Truing device and method of grinding stone

Abstract

To provide a truing method and device of a grinding stone which not only realize the shape of the grinding stone with complex groove shapes with high accuracy and high quality, but also shorten the time required for truing even for a hard-to-process material.SOLUTION: A truing method of a grinding stone 16 used for a chamfering device for a wafer W includes: performing truing at a high speed by leaving a processing portion of truing as rough processing such that a grinding stone 16 becomes a rough grinding target shape with a rough grinding truer 10-1; and performing truing as precise processing such that the grinding stone becomes a precise grinding target shape with a precise grinding truer 10-2 with the greater mesh of the grindstone than the rough grinding truer 10-1 when the grinding stone 16 falls within an allowable range of the rough grinding target shape. The face angle of the rough grinding truer 10-1 is made to be smaller by 1 to 3 degrees than the face angle θ which is the design value of the wafer W.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for truing a grinding wheel having a groove shape used in a chamfering device for the edge surface of a semiconductor wafer. [Background technology]

[0002] In recent years, the production of semiconductor wafers and other products has been increasing in a wide variety of small quantities. For the grinding wheels with groove shapes used in the chamfering of wafers, there is an increasing demand for high precision, shape modification, and high speed for the purpose of the wide variety of small quantity production, improvement of wafer quality, and improvement of yield.

[0003] In addition, semiconductors using materials with a large ultra-wide band gap (UWBG) and strong bonds between the atoms that make up the crystal, such as SiC (silicon carbide), GaN (gallium nitride), gallium oxide, AlGaN, and diamond, are expected to be smaller than silicon semiconductors, have low power consumption, are highly efficient power elements, high frequency elements, and have excellent radiation resistance, and are being put into practical use. However, UWBG materials such as 4H-SiC are difficult to process, so there is a strong demand for high precision and quality improvements in the groove shape of grinding wheels.

[0004] Chamfering in the manufacturing process of semiconductor raw material wafers requires truing (grinding) a grinding wheel (precision grinding) with a truer, precision grinding the wafer, measuring the edge shape of the wafer after grinding, and repeating this process until the wafer has the desired shape. Therefore, truing of the grinding wheel is required to be performed particularly quickly and with high precision.

[0005] Also, in the finishing process of the outer peripheral chamfer of semiconductor wafers, it is known to use so-called helical grinding, in which the grinding wheel is tilted with respect to the wafer to grind the chamfered portion in order to prevent the generation of grinding marks in the circumferential direction.However, helical grinding requires delicate adjustments regarding the formation of the shape by truing the grinding wheel (the processed surface of the grinding wheel after truing is a three-dimensional shape that is not axially symmetrical with respect to the rotation axis (of the grinding wheel)), which takes time and requires a skilled dedicated person.

[0006] Patent Document 1 describes a method for truing for helical grinding in which a truer is used to form grooves, in which the truer is used to process the upper or lower part of the groove formed in the grinding wheel in order to improve the transfer rate and machinability as well as the accuracy of the groove formed by the truer, and then repeats lowering or raising the truer in the thickness direction relative to the grinding wheel.

[0007] Truing using laser light is also known, and Patent Document 2 describes truing using laser light, explaining that an ultrashort pulse laser such as a femtosecond laser is used to achieve high processing accuracy with minimal thermal impact on the tool being formed, and that truing is performed within a specified range both before and after the focal point of the laser light in the direction of travel. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2022-325 [Patent Document 2] JP 2015-98041 A Summary of the Invention [Problem to be solved by the invention]

[0009] In the above-mentioned conventional technology, the one described in Patent Document 1 requires adjustments by a skilled, dedicated person to the movement of the truer when truing the grinding wheel used for chamfering, and it takes time to repeat the process. In addition, with materials such as SiC that are difficult to process, it takes time to process them, it is difficult to form the desired shape, and the grinding wheel wears out quickly, so it is difficult to say that the cost of grinding can be sufficiently reduced.

[0010] In addition, in the method described in Patent Document 2, it is difficult to widen the irradiation range, and the area that can be trued at one time is small, so it is not possible to true the entire grinding wheel, and no consideration is given to improving the precision of the overall shape of a grinding wheel having a groove shape.

[0011] The object of the present invention is to solve the problems of the conventional technology described above, and to provide an efficient method and apparatus for truing a grinding wheel, which not only shapes a grinding wheel having a complex groove shape with high precision and quality, but also shortens the time required for truing even for difficult-to-process materials. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention is configured as follows. [1] A truing device for a grinding wheel used in a wafer chamfering device, comprising: a truer including a rough grinding truer and a fine grinding truer arranged coaxially with a rotation axis of the rough grinding truer and having a finer mesh than the rough grinding truer; a first sensor that detects a first position corresponding to at least one of the rough grinding truer and the fine grinding truer in a Z direction along the rotation axis; a second sensor that detects a second position of the grinding wheel in the Z direction; and a control unit that adjusts the positions of the truer and the grinding wheel in the Z direction based on the first position and the second position. [2] The grinding wheel truing device according to [1], wherein the truer is characterized in that the rough grinding truer and the fine grinding truer are connected in the Z direction. [3] The grinding wheel truing device described in [2], further comprising a chuck table for fixing the truer, and the first sensor detects the first position of the chuck table. [4] The truing device for a grinding wheel described in [3], characterized in that the chuck table has a first conductor or a first magnetic material, the grinding wheel has a second conductor or a second magnetic material, and the first sensor and the second sensor are eddy current sensors. [5] The grinding wheel truing device described in [4], characterized in that the center of the truer in the Z direction is aligned with the center position of the grinding wheel by moving the truer so that the difference between the first position and the second position becomes a specific value. [6] The grinding wheel truing device according to [5], wherein a first face angle of the end face of the rough grinding truer is smaller than a second face angle of the end face of the fine grinding truer. [7] The grinding wheel truing device described in [2], further comprising a shape measuring unit which measures two-dimensional cross-sectional shapes of the rough grinding truer, the fine grinding truer, and the grinding wheel, a displacement evaluation unit which measures deformation of the rough grinding truer or the fine grinding truer, and the grinding wheel, a vibration measuring unit which measures vibrations of the rough grinding truer or the fine grinding truer, and the grinding wheel, and a processing heat evaluation unit which measures temperature and heat flow, wherein the control unit controls the cutting depth, rotational speed, and position of the rough grinding truer and the fine grinding truer as processing conditions based on evaluations by the displacement evaluation unit, the vibration measuring unit, and the processing heat evaluation unit. [8] A truing device for a grinding wheel as described in [7], characterized in that it comprises a processing condition database that associates the processing conditions with the measurement results by the shape measuring unit after processing, and a processing learning model constructed from the processing condition database. [9] A method for truing a grinding wheel used in a wafer chamfering device, comprising the steps of: truing the grinding wheel using a rough grinding truer to roughly conform to a rough grinding target shape; and, when the grinding wheel is within the tolerance of the rough grinding target shape, truing the grinding wheel using a fine grinding truer having a larger grit size than the rough grinding truer to precisely conform to the fine grinding target shape.

[10] A method for truing a grinding wheel as described in [9], characterized in that a target shape of the grinding wheel is determined, the truing is performed according to a truing program reflecting the two-dimensional cross-sectional shape and displacement conditions of the rough grinding truer or the fine grinding truer and the grinding wheel measured before processing, and during the truing, monitoring is performed using a displacement evaluation unit that measures the deformation of the rough grinding truer or the fine grinding truer and the grinding wheel, a vibration measurement unit that measures the vibration of the rough grinding truer or the fine grinding truer and the grinding wheel, and a processing heat evaluation unit that measures temperature and heat flow, and the processing conditions and the measurement results by a shape measurement unit that measures the two-dimensional cross-sectional shape of the rough grinding truer or the fine grinding truer and the grinding wheel after processing are associated with each other to form a processing condition database, and a processing learning model is constructed from the processing condition database. Effect of the Invention

[0013] According to the present invention, the rough grinding truer performs high-speed trueing as rough machining, leaving the machining portion, and when the grinding wheel is within the tolerance range of the rough grinding target shape, trueing is performed as precision machining using the precision grinding truer, which has a larger grinding wheel grit than the rough grinding truer. This not only allows the shape of the grinding wheel having a complex groove shape to be formed with high precision and quality, but also shortens the time required for truing even for difficult-to-machine materials. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a partial cross-sectional view showing a truer according to an embodiment of the present invention. [Diagram 2] Diagram showing the wafer chamfering process [Diagram 3] An explanatory diagram of factors related to processing accuracy when truing [Figure 4] FIG. 1 is an explanatory diagram of alignment of a truer and a grinding wheel according to an embodiment; [Diagram 5] 1 is a configuration diagram of an alignment unit according to an embodiment; [Figure 6] FIG. 1 is a block diagram showing an overall system configuration of a truing device according to an embodiment; [Figure 7] 1 is a flow chart of a truing method according to one embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] FIG. 1 is a partial cross-sectional view showing a truer 10 according to an embodiment of the present invention, and FIG. 2 is a diagram showing a procedure for chamfering the edge of a wafer by a chamfering device. The chamfering is performed by the truer 10 transferring or processing (truing) the grinding wheel 16, and then grinding the shape of the wafer W by the grinding wheel 16. In FIG. 2, the grinding wheel 16 is attached to a grinding wheel spindle 17 via a quill 18 and rotates. Since this is helical grinding, the truer 10 transfers the shape of the edge of the wafer W as an upper surface angle θ1 and a lower surface angle θ2, and the wafer W transfers the shape of the edge of the wafer W as an upper surface angle θ1' and a lower surface angle θ2'. For example, the upper surface angle θ1 of the truer 10 corresponds to the angle of the upper slope of the end of the truer 10, and the lower surface angle θ2 of the truer 10 corresponds to the angle of the lower slope of the end of the truer 10. For example, the upper surface angle θ1' of the wafer W corresponds to the angle of the upper slope of the end portion of the wafer W, and the lower surface angle θ2' of the wafer W corresponds to the angle of the lower slope of the end portion of the wafer W. The upper surface angle and / or the lower surface angle may be simply referred to as the surface angle.

[0016] The truer 10 has a rough grinding truer 10-1 for rough processing and a fine grinding truer 10-2 for finish processing. The truer 10 may be configured so that the rough grinding truer 10-1 and the fine grinding truer 10-2 are interchangeable. As shown in FIG. 1(a), the cross-sectional shape of the rough grinding truer 10-1 and the cross-sectional shape of the fine grinding truer 10-2 are substantially the same. Note that the cross-sectional shape of the rough grinding truer 10-1 and the cross-sectional shape of the fine grinding truer 10-2 may be the same or different. The rough grinding truer 10-1 can be disposed coaxially with the fine grinding truer 10-2. The axes of the fine grinding truer 10-1 and the fine grinding truer 10-2 may be slightly misaligned. For example, as shown in Fig. 1(a), the truer 10 is formed integrally in two stages, a rough grinding truer 10-1 and a fine grinding truer 10-2. The rough grinding truer 10-1 and the fine grinding truer 10-2 may be directly bonded together, or may be connected via a member containing metal, resin, or the like. In the example shown in Fig. 1(a), a fine grinding truer 10-2 is provided (or bonded) on top of a rough grinding truer 10-1. Note that a fine grinding truer 10-2 may be provided (or bonded) below the rough grinding truer 10-1. Truing by the rough grinding truer 10-1 removes the rough grinding target shape at high speed as rough processing, leaving a machining portion of 10 to 20% of the final target shape (fine grinding target shape) of the grinding wheel 16. In other words, the rough grinding target shape is set to a size of 80 to 90% of the fine grinding target shape, and truing by the rough grinding truer 10-1 is performed faster than truing by the fine grinding truer 10-2, leaving a machining portion by the fine grinding truer 10-2, improving grinding efficiency.

[0017] After truing by the rough grinding truer 10-1, truing is performed by the precision grinding truer 10-2. The precision grinding truer 10-2 performs truing with high accuracy on the part remaining after the rough processing as a precision processing. Therefore, the face angle of the rough grinding truer 10-1 is set to be 1 to 3 degrees smaller than the face angle θ that is the design value of the wafer W, as shown in FIG. 1(b).

[0018] Also, it is preferable that the face angle of the rough grinding truer 10-1 is smaller than that of the precision grinding truer 10-2. However, the shapes of the rough grinding truer 10-1 and the precision grinding truer 10-2 may be exactly the same and adjusted by processing conditions. The grindstone size (grit size) of the precision grinding truer 10-2 is larger than that of the rough grinding truer 10-1, and the size of the abrasive grains is smaller. In other words, the precision grinding truer 10-2 has a finer grit than the rough grinding truer 10-1.

[0019] As shown in Fig. 1, truing using the rough grinding truer 10-1 and the fine grinding truer 10-2 can reduce the time required for truing by using a processing program that utilizes a processing condition database that accumulates rough processing and processing history that greatly approaches the target shape. The rough grinding truer 10-1 and the fine grinding truer 10-2 may be integrated in two stages as shown in Fig. 1, or may be separated and made separately replaceable. Even when separated and replaced according to the purpose, by applying the alignment of this embodiment described later, it is possible to replace the rough grinding truer 10-1 and the fine grinding truer 10-2 more quickly than by alignment by eye alignment or the like.

[0020] Fig. 3 is an explanatory diagram of factors related to processing accuracy during truing, and it is desirable to automate truing and control the accuracy to improve quality. On the other hand, current truing is performed by aligning the position by eye alignment, and creating processing conditions by the craftsman's intuition. Truing work for helical grinding in particular takes time, and it can take more than half a day to set the various conditions.

[0021] Factors related to the processing accuracy are bending, twisting, vibration, and runout of the grinding wheel 16, the surface shape of the truer 10, the state of the abrasive grains, and the force applied during shape transfer f 1 and deformation of the truer 10, processing heat and coefficient of thermal expansion (CTE), alignment of the truer 10 and grinding wheel 16, etc. Therefore, in order to improve the processing accuracy, it is necessary to build a processing control model that analyzes the effect of deformation due to force, heat, etc. on processing accuracy, identify factors that strongly affect performance, and use machine learning to automate the process. In particular, it is important to sense the positions of the truer 10 and grinding wheel 16 in the grinding environment and align them based on the measurements.

[0022] 4 is an explanatory diagram of the alignment of the truer 10 and the grinding wheel 16. The laser displacement meter 20 measures the two-dimensional cross-sectional shapes of the truer 10 and the grinding wheel 16. The position where the center T of the end face of the truer 10 and the center position M of the groove bottom of the grinding wheel 16 coincide based on the measurement by the laser displacement meter 20 is set as the reference position, and the center T of the end face of the truer 10 is moved to the center position M of the groove bottom of the grinding wheel 16 to perform alignment.

[0023] The alignment is performed by embedding a first conductor (or magnetic body) 23-1 in the grinding wheel 16 and a second conductor (or magnetic body) 23-2 in a chuck table 24 that fixes the truer 10, and detecting the positions with eddy current sensors 21-1 and 21-2. The eddy current sensor 21 also measures the displacement of the grinding wheel due to the processing force during processing, and the relationship between the grinding force and deformation of the truer 10 and the grinding wheel 16 is obtained in advance.

[0024] 5 is a configuration diagram of the alignment unit, in which the truer 10 is fixed to a chuck table 24. The second conductor (or magnetic body) 23-2 is embedded in the chuck table 24. The first conductor (or magnetic body) 23-1 is embedded in the center of the groove bottom of the grinding wheel 16. The moving stage 22 has a length measurement function, and has eddy current sensors 21-1 and 21-2 attached to it.

[0025] Eddy current sensor 21-1 is attached to a position facing first conductor (or magnetic body) 23-1 so as to be movable in the Z direction, and determines the position of the center of the groove bottom of grinding wheel 16 as Z1. Eddy current sensor 21-2 is attached to a position facing second conductor 23-2 (or magnetic body) so as to be movable in the Z direction, and determines the position of center T of the end face of truer 10 as Z2. The alignment of center T of the end face of truer 10 and center position M of the groove bottom of grinding wheel 16 is achieved by moving truer 10 so that the difference between Z1 and Z2 is a specified value, and the positions coincide with the set reference position. In the embodiment, the sensors that detect the positions of the truer 10 (or the chuck table 14) and the grinding wheel 16, respectively, are eddy current sensor 21-1 and eddy current sensor 21-2, but sensors other than eddy current sensors 21-1 and 21-2 may be used as long as they are capable of detecting the positions of the truer 10 (or the chuck table 14) and the grinding wheel 16, respectively.

[0026] 6 is a block diagram showing the overall system configuration of the truing device for the grinding wheel 16. The control unit 30 controls (or adjusts) the cutting depth, rotation speed, position, etc. of the truer 10 as processing conditions based on evaluations by a displacement evaluation unit 31, a vibration measurement unit 32, and a processing heat evaluation unit 33. The displacement evaluation unit 31 evaluates the deformation (displacement) caused by the truer 10 and the grinding wheel 16 during processing based on measurements made by a force-displacement measurement unit 36.

[0027] For example, the displacement evaluation unit 31 applies a known force to the truer 10, measures and models the displacement of the truer 10 at that time, and measures and rates (quantifies based on a standard) the deformation (displacement from no load) of the truer 10 and grinding wheel 16 during processing. The vibration measurement unit 32 measures the vibration of the truer 10 and grinding wheel 16 during processing.

[0028] The vibration measuring unit 32 may be common to the laser displacement meter 20 and the eddy current sensor 21 shown in Fig. 4. The processing heat evaluating unit 33 evaluates the processing heat of the truer 10 and the grinding wheel 16 using the measured values ​​of temperature and heat flow by the thermocouple and the heat flow meter constituting the temperature and heat flow measuring unit 34.

[0029] The shape measuring unit 35 is composed of a laser displacement meter 20 and the like, and measures at least the two-dimensional cross-sectional shapes of the truer 10 and the grinding wheel 16. The grinding wheel 16 is attached to a grinding wheel spindle 17. The truer 10 is fixed to a chuck table 24 mounted on a truer moving table 25, and is rotatable around a rotation axis and movable in a plurality of directions along the X, Y, and Z axes. The machining condition database 37-1 monitors the machining conditions and stores them in association with the measurement results of the shape measuring unit 35 after machining. The stored results are constructed as a machining learning model 37-2. The control unit 30 also controls the grinding heat generated by the cooling water system.

[0030] 7 is a flowchart of the truing method. First, a target shape of the grinding wheel 16 is determined, and the target shape is converted into data (step S1). In step S1, the two-dimensional cross-sectional shapes of the truer 10 and the grinding wheel 16 measured before processing in step S35 and the displacement conditions (relationship between grinding force and deformation) of the truer 10 and the grinding wheel 16 modeled in step S31 are reflected in a truing program (step S2). (Step S2)

[0031] The following series of processes are performed according to the truing program. In the rough processing, the grinding wheel 16 is trued by the rough grinding truer 10-1 so as to have a rough grinding target shape that leaves a machining allowance for the later precision processing (step S3). Step S3 is performed by setting the position where the center T of the end face of the rough grinding truer 10-1 coincides with the center position M of the groove bottom of the grinding wheel 16 as measured by the laser displacement meter 20 as the reference position, as shown in FIG.

[0032] After rough machining, the shapes of the truer 10 and grinding wheel 16 are measured by the laser displacement meter 20 of the shape measuring unit 35, and compared with the target shape for rough grinding to determine whether to proceed to the next step of precision machining. If the trued grinding wheel 16 is not within the tolerance range of the target shape for rough grinding, the process returns to the rough machining step of step 3. Measuring the shape of the truer 10 also correlates the machining conditions with the two-dimensional cross-sectional shape after machining, stores the results in a database as a machining condition database 37-1, and constructs a machining learning model 37-2, which contributes to higher precision.

[0033] When the grinding wheel 16 falls within the tolerance range of the target shape for rough grinding, the precision grinding truer 10-2 trues the grinding wheel 16 to the target shape for fine grinding (step S4). Step S4 is performed by setting the position where the center T of the end face of the precision grinding truer 10-2 and the center position M of the groove bottom of the grinding wheel 16 coincide with each other as the reference position, as measured by the laser displacement meter 20. After precision machining, the shapes of the precision grinding truer 10-2 and the grinding wheel 16 are measured by the laser displacement meter 20 of the shape measuring unit 35 (step S5), and a pass / fail judgment is made (step S6).

[0034] If the trued precision grinding truer 10-2 is not within the tolerance of the precision grinding target shape, the process returns to the precision machining process of step 4. If it is within the tolerance of the precision grinding target shape, the wafer W is ground with the grinding wheel 16 to which the shape has been transferred, and the quality of the edge against the design value (target value) is judged.

[0035] The quality judgment of the truer 10 in steps S3 and S4 may utilize results stored in advance in the processing condition database 37-1. Also, the quality judgment of the grinding wheel 16 after rough machining in step 3 is preferably performed using the results stored in the processing condition database 37-1.

[0036] During truing in the series of processes from step 3 to step 6, monitoring is performed by the displacement evaluation unit 31, the vibration measurement unit 32, the processing heat evaluation unit 33, etc., and the processing conditions and the results of the post-processing shape measurement unit 35 are associated with each other and a database is created (step S37). A machining learning model 37-2 for high-precision, high-speed machining is constructed from a database of machining conditions 37-1. The truing program refers to the machining learning model 37-2.

[0037] The processing learning model 37-2 is a machine learning model that outputs the results of evaluation and judgment by a computer for input data. For example, the processing learning model 37-2 can output optimal processing conditions by inputting values ​​monitored by the displacement evaluation unit 31, the vibration measurement unit 32, the processing heat evaluation unit 33, etc. The truing program inputs queries to the processing learning model 37-2 as necessary and obtains the results of evaluation and judgment.

[0038] As described above, in the above embodiment, in the manufacturing process of semiconductor wafers, truing of the grinding wheel 16 involved in chamfering is performed in two stages by the rough grinding truer 10-1 and the fine grinding truer 10-2, so that even in helical grinding of difficult-to-machine materials, the machining speed can be improved and high precision of the groove shape can be achieved. Furthermore, truing time can be reduced by rough machining that greatly approaches the target shape and a truing program that implements an efficient tool path using the machining condition database 37 and machining learning model 37-2.

[0039] The explanation of Figures 2 and 3 has been given of the transfer of the shape of the truer 10, but in order to achieve even higher precision, it is better to machine the upper or lower part of the groove to be formed in the grinding wheel 16 with the precision grinding truer 10-2, and then grind one side at a time by lowering or raising the truer 10 in the thickness direction relative to the grinding wheel 16.

[0040] In addition, in order to bring the truing of the grinding wheel 16 closer to the target shape, most of the wafer is removed by the rough grinding truer 10-1, and then the precision grinding truer 10-2 is used to perform the truing with high precision. This is applicable to wafers W made of 4H-SiC, which is a difficult-to-process material, other polytypes (3C-SiC, 6H-SiC, 15R-SiC, etc.), and materials with large band gaps that are difficult to process, such as GaN (gallium nitride), gallium oxide, and AlGaN. Even with difficult-to-process materials, the processing time by the grinding wheel 16 can be shortened, and high quality can be achieved, particularly with a highly accurate shape formation and a uniform surface condition (waviness and roughness) that is suitable for subsequent processes. [Explanation of symbols]

[0041] 10. Trua 10-1…Sorry, Trua 10-2…Seiken Tsurua 16...Grinding wheel 17…Grinding wheel spindle 18. Quill 20...Laser displacement gauge 21... Eddy current sensor 22...Mobile stage 23-1…First conductor 23-2…Second conductor 24…Chuck table 25…Tsurua mobile stand 30...Control section 31...Displacement evaluation section 32…Vibration measurement section 33…Heat Processing Evaluation Section 34...Temperature / heat flow measurement section 35...Shape measurement section 36…Displacement measurement section 37-1... Processing condition database 37-2…Processed learning model M…Groove bottom center position T…Central part of end face W: Wafer

Claims

1. In a truing device for grinding wheels used in a wafer chamfering device, a truer formed integrally in two stages, including a rough grinding truer and a fine grinding truer that is arranged coaxially with the rotation axis of the rough grinding truer and has a finer mesh than the rough grinding truer; a first sensor that detects a first position corresponding to at least one of the rough grinding truer and the fine grinding truer in a Z direction along the rotation axis; a second sensor for detecting a second position of the grinding wheel in the Z direction; a control unit that adjusts the Z-direction positions of the truer and the grinding wheel based on the first position and the second position, measures the shapes of the truer and the grinding wheel after rough machining by the rough grinding truer, and determines whether to move on to precision machining by the fine grinding truer.

2. 2. The grinding wheel truing device according to claim 1, wherein the rough grinding truer and the fine grinding truer are connected in the Z direction.

3. a chuck table for fixing the truer; 3. The grinding wheel truing device according to claim 2, wherein the first sensor detects the first position of the chuck table.

4. the chuck table has a first conductive material or a first magnetic material, the grinding wheel has a second conductive material or a second magnetic material, 4. The grinding wheel truing device according to claim 3, wherein the first sensor and the second sensor are eddy current sensors.

5. The grinding wheel truing device according to claim 4, characterized in that the center of the truer in the Z direction and the center position of the grinding wheel are aligned by moving the truer so that the difference between the first position and the second position becomes a specific value.

6. 6. The grinding wheel truing device according to claim 5, wherein a first face angle of the end face of said rough grinding truer is smaller than a second face angle of the end face of said fine grinding truer.

7. a shape measuring unit for measuring two-dimensional cross-sectional shapes of the rough grinding truer, the fine grinding truer, and the grinding wheel; a displacement evaluation unit for measuring deformation of the rough grinding truer or the fine grinding truer and the grinding wheel; a vibration measuring unit for measuring vibrations of the rough grinding truer or the fine grinding truer and the grinding wheel; a processing heat evaluation unit that measures temperature and heat flow, 3. The grinding wheel truing device according to claim 2, wherein the control unit controls the cutting depth, rotation speed, and position of the rough grinding truer and the fine grinding truer as processing conditions based on the evaluations of the displacement evaluation unit, the vibration measurement unit, and the processing heat evaluation unit.

8. a processing condition database in which the processing conditions are associated with measurement results obtained by the shape measuring unit after processing; 8. The grinding wheel truing device according to claim 7, further comprising: a machining learning model constructed from the machining condition database.

9. A method for truing a grinding wheel used in a wafer chamfering device, comprising a rough grinding truer and a fine grinding truer arranged coaxially with the rotation axis of the rough grinding truer and having a finer mesh than the rough grinding truer, the truer being integrally formed in two stages, a first sensor for detecting a first position corresponding to at least one of the rough grinding truer and the fine grinding truer in the Z direction along the rotation axis, and a second sensor for detecting a second position of a grinding wheel used in the wafer chamfering device in the Z direction, Based on the first position and the second position, the positions of the truer and the grinding wheel in the Z direction are adjusted, and the grinding wheel is trued as rough processing by the rough grinding truer so that it becomes a rough grinding target shape; measuring the shapes of the truer and the grinding wheel and comparing them with the rough grinding target shape to determine whether to proceed to the next fine grinding process; A method for truing a grinding wheel, characterized in that when it is determined that the grinding wheel has fallen within the tolerance range of the rough grinding target shape, the Z-direction positions of the truer and the grinding wheel are adjusted based on the first position and the second position, and the truing is performed as precision processing using the fine grinding truer so that the grinding wheel reaches the fine grinding target shape.

10. A target shape of the grinding wheel is determined, and the truing is performed according to a truing program that reflects the two-dimensional cross-sectional shapes and displacement conditions of the rough grinding truer or the fine grinding truer and the grinding wheel measured before processing; During the truing, monitoring is performed by a displacement evaluation unit that measures deformation of the rough grinding truer or the fine grinding truer and the grinding wheel, a vibration measurement unit that measures vibration of the rough grinding truer or the fine grinding truer and the grinding wheel, and a processing heat evaluation unit that measures temperature and heat flow, The processing conditions are associated with the measurement results of a shape measuring unit that measures the two-dimensional cross-sectional shapes of the rough grinding truer or the fine grinding truer and the grinding wheel after processing, and the results are stored as a processing condition database. The grinding wheel truing method according to claim 9, wherein a machining learning model is constructed from the machining condition database.

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