Grindstone

Abstract

To provide a grindstone that can shorten washing time, has an excellent self-generated blade action and is hardly chipped.SOLUTION: A cutting grindstone 66 is comprised of abrasive grain, a binding agent, and hydrophilic powder.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a grinding stone.

Background Art

[0002] In a grinding apparatus for grinding a wafer, grinding chips are generated. However, by supplying grinding water during grinding, most of them are drained together with the grinding water. However, some of the grinding chips remain in the processing chamber together with the water vapor that fills the processing chamber when the grinding water becomes misty, and adhere to the processing chamber cover or the like. When the processing chamber cover is opened and closed after the inside of the processing chamber has dried, the grinding chips adhering to the cover scatter, contaminating the clean room where the grinding apparatus is placed.

[0003] Techniques related to such technical problems are described in, for example, Patent Document 1. Patent Document 1 describes a technique for cleaning a processing chamber cover to which grinding chips adhere.

[0004] In addition, for grinding hard workpieces such as sapphire and SiC in a grinding apparatus, a grinding stone in which abrasive grains are firmly held is used. However, such a grinding stone generally hardly exhibits a self-dressing effect. Therefore, it is necessary to perform dressing frequently, resulting in a decrease in productivity.

[0005] Techniques related to such technical problems are described in, for example, Patent Document 2. Patent Document 2 describes a technique for manufacturing a grinding stone in which a self-dressing effect is likely to occur by sintering an impregnated sponge body in which a spongy member is impregnated with fluid abrasive grains.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The technique described in Patent Document 1 washes away abrasive grains adhering to the inner wall of the processing chamber by injecting grinding water onto the inner wall after grinding. However, if the cleaning time is long, the throughput decreases, and the amount of water used for cleaning also increases, which is uneconomical.

[0008] The technique described in Patent Document 2 reduces the strength of the entire grinding wheel due to the configuration that promotes the self-sharpening action. Therefore, for example, when the grinding wheel contacts the workpiece, the impact when the grinding wheel contacts the outer peripheral edge of the workpiece, etc., the grinding wheel is likely to chip.

[0009] In the above, grinding has been described as an example, but the same problems can occur not only in grinding but also in all processing treatments using a grinding wheel such as cutting.

[0010] The present invention has been made in view of the above, and an object thereof is to provide a grinding wheel that can shorten the cleaning time, has a good self-sharpening action, and is less likely to chip.

Means for Solving the Problems

[0011] A grinding wheel according to one aspect of the present invention is a grinding wheel for cutting or grinding a workpiece, and comprises abrasive grains, a binder, and hydrophilic powder.

Effects of the Invention

[0012] According to the present invention, it is possible to provide a grinding wheel that can shorten the cleaning time, has a good self-sharpening action, and is less likely to chip.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0014] FIG. 1 is a perspective view of a processing device 1 according to an embodiment. FIG. 2 is a cross-sectional view of the processing device 1 according to an embodiment. The X-axis direction, Y-axis direction, and Z-axis direction shown in FIG. 1 are perpendicular to each other. The X-axis direction and Y-axis direction are substantially horizontal directions, and the Z-axis direction is the vertical direction (substantially vertical direction). First, the processing device 1 will be described with reference to FIGS. 1 and 2.

[0015] The processing device 1 is a processing device that holds a frame set on a chuck table 10 and processes a wafer W included in the frame set held on the chuck table 10 with a grinding stone. More specifically, the processing device 1 is a grinding device that grinds a wafer W, which is an example of a workpiece, using a grinding wheel 64 in which grinding stones 66 are arranged in a ring shape.

[0016] As shown in FIGS. 1 and 2, the processing device 1 includes a chuck table 10 that holds a frame set including a wafer W, a processing chamber cover 30 made of a resin plate (acrylic plate) or a metal plate (SUS plate) that defines a processing chamber, a grinding mechanism 60 that grinds the wafer W, and a processing feed mechanism 70 that is a moving mechanism for moving the grinding mechanism 60 in the Z-axis direction.

[0017] The wafer W processed by the processing apparatus 1 is not particularly limited. The wafer W may be, for example, a semiconductor substrate such as silicon, or may be a substrate with high hardness such as SiC or sapphire. As shown in FIG. 2, the frame set is formed by attaching the wafer W to the dicing tape T that closes the opening of the ring frame F, integrating the dicing tape T and the wafer W. Note that the wafer W is an example of the workpiece, and the workpiece processed by the processing apparatus 1 is not limited to the wafer W.

[0018] As shown in FIG. 1, a rectangular opening extending in the Y-axis direction is formed on the upper surface of the base 4 of the processing apparatus 1, and the chuck table 10 moves in the Y-axis direction within the opening of the base 4. This opening is covered with a bellows-shaped waterproof cover 3 that can move together with the chuck table 10. Below the waterproof cover 3, a moving mechanism 20 for moving the chuck table 10 in the Y-axis direction, a table rotation mechanism (not shown) for rotating the chuck table 10, and an inclination adjustment mechanism 40 for adjusting the inclination of the chuck table 10 are provided.

[0019] As shown in FIGS. 1 and 2, the chuck table 10 includes a porous plate 11, a frame body 12, and a frame clamp 13. The chuck table 10 is further connected to the table rotation mechanism and is configured to be rotatable around the rotation axis in the Z-axis direction by the drive of the table rotation mechanism.

[0020] As shown in FIG. 2, the porous plate 11 is fitted into a recess formed on the upper surface of the central portion of the frame body 12. The frame body 12 is formed with a suction path that communicates the upper surface of the recess into which the porous plate 11 is fitted and the suction source. A negative pressure is generated on the surface of the porous plate 11 by the suction operation of the suction source. The chuck table 10 sucks and holds the wafer W and the dicing tape T using the surface of the porous plate 11 where the negative pressure is generated as the holding surface 111.

[0021] As shown in FIG. 2, the frame clamp 13 is disposed outside the porous plate 11 and holds the ring frame F at a position lower than the holding surface 111. By holding the ring frame F at a position lower than the holding surface 111, interference between the grinding mechanism 60 and the frame clamp 13 can be avoided.

[0022] The moving mechanism 20 is a ball screw type electric slider. As shown in FIG. 1, it includes a ball screw 21 and a guide rail 22 extending in the Y-axis direction, a motor 23 connected to one end of the ball screw 21, and a slide portion 24 slidably installed on the guide rail 22. On the back surface of the slide portion 24, a nut portion (not shown) screwed onto the ball screw 21 is formed. In the moving mechanism 20, the rotation of the motor 23 causes the slide portion 24 to move in the Y-axis direction, and accordingly, the chuck table 10 fixed to the slide portion 24 moves in the Y-axis direction.

[0023] As shown in FIG. 1, the base 4 is provided with a height detection unit 50 disposed in the vicinity of the chuck table 10. The height detection unit 50 includes a support portion 51 vertically provided on the base 4, and two measurement probes 52 and 53 provided on the upper portion of the support portion 51. One probe 52 is disposed at a position where it can contact the upper surface of the wafer W held by the chuck table 10 and continuously measure the upper surface height of the wafer W. The other probe 53 is disposed at a position where it can contact the outer peripheral area at the same height as the holding surface 111 (see FIG. 2) of the chuck table 10 and continuously measure the upper surface height thereof.

[0024] Also, as shown in FIG. 1, the base 4 is provided with a processing chamber cover 30. The processing chamber cover 30 has a hole through which the spindle unit 61 of the grinding mechanism 60 is inserted, and covers the chuck table 10, the grinding wheel 64 of the grinding mechanism 60, and the height detection unit 50. The processing chamber cover 30 defines the space inside it as a processing chamber in order to limit the area allowing the scattering of grinding water, machining chips, etc.

[0025] Further, as shown in FIG. 1, a column 5 is erected on the base 4. The column 5 is provided with a machining feed mechanism 70 that feeds the grinding mechanism 60 in the Z-axis direction, which is a direction perpendicular to the holding surface 111. The machining feed mechanism 70 is a ball screw type electric slider, and as shown in FIG. 1, it includes a ball screw 71 and a guide rail 72 extending in the Z-axis direction, a motor 73 connected to one end of the ball screw 71, and a Z-axis stage 74 slidably installed on the guide rail 72. A nut portion (not shown) screwed onto the ball screw 71 is formed on the back side of the Z-axis stage 74. The machining feed mechanism 70 moves the Z-axis stage 74 in the Z-axis direction by the rotation of the motor 73. Along with this, the grinding mechanism 60 fixed to the Z-axis stage 74 moves in the Z-axis direction along the guide rail 72.

[0026] As shown in FIG. 1, the grinding mechanism 60 includes a spindle unit 61, a mount 62 provided at the lower end of the spindle unit 61, a holder 63 that surrounds the spindle unit 61 and is fixed to the Z-axis stage 74, and a grinding wheel 64 held on the lower surface of the mount 62. The grinding mechanism 60 is configured to rotate the grinding wheel 64 around the central axis by the spindle unit 61. The grinding wheel 64 is provided with a wheel base 65 and a plurality of grinding grains 66 annularly arranged on the lower surface of the wheel base 65.

[0027] Each of the plurality of grinding grains 66 contains abrasive grains, a binder, and hydrophilic powder. The abrasive grains are not particularly limited, and for example, may be general abrasive grains such as alumina or silicon carbide, or super abrasive grains such as diamond or cubic boron nitride (cBN). The binder is not particularly limited, but it is preferably a thermosetting resin that thermosets below the heat resistance temperature of the hydrophilic powder, or a two-component curable resin. Examples of the binder made of a thermosetting resin include, for example, resinoid bond, rubber, etc. Note that an ultraviolet curable resin may also be used.

[0028] The hydrophilic powder is for improving the water washability when grinding debris 103, which is the grinding wheel debris from the grinding wheel 66 ground by grinding, adheres to the inner wall of the processing chamber cover 30. This is because the grinding debris 103 contains the hydrophilic powder, thereby imparting hydrophilicity to the grinding debris 103. The hydrophilic powder is not particularly limited as long as it imparts hydrophilicity, but it is preferably a compound having a cellulose skeleton. More specifically, the hydrophilic powder is, for example, the product named "Leo Guard GP" manufactured by Lion Specialty Chemicals Co., Ltd. "Leo Guard GP" is a cationized cellulose mainly composed of polyquaternium-10 (quaternized hydroxyethyl cellulose).

[0029] As disclosed in Japanese Patent Application Laid-Open No. 2022-092482, since the hydrophilic powder is a cellulose skeleton, particularly a cationized cellulose skeleton, the hydrophilicity of the hydrophilic powder can be improved. Therefore, the interaction of the grinding debris 102 generated from the contact portion between the hydrophilic powder, the grinding wheel 66, and the wafer W is improved, and the so-called carryability of the grinding debris 102, which is the property that the cleaning water flows along the wall surface and carries the grinding debris 102 when flowing down, is improved. The grinding debris 103 is composed of abrasive grains, a binder, and a hydrophilic powder scraped off from the grinding wheel 66.

[0030] Examples of the cationized cellulose mainly composed of polyquaternium-10 include the Leo Guard series (such as "Leo Guard LP" and "Leo Guard MLP") manufactured by Lion Specialty Chemicals Co., Ltd. including the above-mentioned "Leo Guard GP", the Poise C series (such as "Poise C-150L") manufactured by Kao Corporation, and the UCARE (trademark) polymer series (such as "URCARE (trademark) JR-400") manufactured by Dow Chemical Japan Co., Ltd., etc., which have been commercialized. These cationized celluloses may be used for the hydrophilic powder constituting the grinding wheel 66.

[0031] In the processing apparatus 1 configured as described above, the grinding wheel 64 rotates at high speed due to the rotation of the spindle unit 61, and the chuck table 10 holding the wafer W rotates slowly in the same direction due to the rotation of the table rotation mechanism. In this state, while injecting the grinding water supplied from the grinding water supply source 80 shown in FIG. 2 to the central portion of the wafer W via the flow path 81 passing through the spindle unit 61 and the mount 62, the grinding mechanism 60 descends to the position where the grinding wheel 66 and the wafer W come into contact. As a result, the grinding wheel 66 moves while contacting the wafer W, and as a result, the wafer W is ground by the grinding wheel 66.

[0032] During the grinding of the wafer W, grinding chips 102 and grinding wheel chips 103 are generated from the contact portion between the grinding wheel 66 and the wafer W, and the liquid 100 in which the grinding water 101, the grinding chips 102, and the grinding wheel chips 103 are mixed scatters inside the processing chamber cover 30. Most of the grinding chips 102 and the grinding wheel chips 103 are drained together with the grinding water 101, but a part of them reaches the inner wall of the processing chamber cover 30 in a state of being mixed with the grinding water 101. As a result, as shown in FIG. 2, the liquid 100 in which the grinding water 101, the grinding chips 102, and the grinding wheel chips 103 are mixed adheres to the inner wall of the processing chamber cover 30.

[0033] Since the hydrophilic powder is blended in the grinding wheel 66 used in the processing apparatus 1 as described above, the grinding wheel chips 103 contained in the liquid 100 adhering to the inner wall also contain the hydrophilic powder. Therefore, the grinding wheel chips 103 contained in the liquid 100 adhering to the inner wall surface (wall surface) during grinding retain hydrophilicity.

[0034] The grinding wheel debris 103 with retained hydrophilicity is easily wetted by water due to its high affinity with water, improving the cleanability of the inner wall to which the grinding wheel debris 103 adheres. This is considered to be not only because the grinding wheel debris 103 is easily wetted by the grinding water 101, but also because the contact area between the grinding debris 102 and the wall surface decreases due to the volume increase caused by absorbing the grinding water 101. Therefore, even if the grinding debris 102 adheres to the wall surface, the grinding debris 102 can be easily removed from the wall surface together with the water (in this case, mainly the grinding water 101) containing the grinding wheel debris 103 that has flowed into the space between the grinding debris 102 and the wall surface.

[0035] Therefore, the processing apparatus 1 including the grinding wheel 66 containing the hydrophilic powder can make it difficult for the grinding debris 102 generated by grinding to adhere to the inner wall of the processing chamber cover 30 and can wash it away in a short time even if it adheres. Accordingly, the cleaning time of the processing chamber cover 30 can be shortened.

[0036] In addition, in the above, the inner wall of the processing chamber cover 30 has been focused on. However, the liquid 100 adheres not only to the inner wall of the processing chamber cover 30 but also to the surface of the wafer W. Also on the surface of the wafer W, the hydrophilicity of the grinding wheel debris 103 is retained in the same manner as the inner wall of the processing chamber cover 30. As a result, a high cleaning effect is also produced on the surface of the wafer W, so that the time required for the cleaning process of the wafer W performed after grinding can also be shortened.

[0037] Further, by blending the hydrophilic powder into the grinding wheel 66, even when a binder that firmly holds the abrasive grains is used, the grinding wheel 66 can achieve a good self-sharpening effect in which the cutting edge is maintained by the worn abrasive grains falling off and new abrasive grains being exposed. The good self-sharpening effect of the grinding wheel 66 is caused by the volume of the portion in contact with the grinding water 101 expanding due to the absorption of the grinding water 101, and as a result, the adhesive force of the binder in that portion locally decreases, promoting the falling off of the abrasive grains. Therefore, the grinding wheel 66 containing the hydrophilic powder is very useful in that it can promote the falling off of the abrasive grains on the lower surface (grinding surface) of the grinding wheel 66 to enhance the self-sharpening effect while preventing the entire grinding wheel 66 from becoming brittle and prone to chipping.

[0038] Note that the grinding wheel 66 may form a film on its side surface (the left and right exposed surfaces in FIG. 2) to prevent the adhesion of grinding water. That is, in addition to the abrasive grains, binder, and hydrophilic powder described above, the grinding wheel 66 may be provided with a film for preventing the adhesion of grinding water, and the film is formed on the side surface of the grinding wheel 66 so that at least the lower surface (grinding surface) of the grinding wheel 66 is exposed. Thereby, while realizing a good self-sharpening effect on the lower surface (grinding surface) of the grinding wheel 66, embrittlement of the side surface of the grinding wheel 66 can be prevented.

[0039] As described above, according to the grinding wheel 66 containing the hydrophilic powder and the processing apparatus 1 including the grinding wheel 66, a cleaning effect can be produced by the grinding debris 103 that maintains hydrophilicity on the inner wall of the processing chamber cover 30 and the surface of the wafer W during grinding. Therefore, it is difficult for the grinding debris 102 to adhere to the inner wall of the processing chamber cover 30 and the surface of the wafer W, and even if it adheres, it can flow down in a short time. Accordingly, by simply performing the processing using the grinding wheel 66 as usual, the cleaning time of the processing chamber cover 30 and the wafer W can be shortened. Also, adhesion of grinding debris to the ring frame F can be suppressed. Also, in the grinding wheel 64, adhesion of grinding debris can be suppressed.

[0040] Also, according to the grinding wheel 66 containing the hydrophilic powder and the processing apparatus 1 including the grinding wheel 66, a good self-sharpening effect can be realized without embrittling the entire grinding wheel 66. Therefore, it is possible to achieve both high grinding performance (self-sharpening effect) capable of grinding high-hardness workpieces such as SiC and sapphire and ease of handling (resistance to chipping) of the grinding wheel 66. In particular, by forming a waterproof film on the side surface of the grinding wheel 66, it is possible to achieve both a good self-sharpening effect and prevention of embrittlement of the grinding wheel 66 at a higher level.

[0041] The above-described effects are obtained because the grinding wheel 66 contains a hydrophilic powder. It is desirable that the hydrophilic powder be blended in a volume ratio of 10% or more and 30% or less with respect to the grinding wheel 66. By increasing the blending ratio of the hydrophilic powder, while the effect of shortening the cleaning time and the improvement of the self-sharpening action can be expected, the holding force of the abrasive grains on the grinding wheel surface may relatively decrease. However, by containing the hydrophilic powder at the above-described ratio, the force for holding the abrasive grains and the self-sharpening action can be highly balanced.

[0042] FIG. 3 is a diagram schematically showing the manufacturing process of the grinding wheel 66 according to an embodiment. Hereinafter, with reference to FIG. 3, an example of the manufacturing method of the grinding wheel 66 when a thermosetting resin is adopted as the binder will be described.

[0043] First, the raw materials of the grinding wheel 66 are mixed. FIG. 3(a) is a diagram schematically showing the mixing step of mixing the raw materials. Here, abrasive grains C1, a binder C2, and a hydrophilic powder C3 are put into the container 91 of the stirrer. It is desirable that the volume of the hydrophilic powder C3 put into the container 91 be appropriately adjusted so that the volume of the hydrophilic powder C3 contained in the grinding wheel 66 manufactured through the sintering process described later is 10% or more and 30% or less of the volume of the grinding wheel 66. Thereafter, the charged raw materials are stirred with the stirring rod 92 of the stirrer to obtain a mixture M1 in which the abrasive grains C1, the binder C2, and the hydrophilic powder C3 are approximately uniformly dispersed.

[0044] Next, the mixture M1 is compacted and molded. FIG. 3(b) is a diagram schematically showing the molding step. Here, the mixture M1 obtained in the mixing step is transferred to the mold 93. Thereafter, the mixture M1 is compacted and molded with the pressing tool 94 to obtain a molded product M2.

[0045] Finally, the molded product M2 is sintered. FIG. 3(c) is a diagram schematically showing the curing step. Here, after covering the mold 93 with the lid 95, the entire mold 93 with the molded product M2 is transferred to the firing furnace 96 and baked to obtain strength as a grinding wheel. Thereby, a grinding wheel M3 (grinding wheel 66) is obtained.

[0046] In the curing step shown in Fig. 3(c), heating is performed at a temperature equal to or lower than the heat-resistant temperature of the hydrophilic powder (for example, a temperature within the range of 100°C to 130°C). That is, as the binder C2, a resin binder that binds at a temperature equal to or lower than the heat-resistant temperature of the hydrophilic powder is used. By using a thermosetting resin as the binder C2, unlike the case where a UV-curable resin is used, for example, a situation where ultraviolet rays are reflected by the abrasive grains C1 and it is difficult for the inside of the molded product M2 to be cured does not occur, and it is possible to easily cure the inside. Further, by heating at a temperature equal to or lower than the heat-resistant temperature of the hydrophilic powder, it is possible to avoid deterioration of the characteristics of the hydrophilic powder, so that the effect of shortening the cleaning time by the hydrophilic powder can be obtained. Note that a UV-curable resin may be used as the resin binder.

[0047] When forming a waterproof film on the side surface of the grindstone, the film may be formed after the curing step shown in Fig. 3(c).

[0048] Further, the method for manufacturing the grinding wheel 66 is not limited to the method of forming the grindstone by heating as described above. That is, it may be possible to manufacture the grindstone without heating. For example, a two-component curable resin binder that cures by mixing two liquids, a liquid resin A and a liquid resin B, may be used.

[0049] When manufacturing a grindstone using this two-component curable resin binder, for example, the grindstone is manufactured by the following steps 1. to 4. Note that the liquid resin A is the main component of the two-component curable resin, and the liquid resin B is the curing agent of the two-component curable resin. 1. Charge abrasive grains and hydrophilic powder into the liquid resin A and stir. 2. Add the liquid resin B to the liquid resin A stirred in 1. and stir. 3. Put 2. into the grindstone mold and rotate the mold for 5 minutes for initial curing. 4. Remove the grindstone from 3. from the mold and leave it for 24 hours for complete curing.

[0050] Even when a two-component curable resin is used as the binder C2, it can be cured firmly to the inside in the same manner as when a thermosetting resin is used. Also, it is possible to avoid alteration of the properties of the hydrophilic powder, and the same applies to the effect of shortening the cleaning time.

[0051] Note that the embodiments of the present invention are not limited to the above embodiments, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way by technological progress or another derived technology, that method may be used for implementation. Therefore, the claims cover all embodiments that can be included within the scope of the technical idea of the present invention.

[0052] In the above-described embodiment, an example in which the raw material of the grinding wheel 66 includes abrasive grains, a binder, and hydrophilic powder was shown, but the binder may contain a filler.

[0053] In the above-described embodiment, the processing apparatus 1 including the grinding wheel 66 was exemplified, but the grinding wheel containing hydrophilic powder may be a cutting wheel, and the processing apparatus including the grinding wheel containing hydrophilic powder may be a cutting apparatus.

[0054] FIG. 4 is a perspective view of a processing apparatus 2 according to another embodiment. FIG. 5 is a cross-sectional side view of the processing apparatus 2 shown in FIG. 4. Hereinafter, with reference to FIGS. 4 and 5, the configuration of the processing apparatus 2, which is a cutting apparatus as an example of a processing apparatus, will be described.

[0055] The processing apparatus 2 is a processing apparatus that holds a wafer W on a chuck table 114 and processes the wafer W held on the chuck table 114 with a grinding wheel. More specifically, the processing apparatus 2 is a cutting apparatus that cuts a wafer W, which is an example of a workpiece, using a cutting blade 146.

[0056] On the base 104, a processing chamber cover 106 made of a resin plate (acrylic plate) or a metal plate (SUS plate) is placed. As shown in FIG. 5, the processing chamber cover 106 has an end wall 106a on the side opposite to the processing feed direction indicated by the arrow X1, an end wall 106b on the processing feed direction side, and a ceiling portion 106c.

[0057] Inside the processing chamber cover 106, a chuck table 114 is rotatably arranged and reciprocally movable in the X-axis direction by a processing feed mechanism (not shown). A water cover 116 is arranged around the chuck table 114, and a bellows 118 is provided between the water cover 116 and the base 104.

[0058] The space inside the processing chamber cover 106 is partitioned into a loading / unloading area 110 and a processing area 112 by a partition plate 108 arranged approximately in the middle in the X-axis direction of the processing chamber cover 106. The loading / unloading area 110 is an area for loading and unloading the workpiece on the chuck table 114, and the processing area 112 is an area for cutting the workpiece held on the chuck table 114. An opening 108a allowing the passage of the chuck table 114 is formed below the partition plate 108.

[0059] In addition, an air inlet 158 is provided on the loading / unloading area 110 side of the processing chamber cover 106, and an exhaust box 162 shown in FIG. 5 is provided on the processing area 112 side. The gas flowing into the processing chamber cover 106 from the air inlet 158 passes through the inside of the exhaust box 162 from the exhaust port 164 provided on the lower surface of the exhaust box 162 as shown by the arrow A in FIG. 4, and is exhausted outside the processing chamber cover 106 from the exhaust pipe connection port 165 formed on the ceiling portion 106c of the processing chamber cover 106.

[0060] On the base 104, a gantry column 120 is further erected. A pair of guide rails 122 extending in the Y-axis direction are fixed to the gantry column 120. The Y-axis moving block 124 moves in the Y-axis direction along the guide rails 122 by a Y-axis moving mechanism 128. The Y-axis moving mechanism 128 includes a ball screw 126 and a pulse motor (not shown).

[0061] A pair of guide rails 130 extending in the Z-axis direction are fixed to the Y-axis moving block 124. The Z-axis moving block 132 moves in the Z-axis direction along the guide rails 130 by a Z-axis moving mechanism 138. The Z-axis moving mechanism 138 includes a ball screw 134 and a pulse motor 136.

[0062] A cutting unit 140 and an alignment unit 142 having an imaging unit 143 are attached to the Z-axis moving block 132. A cutting blade 146 is attached to the tip of a spindle in a spindle housing 144 of the cutting unit 140. Approximately the upper half of the cutting blade 146 is covered by a wheel cover 148.

[0063] The cutting blade 146 may be a hub type cutting blade composed of a base and a grindstone constituting a cutting edge provided on the outer periphery of the base. Further, the cutting blade 146 may be a hubless type cutting blade composed only of a grindstone which is a cutting edge. For any type of cutting blade, the grindstone included in the cutting blade 146 is the same as the grinding grindstone 66. That is, the grindstone of the cutting blade 146 includes abrasive grains, a binder, and a hydrophilic powder, and the hydrophilic powder is blended at a volume ratio of 10% or more and 30% or less with respect to the binder.

[0064] As shown in FIG. 5, a blade cooler nozzle 149 and a shower nozzle 151 are attached to the wheel cover 148. When cutting the wafer W with the cutting blade 146, while ejecting a cutting fluid from the blade cooler nozzle 149 and the shower nozzle 151, the chuck table 114 is processed and fed in the direction of arrow X1. Since the cutting process is performed while supplying the cutting fluid, the cutting fluid 113 containing cutting chips due to the high-speed rotation of the cutting blade 146 scatters mainly toward the processing feed direction side.

[0065] The Y-axis protective bellows 150 protects the ball screw 125 from the droplets of the cutting fluid 113 and is attached at a position as shown in Fig. 2 so as to seal between the gantry column 120 and the Y-axis moving block 124. Further, the baffle plate 160 near the air inlet 158 formed on the ceiling portion 106c of the processing chamber cover 106 prevents the cutting fluid 113 rebounded by the side surface of the chuck table 114 or the wafer W held on the chuck table 114 from leaking out of the processing chamber cover 106 from the air inlet 158.

[0066] Also in the processing apparatus 2 according to the present embodiment, similarly to the processing apparatus 1, water containing machining chips and grinding chips scatters due to machining, and adheres to the inner wall surface of the processing chamber cover 106 and the wafer W. However, since the grinding wheel of the cutting blade 146 contains a hydrophilic powder, the scattered water also contains the hydrophilic powder. Therefore, also in the processing apparatus 2, similarly to the processing apparatus 1, it has the effect of suppressing the adhesion of machining chips (here, cutting chips) to the inner wall of the processing chamber cover 106 and the wafer W, and the effect that even if adhered, it can easily flow down. Therefore, the cleaning time of the processing chamber cover 106 and the wafer W can be shortened. Also, the cutting blade 146 has a high self-sharpening effect and can maintain the processing performance, which is the same as that of the processing apparatus 1. Further, the adhesion of grinding chips to the ring frame F can be suppressed. Also, in the blade cooler nozzle 149, the shower nozzle 151, the wheel cover 148, and the cutting blade 146 that supply the cutting water, the adhesion of machining chips can be suppressed.

[0067] A film for preventing the adhesion of water to the surface excluding the cutting surface (grinding wheel surface) may also be formed on the cutting grinding wheel of the cutting blade 146, similarly to the grinding wheel 66. That is, the film may be formed so that only the outer peripheral edge of the cutting blade 146 (cutting grinding wheel) is exposed. Thereby, while the hydrophilic powder swells only at the outer peripheral edge portion and the falling off of the abrasive grains is promoted, it is possible to avoid the other portions from being embrittled by water.

[0068] FIG. 6 is a table showing the experimental results regarding the consumption amount of the grinding wheel. FIG. 7 is a graph showing the relationship between the content of the hydrophilic powder and the consumption amount of the grinding wheel. FIG. 8 is a table showing the experimental results regarding the dirt removal of the processing chamber cover. Hereinafter, the experimental results obtained by the inventor of the present application will be described with reference to FIGS. 6 to 8.

[0069] The experiment was conducted using grinding wheels with different contents of cationized cellulose, and the consumption amount of the grinding wheel and the ease of dirt removal adhering to the processing chamber cover when each grinding wheel was used in the cutting device were compared. Specifically, five cases of 5%, 10%, 20%, 24.26%, and 30% of the volume ratio of cationized cellulose to the whole grinding wheel (grinding wheel A5, grinding wheel A10, grinding wheel A20, grinding wheel A24, grinding wheel A30) were compared. Since it becomes difficult to form the grinding wheel when the volume ratio of cationized cellulose exceeds 30%, the upper limit of the volume ratio was set to 30% and the experiment was conducted. In addition, in order to eliminate the influence of the material of the processing chamber cover, experiments were conducted on both of two types (acrylic plate, SUS plate) of processing chamber covers.

[0070] All the grinding wheels used in the experiment had diamond abrasive grains as the abrasive grains and a resinoid bond as the bond of the grinding wheel. The grinding wheel was fired and manufactured at a temperature below the heat-resistant temperature of cationized cellulose. Also, as shown in FIG. 6, the details of the processing conditions in the experiment are as follows. Rotation speed of the spindle: 20,000 revolutions / min Depth of cut: 0.3 μm Feed rate: 10 mm / s Number of cuts: 20

[0071] FIGS. 6 and 7 show that when the content of cationized cellulose is 10% or more, the result that the grinding wheel is consumed as compared with the case where no cationized cellulose is contained (see the consumption amount ratio) is shown. From this result, it can be confirmed that when the grinding wheel contains 10% or more of cationized cellulose, the self-sharpening action significantly occurs and the processing performance is maintained. The reference of the consumption amount ratio is the consumption amount in the grinding wheel that does not contain cationized cellulose.

[0072] In FIG. 8, regardless of the material of the processing chamber cover, it was confirmed that sufficient dirt removal was achieved when the cationized cellulose content was 10% or more (〇 in FIG. 8), while when the cationized cellulose content was 5%, dirt was still noticeable after cleaning (× in FIG. 8).

[0073] From the above results, it can be confirmed that it is desirable for the grinding wheel containing the hydrophilic powder to contain 10% or more of the hydrophilic powder by volume ratio with respect to the entire grinding wheel in terms of both the self-sharpening action and dirt removal.

Industrial Applicability

[0074] As described above, since the grinding wheel of the present invention contains the hydrophilic powder, it is possible to produce a cleaning effect due to the hydrophilicity of the hydrophilic powder attached to the processing chamber where the grinding wheel is used. As a result, the cleaning time can be shortened. In addition, since the self-sharpening action can be enhanced without embrittling the entire grinding wheel, high processing performance and ease of handling can be achieved simultaneously. Therefore, it is very useful in cutting, grinding, especially in the processing of workpieces with high hardness.

Explanation of Reference Numerals

[0075] 1: Processing apparatus 10, 114: Chuck table 30, 106: Processing chamber cover 60: Grinding mechanism 64: Grinding wheel 65: Wheel base 66: Grinding stone 80: Grinding water supply source 91: Container 93: Mold 94: Pressing tool 95: Lid 96: Firing furnace 100: Liquid 101: Grinding water 102: Grinding chips 103: Stone chips 111: Holding surface 113: Cutting fluid 140: Cutting unit 146: Cutting blade 148: Wheel cover 149: Blade cooler nozzle 151: Shower nozzle C1: Abrasive grains C2: Binder C3: Hydrophilic powder M1: Mixture M2: Molded product M3: Grinding wheel W: Wafer

Claims

1. A grinding wheel for cutting or grinding a workpiece, comprising abrasive grains, a binder, and a hydrophilic powder.

2. The grinding wheel according to claim 1, wherein the hydrophilic powder is blended with the grinding wheel in a volume ratio of 10% or more and 30% or less.

3. The grinding wheel according to claim 1 or claim 2, wherein the hydrophilic powder has a cellulose backbone.

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