Processing device and wafer processing method

Abstract

The present invention provides a processing device and a method for processing a wafer. The following technology is proposed: for a wafer having a circular concave portion and a peripheral convex portion formed on the back surface, the wafer can be singulated without removing the wafer from the holding table. The processing device processes the wafer, wherein the processing device includes: a rotatable holding table having a holding portion made of a transparent material for holding the front side of the wafer; a bottom-shooting camera for photographing the front side of the wafer held by the holding table through the holding portion; a first cutting unit having a first cutting tool for cutting the peripheral convex portion on the back surface of the wafer to reduce the height of the peripheral convex portion; and a second cutting unit having a second cutting tool for cutting the wafer along a spacing path on the front side of the wafer photographed by the bottom-shooting camera.

Description

Technical Field

[0001] The present invention relates to a processing device for processing a wafer having an outer peripheral convex portion formed by a circular concave portion on the back surface, and a processing method using the processing device. Background Art

[0002] In the process of processing a semiconductor wafer, there is a concern that the wafer may be damaged due to insufficient strength in the process of forming a metal film on the back surface of a thinned wafer.

[0003] To prevent such wafer breakage, a known technique is to leave the original thickness of the wafer without grinding the remaining peripheral area during wafer back grinding, thereby forming a peripheral convex portion, which serves as a reinforcement portion.

[0004] Furthermore, when the metal film is formed and then divided into individual chips, it is necessary to cut with the front side of the chip facing upwards. Therefore, a holding table corresponding to the shape of a circular recess surrounded by a peripheral convex portion is used. For example, Patent Document 1 discloses a so-called convex holding table having a disc-shaped porous adsorption portion that engages with the circular recess.

[0005] On the other hand, Patent Document 2 discloses a technology in which a circular recess is formed by grinding an area corresponding to a device area on the back side of a chip, thereby forming a peripheral convex portion; after additional processing is performed on the device area or the back side of the chip after back grinding, the peripheral convex portion of the chip after the additional processing is removed.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-016146

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-019379

[0008] However, the width of the peripheral protrusions serving as reinforcements varies depending on the wafer pattern (chip size or device area size). Therefore, in the structure based on a protruding holding table, as disclosed in Patent Document 1, it is necessary to manufacture a holding table corresponding to the different widths of the peripheral protrusions for each wafer, which also creates a management burden and is complicated. Furthermore, the time required to replace the protrusions during processing reduces the operating time of the device.

[0009] As a method that does not use a convex holding workbench, it is considered to cut the chip with the back side of the chip exposed upward. However, when a metal film is formed on the back side of the chip, the front side cannot be photographed using an IR camera, so there is a problem that the spacing channel cannot be detected and alignment cannot be performed.

[0010] Based on the above, it is also considered not to form a film on the upper end of the peripheral protrusion, and use an IR camera to photograph the area to detect the spacing path. However, the pattern accuracy of the peripheral part is low, making it difficult to perform high-precision alignment and thus difficult to adopt this method.

[0011] On the other hand, it is conceivable to remove the outer peripheral protrusions to make the back surface of the wafer flat, and then cut the wafer with the front surface facing upward, as in Patent Document 2. This eliminates the need for a convex holding table.

[0012] In this case, the front side of the chip is exposed for processing, so it is necessary to stick the tape on the back side of the chip. However, the peripheral protrusion of the thinned chip, which serves as a reinforcing part, is removed, thereby weakening the strength of the chip. Therefore, there is a concern that the chip may be damaged during the tape sticking operation. Summary of the Invention

[0013] Therefore, an object of the present invention is to provide a processing apparatus and a wafer processing method that can separate a wafer having circular concave portions and peripheral convex portions formed on its back surface without removing the wafer from a holding table.

[0014] According to one embodiment of the present invention, a processing device is provided for processing a chip, wherein the chip has a recess formed on the back side corresponding to a device area on the front side, and a peripheral convex portion surrounding the recess is formed on the back side, wherein devices are respectively formed in each area divided by a plurality of intersecting spacing lanes in the device area, wherein the processing device comprises: a rotatable holding table having a holding portion made of a transparent material for holding the front side of the chip; a lower shooting camera for shooting the front side of the chip held by the holding table through the holding portion; a cutting mechanism having a first cutting unit and a second cutting unit, the first cutting unit having a first cutting tool for cutting the peripheral convex portion on the back side of the chip to reduce the height of the peripheral convex portion, the second cutting unit having a second cutting tool for cutting the chip along the spacing lane on the front side of the chip shot by the lower shooting camera; and a moving mechanism for moving the holding table and the cutting mechanism relative to each other.

[0015] Preferably, the processing apparatus further includes an upper imaging camera for imaging the back surface of the wafer held by the holding table.

[0016] According to another aspect of the present invention, a method for processing a wafer is provided, wherein the method for processing the wafer has the following steps: a wafer preparation step of preparing a wafer, wherein the wafer has a recess formed on the back side corresponding to the device area on the front side, and a peripheral convex portion surrounding the recess is formed on the back side, wherein in the device area, devices are respectively formed in each area divided by a plurality of intersecting spacing lanes; a protective component disposing step of arranging a transparent protective component on the front side of the wafer; and a holding step of protecting the front side of the wafer through the protective component using a holding workbench having a holding portion made of a transparent material. holding; a first cutting step, for the peripheral convex portion of the chip held by the holding workbench, cutting is performed by making the front end of the first cutting tool cut into the height that does not reach the bottom surface of the recessed portion, so that the height of the peripheral convex portion is reduced; a spacing lane detection step, after implementing the first cutting step, using a lower shooting camera arranged below the holding workbench to shoot the front side of the chip through the transparent holding portion and the transparent protective component to detect the spacing lane; and a second cutting step, using a second cutting tool to cut the chip along the spacing lane detected in the spacing lane detection step.

[0017] According to the structure of the present invention, in a chip with a circular recess and a peripheral protrusion formed on the back side, the chip can be singulated without removing the chip from the holding workbench, and the possibility of chip breakage caused when the chip is removed from the holding workbench and operated can be prevented.

[0018] Furthermore, since the first cutting tool processes the outer convex portion, the thickness of the outer convex portion is reduced, eliminating the need to set the second cutting tool's blade tip protrusion excessively, and cutting can be performed with an appropriate blade tip protrusion. This can prevent problems such as chipping and vibration of the cutting tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic perspective view of a processing device according to an embodiment of the present invention.

[0020] Figure 2 This is an exploded perspective view of the support box and the holding table.

[0021] Figure 3 (A) is a perspective view of the holding table mounted on the support box. Figure 3 (B) is a stereoscopic view of the bottom-shooting camera and its supporting structure.

[0022] Figure 4 This figure explains the positional relationship between the holding table and the camera shooting below.

[0023] Figure 5(A) is a perspective view of a wafer as an example of a workpiece. Figure 5 (B) is a perspective view of the back side of the wafer.

[0024] Figure 6 (A) is a diagram illustrating the attachment of the protective component. Figure 6 (B) is a perspective view of the chip unit.

[0025] Figure 7 (A) is a partial cross-sectional side view showing a first cutting step of removing the peripheral convex portion using a first cutting tool, Figure 7 (B) is a cross-sectional view of the wafer after the outer peripheral protrusions are removed.

[0026] Figure 8 (A) is a partial cross-sectional side view illustrating a situation in which the front surface of the wafer is photographed through a holding pad. Figure 8 (B) is a partial cross-sectional side view illustrating cutting processing by the second cutting unit.

[0027] Label Description

[0028] 2: Processing device; 10: Wafer; 10a: Front side; 10b: Back side; 11: Device; 13: Spacer; 18: Recess; 18a: Metal film; 19: Peripheral protrusion; 23: Moving mechanism; 27: Holding table; 46: First cutting unit; 46a: Second cutting unit; 50: First cutting tool; 50a: Second cutting tool; 52: Upper camera; 74: Holding pad; 74a: Holding portion; 82: Lower camera; T: Belt. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a perspective view of a machining device 2 according to one embodiment of the present invention. The machining device 2 is configured as a facing dual-spindle type cutting device in which two cutting tools are disposed so as to face each other.

[0030] On the base 4 of the processing device 2, a moving mechanism 23 ( Figure 3 (A)) A holding table 27 is provided so as to reciprocate in the X-axis direction. A waterproof cover 14 is provided around the holding table 27, and an accordion portion 16 is connected to the waterproof cover 14 and the base 4.

[0031] A cassette placement table 21 for placing a cassette 20 for storing a workpiece, which will be described later, is provided at a front corner of the base 4 .

[0032] A gate-shaped column 24 is erected on the base 4, and a pair of guide rails 26 extending in the Y-axis direction are fixed to the column 24. A first Y-axis moving block 28 is mounted on the column 24. The first Y-axis moving block 28 is guided by the guide rails 26 via a first Y-axis moving mechanism 34 composed of a ball screw 30 and a pulse motor (not shown) and is movable in the Y-axis direction.

[0033] A pair of guide rails 36 extending in the Z-axis direction are fixed to the first Y-axis moving block 28. A first Z-axis moving block 38 is mounted on the first Y-axis moving block 28. The first Z-axis moving block 38 is guided by the guide rails 36 via a first Z-axis moving mechanism 44 composed of a ball screw 40 and a pulse motor 42, and is movable in the Z-axis direction.

[0034] The first cutting unit 46 and the upper shooting camera 52 are mounted on the first Z-axis moving block 38. Figure 7 As shown in FIG. 1A , the first cutting unit 46 includes a first cutting blade 50 detachably mounted on a front end portion of a spindle 48 that is rotationally driven by a motor (not shown).

[0035] A second Y-axis moving block 28 a is mounted on the gate-shaped column 24 . The second Y-axis moving block 28 a is movable in the Y-axis direction by being guided by the guide rail 26 via a second Y-axis moving mechanism 34 a including a ball screw 30 a and a pulse motor 32 a .

[0036] A pair of guide rails 36a extending in the Z-axis direction are fixed to the second Y-axis moving block 28a. A second Z-axis moving block 38a is mounted on the second Y-axis moving block 28a. The second Z-axis moving block 38a is guided by the guide rails 36a and can move in the Z-axis direction via a second Z-axis moving mechanism 44a composed of a ball screw 40a and a pulse motor 42a.

[0037] A second cutting unit 46a is mounted on the second Z-axis moving block 38a. The second cutting unit 46a is configured by detachably mounting a second cutting tool on the front end of a spindle that is rotationally driven by a motor (not shown).

[0038] A spin cleaning unit 54 having a spin table 56 is provided on the base 4 . The spin table 56 sucks and holds the workpiece after cutting, performs spin cleaning, and further spin-dries the workpiece after cleaning.

[0039] Figure 2This figure illustrates the structure of the holding table 27. The holding table 27 includes an annular support member 62 and a disc-shaped holding pad 74. The annular support member 62 includes a fitting protrusion 64, a belt winding portion 66 having a larger diameter than the fitting protrusion 64, an annular housing portion 68 having approximately the same diameter as the fitting protrusion 64, a through portion 65 extending axially therethrough, and an inner peripheral surface 65a forming the through portion 65.

[0040] The annular housing portion 68 has an inner diameter substantially the same as the outer shape of the retaining pad 74 , and an annular support portion 70 for supporting the retaining pad 74 is formed on the inner bottom of the annular housing portion 68 .

[0041] The holding pad 74 is formed of a transparent material such as quartz glass, borosilicate glass, sapphire, calcium fluoride, lithium fluoride, or magnesium fluoride, and a plurality of fine holes 76 are opened on the holding portion 74a on the front side of the holding pad 74. In addition, the "transparency" of the transparent material means "transmitting light of at least a portion of the wavelength of visible light without absorption or scattering", and any material can be used as long as the peripheral convex portion detection step and the interval detection step described later can be performed. In addition, the arrangement of the fine holes 76 is not particularly limited. Figure 2 Instead of being arranged on the circumference as shown, for example, they may be arranged on the entire surface of the holding portion 74a.

[0042] Each of the fine holes 76 and the suction groove 78a ( Figure 4 ) is connected, and a suction groove 78a ( Figure 4 ) is connected to a communication path 72. The communication path 72 is connected to a suction source 80.

[0043] When the holding pad 74 is mounted on the annular support portion 70 of the annular support member 62 and the fitting protrusion 64 of the annular support member 62 is fitted into the circular opening 15a of the support box 15, as shown in FIG. Figure 3 As shown in FIG. 1 (A), the table 27 is held in a state where it is rotatably mounted on the support box 15 .

[0044] The motor 17 is mounted on the connecting plate 15b of the support box 15. The belt 29 is wound around the pulley 17a connected to the output shaft of the motor 17 and the belt winding portion 66 of the annular support member 62. When the motor 17 is driven, the holding table 27 is rotated via the belt 29.

[0045] The motor 17 is composed of a pulse motor, for example. When the motor 17 is driven according to a predetermined pulse during alignment, the worktable 27 is rotated (θ rotation) by a predetermined amount, and alignment can be performed. Figure 5 Alignment of the streets (scheduled dividing lines) 13 of the wafer 10 shown in (A).

[0046] A plurality of (four in this embodiment) frame support platforms 15 d are formed on the upper plate 15 c of the support box 15 , and a ring-shaped frame described later is supported by the upper surfaces of these frame support platforms 15 d .

[0047] like Figure 3 As shown in FIG. 1A , the support box 15 is slidably mounted on a pair of guide rails 31 fixedly extending in the X-axis direction and is moved in the X-axis direction by a moving mechanism 23 . The moving mechanism 23 includes a pulse motor 23 b and a ball screw 23 a arranged parallel to the guide rails 31 .

[0048] like Figure 3 As shown in FIG. 1A , the ball screw 23a is screwed into the external thread portion provided on the lower surface of the lower plate 15e of the support box 15. The pulse motor 23b is driven to rotate the ball screw 23a, thereby moving the support box 15 in the X-axis direction.

[0049] like Figure 3 As shown in FIG. 2A , a downward imaging camera 82 is provided near the support box 15 of the holding table 27 . The downward imaging camera 82 captures an image of a workpiece such as a semiconductor wafer held by the holding table 27 from below the holding pad 74 .

[0050] like Figure 3 As shown in FIG. 8A , the downward shooting camera 82 is mounted on a column 96 that is vertically mounted on a Y-axis moving block 83. The Y-axis moving block 83 is slidably mounted on a pair of guide rails 81 that extend fixedly in the Y-axis direction and is moved in the Y-axis direction by a drive unit 85. The drive unit 85 includes a pulse motor 85b and a ball screw 85a that is arranged parallel to the guide rails 81.

[0051] like Figure 3 As shown in FIG. 8A , the ball screw 85 a is screwed with the external thread portion provided on the lower surface of the Y-axis moving block 83 , and the pulse motor 85 b is driven to rotate the ball screw 85 a , thereby moving the Y-axis moving block 83 in the Y-axis direction.

[0052] like Figure 3 As shown in FIG. 8 (B), the downward shooting camera 82 includes a camera unit 84 having a low-magnification camera 86 and a high-magnification camera 88. Two lighting devices 90 and 92 for illuminating the shooting area when the camera unit 84 shoots are mounted on the side surface of the camera unit 84.

[0053] like Figure 3As shown in (B), the camera unit 84 is supported by a support plate 94, and the base end of the support plate 94 is fixed to a Z-axis moving block 98. On a column 96 erected on the Y-axis moving block 83, the camera unit 84 constituting the lower imaging camera 82 is moved in the Z-axis direction (vertical direction) along a pair of guide rails 106 by a Z-axis moving unit 104 composed of a ball screw 100 and a pulse motor 102.

[0054] like Figure 4 As shown, the support box 15 is formed into a roughly "U" shape when viewed from the side by an upper plate 15c, a lower plate 15e and a connecting plate 15b, and an opening 15g is formed on the side opposite to the connecting plate 15b. The downward shooting camera 82 can enter the space between the upper plate 15c and the lower plate 15e through the opening 15g.

[0055] Next, an example of a wafer processing method using the above-described device structure will be described.

[0056] <Wafer Preparation Step>

[0057] First, prepare Figure 5 (A) and Figure 5 FIG. 1 shows a wafer 10 as an example of a workpiece (B).

[0058] Figure 5 (A) shows the front side 10 a of the wafer 10 , where devices 11 are arranged in a grid pattern and are divided into chips by performing a dividing process such as cutting along the streets 13 .

[0059] Figure 5 (B) shows the back side 10b of the wafer 10, which has a concave portion 18 concentric with the disc-shaped wafer 10 and a peripheral convex portion 19 surrounding the concave portion 18. The concave portion 18 is formed in a portion corresponding to the device region where the device 11 is formed on the front side 10a. In addition, a metal film may be formed on the surface of the concave portion 18 or the peripheral convex portion 19.

[0060] <Protective Component Installation Step>

[0061] Regarding the above wafer 10, as Figure 6 As shown in (A), a transparent tape T is attached to the front surface 10a side of the wafer 10 as a protective member for protecting the device, and as shown in FIG. Figure 6 As shown in (B), the outer periphery of the tape T is affixed to the annular frame F to form the wafer unit 8. The term "transparent" for the tape T here refers to "transmitting light of at least a portion of the wavelengths of visible light without absorption or scattering." The tape T may be colored, as long as it can perform the peripheral protrusion detection step and the interval lane detection step described later. Furthermore, the protective member may be a rigid plate (glass, resin, etc.) in addition to a stretchable resin tape.

[0062] The tape T is composed of, for example, a base material such as vinyl chloride, polyethylene terephthalate (PET), or polyimide (PI) having a thickness of 10 μm to 200 μm, and an acrylic or rubber-based paste layer.

[0063] <Maintain Steps>

[0064] Then, if Figure 4 As shown, the wafer unit 8 is placed on the holding table 27, and the wafer 10 is held by the holding table 27 via the tape T. Specifically, the tape T of the wafer unit 8 is placed on the holding pad 74 of the holding table 27, and the suction source 80 is started to suck and hold the back side of the tape T through the fine holes 76. At this time, the annular frame F of the wafer unit 8 is placed on the frame support table 15d.

[0065] <Outer Peripheral Protrusion Detection Step>

[0066] Then, if Figure 4 As shown, the position of the outer peripheral protrusion 19 of the wafer 10 is detected by the overhead camera 52. Specifically, the image captured by the overhead camera 52 is analyzed to detect the position of the outer peripheral edge of the outer peripheral protrusion 19, that is, the position of the outer peripheral edge of the wafer. Furthermore, the width W of the outer peripheral protrusion 19 (the radial width of the wafer 10) and the wafer diameter are pre-identified as wafer 10 attribute information for each wafer type by the processing equipment.

[0067] Alternatively, the camera 52 ( Figure 4 ) is used to detect the position of the outer periphery of the peripheral protrusion 19, the lower shooting camera 82 is used to shoot the wafer 10 from the bottom, and the image thus shot is analyzed to detect the position of the outer periphery of the peripheral protrusion 19 (the outer periphery of the wafer). Figure 4 ) shooting, the upper shooting camera 52 ( Figure 4 ) settings.

[0068] <First Cutting Step>

[0069] Then, if Figure 7 As shown in FIG. 5A , the first cutting blade 50 of the first cutting unit 46 is positioned at the outer peripheral convex portion 19 , and the first cutting blade 50 is caused to cut into the outer peripheral convex portion 19 , thereby removing the outer peripheral convex portion 19 by cutting.

[0070] More specifically, the first cutting tool 50 positioned above the outer peripheral protrusion 19 is lowered to a first predetermined height to cut into the outer peripheral protrusion 19, and the holding table 27 is rotated to remove the outer peripheral protrusion 19 by cutting. Figure 3 As shown in (A), the motor 17 is driven to rotate the holding table 27 via the belt 29, thereby rotating the holding table 27. The first cutting tool 50 and the holding table 27 (peripheral protrusion 19) can be aligned using the coordinates of the outer peripheral edge of the peripheral protrusion 19 of the wafer 10 (the outer peripheral edge of the wafer) obtained in the above-mentioned peripheral protrusion detection step.

[0071] Here, the "first predetermined height" means that the first cutting blade 50 does not reach the back surface 10b of the device region (at Figure 7 In the example of (A), the height of the metal film 18 a is limited by the thickness of the wafer 10 and the depth of the recess 18 .

[0072] As described above, the outer peripheral protrusion 19 is removed to form Figure 7 In addition, Figure 7 (A) and Figure 7 In the wafer 10 shown in FIG. 1 (B), the metal film 18 a is formed within the concave portion 18 . However, the present invention is also applicable to a wafer 10 in which the metal film 18 a is not formed.

[0073] Alternatively, instead of strictly aligning the outer peripheral protrusion 19 with the first cutting tool 50 as described above and then performing the cutting removal, the following method may be employed. First, the first cutting tool 50 is positioned at the first predetermined height. Then, the X-axis direction movement of the holding table 27 is repeated ( Figure 1 ) and the Y-axis direction of the first cutting tool 50 ( Figure 1 ) is indexed and fed so as to relatively move the wafer 10 and the first cutting blade 50 over the entire range of the wafer 10. Thus, the outer peripheral convex portion 19 over the entire range of the wafer 10 can be removed.

[0074] In addition, in a structure in which the holding worktable 27 can rotate 360 ​​degrees, the peripheral protrusion detection step may not be implemented. Instead, the first cutting tool 50 is positioned at the outer peripheral edge of the chip 10 according to the diameter of the chip 10 and the center position of the holding worktable 27, and the holding worktable 27 is rotated within a range of 360 degrees, thereby implementing the first cutting step.

[0075] In addition, in a structure in which the holding worktable 27 can rotate 180 degrees, the peripheral protrusion detection step may not be implemented. Instead, the first cutting tool 50 is positioned at one end side of the peripheral edge of the chip 10 based on the diameter of the chip 10 and the center position of the holding worktable 27, and the holding worktable 27 is rotated clockwise within a range of 180 degrees. After the peripheral protrusion 19 of the chip 10 within a range of 180 degrees is removed, the first cutting tool 50 is positioned at the other end side facing the one end side with the center of the chip 10 clamped, and the holding worktable 27 is rotated counterclockwise within a range of 180 degrees to remove the remaining peripheral protrusion 19, thereby implementing the first cutting step.

[0076] In the above-described embodiment, imaging by the upper imaging camera 52 or the lower imaging camera 82 for detecting the outer peripheral edge of the outer peripheral convex portion 19 can be omitted, and the outer peripheral convex portion detection step can be omitted.

[0077] <Separate lane detection steps>

[0078] Then, if Figure 4 and Figure 8 As shown in (A), the Y-axis moving block 83 is moved to position the bottom shooting camera 82 below the wafer 10, and the front surface 10a of the wafer 10 (at the bottom) is viewed through the holding pad 74 and the tape T of the holding table 27. Figure 8 (A) is the lower side of the surface) to capture the spacer 13 of the wafer 10 ( Figure 5 (A)) was detected.

[0079] <Second Cutting Step>

[0080] Then, if Figure 8 As shown in (B), along the detected interval 13 ( Figure 5 (A)) and cutting processing is performed using the second cutting tool 50a of the second cutting unit 46a.

[0081] Before the cutting process is performed, alignment is performed. Figure 3 As shown in (A), the motor 17 is driven to rotate the holding table 27 via the belt 29 to change the angle so that the interval path 13 ( Figure 5 (A)) is parallel to the X-axis direction or the Y-axis direction, and the second cutting unit 46a is moved in the Y-axis direction, so that the spacing road 13 ( Figure 5 (A)) is consistent with the position of the second cutting tool 50a of the second cutting unit 46a.

[0082] After the alignment is performed, the second cutting tool 50a of the second cutting unit 46a is positioned at a second predetermined height so that the tip thereof cuts into the wafer, and the holding table 27 is moved in the X-axis direction ( Figure 1) to perform machining feed, and the second cutting unit 46a is moved in the Y-axis direction ( Figure 1 ) and indexing feed is performed on the wafer 10, and all the streets 13 extending in the first direction are cut using the second cutting tool 50a. Next, the holding table 27 is rotated 90 degrees, and all the streets 13 extending in a second direction perpendicular to the first direction are cut using the second cutting tool 50a. The second predetermined height is set to a height at which the tip of the tool penetrates the protective member, thereby dividing the wafer 10 into chips.

[0083] In this second cutting step, due to Figure 7 As shown in (B), the peripheral protrusion 19 is machined by the first cutting tool 50, and the thickness of the portion of the peripheral protrusion 19 is reduced. Therefore, there is no need to set the blade tip protrusion of the second cutting tool 50a too much, and cutting can be performed with an appropriate blade tip protrusion. In other words, if the peripheral protrusion 19 is present, it is necessary to cut the peripheral protrusion 19 so that the blade tip reaches the front side of the wafer 10. If the blade tip protrusion is set to a large amount, there is a concern that the cutting tool may break or vibrate. However, according to the embodiment of the present invention, such adverse conditions can be avoided. In addition, by reducing the blade tip protrusion, a thinner cutting tool can be selected, thereby achieving more precise cutting processing.

[0084] In the second cutting step, in addition to full cutting in which the wafer 10 is cut through in the thickness direction of the wafer 10 , half cutting in which the wafer 10 is cut to a position midway in the thickness direction of the wafer 10 may be performed.

[0085] As described above, the present invention can be achieved.

[0086] That is, Figures 1 to 8 As shown, according to one embodiment of the present invention, a processing device 2 is provided for processing a wafer 10. The wafer 10 has a recess 18 formed on a back surface 10b corresponding to a device region on a front surface 10a, and a peripheral protrusion 19 surrounding the recess 18 is formed on the back surface. In the device region, devices 11 are formed in respective regions divided by a plurality of intersecting spacing streets 13.

[0087] Wherein, the processing device 2 has:

[0088] A rotatable holding table 27 having a holding portion 74a made of a transparent material for holding the front surface 10a side of the wafer 10;

[0089] A lower shooting camera 82 that shoots the front surface 10a of the wafer 10 held by the holding table 27 through the holding portion 74a;

[0090] a cutting mechanism (a first cutting unit 46 and a second cutting unit 46a), comprising the first cutting unit 46 having a first cutting tool 50 for cutting the peripheral protrusion 19 of the back surface 10b of the wafer 10 to reduce the height of the peripheral protrusion 19, and the second cutting unit 46a having a second cutting tool 50a for cutting the wafer 10 along the streets 13 of the front surface 10a of the wafer 10 captured by the lower imaging camera 82; and

[0091] The moving mechanism 23 moves the holding table 27 relative to the cutting mechanism.

[0092] Thus, for the chip 10 having a circular recess 18 and a peripheral protrusion 19 formed on the back side 10b, the chip 10 can be singulated without removing the chip from the holding workbench 27, and the possibility of damage to the chip 10 caused when the chip 10 is removed from the holding workbench 27 and operated can be prevented.

[0093] Furthermore, since the first cutting tool 50 processes the outer peripheral protrusion 19, the thickness of the outer peripheral protrusion 19 portion is reduced. Therefore, it is not necessary to set the blade tip protrusion of the second cutting tool 50a excessively, and cutting can be performed with an appropriate blade tip protrusion. This can prevent the occurrence of problems such as chipping and shaking of the cutting tool.

[0094] In addition, if Figure 4 As shown, it is preferable to further include an upper imaging camera 52 for imaging the back surface 10 b of the wafer 10 held by the holding stage 27 .

[0095] Thus, the position of the outer peripheral convex portion 19 can be detected, and the outer peripheral convex portion 19 can be machined by aligning the position of the first cutting blade 50 with the outer peripheral convex portion 19 .

[0096] In addition, if Figures 1 to 8 According to another embodiment of the present invention, a processing method is provided, wherein:

[0097] The processing method comprises the following steps:

[0098] a step of preparing a wafer 10, wherein the wafer 10 has a recess 18 formed on a back surface 10b corresponding to a device region of the front surface 10a, and a peripheral protrusion 19 formed around the recess 18, wherein the device 11 is formed in each region divided by a plurality of intersecting spacing streets 13 in the device region;

[0099] a protective member disposing step of disposing a transparent protective member (with a T) on the front surface 10a of the wafer 10;

[0100] A holding step in which the front surface 10a side of the wafer 10 is held via a protective member using the holding table 27;

[0101] In the first cutting step, the front end of the first cutting tool 50 is cut into the outer peripheral protrusion 19 of the wafer 10 held by the holding table 27 to a height that does not reach the bottom surface of the recess 18, thereby reducing the height of the outer peripheral protrusion 19;

[0102] a street inspection step, after the first cutting step is performed, using the bottom camera 82 to photograph the front surface 10a of the wafer 10 through the holding portion 74a and the protective member, thereby inspecting the street 13; and

[0103] In the second cutting step, the wafer 10 is cut using the second cutting blade 50a along the streets 13 detected in the street detection step.

[0104] Thus, for the chip 10 having a circular recess 18 and a peripheral protrusion 19 formed on the back side 10b, the chip 10 can be singulated without removing the chip from the holding workbench 27, and the possibility of damage to the chip 10 caused when the chip 10 is removed from the holding workbench 27 and operated can be prevented.

Claims

1. A method for processing a wafer, wherein: The wafer processing method has the following steps: a wafer preparation step of preparing a wafer having a concave portion formed on a back surface corresponding to a device region on the front surface and a peripheral convex portion formed on the back surface surrounding the concave portion, wherein devices are formed in respective regions divided by a plurality of intersecting spacing streets in the device region; a protective member disposing step of disposing a transparent protective member on the front surface of the wafer; a holding step of holding the front side of the wafer via the protective member using a holding table having a rotatable holding portion made of a transparent material; A first cutting step of cutting the outer peripheral convex portion of the wafer held by the holding table by cutting the front end of a first cutting tool to a height that does not reach the bottom surface of the concave portion, thereby reducing the height of the outer peripheral convex portion; a street detection step of detecting the street by photographing the front surface of the wafer through the transparent holding portion and the transparent protective member using a bottom camera disposed below the holding table after the first cutting step is performed; and a second cutting step of cutting the wafer along the streets detected by the street detection step using a second cutting tool; The wafer is always held by the holding table during the first cutting step, the street inspection step, and the second cutting step.

2. A processing device for implementing the wafer processing method according to claim 1, wherein the processing device processes a wafer having a concave portion formed on a back surface corresponding to a device region on the front surface, and a peripheral convex portion surrounding the concave portion formed on the back surface, wherein devices are formed in each region divided by a plurality of intersecting spacing streets in the device region, wherein: The processing device has: a rotatable holding table having a holding portion made of a transparent material for holding the front side of the wafer; a bottom shooting camera for shooting the front surface of the wafer held by the holding table through the holding portion; a cutting mechanism comprising a first cutting unit and a second cutting unit, the first cutting unit having a first cutting tool for cutting the peripheral convex portion on the back side of the wafer to reduce the height of the peripheral convex portion, and the second cutting unit having a second cutting tool for cutting the wafer along the street on the front side of the wafer photographed by the lower photographing camera; and A moving mechanism enables the holding table and the cutting mechanism to move relative to each other.

3. The processing device according to claim 2, wherein: The processing apparatus further includes an upper imaging camera for imaging the back surface of the wafer held by the holding table.

Images