Wafer processing method

Abstract

To provide a wafer processing method capable of reducing the consumption of a cleaning liquid without increasing the probability of contamination of chips with a device.SOLUTION: Edge trimming of a wafer is performed while a film of cleaning liquid covering the surface of the wafer is formed by supplying cleaning liquid to the center of the surface of the wafer and rotating the wafer. This can prevent the surface of the wafer from drying out and reduce the probability of chips entering the device. In addition, the consumption of the cleaning liquid can be reduced compared to a case in which the edge trimming of the wafer is performed while the cleaning liquid in the form of a curtain is supplied over the entire surface of the wafer.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for processing a wafer having chamfered outer peripheral ends.

Background Art

[0002] Chips of devices such as IC (Integrated Circuit) and LSI (Large Scale Integration) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by forming a large number of devices on the surface of a wafer made of a semiconductor material and then dividing the wafer into regions each containing an individual device.

[0003] In wafers used for manufacturing chips, cracks are likely to occur at the outer peripheral ends where stress concentrates. Therefore, in the chip manufacturing process, it is common for the outer peripheral ends to be chamfered prior to various processes. Further, in the chip manufacturing process, for the purpose of miniaturizing the manufactured chips, etc., the back side of the wafer is often ground to thin the wafer prior to dividing the wafer.

[0004] However, when the back side of a wafer having chamfered outer peripheral ends is ground to thin the wafer, the back side of the outer peripheral ends becomes a shape like a knife edge. And stress concentrates on this portion and cracks are likely to occur. Therefore, in the chip manufacturing process, edge trimming of the wafer is often performed after forming devices on the front side of the wafer and before grinding the back side of the wafer.

[0005] Edge trimming of a wafer is performed, for example, by cutting and removing a part of the front side of the outer peripheral end of the wafer. In this case, chips (cutting chips) of the wafer being cut off are generated. And if the cutting chips are mixed into the devices formed on the front side of the wafer, the quality of the chips obtained by dividing this wafer may deteriorate.

[0006] In view of this, it has been proposed to perform wafer edge trimming while supplying a liquid (cleaning solution) in a curtain-like manner over the entire surface of the wafer (see, for example, Patent Document 1). This prevents the wafer surface from drying out and reduces the likelihood of cutting debris contaminating the device. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-225612 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, when wafer edge trimming is performed while supplying cleaning fluid in this manner, the amount of cleaning fluid consumed increases, and the manufacturing cost of the chips produced by dividing this wafer also increases. In view of this, the object of the present invention is to provide a wafer processing method that can reduce the amount of cleaning fluid consumed without increasing the probability of cutting debris contaminating the device. [Means for solving the problem]

[0009] According to the present invention, a method for processing a wafer on which a plurality of devices are formed on the surface side and the outer edge is chamfered, wherein the wafer is rotatable along the circumferential direction and the surface is facing upward. On the upper surface of the porous plate The wafer SuctionA wafer processing method is provided, comprising: a holding step of holding the wafer; and, after the holding step, a processing step of processing the outer edge of the wafer while the lower end of the first cutting blade, which rotates while supplying cutting fluid from a first liquid supply unit provided around the annular first cutting blade, has cut into the outer edge of the wafer, and while supplying cleaning fluid to the center of the surface of the wafer from a second liquid supply unit provided around an annular second cutting blade, which is provided separately from the first cutting blade, and rotating the wafer to form a film of cleaning fluid that covers the surface of the wafer.

[0010] Furthermore, it is preferable that the present invention further comprises an ultraviolet irradiation step of irradiating the surface of the wafer with ultraviolet light before the processing step to impart hydrophilicity.

[0011] Furthermore, in the processing step, it is preferable that a cutting step, which increases the depth from the surface of the outer edge of the wafer at the lower end of the rotating cutting blade, and a rotation step, which rotates the wafer at least once, are performed alternately and repeatedly. [Effects of the Invention]

[0012] In this invention, wafer edge trimming is performed while a cleaning solution is supplied to the center of the wafer surface and the wafer is rotated, thereby forming a film of the cleaning solution that covers the wafer surface.

[0013] As a result, in the present invention, it is possible to prevent the wafer surface from drying out and reduce the likelihood of cutting debris contaminating the device. Furthermore, in the present invention, the amount of cleaning solution consumed can be reduced compared to the case in which wafer edge trimming is performed while supplying a curtain-like cleaning solution to the entire surface of the wafer. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic perspective view showing an example of a cutting apparatus. [Figure 2] FIG. 2(A) is a top view schematically showing an example of a wafer, and FIG. 2(B) is a cross-sectional view schematically showing an example of a wafer. [Figure 3] FIG. 3 is an exploded perspective view schematically showing the components of the cutting unit. [Figure 4] FIG. 4 is a side view schematically showing the components of the liquid supply unit. [Figure 5] FIG. 5 is a flowchart schematically showing an example of a method for processing a wafer. [Figure 6] Each of FIGS. 6(A), 6(B), and 6(C) is a partial cross-sectional front view schematically showing the state of the processing step. [Figure 7] FIG. 7 is a front view schematically showing the state of the ultraviolet irradiation step.

MODE FOR CARRYING OUT THE INVENTION

[0015] Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an example of a cutting apparatus in which edge trimming of a wafer is performed. The X-axis direction (front-rear direction) and the Y-axis direction (left-right direction) shown in FIG. 1 are directions orthogonal to each other on a horizontal plane, and the Z-axis direction (vertical direction) is a direction orthogonal to the X-axis direction and the Y-axis direction (vertical direction).

[0016] The cutting apparatus 2 shown in FIG. 1 has a base 4 that supports each component. On the base 4, a ball screw type X-axis movement mechanism 6 is provided. Specifically, the X-axis movement mechanism 6 has a pair of guide rails 8 extending along the X-axis direction.

[0017] An X-axis movement plate 10 is connected to the upper surface side of this pair of guide rails 8 in a slidable manner. Also, a screw shaft 12 extending along the X-axis direction is disposed between the pair of guide rails 8.

[0018] And, a motor 14 for rotating the screw shaft 12 is connected to one end of the screw shaft 12. Further, on the outer peripheral surface of the screw shaft 12 where the screw thread is formed, a nut portion (not shown) for accommodating balls that circulate in accordance with the rotation of the screw shaft 12 is provided, and a ball screw is constituted.

[0019] Also, this nut portion is fixed to the lower surface side of the X-axis moving plate 10. Therefore, if the screw shaft 12 is rotated by the motor 14, the X-axis moving plate 10 moves along the X-axis direction together with the nut portion.

[0020] Around the X-axis moving mechanism 6, a water case 16 for temporarily storing the liquid supplied when cutting the wafer is provided. The liquid stored in the water case 16 is discharged to the outside of the cutting device 2 through a drain (not shown) or the like.

[0021] Furthermore, a table base 18 is fixed to the upper surface side (front surface side) of the X-axis moving plate 10. On the upper surface of this table base 18, a columnar θ table 20 is provided.

[0022] Also, around the θ table 20, a cover 22 having a rectangular upper surface is provided. And, on the upper surface of the θ table 20, a disk-shaped chuck table 24 having a holding surface for holding the wafer at the upper part is fixed.

[0023] Also, the θ table 20 is connected to a rotational drive source (not shown) such as a motor for rotating the θ table 20 and the chuck table 24. The rotation axis when the θ table 20 and the chuck table 24 rotate is parallel to the Z-axis direction and passes through the center of the holding surface of the chuck table 24.

[0024] This chuck table 24 has a disk-shaped frame body 26 formed of a metal such as stainless steel. Also, a disk-shaped recess is formed on the upper surface side of the frame body 26. And, in this recess, a disk-shaped porous plate 28 formed of porous ceramics and having an outer diameter approximately the same as the inner diameter of the recess is fixed.

[0025] This porous plate 28 is connected to a suction source (not shown), such as a vacuum pump, via a flow path formed in the frame 26. When the suction source is operated, negative pressure is generated in the space near the upper surface of the porous plate 28 (the holding surface of the chuck table 24).

[0026] Therefore, by operating the suction source while the wafer is placed on the holding surface of the chuck table 24, it is possible to suction and hold the wafer on the holding surface of the chuck table 24.

[0027] Figure 2(A) is a schematic top view showing an example of a wafer held on the holding surface of the chuck table 24, and Figure 2(B) is a schematic cross-sectional view showing a cross-section of the wafer shown in Figure 2(A).

[0028] The wafer 11 shown in Figures 2(A) and 2(B) is made of a single-crystal semiconductor material such as Si (silicon), SiC (silicon carbide), or GaN (gallium nitride). On the surface 11a side of the wafer 11, there is a device region 13a and an outer peripheral excess region 13b surrounding the device region 13a.

[0029] The device region 13a is then divided into multiple regions by multiple division lines arranged in a grid pattern. A device 15, such as an IC or LSI, is formed in each of these regions. The outer edge of the wafer 11 is also chamfered; that is, the side surface 11b of the wafer 11 is curved so as to be convex outwards.

[0030] Furthermore, a notch 11c is formed on the outer edge of the wafer 11, indicating a specific crystal orientation of the material constituting the wafer 11. When the edge trimming of the wafer 11 is performed, the back surface 11d of the wafer 11 is placed on the holding surface of the chuck table 24 (the upper surface of the porous plate 28), either directly or via a dicing tape.

[0031] In the cutting apparatus 2 shown in Figure 1, the movement of the table base 18 along the X-axis direction is controlled by the X-axis movement mechanism 6. The chuck table 24 is supported by the table base 18 via the θ-table 20. Therefore, the chuck table 24 moves along the X-axis direction together with the table base 18.

[0032] A gate-shaped support structure 30 is provided on the base 4, positioned to straddle the X-axis movement mechanism 6. A pair of ball-screw type Y-axis movement mechanisms 32a and 32b are provided on the front (surface) of this support structure 30. Each of these Y-axis movement mechanisms 32a and 32b has the same components as the X-axis movement mechanism 6 described above.

[0033] The Y-axis movement mechanism 32a moves the Y-axis movement plate 34a along the Y-axis direction within a range where it does not contact the Y-axis movement plate 34b. Similarly, the Y-axis movement mechanism 32b moves the Y-axis movement plate 34b along the Y-axis direction within a range where it does not contact the Y-axis movement plate 34a.

[0034] Furthermore, ball screw type Z-axis movement mechanisms 36a and 36b are provided on the front (surface) of the pair of Y-axis movement plates 34a and 34b, respectively. Each of these Z-axis movement mechanisms 36a and 36b has the same components as the X-axis movement mechanism 6 described above.

[0035] Then, the Z-axis movement mechanism 36a moves the Z-axis movement plate 38a along the Z-axis direction. Similarly, the Z-axis movement mechanism 36b moves the Z-axis movement plate 38b along the Z-axis direction.

[0036] A pair of cylindrical housings 40a and 40b, each having opposing sides and extending along the Y-axis direction, are fixed to the lower part of the Z-axis moving plates 38a and 38b. Inside each housing 40a and 40b are cutting units 42a and 42b.

[0037] However, some components of the cutting unit 42a are exposed from the side of the housing 40a facing the housing 40b. Similarly, some components of the cutting unit 42b are exposed from the side of the housing 40b facing the housing 40a.

[0038] Note that the components of cutting unit 42a and cutting unit 42b are the same. Therefore, the components of cutting unit 42b will be described below with reference to Figure 3. Figure 3 is an exploded perspective view schematically showing the components of cutting unit 42b that are exposed and not housed in housing 40b.

[0039] The cutting unit 42b has a spindle 44 with one end protruding from the housing 40b. The spindle 44 is supported in the housing 40b in such a manner that it can rotate about a straight line parallel to the Y-axis as the axis of rotation.

[0040] Furthermore, the other end of the spindle 44 is connected to a rotational drive source (not shown), such as a motor, for rotating the spindle 44. This rotational drive source is housed in the housing 40b.

[0041] Furthermore, a mount 48 is attached to one end of the spindle 44, and a circular cutting blade 46 is mounted on it. An opening 44a is also formed at one end of the spindle 44. In addition, screw grooves are formed on the inner wall surface 44b of the spindle 44.

[0042] The mounter 48 has a disc-shaped flange portion 50 and a boss portion 52 that protrudes from the surface of the flange portion 50. An opening 50a is formed in the center of the flange portion 50, passing through it. A fitting portion (not shown) is provided on the back side of the flange portion 50 into which the tip of the spindle 44 can be fitted.

[0043] Then, with one end of the spindle 44 fitted into this fitting portion, the mounter fixing bolt 54 is tightened into the openings 50a and 44a to fix the mounter 48 to the spindle 44. The outer wall surface 54a of the mounter fixing bolt 54 is provided with threads corresponding to the thread grooves formed on the inner wall surface 44b of the spindle 44.

[0044] Furthermore, the surface of the flange portion 50 becomes a contact surface 50b that comes into contact with the back surface of the cutting blade 46. This contact surface 50b is formed in an annular shape when viewed from the direction in which the spindle 44 extends (Y-axis direction). The boss portion 52 is formed in a cylindrical shape, and its outer wall surface 52a is provided with screw threads.

[0045] Furthermore, an opening 46a is formed in the center of the cutting blade 46 through which the boss portion 52 is inserted. The cutting blade 46 is then mounted to the mount 48 by inserting the boss portion 52 through the opening 46a.

[0046] Furthermore, with the cutting blade 46 mounted on the mounter 48, an annular flange 56 is attached to the surface side of the cutting blade 46. An opening 56a is formed in the center of this flange 56, and the boss portion 52 of the mounter 48 is fitted into this opening 56a.

[0047] Furthermore, the back surface of the flange 56 becomes a contact surface (not shown) that comes into contact with the surface of the cutting blade 46. This contact surface is provided in an annular shape to correspond to the contact surface 50b of the mounter 48.

[0048] After attaching the flange 56 to the surface side of the cutting blade 46, an annular flange fixing nut 58 is tightened onto the tip of the boss portion 52. This presses the flange 56 toward the mount 48, and the cutting blade 46 is clamped between the mount 48 and the flange 56.

[0049] In other words, the surface of the cutting blade 46 contacts the contact surface of the flange 56, and the back surface of the cutting blade 46 contacts the contact surface 50b of the mounter 48, thereby holding the cutting blade 46 in a predetermined position.

[0050] Furthermore, the flange fixing nut 58 has an opening 58a. In addition, the inner wall surface 58b of the flange fixing nut 58 has a screw groove formed therein that corresponds to the screw threads provided on the outer wall surface 52a of the boss portion 52.

[0051] Furthermore, as shown in Figure 1, liquid supply units 60a and 60b are provided around the components of the cutting units 42a and 42b that are exposed and not housed in the housings 40a and 40b. The components of liquid supply unit 60a and liquid supply unit 60b are the same.

[0052] Therefore, the components of the liquid supply unit 60b will be described below with reference to Figure 4. Figure 4 is a schematic side view showing the components of the liquid supply unit 60b. Note that in Figure 4, some of the components of the liquid supply unit 60b are shown in a simplified manner.

[0053] The liquid supply unit 60b has a blade cover 62 that surrounds the outer circumference of the cutting blade 46, excluding the area near the lower end (B). Inside this blade cover 62, a pair of L-shaped nozzles 64 are fixed, sandwiching the lower part of the cutting blade 46.

[0054] Each of the pair of nozzles 64 is connected to a liquid supply source 72 via a connecting portion 66 provided on the blade cover 62, a pipe 68 connected to the connecting portion 66, and a valve 70 connected to the pipe 68.

[0055] Furthermore, each tip of the pair of nozzles 64 has multiple slits (not shown) that face the cutting blade 46. When the valve 70 is open, the liquid supplied from the liquid supply source 72 is supplied through the piping 68 and connecting part 66 to the vicinity of the lower end (B) of the cutting blade 46 via the multiple slits.

[0056] Furthermore, a nozzle 74 is also provided in front of the cutting blade 46. This nozzle 74 is spaced apart from the cutting blade 46 when viewed from the Y-axis direction, and overlaps with the cutting blade 46 when viewed from the X-axis direction. The nozzle 74 also has an upper part 74a that extends along the Z-axis direction, and a lower part 74b that is bent from the lower end of the upper part 74a toward the cutting blade 46 and extends linearly diagonally downward.

[0057] The nozzle 74 is connected to the liquid supply source 72 via a connecting portion 76 provided on the blade cover 62, a pipe 78 connected to the connecting portion 76, and a valve 80 connected to the pipe 78.

[0058] An opening 74c is formed at the tip of the nozzle 74 (the lower end of the lower part 74b). The tip of the nozzle 74 is also directed towards the area of ​​the wafer 11 located below the front end (F) of the cutting blade 46 when the wafer 11 is cut by the cutting blade 46.

[0059] Then, when the valve 80 is opened while the cutting blade 46 is cutting the wafer 11, the liquid supplied from the liquid supply source 72 is supplied via the piping 78 and the connecting part 76 to the area of ​​the wafer 11 located below the front end (F) of the cutting blade 46 from the tip of the nozzle 74.

[0060] Furthermore, a nozzle 82 is provided above the cutting blade 46. This nozzle 82 is positioned directly above the upper end (T) of the cutting blade 46 and extends along the Z-axis. The nozzle 82 is connected to the liquid supply source 72 via a connecting portion 84 provided on the blade cover 62, a pipe 86 connected to the connecting portion 84, and a valve 88 connected to the pipe 86.

[0061] An opening 82a is formed at the tip of the nozzle 82. The tip of the nozzle 82 is also pointed towards the upper end (T) of the cutting blade 46. When the valve 88 is open, the liquid supplied from the liquid supply source 72 is supplied from the tip of the nozzle 82 to the upper end (T) of the cutting blade 46 via the piping 86 and the connecting part 84.

[0062] Furthermore, as shown in Figure 1, imaging units 90a and 90b are fixed to the front surfaces of housings 40a and 40b, respectively. Each imaging unit 90a and 90b, for example, images the wafer 11 held on the holding surface of the chuck table 24.

[0063] Each imaging unit 90a, 90b includes, for example, a light source such as an LED (Light Emitting Diode), an objective lens, and an image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0064] Figure 5 is a schematic flowchart illustrating an example of a wafer processing method for performing edge trimming of the wafer 11 in the cutting apparatus 2. In this method, first, the wafer 11 is held in a state where it can rotate along the circumferential direction and its surface 11a is facing upward (holding step: S1).

[0065] Specifically, the X-axis movement mechanism 6 is operated so that the chuck table 24 is positioned in front of the base 4, and then the wafer 11 is placed on the chuck table 24 so that the center of the holding surface of the chuck table 24 and the center of the back surface 11d of the wafer 11 overlap. Then, the suction source connected to the porous plate 28 of the chuck table 24 is operated so that the wafer 11 is held by the chuck table 24.

[0066] Next, the wafer 11 is edge-trimmed while a cleaning solution is supplied to the center of the surface 11a of the wafer 11 and the wafer 11 is rotated, thereby forming a film of cleaning solution that covers the surface 11a of the wafer 11 (processing step: S2). Figures 6(A), 6(B), and 6(C) are schematic partial cross-sectional front views showing the processing step (S2).

[0067] In this processing step (S2), first, the X-axis movement mechanism 6 and the Y-axis movement mechanisms 32a and 32b are operated so that the liquid supply unit 60a is positioned above the center of the surface 11a of the wafer 11, and the cutting blade 46 of the cutting unit 42b is positioned above the outer edge of the wafer 11 (see Figure 6(A)).

[0068] Next, valves 70, 80, and 88 are opened so that liquid (cutting fluid) L1 is supplied from nozzles 64, 74, and 82 of the liquid supply unit 60b, and the rotary drive source housed in the housing 40b is operated to rotate the cutting blade 46 of the cutting unit 42b. Then, the Z-axis movement mechanism 36b is operated so that the lower end of the cutting blade 46 of the cutting unit 42b cuts into the outer edge of the wafer 11 (see Figure 6(B)).

[0069] Next, with cutting fluid L1 supplied from nozzles 64, 74, and 82 of the liquid supply unit 60b, and the cutting blade 46 of the cutting unit 42b rotating, the valve 80 is opened so that liquid (cleaning fluid) L2 is supplied from nozzle 74 of the liquid supply unit 60a to the center of the surface 11a of the wafer 11, and the rotation drive source connected to the θ table 20 is operated so that the wafer 11 held in the chuck table 24 rotates along the circumferential direction of the wafer 11 (see Figure 6(C)).

[0070] The flow rate of the cleaning solution L2 at this time is, for example, 1.0 l / min to 0.1 l / min. Furthermore, the flow rate of the cleaning solution L2 is preferably 0.5 l / min to 0.1 l / min, and more preferably 0.3 l / min to 0.1 l / min. Also, the rotation speed of the chuck table 24 (wafer 11) at this time is, for example, 90 deg / sec to 120 deg / sec.

[0071] By performing the processing step (S2) described above, a portion of the surface 11a side of the outer edge of the wafer 11 is cut and removed. In other words, the wafer 11 is edge-trimmed. In this case, the cleaning solution L2 supplied to the center of the surface 11a of the wafer 11 spreads radially due to centrifugal force, forming a cleaning solution film LF that covers the entire surface 11a of the wafer 11.

[0072] Therefore, in this processing step (S2), drying of the surface 11a of the wafer 11 can be prevented, reducing the likelihood of cutting debris entering the device 15. Furthermore, in this processing step (S2), the consumption of cleaning solution L2 can be reduced compared to the case where edge trimming of the wafer 11 is performed while supplying a curtain-like cleaning solution to the entire surface 11a of the wafer 11.

[0073] The method described above is one aspect of the present invention, and the present invention also includes aspects different from the method described above. For example, in the present invention, in order to reduce the burden of edge trimming, the edge trimming of the outer edge of the wafer 11 may be performed in stages.

[0074] In other words, in the processing step (S2) of the present invention, a cutting step that increases the depth from the surface 11a at the outer peripheral edge of the wafer 11 at the lower end of the rotating cutting blade 46 and a rotation step that rotates the wafer 11 at least once may be performed alternately and repeatedly.

[0075] Furthermore, in the present invention, an ultraviolet irradiation step may be performed before the processing step (S2) in which ultraviolet light is irradiated onto the surface 11a of the wafer 11. Figure 7 is a schematic front view showing the ultraviolet irradiation step. In this ultraviolet irradiation step, for example, ultraviolet UV light is irradiated onto the surface 11a of the wafer 11 from an ultraviolet lamp 92 in the atmosphere.

[0076] When ultraviolet (UV) light is irradiated in this way, reactive oxygen species are generated from oxygen present in the atmosphere. These reactive oxygen species then react with organic matter present on the surface 11a of the wafer 11 to form hydrophilic substituents. As a result, hydrophilicity is imparted to the surface 11a of the wafer 11. In this case, the surface 11a of the wafer 11 becomes more easily wettable, further reducing the consumption of cleaning solution L2.

[0077] Furthermore, the structures and methods of the embodiments described above can be modified as appropriate without departing from the scope of the present invention. [Examples]

[0078] In each of Examples 1 to 3, the number of particles (cutting debris) adhering to the surface 11a after edge trimming of the wafer 11, while supplying cleaning solution L2 to the center of the surface 11a of the wafer 11, was evaluated.

[0079] In Example 1, the flow rate of the cleaning solution L2 was set to 0.2 l / min. In Example 2, the flow rate of the cleaning solution L2 was set to 0.4 l / min. In Example 3, the flow rate of the cleaning solution L2 was set to 0.2 l / min, and ultraviolet light was irradiated onto the surface 11a of the wafer 11 before edge trimming.

[0080] Furthermore, in Comparative Example 1, the number of particles adhering to the surface 11a of the wafer 11 after edge trimming was performed while supplying cleaning solution in a curtain-like manner over the entire surface 11a of the wafer 11 was evaluated. In Comparative Example 1, the flow rate of the cleaning solution supplied in a curtain-like manner was set to 2.5 l / min.

[0081] In addition, in Comparative Example 2, the number of particles adhering to the surface 11a after edge trimming of the wafer 11, without supplying cleaning solution L2 to the center of the surface 11a of the wafer 11, was evaluated.

[0082] Table 1 shows the number of particles attached to the surface 11a of each wafer 11 after edge trimming for Examples 1-3 and Comparative Examples 1 and 2. [Table 1]

[0083] As shown in Table 1, it was found that when edge trimming of the wafer 11 is performed while supplying cleaning solution L2 to the center of the surface 11a of the wafer 11, the number of particles adhering to the surface 11a can be reduced (see Examples 1-3 and Comparative Example 2).

[0084] Furthermore, in this case, it was found that the amount of cleaning solution L2 required to reduce the number of particles adhering to the surface 11a can be significantly reduced compared to the case where the cleaning solution is supplied in a curtain-like manner over the entire surface 11a of the wafer 11 (see Examples 1 and 2 and Comparative Example 1).

[0085] Furthermore, it was found that if the surface 11a of the wafer 11 is irradiated with ultraviolet light before edge trimming of the wafer 11 to impart hydrophilicity to the surface 11a of the wafer 11, the amount of cleaning solution L2 required to reduce the number of particles adhering to the surface 11a can be further reduced (see Examples 1-3). [Explanation of symbols]

[0086] 2:Cutting device 4: Base 6:X-axis movement mechanism 8: Guide rail 10: X-axis movement plate 11: Wafer (11a: Front, 11b: Side, 11c: Notch, 11d: Back) 12: Screw shaft 13a: Device area 13b: Peripheral surplus region 14: Motor 15: Device 16: Water Case 18: Table base 20: θ table 22: Cover 24: Chuck Table 26:Frame body 28: Porous board 30:Support structure 32a, 32b: Y-axis movement mechanism 34a, 34b: Y-axis moving plate 36a, 36b: Z-axis movement mechanism 38a, 38b: Z-axis movement plate 40a, 40b: Housing 42a, 42b: Cutting unit 44: Spindle (44a: Opening, 44b: Inner wall surface) 46: Cutting blade (46a: Opening) 48: Mounter 50: Flange section (50a: Opening, 50b: Contact surface) 52: Boss section (52a: Exterior wall surface) 54: Mount fixing bolt (54a: Exterior wall surface) 56: Flange (56a: Opening) 58: Flange fixing nut (58a: opening, 58b: inner wall surface) 60a, 60b: Liquid supply unit 62: Blade Cover 64: Nozzle 66:Connection part 68: Piping 70: Valve 72 :Liquid supply source 74: Nozzle (74a: Top, 74b: Bottom, 74c: Opening) 76:Connection part 78: Piping 80: Valve 82: Nozzle (82a: Opening) 84:Connection part 86: Piping 88: Valve 90a, 90b: Imaging unit 92: UV lamp

Claims

1. A method for processing a wafer in which multiple devices are formed on the surface and the outer edge is chamfered, A holding step in which the wafer is rotatable along the circumferential direction of the wafer and is held by suction on the upper surface of a porous plate with its surface facing upward, After the holding step, a processing step is performed in which, with the lower end of the first cutting blade rotating while supplying cutting fluid from a first liquid supply unit provided around the annular first cutting blade and cutting into the outer edge of the wafer, a cleaning fluid is supplied to the center of the surface of the wafer from a second liquid supply unit provided around an annular second cutting blade, which is provided separately from the first cutting blade, and the wafer is rotated to form a film of the cleaning fluid that covers the surface of the wafer, thereby processing the outer edge of the wafer. A wafer processing method comprising [a specific feature].

2. The wafer processing method according to claim 1, further comprising an ultraviolet irradiation step of irradiating the surface of the wafer with ultraviolet light to impart hydrophilicity before the processing step.

3. In the processing step, A cutting step that increases the depth from the surface of the lower end of the rotating cutting blade at the outer edge of the wafer, A rotation step of rotating the wafer at least once, A wafer processing method according to claim 1 or 2, wherein the process is performed alternately and repeatedly.

Images