Method for manufacturing periphery processed stacking wafer, method for manufacturing chip, and apparatus for processing stacking wafer

Abstract

To provide a method of manufacturing an outer periphery processed laminated wafer capable of suitably performing processing even if there is a bonding deviation between a first wafer and a second wafer when manufacturing the outer periphery processed laminated wafer by processing the outer periphery of the laminated wafer formed by laminating the second wafer on the first wafer.SOLUTION: The method includes a bonding deviation acquisition step of acquiring a value relating to bonding deviation between the first wafer and the second wafer by measuring a position of the outer peripheral portion, a first position acquisition step of acquiring a position of the first wafer with respect to the holding mechanism in a state where the stacked wafer is held by the holding mechanism, a second position acquisition step of acquiring a position of the second wafer with respect to the holding mechanism based on the value relating to the bonding deviation and the position of the first wafer, and a processing step of cutting the outer peripheral portion of the first wafer with reference to the position of the second wafer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an outer periphery-processed laminated wafer obtained by processing the outer periphery of a laminated wafer formed by stacking a second wafer on a first wafer, a method for manufacturing a chip, and a processing apparatus for processing the outer periphery of a laminated wafer. [Background technology]

[0002] Device chips mounted on electronic devices such as mobile phones and personal computers are manufactured by processing semiconductor wafers.

[0003] A plurality of planned dividing lines (streets) are set in a grid pattern on one surface of a disk-shaped semiconductor wafer, and devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), etc. are formed in each rectangular area defined by the planned dividing lines. The semiconductor wafer on which the devices are formed is cut along each planned dividing line, thereby dividing the semiconductor wafer into a plurality of device chips.

[0004] In recent years, wafers have been thinned in order to reduce the size and weight of device chips in the manufacture of such chips. For example, in the manufacturing process of device chips as described above, the backside of a wafer on which devices are formed is ground to thin the entire wafer.

[0005] In wafer manufacturing processes involving such thinning, stacked wafers are sometimes used, in which another wafer is bonded to the wafer to be processed as a support substrate to maintain the strength of the wafer after thinning. By performing a grinding process on the wafer to be processed (first wafer) bonded to the support substrate (second wafer), the first wafer is thinned while maintaining a thickness sufficient to maintain the strength of the entire stacked wafer.

[0006] When wafers are handled, such as transported and processed, their outer periphery is chamfered to prevent chipping during transport. When a chamfered wafer is ground and thinned, a thin, pointed shape called a knife edge is formed on the outer periphery of the wafer.

[0007] If a knife edge is formed on the outer periphery of a wafer, it is more likely to cause defects such as chipping of the wafer, so to prevent this, a process called edge trimming is performed to remove the chamfered portion on the outer periphery of the wafer before grinding the wafer. In this edge trimming, for example, a cutting blade is made to cut into the outer periphery of the wafer in a direction along the circumferential direction of the wafer, thereby removing the outer periphery of the wafer.

[0008] Patent Document 1, for example, describes a technique related to such wafer edge trimming.

[0009] In a laminated wafer formed by bonding a first wafer to a second wafer, edge trimming may be performed on the first wafer to be processed. Here, when the first and second wafers are bonded, their centers may be misaligned. When a first wafer of the same diameter is bonded to a second wafer with their centers misaligned, a portion of the outer periphery of the first wafer protrudes radially outward relative to the outer periphery of the second wafer.

[0010] In this state, for example, if the outer periphery of the first wafer is cut by a certain width, depending on the cutting width and the amount of misalignment between the first wafer and the second wafer, the portion of the first wafer that protrudes radially outward from the second wafer and its surroundings will remain unbonded to the second wafer.

[0011] If processing such as grinding or cutting is performed on the first wafer of a stacked wafer processed into such a shape, the portion of the first wafer that is not bonded to the second wafer will be processed without being supported by the second wafer, increasing the possibility of chipping or wafer cracking in this portion or its surrounding area. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-173961 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-96295 Summary of the Invention [Problem to be solved by the invention]

[0013] The object of the present invention is to provide a method for manufacturing a periphery-processed laminated wafer, a chip manufacturing method, and a laminated wafer processing device that can perform processing suitably even if there is a bonding misalignment between the first wafer and the second wafer when processing the periphery of a laminated wafer formed by stacking a second wafer on a first wafer to produce a periphery-processed laminated wafer. [Means for solving the problem]

[0014] According to one aspect of the present invention, there is provided a method for manufacturing a periphery-processed laminated wafer, in which a periphery-processed laminated wafer is manufactured by cutting the periphery of a first wafer from among laminated wafers formed by bonding one side of a first wafer and one side of a second wafer, each of which has a plate shape, to manufacture the laminated wafer, the method comprising the steps of: acquiring a value relating to a bonding misalignment between the first wafer and the second wafer by measuring the position of the periphery of the first wafer and the position of the periphery of the second wafer; holding the second wafer side of the laminated wafer on a holding surface of a holding mechanism; and There is provided a method for manufacturing a periphery-processed laminated wafer, which includes a first position acquisition process for acquiring the position of the first wafer relative to the holding mechanism while the laminated wafers are held by the holding mechanism after the step, a second position acquisition process for acquiring the position of the second wafer relative to the holding mechanism based on the value related to the bonding misalignment acquired in the bonding misalignment measurement process and the position of the first wafer acquired in the first position acquisition process, and a processing process for cutting the outer periphery of the first wafer using the position of the second wafer acquired in the second position acquisition process as a reference.

[0015] Preferably, the method uses a processing device equipped with a holding mechanism that rotates around a rotation axis extending in a direction intersecting the holding surface and a cutting blade that cuts into the stacked wafers held by the holding mechanism, and further includes a holding deviation acquisition process that acquires a value related to the deviation between the position of the rotation axis of the holding mechanism and the position of the center of the second wafer held by the holding mechanism, and in the processing process, the holding mechanism is rotated together with the stacked wafers held by the holding mechanism, and the outer periphery of the first wafer is cut while adjusting the position of the cutting blade relative to the holding mechanism according to the angle of the holding mechanism based on the value related to the deviation calculated in the holding deviation measurement process.

[0016] According to another aspect of the present invention, there is provided a laminated wafer processing device comprising: a first holding mechanism for holding an object; a detection unit for detecting the position of the outer periphery of the object held by the first holding mechanism from the outside in the radial direction of the object; a cutting blade for cutting into the object held by a second holding mechanism; and a controller for adjusting the relative positional relationship between the second holding mechanism and the cutting blade.

[0017] Preferably, the first retention mechanism and the second retention mechanism are the same retention mechanism.

[0018] According to yet another aspect of the present invention, there is provided a method for manufacturing a periphery-processed laminated wafer, in which a first wafer and a second wafer, each of which is plate-shaped, are laminated by bonding one side of the first wafer and one side of the second wafer together to produce a periphery-processed laminated wafer, the method comprising: a bonding deviation acquisition step of acquiring a value related to bonding deviation between the first wafer and the second wafer by measuring the position of the outer periphery of the first wafer and the position of the outer periphery of the second wafer; and a holding step of holding the second wafer side of the laminated wafer on a holding surface of a holding mechanism. There is provided a method for manufacturing a periphery-processed laminated wafer, which includes a first position acquisition process for acquiring the position of the first wafer relative to the holding mechanism while the laminated wafers are held by the holding mechanism after the holding process; a second position acquisition process for acquiring the position of the second wafer relative to the holding mechanism based on the value related to the bonding misalignment acquired in the bonding misalignment measurement process and the position of the first wafer acquired in the first position acquisition process; and a processing process for processing the outer periphery of the first wafer using the position of the second wafer acquired in the second position acquisition process as a reference.

[0019] According to yet another aspect of the present invention, there is provided a method for manufacturing a chip using the above-mentioned manufacturing method of a peripherally processed laminated wafer, which further includes a dividing step of dividing the first wafer to obtain chips after the processing step. [Effects of the Invention]

[0020] In a method for producing periphery-processed laminated wafers according to one aspect of the present invention, the periphery of a first wafer is cut using the center position of a second wafer as a reference.

[0021] In addition, in a laminated wafer processing device according to another aspect of the present invention, the position of the second wafer is acquired by a detector provided radially outward of the laminated wafers, which are the object.

[0022] As a result, the manufacturing method for a laminated wafer with outer periphery processing, the manufacturing method for a chip, and the processing apparatus for a laminated wafer of the present invention can perform processing suitably even if there is a bonding misalignment between the first wafer and the second wafer when processing the outer periphery of the laminated wafer. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing an example of a configuration of a laminated wafer processing device. [Figure 2] FIG. 2 is a side view showing a configuration of a part of the processing apparatus of FIG. [Figure 3] FIG. 3 is a flowchart illustrating an example of a procedure for manufacturing a periphery-processed laminated wafer and a method for manufacturing a chip. [Figure 4] FIG. 4(A) is a side view that schematically illustrates an example of how bonding misalignment in laminated wafers is measured, and FIG. 4(B) is a plan view of FIG. 4(A). [Figure 5] FIG. 5(A) is a side view that schematically illustrates another example of how bonding misalignment in laminated wafers is measured, and FIG. 5(B) is a plan view of FIG. 5(A). [Figure 6] FIG. 6 is a side view that schematically illustrates an example of how the position of the first wafer is measured. [Figure 7] FIG. 7(A) is a side view that schematically explains the bonding misalignment of laminated wafers, and FIG. 7(B) is a plan view of FIG. 7(A). [Figure 8] FIG. 8 is a side cross-sectional view that schematically illustrates an example of how laminated wafers are processed. [Figure 9]FIG. 9(A) is a side cross-sectional view showing an example of the configuration of a laminated wafer with its periphery processed, obtained by processing a laminated wafer, and FIG. 9(B) is a plan view of FIG. 9(A). [Figure 10] FIG. 10 is a cross-sectional side view for explaining another example of how laminated wafers are processed. [Figure 11] FIG. 11 is a cross-sectional side view for schematically explaining another stage in the processing of laminated wafers. [Figure 12] FIG. 12 is a cross-sectional side view illustrating a further stage in the processing of stacked wafers. [Figure 13] FIG. 13 is a side cross-sectional view for explaining an example of how a wafer is divided. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment of the present invention will be described with reference to the accompanying drawings.

[0025] First, a cutting device 2 according to a first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing an example of the configuration of the cutting device 2 as a laminated wafer processing device, and Figure 2 is a side view showing the configuration of a portion of the cutting device 2. Note that for convenience of drawing, Figure 1 shows some parts such as the cutting mechanism 12 in a simplified form.

[0026] 1 and 2, the X-axis, Y-axis, and Z-axis represent three mutually orthogonal directions in three-dimensional space. The XY plane defined by the X-axis and Y-axis is parallel to the horizontal plane, and the Z-axis is parallel to the vertical direction.

[0027] The cutting device 2 includes a base 4 that supports or houses each of the devices that make up the cutting device 2, a displacement measurement mechanism 8 for performing the bonding displacement measurement process described below on the laminated wafer 6 that is the object to be processed, a processing holding mechanism 10 that is a holding mechanism that holds the laminated wafer 6 during cutting processing, and a cutting mechanism 12 that cuts the laminated wafer 6.

[0028] The laminated wafer 6, which is the object to be processed by the cutting device 2, is, for example, a plate-shaped semiconductor wafer made of silicon, and is composed of a first wafer 6a and a second wafer 6b, each of which is plate-shaped, stacked on top of each other.

[0029] The first wafer 6a and the second wafer 6b are disk-shaped wafers of the same shape and material, and are bonded to each other on one side. Wafer bonding can be performed by various methods, such as using an adhesive, using intermolecular forces, or thermocompression bonding. Devices such as integrated circuits (ICs) and large-scale integration (LSIs) are formed on the side of the first wafer 6a that is not bonded to the second wafer 6b. In the cutting device 2 of this embodiment, the first wafer 6a of the stacked wafers 6 is the target for cutting (edge ​​trimming) its outer periphery (however, depending on the cutting operation, a portion of the second wafer 6b may also be cut).

[0030] In some cases, devices may be formed on the surface of the first wafer 6a that is to be bonded to the second wafer 6b.

[0031] The second wafer 6b is a so-called dummy wafer, such as an NP (Non Product) wafer or a QC (Quality Control) wafer, on which no devices are formed.

[0032] The first wafer 6a and the second wafer 6b, each of which is disk-shaped, are bonded together so that their centers coincide with each other as closely as possible, but depending on the accuracy of positioning during bonding, there may be a maximum deviation of, for example, 200 μm to 300 μm (bonding deviation). The cutting device 2 of this embodiment measures this bonding deviation, and based on the measured bonding deviation, cuts the first wafer 6a according to the procedure described below.

[0033] The base 4 is a frame that forms the base of the cutting device 2. A cover (not shown) that forms the top surface and multiple side surfaces of the cutting device 2 is provided on the top of the base 4, and a displacement measurement mechanism 8, a holding mechanism 10 during processing, and a cutting mechanism 12 are housed inside the cover.

[0034] The displacement measuring mechanism 8 includes a holding mechanism 14 during inspection, which is a holding mechanism for holding the stacked wafers 6, and a detection unit 16. The holding mechanism 14 during inspection includes a rotating table 14a and a positioning protrusion 14b.

[0035] The inspection holding mechanism 14 is a mechanism equivalent to a mechanism called a position table or the like provided in semiconductor processing equipment, etc. The rotating table 14a is a table on which the laminated wafer 6, which is the object, is placed, and is configured to rotate about an axis along the Z direction relative to the base 4. The rotation of the rotating table 14a is performed by a power mechanism such as a motor (not shown).

[0036] A plurality of positioning protrusions 14b are arranged around the turntable 14a so as to follow the periphery of the laminated wafers 6 placed on the turntable 14a. The positioning protrusions 14b are protrusions that protrude upward from the upper surface of the base 4. The plurality of positioning protrusions 14b are arranged on the upper surface of the base 4 so as to form a circle whose center is the position of the turntable 14a, and are configured to move in the radial direction while forming a circle with the same center.

[0037] When placing the stacked wafers 6 on the turntable 14a, the multiple positioning protrusions 14b are positioned in advance at a position far from the turntable 14a so that their diameter is larger than that of the stacked wafers 6, and in this state, the stacked wafers 6 are placed on the central turntable 14a.

[0038] A support table (not shown) is installed on the upper surface of the base 4 at a position adjacent to the inspection holding mechanism 14, and a cassette (not shown) carried in from outside the cutting device 2 is placed on this support table. A transfer mechanism (not shown), such as a robot arm, is installed at a position near the support table (not shown) and the inspection holding mechanism 14. The transfer mechanism (not shown) removes the laminated wafers 6 from the cassette supported by the support table and places them on the turntable 14a. The laminated wafers 6 are placed on the turntable 14a by this transfer mechanism (not shown).

[0039] Next, the positioning protrusions 14 b are moved radially inward so as to approach the rotating table 14 a , and the positioning protrusions 14 b come into contact with the outer periphery of the laminated wafers 6 .

[0040] The multiple positioning protrusions 14b move radially inward while maintaining a circular arrangement, and as the stacked wafers 6 move along with the movement of the positioning protrusions 14b, the stacked wafers 6 are positioned relative to the turntable 14a so that the center of the turntable 14a and the center of the stacked wafers 6 approximately coincide.

[0041] In this way, the holding mechanism 14 during inspection functions as a position table in the cutting device 2, and in addition, it plays a role in holding the stacked wafers 6 when measuring the bonding misalignment by the displacement measurement mechanism 8. The bonding misalignment is measured by the detection unit 16 with the stacked wafers 6 placed on the turntable 14a.

[0042] The detection unit 16 is, for example, an imaging device such as a camera with a lens, or a device such as a laser sensor, and is capable of measuring the distance between the detection unit 16 and an object. The object to be measured by the detection unit 16 is assumed to be the outer peripheries of the first wafer 6a and the second wafer 6b that constitute the laminated wafer 6 placed on the turntable 14a. Note that, in addition to a camera or a laser sensor, various devices having different mechanisms can be used as the detection unit 16 as long as they can suitably measure the distance to the object. The measurement of the bonding misalignment performed by the misalignment measurement mechanism 8 will be described in detail later.

[0043] The detection unit 16 is installed at a radially outer position of the stacked wafer 6 held on the turntable 14a, facing the side of the stacked wafer 6 (the surface forming the outer periphery of the disk), and is configured to measure the position of the outer periphery of the stacked wafer 6 from that position.

[0044] In this specification, the "periphery" of the wafer (stacked wafer 6, first wafer 6a and second wafer 6b) refers to the part that forms the outline of the wafer in a field of view when the wafer is viewed from a direction perpendicular to the plane of the plate-shaped wafer, and refers to the part that forms the side when the wafer is considered to be a short, cylindrical solid.

[0045] The stacked wafers 6 placed on the holding mechanism 14 during inspection are positioned relative to the base 4 by the positioning protrusions 14b, and the positions of the outer peripheries of the first and second wafers 6a, 6b are measured by the displacement measurement mechanism 8, before being transferred to the holding mechanism 10 during processing.

[0046] The stacked wafers 6 are moved from the holding mechanism during inspection 14 to the holding mechanism during processing 10 by a transfer mechanism 18 provided at a position on the upper surface of the base 4 near the holding mechanism during inspection 14 and the holding mechanism during processing 10. The transfer mechanism 18 is, for example, a robot arm.

[0047] The holding mechanism 10 during processing is, for example, a chuck table, and is configured to suck and hold the object, the laminated wafer 6. A rotation mechanism (not shown) that rotates the holding mechanism 10 during processing around a rotation axis along the Z direction (a rotation axis extending in a direction perpendicular to a holding surface 22a, which will be described later) is connected to the lower part of the holding mechanism 10 during processing.

[0048] An X-axis movement mechanism (not shown) that moves the holding mechanism 10 and the rotation mechanism along the X direction is provided below the holding mechanism 10. The X-axis movement mechanism is a mechanism that moves the spindle 26 to which the cutting blade 28 of the cutting mechanism 12 (described later) is attached and the holding mechanism 10 that holds the laminated wafers 6 relatively in the X direction, and in this embodiment, moves the holding mechanism 10 in the X direction.

[0049] It should be noted that the spindle 26 may be moved instead of the holding mechanism 10 during machining, or both the holding mechanism 10 during machining and the spindle 26 may be moved.

[0050] The holding mechanism 10 during processing, which is a chuck table, has a disk-shaped table base 20 made of metal or the like, and an adsorption plate 22 attached to the table base 20.

[0051] The suction plate 22 is a disk-shaped member made of, for example, porous ceramics. A disk-shaped recess corresponding to the dimensions of the suction plate 22 is formed in the upper part of the table base 20, and the suction plate 22 is fixed so as to fit into this recess. A flow path (not shown) is formed inside the table base 20, and one end of the flow path is connected to the underside of the suction plate 22.

[0052] The other end of the flow path provided in the table base 20 is connected to a suction source (not shown) such as an ejector, and when the suction source is operated, negative pressure supplied into the flow path acts on an object such as the stacked wafers 6 placed on the upper surface 22a of the suction plate 22. In this way, the upper surface 22a of the suction plate 22 functions as a holding surface that holds the stacked wafers 6. Note that the suction plate 22 may be, for example, a plate-like member made of metal or the like that has a plurality of holes that penetrate the suction plate 22 from top to bottom.

[0053] A cutting mechanism 12 is provided above the holding mechanism 10. The cutting mechanism 12 includes a spindle housing 24 and a spindle 26 housed in the spindle housing.

[0054] The spindle housing 24 is a hollow casing having an overall rectangular columnar shape, and is disposed so that its longitudinal direction is along the Y direction. As shown in Fig. 2, a part of the cylindrical spindle 26 is accommodated inside the spindle housing 24.

[0055] The cylindrical spindle 26 is housed in the spindle housing 24 with the axis of the cylinder aligned along the Y direction, and is adapted to rotate relative to the spindle housing 24 around the axis of the cylinder.

[0056] An annular cutting blade 28 is attached to one end of the spindle 26 that protrudes outward from the spindle housing 24. The cutting blade 28 is, for example, a hub-type blade, and has a disk-shaped base made of a metal such as aluminum and an annular cutting edge 28a provided along the outer periphery of the base.

[0057] The thickness of cutting edge 28a is greater than that of a blade used to divide a semiconductor wafer into chips, for example. The thickness of cutting edge 28a of cutting blade 28 is, for example, 1 mm or more and 3 mm or less.

[0058] A rotation drive source 30 such as a servo motor is connected to the other end of the spindle 26 , and the operation of the rotation drive source 30 causes the spindle 26 to rotate together with the cutting blade 28 .

[0059] The spindle housing 24 is supported by a Y-axis movement mechanism 32 and a Z-axis movement mechanism 42 so as to be movable relative to the base 4 in the Y and Z directions, respectively.

[0060] The Y-axis movement mechanism 32 and the Z-axis movement mechanism 42 are mechanisms that relatively move the spindle 26, to which the cutting blade 28 of the cutting mechanism 12 is attached, and the holding mechanism 10 that holds the laminated wafers 6, in the Y and Z directions, respectively, and in this embodiment, the spindle 26 is moved in the Z and Y directions. Note that instead of moving the spindle 26, the holding mechanism 10 may be moved, or both the holding mechanism 10 and the spindle 26 may be moved.

[0061] The Y-axis movement mechanism 32 includes a pair of guide rails 34 arranged along the Y direction on a frame constituting the cutting device 2, and a Y-axis movement table 36 slidably attached to the guide rails 34. A ball screw 38 is arranged between the pair of guide rails 34 along the Y direction.

[0062] A nut portion (not shown) provided on the back side of the Y-axis moving table 36 is rotatably connected to the ball screw 38. A rotary drive source 40 such as a pulse motor is connected to one end of the ball screw 38, and when the rotary drive source 40 operates to rotate the ball screw 38 around its axis, the Y-axis moving table 36 moves along the Y direction.

[0063] A Z-axis movement mechanism 42 is connected to the Y-axis movement table 36. The Z-axis movement mechanism 42 includes a pair of guide rails 44 arranged on the Y-axis movement table 36 along the Z direction, and a Z-axis movement table 46 slidably attached to the guide rails 44. A ball screw 48 is arranged between the pair of guide rails 44 along the Z direction.

[0064] The spindle housing 24 is fixed to the front surface of the Z-axis moving table 46. A nut portion (not shown) is provided on the back surface of the Z-axis moving table 46. A ball screw 48 is rotatably connected to the nut portion. A rotational drive source 50 such as a pulse motor is connected to the upper end of the ball screw 48. When the rotational drive source 50 operates to rotate the ball screw 48 about its own axis, the Z-axis moving table 46 moves along the Z-axis direction together with the spindle housing 24.

[0065] An imaging device 52, which is a camera, is attached to the Z-axis moving table 46 together with the spindle housing 24. The imaging device 52 is provided above the processing holding mechanism 10, and is configured to capture images of the laminated wafers 6 held by the processing holding mechanism 10, which is a chuck table, and input the captured image data to the controller 54 as a data signal.

[0066] The operation of each component of the cutting device 2, such as the deviation measurement mechanism 8, the holding mechanism during processing 10, the cutting mechanism 12, the transport mechanism 18, and the imaging device 52, is controlled by a controller 54. In particular, in the case of the cutting device 2 of this embodiment, the controller 54 has the function of acquiring values ​​relating to the positions of the first and second wafers 6a and 6b that make up the laminated wafer 6 according to the procedure described below, and cutting the laminated wafer 6 while adjusting the relative positional relationship between the holding mechanism during processing 10 and the cutting blade 28 based on these values.

[0067] The controller 54 is configured by a computer having a processor 54a, such as a central processing unit (CPU), and a memory 54b. The memory 54b includes a main storage device such as a dynamic random access memory (DRAM) and an auxiliary storage device such as a flash memory.

[0068] The auxiliary storage device stores software, and the functions of the controller 54 are realized by operating the processor 54a and other components in accordance with this software.

[0069] Measurement and processing of the laminated wafers 6 by the cutting device 2 will be described with reference to Fig. 3. Fig. 3 is a flowchart illustrating an example of a procedure for processing the outer peripheries of the laminated wafers 6 to manufacture outer periphery-processed laminated wafers.

[0070] The procedure shown in FIG. 3 includes a bonding process (step S10), a bonding deviation acquisition process (step S20), a detection deviation acquisition process (step S80), a holding process (step S30), a first position acquisition process (step S40), a second position acquisition process (step S50), a holding deviation acquisition process (step S60), a processing process (step S70), a peeling process (step S90), and a dividing process (step S100).

[0071] In the bonding step (step S10), one side of each of the plate-shaped first wafer 6a and second wafer 6b is bonded to each other to form a laminated wafer 6 (see FIG. 1).

[0072] The stacked wafers 6 thus formed are carried into the cutting device 2 and placed on the turntable 14a of the holding mechanism 14 during inspection, and a bonding deviation acquisition step (step S20) is performed by the deviation measurement mechanism 8. In the bonding deviation acquisition step, while the stacked wafers 6 are held by the holding mechanism 14 during inspection, the positions of the outer peripheries of the first wafer 6a and the second wafer 6b are measured, thereby acquiring a value related to the bonding deviation between the first wafer 6a and the second wafer 6b.

[0073] The value related to the joint misalignment is either the amount or the angle of the joint misalignment, or both, and can be obtained as, for example, the following values: Of course, various parameters other than the examples given here can be assumed as the value related to the joint misalignment.

[0074] (Amount of misalignment) The distance between the center of the first wafer 6a in a disk shape and the center of the second wafer 6b in a disk shape of the same diameter. The distance between the position of a particular part on the first wafer 6a and the position of the corresponding part on the second wafer 6b. In a plan view (a view perpendicular to the plane formed by the first and second wafers 6a and 6b), the maximum width of the portion of the outer periphery of the second wafer 6b, which has the same shape as the first wafer 6a, that protrudes from the outer periphery of the first wafer 6a.

[0075] (Direction of misalignment) When the stacked wafers 6 are held by the inspection holding mechanism 14 (placed on the rotating table 14a), the angle of the line connecting the centers of the first wafer 6a and the second wafer 6b relative to a virtual reference line. When the stacked wafers 6 are held by the holding mechanism 14 during inspection (placed on the turntable 14a), the orientation of the portion of the outer periphery of the second wafer 6b that protrudes the most from the outer periphery of the first wafer 6a relative to the turntable 14a. The angle of the line connecting the center of the first wafer 6a or the second wafer 6b and the position of the notch with respect to an imaginary reference line.

[0076] In the displacement measuring mechanism 8 of this embodiment, a value relating to the joining displacement is measured, for example, as follows.

[0077] Figures 4(A), 4(B) and 5(A), 5(B) are side views each illustrating a schematic example of how the amount of bonding misalignment in a laminated wafer 6 is measured, with Figures 4(A) and 5(A) being side views and Figures 4(B) and 5(B) being plan views.

[0078] For the sake of convenience, the thickness of each wafer and the bonding misalignment are exaggerated in Figures 4 and 5. This also applies to Figures 6 and onward.

[0079] 4(A) and 4(B) schematically show the measurement of bonding misalignment when, for example, the detection unit 16 is a microscope camera. When the detection unit 16 is a microscope camera, the relative positional relationship between the side surface of the laminated wafer 6 and the detection unit 16 can be grasped by utilizing the focal length of the microscope camera.

[0080] For example, a part of the side surface of the laminated wafer 6 can be imaged with a microscope camera or the like of the detection unit 16, and the focal length when the image is in focus can be used to determine the distance between the imaged area of ​​the side surface of the laminated wafer 6 and the detection unit 16. This is done while rotating the laminated wafer 6 on the turntable 14a, and the distance of the side surface of the laminated wafer 6 measured by the detection unit 16a is recorded while linking it to the angle of the turntable 14a, so that the position of each part of the side surface of the laminated wafer 6 with the turntable 14a at the center can be determined.

[0081] Since the stacked wafer 6 is composed of a first wafer 6a and a second wafer 6b stacked on top of each other, by performing the above measurements for the height at which the first wafer 6a is located and the height at which the second wafer 6b is located, the positions of each part of the side surfaces forming the outer periphery of each of the first wafer 6a and the second wafer 6b can be determined.

[0082] For example, if the first wafer 6a is disk-shaped, by acquiring the positions of multiple portions (three or more points) on its outer periphery, the position of its center can be identified in the form of coordinates or the like. The same applies to the second wafer 6b. This makes it possible to acquire the amount and direction of bonding misalignment between the first wafer 6a and the second wafer 6b. In addition, the positions of the outer peripheries and centers of the first wafer 6a and the second wafer 6b relative to the turntable 14a can also be acquired.

[0083] 5(A) and 5(B) schematically show the measurement of bonding misalignment when the detection unit 16 is, for example, a laser sensor. When the detection unit 16 is a laser sensor, the relative positional relationship between the side surface of the laminated wafer 6 and the detection unit 16 can be determined by the principles of, for example, triangulation, phase difference distance, or pulse propagation.

[0084] Using this, while rotating the turntable 14a in the same manner as described above, the angle of the turntable 14a and the distance between the side surfaces of the first wafer 6a and the second wafer 6b and the detection unit 16 are recorded, thereby making it possible to obtain values ​​such as the amount and direction of the bonding misalignment between the first wafer 6a and the second wafer 6b, the positions of the outer peripheries and centers of the first wafer 6a and the second wafer 6b relative to the turntable 14a, and the outer diameters of the first wafer 6a and the second wafer 6b.

[0085] Furthermore, in the example described here, a detection deviation acquisition step (step S80) is executed.

[0086] In the bonding deviation acquisition process (step S20), the detection unit 16, which is a laser sensor or the like, measures the positions of the detection unit 16 and each part of the side surface of the first and second wafers 6a, 6b to be measured, and based on this, values ​​related to the bonding deviation and values ​​such as the positions and dimensions of the first and second wafers 6a, 6b are acquired.

[0087] Here, due to temperature changes in the detection unit 16 itself, which is a laser or the like, or temperature changes in the structure supporting the stacked wafers 6, detection unit 16, etc., the dimensions and positional relationships of each part of the detection unit 16, the relative positional relationship between the detection unit 16 and the stacked wafers 6, etc., may change slightly, which may cause the distance between the detection unit 16 and the first and second wafers 6a and 6b to be measured to fluctuate.

[0088] Such fluctuations do not affect, for example, the amount of bonding misalignment (because bonding misalignment is grasped not as the distance from the detection unit 16 but as the relative positional relationship between the upper and lower wafers 6a, 6b), but may become a factor in measurement errors, for example, with regard to the outer diameter of the wafer.

[0089] In the procedure described here, in a processing step (step S70) executed later, for example, the outer periphery of the first wafer 6a is cut. At this time, the first wafer 6a is cut based on the position of the second wafer 6b, and it is desirable to accurately grasp the outer diameter of the second wafer 6b in order to correctly adjust the cutting width. However, when obtaining the outer diameter of the second wafer 6b, there is a possibility that a measurement error will occur for the reasons described above.

[0090] Therefore, in the detection deviation acquisition process (step S80), the distance between the side surface of the turntable 14a and the detection unit 16 is measured, and the position of the detection unit 16 relative to the inspection-in-holding mechanism 14 is acquired. In this way, deviation of the detection unit 16 from its fixed position due to temperature changes or the like is detected.

[0091] For example, when the distance between the detection unit 16 and each part on the side surface of the second wafer 6b is measured and the outer diameter of the second wafer 6b is calculated based on the distance, the deviation can be taken into consideration to more accurately calculate the outer diameter of the second wafer 6b. By using the outer diameter of the second wafer 6b calculated in this way in subsequent processes, more accurate processing becomes possible.

[0092] For convenience of explanation, in FIG. 3, the detection deviation acquisition process (step S80) is shown after the joining deviation process (step S20). However, the detection deviation acquisition process may be performed simultaneously with the joining deviation process, before the joining deviation acquisition process, or at any timing after the holding process (step S30) described next and before the processing process (step S70).

[0093] Once the values ​​relating to the bonding misalignment between the first wafer 6a and the second wafer 6b and the position of the detection unit 16 relative to the holding mechanism 14 during inspection have been acquired, the holding step (step S30) is then executed. The stacked wafers 6 held in the holding mechanism 14 during inspection are transferred to the holding mechanism 10 during processing by the transfer mechanism 18.

[0094] In the processing holding mechanism 10, which is a chuck table, the stacked wafer 6, which is formed by bonding a first wafer 6a and a second wafer 6b, is held in a position where the second wafer 6b side faces downward and is adsorbed onto the holding surface 22a, and the first wafer 6a side is exposed upward.

[0095] A first position acquisition step (step S40) is performed with the stacked wafers held by the holding mechanism 10 during processing. In the first position acquisition step, the position of the first wafer 6a among the stacked wafers 6 held by the holding mechanism 10 during processing is acquired based on the positions of multiple points on the outer periphery of the first wafer 6a.

[0096] The position of the first wafer 6a in this step is identified by an imaging device 52 arranged above the holding mechanism 10 during processing, as shown in Fig. 6. Fig. 6 is a side view that schematically illustrates an example of how the position of the first wafer 6a is measured.

[0097] The imaging device 52 acquires an image of at least a portion of the outer periphery of the stacked wafers 6 held by the processing holding mechanism 10 from above (a position away from the stacked wafers 6 in a direction perpendicular to the plane of the first wafer 6a), and inputs the image to the controller 54. If the first wafer 6a is disk-shaped (circular in plan view), the position of the center of the first wafer 6a can be identified by measuring the positions of at least three points on the outer periphery.

[0098] Furthermore, even if the first wafer 6a is not circular in plan view, if the shape and dimensions of the first wafer 6a are specified in advance, the position of the first wafer 6a relative to the processing holding mechanism 10 can be determined by measuring the positions of multiple points on the outer periphery that forms the outline of the first wafer 6a.

[0099] Here, since the stacked wafers 6 are held by the processing holding mechanism 10 in a position where the first wafer 6a side is exposed upward, it is easy to obtain an image of the first wafer 6a from above using the imaging device 52 and measure the position of an appropriate point on the outer periphery.

[0100] Subsequently, a second position acquisition step (step S50) is executed. In the second position acquisition step, the position of the second wafer 6b relative to the holding mechanism 10 during processing is acquired based on the value related to the bonding misalignment acquired in the previous bonding misalignment acquisition step (step S20) and the position of the first wafer 6a acquired in the previous first position acquisition step (step S40).

[0101] 7(A) and 7(B) are diagrams for explaining the bonding misalignment of the stacked wafers 6, with FIG. 7(A) being a side view and FIG. 7(B) being a plan view. The bonding misalignment between the first wafer 6a and the second wafer 6b is equivalent to the difference between the center position of the first wafer 6a and the center position of the second wafer 6b, as shown in FIG. 7(B). Therefore, if values ​​related to the bonding misalignment can be obtained in addition to the center position of the first wafer 6a, the center position of the second wafer 6b can be identified based on these values.

[0102] For example, if a stacked wafer 6 is formed by first and second wafers 6a and 6b that are disk-shaped and have the same diameter, and the positional deviation (amount and direction of bonding deviation) of the center of the second wafer 6b relative to the center of the first wafer 6a is acquired in the bonding deviation acquisition process, and the position coordinates of the center of the first wafer 6a are acquired in the first position acquisition process, the position of the second wafer 6b can be calculated as the position coordinates of the center of the second wafer 6b by adding or subtracting an amount related to the bonding deviation to the position coordinates of the center of the first wafer 6a.

[0103] Here, the amount and direction of the bonding misalignment in the stacked wafers 6 are measured by the inspection holding mechanism 14 of the misalignment measurement mechanism 8, and then the stacked wafers 6 are moved from the inspection holding mechanism 14 to the processing holding mechanism 10 by the transport mechanism 18.However, unless an unpredictable positional shift or rotation occurs in the stacked wafers 6 during transport, the data regarding the bonding misalignment acquired on the inspection holding mechanism 14 can be used without any problems in the second position acquisition process.

[0104] In addition, instead of determining the position of the second wafer 6b using such a mechanism, it may be possible in some cases to image a portion of the outer periphery of the second wafer 6b using, for example, an imaging device 52, and determine the position of the center of the second wafer 6b (see Patent Document 2 above).

[0105] However, the second wafer 6b is located behind the first wafer 6a as viewed from the imaging device 52. Therefore, when the amount of bonding misalignment is small, the outer periphery of the second wafer 6b is blocked by the first wafer 6a and is not sufficiently exposed in the field of view of the imaging device 52, which may cause problems such as the inability to identify the center position of the second wafer 6b or, even if it can be identified, insufficient accuracy.

[0106] As described above, the procedure of identifying the position of the first wafer 6a using the image acquired by the imaging device 52 and then identifying the position of the second wafer 6b by taking into account the bonding misalignment measured using the detection unit 16 makes it possible to obtain the position of the second wafer 6b more reliably and accurately.

[0107] Once the position of the second wafer 6b relative to the holding mechanism 10 during processing has been identified, a holding deviation acquisition step (step S60) is performed to measure the positional deviation of the second wafer 6b relative to the holding mechanism 10 during processing.

[0108] When the stacked wafers 6 are carried into the cutting device 2, the stacked wafers 6 are first placed on the turntable 14a of the holding mechanism for inspection 14, which is a position table, where they are positioned by the positioning protrusions 14b, and then transferred to the holding mechanism for processing 10 by the transfer mechanism 18. Therefore, unless an unexpected deviation occurs in the position or angle of the stacked wafers 6 during transport by the transfer mechanism 18, the stacked wafers 6 are positioned to a certain extent relative to the holding mechanism for processing 10 when they are held by the holding mechanism for processing 10.

[0109] However, positioning using the positioning protrusions 14b as described above cannot be expected to provide a very high degree of accuracy in positioning the stacked wafers 6. In addition, as described above, there may be a bonding misalignment between the first wafer 6a and the second wafer 6b in the stacked wafers 6.

[0110] Therefore, when the laminated wafers 6 are held by the holding mechanism 10 during processing, which is a chuck table, the positions of the laminated wafers 6 and the second wafer 6b relative to the holding mechanism 10 during processing are not precisely adjusted each time.

[0111] Meanwhile, in the processing step (step S70) executed later, the cutting blade 28 comes into contact with the stacked wafers 6 rotating together with the processing-holding mechanism 10, thereby cutting the stacked wafers 6. Therefore, the position of the second wafer 6b relative to the processing-holding mechanism 10 can affect the cutting position relative to the stacked wafers 6 during cutting.

[0112] If the rotation axis of the holding mechanism 10 and the central axis of the disk-shaped second wafer 6b coincide, symmetrical processing can be performed about the central axis of the second wafer 6b by positioning the cutting blade 28 at a fixed position relative to the holding mechanism 10 while rotating the holding mechanism 10. On the other hand, if the rotation axis of the holding mechanism 10 and the central axis of the second wafer 6b are misaligned, the relative positions of the holding mechanism 10 and the cutting blade 28 must be adjusted as the holding mechanism 10 rotates in order to perform symmetrical processing about the central axis of the second wafer 6b.

[0113] Therefore, in the holding deviation acquisition process (step S60), a value relating to the deviation between the position of the rotation axis of the processing holding mechanism 10 and the center position of the second wafer 6b held by the processing holding mechanism 10 is acquired in order to perform processing in the subsequent processing process taking into account the position of the second wafer 6b relative to the processing holding mechanism 10.

[0114] The "value related to deviation" acquired here is, for example, the following value, but values ​​other than the examples given here may also be acquired as the "value related to deviation". The difference between the position coordinate of the center of the second wafer 6b acquired in the previous second position acquisition step (step S50) and the position coordinate of the rotation axis of the holding mechanism 10 during processing. The distance and orientation of the center position of the second wafer 6b relative to the position of the rotation axis of the holding mechanism 10 during processing. The position coordinates of the center of the second wafer 6b acquired in the previous second position acquisition step.

[0115] 8 is a cross-sectional side view that schematically illustrates an example of how the laminated wafers 6 are cut.

[0116] In the processing step, first, the cutting blade 28 is positioned away from the stacked wafers 6 in the X direction, the Z direction, or both, and in the Y direction so that the outer periphery of the first wafer 6a and the cutting blade 28 overlap each other.

[0117] The cutting blade 28 rotates together with the spindle 26 around a rotation axis along the Y direction, and the stacked wafers 6 rotate together with the holding mechanism 10 during processing around a rotation axis along the Z direction.

[0118] While the cutting blade 28 and the stacked wafers 6 are rotating, they approach each other relatively in the X direction, the Z direction, or both. When they come into contact with each other, cutting of the stacked wafers 6 begins as shown in FIG.

[0119] The cutting blade 28 cuts into the outer periphery of the first wafer 6a located on the upper side of the stacked wafers 6, and cuts this portion. At this time, the controller 54 cuts the outer periphery of the first wafer 6a based on the position (center coordinates) of the second wafer 6b acquired in the second position acquisition step, rather than the position of the first wafer 6a.

[0120] For example, when cutting the outer periphery of a first wafer 6a that is disk-shaped with a radius r before cutting to obtain a first wafer 6a with a radius rd, the first wafer 6a is cut to a position that is a distance rd from the coordinates of the center of the first wafer 6a, or, rather than cutting the outer periphery of the first wafer 6a by a width d, the first wafer 6a is cut to a position that is a distance rd from the coordinates of the center of a second wafer 6b.

[0121] As described above, misalignment (bonding misalignment) may occur between the first wafer 6a and the second wafer 6b depending on the precision of the bonding process (see FIG. 7). If the outer periphery of the first wafer 6a is cut using the position of the first wafer 6a itself as a reference while there is such misalignment, the original misalignment will remain between the center positions of the first wafer 6a and the second wafer 6b after cutting.

[0122] Depending on the amount of misalignment, it is possible that a portion of the outer periphery of the first wafer 6a after cutting that is not bonded to the second wafer 6b may remain uncut. The outer peripheries of the first and second wafers 6a, 6b are chamfered, and these portions are not bonded to each other. If the outer periphery of the first wafer 6a is cut based on the position of the first wafer 6a, and the position of the second wafer 6b is misaligned with respect to the first wafer 6a, this unbonded portion is likely to remain.

[0123] If grinding or the like of the first wafer 6a is performed while an unbonded portion remains on the outer periphery of the first wafer 6a, the unbonded portion will be subjected to the grinding process without being supported by the second wafer 6b, which increases the possibility of chipping of the chip or cracking of the wafer in this portion or its surrounding area.

[0124] Therefore, in the cutting device 2 of this embodiment, in the processing step (step S70), the outer periphery of the first wafer 6a is cut using the position of the second wafer 6b as a reference.

[0125] Figure 9(A) is a side cross-sectional view showing an example of the shape of an outer periphery processed laminated wafer 56 obtained by processing the laminated wafer 6 (cutting the first wafer 6a), and Figure 9(B) is a plan view of Figure 9(A).

[0126] In the figure, the solid lines indicate the contours of the first and second wafers 6a and 6b after cutting. The dashed line indicates the contour of the first wafer 6a before cutting. The broken line indicates the contour of the first wafer 6a when the outer periphery of the first wafer 6a is cut based on the center position of the first wafer 6a.

[0127] As shown by the dashed line in Figure 9(B), if the outer periphery of the first wafer 6a is cut based on the center position of the first wafer 6a, the bonding misalignment between the first wafer 6a and the second wafer 6b will be preserved, and as a result, there is a possibility that an unbonded area will remain around the part indicated by the arrow in the figure.

[0128] In contrast, if the outer periphery of the first wafer 6a is cut based on the center position of the second wafer 6b, as shown by the solid line, the first wafer 6a is cut symmetrically with respect to the center of the second wafer 6b, thereby reducing the possibility that an unbonded area will remain on the outer periphery after cutting.

[0129] Furthermore, during cutting, the controller 54 cuts the outer periphery of the first wafer 6a while adjusting the position of the cutting blade 28 relative to the processing holding mechanism 10 in accordance with the angle of the processing holding mechanism 10 based on the value of the deviation obtained in the previous holding deviation measurement process (step S60).

[0130] If there is a deviation between the rotation axis of the in-process holding mechanism 10 and the center position of the second wafer 6b, the distance between the rotation axis and the outer periphery of the second wafer 6b will vary depending on the location. Therefore, when performing cutting while rotating the in-process holding mechanism 10, the controller 54 controls the Y-axis movement mechanism 32 to move the cutting blade 28 according to the rotation angle of the in-process holding mechanism 10 so that the cutting blade 28 is moved away from the rotation axis when cutting the outer periphery of the second wafer 6b that is far from the rotation axis of the in-process holding mechanism 10, and the cutting blade 28 is moved closer to the rotation axis when cutting the outer periphery of the second wafer 6b that is close to the rotation axis.

[0131] By doing this, even if there is a misalignment between the rotation axis of the processing holding mechanism 10 and the position of the center of the second wafer 6b, processing can be performed symmetrically about the center of the second wafer 6b, using the position of the second wafer 6b as a reference.

[0132] 3, a detection deviation acquisition step (step S80) is executed in addition to the bonding deviation acquisition step (step S20). In the processing step (step S70) described above, when the outer periphery of the wafer (first wafer 6a) is cut, an annular region that is radially inward by a width d is cut from the outer periphery of a circle of radius r as a reference to obtain an outer periphery-processed laminated wafer of a predetermined diameter (radius=rd).

[0133] At this time, the first wafer 6a is cut based on the position of the second wafer 6b, and at that time, the cutting width d must be set based on the outer diameter (radius = r) of the second wafer 6b to obtain the first wafer 6a with the desired diameter (radius = rd).

[0134] In order to appropriately set the cutting width d, it is necessary to accurately grasp the diameter (radius r) of the second wafer 6b. In the above-mentioned detection deviation acquisition step (step S80), the distance between the turntable 14a and the detection unit 16 is measured to grasp the positional relationship between the inspection holding mechanism 14 and the detection unit 16. This allows for detection of deviation from the fixed position of the detection unit 16 due to temperature changes, etc., and by taking this into consideration, the diameter of the second wafer 6b can be accurately calculated. Based on this, an appropriate value can be set as the cutting width d, and the first wafer 6a can be appropriately cut to the predetermined radius rd.

[0135] By the above steps, it is possible to manufacture a laminated wafer 56 with its periphery processed as shown by the solid lines in FIGS. 9(A) and 9(B).

[0136] In the processing step (step S70), processing other than cutting with a blade as described above can also be performed on the laminated wafers. Figure 10 is a side cross-sectional view that schematically explains another example of processing the laminated wafers 6, showing modification by laser processing.

[0137] For the laser processing, for example, a laser processing device 58 as shown in Fig. 10 is used. The laser processing device 58 includes an irradiation unit 60 that irradiates the laminated wafers 6 with a laser beam, and a holding mechanism 62 that holds the laminated wafers 6.

[0138] The irradiation unit 60 is a mechanism that guides and focuses a laser beam emitted from a laser oscillator (not shown) through an optical system including optical elements such as lenses and mirrors (not shown), and irradiates the laser beam onto the stacked wafer 6 held by the holding mechanism 62.

[0139] The holding mechanism 62 is, for example, a chuck table, and is configured to hold the stacked wafers 6 as an object by suction. An upper surface 62a of the holding mechanism 62 forms a holding surface that holds the stacked wafers 6. A negative pressure is supplied to the holding surface (upper surface) 62a from a suction source (not shown), thereby adsorbing the stacked wafers 6 as an object onto the holding surface 62a. A rotation mechanism (not shown) that rotates the holding mechanism 62 around a rotation axis along the vertical direction is connected to the lower part of the holding mechanism 62.

[0140] During modification, the stacked wafers 6 are held on the holding surface 62a of the holding mechanism 62, and a laser beam having a wavelength that is not easily absorbed by the first wafer 6a of the stacked wafers 6 (a wavelength that passes through the material of the first wafer 6a) is irradiated. The laser beam is adjusted by a condenser lens provided in the irradiation unit 60 to have a focal point at a target position on the first wafer 6a, and then irradiated.

[0141] 10, a laser beam is irradiated onto the outer periphery of the first wafer 6a located below from an irradiation unit 60 located above a holding mechanism 62. As the laser beam is irradiated, the holding mechanism 62 rotates, and the first wafer 6a is irradiated with the laser beam in a circular pattern.

[0142] Inside the first wafer 6a irradiated with the laser beam (near the focal point), a modified layer 64 is formed in an annular shape radially outward of the central region where the device is provided so as to surround the central region.

[0143] The laser beam may be split by an optical element such as a DOE (Diffractive Optical Element) or an LCoS (Liquid Crystal On Silicon) and then irradiated onto the first wafer 6a.

[0144] The modified layer refers to a region where the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding base material. Specific examples of the modified layer include a melt-treated region, a region with cracks, a region with dielectric breakdown, a region with a refractive index different from that of other regions, and a region where these regions are mixed. For example, the mechanical strength of the modified layer is lower than that of the surrounding region.

[0145] In this way, a periphery-processed laminated wafer is manufactured in which the periphery of the first wafer 6a constituting the laminated wafer 6 is processed by laser modification.

[0146] Next, the outer periphery-processed laminated wafers 6 are subjected to a grinding process to thin the laminated wafers 6. Figures 11 and 12 are side cross-sectional views each illustrating a different stage in the processing of the laminated wafers, showing how the outer periphery-processed laminated wafers 56 are ground.

[0147] As shown in Figures 10 to 12, when the outer periphery of the first wafer 6a is processed by thinning following laser modification, a laminated wafer 6 (outer periphery processed laminated wafer 56) formed in such a manner that, for example, a device is formed on the surface of the first wafer 6a that is bonded to the second wafer 6b (i.e., the surface on which the device is formed is bonded to the second wafer 6b) is used as the workpiece.

[0148] 10 and 11, the first wafer 6a is ground from the back surface 4b side. The grinding device 66 includes a grinding unit 68 and a holding mechanism .

[0149] The grinding unit 68 includes a spindle 74 to which a grinding wheel 72 is attached, and a housing 76 that rotatably supports the spindle 74. The spindle 74 is formed in a cylindrical shape and is supported within the housing 76 with its axis aligned vertically. A wheel mount to which the grinding wheel 72 is attached is provided at the lower end of the spindle 74, and a rotational drive source such as a motor (not shown) is attached to the upper end of the spindle 74.

[0150] The grinding wheel 72 is a disk-shaped component with multiple grinding stones 72a attached circumferentially to one side. The grinding wheel 72 is attached to a wheel mount at the lower end of the spindle 74 so that the surface on which the grinding stones 72a are attached faces downward. When a rotational drive source (not shown) attached to the spindle 74 is activated, the spindle 74 rotates together with the grinding wheel 72 around its axis that is aligned vertically.

[0151] The holding mechanism 70 is, for example, a chuck table, and is configured to hold the stacked wafers 6 as an object by suction. An upper surface 70a of the holding mechanism 70 forms a holding surface that holds the stacked wafers 6. A negative pressure is supplied to the holding surface 70a from a suction source (not shown), thereby adsorbing the stacked wafers 6 as an object onto the holding surface 70a. A rotation mechanism (not shown) that rotates the holding mechanism 70 around a rotation axis along the vertical direction is connected to the lower part of the holding mechanism 70.

[0152] A nozzle (working fluid supply unit) (not shown) is provided near the holding surface 70a, and the nozzle supplies a working fluid such as water required for polishing. The working fluid may be supplied through a flow path (not shown) provided inside the grinding unit 68, for example.

[0153] During grinding, as shown in FIG. 11, the stacked wafers 6 are held by the holding mechanism 70 so that the back surface of the first wafer 6a faces upward (towards the grinding unit 68) and the second wafer 6b contacts the holding surface 70a.

[0154] With the spindle 74 positioned above the holding mechanism 70, the spindle 74 rotates together with the grinding wheel 72 about a rotation axis oriented along the vertical direction, while the holding mechanism 70 rotates together with the stacked wafers 6 about a rotation axis oriented along the vertical direction. When the grinding wheel 72 comes into contact with the first wafer 6a, the first wafer 6a is ground from its back surface (top surface). During grinding, a liquid such as water is supplied as a processing liquid from the above-mentioned nozzle (processing liquid supply unit, not shown) as needed.

[0155] As the grinding progresses and the position of the back surface of the first wafer 6a reaches the modified layer 64 formed on the first wafer 6a or a crack extending from the modified layer 64, the area of ​​the first wafer 6a located radially outside the modified layer 64 is removed, as shown in Figure 12.

[0156] Furthermore, the first wafer 6a may be thinned by a method other than grinding using the grinding device 66 as described herein, such as cutting using a cutting device. The cutting device includes, for example, a cutting unit and a holding mechanism.

[0157] The cutting unit includes a spindle to which a cutting blade is attached and a housing that rotatably supports the spindle. The cutting blade includes, for example, an annular base and an annular cutting edge attached along the outer periphery of the base.

[0158] The spindle is cylindrical, has one end equipped with a blade mount to which the cutting blade is attached, and has the other end equipped with a rotational drive source such as a motor. The cylindrical spindle is housed in a housing with its axis aligned horizontally, and when the rotational drive source is activated, it rotates together with the cutting blade around the horizontal axis.

[0159] During cutting, the stacked wafers 6 are held by a holding mechanism so that the back surface of the first wafer 6a faces upward (toward the cutting unit), and the cutting blade cuts into the first wafer 6a from the back surface while rotating together with the spindle. While the cutting blade cuts into the first wafer 6a, the cutting unit and the holding mechanism move relatively in a direction along the holding surface, thereby thinning the first wafer 6a from the back surface.

[0160] When the thinning causes the rear surface of the first wafer 6a to reach the modified layer 64 formed on the first wafer 6a or a crack extending from the modified layer 64, the area located outside the modified layer 64 is removed.

[0161] When chips are manufactured from the periphery-processed laminated wafer 56 in which the periphery of the first wafer 6a has been processed as described above, a peeling step (step S90) is performed following the processing step (step S70). In the peeling step, the first wafer 6a is peeled from the second wafer 6b by, for example, ultrasonic processing, supplying a fluid such as water to the joint between the first and second wafers 6a, 6b, or applying an external force.

[0162] The peeled first wafer 6a is subjected to a dividing process to divide the first wafer 6a into chips (dividing process; step S100). FIG. 13 is a side cross-sectional view that schematically explains an example of how the wafer is divided. The dividing step can be carried out using a laser processing device 58 equipped with an irradiation unit 60 and a holding mechanism 62, for example, in the same manner as in the modification process (see FIG. 10).

[0163] In the example shown here, after the peeling step (step S90), the first wafer 6a is replaced with a tape 80 attached to the frame 78.

[0164] The frame 78 is, for example, a plate-like member formed into a ring shape using a material such as metal, with a hole formed in the center. A tape 80 having an adhesive layer on one side is attached to this hole. The tape 80 is a circular resin sheet with an adhesive layer made of an adhesive or the like on one side, and its outer periphery is attached to the frame 78. The surface of the first wafer 6a (the surface on which devices are formed) is attached to the center of the tape 80.

[0165] In the dividing step (step S100), a laser beam is irradiated from the irradiation unit 60 onto the first wafer 6a held by the holding mechanism 62 of the laser processing device 58. The irradiated laser beam has a wavelength that is absorbed by the material of the first wafer 6a. Here, the wavelength of the laser beam irradiated onto the first wafer 6a in the dividing step may differ from the wavelength of the laser beam irradiated onto the first wafer 6a in the previous modification step (processing step; step S70). In such cases, an irradiation unit and laser processing device different from those used for modification are often used in the dividing step. However, since the mechanism and appearance of the device are the same, the following description will use the reference numerals in FIG. 10, which were referenced in the description of modification.

[0166] While the first wafer 6a is being irradiated with the laser beam, the holding mechanism 62 and the irradiation unit 60 move relatively in a direction along the holding surface 62a, whereby the first wafer 6a is subjected to ablation processing along the planned dividing lines. In this way, the first wafer 6a is divided into individual chips, and the chips are manufactured.

[0167] In the dividing process (step S100), a groove may be formed in the first wafer 6a along the intended dividing line by laser ablation processing, and then the first wafer 6a may be divided along the groove, or a modified layer may be formed in the material of the first wafer 6a along the intended dividing line by irradiation with a laser beam, and then the first wafer 6a may be divided along the modified layer.

[0168] Alternatively, the dividing step (step S100) may be performed using a cutting device, such as the cutting device mentioned in the description of thinning the first wafer 6a in the processing step (step S70).

[0169] During cutting, the cutting blade cuts into the first wafer 6a held by the holding mechanism while rotating together with the spindle. While the cutting blade cuts into the first wafer 6a, the cutting unit and the holding mechanism move relatively in a direction along the holding surface, thereby dividing the first wafer 6a along the planned dividing line. After the cutting blade forms a cutting groove along the planned dividing line in the first wafer 6a, the first wafer 6a' may be divided along the cutting groove by a method such as applying an external force.

[0170] In addition to the above-described steps, other steps such as polishing, cleaning, ultraviolet irradiation, and film formation may be added as appropriate to the manufacturing of wafers with periphery processing and chips.

[0171] In the above embodiment, the inspection holding mechanism 14 that holds the stacked wafers 6 when measuring the bonding misalignment and the processing holding mechanism 10 that holds the stacked wafers 6 during processing are described as separate mechanisms, but the same holding mechanism may serve as both the inspection holding mechanism and the processing holding mechanism.

[0172] In this case, for example, with the stacked wafers held on a holding mechanism that is a chuck table, the bonding misalignment is measured by a detector provided around the holding mechanism, and cutting is performed on the stacked wafers held on the holding mechanism based on the data obtained by the measurement. In this case, it is also possible to omit the imaging device that obtains images from above the holding mechanism, and measure the position of the first wafer by a detector provided on the side of the holding mechanism.

[0173] In addition, the configurations of the workpiece and processing device described above may be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0174] 2: Processing equipment (cutting equipment), 4: Base 6: stacked wafer, 6a: first wafer, 6b: second wafer 8: Deviation measurement mechanism, 10: Holding mechanism during processing (chuck table), 12: Cutting mechanism 14: Holding mechanism during inspection, 14a: Rotating table, 14b: Positioning protrusion 16: detection unit, 18: transport mechanism 20: table base, 22: suction plate, 22a: holding surface (upper surface) 24: spindle housing, 26: spindle, 28: cutting blade, 28a: cutting edge 30: Rotation drive source 32: Y-axis moving mechanism, 34: guide rail, 36: Y-axis moving table 38: Ball screw, 40: Rotation drive source 42: Z-axis movement mechanism, 44: guide rail, 46: Z-axis movement table 48: Ball screw, 50: Rotation drive source 52: Imaging device 54: Controller, 54a: Processor, 54b: Memory 56: Outer periphery processed stacked wafer 58: laser processing device, 60: irradiation unit, 62: holding mechanism, 62a: holding surface (upper surface) 64: Modified layer 66: Grinding device, 68: Grinding unit, 70: Holding mechanism, 70a: Holding surface (upper surface) 72: Grinding wheel, 72a: Grinding stone, 74: Spindle, 76: Housing 78: Frame, 80: Tape

Claims

1. A method for manufacturing a periphery-processed laminated wafer, in which a periphery-processed laminated wafer is manufactured by cutting an outer periphery of a first wafer among laminated wafers formed by bonding one side of a first wafer and a second wafer each having a plate shape, a bonding misalignment acquisition step of acquiring a value related to bonding misalignment between the first wafer and the second wafer by measuring the position of an outer periphery of the first wafer and the position of an outer periphery of the second wafer; a holding step of holding the second wafer side of the stacked wafers on a holding surface of a holding mechanism; a first position acquiring step of acquiring a position of the first wafer relative to the holding mechanism while the stacked wafers are held by the holding mechanism after the holding step; a second position acquiring step of acquiring a position of the second wafer relative to the holding mechanism based on the value related to the bonding deviation acquired in the bonding deviation measuring step and the position of the first wafer acquired in the first position acquiring step; a processing step of cutting the outer periphery of the first wafer using the position of the second wafer acquired in the second position acquisition step as a reference; A method for manufacturing a periphery-processed laminated wafer comprising the steps of:

2. the holding mechanism that rotates about a rotation axis that extends in a direction intersecting the holding surface; a cutting blade that cuts into the stacked wafers held by the holding mechanism, a holding deviation acquiring step of acquiring a value relating to a deviation between the position of the rotation axis of the holding mechanism and the position of the center of the second wafer held by the holding mechanism, In the processing step, rotating the holding mechanism together with the stacked wafers held by the holding mechanism; cutting the outer periphery of the first wafer while adjusting the position of the cutting blade relative to the holding mechanism in accordance with the angle of the holding mechanism based on the value related to the deviation calculated in the holding deviation measuring step; The method for producing the periphery-processed laminated wafers according to claim 1.

3. a first holding mechanism that holds an object; a detection unit that detects the position of an outer periphery of the object held by the first holding mechanism from the outside in a radial direction of the object; a cutting blade that cuts into the object held by the second holding mechanism; a controller that adjusts the relative positional relationship between the second holding mechanism and the cutting blade; A laminated wafer processing device comprising:

4. 4. The laminated wafer processing apparatus according to claim 3, wherein the first holding mechanism and the second holding mechanism are the same holding mechanism.

5. A method for manufacturing a periphery-processed laminated wafer, in which a periphery-processed laminated wafer is manufactured by processing an outer periphery of a first wafer among laminated wafers formed by bonding one side of a first wafer and a second wafer each having a plate shape, a bonding misalignment acquisition step of acquiring a value related to bonding misalignment between the first wafer and the second wafer by measuring the position of an outer periphery of the first wafer and the position of an outer periphery of the second wafer; a holding step of holding the second wafer side of the stacked wafers on a holding surface of a holding mechanism; a first position acquiring step of acquiring a position of the first wafer relative to the holding mechanism while the stacked wafers are held by the holding mechanism after the holding step; a second position acquiring step of acquiring a position of the second wafer relative to the holding mechanism based on the value related to the bonding deviation acquired in the bonding deviation measuring step and the position of the first wafer acquired in the first position acquiring step; a processing step of processing an outer periphery of the first wafer using the position of the second wafer acquired in the second position acquisition step as a reference; A method for manufacturing a periphery-processed laminated wafer comprising the steps of:

6. A method for manufacturing a chip using the method for manufacturing a periphery-processed laminated wafer according to claim 1 or 5, After the processing step, the method further includes a dividing step of dividing the first wafer to obtain chips. How chips are manufactured.

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