an illumination device (light source) 50, and a control device 100. The camera 20, the fixed stage 30, the XYZθ-axis movable stage 40, and the illumination device 50 are an example of an "optical system."

[0030] In the diagram, X represents one direction (axis) that forms a horizontal plane, Y represents another direction (axis) that forms the horizontal plane, and Z represents the vertical direction (vertical axis) that is perpendicular to the horizontal plane. In other words, X represents the width direction, Y represents the depth direction, and Z represents the height direction.

[0031] The alignment device 1 stacks a first object OB1 and a second object OB2, irradiates light from below or above the first object OB1 and the second object OB2, detects the transmitted light that passes through the first object OB1 and the second object OB2 as an electrical signal, calculates the positional deviation between the first object OB1 and the second object OB2 based on the transmitted light signal, and adjusts the position of one or both of the first object OB1 and the second object OB2 based on the positional deviation.

[0032] The first object OB1 is, for example, a photomask, a mold, or a second substrate (second wafer). The second object OB2 is a substrate (wafer) and may be, for example, various types of glass, silicon, or a compound semiconductor. A stack of the first object OB1 and the second object OB2 may be used to manufacture any of an optical semiconductor element, a semiconductor element, and an optical element.

[0033] The alignment device 1 typically adjusts the position of the second object OB2, which is a substrate, relative to the first object OB1, such as a photomask or a mold, when stacking the first object OB1 and the second object OB2. In other words, of the first object OB1 and the second object OB2, one of the second objects OB2, the second object OB2, is the object to be aligned. Patterns are formed on the first object OB1 and the second object OB2 to perform alignment during stacking. Details of each pattern will be described later.

[0034] The camera 20 is disposed, for example, above the fixed stage 30, the XYZθ-axis movable stage 40, and the lighting device 50. The camera 20 detects transmitted light, which is light that is irradiated from the lighting device 50 and transmitted through the first object OB1 and the second object OB2, via the lens 22. The bit depth of the camera 20 may be 8 bits or more, and preferably 12 bits or more. The NA (numerical aperture) of the lens 22, i.e., the observation magnification of the camera 20, may be a low magnification such as 0.5x, 1.0x, or 2.0x.

[0035] As will be explained in the examples below, it is necessary to accurately detect an amplitude ratio of 0.1. Therefore, it is preferable that the camera 20 has 32 or more gradations, i.e., 5 or more bits. In terms of the cost of the camera 20 and the processing power of the system, it is more preferable that the camera 20 has a resolution of about 12 or 16 bits.

[0036] The fixed stage 30 holds a first object OB1 under the control of the control device 100, for example, and stacks the first object OB1 on a second object OB2 placed on the XYZθ-axis movable stage 40.

[0037] A second object OB2 is placed on the XYZθ-axis movable stage 40. The XYZθ-axis movable stage 40, for example, moves the placed second object OB2 in accordance with the control of the control device 100. It moves in the horizontal direction (XY direction), vertical direction (Z direction), and rotation direction on the horizontal plane (θ direction).

[0038] The illumination device 50 is disposed, for example, below the camera 20, the fixed stage 30, and the XYZθ-axis movable stage 40. Alternatively, the illumination device 50 may be disposed inside the XYZθ-axis movable stage 40. The illumination device 50 irradiates the stacked first object OB1 and second object OB2 with light from below the XYZθ-axis movable stage 40. For example, the illumination device 50 may be a light source capable of uniformly irradiating the imaging area of ​​the camera 20. Specifically, the illumination device 50 may irradiate near-infrared light with a wavelength of approximately 1050 nm. Note that when the camera 20 is disposed below the fixed stage 30, the XYZθ-axis movable stage 40, and the illumination device 50, the illumination device 50 may be disposed above them. In this case, the illumination device 50 irradiates the stacked first object OB1 and second object OB2 with light from above.

[0039] The control device 100 controls, for example, the camera 20, the fixed stage 30, the XYZθ-axis movable stage 40, and the lighting device 50 to stack and align the first object OB1 and the second object OB2.

[0040] In addition to the above-mentioned camera 20, fixed stage 30, XYZθ axis movable stage 40, lighting device 50, and control device 100, the alignment device 1 may further include a coating device 60, an ultraviolet irradiation device 70, etc.

[0041] The applicator 60, under the control of the controller 100, applies, for example, an ultraviolet curable resin containing a fluorescent dye (an ultraviolet curable visible fluorescent liquid) between the first object OB1 and the second object OB2.

[0042] The ultraviolet irradiation device 70 may, for example, cure the ultraviolet curable resin by irradiating ultraviolet rays onto the first object OB1 and the second object OB2 to which the ultraviolet curable resin has been applied, in accordance with the control of the control device 100. In this way, the stacked first object OB1 and the second object OB2 are bonded together by the ultraviolet curable resin, and a stacked body including the first object OB1 and the second object OB2 is produced.

[0043] [Configuration of the first object and the second object (laminated body)] Next, the configuration of the first object OB1 and the second object OB2 will be described. Figures 2 and 3 are diagrams showing an example of the configuration of the first object OB1 and the second object OB2 according to this embodiment.

[0044] In this embodiment, a pattern P1 is formed on the first object OB1, and a pattern P2 is formed on the second object OB2.

[0045] For example, as shown in Fig. 2, the pattern P1 is formed on the back surface of the first object OB1, which is the surface facing the second object OB2. For example, the pattern P1 may be formed by removing a portion of a chromium film or the like formed on the back surface by etching or the like. The front surface of the first object OB1 is an example of the "first surface," and the back surface of the first object OB1 is an example of the "second surface."

[0046] On the other hand, pattern P2 is formed on the rear surface of second object OB2, which is the surface that does not face first object OB1, out of the front and rear surfaces. Pattern P2 may be formed, for example, by removing a portion of a metal light-shielding film formed on the rear surface by etching or the like. The front surface of second object OB2 is an example of a "third surface," and the rear surface of second object OB2 is an example of a "fourth surface."

[0047] 3, the pattern P1 may be formed on the front surface of the first object OB1, which is the surface that does not face the second object OB2, out of the front and back surfaces. Even when the pattern P1 is formed on the front surface of the first object OB1, the pattern P2 is formed on the back surface of the second object OB2.

[0048] The following describes the pattern P2 formed on the second object OB2 before the pattern P1 formed on the first object OB1. Fig. 4 is a diagram showing an example of the pattern P2 formed on the second object OB2.

[0049] The pattern P2 includes alignment marks WA and WB. The alignment marks WA and WB are formed on the outer side (near the outer edge) of the front or back surface of the second object OB2. By forming the alignment marks WA and WB on the outer side, misalignment in the rotational direction (θ direction) can be adjusted with greater precision. For example, a circuit pattern may be formed between the alignment marks WA and WB.

[0050] 5 is an enlarged view of the alignment marks WA and WB. The alignment marks WA and WB include a rough alignment mark MW and a fine alignment mark HW1.

[0051] The rough alignment mark MW is a mark for roughly aligning the positions of the first object OB1 and the second object OB2. The rough alignment mark MW may be, for example, a cross-shaped mark, and two rough alignment marks MW are formed at positions spaced apart from each other on a diagonal line.

[0052] The precision alignment mark HW1 is a mark for precisely aligning the positions of the first object OB1 and the second object OB2.

[0053] The precision alignment mark HW1 may have a periodic structure in which a large number of bars are arranged at intervals of a period p1. The period p1 may be, for example, about 45.0 μm. The precision alignment mark HW1 is an example of a "first array."

[0054] The period p1 of the precision alignment marks HW1 may be five times or more the pixel size of the camera 20, and more preferably nine times or more.

[0055] Next, the pattern P1 formed on the first object OB1 will be described. Fig. 6 is a diagram showing an example of the pattern P1 formed on the first object OB1.

[0056] The pattern P1 includes alignment marks XA and XB. The alignment marks XA and XB are formed on the outer side (near the outer edge) of the front or back surface of the first object OB1. By forming the alignment marks XA and XB on the outer side, misalignment in the rotational direction (θ direction) can be adjusted with greater precision. For example, a circuit pattern may be formed between the alignment marks XA and XB.

[0057] 7 is an enlarged view of the alignment marks XA and XB. The alignment marks XA and XB include a rough alignment mark MX and a fine alignment mark HX1.

[0058] The coarse alignment mark MX is a mark for roughly aligning the positions of the first object OB1 and the second object OB2, similar to the above-mentioned coarse alignment mark MW.

[0059] The coarse alignment marks MX may be, for example, square marks, and similar to the coarse alignment marks MW, two of them are formed at positions spaced apart from each other on a diagonal line.

[0060] The precision alignment mark HX1 is a mark for precisely aligning the positions of the first object OB1 and the second object OB2, similar to the precision alignment mark HW1 described above.

[0061] Like the precision alignment mark HW1, the precision alignment mark HX1 may have a periodic structure in which a large number of bars are arranged at intervals of a period p1. The precision alignment mark HX1 is an example of a "second array."

[0062] The period p1 of the precision alignment marks HX1 may be five times or more the pixel size of the camera 20, and more preferably nine times or more.

[0063] When the first object OB1 and the second object OB2 are stacked, the precision alignment mark HX1 formed as a pattern P1 on the first object OB1 and the precision alignment mark HW1 formed as a pattern P2 on the second object OB2 are formed so as not to overlap each other when viewed from above or below (i.e., in the Z direction).

[0064] The patterns P1 and P2 may be formed using, for example, photolithography or electron beam lithography, which transfers a pattern formed on one side to the other side.

[0065] Specifically, if precision alignment mark HX1 is first formed on first object OB1 as part of pattern P1, then precision alignment mark HX1 may be transferred to second object OB2 as precision alignment mark HW1. Also, if precision alignment mark HW1 is first formed on second object OB2 as part of pattern P2, then precision alignment mark HW1 may be transferred to first object OB1 as precision alignment mark HX1.

[0066] [Control device configuration] Next, a description will be given of the configuration of the control device 100. Fig. 8 is a diagram showing an example of the configuration of the control device 100 according to this embodiment. The control device 100 includes, for example, a communication interface 110, an input interface 120, an output interface 130, a storage unit 140, and a processing unit 150.

[0067] The communication interface 110 includes, for example, a network interface card (NIC) or a wireless communication module including a receiver and a transmitter. The communication interface 110 communicates with external devices via a network such as a local area network (LAN) or a wide area network (WAN). Examples of the external devices include the camera 20, fixed stage 30, XYZθ-axis movable stage 40, lighting device 50, coating device 60, and ultraviolet irradiation device 70.

[0068] The input interface 120 accepts various input operations from a user, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing unit 150. For example, the input interface 120 includes a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touch panel, etc. The input interface 120 may be, for example, a voice user interface that accepts voice input including a microphone, etc.

[0069] The output interface 130 includes, for example, a display and a speaker. The display displays images generated by the processing unit 150, a GUI (Graphical User Interface) for receiving various input operations from the user, and the like. For example, the display is an LCD (Liquid Crystal Display), an organic EL (Electro Luminescence) display, or the like. The speaker outputs information input from the processing unit 150 as sound.

[0070] The storage unit 140 is realized by, for example, a hard disk drive (HDD), a flash memory, an electrically erasable programmable read only memory (EEPROM), a read only memory (ROM), a random access memory (RAM), etc. The storage unit 140 stores various programs such as firmware and application programs.

[0071] The processing unit 150 includes, for example, an acquisition unit 151, an image processing unit 152, a calculation unit 153, and an output control unit 154. The image processing unit 152 is an example of a "detection unit."

[0072] The components of the processing unit 150 are realized by a processor such as a central processing unit (CPU) or a graphics processing unit (GPU) executing a program stored in the storage unit 140. Some or all of the components of the processing unit 150 may be realized by hardware such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a system on chip (SOC), or may be realized by a combination of software and hardware.

[0073] [Processing flow of the alignment device] The following describes the flow of a series of processes performed by the alignment device 1 with reference to a flowchart. Fig. 9 is a flowchart showing an example of the flow of a series of processes performed by the alignment device 1 according to this embodiment. The processes of this flowchart may be repeated at predetermined intervals, for example.

[0074] First, the output control unit 154 of the control device 100 controls the camera 20, the fixed stage 30 that holds the first object OB1 on which the pattern P1 is formed, the XYZθ-axis movable stage 40 on which the second object OB2 on which the pattern P2 is formed is placed, and the lighting device 50 to align the first object OB1 and the second object OB2 (step S100). Note that the process (alignment) of S100 may be performed by a user such as a manufacturer or an operator instead of by the control device 100.

[0075] Specifically, the output control unit 154 irradiates light from the illumination device 50 toward the stacked first object OB1 and second object OB2. The light irradiated from the illumination device 50 passes through the second object OB2 placed on the XYZθ-axis movable stage 40, and further passes through the first object OB1 held by the fixed stage 30, and is received by the camera 20 via the lens 22. In other words, the camera 20 captures an image of the transmitted light.

[0076] The acquisition unit 151 of the control device 100 acquires an image of the transmitted light from the camera 20.

[0077] Next, the image processing unit 152 detects the two rough alignment marks MX and the two rough alignment marks MW from the image of the transmitted light (step S102).

[0078] For example, the image processing unit 152 may detect two rough alignment marks MX from only one of the alignment marks XA and XB formed as pattern P1 on the first object OB1, or may detect two rough alignment marks MX from both XA and XB.

[0079] Similarly, for example, the image processing unit 152 may detect two rough alignment marks MW from only one of the alignment marks WA and WB formed as pattern P2 on the second object OB2, or may detect two rough alignment marks MW from both WA and WB.

[0080] Next, the image processing unit 152 detects the center of gravity GX based on the two rough alignment marks MX, and detects the center of gravity GW based on the two rough alignment marks MW (step S104).

[0081] Next, the calculation unit 153 calculates the XYθ movement amount of the second object OB2 relative to the first object OB1 based on the two rough alignment marks MX, the two rough alignment marks MW, the center of gravity GX, and the center of gravity GW (step S106). The XYθ movement amount represents the movement amount (distance) on the XY plane (horizontal plane) and the movement amount in the θ direction (rotational direction) on the XY plane (i.e., rotation angle).

[0082] Next, the output control unit 154 adjusts the relative position of the second object OB2 in the XY plane with respect to the first object OB1 by controlling the XYZθ-axis movable stage 40 based on the XYθ movement amount (step S108). That is, the second object OB2 is roughly aligned with respect to the first object OB1 based on the two rough alignment marks MX and the two rough alignment marks MW. The processing of S108 may be performed by the user instead of by the control device 100.

[0083] 10 is a diagram showing an example of alignment of a second object OB2 with respect to a first object OB1. As shown in the figure, for example, of alignment marks WA and WB patterned on the second object OB2, two rough alignment marks MW are detected only from the WA on the left side of the figure. In this case, the center of gravity GW is detected based on the two rough alignment marks MW detected from the alignment mark WA.

[0084] Furthermore, the center of gravity GX is detected based on two rough alignment marks MX detected from alignment marks XA, XB patterned on the first object OB1, the position of which corresponds to alignment mark WA.

[0085] Then, the XYθ movement amount is calculated based on the two rough alignment marks MW and the center of gravity GW derived from the alignment mark WA on the left side of the drawing, and the two rough alignment marks MX and the center of gravity GX derived from the alignment mark WX on the left side of the drawing. In this way, alignment may be performed using only one of the alignment marks.

[0086] 11 is a diagram showing another example of alignment of a second object OB2 with respect to a first object OB1. In the above-mentioned FIG. 10, the alignment is performed using only one of the alignment marks, but this is not limiting. For example, as shown in FIG. 10, the alignment may be performed using both alignment marks.

[0087] Returning to the description of the flowchart, next, image processing unit 152 detects precision alignment marks HX1 and HW1 from the image of transmitted light through first object OB1 and second object OB2 aligned based on coarse alignment marks MW and MX (step S110).

[0088] 12 is a diagram showing an example of an image of transmitted light of the first object OB1 and the second object OB2 aligned based on the coarse alignment marks MW and MX. As described above, the fine alignment marks HX1 and HW1 are patterned in advance so as not to overlap with each other, and therefore are detected without overlapping with each other in the image of transmitted light.

[0089] Returning to the description of the flowchart, next, image processing unit 152 detects a signal indicating the transmitted light through precision alignment mark HX1 of period p1 (hereinafter, signal W11) and a signal indicating the transmitted light through precision alignment mark HW1 of period p1 (hereinafter, signal W12) (step S112).

[0090] The signal W11 is an example of a "first signal," and the signal W12 is an example of a "second signal."

[0091] Each signal may be generated, for example, by plotting the signal intensity (received light intensity) of each pixel in the X direction. That is, each signal may be a discrete signal that indicates the signal intensity in the X direction.

[0092] Next, the calculation unit 153 fits each of the signals W11 and W12 to a predetermined function (step S114).

[0093] Next, the calculation unit 153 calculates the deviation of the XY positions between the first object OB1 and the second object OB2 based on the signals W11 and W12 fitted to the function (step S116). The deviation of the XY positions is the deviation (distance) between the positions of the objects on the XY plane.

[0094] Next, the output control unit 154 adjusts the relative position of the second object OB2 with respect to the first object OB1 in the XY plane by controlling the XYZθ-axis movable stage 40 based on the deviation of the XY positions (step S118). That is, the second object OB2 is precisely aligned with respect to the first object OB1 based on the precision alignment marks HX1 and HW1. The processing of S118 may be performed by the user instead of by the control device 100. This completes the series of processing steps in the flowchart.

[0095] If precision alignment marks HX1 and HW1 are formed on the first object OB1 and the second object OB2, respectively, it is possible to perform the alignment in step S118, but if the processing of S118 is performed by the control device 100, the presence of precision alignment marks HW2 and HX2 may make it easier to recognize the direction of displacement. For this reason, precision alignment marks HW2 and HX2 may be formed on the first object OB1 and the second object OB2, respectively.

[0096] The precision alignment mark HW2 may have a periodic structure in which a large number of bars are arranged at intervals of a period p2. The period p2 may be any period different from the period p1, and may be, for example, about 46.0 μm. The precision alignment mark HW2 is an example of a "third array."

[0097] Like the precision alignment mark HW2, the precision alignment mark HX2 may have a periodic structure in which a large number of bars are arranged at intervals of a period p2. The precision alignment mark HX2 is an example of a "fourth array."

[0098] 13 is a diagram showing a schematic diagram of the process from signal detection to calculation of XY position deviation. A signal W11 is detected from light transmitted through precision alignment mark HX1 with period p1, and a signal W12 is detected from light transmitted through precision alignment mark HW1 with period p1. Each of signals W11 and W12 is fitted to a function. Then, the XY position deviation is calculated from signals W11 and W12 fitted to the function.

[0099] 14 is a diagram illustrating an example of function fitting. As illustrated, each of the signals W11 and W12, which are discrete signals of signal strength, may be fitted to, for example, a sine function or a cosine function.

[0100] 15 is a diagram showing an example of the deviation in XY position. For example, the calculation unit 153 calculates the deviation between the signals W11 and W12 in each period (e.g., the distance between the peaks). In this case, the calculation unit 153 may calculate the deviation for each period and use the average value of the deviations for all periods as the deviation between the signals W11 and W12. The calculation unit 153 then calculates the deviation between the signals W11 and W12 as the deviation in the XY position between the first object OB1 and the second object OB2.

[0101] The calculation unit 153 may calculate the deviation between the signals W21 and W22 instead of calculating the deviation between the signals W11 and W12, and use this as the deviation in the XY positions between the first object OB1 and the second object OB2.

[0102] The signal W21 is a signal representing the transmitted light through the precision alignment mark HX2 having the period p2, and the signal W22 is a signal representing the transmitted light through the precision alignment mark HW2 having the period p2.

[0103] Although the precision alignment marks HX1, HX2, HW1, and HW2 have been described as having a structure in which a number of bars are arranged in the X direction at intervals of period p1 or p2, this is not limiting. For example, the precision alignment marks HX1, HX2, HW1, and HW2 may have a structure in which a number of bars are arranged in the Y direction at intervals of period p1 or p2. In this case, not only the deviation in the X position between the first object OB1 and the second object OB2 but also the deviation in the Y position can be calculated. As a result, the first object OB1 and the second object OB2 can be precisely aligned on the XY plane.

[0104] According to the embodiment described above, the alignment apparatus 1 stacks a first object OB1 (for example, a photomask) and a second object OB2 (for example, a wafer).

[0105] At least precision alignment marks HX1 (an example of a "first array") are formed as pattern P1 on the first object OB1. In addition, precision alignment marks HX2 (an example of a "third array") may be formed as pattern P1 on the first object OB1.

[0106] At least precision alignment marks HW1 (an example of a "second array") are formed as pattern P2 on the second object OB2. In addition, precision alignment marks HW2 (an example of a "fourth array") may be formed as pattern P1 on the second object OB2.

[0107] The pattern P1 is formed on either the front or back surface of the first object OB1, and the pattern P2 is formed on the back surface of the second object OB2, which is the surface that does not face the first object OB1.

[0108] The alignment device 1 irradiates near-infrared light onto the stacked first object OB1 and second object OB2.

[0109] When a precision alignment mark HX1 is formed as a pattern P1 on a first object OB1 and a precision alignment mark HW1 is formed as a pattern P2 on a second object OB2, the alignment device 1 detects a signal W11 (an example of a "first signal") indicating the transmitted light through the precision alignment mark HX1 with a period p1 and a signal W12 (an example of a "second signal") indicating the transmitted light through the precision alignment mark HW1 with a period p1.

[0110] When a precision alignment mark HX2 is formed as a pattern P1 on a first object OB1 and a precision alignment mark HW2 is formed as a pattern P2 on a second object OB2, the alignment device 1 detects a signal W21 (an example of a "third signal") indicating the transmitted light through the precision alignment mark HX2 with a period p2 and a signal W22 (an example of a "fourth signal") indicating the transmitted light through the precision alignment mark HW2 with a period p2.

[0111] The alignment device 1 calculates the deviation in the XY positions of the first object OB1 and the second object OB2. Based on the deviation in the XY positions, the alignment device 1 adjusts the relative position of the second object OB2 with respect to the first object OB1 in the XY plane.

[0112] This type of processing can further improve alignment accuracy. In particular, applying a function fitting method to misalignment analysis enables highly accurate alignment of the pattern P1 on the backside of the first object OB1. Furthermore, detecting the light transmitted through the stacked first object OB1 and second object OB2 makes it possible to obtain a high signal strength from the pattern P2 on the backside of the second object OB2, which can be applied to various semiconductor processes such as exposure, imprinting, and wafer bonding.

[0113] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Example]

[0114] Examples are described below. The camera 20 used was an ABA-013VIR (Aval Data). The lens 22 used was an MP-1M-65-NIR (Optoart). The lighting device 50 used was a TH2-100X100IR105 (CSS). The near-infrared light used had a wavelength of 1050 nm. A glass mask was used for the first object OB1, and a pattern P1 was formed by etching a 100 nm chromium film. The second object OB2 used a 280 μm silicon wafer with polished surfaces. A metal light-shielding film was formed as pattern P2 on the back surface of the second object OB2.

[0115] Fig. 16 is a diagram showing an example of an image obtained by capturing transmitted light through a second object OB2 (wafer). Fig. 17 is a diagram showing an example of an image obtained by capturing transmitted light through a first object OB1 (photomask). In order to calculate deviations in not only the X position but also the Y position, precision alignment marks HX1, HX2, HW1, and HW2 are patterned in the illustrated image not only in the X direction but also in the Y direction.

[0116] 18 is a diagram showing an example of an image obtained by capturing light transmitted through the stacked first object OB1 and second object OB2. As shown in the figure, all precision alignment marks are detected without overlapping.

[0117] FIG. 19 is a diagram showing an example of precision alignment marks HW1 and HW2 of the second object OB2. The period p1 of the precision alignment mark HW1 in FIG. 19 is 58.56 [μm]. FIG. 20 is a diagram showing an example of a signal W12 detected from light transmitted through the precision alignment mark HW1 in FIG. 19. FIG. 21 is a diagram showing an example of a signal W22 detected from light transmitted through the precision alignment mark HW2 in FIG. 19. The amplitude of the signal W12 was 42.266, the phase shift was −3.426 [px], and the period was 11.712 [px]. The amplitude of the signal W22 was 45.339, the phase shift was 1.339 [px], and the period was 12.108 [px].

[0118] 22 is a diagram showing an example of experimental results in Examples and Comparative Examples. Examples 1-9 are methods employing a transmission optical system that succeeded in focusing various precision alignment marks. On the other hand, Comparative Examples 1-4 are methods employing a transmission optical system that failed to focus various precision alignment marks. Comparative Example 5 is a method employing a reflection optical system that failed to focus various precision alignment marks.

[0119] Details of Examples 1-9 and Comparative Examples 1-5 will be described later, but in order to focus on both the first object OB1 and the second object OB2, the NA (numerical aperture) on the object side of the lens 22 needs to be 0.168 or less.

[0120] The NA can be calculated from the following formula: M represents the magnification, and can be calculated by dividing the size of the mark on the image by the size of the actual mark. F represents the F-number of the lens 22.

[0121] NA=M / {2(1+M)F}

[0122] A common condition for the configurations of Examples 1-9 and Comparative Examples 1-5 is that a sensor such as Si-CMOS, InGaAs, or PbS may be used for the camera 20. In particular, since a high signal strength for near-infrared light is preferable, InGaAs or PbS is preferable. In Examples 1-9 and Comparative Examples 1-5, an ABA-013VIR (Aval Data) was used as the camera 20.

[0123] The illumination device 50 may be a surface light source, a spot light source, a fiber light source, a VCSEL (Vertical Cavity Surface Emitting Laser), or the like. Since uniform illuminance within a plane is particularly desirable, it is preferable to employ a surface light source or a VCSEL for the illumination device 50. The wider the range over which the illuminance is uniform within a plane, the wider the pattern analysis range can be, and the greater the number of mark periods can be. As a result, the detection accuracy of the amount of phase shift can be improved.

[0124] The light emitted from the lighting device 50 may be configured to be incident on the camera 20 from the front. This allows the distance between the lighting device 50 and the camera 20 to be shortened, and the amount of light received by the camera 20 to be increased. As a result, the signal strength can be increased and the amplitude of the fitting function can be increased, thereby improving the accuracy of detecting the period and further improving the accuracy of detecting the amount of positional displacement. In Examples 1-9 and Comparative Examples 1-5, near-infrared light with a wavelength of 1050 [nm] was used as the light emitted from the lighting device 50.

[0125] 23 is a diagram showing an example of the configuration of the first object OB1 in the examples. In Examples 1-9 and Comparative Examples 1-5, a colorless photomask was used as the first object OB1. It was made of glass, and had an outer diameter of 127 mm × 127 mm and a thickness of 2.3 mm. A 100 nm thick chromium film was formed on the rear surface of the glass, and a reflective (light-blocking) pattern P1 was formed by etching a portion of the chromium film.

[0126] FIG. 24 is a diagram showing an example of the configuration of the second object OB2 in the examples. In Examples 1-9 and Comparative Examples 1-5, a double-side polished wafer was used as the second object OB2. The material was silicon, and the outer diameter was a circle with a diameter of 51.2 mm and a thickness of 280 μm. A gold (Au) film was formed on the backside of the wafer, and a titanium (Ti) film was formed between the wafer and the gold film to increase adhesion between them. The titanium film was 10 nm thick, and the gold film was 200 nm thick. A reflective (light-blocking) pattern P2 was formed by etching portions of the titanium film and gold film.

[0127] 25 to 29 are diagrams for explaining the experimental method of the example. As shown in Fig. 25, experiments were conducted while changing the size of the gap (distance) formed between the first object OB1 and the second object OB2. Note that reference numeral 24 denotes a close-up ring (also called a close-up tube or extension tube) connected to the end of the lens 22 on the camera 20 side. The close-up ring 24 is used to adjust the magnification of the camera 20, and experiments were conducted while changing the length of this close-up ring 24.

[0128] The lens 22 may be, for example, M5018-VSW (manufactured by Computer) or OS-TCM1.0-H1.1-CEI (manufactured by Sigma Koki).

[0129] 26, first, when the gap between the first object OB1 and the second object OB2 is 0 μm, the control device 100 irradiates light toward the stacked first object OB1 and the second object OB2 and captures images of the first object OB1 and the second object OB2. Hereinafter, the state in which the gap is 0 μm will be referred to as the initial state. In the initial state, the control device 100 focuses the camera 20 on the precision alignment mark HX2 formed as the pattern P1 on the first object OB1 and the precision alignment mark HW2 formed as the pattern P2 on the second object OB2.

[0130] Next, the control device 100 changes the gap from the initial state while irradiating light toward the stacked first object OB1 and second object OB2, and captures images of the first object OB1 and the second object OB2, thereby acquiring new images of the first object OB1 and the second object OB2.

[0131] Next, the control device 100 calculates an analysis range R on the newly acquired image. HX2 A signal W21 indicating the transmitted light of the precision alignment mark HX2 having the period p2 is detected from a part of the precision alignment mark HX2 included in the analysis range R HW2 A signal W22 indicating transmitted light through the precision alignment mark HW2 of the period p2 is detected from a part of the precision alignment mark HW2 included in the period p2.

[0132] Figure 27 shows the analysis range R HX2 and analysis range R HW2 1 is a diagram showing an example of the precision alignment marks HX2 and HW2. As shown in the figure, the precision alignment marks HX2 and HW2 are configured such that white areas (light transmitting areas) and black areas (light reflecting areas) are alternately repeated periodically. A combination of one white area and one black area is one period (T=1). In the embodiment, the analysis range R HX2 and analysis range R HW2 is set to include 14 periods (T=14).

[0133] Next, the control device 100 fits each of the signals W21 and W22 to a predetermined function to calculate the amplitude, phase, and period.

[0134] 28 shows an example of the analysis results of the signal W22 detected from the light transmitted through the precision alignment mark HW2. The vertical axis represents signal intensity, and the horizontal axis represents pixels [px]. In the example shown, the amplitude of the signal W22 is 33.254, the phase is 3.135 [px], and the period is 12.465 [px].

[0135] 29 is a diagram showing an example of the analysis results of the signal W21 detected from the light transmitted through the precision alignment mark HX2. In the example shown, the amplitude of the signal W21 is 30.337, the phase is 3.628 [px], and the period is 12.462 [px].

[0136] The control device 100 further calculates the amplitude ratio. For example, in the examples of Fig. 28 and Fig. 29, the amplitude ratio = 33.254 ÷ 30.337 = 1.10 (rounded to two decimal places). The amplitude ratio is not involved in determining whether or not focusing has been achieved, but the amplitude ratio tends to decrease as the gap increases.

[0137] The control device 100 further calculates the period difference. For example, in the examples of Figures 28 and 29, period difference = 12.465 [px] - 12.462 [px] = 0.003 [px]. In this embodiment, if the period difference is 0.05 [px] or more, it is considered that focusing has failed, and if the period difference is less than 0.05 [px], it is considered that focusing has succeeded.

[0138] The control device 100 may further calculate the amount of misalignment in the X direction or the Y direction. For example, in the examples of FIGS. 28 and 29, the absolute value of the amount of phase shift is |3.135 [px] - 3.628 [px]| = 0.493 [px]. The control device 100 calculates the amount of misalignment by multiplying the absolute value of the amount of phase shift by the pixel size. For example, if the pixel size is 5.0 [μm / px], the amount of misalignment is calculated as 5.0 [μm / px] × 0.493 [px] = 2.465 [μm].

[0139] The larger the gap, the smaller the amplitude of the signal W22 detected from the light transmitted through the precision alignment mark HW2 on the second object OB2, which is a wafer. As a result, a shift occurs in the period of the fitting function, and the detection accuracy of the phase change amount decreases. Therefore, an appropriate NA (object-side NA) of the lens 22 is required depending on the size of the gap.

[0140] Fig. 30 is a diagram showing the relationship between the object-side NA of the lens 22 and the focusable distance. The vertical axis of the graph in Fig. 30 represents the maximum gap amount [µm], and the horizontal axis represents the object-side NA.

[0141] The larger the gap between the first object OB1 and the second object OB2, the more versatile the applications. For example, the larger the gap, the thicker each object can be, or the number of objects can be increased. Therefore, the graph in Figure 30 plots the results of Examples 1-9, which are successful focusing examples shown in Figure 22, with relatively large gaps.

[0142] Specifically, among Examples 1-2, which all share the same object-side NA of 0.094, the results for Example 2 (NA = 0.094, gap = 2800 μm) are plotted, as they have the larger gap. Similarly, among Examples 3-5, which all share the same object-side NA of 0.140, the results for Example 5 (NA = 0.140, gap = 2950 μm) are plotted, as they have the largest gap. Among Examples 6-7, which all share the same object-side NA of 0.168, the results for Example 7 (NA = 0.168, gap = 1750 μm) are plotted, and among Examples 8-9, which all share the same object-side NA of 0.650, the results for Example 9 (NA = 0.650, gap = 700 μm) are plotted, as they have the largest gap.

[0143] For example, when considering practical uses of the stacked first object OB1 and second object OB2, it is preferable that the gap be at least 1000 μm or more. To meet this requirement, as described above, it is understood that the NA of lens 22 should be at least 0.168 or less.

[0144] Furthermore, the gap between the first object OB1 and the second object OB2 that can be aligned may be 2950 μm or less.

[0145] The experimental results of Examples 1-9 and Comparative Examples 1-5 will be explained below. Figures 31 to 33 are diagrams showing the experimental results of Example 1. In Example 1, the type of lens 22 was M5018-VSW (manufactured by Computar), the length of the close-up ring 24 was 25 mm, the F-number was 1.8, the magnification was 0.51, the object-side NA was 0.094, the optical system was transmissive, and the gap was 450 μm.

[0146] Under these conditions, the experiment of Example 1 was performed. The amplitude of signal W22 was 24.178, the phase was -0.799 [px], and the period was 6.185 [px]. The amplitude of signal W21 was 27.027, the phase was -0.719 [px], and the period was 6.184 [px]. The amplitude ratio was 0.89, and the period difference in pixels was 0.001 [px]. Example 1 successfully focused various precision alignment marks.

[0147] 34 to 36 are diagrams showing the experimental results of Example 2. In Example 2, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 25 mm, the F-number was 1.8, the magnification was 0.51, the object-side NA was 0.094, the optical system was transmissive, and the gap was 2800 μm.

[0148] Under these conditions, the experiment of Example 2 was performed. The amplitude of signal W22 was 2.528, the phase was 0.286 [px], and the period was 6.162 [px]. The amplitude of signal W21 was 26.479, the phase was -0.470 [px], and the period was 6.187 [px]. The amplitude ratio was 0.10, and the period difference in pixels was 0.025 [px]. Example 2 successfully focused various precision alignment marks.

[0149] 37 to 39 are diagrams showing the experimental results of Comparative Example 1. In Comparative Example 1, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 25 mm, the F-number was 1.8, the magnification was 0.51, the object-side NA was 0.094, the optical system was transmissive, and the gap was 2850 μm.

[0150] Under these conditions, the experiment for Comparative Example 1 was performed. The signal W22 had an amplitude of 2.383, a phase of 0.500 [px], and a period of 6.129 [px]. The signal W21 had an amplitude of 26.479, a phase of -0.470 [px], and a period of 6.187 [px]. The amplitude ratio was 0.09, and the period difference in pixels was 0.058 [px]. Comparative Example 1 failed to focus various precision alignment marks.

[0151] 40 to 42 are diagrams showing the experimental results of Example 3. In Example 3, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 50 mm, the F-number was 1.8, the magnification was 1.01, the object-side NA was 0.140, the optical system was transmissive, and the gap was 450 μm.

[0152] Under these conditions, the experiment of Example 3 was performed. The amplitude of signal W22 was 33.254, the phase was 3.135 [px], and the period was 12.465 [px]. The amplitude of signal W21 was 30.337, the phase was 3.628 [px], and the period was 12.462 [px]. The amplitude ratio was 1.10, and the period difference per pixel was 0.003 [px]. Example 3 successfully focused various precision alignment marks.

[0153] 43 to 45 are diagrams showing the experimental results of Example 4. In Example 4, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 50 [mm], the F-number was 1.8, the magnification was 1.01, the object-side NA was 0.140, the optical system was transmissive, and the gap was 2900 [μm].

[0154] Under these conditions, the experiment of Example 4 was performed. The amplitude of signal W22 was 3.154, the phase was -1.939 [px], and the period was 12.453 [px]. The amplitude of signal W21 was 22.441, the phase was 1.835 [px], and the period was 12.473 [px]. The amplitude ratio was 0.14, and the period difference in pixels was 0.02 [px]. Example 4 successfully focused various precision alignment marks.

[0155] 46 to 48 are diagrams showing the experimental results of Example 5. In Example 5, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 50 [mm], the F-number was 1.8, the magnification was 1.01, the object-side NA was 0.140, the optical system was transmissive, and the gap was 2950 [μm].

[0156] Under these conditions, the experiment of Example 5 was performed. The amplitude of signal W22 was 2.256, the phase was -0.148 [px], and the period was 12.475 [px]. The amplitude of signal W21 was 25.868, the phase was -2.071 [px], and the period was 12.469 [px]. The amplitude ratio was 0.09, and the period difference in pixels was 0.006 [px]. Example 5 successfully focused various precision alignment marks.

[0157] 49 to 51 are diagrams showing the experimental results of Comparative Example 2. In Comparative Example 2, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 50 [mm], the F-number was 1.8, the magnification was 1.01, the object-side NA was 0.140, the optical system was transmissive, and the gap was 3050 [μm].

[0158] Under these conditions, the experiment for Comparative Example 2 was performed. The results showed that the amplitude of signal W22 was 0.935, the phase was -0.134 [px], and the period was 3.340 [px]. The amplitude of signal W21 was 25.697, the phase was -1.874 [px], and the period was 12.469 [px]. The amplitude ratio was 0.04, and the period difference in pixels was 9.129 [px]. Comparative Example 2 failed to focus various precision alignment marks.

[0159] 52 to 54 are diagrams showing the experimental results of Example 6. In Example 6, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 75 mm, the F-number was 1.8, the magnification was 1.53, the object-side NA was 0.168, the optical system was transmissive, and the gap was 450 μm.

[0160] Under these conditions, the experiment of Example 6 was performed. The amplitude of signal W22 was 19.293, the phase was 2.881 [px], and the period was 18.737 [px]. The amplitude of signal W21 was 23.960, the phase was 2.600 [px], and the period was 18.740 [px]. The amplitude ratio was 0.81, and the period difference in pixels was 0.003 [px]. Example 6 successfully focused various precision alignment marks.

[0161] 55 to 57 are diagrams showing the experimental results of Example 7. In Example 7, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 75 mm, the F-number was 1.8, the magnification was 1.53, the object-side NA was 0.168, the optical system was transmissive, and the gap was 1750 μm.

[0162] Under these conditions, the experiment of Example 7 was performed. The amplitude of signal W22 was 2.609, the phase was -4.421 [px], and the period was 18.734 [px]. The amplitude of signal W21 was 23.771, the phase was 2.308 [px], and the period was 18.736 [px]. The amplitude ratio was 0.11, and the period difference in pixels was 0.002 [px]. Example 7 successfully focused various precision alignment marks.

[0163] 58 to 60 are diagrams showing the experimental results of Comparative Example 3. In Comparative Example 3, the type of lens 22 was M5018-VSW, the length of the close-up ring 24 was 75 mm, the F-number was 1.8, the magnification was 1.53, the object-side NA was 0.168, the optical system was transmissive, and the gap was 1800 μm.

[0164] Under these conditions, the experiment for Comparative Example 3 was performed. The signal W22 had an amplitude of 33.254, a phase of 3.135 [px], and a period of 12.465 [px]. The signal W21 had an amplitude of 30.337, a phase of 3.628 [px], and a period of 12.462 [px]. The amplitude ratio was 0.10, and the period difference in pixels was 0.0087 [px]. Comparative Example 3 failed to focus various precision alignment marks.

[0165] 61 to 63 are diagrams showing the experimental results of Example 8. In Example 8, the type of lens 22 was LED-BD-NIR-M5, the F-number was 0.6, the magnification was 5.00, the object-side NA was 0.650, the optical system was transmissive, and the gap was 450 μm.

[0166] Under these conditions, the experiment of Example 8 was performed. The amplitude of signal W22 was 39.250, the phase was -3.695 [px], and the period was 59.917 [px]. The amplitude of signal W21 was 62.258, the phase was -0.691 [px], and the period was 59.923 [px]. The amplitude ratio was 0.63, and the period difference in pixels was 0.006 [px]. Example 8 successfully focused various precision alignment marks.

[0167] 64 to 66 are diagrams showing the experimental results of Example 9. In Example 9, the type of lens 22 was LED-BD-NIR-M5, the F-number was 0.6, the magnification was 5.00, the object-side NA was 0.650, the optical system was transmissive, and the gap was 700 μm.

[0168] Under these conditions, the experiment of Example 9 was performed. The amplitude of signal W22 was 8.382, the phase was 12.868 [px], and the period was 59.910 [px]. The amplitude of signal W21 was 63.732, the phase was 13.855 [px], and the period was 59.957 [px]. The amplitude ratio was 0.13, and the period difference in pixels was 0.047 [px]. Example 9 successfully focused various precision alignment marks.

[0169] 67 to 69 are diagrams showing the experimental results of Comparative Example 4. In Comparative Example 4, the type of lens 22 was LED-BD-NIR-M5, the F-number was 0.6, the magnification was 5.00, the object-side NA was 0.650, the optical system was transmissive, and the gap was 750 μm.

[0170] Under these conditions, the experiment for Comparative Example 4 was performed. The results showed that the amplitude of signal W22 was 3.351, the phase was 7.103 [px], and the period was 59.785 [px]. The amplitude of signal W21 was 62.684, the phase was 6.094 [px], and the period was 59.920 [px]. The amplitude ratio was 0.05, and the period difference in pixels was 0.135 [px]. Comparative Example 4 failed to focus various precision alignment marks.

[0171] 70 to 72 are diagrams showing the experimental results of Comparative Example 5. In Comparative Example 5, the type of lens 22 is OS-TCM1.0-H1.1-CEI, the F-number is 2.8, the magnification is 1.00, the object-side NA is 0.091, the optical system is reflective, and the gap is 450 μm.

[0172] Under these conditions, the experiment for Comparative Example 5 was performed. The results showed that the amplitude of signal W22 was 1.057, the phase was -1.226 [px], and the period was 12.050 [px]. The amplitude of signal W21 was 7.938, the phase was -1.862 [px], and the period was 6.076 [px]. The amplitude ratio was 0.13, and the period difference per pixel was 5.974 [px]. Comparative Example 5 failed to focus various precision alignment marks. [Explanation of symbols]

[0173] 1...alignment device, 20...camera, 22...lens, 30...fixed stage, 40...XYZθ axis movable stage, 50...illumination device, 100...control device, 110...communication interface, 120...input interface, 130...output interface, 140...storage unit, 150...processing unit, 151...acquisition unit, 152...image processing unit, 153...calculation unit, 154...output control unit, OB1...first object, OB2...second object

Claims

1. stacking a first object on which a first array having a first periodic structure is formed and a second object on which a second array having the first periodic structure is formed; irradiating the stacked first object and the stacked second object with light; detecting a first signal that is a signal of the light that has passed through the first array formed on the first object; detecting a second signal that is a signal of the light that has passed through the second array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal and the second signal; Including, the first array is formed on one of a first surface of the first object and a second surface opposite to the first surface, the second array is formed on one of a third surface of the second object and a fourth surface opposite to the third surface, the fourth surface being the surface that does not face the first object; Alignment method.

2. the first object further includes a third array having a second periodic structure different from the first periodic structure; a fourth array having the second periodic structure is further formed on the second object, detecting a third signal that is a signal of the light that has passed through the third array formed on the first object; detecting a fourth signal that is a signal of the light that has passed through the fourth array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal, the second signal, the third signal, and the fourth signal; Further comprising: the third array is formed on one of the first surface and the second surface of the first object, the fourth array is formed on one of the third surface and the fourth surface of the second object that does not face the first object; The alignment method according to claim 1 .

3. adjusting positions of the stacked first object and the stacked second object based on the calculated positional deviation; When the first object and the second object are stacked, the first array formed on the first object and the second array formed on the second object are formed so as not to overlap with each other. The alignment method according to claim 1 or 2.

4. the displacement between the first object and the second object is calculated using an optical system; the optical system includes: a stage that adjusts the positions of the first object and the second object in horizontal directions, vertical directions, and rotational directions on a horizontal plane; a light source that is disposed below the stage and irradiates the light; and a camera that is disposed above the stage and detects the light that has passed through the first object and the second object, The light is near-infrared light. The alignment method according to claim 1 or 2.

5. the displacement between the first object and the second object is calculated using an optical system; the optical system includes: a stage that adjusts the positions of the first object and the second object in horizontal directions, vertical directions, and rotational directions on a horizontal plane; a light source that is disposed inside the stage and irradiates the light; and a camera that is disposed above the stage and detects the light that has passed through the first object and the second object, The light is near-infrared light. The alignment method according to claim 1 or 2.

6. The distance between the first object and the second object that can be aligned is 2950 μm or less. The alignment method according to claim 4 .

7. When the distance between the first object and the second object is 1000 μm or more, the numerical aperture of the camera lens is 0.168 or less. The alignment method according to claim 4 .

8. The stacked first object and the second object are used to manufacture any one of an optical semiconductor element, a semiconductor element, and an optical element. The alignment method according to claim 1 or 2.

9. 1. A method for manufacturing a laminate including a first object and a second object, comprising: stacking the first object on which a first array having a first periodic structure is formed and the second object on which a second array having the first periodic structure is formed; irradiating the stacked first object and the stacked second object with light; detecting a first signal that is a signal of the light that has passed through the first array formed on the first object; detecting a second signal that is a signal of the light that has passed through the second array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal and the second signal; adjusting the positions of the stacked first object and the stacked second object based on the calculated positional deviation; Including, the first array is formed on one of a first surface of the first object and a second surface opposite to the first surface, the second array is formed on one of a third surface of the second object and a fourth surface opposite to the third surface, the fourth surface being the surface that does not face the first object; Manufacturing method.

10. the first object further includes a third array having a second periodic structure different from the first periodic structure; a fourth array having the second periodic structure is further formed on the second object, detecting a third signal that is a signal of the light that has passed through the third array formed on the first object; detecting a fourth signal that is a signal of the light that has passed through the fourth array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal, the second signal, the third signal, and the fourth signal; Further comprising: the third array is formed on one of the first surface and the second surface of the first object, the fourth array is formed on one of the third surface and the fourth surface of the second object that does not face the first object; The method of claim 9.

11. The laminate is used for manufacturing any one of an optical semiconductor element, a semiconductor element, and an optical element. The method according to claim 9 or 10.

12. A lithography method for transferring a pattern formed on one of a first object and a second object to the other, comprising: stacking a first object on which a first array having a first periodic structure is formed and a second object on which a second array having the first periodic structure is formed; irradiating the stacked first object and the stacked second object with light; detecting a first signal that is a signal of the light that has passed through the first array formed on the first object; detecting a second signal that is a signal of the light that has passed through the second array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal and the second signal; adjusting the positions of the stacked first object and the stacked second object based on the calculated positional deviation; Including, the first array is formed on one of a first surface of the first object and a second surface opposite to the first surface, the second array is formed on one of a third surface and a fourth surface facing the third surface of the second object, the surface not facing the first object; When the first array is formed as the pattern on the first object, transferring the first array formed on the first object to the second object; When the second array is formed as the pattern on the second object, the method further includes transferring the second array formed on the second object to the first object. Lithography methods.

13. the first object further includes a third array having a second periodic structure different from the first periodic structure; a fourth array having the second periodic structure is further formed on the second object, detecting a third signal that is a signal of the light that has passed through the third array formed on the first object; detecting a fourth signal that is a signal of the light that has passed through the fourth array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal, the second signal, the third signal, and the fourth signal; Further comprising: the third array is formed on one of the first surface and the second surface of the first object, the fourth array is formed on one of the third surface and the fourth surface of the second object that does not face the first object, When the first array and the third array are formed as the pattern on the first object, transferring the first array and the third array formed on the first object to the second object; When the second array and the fourth array are formed as the pattern on the second object, the second array and the fourth array formed on the second object are transferred to the first object. The lithographic method of claim 12.

14. a detection unit that detects a signal of light that is irradiated onto and transmitted through a first object and a second object that are stacked together, the first object having a first array element with a first periodic structure formed thereon and the second object having a second array element with the first periodic structure formed thereon; a calculation unit that calculates a positional deviation of the stacked first object and the stacked second object based on the signal, the detection unit detects a first signal that is a signal of the light that has passed through the first array formed on the first object, and a second signal that is a signal of the light that has passed through the second array formed on the second object, the calculation unit calculates the positional deviation based on the first signal and the second signal; the first array is formed on one of a first surface of the first object and a second surface opposite to the first surface, the second array is formed on one of a third surface of the second object and a fourth surface opposite to the third surface, the fourth surface being the surface that does not face the first object; Alignment device.

15. the first object further includes a third array having a second periodic structure different from the first periodic structure; a fourth array having the second periodic structure is further formed on the second object, the detection unit further detects a third signal that is a signal of the light that has passed through the third array formed on the first object, and a fourth signal that is a signal of the light that has passed through the fourth array formed on the second object, the calculation unit calculates the positional deviation between the stacked first object and the stacked second object based on the first signal, the second signal, the third signal, and the fourth signal; the third array is formed on one of the first surface and the second surface of the first object, the fourth array is formed on one of the third surface and the fourth surface of the second object that does not face the first object; The alignment device of claim 14.

16. A program to be executed by a computer, detecting a signal of light irradiated onto and transmitted through a first object and a second object stacked together, the first object having a first array having a first periodic structure formed thereon and the second object having a second array having the first periodic structure formed thereon; calculating a positional deviation between the stacked first object and the stacked second object based on the signal; detecting a first signal that is a signal of the light that has passed through the first array formed on the first object; detecting a second signal that is a signal of the light that has passed through the second array formed on the second object; calculating the positional deviation based on the first signal and the second signal; Including, the first array is formed on one of a first surface of the first object and a second surface opposite to the first surface, the second array is formed on one of a third surface of the second object and a fourth surface opposite to the third surface, the fourth surface being the surface that does not face the first object; program.

17. the first object further includes a third array having a second periodic structure different from the first periodic structure; a fourth array having the second periodic structure is further formed on the second object, detecting a third signal that is a signal of the light that has passed through the third array formed on the first object; detecting a fourth signal that is a signal of the light that has passed through the fourth array formed on the second object; calculating a positional deviation of the stacked first object and the stacked second object based on the first signal, the second signal, the third signal, and the fourth signal; Further comprising: the third array is formed on one of the first surface and the second surface of the first object, the fourth array is formed on one of the third surface and the fourth surface of the second object that does not face the first object; The program according to claim 16.

Images