Vine art forming method

Abstract

To provide a truer molding method that achieves reduction in time and cost required for formation of a truer and quality homogenization, and improves a trueing transfer rate, processability, and accuracy of a groove formed in the truer, in particular, further improves accuracy of an edge shape of the truer.SOLUTION: A truer molding method in trueing for forming a groove in a grindstone for grinding a chamfer part of a wafer by a disk-like truer includes: a process A in which a diameter and a rough shape of the truer are adjusted by a master grindstone for molding the truer; and a process B in which an edge of the truer is molded into a target shape. The process A and the process B are performed by use of each of a plurality of master grooves which have different shapes and are formed in the master grindstone, or the process A and the process B are performed by use of each of portions with different shapes in at least one master groove which is formed in the master grindstone.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to the truing of a high-precision chamfering device at the end face of a plate-shaped workpiece such as a semiconductor wafer or a glass panel made of various materials such as silicon, sapphire, compound, and glass, and more particularly to a truing method for forming a processing groove of a grinding wheel for chamfering and grinding the plate-shaped workpiece, which is a truing for forming a processing groove of a grinding wheel for chamfering and grinding the plate-shaped workpiece.

Background Art

[0002] Conventionally, in order to chamfer and grind a plate-shaped workpiece such as a semiconductor wafer, a grinding wheel is pressed against the outer peripheral portion of the plate-shaped workpiece for processing. Usually, grooves having a shape and dimensions corresponding to the target shape of the plate-shaped workpiece are formed on the outer peripheral portion of the grinding wheel. Then, the grinding of the outer peripheral portion of the plate-shaped workpiece is performed by inserting the outer peripheral portion of the plate-shaped workpiece into the groove and using the inner peripheral surface of the groove. The shape and dimensions of the groove change due to wear or damage of the inner peripheral surface of the groove by repeating the chamfering process, resulting in a decrease in processing accuracy.

[0003] When performing chamfering for a long period of time, it is necessary to replace or re-shape the grinding wheel. Therefore, the grinding wheel is processed using a truing grinding wheel (tru-arc), that is, truing is performed. The truing grinding wheel is produced by grinding while being brought into contact with the inner peripheral surface of the groove of a master grinding wheel having a total shape groove corresponding to the target shape of the plate-shaped workpiece in truing. Then, for the grinding wheel used for actual workpiece chamfering, a total shape groove similar to that of the master grinding wheel is formed by bringing the outer peripheral portion of the truing grinding wheel into contact, and the shape and dimensions are formed. The truing grinding wheel is made of a harder material (for example, GC grinding wheel) than the grinding wheel for chamfering (for example, resin-bonded grinding wheel), and the master grinding wheel is made of a harder material (for example, metal-bonded grinding wheel) than the truing grinding wheel.

[0004] In order to easily true the groove shape of a chamfering grindstone used in a chamfering device for a plate-like object to a desired shape, the groove shape of a master grindstone is transferred to the outer periphery of a truing grindstone, and the outer peripheral shape of this truing grindstone is transferred to the chamfering grindstone to form grooves in the chamfering grindstone, as known, for example, from Patent Document 1.

[0005] Also, in normal grinding, the chamfering portion is ground with the main surface of the wafer perpendicular to the rotation axis of the resin grindstone. In this case, however, circumferential grinding marks are likely to occur in the chamfering portion. Therefore, it is known to perform so-called helical grinding in which, for example, a resin-bonded grindstone is tilted with respect to the wafer to grind the chamfering portion of the wafer.

[0006] When performing helical grinding, if a groove is formed or corrected (trued) using a truer having an axially symmetric shape at the edges with respect to the resin grindstone, since the resin grindstone is tilted, the truer will be twisted, and the grooves of the resin grindstone will be processed into an axially asymmetric shape. Therefore, Patent Document 2 describes that the upper or lower part at the planned position of the groove is processed with a truer having a thickness smaller than the width of the groove of the grindstone for grinding the chamfering portion of the wafer, and then the truer is relatively lowered or raised in the thickness direction with respect to the grindstone for processing to improve the transfer rate and workability of truing and to improve the accuracy of the grooves formed by the truer.

[0007] Also, in order to perform chamfering easily, efficiently, and with high precision, and for the mechanism for supporting and driving the workpiece and the grindstone to be simple, and moreover, to facilitate dressing of the grindstone, the contact portion between the convex grinding portion on the outer peripheral part of the grindstone and the workpiece is moved according to the movement conditions calculated based on the radius of curvature of the arc-shaped portion of the grindstone, and the grindstone is relatively moved with respect to the workpiece, as described in Patent Document 3.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the above prior art, in the method described in Patent Document 1, the turret is directly cut into the groove of the master grindstone, which is a grindstone for turret forming, so that the groove shape is transferred to the edge of the turret. Therefore, for each groove of the master grindstone, only one corresponding shape is possible. Therefore, it is difficult to change the shape of the turret, and it is impossible to cope with changes in the processing conditions of the chamfering device, for example, when the setting of the rotation axis of the grinding wheel changes.

[0010] The methods described in Patent Documents 2 and 3 enable the shape of the turret to be changed, but they are not sufficient for making fine corrections to approach the desired processing shape and for further improving the accuracy of the edge shape of the turret.

[0011] An object of the present invention is to solve the problems of the above prior art, reduce the time and cost required for creating a turret and achieve uniform quality, improve the transfer rate of truing, workability, and the accuracy of the grooves formed in the turret. In particular, the accuracy of the edge shape of the turret is further improved, and not only the dimensional accuracy of the groove shape of the peripheral finishing grindstone, which is the transfer target of the shape, but also the angle of the groove and the corners at the ends are made without roundness, so as to improve the accuracy of the final chamfered shape.

Means for Solving the Problems

[0012] The configuration of the present invention for achieving the above object is as follows.

[0013] [1] A method for forming a turntable in a turning operation of forming a groove of a grinding wheel for grinding a chamfered portion of a wafer by a disk-shaped turntable, the method including: a step A of adjusting the diameter and the rough shape of the turntable by a master grinding wheel for forming the turntable; and a step B of forming an edge of the turntable into a target shape, wherein the step A and the step B are performed using respective ones of a plurality of master grooves having different shapes provided in the master grinding wheel, or the step A and the step B are performed using respective ones of different portions of the shape in at least one master groove provided in the master grinding wheel. [2] The method for forming a turntable according to [1], wherein the step A and the step B are performed using a first groove and a second groove, which are the master grooves having different shapes provided in the master grinding wheel. [3] The method for forming a turntable according to [2], wherein after the turntable is processed by the first groove, an edge processing is performed using a tip of the second groove. [4] The method for forming a turntable according to [2], wherein a radius of an R-shaped portion of the tip of the second groove is larger than a radius of the tip of the first groove. [5] The method for forming a turntable according to any one of [2] to [4], wherein when chamfering the turntable with the master groove, the processing is performed in a direction in which the turntable is pulled. [6] The method for forming a turntable according to [3], wherein a corner R processing for processing a shape, a radius, and a roundness of a corner by reducing a moving distance of the turntable is performed using the tip of the second groove. [7] The method for forming a turntable according to [6], wherein after the corner R processing (upper surface) of the upper surface is completed, the corner R processing (lower surface) of the lower surface is performed. [8] The turret forming method according to [7], wherein the parameters of the movement start point (entry point, entry speed), machining speed, escape position, escape speed, rotational speed of the turret, machining start point, and machining end point are performed with two sets of numerical values for the corner R machining (upper surface) and the corner R machining (lower surface). A turret forming method characterized by this. [9] The turret forming method according to [8], wherein each machining is independently set as a traverse operation with an amplitude, the machining speed, a spark-out time, and the number of reciprocations. A turret forming method characterized by this.

[10] The above step A and the above step B are performed using each of the different-shaped portions in at least one master groove of the master grindstone, and the above step B is performed using the tip of the master groove. The turret forming method according to [1].

[11] The above step A is performed using the bottom of the master groove. The turret forming method according to

[10] .

Advantages of the Invention

[0014] According to the present invention, it is possible to save time and cost and equalize the quality in creating a turret, improve the transfer rate, workability, and accuracy of the grooves formed in the turret of the truing, and in particular, further improve the accuracy of the edge shape of the turret. It is possible to improve the dimensional accuracy of the groove shape of the peripheral finishing grindstone, which is the transfer target of the shape, as well as the angle of the groove and the corners at the ends so that they do not have a rounded shape, and improve the accuracy of the final chamfered shape.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0016] (First Embodiment) Hereinafter, an embodiment (first embodiment) of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing the main part of a wafer chamfering apparatus according to an embodiment of the present invention. The wafer chamfering apparatus 10 includes a wafer feeding unit 20, a grindstone rotating unit 50, a wafer supply / storage unit (not shown), a wafer cleaning / drying unit, a wafer transfer means, and a controller that controls the operations of each part of the wafer chamfering apparatus.

[0017] The wafer feeding unit 20 has an X table 24 that is moved in the X direction in the figure by an X-axis drive mechanism 25 including an X-axis base 21 placed on the main body base 11, two X-axis guide rails 22, four X-axis linear guides 23, a ball screw, and a stepping motor.

[0018] The X table 24 incorporates a Y table 28 that is moved in the Y direction in the figure by a Y-axis drive mechanism including two Y-axis guide rails 26 and four Y-axis linear guides 27, a ball screw (not shown), and a stepping motor.

[0019] The Y table 28 is guided by two Z-axis guide rails 29 and four Z-axis linear guides (not shown), and a Z table 31 that is moved in the Z direction in the figure by a Z-axis drive mechanism 30 composed of a ball screw and a stepping motor is incorporated therein.

[0020] The Z table 31 incorporates a θ-axis motor 32 and a θ spindle 33, and a wafer table 34 for adsorbing and placing a wafer W (a plate-shaped workpiece) is attached to the θ spindle 33. The wafer table 34 is rotated in the θ direction in the figure around the wafer table rotation axis center CW.

[0021] By the wafer feed unit 20, the wafer W and the turret 41 are rotated in the θ direction in the figure and moved in the X, Y, and Z directions.

[0022] The grinding wheel rotation unit 50 has an outer peripheral rough grinding wheel 52 attached thereto, an outer peripheral grinding wheel spindle 51 that is rotationally driven around the axis by an outer peripheral grinding wheel motor (not shown), an outer peripheral finish grinding spindle 54 attached to a turntable 53 disposed above, and an outer peripheral finish grinding motor 56.

[0023] A grinding wheel 55, which is a chamfering grinding wheel for finishing the outer periphery of the wafer W, is attached to the outer peripheral finish grinding spindle 54. The outer peripheral finish grinding spindle 54 performs finish machining of the chamfering of the outer peripheral surface of the wafer W with the rotation axis inclined 3 to 15°, preferably 6 to 10°, with respect to the rotation axis of the wafer W. Thereby, helical grinding is performed, and although weak grinding marks are generated in an oblique direction on the chamfered portion of the wafer W, an effect of improving the surface roughness of the chamfered portion compared to normal grinding is obtained.

[0024] The wafer processing process is carried out in the order of slicing → chamfering → lapping → etching → donor killer → fine chamfering, and various washings are used to remove dirt between processes. Silicon and the like are hard but brittle. If the end face of the wafer remains sharp during slicing, it is likely to crack or chip easily during handling such as conveyance and alignment in subsequent processing steps, and the fragments may damage or contaminate the wafer surface. To prevent this, in the chamfering process, the end face of the cut wafer is chamfered with a chamfering grindstone coated with diamond.

[0025] The grinding wheel 55 is made of, for example, metal powders such as Fe, Cr, Cu, etc. as the main component, mixed with diamond abrasive grains and formed. Its material is preferably made of, for example, phenolic resin, epoxy resin, polyimide resin, polystyrene resin or polyethylene resin as the main component, mixed with diamond abrasive grains or cubic boron nitride abrasive grains and formed.

[0026] Also, the grinding wheel 55 is a resin-bonded grinding wheel with diamond abrasive grains having a diameter of 50 mm, and the grit size #3000 is used. The outer peripheral finishing spindle 54 is a spindle driven by a built-in motor using an air bearing and rotated at a rotational speed of 35000 rpm.

[0027] Figure 2 is a side view showing the truing process. In the grinding wheel 55, the chamfering processing groove is formed by the turret 41. The disk-shaped turret 41 is mounted concentrically with the wafer table rotation axis below the wafer table 34 and rotated by the wafer table 34. The outer peripheral portion of the turret 41 is chamfered on the outer periphery of the turret 41 with a master grindstone (see Figure 3) in advance. That is, in the grinding wheel 55, the chamfering processing groove is formed in the grinding wheel 55 using the turret 41 on which the cross-sectional shape of the master groove (see Figure 3) is transferred to the outer peripheral portion.

[0028] The material of the turntable 41 is preferably formed by binding abrasive grains made of, for example, silicon carbide, adding a filler or the like as necessary, and binding them with a phenolic resin, and molding this into a disc-shaped turntable 41. Further, the turntable 41 has an outer diameter equal to or smaller than that of the wafer W to be processed, and may be a disc-shaped GC (Green silicon carbide) grinding stone or WA (White fused alumina) grinding stone of the same thickness, and the grain size of the grinding stone is preferably about #320.

[0029] Figure 3 shows a side view when the wafer W is processed with a grinding stone 55 having a concave-shaped groove. When the straight portion is processed with a convex grinding stone as described in Patent Document 3, point contact machining is performed, so that uneven wear occurs on the grinding stone, the machining locus remains as streaks, the surface roughness deteriorates, and the machining time becomes long. Further, in the point contact machining with a convex grinding stone, the machining time becomes long and the machining stress escapes, so that it is difficult to form the target shape.

[0030] On the other hand, as shown in Fig. 3(a), when a rough shape is formed with a concave-shaped groove (concave grinding stone), the stresses on the upper inclined surface and the lower inclined surface cancel each other out, reducing the escape of machining stress, and even in the machining of the straight portion, the shape is less likely to become irregular. In addition, in the machining with a concave-shaped groove, since the straight portion also becomes line contact, the machining time is short, no streaks remain, the surface roughness is improved, the machining load is reduced, and the grinding stone life is dramatically improved.

[0031] Fig. 3(b) shows that in the grinding stone 55, machining is performed into an arbitrary finished shape using the tip (arrow A; shown as a straight line in the figure, but may have a curve (surface)) indicated by the arrow A that does not contribute to the machining of the diameter and rough shape. According to this, the shape, radius, roundness, etc. of the corner portion can be machined with higher accuracy. At this time, pulling the wafer W as shown by the arrow B increases the contact area between the wafer W and the grinding stone 55, reducing the machining load and extending the grinding stone life. Further, if the difference between the shape before machining and the target shape is large, the grinding amount at the tip increases and the wear of the grinding stone 55 becomes large, so it is preferable to approximate the groove shape of the grinding stone 55 to the target shape in advance.

[0032] Figure 4(a) is a side view showing a method of forming the screw shaft 41. The master grinding wheel 60 for forming the screw shaft 41 has a plurality of grooves (first groove 61, second groove 62) as master grooves. The first groove 61 is for adjusting the diameter and rough shape of the screw shaft 41 (adjustment of diameter and rough shape). The first groove 61 may be a general groove, and the adjustment of the diameter and rough shape by the first groove 61 may be by transferring the groove shape of the first groove 61 to the screw shaft 41. On the other hand, the second groove 62 is for adjusting the edge of the screw shaft 41 to a target shape (arbitrary and desired cross-sectional shape). The second groove 62 has an R-shaped portion with a larger radius at the tip (opening). That is, the first groove 61 and the second groove 62 have different shapes from each other. By using the R-shaped portion of this second groove, a screw shaft 41 having an arbitrary cross-sectional shape, which cannot be obtained simply by transferring the groove shape, can be obtained.

[0033] Figure 4(b) is an enlarged view of the second groove 62. The second groove 62 has a straight portion 81 substantially parallel to the thickness direction (Z direction) of the master grinding wheel 60, upper and lower inclined portions 82 extending from the end of the straight portion 81, and upper and lower R-shaped portions 83 having curves extending from the ends of the inclined portions 82 to the opening. Note that although the second groove 62 in Figure 4(b) has the straight portion 81, the inclined portion 82, and the R-shaped portion 83, it is not limited to the above, and the second groove 62 may have the straight portion 81 and the R-shaped portion 83. Also, in the figure, the straight portion 81 and the inclined portion 82 are described as straight lines (in cross-sectional shape), but they are not limited to the above and may have curves (may have curved surfaces).

[0034] The master grinding wheel 60 is rotated, for example, at a rotational speed of 8000 rpm. In this state, the Z table 31 is moved by the Z-axis drive mechanism 30, and the height of the screw shaft 41 is positioned at a height that coincides with each groove of the master grinding wheel 60.

[0035] Next, the Y table 28 is moved toward the master grindstone 60. By the movement of the Y table 28 in the Y direction, the outer peripheral portion of the turret 41 is cut into the master groove of the master grindstone 60, and the wafer table 34 slowly rotates once by the θ-axis motor 32. Then, the outer peripheral portion of the turret 41 is chamfered, and the shape of the master groove is transferred to the outer peripheral portion of the turret 41. Next, the turret 41 is moved away from the master grindstone 60, and the transfer from the cross-sectional shape of the master groove to the cross-sectional shape of the outer peripheral portion of the turret 41 is completed.

[0036] The method of transferring from the master groove to the turret 41, that is, the forming process of the turret 41, is as follows: with the first groove 61, the outer peripheral portion of the turret 41 is cut into the first groove 61 as shown by the arrow D above, and the diameter processing and rough shape of the turret 41 are adjusted. Next, edge processing including high-precision adjustment to an arbitrary cross-sectional shape is performed mainly using the R-shaped portion 83 of the second groove 62.

[0037] FIG. 5 is a side view showing the high-precision processing by the second groove 62, FIG. 6 is a flowchart showing the procedure of the forming process of the turret 41, and FIG. 7 is a flowchart showing the detailed procedure of the edge processing (step 4 in FIG. 6). The schematic procedure of the forming method of the turret 41 along FIG. 6 is: (1) input of various conditions (step 1), (2) calculation of processing conditions (processing start point · processing end point) by the chamfering device based on the input various conditions, (3) mainly diameter processing (step 3) as the forming process of the turret 41, and (4) edge processing (step 4).

[0038] (Steps 1, 2) The various conditions to be input are, as parameters, diameter, chamfering angle, tip shape (linear length m of the end face, face width n, size of the corner R), movement start point (entry point, entry speed), chamfering processing speed, corner R processing speed, relief position, relief speed, rotation speed of the turret 41, rotation speed of the master grindstone 60, etc.

[0039] The chamfering method using this chamfering device includes, in addition to the transfer of the shape of the master groove in Step 3 described later, the adjustment to an arbitrary shape using the R-shaped portion of the master groove (second groove) in Step 4. Therefore, as an example of the conditions input in this process, it may be data of an arbitrary and desired cross-sectional shape. The above-mentioned desired cross-sectional shape is preferably smaller than the cross-sectional shape after grinding by the first groove 61 which may be a total shape groove, and can be an arbitrary shape regardless of the groove shapes of the first groove 61 and the second groove 62. Note that the processing conditions calculated by the chamfering device are mainly the processing start point and the processing end point.

[0040] (Step 3: Process A) Step 3 is a process of adjusting the diameter and rough shape of the turret (Process A). This step is performed using the first groove 61. In this step, the master grindstone 60 is rotated at a rotational speed of, for example, 8000 rpm. The processing starts with the height of the turret 41 positioned at the height that coincides with the master groove (first groove 61) of the master grindstone 60. The turret 41 is moved toward the master grindstone 60 as indicated by the arrow D, and the outer peripheral portion of the turret 41 is cut into the master groove (first groove 61) of the master grindstone 60, and mainly the end face of the outer peripheral portion of the turret 41 is chamfered. For the diameter processing, there are two types of processing conditions, namely, corner R processing (upper surface) and corner R processing (lower surface), as parameters. As one form, corner R processing (upper surface) is performed first, and then corner R processing (lower surface) is performed.

[0041] As described above, in this method, since the diameter and rough shape are adjusted using the concave groove, it is difficult for the master grindstone and the turret to be in point contact, and the processing stress is difficult to escape. As a result, grinding can be efficiently performed.

[0042] (Step 4: Specifically, Step 401 to 407: Process B) Step 4 is a process of shaping the edge of the vine arm into the target shape (Process B). The processing in this step is performed using a second groove 62 having a (cross-sectional) shape different from that of the first groove 61. The "second groove 62 having a shape different from that of the first groove 61" means, as one form, that the second groove 62 has an R-shaped portion at the tip (the portion near the opening), and any other form may be used as long as the shape is different from the portion used in Process A. Returning to the flow, specifically, first, after the diameter and rough shape are processed by the first groove 61, the vine arm 41 is moved to the starting point of movement that coincides with the height of the second groove 62 shown in Fig. 5(a) (Step 401).

[0043] The chamfering device sets the parameters of the processing conditions based on the various conditions (data such as the desired cross-sectional shape) input previously (Step 402). Next, the vine arm 41 moves to the entry point at a predetermined entry speed (Step 403). The vine arm 41 starts rotating (Step 404) and chamfers the portion shown by the thick line in Fig. 5(b) at a predetermined chamfering angle (Step 405). At this time, since the second groove 62 is a concave groove, the processing is a line contact processing, so the processing time is short, no streak remains, the surface roughness is improved, and the processing load is reduced. Also, it is desirable to perform the chamfering process in the direction of pulling the vine arm 41 as shown by the arrow B in Fig. 5(c) to reduce the processing load.

[0044] After the chamfering process, the movement distance of the vine arm 41 (i.e., the machining feed amount) is reduced, and a corner R process is performed to machine more detailed parts, specifically, the shape, radius, roundness, etc. of the corner (Step 406). The corner R process (upper surface) is performed using the tip with the R-shaped portion shown by the arrow A that does not contribute to the diameter processing of the second groove 62. The tip of the second groove 62 has a larger radius of the R-shaped portion compared to the tip of the first groove 61. Therefore, the machining of the shape, radius, roundness, etc. of the corner of the vine arm 41 is more accurate, no streak remains, and the surface roughness is improved.

[0045] After the corner R machining (upper surface) is completed, since the corner R machining (lower surface) is to be performed, move to the corresponding movement start point in step 401, and repeat steps 401 to 405 in the same manner. Also, parameters such as the movement start point (entry point, entry speed), relief position, machining speed, relief speed, rotation speed of the turret 41, machining start point, and machining end point are set with two sets of numerical values for the corner R machining (upper surface) and the corner R machining (lower surface).

[0046] For each machining, in order to improve the surface roughness, it is preferable to independently set the amplitude, machining speed, spark-out time, and number of reciprocations as traverse operations. Note that spark-out means continuing grinding without giving a cut at the end of the grinding operation, and the machining progresses in small amounts.

[0047] Note that when the truing fails to satisfy the predetermined outer peripheral surface width, outer peripheral angle, and outer peripheral shape due to a decrease in the grinding ability, the groove correction (truing) of the grinding wheel 55 is appropriately performed using the turret 41. At this time, if truing is performed according to the present invention, the number of wafers that can be processed per truing increases, and even for a resin grinding wheel, the life is extended and the number of wafers that can be processed with one resin grinding wheel increases. Therefore, it also leads to a reduction in the cost in the manufacture of semiconductor wafers.

[0048] According to the present embodiment, even when the grinding wheel 55 is changed to another shape, it is not necessary to use another turret forming grinding wheel (groove). Therefore, the present embodiment can not only improve the accuracy of the grinding wheel 55, but also eliminate the need for the work of replacing the grinding wheel and the new production of the grinding wheel. Compared with the case of newly producing the grinding wheel, in addition to cost savings, the period from ordering the grinding wheel from the grinding wheel manufacturer to receiving the grinding wheel can be shortened.

[0049] (Second Embodiment) Next, a second embodiment will be described in which the second groove 62 is used to perform processing of a diameter and a rough shape, and adjustment to an arbitrary shape (edge processing). Note that since the wafer chamfering device and the like used are the same as those in the first embodiment, the description thereof will be omitted. Hereinafter, the description will focus on the parts different from the first embodiment.

[0050] FIG. 8 is an explanatory diagram showing the procedure of the forming process of the turret 41 in the present embodiment performed using the second groove 62. First, FIG. 8(a) shows the state of the turret 41 before processing. In the following steps, first, the diameter and rough shape of this turret 41 are adjusted to have a cross-sectional shape 84.

[0051] Note that the drawings are schematic, and the shapes are exaggerated to clearly explain the difference in the shape of the turret 41 before and after processing. Also, in FIG. 8, the processing target (grinding target) is the turret 41, but this method is not limited to the turret 41 and is also applicable to grinding of wafers and the like.

[0052] FIG. 8(b) shows the state of cutting into the master grindstone 60 that rotates the turret in order to adjust the diameter and rough shape of the turret 41 to have a cross-sectional shape 84 (step A). At this time, the end portion of the turret 41 comes into contact with the straight portion 81 and the inclined surface portion 82, which are the bottom portions of the second groove 62 of the master grindstone, and is ground. In other words, in the present embodiment, step A is performed using the straight portion 81 and the inclined surface portion 82, which are the bottom portions of the second groove. The straight portion 81 and the inclined surface portion 82 have the same function as the concave groove such as the first groove 61 described above, and can mainly adjust the diameter and rough shape of the turret 41 in a line contact state while preventing stress from escaping.

[0053] After finishing the adjustment of the rough shape and reaching the state where the cross-sectional shape is 84, for the turret 41, next, edge processing is performed by the R-shaped portion 83 (step B). This step B is carried out in the second groove 62 using a portion different from that used in the processing of step A and having a different shape. Specifically, it is carried out using the R-shaped portion 83 at the tip of the second groove 62 (the tip in the opening direction).

[0054] As already described, the straight portion 81 and the inclined surface portion 82 used in step A have the function as a concave groove, and are in line contact with the turret 41 to more efficiently adjust the rough shape without releasing stress. In other words, the groove shape can be easily transferred to the turret 41.

[0055] On the other hand, the R-shaped portion 83 used in step B is convex toward the inside of the groove as compared with the straight portion 81 and the inclined surface portion 82 being linearly configured, and has a different shape. Here, when the turret 41 is brought into contact, it can be processed into an arbitrary shape according to the position and the way of contact.

[0056] Returning to the description of the process, when the adjustment of the diameter and the rough shape is completed, the turret 41 moves in the Z(-) direction while moving away from the straight portion 81 and the inclined surface portion 82 (in order to change the position to be used) along the R-shaped portion 83 in the Z(-) direction of the second groove 62. The arrow in Fig. 8(b) represents the moving direction of the turret 41.

[0057] While moving along the R-shaped portion 83, edge processing of the turret 41 is performed. Figs. 8(c)(d) show the state of the edge processing by the R-shaped portion 83. In this step, based on the data of the desired cross-sectional shape received in step 1 of Fig. 6 already described, while moving the turret 41 along the R-shaped portion 83 (reciprocating as necessary), the edge shape and the like are adjusted. Typically, it is preferable that the R-shaped portion 83 is not in contact with the turret 41 during the adjustment of the diameter and rough shape (process A). Since the R-shaped portion 83 has a curved surface shape, its cross-sectional shape can be easily adjusted arbitrarily depending on the way of applying the turret 41, that is, the way of moving the turret 41 in the Y and Z axis directions (process B).

[0058] Next, in the same manner, as shown in FIGS. 8(e) and 8(f), while moving the turret 41 along the R-shaped portion 83 on the upper side (Z(+)) of the second groove 62, the shape of the (mainly) upper end side of the turret 41 is adjusted. In the present embodiment, the lower side of the turret 41 is processed first. However, as already described, the upper side of the turret 41 may be processed first.

[0059] FIG. 8(g) shows the turret 41 after the edge processing is completed. The adjusted cross-sectional shape 85 of the turret 41 adjusted in this way may have a different shape from 84 after the diameter and rough shape are adjusted by the straight portion 81 and the inclined surface portion 82. In other words, according to this method, using the second groove 62, the diameter and rough shape can be adjusted, and further, it can be processed so as to have an arbitrary cross-sectional shape.

[0060] Conventionally, in the forming of a turret using a master grindstone, due to the convenience of transferring the shape of the master groove to the turret, the shape of each master groove corresponded to the cross-sectional shape of each turret. Therefore, when attempting to adjust a plurality of turrets to different cross-sectional shapes, methods such as preparing and replacing a plurality of master grindstones to transfer the shape, or using a master grindstone having a plurality of master grooves to transfer the shape of different master grooves have been adopted.

[0061] However, according to this method, without using a master grindstone or a plurality of master grooves, the cross-sectional shape of the turret can be arbitrarily adjusted using a master groove having an R-shaped portion at the opening.

Explanation of Reference Numerals

[0062] 10... Wafer chamfering device 11… Body base 20… Wafer feed unit 21… X-axis base 22… X-axis guide rail 23… X-axis linear guide 24… X-table 25… X-axis drive mechanism 26… Y-axis guide rail 27… Y-axis linear guide 28… Y-table 29… Z-axis guide rail 30… Z-axis drive mechanism 31… Z-table 32… θ-axis motor 33… θ-spindle 34… Wafer table 41… Turret 50… Grinding wheel rotation unit 51… Outer peripheral grinding wheel spindle 52… Outer peripheral rough grinding wheel 53… Turntable 54… Outer peripheral fine grinding spindle 55… Grinding wheel 56… Outer peripheral fine grinding motor 60… Master grinding wheel 61… First groove 62… Second groove 81… Straight part 82… Inclined surface part 83… R-shaped part 84… Cross-sectional shape 85… Cross-sectional shape CW… Axis of rotation of wafer table GC… Disk-shaped W… Wafer n… Face width

Claims

1. A turret forming method in truing for forming a groove of a grinding wheel for grinding a chamfered portion of a wafer by a disk-shaped turret, comprising: Step A of adjusting the diameter and rough shape of the turret by a master grinding wheel for forming the turret; Step B of forming the edge of the turret into a target shape; and The master grinding wheel includes a first groove and a second groove, which are master grooves having different shapes. In the turret forming method, Step A is performed using one of the first groove and the second groove, and Step B is performed using the other of the first groove and the second groove.

2. The turret forming method according to claim 1, wherein an edge processing is performed using the tip of the second groove after the turret is processed by the first groove.

3. The turret forming method according to claim 1, wherein the radius of the R-shaped portion of the tip of the second groove is larger than that of the tip of the first groove.

4. The turret forming method according to any one of claims 1 to 3, wherein when chamfering the turret with the master groove, the processing is performed in the direction of pulling the turret.

5. The turret forming method according to claim 1, wherein a corner R process for processing the shape, radius, and roundness of a corner by making the moving distance of the turret smaller than that during chamfering is performed using the tip of the second groove.

6. The turret forming method according to claim 5, wherein the corner R process (bottom surface) of the bottom surface is performed after the corner R process (top surface) of the top surface is completed.

7. The method for forming a turret according to claim 6, wherein parameters regarding processing conditions are independently set for the corner R processing (upper surface) and the corner R processing (lower surface), respectively.

8. The method for forming a turret according to claim 7, wherein the processing in the step A and the step B is independently set as a traverse operation with an amplitude, a processing speed, a spark-out time, and a number of reciprocations.

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