JP7324889B2 - chamfering system - Google Patents

Description

The present invention relates to a chamfering system having a plurality of wafer chamfering machines for chamfering the periphery of wafers of various materials such as silicon, sapphire, compound, and glass, particularly semiconductor wafers and glass panels, and a truing device used therefor. It is suitable for grinding in which the whetstone is inclined with respect to the plate-shaped workpiece.

In recent years, there has been a strong demand for improved quality of wafers, and the processing state of the wafer end face (edge portion) has been emphasized. 2. Description of the Related Art Semiconductor wafers such as silicon wafers used for manufacturing semiconductor devices are chamfered by grinding the edges and mirror-beveled by polishing in order to prevent chipping due to handling. In other words, in the semiconductor manufacturing process, from wafer manufacturing to device manufacturing, quality improvement of edge characteristics is an essential process.

Silicon and other materials are hard and brittle, and if the edge of the wafer remains sharp during slicing, it can easily break or chip during handling such as transportation and positioning in subsequent processing steps, and the fragments can damage or contaminate the wafer surface. or In order to prevent this, the end face of the cut wafer is chamfered with a diamond-coated chamfering whetstone.

In addition, masking printing and sensor electrode formation are performed on glass substrates to reduce the thickness and weight of smartphones and tablets, and then the substrates are cut. In addition, the quality of chamfering, the roughness of the processed surface, the generation of microcracks, etc., directly affect the strength of the edge surface of the glass substrate.

Furthermore, in normal grinding, the chamfered portion is ground with the main surface of the wafer perpendicular to the rotating shaft of the resin grindstone. Therefore, it is known to perform so-called helical grinding, in which, for example, a resin bond grindstone (resin grindstone) is tilted with respect to the wafer to grind the chamfered portion of the wafer.

In particular, in order to improve the roughness accuracy of the chamfered surface and not to reduce the polishing efficiency, in the chamfering method of the semiconductor wafer for polishing the periphery of the semiconductor wafer, the rotating shaft of the grindstone is tilted in the tangential direction of the outer periphery of the semiconductor wafer. It is known to tilt the abrasive grain motion direction of the grindstone with respect to the polishing surface of the semiconductor wafer by polishing the peripheral edge.

In addition, when helical grinding is performed, not only does processing strain on the chamfered portion be reduced compared to normal grinding, but also the chamfered portion of the wafer and the grindstone come into surface contact, increasing the contact area and improving the surface roughness of the chamfered portion. effect is obtained.

Wafer chamfering machines are used in mass production lines, and usually one machine processes wafers contained in 2 to 12 cassettes. Therefore, one wafer chamfering machine is capable of processing two wafers, and is often used as a biaxial chamfering machine having two rotating shafts of grinding wheels. Furthermore, in an actual mass production line, a plurality of wafer chamfering machines may be installed, and the grinding unit may be a chamfering system that performs processing up to 50 axes.

Furthermore, there is a predetermined standard for the wafers to be chamfered by the wafer chamfering machine, and the wafer chamfering machine chamfers the wafer by setting processing conditions so as to meet the standard. Usually, the outer shape of a chamfered wafer is measured to check whether the wafer has been chamfered according to the standard.

JP-A-5-152259 JP 2017-159421 A

Among the above-described prior arts, those disclosed in Patent Documents 1 and 2 perform truing of a grindstone for helical grinding in each wafer chamfering machine. That is, the cross-sectional shape of the master groove of the master grindstone is transferred to the cross-sectional shape of the outer peripheral portion of the tool provided in each wafer chamfering machine, and the transferred tool is used to make the grindstone whose rotation axis is inclined in the tangential direction of the wafer W. groove shape.

Therefore, when a plurality of wafer chamfering machines are installed, even if processing conditions are set accurately for each wafer chamfering machine, wafers of the same shape are not always chamfered by each wafer chamfering machine. Strictly speaking, it may be machined into a different shape depending on the inclination of the rotating shaft, the degree of wear, the state of supply of grinding fluid, and the like.

Specifically, if the inclination angle of the rotation axis of the grinding wheel is different for each wafer chamfering machine, there is a possibility that the symmetry of the cross-sectional shape of the wafer end face will be different. In order to prevent this, it has been necessary to adjust the processing conditions of each wafer chamfering machine, especially the rotation axis of the grinding wheel, in the inspection process after processing.
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art. To comprehensively manage the shape accuracy of a wafer end surface processed by a chamfering machine so as to fall within a predetermined range.

In particular, in helical grinding, the influence of the rotating shaft on the cross-sectional shape of the wafer edge is reduced, maintaining uniform quality even when performing multiple chamfering processes, and maintaining high productivity by reducing adjustment processes. to do.

In order to achieve the above objects, the present invention has the following features.

[1] A chamfering system for chamfering the outer periphery of a wafer using a grinding wheel, comprising a grindstone processing machine having a master grindstone provided with a plurality of master grooves, and a controller, wherein the controller comprises The master groove to be used for correcting the grinding wheel is determined based on the measured value of the end face shape of the wafer, and the grindstone processing machine uses the determined master groove to form the grinding groove of the grinding wheel. , chamfering system.
[2] The controller according to [1], wherein the measured value of the end face shape is converted into grindstone shape data, and the master groove to be used is determined based on the difference between the grindstone shape data and a reference value. chamfering system.
[3] The controller converts the measured value of the end face shape into inter-axis difference data indicating the difference between the inclination of the rotation axis of the grinding wheel and the reference value, and based on the inter-axis difference data, converts the above-mentioned The chamfering system according to [1] or [2], which determines a master groove.
[4] The controller determines the master grooves to be used based on the end surface shape measured at a predetermined time or every predetermined number of processed wafers, and the grindstone machine determines the master grooves thus determined. The chamfering system according to any one of [1] to [3], wherein the grinding groove is formed using

Another aspect of the present invention is a chamfering system having a plurality of wafer chamfering machines for chamfering the outer periphery of a wafer using a grinding wheel, wherein a wafer chamfering line in which a plurality of the wafer chamfering machines are installed; A wafer shape measuring machine that measures the edge shape of the wafer processed by the wafer chamfering machine, a controller that determines whether or not the grinding wheel needs to be corrected based on the values measured by the wafer shape measuring machine, and a plurality of master grooves. and a grindstone processing machine capable of forming a grinding groove of the grinding wheel with the master groove, wherein the controller determines a plurality of values based on the values measured by the wafer shape measuring machine. Any one of the master grooves is determined from the master grooves, and the grinding machine forms the grinding grooves using the master grooves determined by the controller.

Further, in the above, the controller converts the values measured by the wafer shape measuring machine as grindstone shape data, and selects one of the master grooves from the plurality of master grooves based on the difference between the grindstone shape data and a reference value. It is desirable to make a master groove determination.

Further, in the above, the controller converts the value measured by the wafer shape measuring machine into inter-axis difference data indicating the difference between the inclination of the rotation axis of the grinding wheel and a reference value, and converts the value into the inter-axis difference data It is desirable to determine any one of the master grooves from the plurality of master grooves based on the above.

Furthermore, in the above, it is desirable that the grindstone processing machine can be used in common by each of the wafer chamfering machines in the wafer chamfering line.

Further, in the above, the end face shape of the wafer is measured by the wafer shape measuring machine for all the wafer chamfering machines installed on the wafer chamfering line, the master groove is determined by the controller, and the grindstone is It is desirable to form the ground grooves using the master grooves determined by the processing machine.

Furthermore, in the above, it is preferable that the master grooves determined for each of the wafer chamfering machines be stored in the controller as a database.

Further, in the above, the end surface shape of the wafer is measured by the wafer shape measuring machine every predetermined time or every predetermined number of wafers to be processed, and the master groove is determined by the controller, and the grinding stone machine is used. Preferably, the ground groove is formed using the master groove determined by.

Further, in the above, when the total number of processed wafers on the wafer chamfering line reaches a predetermined value, the end face shape of the wafer is measured by the wafer shape measuring machine, and the master groove is determined by the controller. and forming the ground grooves using the master grooves determined by the grinding machine.

Further, the present invention provides a truing apparatus for forming grinding grooves by truing a grinding wheel for chamfering a wafer, wherein a controller for determining whether or not the grinding wheel needs to be corrected from a value obtained by measuring the end face shape of the wafer; and a grindstone processing machine that is provided with a master grindstone provided with a master groove of and capable of forming the grinding groove by the master groove, wherein the controller controls the plurality of the Any one of the master grooves is determined from the master grooves, and the grinding machine forms the grinding grooves using the master grooves determined by the controller.

Further, in the above-mentioned device, it is desirable to form the grinding grooves using a tool that transfers the shape of the master groove to the outer peripheral portion and the tool.

According to the present invention, the edge shape of the wafer processed by each wafer chamfering machine is measured, and from the measured value, the controller is provided to determine whether or not the grinding wheel needs to be corrected. Determine which master groove. Since the determined master grooves are used to form the grinding grooves of the grinding wheel, even if the setting of the rotation axis of the grinding wheel is different for each wafer chamfering machine, the shape accuracy of the wafer is kept within a predetermined range. be able to. Therefore, even when a large number of chamfering processes are performed, it is possible to maintain uniform quality, reduce adjustment processes, and maintain high productivity.

1 is a block diagram showing the configuration of a chamfering system according to an embodiment of the present invention; FIG. Front view showing main parts of a wafer chamfering machine in one embodiment The side view which expanded the portion of the grinding wheel in one embodiment. Sectional view showing the relationship between the grinding wheel and the wafer W in one embodiment A sectional view showing the shape of the wafer W after processing in one embodiment. 3 is a flow chart showing a wafer shape accuracy management and correction method in a wafer chamfering line in one embodiment. Side view showing truing operation in one embodiment Sectional drawing of the master whetstone in one embodiment Cross-sectional view showing a master groove in one embodiment Table showing truing test results as an example

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a chamfering system according to one embodiment of the present invention. Reference numeral 1 denotes a wafer chamfering line in which a plurality of wafer chamfering machines 10 are installed. The wafer chamfering line 1 includes wafer chamfering machines 10-1, 10-2, 10-3, . A wafer shape measuring machine 2 measures the end surface shape of the wafer W processed by the wafer chamfering machines 10-1, 10-2, 10-3, . . .

A truing device 3 has a controller 3-1 and a grindstone processing machine 3-2. The truing device 3 receives the results of measurement by the wafer shape measuring machine 2 and converts them into grindstone shape data. Based on the converted grindstone shape data, the controller 3-1 determines whether or not the grinding wheel needs to be corrected, and a master groove group 143 for correcting the grinding wheel 55 (FIG. 2) based on the difference between the grindstone shape data and the reference value. One of the master grooves 143-1 . . . (FIGS. 8 and 9) is determined. Using the determined master grooves 143-1 .

FIG. 2 is a front view showing the main parts of the wafer chamfering machine. The wafer chamfering machine 10 comprises a wafer feeding unit 20, a grindstone rotating unit 50, a wafer supply/storage unit (not shown), a wafer cleaning/drying unit, a wafer conveying means, a controller for controlling the operations of each part of the wafer chamfering machine, and the like. there is

The wafer feed unit 20 includes an X-axis base 21 placed on the body base 11, two X-axis guide rails 22, 22, four X-axis linear guides 23, 23, . It has an X table 24 that is moved in the X direction in the figure by an X-axis drive mechanism 25 composed of.

The X table 24 has two Y-axis guide rails 26, 26, four Y-axis linear guides 27, 27, . Y table 28 is incorporated.

The Y table 28 is guided by two Z-axis guide rails 29, 29 and four Z-axis linear guides (not shown), and is moved in the Z direction in the figure by a Z-axis drive mechanism 30 consisting of a ball screw and a stepping motor. A Z table 31 is incorporated.

A .theta.-axis motor 32 and a .theta.-spindle 33 are incorporated in the Z table 31, and a wafer table 34 is attached to the .theta. The wafer table 34 is rotated in the .theta. direction around the wafer table rotation axis CW.

By this wafer feeding unit 20, the wafer W and the tool 41 are rotated in the .theta. direction and moved in the X, Y and Z directions.

The grindstone rotation unit 50 has an outer circumference rough grinding grindstone 52 attached thereto, an outer circumference grindstone spindle 51 driven to rotate about its axis by an outer circumference grindstone motor (not shown), and an outer circumference fine grinding attached to a turntable 53 disposed above. It has a spindle 54 and an outer circumference fine-grinding motor 56 .

FIG. 3 is an enlarged side view of a portion of the grinding wheel 55. The grinding wheel 55, which is a chamfering wheel for finish-grinding the outer periphery of the wafer W, is attached to the outer periphery precision grinding spindle 54. As shown in FIG. The peripheral fine grinding spindle 54 performs the finishing process of chamfering the outer periphery of the wafer W in a state of being inclined with respect to the rotation axis R of the wafer W by 3 to 20 degrees. As a result, helical grinding is performed, and although weak grinding marks are generated in the oblique direction on the chamfered portion of the wafer W, the effect of improving the surface roughness of the chamfered portion compared to normal grinding is obtained.

The wafer processing process is performed in the order of slicing→chamfering→lapping→etching→donor killer→precision chamfering, and various types of cleaning are used between the steps to remove dirt. Silicon and other materials are hard and brittle, and if the edge of the wafer remains sharp during slicing, it can easily break or chip during handling such as transportation and positioning in subsequent processing steps, and the fragments can damage or contaminate the wafer surface. or In order to prevent this, in the chamfering step, the end face of the cut wafer is chamfered with a diamond-coated chamfering grindstone.

The grinding wheel 55 is made of, for example, metal powder such as Fe, Cr, Cu, etc. as a main component, mixed with diamond abrasive grains, and molded. As for the material, for example, the main component is phenol resin, epoxy resin, polyimide resin, polystyrene resin, polyethylene resin or the like, and it is desirable to mix and mold diamond abrasive grains or cubic boron nitride abrasive grains.

The grinding wheel 55 is a resin-bonded diamond wheel with a diameter of 50 mm and a grain size of #3000. The peripheral fine grinding spindle 54 is a built-in motor-driven spindle using an air bearing, and is rotated at a rotational speed of 35,000 rpm.

FIG. 4 is a sectional view showing the relationship between the grinding wheel 55 and the wafer W, with the rotation axis R tilted. The grinding grooves of the grinding wheel 55 are composed of an upper inclined surface 55u, a central portion 55C, and a lower inclined surface 55d. The upper and lower ends (regions of Tu and Td) of the processed wafer W, which are the upper and lower portions, have streaks in different directions compared to the central portion C due to the slope of the streaks. Then, the effect of helical grinding is sufficiently obtained, and the processing strain and surface roughness are improved to the same extent as in the central portion.

FIG. 5 is a sectional view showing the shape of the wafer W after processing. Strictly speaking, the inclination of the rotation axis R differs for each of the wafer chamfering machines 10-1, 10-2, 10-3, . . . in FIG. is set. Further, even if the inclination of the rotation axis R is the same in the wafer chamfering machines 10-1, 10-2, 10-3, .

The inclination of the grinding wheel 55 with respect to the rotation axis R can also be regarded as the difference between the axes. In addition to the axial difference, the inclination of the wafer table 34 for fixing the wafer W, the fixed state of the wafer W, the grinding resistance, the wear condition, the supply condition of the grinding liquid, etc. -3…Due to the difference in each machine number, it affects the shape accuracy of the machined surface.

FIG. 5 is an example of a cross-sectional view showing the shape of the wafer W after processing. This is an example in which A2 is 290 μm, B2 is 240 μm, and θ2 is 42 degrees. The values of A1, B1, .theta.1, A2, B2, .theta.2 are different for each of the wafer chamfering machines 10-1, 10-2, 10-3, .

FIG. 5(b) is an example of a cross-sectional view showing the shape of the wafer W after processing. , B2 is 190 μm, and θ2 is 40 degrees. From the above, it is important to adjust various conditions, especially the inclination of the rotation axis, for each of the wafer chamfering machines 10-1, 10-2, 10-3, . . .

FIG. 6 is a flowchart showing a method for controlling and correcting the shape accuracy of a wafer in a wafer chamfering line in which a plurality of wafer chamfering machines 10 are installed. It corrects for the effects of Description will also be made with reference to the block diagram of FIG.

In step 1, the wafers W processed by the respective wafer chamfering machines 10-1, 10-2, 10-3, . The measured data is input to the controller 3-1 of the truing device 3.

In the controller 3-1, as step 2, based on the data as shown in FIG. It converts as inter-axis difference data that indicates the difference from the value. In step 3, the shape of the grinding wheel 55 is corrected based on the value obtained in step 2 and the data on the difference between the axes, that is, it is determined whether or not truing is necessary.

FIG. 7 is a side view showing the truing operation performed by the grindstone processing machine 3-2 of the truing device 3. FIG. A truing grindstone 141 (hereinafter referred to as a truing tool 141) used for truing the grinding wheel 55 for finish chamfering the peripheral edge of the wafer W is mounted on the master table 134 of the grindstone processing machine 3-2 and rotated by a master motor (not shown). be. The grinding wheel processing machine 3-2 is capable of truing the grinding wheels 55 used in all the wafer chamfering machines 10-1, 10-2, 10-3, . . .

FIG. 8 is a cross-sectional view of the master grindstone 142 provided in the grindstone processing machine 3-2. Prior to truing the grinding wheel 55, the outer peripheral portion of the truer 141 is processed by the master grindstone 142, and the shape of one of the master grooves 143 provided on the outer periphery of the master grindstone 142 is transferred to the outer peripheral portion of the truer 141. be.

FIG. 9 is a sectional view showing the master groove group 143, in which a plurality of grooves are provided corresponding to the difference data between the shafts, such as master grooves 143-1, 143-2, . . . 143-8. For example, when the reference value of the inclination of the rotation axis R shown in FIG. 3 is 15 degrees, the master groove 143-1 has a shape corresponding to 15.0 degrees, 143-3 is 16.0 degrees, master groove 143-4 is 16.5 degrees, master groove 143-5 is 17.0 degrees, master groove 143-6 is 14.5 degrees, and master groove 143-7 is 14.5 degrees. The correction range is set so that the reference value is plus and minus with respect to 15 degrees, such as 0 degrees and 13.5 degrees for the master groove 143-8. The same applies when the reference value is 18 degrees.

In step 4, for the wafer chamfering machines 10-1, 10-2, 10-3, . , which one of the master grooves 143-1, 143-2, . . .

In step 5, the outer peripheral portion of the truer 141 is machined using the master groove determined in step 4, and the determined cross-sectional shape of the master groove is transferred to the cross-sectional shape of the outer peripheral portion of the truer 141. FIG. Then, the grinding groove of the grinding wheel 55 is formed by using the tool 141 to which the cross-sectional shape of the determined master groove is transferred to the outer peripheral portion. In this processing, the master grindstone 142 is rotated at a rotational speed of 8,000 rpm, and the master groove determined by moving the tool 141 in the Z direction in FIG. 7 is performed.

The processing conditions of the grindstone processing machine 3-2 are determined so that it can be commonly used in a wafer chamfering line in which a plurality of wafer chamfering machines 10 are installed. Therefore, since the grinding wheel 55 (FIG. 2) of each wafer chamfering machine 10-1, 10-2, 10-3, . , 10-2, 10-3, . Further, the shape precision is not affected by the different processing conditions of the wafer chamfering machines 10-1, 10-2, 10-3, .

A material that can be processed by the master grindstone 142 and that can be ground by the grinding grindstone 55 is adopted as the material of the truer 141 . For example, it is preferable that abrasive grains made of silicon carbide are bonded with a phenolic resin, if necessary, with a filler or the like added, and this is formed into a disc-shaped tool 141 .

In addition, the tool 141 may be a disk-shaped GC (Green silicon carbide) grindstone or a WA (White fused aluminum) grindstone having an outer diameter equal to or smaller than that of the wafer W to be processed and having the same thickness, and the grain size of the grindstone is #320. Good degree.

In step 6, the wafer W is processed using the grinding wheel 55 on which the grinding grooves are formed in step 5. As shown in FIG. The processed wafer W returns to step 1 and the end face shape and the like are measured again. Note that the shape measurement in step 1 is performed for all the wafer chamfering machines 10-1, 10-2, and 10 at the initial stage of installation of a wafer chamfering line in which a plurality of wafer chamfering machines 10 are installed. It is desirable to carry out the processes from step 1 to step 6 on the wafer W processed in -3.

Also, at this time, in step 4, which one of the master grooves 143-1, 143-2, . . . are made into a database and stored in the controller 3-1. This shortens the time required for the process of correcting the grinding wheel and facilitates quality control.

FIG. 10 shows the result of a truing test in which the shape angle of the wafer W processed by the trued grinding wheel 55 (FIG. 7) was actually measured. In the test, the master grooves of the master groove group 143 (FIG. 8) were of five types, grooves 1 to 5, and four wafer chamfering machines 10-1, 10-2, 10-3, . A total of 8 axes from A to H were used. In FIG. 10, the vertical axis represents grooves 1 to 5, which are master grooves, and the horizontal axis represents machining axes A to H. In FIG. The groove 1 was 17.6 degrees, the groove 2 was 17.8 degrees, the groove 3 was 18.0 degrees, the groove 4 was 18.2 degrees, and the groove 5 was 18.4 degrees. Also, the reference value for the inclination of the rotation axis R shown in FIG. 3 is 18 degrees. The results are obtained by processing the wafer W with the grooves 1 to 5 for each processing axis and measuring the shape.

It is optimal to select one of the grooves 1 to 5 that has the target shape of 18.0 degrees for each machining axis. As can be seen from FIG. 10, machining axis A has groove 2, machining axis B has groove 3, machining axis C has groove 4 (or groove 5), machining axis D has groove 3, machining axis E has groove 1, and machining axis F. Groove 2 is optimum for , groove 2 is optimum for machining axis G, and groove 2 is optimum for machining axis H. Therefore, in this test example, the relationship between each machining axis and the optimum groove is made into a database and stored in the controller 3-1 (FIG. 1).

When a wafer chamfering line is installed and production is being carried out, the shape measurement of step 1 is performed on the wafer chamfering machines 10-1, 10-2, 10 at any time, at a predetermined time, or at each predetermined number of processed wafers W. -3 Perform for the wafer W processed in . . .

At this time, when the total time for all the wafer chamfering machines 10-1, 10-2, 10-3, . When one of 10-1, 10-2, 10-3, .

However, when any one of the wafer chamfering machines 10-1, 10-2, 10-3, . Performing step 1 is more efficient than performing step 1 for all the wafer chamfering machines 10-1, 10-2, 10-3, .

In any case, steps 1 to 6 are not performed for each individual wafer chamfering machine 10-1, 10-2, 10-3, . A truing device 3 is provided exclusively. As a result, differences in the processing conditions of each wafer chamfering machine are corrected intensively, so that it is possible to comprehensively manage the shape accuracy of the wafers in the entire mass production line. Although helical grinding is performed by tilting the rotation axis of the grinding wheel 55, the entire mass production line can be similarly processed by performing corrections similar to steps 1 to 6 in normal end face grinding in which the rotation axis is not tilted. This makes it possible to comprehensively manage the shape accuracy of wafers and achieve uniform quality.

W... Wafer, R... Rotary axis, 1... Wafer chamfering line, 2... Wafer shape measuring machine, 3... Truing device, 3-1... Controller, 3-2... Grinding machine, 10, 10-1, 10-2 , 10-3 Wafer chamfering machine 11 Main body base 20 Wafer feeding unit 21 X-axis base 22 X-axis guide rail 23 X-axis linear guide 24 X-table 25 X-axis drive Mechanism 26 Y-axis guide rail 27 Y-axis linear guide 28 Y table 29 Z-axis guide rail 30 Z-axis drive mechanism 31 Z table 32 θ-axis motor 33 θ-spindle , 34... Wafer table, 41... Tooler, 50... Grindstone rotation unit, 51... Peripheral grindstone spindle, 52... Periphery rough grinding wheel, 53... Turntable, 54... Peripheral fine grinding spindle, 55... Grinding wheel, 55u... Top slope , 55C... central portion, 55d... lower surface slope, 56... perimeter precision grinding motor, 141... truing whetstone (truer), 134... master table, 142... master whetstone, 143... master groove group, 143-1, 143-2, 143-3, 143-4, 143-5, 143-6, 143-7, 143-8... master grooves

Claims (4)

In a chamfering system that chamfers the outer periphery of a wafer using a grinding wheel,
A grindstone processing machine having a master grindstone provided with a plurality of master grooves of different shapes , and a controller,
The controller determines the master groove to be used for correction of the grinding wheel based on the measured value of the end face shape of the wafer processed using the grinding wheel,
The chamfering system, wherein the grindstone processing machine uses the determined master groove to form a grinding groove of the grinding wheel. 2. The chamfering system according to claim 1, wherein the controller converts the measured value of the end face shape into grindstone shape data, and determines the master groove to be used based on the difference between the grindstone shape data and a reference value. . The controller converts the measured value of the end face shape into axis difference data indicating the difference between the inclination of the rotation axis of the grinding wheel and a reference value, and selects the master groove to be used based on the axis difference data. 3. The chamfering system according to claim 1 or 2, which determines. The controller determines the master grooves to be used based on the end surface shape measured at a predetermined time or every predetermined number of processed wafers, and the grinding machine uses the determined master grooves. 4. The chamfering system according to any one of claims 1 to 3, wherein the grinding groove is formed.