Wafer processing method and cutting apparatus

Abstract

The present application provides a wafer processing method and a cutting device, even if the wafer is cut along the outer periphery, it can be positioned in the next process in a specified direction. The wafer processing method comprises the following steps: holding table preparation step, prepare the holding table formed with the recess corresponding to the wafer clearance; holding step, the recess of the wafer is corresponded with the clearance of the holding table, and the wafer is held by the holding table; small diameter step, in the state that the front end of the cutting tool is positioned below the holding surface of the holding table, the wafer is cut along the outer periphery of the wafer by the cutting tool to make the wafer small in diameter, so that at least part of the cutting part is removed; and cutting part forming step, the wafer is cut in the thickness direction along the clearance of the holding table by the cutting tool, and the second recess is formed on the wafer.

Description

TECHNICAL FIELD

[0001] The present application relates to a wafer processing method and a cutting device that reduces the diameter of a wafer that is circular and has a portion of a circular arc cut out by cutting the wafer along the outer periphery with a cutting tool. BACKGROUND

[0002] A wafer processing method that removes the entire circumference of the outer periphery of a wafer from the front surface on which devices are formed to the back surface is used (see, for example, Patent Literature 1).

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2013-102080

[0004] However, when the entire circumference of the outer periphery of a wafer is removed from the front surface on which devices are formed to the back surface by cutting, there is a problem in that a notch or orientation flat that indicates the crystal orientation disappears, the crystal orientation of the wafer cannot be detected in a subsequent process, and thus the wafer cannot be positioned in a prescribed orientation. SUMMARY

[0005] Accordingly, an object of the present application is to provide a wafer processing method and a cutting device that can position a wafer in a prescribed orientation in a next process even if the wafer is cut along the outer periphery.

[0006] According to one embodiment of the present application, a wafer processing method that reduces the diameter of a wafer that is circular and has a first cutout portion that indicates the crystal orientation, the first cutout portion being a portion of a circular arc cut out, by cutting the wafer along the outer periphery with a cutting tool, includes: a holding stage preparation step of preparing a holding stage that has a circular holding surface that holds the wafer and is formed with a relief portion that corresponds to the first cutout portion of the wafer held; a holding step of holding the wafer with the holding stage after the holding stage preparation step so that the first cutout portion of the wafer corresponds to the relief portion of the holding stage, the diameter of the holding surface of the holding stage corresponding to the diameter of the wafer after the diameter is reduced; a diameter reduction step of reducing the diameter of the wafer with the cutting tool after the holding step is performed so that at least a portion of the first cutout portion is removed by cutting the wafer along the outer periphery of the wafer with the cutting tool while the tip of the cutting tool is positioned at a position below the holding surface of the holding stage; and a cutout portion formation step of forming a second cutout portion on the wafer in the thickness direction by cutting the wafer along the relief portion of the holding stage with the cutting tool.

[0007] According to another aspect of the invention, a cutting apparatus is provided that reduces the diameter of a wafer by cutting it along its outer periphery with a cutting tool. The first cut portion is obtained by removing a portion of an arc. The cutting apparatus comprises: a holding stage having a circular holding surface for holding the wafer and forming a retraction portion corresponding to the cut portion of the held wafer; the holding stage having a diameter corresponding to the diameter of the reduced-diameter wafer; a rotation mechanism for rotating the holding stage about a rotation axis passing through the center of the holding surface; a cutting unit having a cutting tool for cutting the wafer held by the holding stage and a spindle with the cutting tool mounted at its front end; and a moving mechanism for moving the cutting unit relative to the holding stage.

[0008] The present invention has the following effect: even wafers that have been cut along their outer periphery can be positioned in a specified orientation in the next process. Attached Figure Description

[0009] Figure 1 This is a perspective view showing a structural example of the cutting device according to the first embodiment.

[0010] Figure 2 Through Figure 1 A three-dimensional view of a wafer being cut by the cutting device shown.

[0011] Figure 3 yes Figure 1 The top view of the holding table of the cutting device shown.

[0012] Figure 4 This is a flowchart illustrating the wafer fabrication method of the first embodiment.

[0013] Figure 5 It is shown Figure 4 The top view of the holding table in the holding step of the wafer processing method shown.

[0014] Figure 6 It is along Figure 5 A sectional view along line VI-VI.

[0015] Figure 7 It is shown Figure 4 A cross-sectional view of the miniaturization step in the wafer fabrication method shown.

[0016] Figure 8 It is shown Figure 4 The top view of the wafer fabrication method shown is a step in the process of forming the cut-off portion.

[0017] Figure 9 It is along Figure 8a cross-sectional view of the IX-IX line in FIG. 8.

[0018] Figure 10 is a perspective view of a wafer cut by the wafer processing method and cutting apparatus of the second embodiment.

[0019] Figure 11 is a plan view of a holding stage of the cutting apparatus of the second embodiment.

[0020] Figure 12 is a plan view showing a cutout portion forming step of the wafer processing method of the second embodiment.

[0021] Explanation of Reference Numerals

[0022] 1: cutting apparatus; 10: holding stage; 14: holding surface; 15, 15-2: retreat portion; 20, 20-1, 20-2: cutting unit (cutting member); 21, 21-1, 21-2: cutting tool; 22: spindle; 40: rotation moving unit (rotation mechanism); 41: moving unit (moving mechanism); 200: wafer; 201: outer peripheral edge; 206: recess (cutout portion); 206-2: orientation plane (cutout portion); 207: second recess (cutout portion); 207-2: second orientation plane (cutout portion); ST1: holding stage preparation step; ST2: holding step; ST3: small-diameterizing step; ST4: cutout portion forming step. DETAILED DESCRIPTION

[0023] Embodiments of the present application will be described below in detail with reference to the accompanying drawings. The present application is not limited by the contents described in the following embodiments. In addition, the following described constituent elements include what can be easily conceived by those skilled in the art, and substantially the same contents. In addition, the following described structures can be appropriately combined. In addition, various omissions, substitutions, or changes of the structures can be made within a range not departing from the gist of the present application.

[0024] [First Embodiment]

[0025] A cutting apparatus of the first embodiment of the present application will be described with reference to the drawings. Figure 1 is a perspective view showing a structure example of the cutting apparatus of the first embodiment. Figure 2 is a perspective view of a wafer cut by the cutting apparatus shown in Figure 1 Figure 3 is a plan view of a holding stage of the cutting apparatus shown in Figure 1

[0026] The cutting apparatus 1 of the first embodiment shown in Figure 1 Figure 2 ​​​An apparatus for reducing the outer periphery 201 of the wafer 200 to a smaller diameter by removing the entire circumference of the wafer 200 from the front surface 202 to the back surface 203. In the first embodiment, the wafer 200 is a wafer such as a semiconductor wafer or an optical device wafer that is circular and has a base material of silicon, sapphire, gallium, or the like. The wafer 200 is formed in a circular plate shape, and a device 205 is formed in a region on the front surface 202 that is divided in a grid pattern by a plurality of division predetermined lines 204 formed in a grid pattern. In addition, the wafer 200 has a notch 206 that is a cutout portion indicating the crystal orientation of the base material, obtained by cutting out a portion of a circular arc. The notch 206 is obtained by cutting out a portion of the base material from the outer periphery of the wafer 200 toward the center of the wafer 200.

[0027] Figure 1 The cutting apparatus 1 is also an apparatus for reducing the wafer 200 to a smaller diameter by cutting the wafer 200 along the outer periphery 201 with the cutting tool 21. As Figure 1 As shown, the cutting apparatus 1 has a holding stage 10 that holds the wafer 200 by suction on a holding surface 14, a cutting unit 20 that cuts the wafer 200 held by the holding stage 10, a photographing unit 30 that photographs the wafer 200 held by the holding stage 10 as a photographing member, and a control unit 100 that controls as a control member.

[0028] In addition, as Figure 1 As shown, the cutting apparatus 1 has a rotation moving unit 40 that rotates the holding stage 10 about a rotation axis parallel to the Z-axis direction along the vertical direction through the center of the holding surface 14 as a rotation mechanism, and a moving unit 41 that relatively moves the cutting unit 20 with respect to the holding stage 10 as a moving mechanism.

[0029] The moving unit 41 has an X-axis moving unit 42 that feeds the holding stage 10 in the X-axis direction parallel to the horizontal direction and the width direction of the apparatus main body 2, a Y-axis moving unit 43 that feeds the cutting unit 20 in the Y-axis direction parallel to the horizontal direction and the length direction of the apparatus main body 2 and perpendicular to the X-axis direction, and a Z-axis moving unit 44 that feeds the cutting unit 20 in the Z-axis direction parallel to the vertical direction perpendicular to both the X-axis direction and the Y-axis direction. The rotation moving unit 40 feeds the holding stage 10 in the X-axis direction together with the X-axis moving unit 42. As Figure 1 As shown, the cutting apparatus 1 is a cutting apparatus having two cutting units 20, that is, a dicing saw of two spindles, a so-called face-to-face dual-axis type cutting apparatus.

[0030] As Figure 3As shown, the holding stage 10 has: a circular frame 11 with a circular recess 13 in the center; and a holding member 12, which is installed in the recess 13 and is formed of a porous material such as porous ceramic. The holding stage 10 is formed in a disk shape. The frame 11 has a diameter corresponding to the diameter of the miniaturized wafer 200. Because the frame 11 has a diameter corresponding to the diameter of the miniaturized wafer 200, the holding stage 10 also has a diameter corresponding to the diameter of the miniaturized wafer 200.

[0031] In the first embodiment, the diameter of the frame 11 is slightly smaller than the diameter of the miniaturized wafer 200, that is, smaller than the diameter of the wafer 200 before miniaturization. The upper surface of the holding member 12 is formed in a circular shape and is formed on the same plane as the upper surface of the frame 11, serving as a holding surface 14 for holding the wafer 200. That is, the holding stage 10 includes a circular holding surface 14. The recess 13 of the holding stage 10 is connected to a vacuum suction source (not shown), and the wafer 200 placed on the holding surface 14 is attracted and held by the vacuum suction source.

[0032] Furthermore, the holding stage 10 has a retraction portion 15 formed on the outer edge of the frame 11, corresponding to the notch 206 of the held wafer 200. In the first embodiment, the retraction portion 15 is a recess extending from the outer edge of the frame 11 toward the center of the frame 11, and the width of the retraction portion 15 along the circumferential direction of the frame 11 is wider than the maximum width of the notch 206, and the retraction portion 15 is provided along the entire length of the frame 11 in the thickness direction. In addition, in the first embodiment, the retraction portion 15 is provided on both the frame 11 and the holding member 12.

[0033] Furthermore, the worktable 10 is configured to move freely along the X-axis direction via the X-axis moving unit 42 and rotate freely about the rotation axis via the rotation moving unit 40. Additionally, Figure 3 The wafer 200 before miniaturization is shown using dashed lines.

[0034] The cutting unit 20 cuts (equivalent to machining) the wafer 200 held by the holding stage 10. The cutting unit 20 is configured to be freely movable in the Y-axis direction via the Y-axis moving unit 43 and in the Z-axis direction via the Z-axis moving unit 44 relative to the wafer 200 held by the holding stage 10.

[0035] like Figure 1 As shown, a pair of cutting units 20 are mounted on a portal-shaped support frame 3 that is erected from the main body 2 of the device, by means of a Y-axis moving unit 43, a Z-axis moving unit 44, etc. The pair of cutting units 20 can position the cutting tool 21 at any position on the holding surface 14 of the holding table 10 by means of the Y-axis moving unit 43 and the Z-axis moving unit 44.

[0036] The pair of cutting units 20 has a spindle housing 23 provided so as to be movable in the Y-axis direction and the Z-axis direction by a Y-axis moving unit 43 and a Z-axis moving unit 44, a spindle 22 provided in the spindle housing 23 so as to be rotatable about the axis and rotated by a spindle motor, and a cutting tool 21 mounted at the front end, and cuts a wafer 200 held by the holding stage 10. The cutting tool 21 is an extremely thin cutting abrasive having a substantially ring shape. The axis of the spindle 22 of the cutting unit 20 and the cutting tool 21 is set to be parallel to the Y-axis direction.

[0037] The X-axis moving unit 42 moves the holding stage 10 in the X-axis direction which is the machining feed direction, thereby relatively machining feeding the holding stage 10 and the cutting unit 20 in the X-axis direction. The Y-axis moving unit 43 moves the cutting unit 20 in the Y-axis direction which is the indexing feed direction, thereby relatively indexing feeding the holding stage 10 and the cutting unit 20 in the Y-axis direction. The Z-axis moving unit 44 moves the cutting unit 20 in the Z-axis direction which is the plunge feed direction, thereby relatively plunge feeding the holding stage 10 and the cutting unit 20 in the Z-axis direction.

[0038] The X-axis moving unit 42, the Y-axis moving unit 43, and the Z-axis moving unit 44 have a known ball screw provided so as to be rotatable about the axis, a known pulse motor which rotates the ball screw about the axis, and a known guide rail which supports the holding stage 10 or the cutting unit 20 so as to be movable in the X-axis direction, the Y-axis direction, or the Z-axis direction.

[0039] In addition, the cutting apparatus 1 has an X-axis direction position detecting unit (not shown) for detecting the position of the holding stage 10 in the X-axis direction, a Y-axis direction position detecting unit (not shown) for detecting the position of the cutting unit 20 in the Y-axis direction, and a Z-axis direction position detecting unit for detecting the position of the cutting unit 20 in the Z-axis direction. The X-axis direction position detecting unit and the Y-axis direction position detecting unit can be constituted by a linear scale and a reading head parallel to the X-axis direction or the Y-axis direction. The Z-axis direction position detecting unit detects the position of the cutting unit 20 in the Z-axis direction using the pulse of the pulse motor. The X-axis direction position detecting unit, the Y-axis direction position detecting unit, and the Z-axis direction position detecting unit output the position of the holding stage 10 in the X-axis direction, the position of the cutting unit 20 in the Y-axis direction, or the position of the cutting unit 20 in the Z-axis direction to the control unit 100. In addition, in the first embodiment, each position is determined by the distance from a reference position set in advance in the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0040] Further, the cutting apparatus 1 has a cassette elevator 50 that places a cassette 51 that houses the wafer 200 before and after cutting and moves the cassette 51 in the Z-axis direction, a cleaning unit 60 that cleans the wafer 200 after cutting, and a conveyance unit 70 that brings the wafer 200 in and out with respect to the cassette 51 and conveys the wafer 200. In the first embodiment, the conveyance unit 70 has a pair of conveyance arms 71 that convey the wafer 200.

[0041] The photographing unit 30 photographs the wafer 200 held by the holding surface 14 of the holding table 10. In the first embodiment, the photographing unit 30 is fixed to the cutting unit 20 in a manner that moves integrally with the cutting unit 20. The photographing unit 30 has a photographing element that photographs the region to be divided of the wafer 200 before cutting held by the holding table 10. The photographing element is, for example, a CCD (Charge-Coupled Device) photographing element or a CMOS (Complementary MOS) photographing element. The photographing unit 30 photographs the wafer 200 held by the holding table 10 and obtains an image for performing alignment, that is, performing positioning of the wafer 200 with the cutting tool 21, and the like, and outputs the obtained image to the control unit 100.

[0042] Further, the cutting apparatus 1 has a second photographing unit 80 that photographs the wafer 200 taken out from the cassette 51. The second photographing unit 80 has a photographing element that photographs a region including the notch 206 of the wafer 200 before cutting held by the holding table 10. The photographing element is, for example, a CCD (Charge-Coupled Device) photographing element or a CMOS (Complementary MOS) photographing element. The second photographing unit 80 photographs the wafer 200 taken out from the cassette 51 and obtains an image for detecting the position of the notch 206 and the like, and outputs the obtained image to the control unit 100.

[0043] The control unit 100 controls each of the above-described units of the cutting apparatus 1 to cause the cutting apparatus 1 to perform a processing operation on the wafer 200. In addition, the control unit 100 is a computer that includes an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing in accordance with a computer program stored in the storage device, and outputs a control signal for controlling the cutting apparatus 1 to the above-described components of the cutting apparatus 1 via the input / output interface device.

[0044] In addition, the control unit 100 is connected to a not-illustrated display unit configured by a liquid crystal display device or the like that displays a state or an image of a processing operation and the like, and an input unit used by an operator when registering processing content information or the like. The input unit is configured by at least one of an external input device such as a touch panel and a keyboard provided to the display unit.

[0045] (Method of processing a wafer)

[0046] A method of processing a wafer according to a first embodiment of the present application will be described with reference to the drawings. Figure 4 is a flowchart showing a flow of the method of processing a wafer according to the first embodiment. The method of processing a wafer according to the first embodiment is a method of reducing the diameter of a wafer 200 by cutting the wafer 200 along an outer periphery 201 using a cutting tool 21. As shown in Figure 4 The method of processing a wafer has a holding stage preparation step ST1, a holding step ST2, a diameter reduction step ST3, and a cutout portion formation step ST4.

[0047] (Holding stage preparation step)

[0048] The holding stage preparation step ST1 is a step of preparing the above-described holding stage 10. In the holding stage preparation step ST1, the above-described holding stage 10 is prepared, and the holding stage 10 is installed to the rotary moving unit 40. In addition, in the first embodiment, in the holding stage preparation step ST1, an operator registers processing content information in the control unit 100, places a cassette 51 in which the wafer 200 is accommodated to the cassette elevator 50, and proceeds to the holding step ST2.

[0049] (Holding step)

[0050] Figure 5 is a flowchart showing a flow of the method of processing a wafer according to the first embodiment. The method of processing a wafer according to the first embodiment is a method of reducing the diameter of a wafer 200 by cutting the wafer 200 along an outer periphery 201 using a cutting tool 21. As shown in Figure 4The figure shows a top view of the holding stage in the wafer processing method. Figure 6 is a top view of the holding stage in the holding step. Figure 5 The cross-sectional view along line VI-VI. The holding step ST2 is a step in which the notch 206 of the wafer 200 is aligned with the retraction part 15 of the holding stage 10 after the holding stage preparation step ST1, and the wafer 200 is held by the holding stage 10.

[0051] In the first embodiment, during the holding step ST2, when the cutting device 1 receives a start instruction for processing from the operator, it controls the conveying unit 70 to remove a wafer 200 from the cassette 51. In the first embodiment, during the holding step ST2, the cutting device 1 detects the notch 206 based on an image captured by the second imaging unit 80, and controls one of the conveying unit 70 and the rotary movement unit 40, as shown in FIG5. Figure 6 As shown, the back surface 203 side of the wafer 200 is placed on the holding surface 14 such that the wafer 200 and the holding surface 14 are coaxial and the retraction portion 15 and the notch 206 are arranged side by side in the radial direction. In the holding step ST2, the cutting device 1 attracts and holds the back surface 203 side on the holding surface 14 of the holding table 10, proceeding to the miniaturization step ST3. Furthermore, Figure 5 The pre-defined dividing line 204 and the device 205 are omitted.

[0052] (Minimum diameter reduction step)

[0053] Figure 7 It is shown Figure 4 The diagram shows a cross-sectional view of the miniaturization step in the wafer processing method. Miniaturization step ST3 is as follows: after holding step ST2, with the tip of the cutting tool 21 positioned below the holding surface 14 of the holding table 10, the cutting tool 21 is used to cut along the outer periphery 201 of the wafer 200 to reduce the diameter of the wafer 200, thereby removing at least a portion of the notch 206.

[0054] In the miniaturization step ST3, the cutting device 1 controls the moving unit 41 to position the lower end of the cutting edge of the rotating cutting tool 21 (hereinafter referred to as 21-1) of one of the cutting units 20 (hereinafter referred to as 20-1) below the holding surface 14 of the holding table 10. In the miniaturization step ST3, the cutting device 1 controls the moving unit 41 to position the lower end of the cutting edge of the cutting tool 21-1 of one of the cutting units 20-1 side-by-side with the outer periphery 201 of the wafer 200 protruding from the outer edge of the holding table 10 in the X-axis direction. Then, the holding table 10 is moved along the X-axis in a direction closer to one of the cutting units 20-1.Figure 7 The cutting edge of the cutting tool 21-1 is made to cut into the outer periphery 201 of the wafer 200.

[0055] In the reduction step ST3, the cutting device 1 rotates the holding stage 10 around the rotation axis after making the cutting edge of the cutting tool 21-1 cut into the outer periphery 201 of the wafer 200, and relatively moves the cutting tool 21-1 along the outer periphery 201 with respect to the wafer 200. In the reduction step ST3, the cutting device 1 removes the outer periphery 201 along the entire circumference to reduce the wafer 200, and proceeds to the cutout portion forming step ST4. In the first embodiment, the cutting device 1 removes the notches 206 entirely in the reduction step ST3, but in the present application, a part of the notches 206 can be left on the wafer 200. In addition, the thickness of the cutting edge of the cutting tool 21-1 that removes the outer periphery 201 of the wafer 200 in the reduction step ST3 is equal to the width of the outer periphery 201 removed from the wafer 200.

[0056] (Cutout portion forming step)

[0057] Figure 8 is a plan view showing Figure 4 is a plan view showing the cutout portion forming step of the wafer processing method. Figure 9 is a sectional view along the IX-IX line in Figure 8 The cutout portion forming step ST4 is a step of forming the second notch 207 as a cutout portion on the wafer 200 by cutting the wafer 200 in the thickness direction with the cutting tool 21 along the relief portion 15 of the holding stage 10.

[0058] In the cutout portion forming step ST4, the cutting device 1 controls the rotation moving unit 40 to position the relief portion 15 at the end portion of the holding stage 10 in the X-axis direction, and controls the moving unit 41 to make the cutting edge of the cutting tool 21 (hereinafter, referred to as reference numeral 21-2) of the other cutting unit 20 (hereinafter, referred to as reference numeral 20-2) in rotation oppose the relief portion 15 in the X-axis direction. In addition, in the cutout portion forming step ST4, the cutting device 1 controls the moving unit 41 to position the lower end as the tip end of the cutting tool 21-2 below the holding surface 14 of the holding stage 10. In the cutout portion forming step ST4, the cutting device 1 controls the moving unit 41 to move the holding stage 10 in the X-axis direction in the direction of approaching the other cutting unit 20-2, and thereby makes the cutting edge of the cutting tool 21-2 cut into the outer periphery of the wafer 200 as shown in Figure 8 and Figure 9 The cutting edge of the cutting tool 21-2 is made to cut into the outer periphery of the wafer 200, and the cutting tool 21-2 is made to enter into the relief portion 15.

[0059] In the cut portion forming step ST4, the cutting device 1 forms the second notch 207 by cutting the cutting edge of the cutting tool 21-2 into the outer edge of the wafer 200, and then controls the moving unit 41 to move the holding stage 10 away from the cutting unit 20-2. The second notch 207, like the notch 206, is a cut portion indicating the crystal orientation of the base material, and indicates the same crystal orientation as the notch 206. The second notch 207 is a groove obtained by cutting a portion of the base material from the outer edge of the wafer 200 toward the center of the wafer 200.

[0060] In the cut portion forming step ST4, the cutting device 1 stops the suction holding of the holding stage 10, and controls the conveyance unit 70 to convey the wafer 200 to the cleaning unit 60. In the cut portion forming step ST4, the cutting device 1 controls the cleaning unit 60 to clean the wafer 200, and controls the conveyance unit 70 to convey the wafer 200 into the cassette 51, and ends the wafer processing method. In addition, in the cut portion forming step ST4, the cutting edge of the cutting tool 21-2 that is cut into the outer edge of the wafer 200 is thinner than the cutting edge of the cutting tool 21-1 of the cutting unit 20 on one side. In addition, Figure 8 The division intended line 204 and the device 205 are omitted.

[0061] The wafer processing method and the cutting device 1 of the above-described first embodiment prepare the holding stage 10 in which the relief portion 15 is formed corresponding to the notch 206 of the wafer 200. The wafer processing method and the cutting device 1 align the notch 206 of the wafer 200 and the relief portion 15 in the radial direction, and hold the wafer 200 so that the notch 206 corresponds to the relief portion 15 of the holding stage 10. The wafer processing method and the cutting device 1 perform cutting along the outer edge 201 while holding the wafer 200 by the holding stage 10, and perform cutting along the relief portion 15. Therefore, the wafer processing method and the cutting device 1 form a new second notch 207 that indicates the same crystal orientation as the notch 206 of the wafer 200 before the reduction in diameter, on the wafer 200 after the reduction in diameter, and thus can detect the crystal orientation of the wafer 200 after the reduction in diameter, and can be positioned in a predetermined orientation in the next process. As a result, the wafer processing method and the cutting device 1 have the effect that even the wafer 200 on which cutting has been performed along the outer edge 201 can be positioned in a predetermined orientation in the next process.

[0062] [Second Embodiment]

[0063] A wafer processing method and a cutting device according to a second embodiment of the present application will be described with reference to the drawings. Figure 10 is a perspective view of a wafer that is cut by the wafer processing method and the cutting device according to the second embodiment. Figure 11is a plan view of the holding stage of the cutting apparatus of the second embodiment. Figure 12 is a plan view of the cutting step of the wafer processing method of the second embodiment. Figure 10 、 Figure 11 and Figure 12 In the second embodiment, the same reference numerals are assigned to the same parts as those of the first embodiment, and the description thereof is omitted.

[0064] As shown in Figure 10 , the wafer 200-2 subjected to cutting by the wafer processing method of the second embodiment and the cutting apparatus 1 has a directional plane 206-2 as a cutout portion indicating the crystal orientation of the base material instead of the notch 206. A part of the circular arc of the wafer 200-2 is cut out to form the directional plane 206-2 in a linear shape.

[0065] As shown in Figure 11 , the holding stage 10-2 of the cutting apparatus 1 of the second embodiment is formed with a relief portion 15-2 corresponding to the directional plane 206-2 of the held wafer 200-2 at the outer edge of the frame 11. In the second embodiment, the relief portion 15-2 is formed in a linear shape at the outer edge of the frame 11 and is disposed along the entire length in the thickness direction of the frame 11. In addition, in the second embodiment, the relief portion 15-2 is disposed on both the frame 11 and the holding member 12. In addition, Figure 11 The wafer 200-2 before being reduced in diameter is indicated by a dotted line.

[0066] The holding stage preparation step ST1 of the wafer processing method of the second embodiment is implemented in the same manner as in the first embodiment. In the holding step ST2 of the wafer processing method of the second embodiment, the cutting apparatus 1 detects the directional plane 206-2 based on the image captured by the second imaging unit 80, controls one of the conveyance unit 70 and the rotation movement unit 40, and places the back surface 203 side of the wafer 200-2 on the holding surface 14 in such a manner that the wafer 200-2 is coaxial with the holding surface 14 and the relief portion 15-2 is parallel to the directional plane 206-2, as shown in Figure 11 . The back surface 203 side of the wafer 200-2 is attracted and held on the holding surface 14 of the holding stage 10-2.

[0067] The miniaturization step ST3 of the wafer processing method of the second embodiment is implemented similarly to the first embodiment, and in the cutout portion forming step ST4 of the wafer processing method of the second embodiment, the cutting device 1 controls the rotational movement unit 40 to position the relief portion 15-2 and the orientation flat 206-2 in parallel with the X-axis direction, and controls the movement unit 41 to position the cutting edge of the cutting tool 21-2 in the rotation of the other cutting unit 20-2 in opposition to the portion of the wafer 200-2 protruding from the relief portion 15-2 in the X-axis direction.

[0068] In addition, in the cutout portion forming step ST4 of the wafer processing method of the second embodiment, the cutting device 1 controls the movement unit 41 to position the lower end of the tip of the cutting tool 21-2 below the holding surface 14 of the holding table 10. In the cutout portion forming step ST4 of the wafer processing method of the second embodiment, the cutting device 1 controls the movement unit 41 to move the holding table 10-2 in the direction of approaching the other cutting unit 20-2 along the X-axis direction, cuts the cutting edge of the cutting tool 21-2 into the outer edge of the wafer 200-2, and moves the cutting tool 21-2 relatively to the holding table 10-2 along the relief portion 15, as shown in FIG. 8. Figure 12

[0069] In the cutout portion forming step ST4, the cutting device 1 cuts the cutting tool 21-2 into the outer edge of the wafer 200-2 to perform cutting to form the second orientation flat 207-2 as a cutout portion, and then controls the movement unit 41 to move the holding table 10-2 away from the cutting unit 20-2, and similarly to the first embodiment, ends the wafer processing method. The second orientation flat 207-2 is similarly to the orientation flat 206-2 a cutout portion indicating the crystal orientation of the base material, and indicates the same crystal orientation as the orientation flat 206-2. The second orientation flat 207-2 is formed in a straight line by cutting a portion of the circular arc of the wafer 200-2.

[0070] ​The wafer processing method and the cutting apparatus 1 prepare the holding table 10-2 formed with the relief portion 15-2 corresponding to the orientation flat surface 206-2 of the wafer 200-2, and hold the wafer 200-2 with the orientation flat surface 206-2 and the relief portion 15-2 positioned in parallel. The wafer processing method and the cutting apparatus 1 cut along the outer periphery 201 while holding the wafer 200-2 with the holding table 10-2, and cut along the relief portion 15-2. Thus, the wafer processing method and the cutting apparatus 1 form the new second orientation flat surface 207-2 having the same crystal orientation as the orientation flat surface 206-2 of the wafer 200-2 before the reduction in diameter on the wafer 200-2 after the reduction in diameter, and can detect the crystal orientation of the wafer 200-2 after the reduction in diameter and position in a predetermined orientation in the next process. As a result, the wafer processing method and the cutting apparatus 1 have the effect that the wafer 200-2 cut along the outer periphery 201 can be positioned in a predetermined orientation in the next process.

[0071] In addition, the present application is not limited to the above-described embodiments. That is, various modifications can be made and implemented within the scope of the gist of the present application. For example, the wafer processing method of the present application can implement the cutout portion forming step ST4 before the reduction in diameter step ST3. In addition, the present application can position the wafer 200, 200-2 on the holding surface 14 of the holding table 10 in the holding step ST2 by the operator in a manual operation manner as in the first embodiment and the second embodiment.

Claims

1. A wafer processing method of reducing in diameter a wafer that is circular and has a first cutout portion indicating a crystal orientation, the first cutout portion being obtained by cutting a part of a circular arc, wherein the wafer processing method has the following steps: a holding stage preparation step of preparing a holding stage that has a circular holding surface on which a wafer is held and that is formed with a relief portion corresponding to the first cutout portion of the held wafer, and that has a diameter smaller than a diameter of the wafer before the reduction in diameter; a holding step of, after the holding stage preparation step, causing the first cutout portion of the wafer to correspond to the relief portion of the holding stage, and positioning an outer periphery of the wafer at a position on an outer periphery side than an outer periphery of the holding stage in an entire circumferential range and holding the wafer by the holding stage, a diameter of the holding surface of the holding stage corresponding to a diameter of the wafer after the reduction in diameter; a reduction in diameter step of, after the holding step, moving the holding stage in a horizontal direction toward a direction in which the holding stage approaches a cutting tool in a state in which a tip of the cutting tool is positioned at a position below the holding surface of the holding stage, causing the cutting tool to cut into the outer periphery of the wafer, rotating the holding stage around a rotation axis parallel to a vertical direction, and reducing in diameter the wafer by cutting the wafer along the outer periphery of the wafer by the cutting tool, thereby removing at least a part of the first cutout portion; and a cutout portion formation step of cutting the wafer in a thickness direction along the relief portion of the holding stage by the cutting tool, and forming a second cutout portion on the wafer.

2. A cutting apparatus that reduces in diameter a wafer that is circular and has a cutout portion indicating a crystal orientation, the cutout portion being obtained by cutting a part of a circular arc, wherein the cutting apparatus has: a holding stage that has a circular holding surface on which a wafer is held and that is formed with a relief portion corresponding to the cutout portion of the held wafer, and that has a diameter smaller than a diameter of the wafer before the reduction in diameter; a rotation mechanism that rotates the holding stage around a rotation axis passing through a center of the holding surface; a cutting unit that has a cutting tool that cuts the wafer held by the holding stage, and a spindle on which the cutting tool is installed at a tip; and a moving mechanism that relatively moves the cutting unit with respect to the holding stage, wherein an outer periphery of the wafer is positioned at a position on an outer periphery side than an outer periphery of the holding stage in an entire circumferential range and the wafer is held by the holding stage, the holding stage is moved in a horizontal direction toward a direction in which the holding stage approaches the cutting tool in a state in which a tip of the cutting tool is positioned at a position below the holding surface of the holding stage, the holding stage is rotated around the rotation axis, and the wafer is reduced in diameter by cutting the wafer along the outer periphery of the wafer by the cutting tool. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The wafer is cut in the thickness direction along the retreat portion of the holding table by the cutting tool, and a cutout portion is formed on the wafer.

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