Chamfering device for wafer

Abstract

To provide a chamfering device for a wafer that is configured to enable truer preparation grinding stones to be easily replaced and adjusted due to end of a service life and to be applied to various kinds.SOLUTION: A chamfering device for a wafer, which is configured to subject a grinding stone 16 to truing using a truer 10 and to grind an edge part at an outer periphery of a wafer W using the grinding stone 16 subjected to truing, comprises: truer preparation grinding stones 15 that prepare an edge shape of the truer 10 in accordance with a truer processing program 50; a discoid fixed circular plates 31 having a plurality of truer preparation grinding stones 15 installed at an outer periphery part; and a control part 30 that controls processing conditions of the truer preparation grinding stones 15, the truer 10 and the grinding stone 16, where the control part 30 rotates and stops the fixed circular plate 31, so that the truer preparation grinding stones 15 are switched.SELECTED DRAWING: Figure 2

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 a semiconductor wafer, 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] In order to easily true the groove shape of a chamfering grindstone used in a chamfering device for plate-like objects to a desired shape, it is known that the groove shape of a master grindstone is transferred to the outer periphery of the truing grindstone, and the outer periphery shape of this truing grindstone is transferred to the chamfering grindstone, thereby forming grooves in the chamfering grindstone, as described in Patent Document 1, for example.

[0007] Patent Document 2 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 groove accuracy of the wafer grinding wheel formed by the truer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-153085 [Patent Document 2] Japanese Patent Application Publication No. 2018-167331 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 above-mentioned conventional technology requires a truer-making grindstone to make the edge of the truer using a truer processing program. However, the truer-making grindstone is usually a dedicated grindstone groove with a fixed shape that is attached to the grindstone for rough peripheral grinding. In other words, since the grindstone for rough peripheral grinding shares the same shaft as the truer-making grindstone, it is difficult to increase the number of grooves due to storage space limitations, and throughput has to be reduced.

[0011] Furthermore, since the fixed-shape Truer grinding wheels continue to grind at specific parts of the grinding groove, the grinding grooves become deformed due to wear and tear, and no longer meet the design specifications, resulting in the wheels reaching the end of their lifespan sooner. Replacing Truer grinding wheels requires adjustment and other maintenance, which increases costs.

[0012] The object of the present invention is to solve the problems of the prior art and to provide a wafer chamfering device for processing the outer edge portion of a semiconductor wafer, which facilitates adjustment when a truer manufacturing grinding wheel is replaced due to its lifespan, enables handling of a wide variety of products, reduces downtime and improves throughput, and ultimately improves shipping quality such as tolerances for wafer accuracy and variations, even for materials that are difficult to process. [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 plate-shaped fixed plate on which a plurality of truer making grinding wheels are installed; and a control unit that controls the processing conditions of the truer making grinding wheels, the truer, and the grinding wheel, and the truer making grinding wheels are switched by moving and stopping the fixed plate via the control unit.

[0014] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer manufacturing grindstone is switched in accordance with the target shape of the truer.

[0015] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer manufacturing grindstone is switched in accordance with the life of the truer manufacturing grindstone.

[0016] Furthermore, in the above-described wafer chamfering device, it is preferable to include a truer-prepared grindstone evaluation unit that measures the edge shape of the truer and evaluates the truer-prepared grindstone, and to switch the truer-prepared grindstone based on the evaluation.

[0017] 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 manufacturing grinding wheel is selected and the grinding wheel groove shape is created based on the learning model.

[0018] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer manufacturing grindstones are used in combination with a rough cutting truer manufacturing grindstone and a target shape manufacturing truer manufacturing grindstone to manufacture the edge shape of the truer.

[0019] Furthermore, in the above-described wafer chamfering device, it is preferable that the truer-making grindstone is mounted in a grindstone cartridge and placed on the outer periphery of the fixed plate.

[0020] Furthermore, in the above-described wafer chamfering device, it is preferable that the grindstone cartridge is replaced by the control unit. [Effects of the Invention]

[0021] According to the present invention, adjustments required for replacement of a truer manufactured grinding wheel due to its lifespan can be simplified, a wide variety of products can be handled, downtime can be reduced, and throughput can be improved. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a top view of a truer making unit according to one embodiment of the present invention; [Figure 2] 1A and 1B are perspective and side views of a truer making unit of a chamfering device according to an embodiment; [Figure 3] FIG. 1 is a block diagram showing the overall system configuration of a chamfering device according to an embodiment. [Figure 4] An explanatory diagram showing the processing procedure for grinding the chamfered portion of the wafer edge [Figure 5] Cross-sectional view of Truer and Truer-made grinding wheels [Figure 6] FIG. 10 is a side view showing the configuration of a machine shaft in creating an edge shape of a truer according to one embodiment. [Figure 7] 1 is a control flowchart of a wafer chamfering device according to an embodiment. [Figure 8] An explanatory diagram showing the edge shape creation of the truer (Example 1 of the creation of the upper and lower side widths) [Figure 9] 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 10] An explanatory diagram showing the creation of the edge shape of the truer (an example of creating a flat width) [Figure 11] An explanatory diagram showing the creation of the edge shape of the truer (example of creating an upper tip radius R1 and a 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 edge shape creation of the truer (when the target shape of the truer roughly matches the groove shape of the grinding stone used to create the truer) [Figure 14] An explanatory diagram showing the edge shape creation of the truer (when the target shape of the truer differs from the groove shape of the grinding wheel used to create the truer) [Figure 15] An explanatory diagram showing how to create the edge shape of a truer (when using a rough cutting truer creation grindstone) [Figure 16] An explanatory diagram showing the edge shape creation of the truer (after processing with the truer creation grindstone for rough cutting) [Figure 17] An explanatory diagram showing the processing procedure of the Trua using the Trua processing program (Example 1) [Figure 18] An explanatory diagram showing the processing procedure of Trua using the Trua processing program (Example 2) DETAILED DESCRIPTION OF THE INVENTION

[0023] Fig. 1 is a top view of a truer making unit according to an embodiment of the present invention, Fig. 2 is a perspective view and a side view thereof, and Fig. 3 is a block diagram showing the overall system configuration of a chamfering device according to an embodiment. FIG. 4 is an explanatory diagram showing a processing procedure for grinding the chamfered portion of the wafer edge surface.

[0024] As shown in Fig. 4, the chamfering process is performed by first grinding the edge shape of the truer 10 with 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 with the grinding wheel 16.

[0025] In Figure 4, 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 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 (see Figure 3).

[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, truing requires the amount of cut into the grinding wheel 16 as a condition, so the diameter of the grinding wheel groove in 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 moving and grinding the edge of the truer 10 relative to the truer making grinding wheel 15 (using a machine axis attached to the table that fixes the workpiece). The environment in which the truer making grinding wheel 15 is installed is one in which coolant, fallen abrasive grains, chips, etc. are present, making it difficult to directly measure the shape of the grinding grooves of the truer making grinding wheel 15. It is preferable that the truer making grinding wheel 15 be determined to have 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] A chamfering device according to one embodiment prepares a plurality of types of truer manufacturing grindstones 15 and can manufacture a wide variety of truers 10 by switching to the optimum truer manufacturing grindstone 15 depending on the target shape of the truer 10 that will be the workpiece. To achieve this, it is preferable to make the truer manufacturing grindstones 15 replaceable by attaching them to grindstone cartridges 32, as shown in Fig. 2. Note that Fig. 2 does not show the grindstone groove shape (truer manufacturing grindstones 15) of the grindstone cartridge 32 attached to the fixed disc 31.

[0031] As shown in Fig. 1, multiple truer-making grindstones 15 are attached to grindstone cartridges 32 and installed on the outer periphery of a circular fixed disk 31. The truer-making grindstones 15 used to process the truer 10 are selected and switched from the multiple truer-making grindstones 15 by rotating and stopping the fixed disk 31. Here, the fixed disk 31 is illustrated and described as having a disk-like shape, but is not limited to a disk-like shape and may be simply plate-like. Therefore, a plate-like fixed plate, not just a fixed disk, is also within the scope of the present invention, and the term "fixed plate" as used herein includes both the fixed disk 31 and a plate-like fixed plate. Furthermore, the grindstone cartridges 32 may be installed on the plate-like fixed plate not only on the outer periphery but also in an overlapping or non-overlapping (staggered) configuration in the upward direction (Z-axis direction). Thus, the installation location of the grindstone cartridges 32 on the fixed plate is not limited to the example described in the present invention, and may be any location as long as a specific truer-making grindstone 15 can be selected to machine the truer 10. A case where the fixed disk 31 is not disk-shaped but simply plate-shaped, for example, square, will be described. When the fixed disk 31 is a square fixed plate, when selecting a desired one from among the truer-made grindstones 15 attached to the grindstone cartridges 32 installed on the outer periphery of this fixed plate, the side of the fixed plate on which the desired truer-made grindstone 15 is attached is rotated so as to face the truer, and the truer-made grindstone 15 and the truer 10 are moved relatively to position the truer-made grindstone 15 and the truer 10 in a position where they face each other, thereby selecting and switching the desired truer-made grindstone 15. Therefore, in the present invention, the movement of the fixed plate includes not only movement in the X, Y, and Z axis directions but also rotation.

[0032] FIG. 1 shows a Truer-made grinding wheel 15 in which multiple grinding wheel cartridges 32 are arranged along the outer periphery of a fixed disk 31. However, the configuration of the Truer-made grinding wheel 15 is not limited to the above. Instead of being replaceable like the grinding wheel cartridges 32, the Truer-made grinding wheel 15 may have (non-removable) protrusions corresponding to the grinding wheel cartridges 32 along the outer periphery of the fixed disk 31. In this case, each protrusion may be individually attached to the fixed disk 31, or an annular grinding wheel configured like a gear in plan view may be attached to the fixed disk 31. In this case, each gear tooth corresponds to a protrusion. Different shaped grinding wheel grooves (Truer-made grinding wheels 15) are pre-formed on each protrusion, and the desired shape of grinding groove can be selected and switched by rotating and stopping the fixed disk 31, just as in the case of using grinding wheel cartridges.

[0033] Furthermore, the selection of the truer-manufactured grinding wheel 15 for the target shape of the truer 10 and the creation of the grinding wheel groove shape of the truer 10 are performed by modeling using analytical methods, statistical methods, machine learning, etc. At that time, the change in the shape of the grinding wheel groove of the truer-manufactured grinding wheel 15 is determined from the edge shape of the truer 10 that is the workpiece. The truer-manufactured grinding wheel evaluation unit 39 evaluates the change in shape of the truer-manufactured grinding wheel 15 due to wear, 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-manufactured grinding wheel 15.

[0034] Since the multiple grinding stone cartridges 32 are provided with multiple types of Truer-made grinding stones 15-1, 15-2, 15-3 with different shapes, multiple types of Truers 10-1, 10-2, 10-3 with different shapes can be made. It is preferable that the switching of the Truer-made grinding stone 15 to be used or the replacement of the grinding stone cartridge 32 be automatically performed by the control unit 30 according to the lifespan and type of the Truer-made grinding stone 15. The number of types of Truer-made grinding stones and Truers prepared is not limited to three, and may be more or less.

[0035] Furthermore, it is possible to increase the number of fixed disks 31 that can be mounted in multiple stages. The Truer-made grinding wheel 15 can be easily replaced and adjusted depending on its lifespan, and can be used for a wide variety of products, which reduces downtime of the wafer chamfering device and improves throughput.

[0036] The chamfering device evaluates and predicts deformation of the truer-making grinding wheel 15 due to wear, etc., by using shape evaluation that compares the edge shape of the truer 10 made by the truer-making 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.

[0037] 5 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 flat surface width X3, an upper tip radius R1, and a lower tip radius R2. In the description of the present invention, the upper side width X1, the lower side width X2, the truer plane width X3, the upper tip radius R1, and the lower tip radius R2 may be used to indicate the surface of the corresponding portion. For example, the upper side width X1 may be used to indicate the surface of the truer 10 indicated by the dimension X1 in Figure 5. The same applies to the lower side 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.

[0038] 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.

[0039] 6 is a side view showing the configuration of the machine axes in manufacturing the edge shape 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 θ W The truer 10 rotates around the pitch axis, but the movement directions of the X and Z axes do not change. The truer making grindstone 15 is mounted on a workpiece moving table 25-2 that can rotate around a fixed disk rotation axis. The truer 10 side may also have a four-axis configuration, omitting the pitch axis.

[0040] 3, 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.

[0041] The fixed disk 31, on which multiple grinding stone cartridges 32 are installed, is rotated and stopped by the control unit 30, and the control unit 30 switches the attached truer-manufactured grinding stone 15 based on the target shape, evaluation by the truer-manufactured grinding stone evaluation unit 39, prediction of the grinding stone groove, etc.

[0042] To process the truer 10, the truer making grindstone 15 is fixed to the fixed disc 31, while the truer 10 is fixed to a work fixing part 24 placed on a work moving table 25 that is rotatable around a rotation axis (θ) and movable in the X, Y, and Z axis directions. The truer 10 fixed to the work fixing part 24 is moved in the X, Y, and Z axis directions while rotating around the rotation axis (θ), and the truer 10 is machined by giving cuts to the truer making grindstone 15. On the other hand, to process the wafer W, a grinding wheel 16 is attached to the grinding wheel spindle 17, and the wafer W is placed on a vacuum chuck table fixed to the workpiece fixing part 24. The wafer W is rotated about a rotation axis (θ) while being moved along the X, Y, and Z axes, and is processed by the rotating grinding wheel 16 giving it cuts.

[0043] 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).

[0044] 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.

[0045] The stored results are constructed as a learning model 38. The learning model 38 is obtained as a machining learning model 38-1, 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 (see Figure 7).

[0046] The truer processing program 50 is created to maximize the life of the truer fabrication grinding wheel 15 based on a learning model 38 that shows 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 fabrication grinding wheel 15, and the truer processing program 50. Updating and creating the truer processing program 50, selecting the truer fabrication grinding wheel 15, and creating the grinding wheel groove shape based on the learning model 38 to maximize the life of the truer fabrication grinding wheel 15 reduces the frequency of replacement of the truer fabrication grinding wheel 15, reducing the frequency of switching between the truer fabrication grinding wheel 15 and enabling more efficient operation.

[0047] However, depending on the operating conditions, it may be preferable to operate the truer 10 without measuring the edge shape. In that case, the evaluation of the change in the shape of the grinding wheel groove of the truer-made grinding wheel 15 and the lifespan may be performed by finding a correlation when creating the processing condition database 37 or as a result of learning.

[0048] FIG. 7 is a control flowchart of the wafer chamfering device. 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, which have been determined in advance, and the truer processing program 50 is created and updated with the chamfering angles such as the upper surface angle θ1 and the lower surface angle θ2 of the end face shown in FIG. 4 (Step S1).

[0049] The Truer processing program 50 reflects the cross-sectional shapes of the edge portions of the Truer 10 and grinding wheel 16 measured by the shape measurement unit 35 (see Figure 3) 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.

[0050] 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 edge shape of the manufactured truer 10 is measured by the shape measuring unit 35 (step S3).

[0051] 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.

[0052] 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).

[0053] 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).

[0054] 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 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 created as a database.

[0055] 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 the learning model 38, and evaluates the Truer-manufactured grinding wheel 15 based on the learning model 38, selects the Truer-manufactured grinding wheel 15, and creates the grinding wheel groove shape. The Truer machining program 50 is created and updated based on the evaluation of changes in the shape of the Truer-manufactured grinding wheel 15 by the Truer-manufactured grinding wheel evaluation unit 39. For example, if the Truer-manufactured grinding wheel evaluation unit 39 evaluates that the Truer-manufactured grinding wheel 15 has deformed due to wear or the like, it updates the Truer machining program 50 or switches the Truer-manufactured grinding wheel 15.

[0056] 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.

[0057] The explanation in Figure 7 has 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.

[0058] The method for evaluating the Truer manufactured grindstone 15 by the Truer manufactured grindstone evaluation unit 39 is as follows: (1) First method: Judging from the measurement results of the wafer W shape after grinding (step S6 in FIG. 7) (without measuring the edge shape of the truer 10) (2) The second method is to judge from the measurement results of the manufactured true edge shape (step S3 in FIG. 7). Either of the above, or a combination of the first and second methods, will be used.

[0059] 8 to 11 are explanatory diagrams showing the manufacturing of the edge shape of the truer 10, that is, showing the grinding process of the truer 10 using the truer manufacturing grindstone 15. Fig. 8 is manufacturing example 1 of the upper side width X1 and lower side width X2 of the truer 10, Fig. 9 is manufacturing example 2 of the upper side width X1 and lower side width X2 of the truer 10, Fig. 10 is manufacturing example of the truer plane width X3, and Fig. 11 is manufacturing example of the upper tip radius R1 and lower tip radius R2.

[0060] 8 shows a case where the truer 10 is not rotated around the pitch axis (see FIG. 6) 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 around the axis at a speed of θ t Grinding is performed by the contact surfaces of the truer 10 and truer-made grinding wheel 15 moving relatively in the direction of the arrow in Figure 8 while rotating around the axis as the center of rotation. 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 escape is performed), and the movement speeds in X, Y, and Z.

[0061] 9 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.

[0062] FIG. 10 shows that grinding is performed by relatively moving the truer making grindstone 15 and the truer 10 so that the plane width X3 of the truer 10 moves in the direction of the arrow.

[0063] 11 shows that the upper tip radius R1 of the truer 10 is ground by slightly rotating the truer 10 in the direction of the arrow around the pitch axis using the upper slope CX1 of the truer making grinding wheel 15. Note that a similar method is used when grinding the lower tip radius R2.

[0064] 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.

[0065] For example, the truer machining program 50 may be configured to use the rotation axis (θ W While rotating the tool, the X and Z axes are moved by 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, spark-out time, X, Y, and Z movement speeds, and pitch axis rotation speed.

[0066] The tool path TP is optimized not only to reduce 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 .

[0067] For example, the Truer-manufactured grinding wheel evaluation unit 39 monitors the processing load to predict and identify unevenly worn parts of the Truer-manufactured grinding wheel 15, and reflects the results in the Truer processing program 50 to maintain the design 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 processing uniform, without causing uneven distribution, is incorporated into the Truer processing program 50.

[0068] Fig. 13 is an explanatory diagram showing the creation of the edge shape of the truer 10 when the target shape of the truer 10 approximately matches the groove shape of the truer-making grindstone 15, and Fig. 14 is an explanatory diagram showing the creation of the edge shape of the truer 10 when the target shape of the truer 10 differs from the groove shape of the truer-making grindstone 15. As shown in Fig. 15, when the slope of the upper side surface width X1, which is the target shape of the truer 10, and the slope of the upper slope CX1 of the truer-making grindstone 15 approximately match, the amount of grinding can be reduced and the processing time can be shortened.

[0069] On the other hand, as shown in Fig. 14, if the slope of the upper side surface width X1, which is the target shape of the truer 10, differs from the slope of the upper slope CX1 of the truer manufacturing grindstone 15, it is necessary to perform rough cutting at the beginning of processing and then correct the slope. Therefore, it is advantageous for shortening the processing time if the truer manufacturing grindstone 15 has a shape that is close to the target shape of the truer 10 in advance. In other words, as explained in Figs. 1 and 2, by preparing multiple types of truer manufacturing grindstones 15 and switching to the optimal truer manufacturing grindstone 15 depending on the target shape of the truer 10, it is possible to shorten the processing time and improve throughput.

[0070] Fig. 15 is an explanatory diagram showing the edge shape of the truer 10 when using the rough cutting truer manufacturing grindstone 15-4, and Fig. 16 is an explanatory diagram showing the edge shape of the truer 10 after processing with the rough cutting truer manufacturing grindstone 15-4. In the above embodiment, multiple types of truer manufacturing grindstones 15 can be prepared, so it is easy to manufacture the edge shape of the truer 10 by using both the rough cutting truer manufacturing grindstone 15-4 and the truer manufacturing grindstone 15 for manufacturing the target shape (typically by switching between and using the two types of grindstones).

[0071] The rough cutting truer making grindstone 15-4 adjusts the diameter D and rough shape of the truer 10, and is preferably a formed groove, so that minimizing the amount of subsequent processing can be prioritized over shape accuracy, surface roughness, etc. The truer making grindstone 15 for creating the target shape prioritizes shape accuracy, surface roughness, etc. By selectively using the rough cutting truer making grindstone 15-4 and the truer making grindstone 15 for creating the target shape, not only can processing time be shortened and precision increased, but the life of the truer making grindstone 15 can also be extended.

[0072] 17 and 18 are explanatory diagrams showing the machining procedure of the truer 10 according to the truer machining program 50. As explained in Fig. 8 to Fig. 11, the machining procedure of the truer 10 does not always have to be the same procedure and can be changed. The change in machining procedure and the switching of the truer-manufactured grindstone 15 are performed based on the evaluation of the truer-manufactured grindstone evaluation unit 39, and the portions of the truer-manufactured grindstone 15 used for machining can be made uniform without being unevenly distributed.

[0073] Example 1 in FIG. 17 will be described. The truer 10 is ground by feeding the truer plane width X3 (see Figure 5) of the truer making grindstone 15 as shown by the arrow on the plane CX3 (see Figure 5) to produce the diameter D of the truer 10 (Step 1). Create the upper tip radius R1 of the truer 10 (see Figure 5). (Step 2) The upper side width X1 of the truer 10 (see Figure 5) is prepared (Step 3). Adjust and correct the shape of the upper side width X1 and the upper tip radius R1 (Step 4). Adjust and correct the diameter D of the Truer 10 to finish. (Step 5) Step 6: Create the radius R2 (see Figure 5) at the bottom of the truer 10. The width X2 of the bottom surface of the truer 10 (see Figure 5) 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.

[0074] Example 2 of FIG. 18 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') Create the diameter D of the truer 10. (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') Adjust and correct the lower tip radius R2, diameter D, upper tip radius R1, and upper surface width X1. (Step 8') Thereafter, steps 1' to 8' are repeated several times to create and finish the edge shape of the truer 10.

[0075] 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.

[0076] However, the parts other than the worn parts are still usable. Therefore, the processing of the truer 10 by the truer processing program 50 is not always performed in the same procedure, but is changed so as to prevent uneven wear, thereby making it possible to maximize the life of the truer making grindstone 15.

[0077] 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.

[0078] The truer manufacturing grindstone evaluation unit 39 predicts and determines when the truer manufacturing grindstone 15 has reached the end of its life. When the truer manufacturing grindstone 15 has reached the end of its life, the control unit 30 (see FIG. 3) automatically switches to a new groove based on the evaluation by the truer manufacturing grindstone evaluation unit 39, or prompts the operator to switch grooves or replace the grindstone by issuing an alarm, etc., and then switches to a new groove, thereby creating the edge shape of the truer 10. Therefore, the above-mentioned wafer chamfering device makes it easy to replace and adjust the truer manufacturing grindstone 15 when it reaches the end of its life, can accommodate a wide variety of products, and can reduce downtime and improve throughput. [Explanation of symbols]

[0079] 10...Tsurua 15...Tsurua manufactured whetstone 15-4...Trua-made grinding stone for rough cutting 16...Grinding wheel 17...Grinding wheel spindle 18...Quill 24...Workpiece fixing part 25, 25-1, 25-2...Work moving table 30...Control unit 31...Fixed disc 32...Grinding stone cartridge 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 plate-shaped fixing plate on which a plurality of the Trua manufactured grindstones are installed; a control unit for controlling the processing conditions of the truer manufacturing grindstone, the truer, and the grinding stone; wherein the truer manufacturing grindstone is switched by moving and stopping the fixed plate by the control unit.

2. 2. The wafer chamfering device according to claim 1, wherein the truer manufacturing grindstone is switched depending on the target shape of the truer.

3. 2. The wafer chamfering device according to claim 1, wherein the truer-preparing grindstone is switched in accordance with the life of the truer-preparing grindstone.

4. 2. The wafer chamfering device according to claim 1, further comprising a truer-prepared grindstone evaluation unit that measures the edge shape of the truer and evaluates the truer-prepared grindstone, and the truer-prepared grindstone is switched based on the evaluation.

5. 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, further comprising: a grinding wheel for making the truer and a grinding wheel groove shape are selected based on the learning model.

6. 2. The wafer chamfering device according to claim 1, wherein the truer manufacturing grindstones are used in combination with a rough cutting truer manufacturing grindstone and a target shape manufacturing grindstone to manufacture the edge shape of the truer.

7. 2. The wafer chamfering device according to claim 1, wherein the truer grindstone is mounted in a grindstone cartridge and placed on the outer periphery of the fixed plate.

8. 8. The wafer chamfering apparatus according to claim 7, wherein the replacement of the grindstone cartridge is performed by the control unit.

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