Chamfering device for wafer

Abstract

To provide a chamfering device for a wafer that can improve allowable accuracy of a wafer and shipping quality such as variation and lengthen a service life of a truer preparation grinding stone maximally.SOLUTION: A chamfering device for a wafer, which is configured to subject a grinding stone 16 to truing using a truer 10 (S4) and to grind an edge part at an outer periphery of a wafer W using the grinding stone 16 subjected to truing (S4), comprises: truer preparation grinding stones 15 that prepare an edge shape of the truer 10 in accordance with a truer processing program 50; a control part 30 that controls processing conditions of the truer preparation grinding stones 15, the truer 10 and the grinding stone 16; and a truer preparation grinding stone evaluating part 39 that evaluates the truer preparation grinding stones 15 from a measured result of the edge shape of the truer 10, which creates and renews the truer processing program 50 on the basis of the evaluated result.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer chamfering device that uses a truer to transfer (truing) a peripheral precision grinding wheel (grinding wheel) having a groove shape used in a chamfering device for the end face of a semiconductor wafer, and then uses the transferred peripheral precision grinding wheel to grind the peripheral edge portion of the wafer (semiconductor material substrate). [Background technology]

[0002] In recent years, there has been an increasing demand for higher precision and quality improvements in grinding wheels with groove shapes used in wafer chamfering, with the aim of achieving high-mix, low-volume production, improving wafer quality, and increasing yield.

[0003] In addition, semiconductors using SiC (silicon carbide), a compound of carbon (C) and silicon (Si), as well as other materials with a large band gap (UWBG) and strong bonds between the atoms that make up the crystal, such as GaN (gallium nitride), gallium oxide, AlGaN, and diamond, are expected to be smaller than silicon semiconductors, have lower power consumption, are highly efficient, and offer excellent radiation resistance, and are being put to practical use. However, because UWBG materials such as 4H-SiC are difficult to process, there is a strong demand for higher precision and quality in the groove shape of grinding wheels.

[0004] Chamfering in the manufacturing process of semiconductor wafers requires truing the grinding wheel with a truer and measuring the edge shape of the wafer after grinding, and this process must be repeated until the wafer achieves the desired shape.

[0005] Furthermore, in the finishing process of the outer peripheral chamfer of semiconductor wafers, it is known to perform so-called helical grinding, in which the grinding wheel is tilted relative to the wafer to grind the chamfer, in order to prevent the generation of grinding marks in the circumferential direction.However, helical grinding requires delicate adjustments for the formation of the shape by truing the grinding wheel, which is time-consuming and requires a skilled, dedicated person.

[0006] Patent Document 1 describes that in truing for helical grinding, which uses a truer to form grooves, the upper or lower part of the groove formed in the grinding wheel is processed with a truer in order to improve the transfer rate and processability as well as the accuracy of the grooves formed in the wafer grinding wheel by the truer.

[0007] Furthermore, Patent Document 2 describes forming the edge of the truer into a groove shape that is asymmetrical in the vertical direction, and forming the groove shape by grinding with the truer and a wafer grinding wheel tilted relative to each other. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-167331 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-165712 Summary of the Invention [Problem to be solved by the invention]

[0009] In the above-mentioned prior art, the one described in Patent Document 1 requires adjustments by a skilled, dedicated person to move the truer when truing the grinding wheel used for chamfering.

[0010] Furthermore, the method described in Patent Document 2 has a poor transcription rate due to the load on the truer in the vertical direction and deformation of the truer in the rotational direction, which affects the precision of the grooves formed, the truing time, etc., resulting in a significant decrease in truing efficiency and is insufficient for improving the precision of the overall shape of a grinding wheel having a groove shape.

[0011] Furthermore, the above-mentioned conventional technology requires a truer-prepared grinding wheel that creates the edge of the truer using a truer processing program. However, if the truer-prepared grinding wheel continues to process a specific part of the grinding wheel groove using the same truer processing program, the grinding wheel groove will become deformed due to wear and will no longer be able to withstand the design value, which means that the grinding wheel will reach the end of its life sooner.

[0012] The object of the present invention is to solve the problems of the prior art described above, and to provide a wafer chamfering device which can improve the precision and quality of the shape of the groove-shaped grinding wheel used in the wafer chamfering device by improving the precision of truing, and ultimately improve the shipping quality of the wafer, such as the allowable precision and variation, even for difficult-to-process materials, and can extend and maximize the life of the grinding wheel made by the truing device. [Means for solving the problem]

[0013] In order to achieve the above-mentioned object, the present invention provides a wafer chamfering device that uses a truer to true a grinding wheel and grinds the outer peripheral edge of a wafer using the trued grinding wheel, the device comprising: a truer-making grinding wheel that creates the edge shape of the truer in accordance with a truer processing program; a control unit that controls the truer-making grinding wheel and the processing conditions for the truer and the grinding wheel; and a truer-making grinding wheel evaluation unit that measures the edge shape of the truer and evaluates the truer-making grinding wheel, and creates and updates the truer processing program based on the evaluation.

[0014] Furthermore, in the above-mentioned wafer chamfering device, it is preferable to include a shape measuring unit that measures the cross-sectional shape of the wafer, a processing condition database in which the shape of the wafer processed by the grinding wheel is measured by the shape measuring unit, compared with a target shape, and stored in association with processing conditions, and a learning model constructed from the processing condition database, and the Truer-prepared grinding wheel evaluation unit evaluates the Truer-prepared grinding wheel based on the learning model.

[0015] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer manufacturing grindstone evaluation unit updates the truer processing program when it evaluates that the truer manufacturing grindstone is deformed due to wear.

[0016] Furthermore, in the above-mentioned wafer chamfering device, it is preferable that the truer processing program is created by combining both down-cutting and up-cutting tool paths for the truer manufacturing grindstone.

[0017] Furthermore, in the above-mentioned wafer chamfering device, the edge shape of the truer is formed by moving the work fixing part of the truer in the X-axis, Y-axis, and Z-axis directions and rotating the truer along the rotation axis (θ w ) and rotation about the pitch axis to perform grinding.

[0018] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer processing program is updated by changing the processing procedure of the truer.

[0019] Furthermore, in the above-described wafer chamfering device, it is preferable that the Truer manufactured grindstone evaluation unit monitors the processing load, predicts and identifies unevenly worn portions of the Truer manufactured grindstone, and reflects the results in the Truer processing program.

[0020] Furthermore, in the above-mentioned wafer chamfering device, it is preferable that a motion program for uniformizing the processing use portion of the truer manufacturing grindstone is incorporated into the truer processing program. [Effects of the Invention]

[0021] According to the present invention, a truer processing program is created and updated to evaluate the truer manufacturing grinding wheel from the results of measuring the truer edge shape and to create the truer edge shape, thereby making it possible to obtain a wafer chamfering device that extends the life of the truer manufacturing grinding wheel and improves the precision and quality of the grinding wheel shape. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a control flowchart of a wafer chamfering apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram showing the overall system configuration of a chamfering device according to an embodiment. [Figure 3] An explanatory diagram showing the processing procedure for grinding the chamfered portion of the wafer edge [Figure 4] Cross-sectional view of Truer and Truer-made grinding wheels [Figure 5] A side view showing the configuration of the machine shaft used to create the edge shape of the truer [Figure 6] An explanatory diagram showing the edge shape creation of the truer (Example 1 of the creation of the upper and lower side widths) [Figure 7] An explanatory diagram showing the creation of the edge shape of the truer (Example 2 of the creation of the upper and lower side widths) [Figure 8] An explanatory diagram showing the creation of the edge shape of the truer (Example 1 of the creation of the flat width) [Figure 9] An explanatory diagram showing the creation of the edge shape of the truer (Example 2 of the creation of the flat width) [Figure 10] An explanatory diagram showing the edge shape creation of the truer (Example 1 of creation of upper tip radius R1 and lower tip radius R2) [Figure 11] An explanatory diagram showing the edge shape creation of the truer (Example 2: creation of upper tip radius R1 and lower tip radius R2) [Figure 12] A cross-sectional side view showing the processing state in creating the edge shape of the truer [Figure 13] An explanatory diagram showing the processing procedure of the truer 10 according to the truer processing program 50 (Example 1) [Figure 14] An explanatory diagram (Example 2) showing the processing procedure of the truer 10 by the truer processing program 50 [Figure 15] An explanatory diagram showing the state of grinding using the tip surface of the convex part of the grinding wheel 15 made by Trua DETAILED DESCRIPTION OF THE INVENTION

[0023] FIG. 1 is a control flowchart of a chamfering device for a wafer W according to one embodiment of the present invention, FIG. 2 is a block diagram showing the overall system configuration of the chamfering device according to one embodiment, and FIG. 3 is an explanatory diagram showing the processing procedure for grinding the chamfered portion of the wafer edge surface.

[0024] 3, the chamfering is performed by grinding the edge shape of the truer 10 with a truer making grindstone 15. The groove shape of the grinding wheel 16 is transferred (trued) by the truer 10, and then the outer peripheral shape of the wafer W is ground with the grinding wheel 16.

[0025] In Figure 3, the grinding wheel 16 is attached to a grinding wheel spindle 17 via a quill 18 and rotates. Because this is helical grinding, the truer 10 is ground with an upper surface angle θ1 and a lower surface angle θ2 on the end face, and the wafer W is ground with an upper surface angle θ1' and a lower surface angle θ2'.

[0026] Factors affecting the machining accuracy during truing include bending, twisting, and vibration of the grinding wheel 16, the surface shape of the truer 10, the state of the abrasive grains, the force applied during shape transfer, deformation of the truer 10, processing heat and thermal expansion coefficient, and alignment of the truer 10 and grinding wheel 16. To improve machining accuracy, it is necessary to create a machining condition database 37 that analyzes the effect of deformation due to force, heat, etc. on machining accuracy, identify factors that have a strong influence on performance, and build a learning model 38 using machine learning for automation.

[0027] In particular, it is important to sense the positions of the truer 10 and the grinding wheel 16 in the grinding environment and align them based on measurements. Although not shown, the amount of cut into the grinding wheel 16 is required as a condition for truing, so the wheel groove diameter D of the grinding wheel 16 is calculated sequentially.

[0028] Taking into account factors related to processing accuracy, the truer 10 is required to have an upper surface angle θ1 of the truer 10 < an upper surface angle θ1' of the wafer W, and a lower surface angle θ2 of the truer 10 < a lower surface angle θ2' of the wafer W. The allowable shape accuracy of the truer 10 is determined by the allowable shape accuracy of the wafer W (shipping quality).

[0029] The edge shape of the truer 10 is created by grinding the edge of the truer 10 by moving it relatively to the truer making grinding wheel 15 (using a machine axis attached to the table that fixes the workpiece) and creating a desired arbitrary shape. The environment in which the truer making grinding wheel 15 is installed is an environment where coolant, fallen abrasive grains, chips, etc. are present, making it difficult to directly measure the shape of the grinding wheel grooves of the truer making grinding wheel 15. It is preferable to determine that the truer making grinding wheel 15 has reached the end of its life when it deviates from the allowable shape accuracy of the wafer W or the allowable shape accuracy of the truer 10.

[0030] The chamfering device according to one embodiment determines the change in shape of the grinding groove of the truer-made grinding wheel 15 from the edge shape of the truer 10 that serves as the workpiece. The truer-made grinding wheel evaluation unit 39 evaluates the change in shape due to wear of the truer-made grinding wheel 15, surface roughness, etc., predicts (simulates) the grinding wheel groove life, etc., and creates and updates the truer processing program 50 so as to maximize the life of the truer-made grinding wheel 15.

[0031] In other words, the chamfering device in one embodiment evaluates and predicts deformation of the truer manufacturing grinding wheel 15 due to wear, etc., using shape evaluation, etc., comparing the edge shape of the truer 10 manufactured by the truer manufacturing grinding wheel 15 and the edge shape of the wafer W processed by the grinding wheel 16 transferred using the truer 10 with the target shape.

[0032] Then, a truer processing program 50 is created to improve the life of the truer manufacturing grinding wheel 15 (step S1 in FIG. 1). The truer processing program 50 is created by constructing a learning model 38 by machine learning that describes the relationship between the edge shape of the truer 10, the grinding wheel 16, the edge shape of the wafer W, the life of the truer manufacturing grinding wheel 15, and the truer processing program 50.

[0033] Updating and creating the Truer processing program 50 to maximize the life of the Truer-made grinding wheel 15 reduces the frequency of replacement of the Truer-made grinding wheel 15, preventing the production line (operation) from being affected by the man-hours required for replacement and adjustment. This is particularly effective when the Truer-made grinding wheel 15 is installed next to a rough peripheral grinding wheel, where the number of grooves on the Truer-made grinding wheel 15 is limited due to space constraints.

[0034] However, depending on the operating conditions, it may be preferable to operate the truer 10 without measuring the edge shape. In that case, evaluation of the change in the shape of the grinding wheel groove of the truer-made grinding wheel 15 and prediction of the lifespan may be performed by finding a correlation when creating the processing condition database 37 or as a result of learning.

[0035] 2, the control unit 30 controls the cutting depth, rotation speed, position, movement amount, processing load, etc. of the truer making grindstone 15, the truer 10, and the grinding stone 16 as processing conditions. The shape measurement unit 35 is composed of a laser displacement meter, etc., and measures the two-dimensional cross-sectional shape and surface roughness, etc. of the truer 10, grinding stone 16, and wafer W, which are the workpieces (objects to be processed) of the chamfering device.

[0036] A grinding wheel 16 serving as a tool is attached to the grinding wheel spindle 17. Similarly, the Truer-prepared grinding wheel 15 may also be attached to the grinding wheel spindle 17. The Truer-prepared grinding wheel 15 may also be attached to another spindle. For example, as will be described later, it may be attached to another movable carriage 25-2. In this case, the Truer-prepared grinding wheel 15 may be provided together with (on the same rotation axis as) another grinding wheel (for example, a rough grinding wheel, etc.). The wafer W and the truer 10, which are the workpieces, are placed on a workpiece moving table 25 and fixed to a workpiece fixing unit 24, which is made up of a vacuum chuck table. The workpieces are movable in the X-axis, Y-axis, and Z-axis directions and rotated along a rotation axis (θ w ), which allows rotation around the pitch axis.

[0037] In addition, the system configuration preferably includes a displacement evaluation unit (not shown) that evaluates the deformation (displacement) of the truer 10 and grinding wheel 16 during machining. The displacement evaluation unit measures the deformation (displacement from no load) of the truer 10 and grinding wheel 16 during machining based on the modeled displacement conditions of the truer 10 and grinding wheel 16, and measures the vibration of the truer 10 and grinding wheel 16 during machining, and provides a rating (quantification based on standards).

[0038] The processing condition database 37 stores the results of monitoring the processing conditions of the truer 10 and the grinding wheel 16, such as the depth of cut, rotation speed, position, amount of movement, processing load, displacement, vibration, processing heat, etc., in association with the measurement results of the shape measuring unit 35 after truing.

[0039] The stored results are constructed as a learning model 38. As shown in Figure 1, the learning model 38 is obtained as a machining learning model 38-1, and an analysis-based machining model 38-2 that reflects the shapes of the truer 10 and grinding wheel 16 measured before machining and the displacement conditions of the modeled truer 10 and grinding wheel 16.

[0040] In the control flowchart of Figure 1, the chamfering device optimizes the shape of the truer 10 so that the wafer W has the allowable shape accuracy of the target shape. The shape of the truer 10 is determined by taking into account the axial displacement conditions of the truer 10 that have been determined in advance, and the truer processing program 50 is created and updated with the upper surface angle θ1, lower surface angle θ2, and chamfering angles of the end faces shown in Figure 3 (Step S1).

[0041] The Truer processing program 50 reflects the cross-sectional shapes of the edges of the Truer 10 and grinding wheel 16 measured by the shape measurement unit 35 (see Figure 2) before processing, the processing condition database 37, the processing learning model 38-1, the analysis-based processing model 38-2, and the evaluation results of the Truer manufacturing grinding wheel evaluation unit 39.

[0042] The edge shape of the truer 10 is produced by grinding with the truer production grindstone 15 in accordance with the truer processing program 50 (step S2). The shape measuring unit 35 measures the edge shape of the manufactured truer 10 (step S3).

[0043] The groove shape of the grinding wheel 16 is transferred (trued) by the manufactured truer 10 (Step S4). If a displacement evaluation unit (not shown) is provided, the vibrations of the truer 10 and grinding wheel 16 during truing are monitored, and if a heat flow measurement unit or the like is provided, the temperature is also monitored.

[0044] The wafer W is ground by the grinding wheel 16 to which the shape has been transferred (step S5), and the shape measuring unit 35 determines whether the wafer W is good or bad relative to a target shape, which is a design value (step S6).

[0045] If the wafer W ground by the grinding wheel 16 is not within the allowable range of edge shape accuracy, the process returns to step S1. The processing conditions and the cross-sectional shape after processing are associated and stored in a database as a processing condition database 37, and are reflected in the processing learning model 38, which is a processing learning model 38-1 and an analysis-based processing model 38-2 (step S7).

[0046] The processing condition database 37 stores the results of monitoring the processing conditions during truing (step S4) and during outer periphery grinding of the wafer W (step S5) in association with the truer processing program 50, the edge shape of the truer 10, the workpiece processing operating conditions, and the target workpiece shape. The processing learning model 38-1 is constructed from the processing condition database 37 that has been stored as a database.

[0047] The Truer-manufactured grinding wheel evaluation unit 39 is constructed from a machining learning model 38-1, an analysis-based machining model 38-2, etc., which serve as a learning model 38, and evaluates the Truer-manufactured grinding wheel 15 based on the learning model 38. The Truer-manufactured grinding wheel evaluation unit 39 creates and updates the Truer-manufactured grinding wheel 15 based on an evaluation of a change in shape of the Truer-manufactured grinding wheel 15. For example, if the Truer-manufactured grinding wheel evaluation unit 39 evaluates that the Truer-manufactured grinding wheel 15 has been deformed due to wear or the like, the Truer-manufactured grinding wheel evaluation unit 39 updates the Truer-manufactured grinding program 50.

[0048] The machining learning model 38-1 is a machine learning model that outputs the results of evaluation and judgment by a computer for the data that is the results accumulated in the machining condition database 37. The truer machining program 50 inputs a query to the machining learning model 38-1 as necessary to obtain the results of evaluation and judgment. In one embodiment, the learning model 38 is used to perform truing (step S2) and outer periphery grinding of the wafer W (step S5), thereby improving the accuracy and quality of the groove shape and suppressing shape variation.

[0049] The explanations in Figures 1 and 3 have been given of the shape transfer of the truer 10, but in order to achieve even higher precision, the upper or lower part of the groove to be formed in the grinding wheel 16 may be machined with the truer 10, and then the truer 10 may be ground on one side at a time by lowering or raising it in the thickness direction relative to the grinding wheel 16.

[0050] The method for evaluating the Truer manufactured grindstone 15 by the Truer manufactured grindstone evaluation unit 39 is as follows: (1) A first method (without measuring the edge shape of the truer 10) in which the determination is made based on the measurement results of the wafer W shape after grinding (step S6 in FIG. 1). (2) A second method in which the true edge shape is determined based on the measurement results (step S3 in FIG. 1 ). The method is carried out by either (1) or (2), or by combining the first and second methods.

[0051] FIG. 4 shows a cross-sectional view of the truer 10 and the truer manufacturing grindstone 15. The detailed shape of the truer 10 is machined to have a thickness t, an upper surface width X1, a lower surface width X2, a truer plane width X3, an upper tip radius R1, and a lower tip radius R2. In describing the present invention, the upper surface width X1, the lower surface width X2, the truer plane width X3, the upper tip radius R1, and the lower tip radius R2 may be used to refer to the surface of the truer 10 indicated by the dimension X1 in FIG. 4. The same applies to the lower surface width X2, the truer plane width X3, the upper tip radius R1, the lower tip radius R2, and others. The truer 10 is pressed against a truer making grindstone 15 as shown by the arrow and ground.

[0052] The truer-made grinding wheel 15 mainly has the upper side width X1 of the truer 10 corresponding to the upper slope CX1 of the truer-made grinding wheel 15, the lower side width X2 corresponding to the lower slope CX2, the truer plane width X3 corresponding to the plane CX3, the upper tip radius R1 corresponding to the upper circular arc CR1, and the lower tip radius R2 corresponding to the lower circular arc CR2.

[0053] 5 is a side view showing the configuration of the machine axes in the edge shape creation (step S2 in FIG. 1) of the truer 10. The truer 10, which serves as the workpiece, is fixed to a workpiece fixing part 24, which is movable in the X-axis, Y-axis, and Z-axis directions and rotates around a rotation axis (θ w ) is installed on the workpiece moving stage 25-1, which can rotate around the pitch axis. However, the pitch axis is parallel to the Y axis, and the workpiece fixing part (workpiece) and the rotation axis θw rotate around the pitch axis, but at that time, the movement directions of the X axis and Z axis do not change. The truer-made grindstone 15 is installed on the workpiece moving stage 25-1, which can rotate around the rotation axis (θ t ) axis as the rotation axis. The truer 10 side may have a four-axis configuration in which the pitch axis is omitted. Here, the up-down arrow K shown in FIG. 5 indicates that the tip of the truer 10 rotates up and down as indicated by the arrow as the truer 10 rotates around the pitch axis. The tip of the truer 10 on the side of the truer making grindstone 15 is indicated by an arrow as the truer tip.

[0054] 6 to 11 are explanatory diagrams showing the edge shape production of the truer 10. The grindstones used to grind the truer 10 shown here are the truer production grindstone 15 shown in FIG. 5 and its variation, the second truer production grindstone 19. In other words, it is shown that the truer 10 can be ground not only using the truer production grindstone 15 but also using the second truer production grindstone 19, which has a different shape. FIG. 6 shows Example 1 of production of the upper side width X1 and lower side width X2 of the truer 10, FIG. 7 shows Example 2 of production of the upper side width X1 and lower side width X2 of the truer 10, FIG. 8 shows Example 1 of production of the truer flat width X3, FIG. 9 shows Example 2 of production of the truer flat width X3, FIG. 10 shows Example 1 of production of the upper tip radius R1 and the lower tip radius R2, and FIG. 11 shows Example 2 of production of the upper tip radius R1 and the lower tip radius R2.

[0055] 6 shows a case where the truer 10 is not rotated around the pitch axis (see FIG. 5) of the truer 10, and shows that the upper side width X1 of the truer 10 is ground by the upper inclined surface CX1 of the truer making grindstone 15. At this time, the truer 10 is rotated by θ w The Truer manufactured grinding wheel 15 rotates at θ t Grinding is performed by rotating around the center of rotation, while the contact surfaces of the truer 10 and truer-made grinding wheel 15 move relatively in the direction of the arrow in Figure 6. A similar method is also used when grinding the lower side width X2 with the lower slope CX2. The main grinding condition parameters are the cutting depth, rotation speed, rotation direction, spark-out time (when no cutting is performed at the end of the grinding process, and only feed is applied or a fine cutting is used to escape), and the movement speeds in X, Y, and Z.

[0056] 7 shows the grinding process when the truer 10 is rotated slightly around the pitch axis. As shown in this figure, by rotating the truer 10 slightly around the pitch axis, the upper side width X1 of the truer 10 can be processed not only on the upper inclined surface CX1 of the truer making grindstone 15, but also on any flat surface of the truer making grindstone 15.

[0057] 8 is a diagram showing that a second truer making grindstone 19, which is a grindstone having a circular portion, is used to grind by relatively moving the second truer making grindstone 19 or the truer 10 so that the truer plane width X3 of the truer 10 moves in the direction of the arrow on its cylindrical portion. In the case of the second truer making grindstone 19 having a circular portion, the second truer making grindstone 19 and the truer 10 can be relatively moved in the tangential direction at the contact point between the circular portion and the truer 10 to grind the flat portion of the truer plane width X3. Fig. 9 shows that the same processing as Fig. 8 can be performed on either flat surface of the truer manufacturing grindstone 15. Also, Fig. 9, like Fig. 8, shows that grinding is performed by moving the truer manufacturing grindstone 15 and the truer 10 relatively so that the truer flat surface width X3 of the truer 10 moves in the direction of the arrow.

[0058] 10 is a diagram showing how the upper tip radius R1 portion of the truer 10 is ground using the second truer manufacturing grindstone 19, which has a circular portion. As shown in FIG. 10, by slightly rotating the truer 10 around the pitch axis, the upper tip radius R1 portion of the truer 10 moves in the direction shown by the arrow in the figure, and is ground by the cylindrical portion of the second truer manufacturing grindstone 19. The same method is used when grinding the lower tip radius R2 portion. Moreover, Fig. 11 shows that it is possible to perform the same processing as Fig. 10. Fig. 11 shows that grinding of the upper tip radius R1 portion of the truer 10 with the upper inclined surface CX1 portion of the truer making grinding wheel 15 is performed by slightly rotating the truer 10 in the direction of the arrow around the pitch axis, as in Fig. 10.

[0059] 12 is a side cross-sectional view showing a machining state in the creation of the edge shape of the truer 10. The creation of the edge shape of the truer 10 is performed in accordance with a truer machining program 50. The creation of the edge shape of the truer 10 is performed by moving the truer 10 in the X-axis, Y-axis, and Z-axis directions of the workpiece fixing part 24, which serves as the machine axis, relative to the truer creating grindstone 15, and rotating the truer 10 in the X-axis, Y-axis, and Z-axis directions of the rotation axis (θ w ) and grinding is performed by rotating the workpiece around the pitch axis.

[0060] For example, the truer machining program 50 may be configured to use the rotation axis (θ w ) and the rotation axis (θ t While rotating both axes (down cut, up cut), the X and Z axes are moved a predetermined amount at a predetermined position on the Y axis to create the shape of the truer 10. The main grinding condition parameters are the depth of cut, rotation speed, rotation direction (down / up), spark-out time, movement speeds of the X, Y, and Z axes, and rotation speed of the pitch axis.

[0061] Down cutting is performed by making the rotation direction D0 of the truer 10 and the rotation direction D1 of the truer-made grinding wheel 15 the same, while creating a speed difference at the contact point (grinding area) between the truer 10 and the truer-made grinding wheel 15. Up cutting is performed by making the rotation direction D1 of the truer-made grinding wheel 15 opposite to the rotation direction D0 of the truer 10, as compared to down cutting. The truer machining program 50 creates the tool path TP of the truer-made grinding wheel 15, which is the path along which the truer-made grinding wheel 15 moves on the surface of the truer 10, by combining both down cutting and up cutting.

[0062] The tool path TP is optimized not only to shorten the movement time of the Truer-manufactured grinding wheel 15, but also to maximize the life of the grinding grooves of the Truer-manufactured grinding wheel 15 based on the evaluation by the Truer-manufactured grinding wheel evaluation unit 39. For example, the Truer-manufactured grinding wheel evaluation unit 39 monitors the machining load to predict and identify unevenly worn areas of the Truer-manufactured grinding wheel 15, and reflects the results in the Truer machining program 50 to maintain the designed shape of the Truer-manufactured grinding wheel 15. In other words, a motion program that makes the parts of the Truer-manufactured grinding wheel 15 used for machining uniform, without uneven distribution, is incorporated into the Truer machining program 50.

[0063] 13 and 14 are explanatory diagrams showing the machining procedure of the truer 10 according to the truer machining program 50. As explained in Figs. 6 to 11, the machining procedure of the truer 10 does not always have to be the same procedure, and can be changed as shown in Example 1 of Fig. 13 and Example 2 of Fig. 14. The machining procedure is changed based on the evaluation of the truer-made grindstone evaluation unit 39, and the portions of the truer-made grindstone 15 used for machining can be made uniform without being unevenly distributed.

[0064] Example 1 in FIG. 13 will be described. The truer 10 is ground by feeding the truer plane width X3 (see Figure 4) of the truer 10 with the plane CX3 (see Figure 4) of the truer grinding wheel 15 as shown by the arrow, and the diameter D of the truer 10 is t (Step 1) Create the upper tip radius R1 of the truer 10 (see Figure 4). (Step 2) The upper side width X1 of the truer 10 (see Figure 4) is prepared (Step 3). Adjust and correct the shape of the upper side width X1 and the upper tip radius R1 (Step 4). Diameter D of Trua 10 t Adjust, correct and finish (Step 5) Step 6: Create the radius R2 (see Figure 4) at the bottom of the truer 10. The width X2 of the bottom surface of the truer 10 (see Figure 4) is prepared (Step 7). Adjust and correct the shape of the lower side width X2 and the lower tip radius R2 (Step 8). Thereafter, steps 1 to 8 are repeated several times to create and finish the edge shape of the truer 10.

[0065] Example 2 in FIG. 14 will be described. Insert the upper tip of the Truer 10 as shown by the arrow. (Step 1') Create the upper side width X1 of the truer 10. (Step 2') Create the upper tip radius R1 of the truer 10. (Step 3') Diameter D of Trua 10 t (Step 4') Create the radius R2 at the lower tip of the truer 10. (Step 5') Create the bottom side width X2 of the truer 10. (Step 6') Adjust and correct the shape of the bottom side width X2. (Step 7') Lower tip radius R2, diameter D t Adjust and correct the upper tip radius R1 and upper surface width X1 (Step 8'). Thereafter, steps 1' to 6' are repeated several times to create and finish the edge shape of the truer 10.

[0066] As described above, when manufacturing the edge shape of the truer 10 using the truer processing program 50, if a large number of wafers W are continuously processed using a specific portion of the grinding groove of the truer manufacturing grindstone 15, this specific portion will become deformed due to wear, etc., and it will no longer be possible to maintain the allowable shape accuracy of the truer 10 and the allowable shape accuracy of the wafers W, and the truer manufacturing grindstone 15 will reach the end of its life beyond its usable limit.

[0067] However, the parts other than the worn parts are still usable. Therefore, the truer processing program 50 does not always process the truer 10 using the same procedure, but changes the procedure to prevent uneven wear, thereby making it possible to maximize the life of the truer making grindstone 15. For example, if the procedure shown in Figure 13 is normally followed and it is determined that there is deformation due to wear or the like in the R1 and R2 portions (see Figure 4) of the truer grinding wheel 15, steps (2) and (6) of Figure 13 can be omitted and steps (1) to (8) can be carried out, and instead of steps (2) and (6), CX1 and CX2 can be used to create R1 and R2 as shown in Figure 11. Alternatively, as shown in the enlarged view of part A in FIG. 5 and FIG. 15, the truer 10 can be rotated around the pitch axis as indicated by the arrow, and R1 and R2 at the tip of the truer 10 can be pressed against the part indicated by symbol e of the truer making grindstone 15, and grinding can be performed as shown in FIG. 11 to make R1 and R2. Here, in Fig. 5, the part indicated by e in the enlarged view of part A is the tip surface of the convex part of the truer-making grindstone 15. Fig. 15 is an explanatory diagram showing the state in which part e, which is the tip surface of the convex part of the truer-making grindstone 15, is pressed against the R2 part of the truer 10 for grinding. Note that both Fig. 5 and Fig. 15 are explanatory diagrams, and are shown in shapes that differ from the actual dimensions and proportions for ease of viewing.

[0068] The prediction and identification of uneven wear areas of the Truer manufactured grinding wheel 15 are performed by evaluation in the Truer manufactured grinding wheel evaluation unit 39 based on a learning model 38 constructed from a processing condition database 37 that associates the processing conditions under which the processing load is monitored with the shapes of the Truer 10 and grinding wheel 16 after processing.

[0069] The edge shape of the truer 10 is produced by the truer manufacturing grindstone 15 based on the truer processing program 50, so by creating and updating the truer processing program 50 based on evaluation in the truer manufacturing grindstone evaluation unit 39, it is possible to maximize the life of the truer manufacturing grindstone 15. [Explanation of symbols]

[0070] 10...Tsurua 15...Tsurua manufactured whetstone 16...Grinding wheel 17...Grinding wheel spindle 18...Quill 19...2nd Trua production whetstone 24...Workpiece fixing part 25...Work moving table 25-1...Work moving table 25-2...Mobile stand 30...Control unit 35...Shape measurement section 37...Processing condition database 38...Learning Model 38-1...Processed learning model 38-2...Analysis-based machining model 39...Tsurua manufactured grinding wheel evaluation section 50...Trua processing program W...wafer

Claims

1. 1. A wafer chamfering apparatus that uses a truer to true a grinding wheel and grinds an outer peripheral edge portion of a wafer using the trued grinding wheel, a truer making grindstone that makes the edge shape of the truer in accordance with a truer processing program; a control unit for controlling the processing conditions of the truer manufacturing grindstone, the truer, and the grinding stone; a truer-manufactured grindstone evaluation unit for measuring the edge shape of the truer and evaluating the truer-manufactured grindstone; and creating and updating the truer processing program based on the evaluation.

2. a shape measuring unit that measures a cross-sectional shape of the wafer; a processing condition database in which the shape of the wafer processed by the grinding wheel is measured by the shape measuring unit, compared with a target shape, and stored in association with processing conditions; a learning model constructed from the processing condition database; 2. The wafer chamfering device according to claim 1, wherein the Truer manufactured grindstone evaluation unit evaluates the Truer manufactured grindstone based on the learning model.

3. 3. The wafer chamfering device according to claim 1, wherein the truer manufacturing grindstone evaluation unit updates the truer processing program when it evaluates that the truer manufacturing grindstone is deformed due to wear.

4. 3. The wafer chamfering device according to claim 1, wherein the truer processing program is created by combining both down-cutting and up-cutting tool paths for the truer manufacturing grindstone.

5. The edge shape of the truer is created by moving the workpiece fixing part of the truer in the X-axis, Y-axis, and Z-axis directions and by rotating the truer along the rotation axis (θ ｗ 3. The wafer chamfering device according to claim 1, wherein grinding is performed by rotating the wafer about the pitch axis.

6. 3. The wafer chamfering apparatus according to claim 1, wherein the truer processing program is updated by changing the processing procedure of the truer.

7. 4. The wafer chamfering device according to claim 3, wherein the truer-prepared grindstone evaluation unit monitors the processing load to predict and identify uneven wear areas of the truer-prepared grindstone and reflects the results in the truer processing program.

8. 4. The wafer chamfering device according to claim 3, wherein a motion program for uniformizing the processing use portion of said truer manufacturing grindstone is incorporated into said truer processing program.

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