Chamfering device for wafer and chamfering method

Abstract

To provide a chamfering device for a wafer that can efficiently maintain a quality of a wafer (a semiconductor material substrate) that is a final product, so as to boost yield.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: a truer preparation grinding stone 15 that prepares an edge part of the truer 10; a shape measuring part 35 that measures a cross-section shape of the wafer; a control part 30 that controls processing conditions of the truer preparation grinding stone 15, the truer 10 and the grinding stone 16; and a service-life determining part 40 for determining a service life of the truer preparation grinding stone 15, that makes the shape measuring part 35 measure the cross-section shape of the wafer W processed by the grinding stone 16 (S6) and determines a service life of the truer preparation grinding stone 15 by comparing the cross-section shape with a target shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer chamfering device and chamfering method in which a peripheral precision grinding wheel (grinding wheel) having a groove shape used in a chamfering device for the end face of a semiconductor wafer is transferred (trued) by a truer, and the transferred peripheral precision grinding wheel is used 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 the truer in order to improve the transfer rate and processability as well as the accuracy of the groove shape of the wafer grinding wheel formed 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, in the above-mentioned conventional technology, a truer making grindstone is required to make the edge portion of the truer, but the truer making grindstone itself wears out when making the truer, and its shape changes from the initial design value depending on the number of times it is used, etc., which can deteriorate the accuracy of creating the edge shape of the truer, and no consideration was given to the lifespan of the truer making grindstone (the limit of shape change that can maintain shape creation accuracy).

[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 improves the precision and quality of the grooved grinding wheels used in the wafer chamfering device by improving the precision of truing, and ultimately improves the shipping quality of wafers, such as the allowable precision and variation, even for materials that are difficult to process. [Means for solving the problem]

[0013] In order to achieve the above 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 wafer chamfering device comprising: a truer-making grinding wheel that makes the edge of the truer; a shape measuring unit that measures the cross-sectional shape of the wafer; a control unit that controls the truer-making grinding wheel and the processing conditions of the truer and the grinding wheel; and a truer-making grinding wheel life judgment unit that measures the cross-sectional shape of the wafer machined with the grinding wheel using the shape measuring unit and compares it with a target shape to judge the life of the truer-making grinding wheel.

[0014] Furthermore, in the above-mentioned wafer chamfering device, it is preferable to include a processing condition database in which the processing conditions and the measurement results of the shape measurement unit after truing are stored in association with each other, and a learning model constructed from the processing condition database, and the truer manufacturing grinding wheel life determination unit determines the life of the truer manufacturing grinding wheel based on the learning model.

[0015] Furthermore, in the above-mentioned wafer chamfering device, it is preferable that the truer manufacturing grindstone life judgment unit measures the edge shape of the truer using the shape measurement unit, and judges that the truer manufacturing grindstone has reached the end of its life if the allowable shape accuracy is not met.

[0016] Furthermore, in the above-described wafer chamfering device, it is preferable that the life determination unit for the truer-manufacturing grindstone transfers the groove shape of the truer-manufacturing grindstone onto a transfer wafer and determines the shape of the truer-manufacturing grindstone.

[0017] Furthermore, in the above-described wafer chamfering device, it is preferable that the life judgment unit for the truer manufacturing grindstone compares the cross-sectional shape of the wafer machined by the grinding wheel with the target shape, and if it is found that the allowable shape accuracy is not met, it performs the truing, grinds the wafer, and judges the target shape again, and if the allowable shape accuracy is met, it judges that the truing was defective, and if the allowable shape accuracy is not met, it performs the manufacturing of the truer, the truing, grinds the wafer, and judges the target shape again with the truer manufacturing grindstone, and if the allowable shape accuracy is met, it judges that the manufacturing of the truer was defective, and if the allowable shape accuracy is not met, it judges that the truer manufacturing grindstone has reached the end of its life.

[0018] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer manufacturing grindstone life determination unit measures the edge shape of the truer using the shape measurement unit, and if it is determined that the allowable shape accuracy is not met, manufactures the truer and measures the shape of the truer again, and if the allowable shape accuracy is met, determines that the manufacture of the truer was defective, and if the allowable shape accuracy is not met, determines that the truer manufacturing grindstone has reached the end of its life.

[0019] Furthermore, in the above-described wafer chamfering device, the transfer wafer is preferably a Si wafer.

[0020] Furthermore, in the above-mentioned wafer chamfering device, it is preferable that a plurality of transfer wafers are used. In order to achieve the above object, the present invention is a wafer chamfering method using a wafer chamfering device, comprising the steps of: a life determination unit for the truer manufacturing grindstone, when comparing the cross-sectional shape of the wafer machined by the grinding wheel with the target shape and finding that it does not satisfy the allowable shape accuracy, performing the truing, grinding the wafer, and judging the target shape again; a step of determining that the truing was defective if the allowable shape accuracy is satisfied; a step of using the truer manufacturing grindstone to once again manufacture the truer, perform the truing, grind the wafer, and judge the target shape if the allowable shape accuracy is not satisfied; a step of determining that the manufacture of the truer was defective if the allowable shape accuracy is satisfied; and a step of determining that the truer manufacturing grindstone has reached the end of its life if the allowable shape accuracy is not satisfied. [Effects of the Invention]

[0021] According to the present invention, the life of the truer manufacturing grindstone can be determined, so that a wafer chamfering device can be obtained that efficiently maintains the quality of the final product, the wafer (semiconductor material substrate), and improves the yield. [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] Control flowchart showing the first method by the Truer manufacturing grindstone life determination unit [Figure 5] An explanatory diagram showing the first precondition of the Truer manufactured grinding wheel life judgment unit [Figure 6] An explanatory diagram showing the second prerequisite for the Truer manufactured grinding wheel life judgment unit [Figure 7] An explanatory diagram showing the third prerequisite for the Truer manufactured grinding wheel life judgment unit [Figure 8] Flowchart showing the determination by the first method of the truer manufactured grinding wheel life determination unit [Figure 9] Control flowchart showing the second method by the Truer manufacturing grindstone life determination unit [Figure 10] Flowchart showing the determination by the second method of the Truer manufactured grinding wheel life determination unit [Figure 11] Control flowchart showing the third method by the Truer manufacturing grindstone life determination unit [Figure 12] 3 is an explanatory diagram of a transfer method from the truer manufacturing grindstone 15 to the wafer W according to the third method. [Figure 13] Flowchart showing the determination by the third method of the Truer manufactured grinding wheel life determination unit 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, in the chamfering process, first, the edge shape of the truer 10 is ground by a truer making grindstone 15. Next, the groove shape of the grinding wheel 16 is transferred (trued) by the truer 10. Furthermore, the outer peripheral shape of the wafer W is ground by 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] Furthermore, taking into consideration 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] In the truer fabrication process, the edge of the truer 10 is moved relative to the truer fabrication grinding wheel 15 (using a machine axis attached to the table that secures the workpiece) and ground to create a desired arbitrary shape. The environment in which the truer fabrication grinding wheel 15 is installed is an environment where coolant, fallen abrasive grains, swarf, etc. are present, making it difficult to directly measure the shape of the grinding wheel grooves of the truer fabrication grinding wheel 15. It is preferable to determine that the truer fabrication 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 in one embodiment has the function of accurately determining when a change in the shape of the grinding groove of the truer manufacturing grinding wheel 15 exceeds the allowable value for the accuracy of creating the edge shape of the truer 10 that will be the workpiece (allowable shape accuracy of the truer 10), and prompting the user to switch the grinding groove or replace the truer manufacturing grinding wheel 15.

[0031] That is, the chamfering device according to one embodiment judges the life of the truer-making grindstone 15 using a shape evaluation that compares the edge shape of the truer 10 made by the truer-making grindstone 15 and the edge shape of the wafer W processed by the grinding wheel 16 transferred using the truer 10 with a target shape. Furthermore, this judgment is made by machine learning the relationship between the edge shape of the truer 10, the grinding wheel 16, and the edge shape of the wafer W.

[0032] However, depending on the operating conditions, it may be preferable to operate without measuring the edge shape of the truer 10. In this case, the life of the truer making grindstone 15 may be determined by finding a correlation between a predetermined number of truer makings and the lifespan based on the results of learning or time in the processing condition database 37, and determining that the lifespan has been reached when the predetermined number of truer makings has been reached.

[0033] 2, the control unit 30 controls, as processing conditions, the cutting depth, rotation speed, position, movement amount, etc. of the truer making grindstone 15, the truer 10, and the grinding stone 16. 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.

[0034] A grinding wheel 16 serving as a tool is attached to the grinding wheel spindle 17. Similarly, a truer-made grinding wheel 15 may also be attached to the grinding wheel spindle 17. The truer-made grinding wheel 15 may also be attached to a separate spindle. On the other hand, the wafer W and truer 10, which are the workpieces, are placed on a workpiece moving table 25 and fixed to a workpiece fixing section 24 consisting of a vacuum chuck table, and are capable of moving in the X-axis, Y-axis, and Z-axis directions and rotating around a rotation axis (θ).

[0035] 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).

[0036] The machining condition database 37 stores the results of monitoring the cutting depth, rotation speed, position, movement amount, machining load, displacement, vibration, machining heat, etc. as machining conditions for the truer 10 and grinding wheel 16, in association with the measurement results of the shape measurement unit 35 after truing. 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.

[0037] 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 is started with the upper surface angle θ1, the lower surface angle θ2, and the chamfering angles of the end faces shown in Figure 3 as shown (Step S1).

[0038] The truer machining program reflects the cross-sectional shapes of the edge portions of the truer 10 and grinding wheel 16 measured by the shape measuring unit 35 before machining, the machining condition database 37, the machining learning model 38-1, and the analysis-based machining model 38-2.

[0039] The edge shape of the truer 10 is produced by grinding with the truer production grindstone 15 according to the truer processing program (step S2). The edge shape of the manufactured truer 10 is measured by the shape measuring unit 35 (step S3). However, when the life of the truer manufacturing grindstone 15 is determined from the measurement results of the edge shape of the wafer W after grinding, it is not necessary to measure the edge shape of the truer 10.

[0040] 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 during processing of the truer 10 and grinding wheel 16, as well as the temperature and heat flow measurement unit, are monitored during truing.

[0041] 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).

[0042] If the wafer W ground by the grinding wheel 16 does not fall 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).

[0043] The processing condition database 37 is created by associating the results of monitoring the processing conditions during truing (step S4) and during outer periphery grinding of the wafer W (step S5) with the truer processing program, 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 created as a database.

[0044] The Truer-manufactured grinding wheel life judgment model 39 is constructed from the machining learning model 38-1, the analysis-based machining model 38-2, etc. The Truer-manufactured grinding wheel life judgment unit 40 evaluates the change in shape of the Truer-manufactured grinding wheel 15 by comparing it with a target shape based on the Truer-manufactured grinding wheel life judgment model 39, and judges the life of the Truer-manufactured grinding wheel 15.

[0045] When the Truer-made grindstone life determination unit 40 determines that the Truer-made grindstone 15 has reached the end of its life, an alarm is issued at that point to interrupt processing and prompt the user to replace the Truer-made grindstone 15. In step S1, the Truer processing program is executed via the Truer-made grindstone life determination unit 40.

[0046] 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 inputs queries to the machining learning model 38-1 as needed 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 reducing shape variation.

[0047] 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, it is also possible to machine the upper or lower part of the groove to be formed in the grinding wheel 16 with the truer 10, 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.

[0048] The method for evaluating the shape of the Truer manufactured grindstone 15 by the Truer manufactured grindstone life determination unit 40 is as follows: (1) First method: Judging from the measurement results of the wafer W shape after grinding (step S6 in FIG. 1) (without measuring the edge shape of the truer 10) (2) A second method of measuring and judging the edge shape of the manufactured truer 10 (step S3 in FIG. 1). (3) Either the third method, in which the groove shape of the truer-fabricated grinding wheel 15 is transferred to multiple transfer wafers (Si wafers L), and the edge shape of the transferred Si wafers L is measured to determine the shape of the truer-fabricated grinding wheel 15, or a combination of the first to third methods is used.

[0049] 4 is a portion of a control flowchart showing a first method by the truer manufacturing grindstone life determination unit 40 (steps S1 to S6 of FIG. 1). In step S1, the truer processing program is executed via the truer manufacturing grindstone life determination unit 40. Step S2 is carried out in the same manner as in FIG. 1, but step S3 is not executed because the life of the truer manufacturing grindstone 15 is determined from the measurement results of the edge shape of the wafer W after grinding. Thereafter, steps S4 to S7 are carried out in the same manner as in FIG. 1.

[0050] 5 is an explanatory diagram showing a first precondition of the truer manufacturing grindstone life determination unit 40 according to the first method. To determine that the truer manufacturing grindstone 15 has not reached the end of its life, the precondition in step S2 is the current value, that is, the cumulative number of times N that the truer 10 has been ground by the truer manufacturing grindstone 15 up to this time. t However, the maximum value N tmax However, the maximum number of times that the edge shape of the truer 10 can be ground by the truer manufacturing grindstone 15 is N tmax is known from past performance etc.

[0051] 6 is an explanatory diagram showing the second precondition of the truer manufacturing grinding wheel life determination unit 40 according to the first method. The truer manufacturing grinding wheel 15 has not reached the end of its life and the trued grinding wheel 16 can grind the outer periphery of the wafer W if the current value, that is, the cumulative number N of times the wafer W has been ground by the grinding wheel 16 up to this time, is the maximum value N. max The following is required to be done:

[0052] 7 is an explanatory diagram showing the third precondition of the truer-prepared grinding wheel life determination unit 40 according to the first method. For the truer-prepared grinding wheel 15 to have not reached the end of its life and for truing of the grinding wheel 16 to be possible, the precondition for step S4 is that the current value of the grinding wheel groove diameter D of the grinding wheel 16 must be larger than the minimum grinding wheel groove diameter D0. The chamfering device sequentially calculates the grinding wheel groove diameter as a truing condition (amount of cutting into the grinding wheel).

[0053] 8 is a flowchart showing the judgment by the first method of the Truer-manufactured grindstone life judgment unit 40. If any of the above first to third prerequisite conditions is not met, the Truer-manufactured grindstone life judgment unit 40 immediately judges that the Truer-manufactured grindstone 15 has reached the end of its life and issues an alarm to indicate that the Truer-manufactured grindstone 15 should be replaced.

[0054] If the first to third prerequisites are met, the truer processing program (step S1) is started. After that, if the pass / fail judgment (step S6) of the target shape of the periphery-ground wafer W is performed and a NG result is generated, that is, if the allowable shape accuracy for the target shape is not met, the cause may not only be the life of the truer manufacturing grinding wheel 15, but also a defect in the truing process itself for the grinding wheel 16.

[0055] 8, the truer manufacturing grindstone life determination unit 40 determines whether the truer manufacturing grindstone 15 has reached the end of its life. In step S40-1, if an NG occurs in a wafer W whose outer periphery has been ground, it is confirmed whether the truing process itself is defective.

[0056] Therefore, in step S40-1, truing (step S4), grinding of the wafer W (step S5), and the cross-sectional shape of the wafer W are again performed by the shape measuring unit 35, and the measurement result after grinding is compared with the target shape to determine whether or not the allowable shape accuracy for the target shape is met (step S6). If the result is OK, that is, if the allowable shape accuracy is met, it is determined that the truing process (step S4) itself was defective, and grinding of the wafer W continues.

[0057] Step S40-1 is repeated if the wafer W after periphery grinding is found to be NG, that is, if the target shape judgment result shows that the allowable shape accuracy is not met, then step S40-2 is performed. In step S40-2, in order to confirm whether the process of making the truer 10 (step S2) itself is defective, the truer 10 is made again using the truer making grindstone 15 (step S2), truing (step S4), the wafer W is ground (step S5), and the shape of the wafer W is measured, and it is judged whether the allowable shape accuracy for the target shape is met (step S6).

[0058] As a result, if the result is OK, that is, if the tolerance for shape accuracy is satisfied, it is determined that the process of fabricating the truer 10 (step S2) itself was defective, and grinding of the wafer W continues.

[0059] If NG occurs again on the wafer W whose periphery has been ground in step S40-2, it is determined that the truer manufacturing grindstone 15 has reached the end of its life, an alarm is sounded to suspend processing, and replacement of the truer manufacturing grindstone 15 is recommended.

[0060] 9 shows a portion of a control flowchart (steps S1 to S6 in FIG. 1) illustrating a second method by the truer manufacturing grindstone life determination unit 40. In step S1, the truer processing program is executed via the truer manufacturing grindstone life determination unit 40. Steps S1 and S2 are carried out in the same manner as in FIG. 1, and step S3 is executed to determine the life of the truer manufacturing grindstone 15 from the measurement results of the manufactured truer edge shape. If the result of executing step S3 is that the shape of the truer 10 satisfies the allowable shape accuracy, steps S4 to S7 are carried out as shown in FIG. 1.

[0061] 10 is a flowchart showing the judgment by the second method in the truer manufacturing grindstone life judgment unit 40. The first precondition in FIG. 5 is satisfied. That is, the cumulative number of times N that the truer 10 has been ground by the truer manufacturing grindstone 15 up to this time is t However, the maximum value N tmaxThe following is executed: The result of measuring the truer edge shape (step S3) is input to the truer manufacturing grindstone life determination unit 40, which determines whether the shape of the truer 10 satisfies the allowable shape accuracy.

[0062] If the shape of the truer 10 is NG, that is, does not satisfy the allowable shape accuracy, step S40-2 checks whether the process of manufacturing the truer 10 (step S2) itself is defective by again manufacturing the truer 10 with the truer manufacturing grindstone 15 (step S2) and measuring the truer edge shape (step S3), and again determining whether the shape of the truer 10 satisfies the allowable shape accuracy. If the result is OK, that is, if the allowable shape accuracy is satisfied, it is determined that the manufacturing of the truer 10 (step S2) itself was defective, and grinding of the wafer W continues.

[0063] If the shape of the truer 10 is NG, that is, does not satisfy the allowable shape accuracy, step S40-2 determines that the truer-made grindstone 15 has reached the end of its life, issues an alarm to suspend processing, and prompts replacement of the truer-made grindstone 15.

[0064] 11 shows a portion of a control flowchart (steps S1 to S6 in FIG. 1) illustrating the determination by the third method in truer fabrication grindstone life determination unit 40. In the series of steps S1 to S7 excluding S3, if the determination of the pass / fail of the wafer W with respect to the target shape (step S6) results in an NG result, that is, if the allowable shape accuracy for the target shape is not met, truer fabrication grindstone life determination unit 40 determines the pass / fail of the groove shape of truer fabrication grindstone 15 in shape determination step S40-3 of truer fabrication grindstone 15. In this case, it is not necessary to fabricate the edge shape of truer 10 (step S2).

[0065] In the shape determination step S40-3 of the truer fabrication grinding wheel 15, the groove shape of the truer fabrication grinding wheel 15 is transferred to the Si wafer L that serves as the workpiece using the truer processing program, and the edge shape of the transferred Si wafer L is measured. The life of the truer fabrication grinding wheel 15 is determined as NG (groove shape defect) if the edge shape of the transferred Si wafer L is outside the allowable precision. Note that, since the thickness of the truer 10 is greater than that of the Si wafer L, the groove shape of the truer fabrication grinding wheel 15 is transferred to the Si wafer L using multiple Si wafers L, which are divided into upper, middle, and lower parts in the thickness direction.

[0066] 12 is an explanatory diagram of a transfer method from the truer fabrication grinding wheel 15 to the wafer W according to the third method. The transfer is performed using three Si wafers L (Lu, Lc, Ld) as workpieces, using parts (upper, central, and lower parts) of the grooves of the truer fabrication grinding wheel 15. The truer processing program (step S1) is used to grind the Si wafers L for the transfer.

[0067] However, in this case, the truer processing program (step S1) is divided in the thickness direction because the thickness of the truer 10 is greater than that of the wafer W. The upper Si wafer Lu is transferred with the upper shape of the truer manufacturing grinding wheel 15, the central Si wafer Lc is transferred with the central shape, and the lower Si wafer Ld is transferred with the lower shape.

[0068] 13 is a flowchart showing the judgment by the third method in the truer manufacturing grindstone life judgment unit 40. The first precondition in FIG. 5 is satisfied. That is, the cumulative number of times N that the truer 10 has been ground by the truer manufacturing grindstone 15 up to this time is t However, the maximum value N tmax The following is the execution:

[0069] In step S40-3 for determining the shape of the truer-fabricated grinding wheel 15, the groove shape of the truer-fabricated grinding wheel 15 is transferred to the Si wafer L, and the shape of the Si wafer L after transfer is determined. The shape of the Si wafer L after transfer is correlated in advance with the allowable shape accuracy of the truer 10, and the shape accuracy of the truer-fabricated grinding wheel 15 is determined.

[0070] If the result of the shape judgment is NG, that is, if the allowable shape accuracy is not met, step S40-3 determines that the truer-made grindstone 15 has reached the end of its life, issues an alarm to suspend processing, and prompts the truer-made grindstone 15 to be replaced. [Explanation of symbols]

[0071] 10...Tsurua 15...Tsurua manufactured whetstone 16...Grinding wheel 17...Grinding wheel spindle 18...Quill 24...Workpiece fixing part 25...Work moving table 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 life judgment model 40...Tsurua manufactured grinding wheel life judgment part 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 for making an edge portion of the truer; a shape measuring unit that measures a cross-sectional shape of the wafer; a control unit for controlling the processing conditions of the truer manufacturing grindstone, the truer, and the grinding stone; a life determination unit for the truer manufacturing grindstone that measures the cross-sectional shape of the wafer processed by the grinding wheel using the shape measurement unit and compares it with a target shape to determine the life of the truer manufacturing grindstone; A wafer chamfering device comprising:

2. a processing condition database in which the processing conditions and the measurement results of the shape measuring unit after the truing are stored in association with each other; a learning model constructed from the processing condition database; 2. The wafer chamfering device according to claim 1, wherein the truer manufacturing grindstone life determination unit determines the life of the truer manufacturing grindstone based on the learning model.

3. 3. The wafer chamfering device according to claim 1, wherein the truer manufacturing grinding wheel life judgment unit measures the edge shape of the truer using the shape measurement unit, and judges that the truer manufacturing grinding wheel has reached the end of its life if the allowable shape accuracy is not met.

4. 3. The wafer chamfering device according to claim 1, wherein the life determination unit for the truer-making grindstone transfers the groove shape of the truer-making grindstone onto a transfer wafer and determines the shape of the truer-making grindstone.

5. The truer manufacturing grindstone life determination unit measures the edge shape of the truer by the shape measurement unit, and if it is determined that the allowable shape accuracy is not met, manufactures the truer and measures the shape of the truer again, If the tolerance for shape accuracy is satisfied, it is determined that the truer was manufactured poorly; 4. The wafer chamfering apparatus according to claim 3, wherein if the allowable shape accuracy is not satisfied, it is determined that the truer manufacturing grindstone has reached the end of its life.

6. A method for chamfering a wafer using the wafer chamfering apparatus according to claim 1 or 2, comprising: a step in which the life determination unit of the truer manufacturing grinding wheel compares the cross-sectional shape of the wafer processed by the grinding wheel with the target shape, and when it is found that the cross-sectional shape does not satisfy the allowable shape accuracy, performs the truing again, grinds the wafer, and determines whether the cross-sectional shape satisfies the target shape; determining that the truing was defective if the allowable shape accuracy is satisfied; If the allowable shape accuracy is not satisfied, the truer is fabricated again using the truer fabrication grinding wheel, the truing is performed, the wafer is ground, and the target shape is determined; determining that the truer was manufactured poorly if the tolerance for shape accuracy is satisfied; and if the allowable shape accuracy is not satisfied, determining that the truer manufacturing grindstone has reached the end of its life.

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