Method for processing a workpiece

Abstract

The present application provides a machining method of a workpiece, which includes a cutting step of forming a cutting groove and a cleaning step of performing spin cleaning thereafter, and is used to more reliably flush away cutting chips generated in the cutting step so as not to remain in the cutting groove. The machining method of the workpiece includes the steps of: a cutting step of cutting the workpiece along a division predetermined line using a cutting tool having a V shape at a front end to form a V groove whose width of a groove shallow portion is wider than that of a groove deep portion; and a cleaning step of cleaning a back surface of the workpiece using cleaning water after the cutting step is performed.

Description

Technical Field

[0001] The present invention relates to a method for processing a workpiece having a front surface on which devices are formed in regions divided by a plurality of intersecting planned dividing lines. Background Art

[0002] Conventionally, there is known a cutting device for cutting a semiconductor wafer having a front surface with devices formed in regions divided by a plurality of intersecting predetermined dividing lines as a workpiece, and cutting the workpiece along the predetermined dividing lines using a high-speed rotating cutting tool.

[0003] For example, Patent Document 1 discloses a cutting device comprising: a chuck table for holding a wafer unit; a cutting unit for cutting the wafer; and a cleaning unit for cleaning the wafer. In this cutting device, after a cut groove is formed on the wafer by cutting, the cleaning unit cleans the wafer.

[0004] The cleaning unit is configured to spin the wafer at high speed while holding it on a rotating table mechanism, spraying cleaning fluid from a cleaning fluid nozzle positioned above the wafer. This cleaning method is known as spin cleaning, and it removes chips (foreign matter, contaminants) that adhere to the wafer during the cutting process.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-46485

[0006] In the above-mentioned spin cleaning, the cleaning liquid is supplied from above the rotating workpiece, so that the cleaning liquid has difficulty entering the cut grooves. As a result, the chips that have entered the cut grooves may remain without being washed away.

[0007] After the wafer is divided along the predetermined dividing lines and individualized into chips, the shavings remain attached to the sides of the chips and may fall off during pickup and adhere to the components, damaging them and causing device failure. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a method for processing a workpiece, which includes a cutting process for forming a cutting groove and a cleaning process for performing rotary cleaning thereafter, wherein the method for processing the workpiece is used to more reliably wash away the cutting chips generated in the cutting process so that the cutting chips do not remain.

[0009] According to the present invention, a method for processing a workpiece is provided, wherein the workpiece has a front side on which devices are formed in an area divided by a plurality of intersecting predetermined dividing lines, and a back side located on the opposite side of the front side, wherein the method for processing the workpiece has the following steps: a workpiece preparation step, wherein a tape that is transparent to visible light is attached to the front side of the workpiece; a holding step, wherein the front side of the workpiece is held via the tape using a holding worktable having a holding component, at least a portion of the holding component being transparent; a predetermined dividing line position detection step, wherein after the holding step is performed, the front side of the workpiece held by the holding worktable is photographed via the holding component and the tape using a camera to detect the position of the predetermined dividing line; a cutting step, wherein after the predetermined dividing line position detection step is performed, the workpiece is cut along the predetermined dividing line using a cutting tool having a V-shaped front end to form a V-groove, wherein the width of the shallow portion of the V-groove is wider than the width of the deep portion of the groove; and a cleaning step, wherein after the cutting step is performed, the back side of the workpiece is cleaned using a cleaning liquid.

[0010] According to the present invention, a groove is formed in which the width of the shallow portion is wider than the width of the deep portion. Therefore, during the cleaning step, the cleaning fluid easily enters the groove, reliably flushing away any chips that have entered the groove, thereby preventing the chips from remaining on the side or back of the chip. Furthermore, the cutting fluid that has entered the groove can be easily discharged along with the chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view of one embodiment of a cutting device used in practicing the present invention.

[0012] Figure 2 This is an exploded perspective view of the support box and the holding table.

[0013] Figure 3 (A) is a perspective view of the holding table mounted on the support box. Figure 3 (B) is a three-dimensional diagram of the lower shooting mechanism and its supporting structure.

[0014] Figure 4 It is a diagram showing the cross-sectional shape of the holding table, etc.

[0015] Figure 5 (A) is a side view schematic diagram showing the structure of the lower shooting mechanism, Figure 5 (B) is a side view showing another embodiment of the prism body.

[0016] Figure 6 This is a front schematic diagram showing the structure of the lower imaging mechanism.

[0017] Figure 7 (A) is a perspective view showing the front side of a wafer as an example of a workpiece. Figure 7 (B) is a perspective view showing the back surface of a wafer as an example of a workpiece.

[0018] Figure 8 It is a partially cutaway side view showing the positional relationship between the holding table and the lower imaging mechanism.

[0019] Figure 9 It is a partially cutaway side view illustrating the cutting step.

[0020] Figure 10 It is a partially cutaway side view of the rotary cleaning unit.

[0021] Figure 11 (A) is a cross-sectional view showing a cutting step for forming a V-shaped groove. Figure 11 (B) is a cross-sectional view showing a state in which the wafer is divided into chips by a cutting step.

[0022] Figure 12 (A) is a cross-sectional view showing a cutting step for forming a V-shaped groove. Figure 12 (B) is a cross-sectional view showing a case where full cutting is performed to form a linear groove.

[0023] Figure 13 is a partially cutaway side view illustrating the cleaning step.

[0024] Description of labels

[0025] 2: Cutting device; 5: Chip; 5a: Side; 8: Wafer unit; 10: Substrate; 10a: Front; 10b: Back; 11: Device; 13: Predetermined dividing line; 27: Holding table; 46: Cutting unit; 74: Holding component; B1: Cutting tool; C: Shooting camera; F: Ring frame; M: Groove; T: Belt; W: Wafer; Wa: Front; Wb: Back. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 2 is a perspective view showing a cutting device 2 according to an embodiment of the present invention. In addition to the cutting device described below, the present invention can also be applied to a laser processing device having a processing unit that processes a workpiece using a laser beam and includes a laser oscillator that oscillates laser light and a condenser that focuses the laser beam onto the workpiece.

[0027] like Figure 1 As shown, on the base 4 of the cutting 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 water cover 14 is provided around the holding table 27, and a bellows portion 16 is connected between the water cover 14 and the base 4.

[0028] 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 .

[0029] 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 Y-axis moving block 28 is movably mounted on the guide rails 26. The Y-axis moving block 28 is guided by the guide rails 26 and moves in the Y-axis direction via a Y-axis moving mechanism 34 composed of a ball screw 30 and a pulse motor 32.

[0030] like Figure 1 As shown, a pair of guide rails 36 extending in the Z-axis direction are fixed to the Y-axis moving block 28. The Z-axis moving block 38 is movably provided on the guide rails 36. The Z-axis moving block 38 is guided by the guide rails 36 and moves in the Z-axis direction by a Z-axis moving mechanism 44 composed of a ball screw 40 and a pulse motor 42.

[0031] The cutting unit 46 and the upper shooting mechanism 52 are mounted on the Z-axis moving block 38. Figure 9 As shown, the cutting unit 46 is configured such that a cutting tool B1 is detachably mounted on a front end portion of a spindle 48 that is rotationally driven by a motor (not shown).

[0032] like Figure 1 As shown, a spin cleaning unit 54 having a spin table 56 is provided on the base 4 . The spin table 56 can suck and hold the workpiece after cutting to perform spin cleaning and spin drying.

[0033] Figure 2 This figure illustrates the structure of the holding table 27. The holding table 27 comprises an annular base 62 and a disc-shaped holding member 74. The annular base 62 includes a fitting portion 64, a tape winding portion 66 having a larger diameter than the fitting portion 64, a through portion 65 extending axially through the fitting portion 64, and a transparent member 68 sealing the through portion 65.

[0034] like Figure 2 As shown, a mounting area 70 for placing and fixing a frame portion 74 b of a disc-shaped holding member 74 is provided on the upper surface of the annular base 62 .

[0035] like Figure 2As shown, the holding member 74 is constructed to have a disc-shaped holding portion 74a and a frame portion 74b surrounding the holding portion 74a. The holding portion 74a is formed using a transparent member such as quartz glass, borosilicate glass, sapphire, calcium fluoride, lithium fluoride, magnesium fluoride, etc. In addition, the "transparency" of the transparent member means "allowing light of at least a portion of the wavelength of visible light to pass through without absorption or scattering", and it can be a colored member as long as it can perform the peripheral convex portion detection step and the dividing predetermined line detection step described later. In addition, the transparent area can be formed only in a required range of a part of the holding member 74. As described above, the transparent area is formed on the holding workbench 27 using the holding portion 74a of the holding member 74.

[0036] like Figure 4 As shown, the upper surface of the holding portion 74a forms a holding surface 74c for holding the wafer W. A plurality of annular suction grooves 76 (three rows in this embodiment) are concentrically provided on the holding surface 74c near the outer periphery of the holding portion 74a. The tape T is held by suction by these suction grooves 76. When the holding member 74 is attached to the annular base 62, the suction grooves 76 are connected to a suction source 89.

[0037] like Figure 2 and Figure 4 As shown, frame support portions 72 are provided at four locations on the upper surface of the annular base 62 so as to surround the periphery of the holding member 74 . The frame support portions 72 support the annular frame F of the wafer unit 8 from below.

[0038] The frame support portion 72 includes a support block 72 a constituting a support surface for supporting the annular frame F and an adsorption portion 72 b for adsorbing and holding the annular frame F from the lower side. The adsorption portion 72 b is connected to a suction source 89 .

[0039] The annular base 62 of the holding table 27 is formed with a through-portion 65 having a diameter substantially identical to that of the holding portion 74a of the holding member 74. The lower portion of the through-portion 65 is sealed with a transparent member 68 (e.g., glass). Thus, the transparent member 68, the through-portion 65, and the holding portion 74a of the holding member 74 are arranged in this order from the bottom. Light passes through these portions, enabling imaging from below the holding table 27, as described in detail below. Alternatively, the transparent member 68 may be omitted.

[0040] like Figure 2 As shown, the holding member 74 is mounted on the mounting area 70 of the annular base 62, and the annular fitting portion 64 protruding downward from the annular base 62 is fitted into the circular opening 15a of the support box 15, so that 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 .

[0041] like Figure 3 As shown in FIG. 1A , a motor 17 is mounted on the connecting plate 15 b of the support box 15, and a belt 29 is wound around a pulley 17 a connected to the output shaft of the motor 17 and the belt winding portion 66 of the annular base 62. When the motor 17 is driven, the holding table 27 is rotated by the belt 29.

[0042] Figure 3 The motor 17 shown in (A) 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 7 Alignment of the planned dividing lines (streets) 13 of the wafer W shown in (A).

[0043] 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 .

[0044] The ball screw 23a is screwed into an internal 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.

[0045] A lower imaging mechanism 82 is provided near the support box 15 to capture an image of a workpiece such as a semiconductor wafer held by the holding table 27 from below the holding member 74 .

[0046] like Figure 8 As shown, the support box 15 is formed into a roughly "U" shape when viewed from the side using the upper plate 15c, the lower plate 15e and the connecting plate 15b. An opening 15g is formed on the opposite side of the connecting plate 15b to allow the lower camera mechanism 82 to enter the space between the upper plate 15c and the lower plate 15e.

[0047] like Figure 3 (A) and Figure 3 As shown in FIG. 8 (B), the lower imaging mechanism 82 is provided on a column 96 provided upright on the Y-axis moving block 83. The Y-axis moving block 83 is slidably mounted on a pair of guide rails 81 fixedly extending in the Y-axis direction and is moved in the Y-axis direction by a drive unit 87. The drive unit 87 includes a pulse motor 87b and a ball screw 87a arranged parallel to the guide rails 81.

[0048] like Figure 3As shown in FIG. 8A , the ball screw 87 a is screwed into the internal thread portion provided on the lower surface of the Y-axis moving block 83 , and the pulse motor 87 b is driven to rotate the ball screw 87 a , thereby moving the Y-axis moving block 83 in the Y-axis direction.

[0049] like Figure 3 As shown in FIG. 8 (B), the lower imaging mechanism 82 is configured to include a prism mechanism P and an imaging camera C.

[0050] like Figure 5 (A) and Figure 6 As shown, the prism mechanism P includes a prism body 90 , a light source 92 , and a housing 84 that houses the prism body 90 and the light source 92 .

[0051] The prism body 90 of the prism mechanism P is composed of a so-called right-angle prism (a right-angled triangle in side view) having a reflecting surface 90 a inclined at an angle of approximately 45 degrees in side view.

[0052] like Figure 5 As shown in FIG. 8A , a first through-hole 88a is formed in the housing 84 at an upper position inclined 45 degrees relative to the reflecting surface 90a, that is, at an upper position relative to the prism body 90. The reflecting surface 90a faces the holding stage 27 through the first through-hole 88a.

[0053] The housing 84 has a second passage opening 88 b formed at a lower position inclined at 45 degrees with respect to the reflecting surface 90 a , that is, at a position lateral to the prism body 90 .

[0054] like Figure 5 As shown in FIG. 8A , the light H1 entering from the first passage opening 88 a is reflected by the reflection surface 90 a and refracted 90 degrees, and then exits from the second passage opening 88 b .

[0055] In addition, in addition to Figure 5 In addition to directly reflecting the light H1 by the reflection surface 90a as in the prism body 90 shown in FIG. Figure 5 As in the prism body 90A shown in FIG. 2 (B), the light H1 is transmitted through the prism body 90A and refracted by the reflection surface 90b. In this case, the optical path length can be made longer, and a design can be made to avoid interference between components.

[0056] like Figure 5 (A) and Figure 6As shown, a light source 92, such as an LED, is housed in a housing 84, and a light transmission opening 86 for transmitting light from the light source 92 is formed on the upper surface of the housing 84. In this embodiment, three light sources 92 are arranged on each side of the prism body 90, and a light transmission opening 86 is formed at a position corresponding to each light source 92.

[0057] like Figure 6 As shown, the light H2 irradiated from the light source 92 is irradiated toward the lower surface of the wafer W held by the holding table 27 arranged above, and the reflected light H1 is incident on the prism body 90. In addition, the light source 92 illuminates the imaging camera C ( Figure 5 The focal position of (A)) is tilted and arranged, and the optical axis of the light H2 is tilted.

[0058] like Figure 5 As shown in FIG. 8 (A), the imaging camera C includes a lens barrel 91 , an objective lens 93 provided on one end side of the lens barrel 91 , and an imaging element 95 provided on the other end side of the lens barrel 91 .

[0059] The lens barrel 91 is provided so as to be connected to the second through port 88 b , and the objective lens 93 is arranged so as to face the reflection surface 90 a of the prism body 90 .

[0060] The light H1 that has passed through the objective lens 93 is received by the imaging element 95 and converted into image data by an image processing device (not shown).

[0061] like Figure 3 As shown in (B), the prism mechanism P and the photographing camera C constituting the lower photographing mechanism 82 are supported by a support plate 94, and the base end of the support plate 94 is fixed to the Z-axis moving block 98. Figure 3 A Z-axis moving unit 104 composed of a ball screw 100 and a pulse motor 102 is provided on the column 96 of (A), and the Z-axis moving block 98 moves in the Z-axis direction (up and down direction) along a pair of guide rails 106, and the lower shooting mechanism 82 also moves in the Z-axis direction (up and down direction).

[0062] Figure 10 It is a partial side cross-sectional view of a spin cleaning unit 54 for cleaning a wafer W. The spin cleaning unit 54 includes a rotary table mechanism 154 and a liquid receiving mechanism 156 disposed so as to surround the rotary table mechanism 154 .

[0063] The rotary table mechanism 154 includes a rotary table (holding table) 158 that suction-holds the wafer W, a support member 160 that supports the rotary table 158 , and a motor 162 that rotationally drives the rotary table 158 via the support member 160 .

[0064] The fixtures 144 are provided on the rotating table 158. When the rotating table 158 rotates, the fixtures 144 swing due to the centrifugal force. Figure 7 The annular frame F shown in (B) is clamped and held.

[0065] The liquid receiving mechanism 156 includes a liquid receiving container 156 a and a cover member 156 b attached to the support member 160 , and is configured to receive liquid such as a cleaning liquid and discharge the waste liquid through a discharge path (not shown).

[0066] A cleaning liquid discharge nozzle 170 for discharging cleaning liquid 140 is provided in the space surrounded by liquid receiving container 156a. Cleaning liquid discharge nozzle 170 is formed at the front end of a generally L-shaped arm 171. The other end of arm 171 is swung by a motor 172. Arm 171 is connected to a cleaning liquid supply source 175 via a cleaning liquid supply path 173 and an on / off control valve 174. Cleaning liquid 140 is, for example, pure water.

[0067] Furthermore, a dry air ejection nozzle 180 for ejecting dry air is provided in the space surrounded by the liquid receiving container 156a.

[0068] Dry air nozzle 180 is formed at the front end of a substantially L-shaped arm 181, and the other end of arm 181 is swung by motor 182. Arm 181 is connected to dry air supply source 185 via dry air supply path 183 and opening and closing control valve 184.

[0069] In the spin cleaning unit 54 having the above structure, the cleaning liquid spray nozzle 170 is first positioned above the wafer W, and the wafer W is rotated at a predetermined speed, and the cleaning liquid 140 is sprayed toward the wafer W for spin cleaning.

[0070] After the spin cleaning is performed, the dry air ejection nozzle 180 is positioned above the wafer W, and the wafer W is rotated at a predetermined speed to blow dry air toward the wafer W, thereby performing spin drying.

[0071] Next, a processing example using the above-described device configuration will be described.

[0072] <Workpiece preparation steps>

[0073] In this step, a tape that is transparent to visible light is attached to the front surface of the workpiece. Figure 7 FIG. (A) shows a wafer W as an example of a workpiece. The wafer W has a metal film 12 formed as an electrode or a die-bonding material on the back surface 10 b of a substrate 10 formed of, for example, a semiconductor.

[0074] like Figure 7 As shown in FIG. 1A , devices 11 are arranged in a grid pattern on a front surface 10a of a substrate 10 constituting a wafer W. The wafer W is divided into chips by cutting along predetermined dividing lines 13 (streets). The substrate 10 is, for example, a 100 μm thick SiC wafer.

[0075] Figure 7 (B) shows the back side of the wafer W. A metal film 12 is formed on the back side 10b of the substrate 10 constituting the wafer W. The material, structure, thickness, etc. of the metal film 12 are not particularly limited, and examples thereof include a stacked structure of titanium and copper; a stacked structure of nickel, platinum, and gold; a stacked structure of nickel and gold; or a single layer structure of silver.

[0076] In addition, if Figure 7 As shown in FIG. 8 (B), the metal film 12 is exposed on the upper side, and the front surface Wa of the wafer W is attached to the tape T, so that the ring frame F and the wafer W are integrated with each other via the tape T to form a wafer unit 8.

[0077] By configuring the wafer unit 8 as described above, the device 11 on the front surface Wa can be protected by the tape T and the wafer W can be handled. Alternatively, the front surface Wa of the wafer W may be protected by attaching a tape to the tape without using the ring frame F.

[0078] In addition, Figure 7 In (B), the tape T has a transparent property, namely, "transmits light of at least a portion of the visible wavelengths without absorption or scattering," enabling the subsequent step of detecting the planned dividing line. The tape T can also be colored or made of a stretchable resin. Alternatively, a rigid plate made of glass, resin, or the like can be used to protect the front surface Wa of the wafer W during operation, instead of the tape T.

[0079] Furthermore, the workpiece is also applicable to workpieces without the metal film 12. That is, the present invention can be widely and appropriately applied to applications where the front surface Wa with the device 11 formed thereon is attached to the tape T for protection and the planned dividing line of the front surface Wa is imaged.

[0080] <Maintaining steps>

[0081] like Figure 8 As shown, in this holding step, the front surface Wa side of the wafer W is held via the tape T by the holding table 27 having a holding member 74 , at least a portion of which is transparent.

[0082] The wafer W is sucked and held by the holding member 74 of the holding table 27 via the tape T. The tape T and the holding member 74 are transparent as described above.

[0083] <Split Planned Line Detection Procedure>

[0084] like Figure 8 As shown, after the holding step is implemented, in the predetermined dividing line detection step, the camera C ( Figure 5 (A)) The front surface Wa of the wafer W held by the holding table 27 is photographed through the holding member 74 and the tape T, and the predetermined dividing line 13 ( Figure 7 The position of (A)) is detected.

[0085] Specifically, if Figure 8 As shown, the Y-axis moving block 83 is moved to position the lower imaging mechanism 82 below the wafer W, and the front surface Wa of the wafer W is imaged through the holding member 74 of the holding table 27 and the tape T, and the predetermined dividing line 13 ( Figure 7 (A)).

[0086] <Cutting steps>

[0087] like Figure 11 (A) and Figure 11 As shown in (B), after the predetermined dividing line position detection step is implemented, in the cutting step, the workpiece (wafer W) is cut along the predetermined dividing line 13 using a cutting tool B1 with a V-shaped front end to form a groove M1 in which the width of the shallow part of the groove is wider than the width of the deep part of the groove.

[0088] Specifically, if Figure 9 As shown, the position of the cutting tool B1 of the cutting unit 46 is aligned with the predetermined dividing line 13 ( Figure 7 The position of (A)) is aligned, and the cutting unit 46 is positioned at a predetermined height, and the holding table 27 is moved in the processing feed direction (X-axis direction) to perform cutting processing.

[0089] like Figure 9 As shown, when a predetermined dividing line 13 ( Figure 7 After the cutting process is performed on (A), the cutting tool B1 is indexed and fed in the Y-axis direction to perform the cutting process on the adjacent planned dividing lines in the same manner.

[0090] exist Figure 7 In (A), after all the planned dividing lines 13 extending in the first direction are cut, the holding table 27 ( Figure 9 ) rotate 90 degrees, Figure 7 The same cutting process is performed in the second direction of (A).

[0091] Through the above cutting process, Figure 11 (A) and Figure 11 In the example shown in (B), a V-shaped groove M1 is formed in which the width of the shallow portion is wider than the width of the deep portion, and full cutting is performed so that the groove M1 penetrates the wafer 10 and reaches the tape T. As a result, chips 5, 5 are formed on both sides of the groove M1, and the side surfaces 5a of each chip 5, 5 become inclined surfaces.

[0092] In addition, you can also Figure 12 (A) and Figure 12 As shown in (B), as a first cutting step, a cutting tool B2 with a V-shaped front end is used to perform half cutting of the chip W along the predetermined dividing line 13 to form a V-shaped groove M2. As a second cutting step, a cutting tool B3 with a straight front end is used to cut off the remaining part to perform full cutting to form a straight groove M3.

[0093] According to the step-cutting method of cutting in stages, it is also possible to form a V-shaped groove M2 in which the width of the shallow part of the groove is wider than the width of the deep part of the groove. Figure 1 The cutting device 2 shown uses a cutting device having two cutting tools.

[0094] Cleaning steps

[0095] like Figure 13 As shown, after the cutting step is performed, in this cleaning step, a cleaning liquid 140 is supplied to the back surface Wb of the wafer W to clean the workpiece.

[0096] During this cleaning, since the groove M1 is formed into a V-shaped cross section, the cleaning liquid 140 easily enters the groove M1 and can reliably wash away the cutting chips that have entered the groove M1, thereby preventing the cutting chips from remaining on the side surface 5a or back surface 5b of the chip 5.

[0097] According to the above embodiment, Figure 13 As shown, since the groove M1 is formed with a width of the shallow portion being wider than the width of the deep portion, the cleaning fluid 140 can easily enter the groove during the cleaning step, and can reliably wash away the cutting chips that have entered the groove M1, thereby preventing the cutting chips from remaining on the side surface 5a or back surface 5b of the chip 5. In addition, the cutting fluid that has entered the groove can also be easily discharged together with the cutting chips.

Claims

1. A method for processing a workpiece, wherein the workpiece has a front surface on which a device is formed and a back surface located on the opposite side of the front surface in an area divided by a plurality of intersecting predetermined dividing lines, wherein: The processing method of the workpiece has the following steps: In a workpiece preparation step, a tape having a transmittance to visible light is attached to the front surface of the workpiece; a holding step of holding the front side of the workpiece via the belt using a holding table having a holding member, at least a portion of which is transparent; a predetermined dividing line position detecting step, after the holding step is performed, photographing the front surface of the workpiece held by the holding table via the holding member and the belt using a photographing camera to detect the position of the predetermined dividing line; A first cutting step, after the step of detecting the position of the predetermined dividing line, is performed by cutting along the predetermined dividing line from the back side of the workpiece using a cutting tool having a V-shaped tip, thereby performing a half-cut to form a V-shaped groove, wherein the width of the shallow portion of the V-shaped groove is wider than the width of the deep portion of the groove; In the second cutting step, the remaining portion is cut off using a cutting tool having a straight tip, thereby performing full cutting to form a straight groove; as well as A cleaning step, after the second cutting step is performed, cleaning the back surface of the workpiece with a cleaning liquid while the front surface of the workpiece is protected by the belt.

2. A method for processing a workpiece having a front surface on which a device is formed and a back surface located on the opposite side of the front surface in an area divided by a plurality of intersecting predetermined dividing lines, wherein: The processing method of the workpiece has the following steps: In a workpiece preparation step, a tape having a transmittance to visible light is attached to the front surface of the workpiece; a holding step of holding the front side of the workpiece via the belt using a holding table having a holding member, at least a portion of which is transparent; a predetermined dividing line position detecting step, after the holding step is performed, photographing the front surface of the workpiece held by the holding table via the holding member and the belt using a photographing camera to detect the position of the predetermined dividing line; a cutting step of cutting along the predetermined dividing line from the back side of the workpiece using a cutting tool having a V-shaped tip, after the predetermined dividing line position detection step is performed, to form a groove reaching the belt, wherein the width of the shallow portion of the groove is wider than the width of the deep portion of the groove; as well as A cleaning step is performed after the cutting step, in which the back surface of the workpiece is cleaned with a cleaning liquid while the front surface of the workpiece is protected by the belt.

3. The method for processing a workpiece according to claim 1 or 2, wherein: In the workpiece preparation step, the tape is attached to the front surface of the workpiece in a state where grooves have not been processed on the front surface.

Images