Wafer processing method and cutting device

Abstract

To suppress the deterioration of processing quality.SOLUTION: A wafer processing method is a wafer processing method in which a wafer 200 is cut in a ring shape along the outer periphery of the wafer 200 with a cutting blade 21, and the wafer 200 is cut in a ring shape along the outer periphery of the wafer 200 with the cutting blade 21 while supplying cutting fluid 26 to the wafer 200, and the position of the cutting blade 21 is changed in the radial direction of the wafer 200 to cut the wafer 200, and the amount of cutting fluid 26 supplied while the cutting blade 21 cuts a position overlapping the outer peripheral edge 206 of the wafer 200 is set to be less than the amount of cutting fluid 26 supplied while the cutting blade 21 cuts a position not overlapping the outer peripheral edge 206 of the wafer 200.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a wafer processing method and cutting device for cutting a wafer into an annular shape along the outer periphery of the wafer with a cutting blade. [Background technology]

[0002] When a wafer is subjected to so-called edge trimming, a cutting fluid is supplied to the wafer to prevent adhesion of cutting debris to the wafer and to cool the wafer down to cool the heat generated by cutting (see, for example, Patent Document 1).

[0003] In the conventional processing method shown in Patent Document 1 and the like, when it is desired to remove an annular region of a predetermined width extending from the outer edge of the wafer toward the center of the wafer, the position of the cutting blade is changed in the radial direction of the wafer to perform circular cutting multiple times, or the cutting blade is used to perform spiral cutting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-225612 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional processing method shown in Patent Document 1 and the like, when the cutting blade cuts the outermost periphery of the wafer, the cutting fluid is likely to get onto the underside of the wafer, and if the cutting fluid gets onto the underside of the wafer, there is a risk that the wafer will flap during cutting, resulting in a deterioration in processing quality, so improvements are urgently needed.

[0006] An object of the present invention is to provide a wafer processing method and cutting device that can suppress deterioration of processing quality. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the wafer processing method of the present invention is a wafer processing method in which a cutting blade cuts a wafer in a ring shape along the outer periphery of the wafer, and is characterized in that cutting fluid is supplied to the wafer while the cutting blade cuts the wafer in a ring shape along the outer periphery of the wafer and the position of the cutting blade is changed in the radial direction of the wafer to cut the wafer, and the amount of cutting fluid supplied while the cutting blade cuts a position that overlaps the outer edge of the wafer is set to be less than the amount of cutting fluid supplied while the cutting blade cuts a position that does not overlap the outer edge of the wafer.

[0008] In the wafer processing method, the cutting fluid is supplied to the wafer through the cutting blade by being sprayed toward the cutting blade from a pair of nozzles arranged on both sides of the cutting blade in the thickness direction, and while the cutting blade is cutting a position that overlaps the outer edge of the wafer, the cutting fluid is sprayed only from the nozzle of the pair that is closer to the center of the wafer, and while the cutting blade is cutting a position that does not overlap the outer edge of the wafer, the cutting fluid may be sprayed from both of the pair of nozzles.

[0009] In the wafer processing method, the wafer may have a first surface and a second surface behind the first surface, and a chamfered portion may be formed on the outer periphery so that the diameters of the first surface and the second surface are set smaller than the maximum outer diameter of the wafer, and the wafer may be cut by the cutting blade while the first surface side or the second surface side is adsorbed on an adsorption table having an adsorption area corresponding to the first surface or the second surface.

[0010] The cutting device of the present invention comprises a holding table for holding a wafer, a cutting blade for cutting the wafer in a circular shape along the outer periphery of the wafer held by the holding table, and a cutting fluid supply nozzle for supplying cutting fluid to the wafer being cut by the cutting blade, and is characterized in that the cutting fluid is supplied to the wafer from the cutting fluid supply nozzle while the cutting blade cuts the wafer held by the holding table in a circular shape along the outer periphery of the wafer, and the position of the cutting blade is changed in the radial direction of the wafer to cut the wafer, and the amount of cutting fluid supplied while the cutting blade cuts a position overlapping the outer edge of the wafer is set to be less than the amount of cutting fluid supplied while the cutting blade cuts a position not overlapping the outer edge of the wafer.

[0011] In the cutting device, the cutting fluid supply nozzle may include a first nozzle and a second nozzle arranged on both sides of the cutting blade in the thickness direction, and while the cutting blade is cutting a position that overlaps the outer edge of the wafer, the cutting fluid may be supplied only from the nozzle of the first nozzle and the second nozzle that is closer to the center of the wafer, and while the cutting blade is cutting a position that does not overlap the outer edge of the wafer, the cutting fluid may be supplied from both the first nozzle and the second nozzle.

[0012] In the cutting device, the wafer has a first surface and a second surface behind the first surface, and a chamfered portion is formed on the outer periphery so that the diameters of the first surface and the second surface are set smaller than the outer diameter of the wafer, and the holding table may have an adsorption area corresponding to the first surface or the second surface of the wafer. [Effects of the Invention]

[0013] The present invention has an effect of suppressing deterioration of processing quality. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a cutting device according to the first embodiment. [Figure 2]FIG. 2 is a perspective view schematically showing a wafer to be processed by the cutting device shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 4 is a side view of the cutting unit of the cutting device shown in FIG. 1. FIG. [Figure 5] FIG. 5 is a front view schematically showing a main part of the cutting unit shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a state in which the holding table holds the wafer by suction in the wafer processing method according to the first embodiment. [Figure 7] FIG. 7 is a plan view schematically showing a state in which the outer periphery of the wafer held on the holding table is positioned at a position away from the cutting unit in the X-axis direction in the wafer processing method according to the first embodiment. [Figure 8] FIG. 8 is a plan view schematically showing a state in which the holding table shown in FIG. 7 is brought close to the cutting unit to cause the cutting blade to cut into the outer peripheral edge of the wafer in the wafer processing method according to the first embodiment. [Figure 9] FIG. 9 is a front view, partially in section, schematically showing the main part of the cutting unit shown in FIG. [Figure 10] FIG. 10 is a front view, partially in cross section, schematically showing a modification of the main part of the cutting unit shown in FIG. [Figure 11] FIG. 11 is a plan view schematically showing a state in which the holding table shown in FIG. 8 is positioned at a position away in the X-axis direction from the cutting unit that has been moved in the Y-axis direction in the wafer processing method according to the first embodiment. [Figure 12] FIG. 12 is a plan view schematically showing a state in which the cutting blade shown in FIG. 11 is caused to cut into the wafer from its outer periphery toward the inner periphery. [Figure 13] 13 is a schematic front view, partially in cross section, of the main part of the cutting unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0016] [Embodiment 1] A cutting device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of the configuration of the cutting device according to the first embodiment. FIG. 2 is a perspective view schematically showing a wafer to be processed by the cutting device shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a side view of a cutting unit of the cutting device shown in FIG. 1. FIG. 5 is a front view schematically showing a main part of the cutting unit shown in FIG. 4.

[0017] (wafer) The cutting device 1 according to the first embodiment is a processing device that cuts a wafer 200 shown in Fig. 2. In the first embodiment, the wafer 200 is a semiconductor wafer, an optical device wafer, or the like, whose base material is silicon, sapphire, gallium nitride, gallium arsenide, or the like. As shown in Fig. 2, the wafer 200 is formed in a disk shape having a circular front surface 201 (corresponding to a first surface) and a circular back surface 202 (second surface) that is the back surface of the front surface 201 and is parallel to the front surface 201.

[0018] The wafer 200 has devices 204 formed in regions partitioned in a grid pattern by a plurality of planned division lines 203 formed in a grid pattern on a surface 201. The devices 204 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), or memories (semiconductor storage devices).

[0019] 3, the wafer 200 has a chamfered portion 205 formed on its outer periphery. The chamfered portion 205 is formed from the front surface 201 to the back surface 202, and is formed to have an arc-shaped cross section such that the center in the thickness direction is located on the outermost side. The outer surface of the chamfered portion 205 is the outer peripheral edge 206 of the wafer 200. With the chamfered portion 205 formed, the diameters of the front surface 201 and the back surface 202 of the wafer 200 are set smaller than the maximum outer diameter of the wafer 200 (the diameter at the center in the thickness direction).

[0020] The wafer 200 has its outer peripheral edge 206 removed from the front surface 201 side all around the circumference to a depth 207 exceeding a predetermined thickness, and then the back surface 202 side is ground or otherwise thinned to a predetermined thickness. The wafer 200 is then divided into individual devices 204 along planned division lines 203. Note that in the first embodiment, the depth 207 is a depth that extends from the front surface 201 beyond the center in the thickness direction and reaches a position closer to the back surface 202 than the center in the thickness direction.

[0021] (cutting equipment) 1 is a processing device that holds a wafer 200 on a holding table 10 and cuts an outer peripheral edge 206 of the wafer 200 with a cutting blade 21 to form an annular groove 210 (shown in FIG. 13) having a depth 207 exceeding a predetermined thickness and a predetermined width along the entire circumference of the outer peripheral portion, including the outer peripheral edge 206, from the surface 201 side of the wafer 200. As shown in FIG. 1, the cutting device 1 includes a holding table 10 (corresponding to a suction table) that holds the wafer 200 by suction on a holding surface 11, a cutting unit 20 that cuts the wafer 200 held by the holding table 10 with the cutting blade 21, an imaging unit 30 that takes an image of the wafer 200 held on the holding table 10, and a control unit 100.

[0022] 1, the cutting device 1 also includes a moving unit 40 that moves the cutting unit 20 relative to the wafer 200 held by the holding table 10. The moving unit 40 includes an X-axis moving unit 41 that moves the holding table 10 for processing in the X-axis direction parallel to the horizontal direction, a Y-axis moving unit 42 that indexes and moves the cutting unit 20 in the Y-axis direction that is parallel to the horizontal direction and perpendicular to the X-axis direction, a Z-axis moving unit 43 that moves the cutting unit 20 for cutting in the Z-axis direction that is parallel to the vertical direction and perpendicular to both the X-axis and Y-axis directions, and a rotary moving unit 44 that rotates the holding table 10 around an axis parallel to the Z-axis direction.

[0023] The X-axis movement unit 41 moves the holding table 10 in the X-axis direction, which is the processing feed direction, to perform processing feed between the holding table 10 and the cutting unit 20 relative to each other along the X-axis. The Y-axis movement unit 42 moves the cutting unit 20 in the Y-axis direction, which is the indexing feed direction, to perform index feed between the holding table 10 and the cutting unit 20 relative to each other along the Y-axis. The Z-axis movement unit 43 moves the cutting unit 20 in the Z-axis direction, which is the cutting feed direction, to perform cutting feed between the holding table 10 and the cutting unit 20 relative to each other along the Z-axis.

[0024] The X-axis moving unit 41, the Y-axis moving unit 42, and the Z-axis moving unit 43 are equipped with a well-known ball screw that is rotatable around its axis, a well-known motor that rotates the ball screw around its axis, and a well-known guide rail that supports the holding table 10 or the cutting unit 20 so that it can move freely in the X-axis, Y-axis, or Z-axis direction.

[0025] The holding table 10 is disk-shaped, and has a holding surface 11 (corresponding to an adsorption area) that holds the wafer 200, which is formed from porous ceramic or the like. That is, the holding table 10 has the holding surface 11. The outer diameter of the holding surface 11 is equal to (in the first embodiment, equal to) the outer diameters of the front surface 201 and the back surface 202 of the wafer 200. The holding table 10 is provided so as to be movable in the X-axis direction by an X-axis moving unit 41 across a processing area below the cutting unit 20 and a carry-in / out area that is spaced from below the cutting unit 20 and through which the wafer 200 is carried in and out, and is provided so as to be rotatable about an axis parallel to the Z-axis direction by a rotary moving unit 44.

[0026] The holding table 10 has a holding surface 11 connected to a suction source 13 via an on-off valve 12, and when the on-off valve 12 is opened, the suction source 13 sucks and holds (also referred to as adsorbs) the wafer 200 placed on the holding surface 11. In the first embodiment, the holding table 10 sucks and holds the back surface 202 side of the wafer 200. In this manner, the holding surface 11 suction-holds the wafer 200. The outer diameter of the holding surface 11 that adsorbs the wafer 200 is equal to the outer diameters of the front surface 201 and the back surface 202 of the holding table 10, so that the size of the holding surface 11 corresponds to the front surface 201 or the back surface 202 of the wafer 200.

[0027] The cutting unit 20 is a cutting means having a spindle 23 to which a cutting blade 21 for cutting the wafer 200 held by the holding table 10 is detachably fixed. The cutting unit 20 is provided so as to be movable in the Y-axis direction by a Y-axis moving unit 42 relative to the wafer 200 held on the holding table 10, and is also provided so as to be movable in the Z-axis direction by a Z-axis moving unit 43.

[0028] The cutting unit 20 is mounted on a gate-shaped support frame 3 that stands upright from the device main body 2 via a Y-axis moving unit 42, a Z-axis moving unit 43, etc. The cutting unit 20 is capable of positioning the cutting blade 21 at any position on the holding surface 11 of the holding table 10 by the Y-axis moving unit 42 and the Z-axis moving unit 43.

[0029] The cutting unit 20 comprises a cutting blade 21, a spindle housing 22 movable in the Y-axis direction and the Z-axis direction by a Y-axis moving unit 42 and a Z-axis moving unit 43, a spindle 23 rotatably mounted on the spindle housing 22 around its axis, a spindle motor (not shown) that rotates the spindle 23 around its axis, a blade cover 24 (shown in Figure 4) attached to the tip surface of the spindle housing 22 and covering at least the upper part of the cutting blade 21, and a cutting fluid supply nozzle 25 mounted on the blade cover 24 and supplying cutting fluid 26 (shown in Figure 9, etc.) to the cutting blade 21, etc.

[0030] The cutting blade 21 is an extremely thin cutting grindstone having a substantially ring shape, and cuts the wafer 200 in an annular shape along the outer periphery of the wafer 200 held by the holding table 10. In the first embodiment, as shown in Fig. 4, the cutting blade 21 includes an annular cutting blade 211 that cuts the wafer 200, and an annular base 212 that supports the cutting blade 211 on its outer edge and is detachably attached to the spindle 23.

[0031] The cutting blade 211 is made of abrasive grains such as diamond or CBN (Cubic Boron Nitride) and a bonding material such as metal or resin, and is formed to a predetermined thickness. In the present invention, the cutting blade 21 may be a so-called washer blade consisting only of the cutting blade 211. In the first embodiment, the cutting edge of the cutting blade 211 is formed flat along the Y-axis direction, as shown in FIG.

[0032] The spindle housing 22 is supported by a Z-axis moving unit 43 so as to be movable in the Z-axis direction, and is supported by a Y-axis moving unit 42 via the Z-axis moving unit 43 so as to be movable in the Y-axis direction. The spindle housing 22 accommodates a portion of the spindle 23 excluding the tip end thereof, a spindle motor (not shown), and the like, and supports the spindle 23 so as to be rotatable about its axis.

[0033] The cutting blade 21 is fixed to the tip of the spindle 23. The spindle 23 is rotated by a spindle motor (not shown), and its tip protrudes from the tip surface of the spindle housing 22. The tip of the spindle 23 is gradually tapered toward the tip, and the cutting blade 21 is fixed to it.

[0034] The blade cover 24 includes a fixed-side cover 241 fixed to the tip surface of the spindle housing 22, and a sliding-side cover 242 slidably mounted on the fixed-side cover 241 in the X-axis direction by a cylinder (not shown) mounted inside the fixed-side cover 241. When the cutting unit 20 cuts the wafer 200, the sliding-side cover 242 is positioned at a proximity position close to the fixed-side cover 241, as shown by the dashed line in Fig. 4, and when the cutting blade 21 is attached to or detached from the tip of the spindle 23, the sliding-side cover 242 is positioned at an attachment / detachment position farther away from the fixed-side cover 241 than the proximity position.

[0035] The cutting fluid supply nozzle 25 is provided on the blade cover 24 and supplies cutting fluid 26 (pure water in the first embodiment) to the cutting blade 21 and the like during cutting. As shown in Fig. 4, the cutting fluid supply nozzle 25 includes a spray nozzle 251, a shower nozzle 252, and a pair of blade coolers 253 (corresponding to a pair of nozzles).

[0036] The spray nozzle 251 is provided on the fixed side cover 241 of the blade cover 24, and is provided furthest forward in the processing feed direction (the relative movement direction of the cutting blade 21 relative to the wafer 200 along the X-axis direction when the cutting blade 21 cuts the wafer 200) among the spray nozzle 251, shower nozzle 252, and blade cooler 253. The spray nozzle 251 sprays the cutting fluid 26 downward from the fixed side cover 241 of the blade cover 24, thereby supplying the cutting fluid 26 to the wafer 200 during cutting processing.

[0037] The shower nozzle 252 is provided on the fixed-side cover 241 of the blade cover 24, and faces the cutting edge of the cutting blade 211 of the cutting blade 21 in the X-axis direction. The shower nozzle 252 sprays cutting fluid 26 from the fixed-side cover 241 along the X-axis direction onto the cutting edge of the cutting blade 211 of the cutting blade 21, thereby supplying cutting fluid 26 to the cutting blade 21 during cutting.

[0038] The pair of blade coolers 253 are provided on the sliding side cover 242 of the blade cover 24, each extending parallel to the X-axis direction and spaced apart from each other in the Y-axis direction. As shown in Fig. 5, the pair of blade coolers 253 are disposed on both sides of the cutting edge 211 of the cutting blade 21 in the thickness direction, with the lower end of the cutting edge 211 of the cutting blade 21 positioned between them.

[0039] The pair of blade coolers 253 are provided with cutting fluid jetting holes (not shown) that face the lower ends of the cutting edges 211 of the cutting blades 21. The blade coolers 253 jet cutting fluid 26 from the cutting fluid jetting holes along the Y-axis direction onto the lower ends of the cutting edges 211 of the cutting blades 21, thereby supplying the cutting fluid 26 to the cutting blades 21 during cutting.

[0040] In the first embodiment, the pair of blade coolers 253 are supplied with the cutting fluid 26 via respective on-off valves (not shown). The pair of blade coolers 253 can spray the cutting fluid 26 independently of each other by opening and closing the on-off valves. One of the pair of blade coolers 253 is a first nozzle, and the other is a second nozzle.

[0041] The axes of the spindle 23 and cutting blade 21 of the cutting unit 20 are set parallel to the Y-axis direction.

[0042] The imaging unit 30 is fixed to the cutting unit 20 so as to move integrally with the cutting unit 20. The imaging unit 30 is equipped with an imaging element that captures an image of the area to be divided of the wafer 200 held on the holding table 10 before cutting. The imaging element is, for example, a CCD (Charge-Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element. The imaging unit 30 captures an image of the wafer 200 held on the holding table 10 to obtain an image for performing alignment between the wafer 200 and the cutting blade 21, and outputs the obtained image to the control unit 100.

[0043] The cutting device 1 also includes an X-axis position detection unit (not shown) for detecting the position of the holding table 10 in the X-axis direction, a Y-axis position detection unit (not shown) for detecting the position of the cutting unit 20 in the Y-axis direction, and a Z-axis position detection unit for detecting the position of the cutting unit 20 in the Z-axis direction. The X-axis position detection unit and the Y-axis position detection unit may be configured with a linear scale parallel to the X-axis direction or the Y-axis direction and a read head. The Z-axis position detection unit detects the position of the cutting unit 20 in the Z-axis direction using motor pulses. The X-axis position detection unit, the Y-axis position detection unit, and the Z-axis position detection unit output the position of the holding table 10 in the X-axis direction and the position of the cutting unit 20 in the Y-axis direction or the Z-axis direction to the control unit 100. In the first embodiment, the positions of each component of the cutting device 1 in the X-axis direction, the Y-axis direction, and the Z-axis direction are determined based on a predetermined reference position (not shown). The reference position in the Z-axis direction is the position of the cutting unit 20 where the lower end of the cutting edge of the cutting blade 21 is located on the same plane as the holding surface 11.

[0044] The cutting device 1 also includes a cassette elevator 50 that places a cassette 51 containing wafers 200 before and after cutting and moves the cassette 51 in the Z-axis direction, and a transport unit (not shown) that transports the wafers 200 between the cassette 51 and the holding table 10.

[0045] The control unit 100 controls each component of the cutting device 1 to cause the cutting device 1 to perform processing operations on the wafer 200. The control unit 100 is a computer having an arithmetic processing device with a microprocessor such as a CPU (central processing unit), a storage device with memory such as a ROM (read only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing in accordance with a computer program stored in the storage device, and outputs control signals for controlling the cutting device 1 to each component of the cutting device 1 via the input / output interface device.

[0046] The control unit 100 is connected to a display unit such as a liquid crystal display device that displays the status and images of the machining operation, an input unit that the operator uses to register machining content information, and a notification unit. The input unit is composed of at least one of a touch panel provided on the display unit and an external input device such as a keyboard. The notification unit emits at least one of sound and light to notify the operator.

[0047] (Wafer processing method) Next, a wafer processing method according to the first embodiment will be described. FIG. 6 is a cross-sectional view schematically showing a state in which the holding table holds the wafer by suction in the wafer processing method according to the first embodiment. FIG. 7 is a plan view schematically showing a state in which the outer periphery of the wafer held on the holding table is positioned at a position away from the cutting unit in the X-axis direction in the wafer processing method according to the first embodiment. FIG. 8 is a plan view schematically showing a state in which the holding table shown in FIG. 7 is moved closer to the cutting unit to cause the cutting blade to cut into the outer periphery of the wafer in the wafer processing method according to the first embodiment. FIG. 9 is a front view, partially in cross section, schematically showing a main part of the cutting unit shown in FIG. 8. FIG. 10 is a front view, partially in cross section, schematically showing a modified main part of the cutting unit shown in FIG. 9. FIG. 11 is a plan view schematically showing a state in which the holding table shown in FIG. 8 is positioned at a position away from the cutting unit in the X-axis direction, which has been moved in the Y-axis direction, in the wafer processing method according to the first embodiment. Fig. 12 is a plan view schematically showing a state in which the cutting blade shown in Fig. 11 is caused to cut into the wafer from its outer edge toward the inner periphery in the wafer processing method according to embodiment 1. Fig. 13 is a front view schematically showing, in partial cross section, the main part of the cutting unit shown in Fig. 12.

[0048] The wafer processing method according to the first embodiment is a method in which the cutting device 1 cuts the wafer 200 into an annular shape along the outer periphery of the wafer 200 with the cutting blade 21 to form an annular groove 210 in the outer edge portion including the outer periphery 206. The wafer processing method according to the first embodiment is also a processing operation of the cutting device 1 configured as described above.

[0049] In the wafer processing method according to the first embodiment, processing conditions are registered in the control unit 100 by an operator or the like, and a cassette 51 containing wafers 200 before cutting is placed on the cassette elevator 50. The wafer processing method according to the first embodiment is started by the cutting device 1 when the control unit 100 of the cutting device 1 receives an instruction to start the processing operation from the operator.

[0050] In the wafer processing method according to the first embodiment, when the cutting device 1 starts the process, the control unit 100 controls the moving unit 40 to position the holding table 10 in the carry-in / out area, and controls the transport unit to remove the wafer 200 before cutting from the cassette 51 and place it on the holding surface 11 of the holding table 10. In the wafer processing method according to the first embodiment, as shown in Fig. 6, the control unit 100 opens the on-off valve 12 of the cutting device 1 to suction-hold the back surface 202 of the wafer 200 on the holding surface 11 of the holding table 10.

[0051] In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 rotates the spindle 23 around its axis at a rotation speed determined by the processing conditions, and supplies cutting fluid 26 from the cutting fluid supply nozzle 25 to the cutting blade 21, etc. In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 controls the moving unit 40 to move the holding table 10 toward the processing area, the imaging unit 30 photographs the wafer 200, and performs alignment based on the image photographed by the imaging unit 30.

[0052] In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 controls the moving unit 40, the cutting unit 20, etc., to separate the cutting edge 211 of the cutting blade 21 rotating about the axis of the cutting unit 20 from a part of the outer edge 206 of the wafer 200 held on the holding table 10 along the X-axis direction, as shown in Fig. 7. Also, in the wafer processing method according to the first embodiment, the control unit 100 controls the moving unit 40, the cutting unit 20, etc., to position the lower end of the cutting edge 211 of the cutting blade 21 rotating about the axis at a position where the distance from the surface 201 of the wafer 200 held on the holding table 10 is the depth 207 described above. Furthermore, in the wafer processing method according to embodiment 1, the control unit 100 of the cutting device 1 sprays cutting fluid 26 from only one of the pair of blade coolers 253 that is located on the center side of the wafer 200 held on the holding table 10, and stops spraying cutting fluid 26 from the other blade cooler 253 that is located on the outer periphery of the wafer 200.

[0053] In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 controls the moving unit 40 to move the holding table 10 in the X-axis direction toward the cutting unit 20, causing the cutting edge 211 of the cutting blade 21 to cut into the outer edge portion including the outer peripheral edge 206 of the wafer 200, as shown in Fig. 8, while rotating the holding table 10 about its axis. Note that in the first embodiment, when the cutting edge 211 of the cutting blade 21 is first caused to cut into the outer peripheral portion of the wafer 200, the cutting edge 211 of the cutting blade 21 is positioned so that the entire thickness of the cutting edge 211 of the cutting blade 21 overlaps the base material of the wafer 200 in the Z-axis direction and the end face 213 of the cutting edge 211 closer to the spindle housing 22, i.e., on the outer peripheral side of the wafer 200, overlaps with the outer peripheral edge 206 of the wafer 200 in the Z-axis direction, as shown in Fig. 9.

[0054] In the first embodiment, when the cutting edge 211 of the cutting blade 21 is first cut into the outer edge portion of the wafer 200, as shown in Fig. 9, the cutting fluid 26 is sprayed only from one of the pair of blade coolers 253 located closer to the center of the wafer 200 held on the holding table 10, and spraying of the cutting fluid 26 from the other blade cooler 253 located closer to the outer periphery of the wafer 200 is stopped. In the present invention, when the cutting edge 211 of the cutting blade 21 is cut into the outer edge portion including the outer periphery 206 of the wafer 200, the cutting edge 211 of the cutting blade 21 may be positioned such that a portion of the cutting edge 211 of the cutting blade 21 located closer to the center of the wafer 200 in the thickness direction overlaps with the base material of the wafer 200 in the Z-axis direction, and another portion of the cutting edge 211 located closer to the outer periphery of the wafer 200 in the thickness direction is located closer to the outer periphery of the wafer 200 than the outer periphery 206 of the wafer 200, as shown in Fig. 10.

[0055] In the wafer processing method according to the first embodiment, when the holding table 10 of the cutting device 1 rotates at least once around its axis, the control unit 100 controls the moving unit 40 to move the holding table 10 in the X-axis direction away from the cutting unit 20, as shown in Fig. 11. As a result, the chamfered portion 205 including the outer peripheral edge 206 is removed from the front surface 201 side to a depth 207, and an annular groove 210 is formed along the outer peripheral edge 206 of the wafer 200. Thus, in the wafer processing method of embodiment 1, as shown in Figure 9, while cutting the position where at least a portion of the cutting edge 211 of the cutting blade 21 overlaps the outer edge 206 of the wafer 200 in the Z-axis direction, the cutting device 1 sprays cutting fluid 26 only from one of the pair of blade coolers 253 that is closer to the center of the wafer 200, and cutting fluid 26 is supplied to the cutting blade 21 only from the one blade cooler 253 that is closer to the center of the wafer 200.

[0056] In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 controls the movement unit 40 to move the cutting unit 20, i.e., the cutting blade 211 of the cutting blade 21, toward the center of the wafer 200 only along the Y-axis direction by an amount corresponding to the thickness of the cutting edge 211 of the cutting blade 21. In the wafer processing method according to the first embodiment, the control unit 100 of the cutting device 1 sprays the cutting fluid 26 from only both blade coolers of the pair of blade coolers 253. In the wafer processing method according to the first embodiment, the control unit 100 controls the movement unit 40 to move the holding table 10 in the X-axis direction toward the cutting unit 20, so that the cutting edge 211 of the cutting blade 21 cuts into the inner periphery of the annular groove 210 of the wafer 200, as shown in FIG. 12 , and simultaneously rotates the holding table 10 about its axis.

[0057] In the wafer processing method according to the first embodiment, when the holding table 10 rotates at least once around its axis, the control unit 100 controls the moving unit 40 to move the holding table 10 in the X-axis direction away from the cutting unit 20. As a result, the width of the annular groove 210 formed in the outer edge of the wafer 200 is expanded by the thickness of the cutting edge 211 of the cutting blade 21. Thus, in the wafer processing method according to the first embodiment, as shown in FIG. 13 , while cutting a position where the cutting edge 211 of the cutting blade 21 does not entirely overlap the outer peripheral edge 206 of the wafer 200 in the Z-axis direction, i.e., a position inner than the outer peripheral edge 206, the cutting device 1 sprays the cutting fluid 26 from both of the pair of blade coolers 253, and the cutting fluid 26 is supplied to the cutting blade 21 from both of the pair of blade coolers 253.

[0058] In the wafer processing method according to the first embodiment, the cutting device 1 repeats the following operations: moving the holding table 10 along the X-axis direction to cause the cutting edge 211 of the cutting blade 21 to cut into the wafer 200 and rotate the wafer 200 around its axis at least once until the width of the annular groove 210 reaches a width determined by the processing conditions; and moving the holding table 10 in the X-axis direction away from the cutting blade 21, and then moving the cutting blade 21 only in the Y-axis direction. In this way, the outer edge of the wafer 200, including the outer periphery 206, is cut by the cutting blade 21 with the back surface 202 held by suction on the holding table 10, to form the annular groove 210.

[0059] Thus, in the wafer processing method according to embodiment 1, the cutting device 1 cuts the wafer 200 in a ring shape with the cutting blade 21 along the outer periphery of the wafer 200 while supplying cutting fluid 26 to the wafer 200, and also cuts the outer edge of the wafer 200 by changing the position of the cutting blade 21 in the radial direction of the wafer 200, and the amount of cutting fluid 26 supplied while cutting a position where at least a portion of the cutting edge 211 of the cutting blade 21 overlaps the outer peripheral edge 206 of the wafer 200 is set to be less than the amount of cutting fluid 26 supplied while cutting a position where the cutting blade 21 does not overlap the outer peripheral edge 206 of the wafer 200 (i.e., a position more inward than the outer peripheral edge 206).

[0060] In the wafer processing method according to the first embodiment, when the cutting device 1 forms an annular groove 210 of a desired depth 207 and a predetermined width along the outer peripheral portion including the outer peripheral edge 206 of the wafer 200 around the entire circumference of the wafer 200, the control unit 100 controls the moving unit 40 to move the cutting unit 20 away from the wafer 200 held on the holding table 10, and then moves the holding table 10 to the carry-in / out area. In the wafer processing method according to the first embodiment, the cutting device 1 stops suction holding of the wafer 200 on the holding table 10 in the carry-in / out area, and causes the transport unit to transport the wafer 200 from the holding table 10 to the cassette 51.

[0061] In the wafer processing method according to the first embodiment, the cutting device 1 sequentially cuts the wafers 200 in the cassette 51. In the wafer processing method according to the first embodiment, the cutting device 1 ends the wafer processing method, i.e., the processing operation, when it has cut all of the wafers 200 in the cassette 51.

[0062] Since the wafer 200 has a chamfered portion 205, the outer edge portion including the outer peripheral edge 206 is difficult to hold by suction on the holding table 10, and the outer edge portion, which is not held by suction, is prone to vibrate during cutting processing, and if the cutting fluid 26 gets into the gap between the wafer 200 and the holding surface 11, the processing quality is likely to deteriorate significantly.

[0063] However, in the wafer processing method and cutting device 1 according to embodiment 1, the amount of cutting fluid 26 supplied while the cutting edge 211 of the cutting blade 21 is cutting the position where it overlaps the outer peripheral edge 206 of the wafer 200 is set to be less than the amount of cutting fluid supplied while the cutting blade 21 is cutting the position where it does not overlap the outer peripheral edge 206 of the wafer 200.

[0064] For this reason, the wafer processing method and cutting device 1 according to embodiment 1 can reduce the possibility of cutting fluid 26 getting around to the back surface 202 of the wafer 200 held on the holding table 10 during cutting processing, and can also reduce the amount of cutting fluid 26 that gets around if it does, thereby preventing the wafer 200 from flapping around during cutting processing.

[0065] As a result, the wafer processing method and cutting device 1 according to the first embodiment have the effect of suppressing deterioration in processing quality.

[0066] Furthermore, the wafer processing method and cutting device 1 according to embodiment 1 cuts the wafer 200 by suction-holding the back surface 202 with a holding table 10 having a holding surface 11 of a size corresponding to the back surface 202, so that the wafer 200 can be reliably adsorbed to the holding surface 11 of the holding table 10.

[0067] The present invention is not limited to the above-described embodiment. In other words, various modifications can be made without departing from the gist of the present invention. In the embodiment, when the cutting edge 211 of the cutting blade 21 is caused to cut into the wafer 200 or when the cutting blade 21 is moved away from the wafer 200, the holding table 10 is moved in the X-axis direction, which is parallel to the horizontal direction. However, in the present invention, when the cutting edge 211 of the cutting blade 21 is caused to cut into the wafer 200 or when the cutting blade 21 is moved away from the wafer 200, the cutting blade 21 may be moved in the Z-axis direction.

[0068] That is, in the present invention, the cutting blade 21 may be caused to cut into the wafer 200 by a so-called chopper cut, and the cutting blade 21 that has cut into the wafer 200 may be raised and separated from the wafer 200. Also, in the present invention, the front surface 201, which is the first surface of the wafer 200, may be suction-held on the holding surface 11 of the holding table 10. [Explanation of symbols]

[0069] 1 Cutting equipment 10 Holding table (suction table) 11 Holding surface (adsorption area) 20 Cutting unit 21 Cutting blade 23 Spindle 25 Cutting fluid supply nozzle 26 Cutting fluid 200 wafers 201 Front (first side) 202 Back side (2nd side) 205 Chamfered part 206 Outer edge 253 Blade Cooler (Nozzle, 1st Nozzle, 2nd Nozzle)

Claims

1. A wafer processing method for cutting a wafer into an annular shape along the outer periphery of the wafer with a cutting blade, comprising: While supplying cutting fluid to the wafer, the wafer is annularly cut with the cutting blade along the outer periphery of the wafer, and the position of the cutting blade is changed in the radial direction of the wafer to cut the wafer; A wafer processing method in which the amount of cutting fluid supplied while the cutting blade is cutting a position that overlaps the outer peripheral edge of the wafer is set to be less than the amount of cutting fluid supplied while the cutting blade is cutting a position that does not overlap the outer peripheral edge of the wafer.

2. The cutting fluid is supplied to the wafer through the cutting blade by being sprayed toward the cutting blade from a pair of nozzles respectively disposed on both sides of the cutting blade in the thickness direction, While the cutting blade is cutting the position overlapping the outer peripheral edge of the wafer, the cutting fluid is sprayed only from the nozzle of the pair of nozzles that is closer to the center of the wafer; 2. The wafer processing method according to claim 1, wherein the cutting fluid is sprayed from both of the pair of nozzles while the cutting blade is cutting a position of the wafer that does not overlap the outer peripheral edge of the wafer.

3. the wafer has a first surface and a second surface behind the first surface, and a chamfered portion is formed on the outer periphery, so that the diameters of the first surface and the second surface are set smaller than the maximum outer diameter of the wafer; 3. The wafer processing method according to claim 1, wherein the wafer is cut by the cutting blade while the first surface side or the second surface side is adsorbed on an adsorption table having an adsorption area corresponding to the first surface or the second surface.

4. a holding table that holds the wafer; a cutting blade that cuts the wafer annularly along the outer periphery of the wafer held by the holding table; a cutting fluid supply nozzle for supplying cutting fluid to the wafer being cut by the cutting blade; cutting the wafer held by the holding table in an annular shape along the outer periphery of the wafer with the cutting blade while supplying cutting fluid to the wafer from the cutting fluid supply nozzle, and cutting the wafer by changing the position of the cutting blade in the radial direction of the wafer; A cutting device in which the amount of cutting fluid supplied while the cutting blade is cutting a position that overlaps the outer peripheral edge of the wafer is set to be less than the amount of cutting fluid supplied while the cutting blade is cutting a position that does not overlap the outer peripheral edge of the wafer.

5. the cutting fluid supply nozzle includes a first nozzle and a second nozzle respectively disposed on both sides of the cutting blade in a thickness direction; While the cutting blade is cutting the position overlapping the outer periphery of the wafer, the cutting fluid is supplied only from the nozzle of the first nozzle and the second nozzle that is closer to the center of the wafer, 5. The cutting device according to claim 4, wherein the cutting fluid is supplied from both the first nozzle and the second nozzle while the cutting blade is cutting a position that does not overlap the outer peripheral edge of the wafer.

6. the wafer has a first surface and a second surface behind the first surface, and a chamfered portion is formed on the outer periphery, so that the diameters of the first surface and the second surface are set smaller than the outer diameter of the wafer; 6. The cutting device according to claim 4, wherein the holding table has a suction area corresponding to the first surface or the second surface of the wafer.

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