TW201912310A - processing methods - Google Patents

Abstract

To smoothly perform processing while suppressing wear of a processing grinding stone in the case of processing a workpiece formed of a hard-to-cut material or the like. A processing method includes: a holding step of holding a workpiece by a holding table having a holding surface for holding a workpiece; and a processing step of processing the workpiece by a processing mechanism having a processing grinding stone after performing the holding step. The processing grinding stone is made of a ceramic binding agent in combination with abrasive grains. In addition, in the processing step, processing water is supplied to the workpiece, and a processing surface of the processing grinding stone is irradiated with light of a predetermined wavelength from light irradiation mechanism.

Description

processing method

FIELD OF THE INVENTION The present invention relates to a processing method for processing an object by using a processing grindstone, which is made of a ceramic binder and abrasive grains.

BACKGROUND OF THE INVENTION After a plate-shaped workpiece such as a semiconductor wafer is ground to a predetermined thickness after being ground, it is divided into individual element wafers by slicing, and then used in various electronic devices and the like. Then, when a wafer is formed of a hard-to-cut material such as gallium nitride (GaN), silicon carbide (SiC), or gallium arsenide (GaAs), the following methods are widely used: the use of a ceramic binder to bond abrasive grains A grinding method of the manufactured grinding stone (for example, refer to Patent Document 1) and a cutting method using a cutting grindstone made by combining abrasive grains with a ceramic binder (for example, see Patent Document 2). Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2014-124690 Patent Document 2: Japanese Patent Laid-Open No. 2013-219215

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, in any of the above methods, there is a problem that the amount of grinding stone wear is far above the demand and the production cost is increased. In addition, when processing a workpiece formed of a difficult-to-cut material, there is a problem that the processing ability of a grindstone is reduced and productivity is reduced. Moreover, when using a grindstone to process a to-be-processed object containing a metal at a processing position, there is also a problem that it becomes difficult to process due to the ductility of the metal.

For this reason, when processing a to-be-processed object formed from a difficult-to-cut material or the like, there is a problem that it is possible to suppress excessive abrasion of the processing grindstone and to perform stable processing smoothly. Problems to be solved

The present invention for solving the above-mentioned problems is a processing method and a processing method of a workpiece, comprising: a holding step for holding the workpiece on a holding table having a holding surface for holding the workpiece; and a processing step for carrying out the processing After the holding step, the object to be processed is processed by a processing mechanism including a processing grindstone, which is made of a ceramic binder in combination with abrasive grains. In this processing step, processing water is supplied to the object to be processed, and A light of a predetermined wavelength is irradiated from the light irradiation means to the processing surface of the processing grindstone.

The present invention for solving the above-mentioned problems is a processing method in which the processing mechanism includes a cutting blade provided with the processing grindstone, and in the processing step, the workpiece is cut with the cutting blade.

The present invention for solving the above-mentioned problems is a processing method in which the processing mechanism includes a grinding wheel including the processing grindstone, and in the processing step, a workpiece is ground with the grinding wheel. Invention effect

A method for processing a workpiece according to the present invention includes: a holding step for holding the workpiece with a holding table having a holding surface for holding the workpiece; and a processing step for carrying out the holding step by a processing mechanism including a grinding stone. The processed grinding stone is made of a ceramic binder combined with abrasive grains. In the processing step, processing water is supplied to the workpiece, and the processing surface of the processed grinding stone is irradiated with a predetermined wavelength from a light irradiation mechanism. By this, for example, the processing grindstone can be made hydrophilic to enhance the cooling effect brought by the processing water, thereby suppressing excessive wear of the processing grindstone, and improving the discharge of processing debris. In addition, due to the hydrophilization of the processing grindstone, processing water is effectively supplied to the processing area of the processing grindstone, so that the deterioration of the processing quality caused by the processing heat can be prevented, even if the workpiece is formed of a difficult-to-cut material The wafer can also be stably processed.

(Embodiment 1) The grinding device 1 shown in FIG. 1 is a device for grinding a workpiece W held on a holding table 30 by a machining mechanism 7 including a grinding wheel 74. The front side (-Y direction side) on the base 10 of the grinding device 1 is a loading and unloading area A, that is, an area for loading and unloading the workpiece W on the holding table 30, and the rear on the base 10 is a processing area B. That is, the area where the workpiece W is ground by the processing mechanism 7. An input mechanism 12 is provided on the front side of the base 10 for an operator to input processing conditions and the like to the grinding device 1.

The holding table 30 has, for example, a circular shape, and includes a suction unit 300 that suctions the workpiece W, and a frame 301 that supports the suction unit 300. The suction part 300 is connected to a suction source (not shown), and sucks and holds the workpiece W on the holding surface 300 a that is the exposed surface of the suction part 300. The holding surface 300 a of the holding table 30 is formed as a conical surface having an extremely gentle inclination with the rotation center of the holding table 30 as a vertex. The holding table 30 is surrounded by the cover 31 from the surroundings, and can be rotated around the axis in the Z-axis direction. The Y-axis direction feeding mechanism can be used in the Y-axis direction between the loading area A and the processing area B. The Y-axis direction feed mechanism is disposed below the cover 31 and the telescopic cover 31 a connected to the cover 31.

A column portion 11 is erected on the processing area B. A grinding feed mechanism 5 is disposed on the side of the column portion 11. The grinding feed mechanism 5 feeds the processing mechanism 7 in the Z-axis direction. The grinding feed mechanism 5 is composed of a ball screw 50, a pair of guide rails 51, a motor 52, a lifting plate 53, and a bracket 54. The ball screw 50 has an axial center in the Z-axis direction. The ball screw 50 is arranged in parallel. The motor 52 is connected to the upper end of the ball screw 50 and rotates the ball screw 50. The lifting plate 53 screwes the internal nut to the ball screw 50 and slides the side to the guide rail. 51. The bracket 54 is connected to the lifting plate 53 and holds the processing mechanism 7. When the ball screw 50 is rotated by the motor 52, the lifting plate 53 is guided by the guide rail 51 and moves back and forth in the Z-axis direction along with this. In order to grind the machining mechanism 7 held on the bracket 54 in the Z-axis direction.

The processing mechanism 7 is provided with a rotation shaft 70 in the Z-axis direction; a housing 71 supporting the rotation shaft 70 so as to be rotatable; a motor 72 rotatingly driving the rotation shaft 70; and a base 73 connected to the front end of the rotation shaft 70 And grinding wheel 74, which is detachably mounted on the lower surface of the base 73.

The grinding wheel 74 is composed of a ring-shaped wheel base 74b and a plurality of approximately rectangular parallelepiped-shaped grinding stones 74a. The plurality of substantially rectangular parallelepiped-shaped grinding stones 74a are arranged annularly on the bottom surface of the wheel base 74b. (Free end). The processing grindstone 74a is made of a glassy and ceramic bonding agent, namely, a ceramic bonding agent and diamond abrasive grains. As the ceramic binder, for example, silicon dioxide (SiO2) is the main component, and a small amount of additives can be added to control the melting point. In addition, the shape of the processing grindstone 74a may be formed in an integrated ring shape.

Inside the rotating shaft 70 shown in FIG. 1, a flow path 70 a that communicates with the processing water supply mechanism 8 and serves as a channel for the processing water is provided in the axial direction (Z-axis direction) of the rotating shaft 70 and passes through the flow path 70 a. The processing water can be sprayed from the wheel base 74b toward the processing grindstone 74a through the bed 73.

The processing water supply mechanism 8 shown in FIG. 1 includes, for example, a processing water source 80 that stores water (e.g., pure water), a piping 81 connected to the processing water source 80 and communicating with the flow path 70a, and an adjustment valve 82 disposed on the piping. Any position on 81 to adjust the flow of process water.

As shown in FIGS. 1 and 2, the grinding device 1 is provided with a light irradiation mechanism 9, which is arranged adjacent to the holding table 30, for example, and irradiates the processing surface (lower surface) of the processing grindstone 74 a with a predetermined wavelength. Lightly, the processing grindstone 74 a is ground to hold the workpiece W held by the stage 30. As shown in FIG. 2, the light irradiation mechanism 9 includes, for example, a table portion 90 having a substantially arc-shaped outer shape, and a plurality of light emitting portions 91 disposed on the upper surface of the table portion 90 (in the example shown in the figure). There are four) in parallel; the washing water supply unit 92 supplies washing water (for example, pure water) toward the light emitting unit 91; and the cover 93 prevents dirt from adhering to the light emitting unit 91.

The light-emitting portion 91 embedded in the cavity formed on the upper surface of the table portion 90 is, for example, a low-pressure mercury lamp or UVLED, which can emit light of a predetermined wavelength, and can be switched on / off by a switch (not shown). The light emitting section 91 can emit light of two wavelengths, for example, and preferably emits light of a wavelength of 80 nm to 200 nm and light of a wavelength of 240 nm to 280 nm. The light emitting section 91 is more preferably capable of emitting light having a wavelength of 365 nm. The light-emitting portion 91 in this embodiment is a two-wavelength LED or a low-pressure mercury lamp, and can simultaneously emit ultraviolet light having a wavelength of 184.9 nm and ultraviolet light having a wavelength of 253.7 nm.

The plate-shaped cover 93 is made of, for example, a transparent member such as glass that can transmit light generated by the light-emitting portion 91, and is fixed to the upper surface of the table portion 90 so as to cover the light-emitting portion 91. For example, the table portion 90 can be moved up and down by a Z-axis direction moving mechanism (not shown). When the grinding process is performed, the height position of the upper surface of the cover 93 can be set to take into account the grinding stone 74a. The expected height position of the grinding feed position.

The washing water supply unit 92 includes, for example, a washing water source (not shown) that stores water (for example, pure water), and a washing water nozzle 920 that communicates with the washing water source. The washing water nozzle 920 is, for example, fixed to the side surface of the table part 90 along the table part 90, and a plurality of spraying ports 920a are arranged in a row along the longitudinal direction. The spraying ports 920a can spray the washing water toward the upper surface of the cover 93. . The spray port 920 a is configured to set the shape, the size, the angle with respect to the light emitting section 91, and the like so that the sprayed washing water can be cleared and fluidized on the upper surface of the cover 93. The spray port 920a is preferably formed in a narrow slit shape as shown in FIG. 2 and a plurality of spray ports 920a are arranged on the side of the washing water nozzle 920, but is not limited thereto. For example, the spray port 920a may be formed in a circular hole shape, and a plurality of spray ports 920a may be arranged on the side surface of the washing water nozzle 920. Alternatively, the spray port 920a may be formed in a narrow slit shape extending continuously on the side of the washing water nozzle 920 or the like.

Hereinafter, each step of the machining method and the operation of the grinding device 1 when the machining method of the present invention is implemented using the grinding device 1 shown in FIG. 1 will be described step by step. The processed object W having a circular plate shape shown in FIG. 1 is, for example, a semiconductor wafer formed of SiC, which is a hard-to-cut material. On the front surface Wa of the processed object W facing downward in FIG. A plurality of elements are formed in a grid-like region divided by a predetermined division line, and a protective tape T for protecting the front surface Wa is attached. The back surface Wb of the workpiece W becomes a ground surface to be ground by the grinding wheel 74. In addition, the shape and type of the workpiece W are not particularly limited, and may be appropriately changed according to the relationship with the grinding wheel 74. It also includes wafers made of GaAS or GaN, or crystals made of metal. Wafers with round or metal electrodes partially exposed on the back of the wafer.

(1) Holding step First, in the loading / unloading area A, the workpiece W is placed on the holding surface 300a of the holding table 30 so that the back surface Wb becomes the upper side. Then, the suction force generated by a suction source (not shown) is transmitted to the holding surface 300a, whereby the holding table 30 sucks and holds the workpiece W on the holding surface 300a. The workpiece W is in a state of being attracted and held in close contact with the holding surface 300a, which is a gentle conical surface.

(2) Machining step The holding table 30 is moved below the processing mechanism 7 by the Y-axis direction feeding mechanism (not shown), and the grinding wheel 74 and the workpiece W held on the holding table 30 are performed. Counterpoint. The alignment is performed, for example, by shifting the rotation center of the grinding wheel 74 with respect to the rotation center of the workpiece W in a + Y direction by a predetermined distance, and passing the rotation locus of the processing grindstone 74a through the workpiece W. Center of rotation. Further, the inclination of the holding table 30 is adjusted so that the flat conical surface, that is, the holding surface 300a, is parallel to the lower surface of the processing stone 74a, that is, the processing surface, so that the back surface Wb of the workpiece W is relative to the The working surface becomes parallel.

After the grinding wheel 74 is aligned with the workpiece W, as the rotary shaft 70 is driven by the motor 72 to rotate, as shown in FIG. 3, the grinding wheel 74 is viewed in a reverse direction when viewed from the + Z direction side. Rotate clockwise. In addition, the grinding mechanism 74 feeds the machining mechanism 7 in the -Z direction by the grinding feed mechanism 5, and the grinding wheel 74 provided in the machining mechanism 7 gradually descends in the -Z direction, so that the grinding stone 74a abuts on the workpiece W. The back surface Wb is thus ground. In addition, during grinding, as the holding table 30 rotates counterclockwise when viewed from the + Z direction side, the workpiece W also rotates. Therefore, the grinding stone 74a performs the back surface Wb of the workpiece W. Grinding of the entire surface.

During the grinding process, the processing water supply mechanism 8 supplies processing water to the flow path 70 a in the rotary shaft 70. As shown in FIG. 3, the processing water supplied to the flow path 70a passes through the flow path 73b formed at a constant interval in the circumferential direction of the frame 73 inside the frame 73, and is sprayed from the wheel base 74b. The port 74d is sprayed toward the processing grindstone 74a.

The workpiece W is attracted and held against the holding surface 300a, which is the gentle conical surface of the holding table 30, that is, the holding surface 300a. Therefore, the rotation track of the grinding wheel 74 shown by a two-point chain line in FIG. 4 (A) In the middle region E (hereinafter referred to as the processing region E), the processing grindstone 74 a abuts on the workpiece W and performs grinding.

The light irradiation mechanism 9 disposed adjacent to the holding table 30 is, for example, in a state where the alignment of the grinding wheel 74 and the holding table 30 has been completed, and the grinding wheel 74 is about to enter to hold the workpiece W held by the holding table 30. Previously, that is, immediately before the processing grindstone 74 a entered the processing area E, it was placed on the rotation track of the holding table 30 and the grinding wheel 74 as shown in FIG. 4 (A).

With the start of the grinding process, as shown in FIG. 4 (B), the light emitting section 91 is turned on, and the light emitting section 91 is irradiated with ultraviolet light having a wavelength of 184.9 nm and ultraviolet light having a wavelength of 253.7 nm in the + Z direction, for example. The irradiated light passes through the cover 93 and irradiates the lower surface of the processing grindstone 74 a immediately before entering the processing area E.

By irradiating ultraviolet light with a wavelength of 184.9 nm to the lower surface of the processing millstone 74a immediately before entering the processing area E, oxygen molecules existing in the air between the lower surface of the processing millstone 74a and the light-emitting portion 91 will absorb ultraviolet light. And generate an oxygen atom in the ground state. The generated oxygen atoms will bond with the surrounding oxygen molecules to generate ozone. In addition, the ultraviolet light with a wavelength of 184.9 nm cuts off the intermolecular bonds and interatomic bonds caused by the organic pollution caused by the grinding debris adhering to the working surface of the processing grindstone 74a, thereby breaking the organic state, thereby decomposing organic matter. Pollution. In addition, the generated ozone absorbs ultraviolet light with a wavelength of 253.7 nm, thereby generating active oxygen in an excited state. Because active oxygen or ozone has high oxidizing power, it will bond with carbon or hydrogen generated on the processing surface of the processing stone 74a, and form polarities such as hydroxyl group, aldehyde group, and carboxyl group on the processing surface of the processing stone 74a. Large hydrophilic group. As a result, the processing grindstone 74a becomes hydrophilic, and the processing water will not easily become water droplets on the processing surface of the processing grindstone 74a, and the processing water will easily spread into a water film shape on the entire processing surface of the processing grindstone 74a.

The processed grinding stone 74a that has been hydrophilized enters the processing area E with a large amount of processing water, and grinds the back surface Wb of the workpiece W. More processing water enters the contact portion between the back surface Wb of the workpiece W and the processing surface of the processing grindstone 74a, whereby the generation of frictional heat at the contact portion can be suppressed.

As shown in FIG. 5, during the grinding process, the washing water supply unit 92 supplies washing water toward the upper surface of the cover 93. That is, washing water is supplied from a washing water source (not shown) to the washing water nozzle 920, and the washing water is ejected from the injection port 920a toward the outside of the nozzle and reaches the cover 93 like a parabola. Then, while the water flow of the washing water is moderately rectified, the contamination of the grinding chips and the like attached to the cover 93 is removed, thereby maintaining the grinding, and the light generated by the light emitting portion 91 is appropriately irradiated to the processing. The state of the processed surface of the grindstone 74a.

The method for processing a workpiece according to the present invention includes a holding step for holding the workpiece W with a holding table 30 having a holding surface 300a for holding the workpiece W; and a processing step for including a processing grindstone after the holding step is performed. The processing mechanism 7 of 74a grinds and processes the workpiece W. The grinding stone 74a is made of a ceramic binder in combination with abrasive grains. In the processing step, processing water is supplied to the workpiece W and is irradiated with light. The mechanism 9 irradiates the processing surface of the processing grindstone 74a with light of a predetermined wavelength, thereby allowing more processing water to enter the contact portion between the back surface Wb of the workpiece W and the processing surface of the processing grindstone 74a, thereby suppressing occurrence of The generation of frictional heat at the contact portion further suppresses the abrasion of the processing grindstone 74a (exceeding abnormal wear that would promote proper self-sharpening). In addition, the grinding water generated at the contact portion between the back surface Wb of the workpiece W and the processing surface of the processing grindstone 74a can be efficiently removed by the processing water. In addition, the hydrophilization of the processing grindstone 74a effectively supplies the processing water to the processing area E where the processing grindstone 74a grinds the workpiece W, so that it is possible to prevent the occurrence of wafer scorch and the like due to an increase in processing heat. The processing quality deteriorates, and even if the workpiece W is a wafer formed of a difficult-to-cut material, stable grinding can be smoothly performed.

The inventors of the present invention conducted the following experiment 1 in order to verify the effect of irradiating the working surface of the processing grindstone with light having a wavelength of 365 nm in the processing steps of the processing method of the present invention. In Experiment 1, a soda glass plate having a thickness of 10 mm was used as the circular plate-shaped workpiece W. In addition, the grinding stone 74a of the grinding wheel 74 is a grinding stone made by bonding diamond abrasive grains having a particle size of ♯1000 with a ceramic binder.

In Experiment 1, after the holding step was performed, the processing steps were performed under the processing conditions shown below. Number of rotations of grinding wheel 74 (rpm): 2000 rpm Number of rotations of holding table 30 (rpm): 300 rpm Grinding feed rate (falling speed) of grinding wheel 74: 0.5 μm / sec In Experiment 1, in the processing step Using an LED lamp as the light emitting portion 91 of the light irradiation mechanism 9 shown in FIG. 2, the lower surface of the grinding stone 74 a of the grinding wheel 74 is irradiated with ultraviolet light having a wavelength of 365 nm and the workpiece W is ground by 50 μm. The lower surface of the processing grindstone 74 a is irradiated with ultraviolet light from the light emitting portion 91 and the workpiece W is ground by 50 μm, and the grinding with and without the ultraviolet light is repeatedly and continuously performed. The supply of the processing water to the processing grindstone 74a is performed in the same manner as the processing steps described above.

The tracing point diagram P1 shown in FIG. 6 is a diagram obtained by tracing the measured value obtained in Experiment 1. In the tracing point diagram P1, the horizontal axis represents the grinding wheel 74 when the workpiece W is ground by 50 μm. The consumption (μm) of the processing grindstone 74a, and the vertical axis represents the maximum processing load (N) that the grinding wheel 74 is subjected to during grinding of the workpiece W by 50 μm. In the case of grinding while irradiating ultraviolet light, the consumption value of the processing grindstone 74a and the maximum processing load value carried by the grinding wheel 74 are represented by dots in the tracing diagram P1, and are The transition is represented by a graph G1 indicated by a dotted line, so that the transition can be easily grasped. In addition, the consumption value of the processing grindstone 74a and the maximum processing load value of the grinding wheel 74 measured when the grinding is performed without irradiation with ultraviolet light are represented by triangular points in the tracing point diagram P1, Moreover, the transition is represented by a graph G2 represented by a single-dot chain line, so that the transition can be easily grasped.

As can be read from the tracing point diagram P1, when the grinding process of the workpiece W is performed while irradiating the lower surface of the grinding wheel 74a of the grinding wheel 74 with ultraviolet light having a wavelength of 365 nm, When the ultraviolet light is irradiated, the consumption of the processing grindstone 74a and the load that the grinding wheel 74 receives during grinding can be reduced. If the machining load on the grinding wheel 74 can be reduced like this, the load on the motor 52 of the grinding feed mechanism 5 shown in FIG. 1 can be reduced, or the ball screw 50 can be prevented from being caused by the machining load. A backlash occurred. In addition, in a case where the processing load carried by the grinding wheel 74 is compared with the same load, the case of grinding while irradiating the lower surface of the grinding wheel 74a of the grinding wheel 74 with ultraviolet light having a wavelength of 365 nm is compared. In the case where the ultraviolet light is not irradiated, the consumption of the processing grindstone 74a can be reduced by about 20%.

(Embodiment 2) The cutting device 2 shown in FIG. 7 performs a cutting process by rotating and cutting the cutting blade 210 included in the processing mechanism 21 with respect to the workpiece W held on the holding surface 200a of the holding table 20 Device.

A cutting feed mechanism 22 is provided on the base 2A of the cutting device 2 to move the holding table 20 back and forth in the cutting feed direction (X-axis direction). The cutting feed mechanism 22 is composed of a ball screw 220, a pair of guide rails 221, a motor 222, and a movable plate 223. The ball screw 220 has an axial center in the X-axis direction. The pair of guide rails 221 are parallel to the ball screw 220 It is provided that the motor 222 rotates the ball screw 220, and the movable plate 223 is screwed with the inner nut to the ball screw 220 and the bottom is slidably connected to the guide rail 221. Then, when the ball screw 220 is rotated by the motor 222, the movable plate 223 is guided by the guide rail 221 to move in the X-axis direction, and the holding table 20 provided on the movable plate 223 is also moved at X Move in the axis direction.

The holding table 20 disposed on the movable plate 223 has, for example, a circular shape, and includes a suction section 200 made of a porous member and sucking a workpiece W, and a frame 201 supporting the suction section 200. The suction unit 200 is connected to a suction source (not shown), and sucks and holds the workpiece W on the holding surface 200 a that is the exposed surface of the suction unit 200. The holding table 20 can be rotated by a rotation mechanism 202 provided on the bottom surface side of the holding table 20. In the illustrated example, four fixing jigs 204 are arranged around the holding table 20 at regular intervals.

From the center on the base 2A to the rear side (+ Y direction side), an index feed mechanism 23 is provided to move the processing mechanism 21 back and forth in the Y axis direction. The indexing feed mechanism 23 is composed of a ball screw 230, a pair of guide rails 231, a motor 232, and a movable portion 233. The ball screw 230 has an axial center in the Y-axis direction. The pair of guide rails 231 is parallel to the ball screw 230. The motor 232 is configured to rotate the ball screw 230, and the movable portion 233 is configured to screw the inner nut to the ball screw 230 and slide the bottom to the guide rail 231. When the ball screw 230 is rotated by the motor 232, the movable portion 233 is guided by the guide rail 231 to move in the Y-axis direction, and the processing mechanism 21 is moved in the Y-axis along with the movement of the movable portion 233. Move in the direction.

The movable portion 233 is integrally provided with a pillar portion 234, and a cutting feed mechanism 24 for moving the machining mechanism 21 up and down in the Z-axis direction is provided on the side of the -X direction side of the pillar portion 234. The cut-in feed mechanism 24 is composed of a ball screw 240, a pair of guide rails 241, a motor 242, and a support member 243. The ball screw 240 has an axial center in the Z-axis direction. The pair of guide rails 241 is parallel to the ball screw 240. It is provided that the motor 242 rotates the ball screw 240, and the support member 243 is screwed with the inner nut to the ball screw 240 and the side portion is slidably connected to the guide rail 241. Then, when the ball screw 240 is rotated by the motor 242, the supporting member 243 is guided by the guide rail 241 to move in the Z-axis direction, so that the processing mechanism 21 supported by the supporting member 243 is moved in the Z-axis direction. Cut-in feed.

The processing mechanism 21 includes a main shaft 211 whose axial direction is a direction (Y-axis direction) orthogonal to the moving direction (X-axis direction) of the holding table 20 in a horizontal direction; and a housing 212 that supports the main shaft 211 to be rotatable. A motor (not shown) housed inside the housing 212 and rotationally drives the main shaft 211; and a cutting blade 210 installed at the front end portion of the -Y direction side of the main shaft 211, and the main shaft 211 is rotationally driven by the motor The cutting blade 210 will also rotate at high speed.

An alignment mechanism 25 is provided on the side of the housing 212 to capture the workpiece W to detect the position where the cutting blade 210 cuts in. The calibration mechanism 25 includes a calibration camera 250 that captures the cut surface of the workpiece W. Based on the image obtained by the calibration camera 250, it is possible to detect the target by image processing such as pattern matching. A predetermined division line S to be cut on the work W.

The cutting blade 210 shown in FIG. 8 is, for example, a washer-type blade provided with a mounting hole in the center and having a ring-shaped outer shape. For example, the cutting blade 210 is made of glass and ceramic bonding agent, namely, a ceramic bonding agent and diamond abrasive grains. As a ceramic bonding agent, for example, silicon dioxide (SiO2) is used as a main component, and a small amount is mixed therein. Feldspar and other binders. The cutting blade 210 is sandwiched from both sides of the Y-axis direction by an attachment flange 218 and a base flange (not shown), and is attached to the main shaft 211 by being fastened with a fixing nut 217. In addition, the cutting blade 210 may be a hub-type cutting blade in which a processing grindstone is provided so as to protrude outward in the radial direction on a base made of aluminum or the like.

As shown in FIGS. 7 and 8, the processing mechanism 21 includes, for example, a blade cover 219 that covers the cutting blade 210. The blade cover 219 is provided with an opening for accommodating the cutting blade 210 in a substantially central portion thereof, and by being installed in the housing 212, the cutting blade 210 can be positioned on the opening and covers the cutting blade 210 from above.

A support block 213 is fastened to the -X direction side end of the blade cover 219, and the support block 213 can be moved in the Z-axis direction by an adjusting screw 213a. A pair of processing water nozzles 214 is fixed to the support block 213. The processing water is supplied from the supply pipe 213b to the pair of processing water nozzles 214 through the support block 213. The pair of processing water nozzles 214 are configured to sandwich the lower portion of the cutting blade 210 from both sides of the side of the cutting blade 210 and extend toward the + X direction side in parallel with each other. A plurality of slits are arranged in the X-axis direction at positions facing the cutting blade 210 on the front end side of the pair of processing water nozzles 214, and processing water is sprayed from the side through the plurality of slits to perform cutting. The contact area between the blade 210 and the workpiece W is cooled. A pair of droplet covers 213c are provided at the lower end of the support block 213 to direct the sprayed processed water to the -X direction side.

A processing water block 215 is fastened to the + X direction side end of the blade cover 219, and the processing water block 215 can be slid in the Y-axis direction by an adjusting screw 215a. As shown in FIG. 8, a processing water nozzle 216 that sprays processing water on the cutting blade 210 from the outer peripheral direction of the cutting blade 210 is disposed in the processing water block 215. The upper end of the processing water nozzle 216 communicates with a supply pipe 215b, and the processing water spraying port 216a, which is the lower end of the processing water nozzle 216, opens toward the front end surface (processing surface) of the cutting blade 210. The processing water nozzle 216 sprays the processing water from the outer direction toward the cutting blade 210, thereby winding the processing water into the rotating cutting blade 210, together with the cutting chips generated at the contact portion between the cutting blade 210 and the workpiece W. It is pushed out toward the -X direction, thereby cleaning and cooling the contact area.

The cutting device 2 is provided with a light irradiation mechanism 4 which irradiates the processing surface (the front end surface of the blade) of the cutting blade 210 with light of a predetermined wavelength. The light irradiation mechanism 4 includes, for example, a light emitting section 40 composed of, for example, a low-pressure mercury lamp or a UV LED, and a power source 41 for switching on / off of the light emitting section 40.

The light emitting section 40 is disposed on the processing water block 215 so as to face the processing surface of the cutting blade 210 from the radially outer side, for example, and is positioned higher than the processing water jetting port 216 a of the processing water nozzle 216. The light emitting unit 40 can emit light of two wavelengths, and preferably emits light of a wavelength of 80 nm to 200 nm and light of a wavelength of 240 nm to 280 nm. The light emitting section 40 is more preferably capable of emitting light having a wavelength of 365 nm. The light-emitting portion 40 in this embodiment is a two-wavelength LED or a low-pressure mercury lamp, and can simultaneously emit ultraviolet light having a wavelength of 184.9 nm and ultraviolet light having a wavelength of 253.7 nm.

Hereinafter, each step of the processing method and the operation of the cutting device 2 when the processing method of the present invention is implemented using the cutting device 2 shown in FIG. 7 will be described step by step. The processed object W shown in FIG. 1 having a circular plate shape is, for example, a semiconductor wafer formed of SiC, which is a hard-to-cut material. On the front surface Wa of the processed object W, which faces the upper side in FIG. A plurality of elements D are formed in a grid-like region divided by a predetermined division line S. A cutting tape T1 having a larger diameter than the workpiece W is attached to the back surface Wb of the workpiece W. A circular frame F having a circular opening is attached to the outer peripheral area of the adhesive surface of the dicing tape T1, and the workpiece W is supported by the cyclic frame F through the dicing tape T1, and becomes a transparent loop. The status of the operation processing performed by the framework F. In addition, the shape and type of the workpiece W is not particularly limited, and may be appropriately changed according to the relationship with the dicing blade 210, and also includes a wafer formed of GaAS or GaN, or a wafer formed of a metal. Or the wafer with the metal electrode partially exposed on the back of the wafer.

(1) Holding step The workpiece W is placed on the holding surface 200 a of the holding table 20 with the dicing tape T1 side facing down. Then, the suction force generated by a suction source (not shown) is transmitted to the holding surface 200 a, and thereby the workpiece W is sucked and held by the holding table 20. The ring frame F is fixed by each fixing jig 204.

(2) Processing step The workpiece W held on the holding table 20 is fed in the -X direction by the cutting feed mechanism 22, and the calibration mechanism 25 is used to detect that the predetermined division line S of the cutting blade 210 should be cut in The coordinate position in the Y-axis direction. In addition, the indexing feed mechanism 23 drives the processing mechanism 21 in the Y-axis direction to perform alignment between the predetermined division line S to be cut and the cutting blade 210 in the Y-axis direction.

The cutting-in feed mechanism 24 lowers the processing mechanism 21 in the -Z direction. As shown in FIG. 9, positioning the processing mechanism 21 at, for example, the cutting blade 210 cuts through the back surface Wb of the workpiece W and reaches a predetermined height of the cutting tape T1. position. In addition, as the spindle 211 is rotationally driven by a motor (not shown), the cutting blade 210 rotates at a high speed in a clockwise direction when viewed from the -Y direction side, for example.

When the holding table 20 holding the workpiece W is further fed in the -X direction at a predetermined cutting feed speed, the cutting blade 210 rotating at a high speed will cut into the workpiece W, and will be cut along the predetermined dividing line S. The processed product W is cut. In the cutting process, the processing water nozzle 214 sprays processing water from the side of the cutting blade 210 to the contact portion of the cutting blade 210 and the workpiece W to cool and clean the contact portion.

With the start of the cutting process, the light-emitting portion 40 is turned on by the power source 41. The light-emitting portion 40 radiates, for example, ultraviolet light with a wavelength of 184.9 nm and a wavelength of 253.7 from the outer circumferential direction of the cutting blade 210 toward the processing surface of the rotating cutting blade 210. nm UV light.

In addition, the processing water nozzle 216 sprays processing water from the outer peripheral direction of the cutting blade 210 toward the processing surface of the cutting blade 210, so that the processing water is drawn into the processing surface of the rotating cutting blade 210 irradiated with light, and together with the cutting The blade 210 is pushed out toward the −X direction side along with machining chips and the like generated at the contact portion of the workpiece W, thereby cooling and cleaning the contact portion.

By irradiating the processing surface of the cutting blade 210 immediately before the processing water is sprayed from the processing water nozzle 216, ultraviolet light having a wavelength of 184.9 nm is absorbed, and oxygen molecules existing in the air between the front surface of the cutting blade 210 and the light emitting portion 40 are absorbed. Ultraviolet light generates oxygen atoms in the ground state. The generated oxygen atoms will bond with the surrounding oxygen molecules to generate ozone. In addition, the ultraviolet light having a wavelength of 184.9 nm cuts off intermolecular bonds and interatomic bonds caused by cutting debris attached to the processing surface of the cutting blade 210 into an excited state, thereby decomposing organic pollution. In addition, the generated ozone absorbs ultraviolet light with a wavelength of 253.7 nm, thereby generating active oxygen in an excited state. Since the generated active oxygen or ozone has high oxidizing power, it will be bonded with carbon or hydrogen generated on the processing surface of the cutting blade 210, and hydroxyl groups, aldehyde groups, and carboxyl groups will be formed on the processing surface of the cutting blade 210. Large polar hydrophilic group. As a result, the cutting blade 210 will be hydrophilized, and the processing water will not easily become water droplets on the processing surface of the cutting blade 210, and the processing water will easily spread into a water film shape on the processing surface of the cutting blade 210.

The hydrophilized cutting blade 210 is cut into the back surface Wb of the workpiece W along with a large amount of processing water sprayed from the processing water nozzle 216. More processing water enters the contact portion between the back surface Wb of the workpiece W and the processing surface of the cutting blade 210, thereby suppressing the generation of frictional heat that occurs at the contact portion.

When the workpiece W advances in the -X direction to a predetermined position in the X-axis direction of the cutting blade 210 after the cutting is scheduled to be performed, the cutting feed of the workpiece W in the -X direction is temporarily stopped, and the cutting blade is stopped. 210 is separated from the workpiece W, and the holding table 20 is fed in the + X direction to return to the original position. Then, the cutting blade 210 is fed one by one in the Y-axis direction at intervals of the adjacent divided scheduled lines S and sequentially performs the same cutting, thereby cutting all the divided scheduled lines S in the same direction. In addition, when the same cutting is performed after the holding table 20 is rotated by 90 degrees, all of the planned division lines S are fully and horizontally cut.

The method for processing a workpiece according to the present invention includes a holding step for holding the workpiece W with a holding table 20 having a holding surface 200a for holding the workpiece W; and a processing step for including a processing grindstone after the holding step is performed. That is, the processing mechanism 21 of the cutting blade 210 processes the workpiece W. The processing grindstone is made of a ceramic binder in combination with abrasive grains. In the processing step, processing water is supplied to the workpiece W, and from The light irradiation mechanism 4 irradiates the processing surface of the cutting blade 210 with light of a predetermined wavelength, and thereby, due to the hydrophilization of the cutting blade 210, more processing water enters the back surface Wb of the workpiece W and the processing surface of the cutting blade 210. The contact part can suppress the generation of frictional heat generated at the contact part, thereby suppressing excessive wear of the cutting blade 210, and can prevent the processing quality of the wafer from being deteriorated due to the increase in processing heat, even if it is damaged. The processed object W is a wafer formed of a hard-to-cut material, and can be cut smoothly. In addition, cutting water generated at the contact portion between the back surface Wb of the workpiece W and the processing surface of the cutting blade 210 can be efficiently removed by the processing water.

1‧‧‧Grinding device

10‧‧‧ base

11‧‧‧ pillar

12‧‧‧ import agency

2‧‧‧ cutting device

2A‧‧‧ abutment

20‧‧‧holding table

200‧‧‧ Adsorption Department

200a‧‧‧ holding surface

201‧‧‧Frame

202‧‧‧Rotating mechanism

204‧‧‧Fixed fixture

21‧‧‧Processing Agency

210‧‧‧ cutting blade

211‧‧‧ Spindle

212‧‧‧shell

213‧‧‧Support block

213a‧‧‧Adjustment screw

213b‧‧‧Supply tube

213c‧‧‧Fog cover

214‧‧‧Processing Water Nozzle

215‧‧‧Processed water block

215a‧‧‧Adjustment screw

215b‧‧‧Supply tube

216‧‧‧Processing Water Nozzle

216a‧‧‧Processing water jet

217‧‧‧Fixed nut

218‧‧‧ Loading flange

219‧‧‧Blade cover

22‧‧‧ cutting feed mechanism

220‧‧‧ball screw

221‧‧‧rail

222‧‧‧Motor

223‧‧‧Movable plate

23‧‧‧ indexing feed mechanism

230‧‧‧ball screw

231‧‧‧rail

232‧‧‧Motor

233‧‧‧Mobile

234‧‧‧Column

24‧‧‧cut into the feed mechanism

240‧‧‧ Ball Screw

241‧‧‧rail

242‧‧‧ Motor

243‧‧‧Supporting members

25‧‧‧ Calibration Agency

250‧‧‧ Calibration Camera

30‧‧‧holding table

300‧‧‧ Adsorption Department

300a‧‧‧ holding surface

301‧‧‧Frame

31‧‧‧ cover

31a‧‧‧ Retractable cover

4‧‧‧light irradiation mechanism

40‧‧‧Lighting Department

41‧‧‧ Power

5‧‧‧Grinding feed mechanism

50‧‧‧ball screw

51‧‧‧rail

52‧‧‧Motor

53‧‧‧Elevating plate

54‧‧‧ bracket

7‧‧‧ processing agency

70‧‧‧rotation axis

70a‧‧‧flow

71‧‧‧shell

72‧‧‧ Motor

73‧‧‧base

73b‧‧‧flow

74‧‧‧Grinding Wheel

74a‧‧‧millstone

74b‧‧‧ round abutment

74d‧‧‧jet port

8‧‧‧Processed water supply agency

80‧‧‧Processed water

81‧‧‧Piping

82‧‧‧adjusting valve

9‧‧‧ light irradiation mechanism

90‧‧‧ Taiwan

91‧‧‧Lighting Department

92‧‧‧Washing water supply department

920‧‧‧washing water nozzle

920a‧‧‧jet port

93‧‧‧ Cover

A‧‧‧Loading area

B‧‧‧Grinding area

D‧‧‧Element

E‧‧‧Processing area

F‧‧‧ ring frame

G1‧‧‧ Graphics

G2‧‧‧ Graphics

P1‧‧‧Drawing point

S‧‧‧ divided scheduled line

T‧‧‧protective tape

T1‧‧‧Cutting Tape

W‧‧‧Processed

Wa‧‧‧Front of the processed object

Wb‧‧‧ The back of the object

X, Z‧‧‧ axis directions

+ X, -X, + Y, -Y, + Z, -Z‧‧‧ directions

FIG. 1 is a perspective view showing an example of a grinding apparatus. 2 is a perspective view showing an example of a positional relationship between a grinding mechanism, a holding table, and a light irradiation mechanism. FIG. 3 is an end view showing a state in which a workpiece to be held on a holding table is ground with a grinding stone. FIG. 4 (A) is an explanatory diagram when the rotational trajectory of the grinding wheel during the grinding process, the processing area of the workpiece formed by the grinding stone, and the positional relationship of the light irradiation mechanism are viewed from above. FIG. 4 (B) is an explanatory diagram when the working grindstone which has just been irradiated with light on the working surface is cut into the object, viewed from the side. 5 is an end view partially showing a state in which washing water is supplied to a cover on a light emitting portion during a grinding process. FIG. 6 is a tracing plot showing the effect of irradiating ultraviolet light with a wavelength of 365 nm on the processing surface of the processing grindstone during grinding obtained in Experiment 1. FIG. 7 is a perspective view showing an example of a cutting device. FIG. 8 is a cross-sectional view showing a holding table and a cutting mechanism holding a workpiece. 9 is a cross-sectional view showing a state in which a workpiece to be held on a holding table is cut by a cutting mechanism.

Claims (3)

A processing method is a method for processing a workpiece, comprising: a holding step for holding the workpiece on a holding table having a holding surface for holding the workpiece; and a processing step for carrying a grinding stone after the holding step is performed A processing mechanism for processing a workpiece, the processing grindstone is made of a ceramic binder in combination with abrasive particles, and in this processing step, processing water is supplied to the workpiece, and the processing grindstone is supplied from a light irradiation mechanism The machined surface is irradiated with light of a predetermined wavelength. The processing method according to claim 1, wherein the processing mechanism has a cutting blade provided with the processing grindstone, and in the processing step, the workpiece is cut with the cutting blade. The processing method according to claim 1, wherein the processing mechanism includes a grinding wheel provided with the grinding stone, and in the processing step, the workpiece is ground with the grinding wheel.