JP2024001517A - Truer molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to the truing of various materials such as silicon, sapphire, compounds, glass, etc., with a high-precision chamfering device on the end face of plate-shaped workpieces, especially semiconductor wafers, glass panels, etc. The present invention relates to a truer forming method in truing for forming processing grooves on a grindstone.

Conventionally, in order to chamfer and grind a plate-shaped workpiece such as a semiconductor wafer, a grindstone is pressed against the outer periphery of the plate-shaped workpiece. Usually, a groove having a shape and size corresponding to the target shape of the plate-shaped workpiece is formed on the outer circumference of the grindstone. 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 on the inner peripheral surface of the groove due to repeated chamfering, resulting in a decrease in processing accuracy.

When chamfering is performed over a long period of time, the grindstone needs to be replaced or reshaped. Therefore, the grindstone is processed using a truing grindstone (truer), that is, truing is performed. A truing grindstone is produced by grinding a plate-shaped workpiece by bringing it into contact with the inner circumferential surface of a groove of a master grindstone, which has a general groove corresponding to the target shape of a plate-shaped workpiece during truing. The grindstone used for chamfering an actual workpiece is brought into contact with the outer circumferential portion of the truing grindstone to form a general groove similar to that of the master grindstone, and to shape the shape and dimensions. The truing whetstone is made of a harder material (for example, a GC whetstone) than a chamfering whetstone (for example, a resin bond whetstone), and the master whetstone is made of a harder material (for example, a metal bond whetstone) than the truing whetstone.

In order to easily truing the groove shape of a chamfering whetstone used in a device for chamfering plate-shaped objects into a desired shape, the groove shape of the master whetstone is transferred to the outer periphery of the truing whetstone, and the outer circumferential shape of this truing whetstone is It is known to form grooves on a chamfering grindstone by transferring it to the chamfering grindstone, and is described in, for example, Patent Document 1.

In addition, in normal grinding, the chamfer is ground with the main surface of the wafer perpendicular to the rotation axis of the resin grindstone, but in this case, circumferential grinding marks are likely to occur on the chamfer. Therefore, it is known to perform so-called helical grinding, in which the chamfered portion of the wafer is ground by tilting a resin bond grindstone relative to the wafer.

When performing helical grinding, if grooves are formed or corrected (truing) using a truer whose edges are vertically symmetrical on a resin grinding wheel, the truer becomes twisted because the resin grinding wheel is inclined. As a result, the grooves of the resin grindstone are machined into a vertically asymmetrical shape. Therefore, the upper or lower part of the groove is processed at the intended position using a truer whose thickness is smaller than the width of the groove of the grinding wheel used to grind the chamfered part of the wafer, and then the truer is moved in the thickness direction relative to the grinding wheel. Patent Document 2 describes that machining is performed by lowering or raising the truing to improve the transfer rate and workability of truing, and to improve the accuracy of the groove formed by the truer.

In addition, in order to easily and efficiently perform chamfering with high precision, the mechanism for supporting and driving the workpiece and grinding wheel is simple, and the grinding wheel is easily shaped, the convex grinding part on the outer periphery of the grinding wheel and the workpiece are Patent Document 3 describes that a grindstone is moved relative to a workpiece according to a movement condition in which a contact portion with a workpiece is calculated based on a radius of curvature of an arc-shaped portion of the grindstone.

Japanese Patent Application Publication No. 2005-153085 Japanese Patent Application Publication No. 2018-167331 Japanese Patent Application Publication No. 2021-181151

In the above-mentioned conventional technology, the method described in Patent Document 1 cuts the truer directly into the groove of the master whetstone, which is a whetstone for forming the truer, and transfers the groove shape to the edge of the truer, so that the groove shape of the master whetstone is transferred to the edge of the truer. Only one type of shape can be supported. Therefore, it is difficult to change the shape of the truer, and it is not possible to respond to changes in the machining conditions of the chamfering device, for example, the setting of the rotation axis of the grinding wheel.

The methods described in Patent Documents 2 and 3 make it possible to change the shape of the truer, but it is necessary to perform minute corrections to bring it closer to the desired processed shape, and to further improve the accuracy of the edge shape of the truer. It wasn't enough.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, to reduce the time and cost required for creating trueing, to make the quality uniform, and to improve the transfer rate of trueing, workability, and the accuracy of grooves formed on trueing. In particular, we have further improved the accuracy of the edge shape of the Truer, and have not only improved the dimensional accuracy of the groove shape of the outer peripheral fine grinding wheel to which the shape is transferred, but also improved the roundness of the groove angle and edge corners. The purpose is to improve the accuracy of the final chamfered shape by preventing chamfering.

The configuration of the present invention to achieve the above object is as follows.

[1] A trueer forming method in truing in which a groove on a grindstone for grinding a chamfered portion of a wafer is formed by a disc-shaped truer, the diameter and rough shape of the trueer being adjusted by a master grindstone for shaping the trueer. It includes a step A and a step B of forming the edge of the truer into a target shape, and the step A and the step B use each of a plurality of master grooves having different shapes of the master grindstone. or the above-mentioned step A and the above-mentioned step B are performed using each of different shaped portions of at least one master groove of the master grindstone.
[2] The method according to [1], wherein the step A and the step B are performed using the first groove and the second groove, which are the master grooves of different shapes, which the master grindstone has. Truer molding method.
[3] The true forming method according to [2], wherein after the true is processed in the first groove, edge processing is performed using the tip of the second groove. Method.
[4] The truer forming method according to [2], wherein the tip of the second groove has a larger radius of the rounded portion than the tip of the first groove. .
[5] The truer forming method according to any one of [2] to [4], characterized in that when chamfering the truer in the master groove, processing is performed in the direction in which the truer is pulled. True molding method.
[6] The truer forming method according to [3], wherein the corner R processing for processing the shape, radius, and roundness of the corner by reducing the moving distance of the truer is performed using the tip of the second groove. A truer molding method characterized by:
[7] The truer forming method according to [6], wherein the corner R processing of the lower surface (lower surface) is performed after the corner R processing of the upper surface (upper surface) is completed.
[8] The truer forming method according to [7], wherein the movement start point (approach point, approach speed), machining speed, escape position, escape speed, rotational speed of the truer, machining start point, machining end point. A truer forming method characterized in that the parameters are two values for the corner R processing (upper surface) and the corner R processing (lower surface).
[9] The true forming method according to [8], wherein the amplitude, the processing speed, the spark-out time, and the number of reciprocations are set independently for each process as a traverse operation. Method.
[10] The above-mentioned process A and the above-mentioned process B are performed using each of different shaped portions of at least one master groove of the master whetstone, and the above-mentioned process B is performed by using the tip portion of the master groove. The truer molding method according to [1], which is performed using the truer molding method.
[11] The true molding method according to [10], wherein the step A is performed using the bottom of the master groove.

According to the present invention, it is possible to reduce the time and cost required for creating a true ring and to make the quality uniform, and the transfer rate of the true ring, workability, and accuracy of the grooves formed on the true ring are improved, and in particular, the edge of the true ring is improved. The accuracy of the shape has been further improved, and not only the dimensional accuracy of the groove shape of the outer peripheral fine grinding wheel to which the shape is transferred, but also the angle of the groove and the corners of the edges are prevented from being rounded. The accuracy of chamfered shapes can be improved.

FIG. 1 is a front view showing main parts of a chamfering device according to an embodiment of the present invention. It is a side view showing truing processing in one embodiment. FIG. 3 is a side view when processing a wafer W with a grinding wheel 55 having a concave groove in one embodiment. FIG. 4 is a side view showing a method of molding truer 41 in one embodiment. FIG. 7 is a side view showing high-precision machining with the second groove 62 in one embodiment. It is a flowchart which shows the procedure of the molding process of the truer 41 by one embodiment. 7 is a flowchart illustrating a procedure for edge processing in FIG. 6 according to an embodiment. It is an explanatory view showing a procedure of molding processing of truer 41 in one embodiment (2nd embodiment) of the present invention.

(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 parts 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 rotation unit 50, a wafer supply/storage section (not shown), a wafer cleaning/drying section, a wafer transport means, a controller that controls the operation of each part of the wafer chamfering apparatus, and the like. There is.

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

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 consisting of two Y axis guide rails 26, four Y axis linear guides 27, and a ball screw (not shown) and a stepping motor. It is.

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

The Z table 31 incorporates a θ-axis motor 32 and a θ spindle 33, and a wafer table 34 on which a wafer W (a plate-shaped workpiece) is placed by suction 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 CW.

The wafer W and truer 41 are rotated in the θ direction in the figure and moved in the X, Y, and Z directions by the wafer feeding unit 20.

The grindstone rotation unit 50 includes an outer circumferential rough grinding wheel 52 attached thereto, an outer circumferential grindstone spindle 51 that is rotationally driven around the axis by an outer circumferential grindstone motor (not shown), and an outer circumferential fine grinder attached to a turntable 53 disposed above. It has a spindle 54 and a peripheral fine polishing motor 56.

A grinding wheel 55, which is a chamfering wheel for finishing grinding the outer periphery of the wafer W, is attached to the outer periphery polishing spindle 54. The outer periphery polishing spindle 54 performs finishing processing for chamfering the outer periphery of the wafer W with its rotation axis inclined at 3 to 15 degrees, preferably 6 to 10 degrees with respect to the rotation axis of the wafer W. As a result, helical grinding is performed, and although weak grinding marks are generated in the diagonal direction on the chamfered portion of the wafer W, the effect of improving the surface roughness of the chamfered portion compared to normal grinding can be obtained.

The wafer processing process is performed in the order of slicing → chamfering → lapping → etching → donor killer → fine chamfering, and various cleaning methods are used between steps to remove dirt. Silicon and other materials are hard and brittle, and if the edges of the wafer remain sharp during slicing, they will easily break or chip during handling during transportation and alignment in subsequent processing steps, and the fragments may damage or contaminate the wafer surface. or To prevent this, in the chamfering process, the end face of the cut wafer is chamfered using a diamond-coated chamfering grindstone.

The grinding wheel 55 is made of, for example, metal powder such as Fe, Cr, or Cu as a main component, and is formed by mixing diamond abrasive grains. Preferably, the material is made of, for example, phenol resin, epoxy resin, polyimide resin, polystyrene resin, or polyethylene resin as a main component, mixed with diamond abrasive grains or cubic boron nitride abrasive grains.

The grinding wheel 55 is a resin bonded diamond abrasive wheel with a diameter of 50 mm and a grain size of #3000. The outer circumferential polishing spindle 54 is a spindle driven by a built-in motor using an air bearing, and is rotated at a rotational speed of 35,000 rpm.

FIG. 2 is a side view showing the truing process, in which the grinding wheel 55 has a chamfering groove formed by the truer 41. The disk-shaped truer 41 is attached to the lower part of the wafer table 34 so as to be concentric with the wafer table rotation axis, and is rotated by the wafer table 34 . The outer periphery of the truer 41 is chamfered in advance using a master grindstone (see FIG. 3). In other words, a chamfering groove is formed on the grinding wheel 55 using the truer 41 on which the cross-sectional shape of the master groove (see FIG. 3) is transferred to the outer peripheral portion.

The material of the truer 41 is preferably one in which abrasive grains made of silicon carbide, for example, are bonded with a phenol resin with addition of a filler if necessary, and this is formed into the disk-shaped truer 41. Further, the truer 41 may be a disc-shaped GC (Green silicon carbide) grinding wheel or a WA (White fused alumina) grinding wheel, which has an outer diameter equal to or smaller than that of the wafer W to be processed and has the same thickness, and the grain size of the grinding wheel is #320. Good condition.

FIG. 3 shows a side view when processing the wafer W with the grinding wheel 55 having concave grooves. If straight sections are machined using a convex grindstone as described in Patent Document 3, the process will be performed by point contact, which may cause uneven wear on the grindstone, leave machining traces as marks, and cause surface roughness. This may result in poor quality or longer machining time. In addition, point contact machining using a convex grindstone increases machining time and releases machining stress, making it difficult to form the target shape.

On the other hand, as shown in Fig. 3(a), if a rough shape is formed using a concave groove (concave grindstone), the stress between the upper and lower slopes is canceled out, reducing the escape of machining stress, and machining straight sections. Even so, the shape is less likely to become irregular.
In addition, when machining concave grooves, straight sections are also in line contact, so machining time is short, no streaks are left, surface roughness is improved, machining load is reduced, and grinding wheel life is dramatically improved. do.

FIG. 3(b) shows the tip of the grinding wheel 55 indicated by arrow A that does not contribute to machining the diameter and rough shape (arrow A; although it is shown as a straight line in the figure, it has a curved line (surface). This indicates that it can be processed into an arbitrary finished shape using the following methods. According to this, the shape, radius, roundness, etc. of the corner can be processed with higher precision. At this time, pulling the wafer W as shown by arrow B increases the contact area between the wafer W and the grinding wheel 55, reducing the processing load and extending the life of the grinding wheel. Further, if the difference between the shape before machining and the target shape is large, the amount of grinding at the tip will increase and the wear of the grinding wheel 55 will increase, so it is preferable to make the groove shape of the grinding wheel 55 close to the target shape in advance.

FIG. 4(a) is a side view showing a method of molding the truer 41. The master grindstone 60 for forming the truer 41 has a plurality of grooves (a first groove 61 and a second groove 62) as master grooves. The first groove 61 is for adjusting the diameter and rough shape of the truer 41 (diameter and rough shape adjustment). The first groove 61 may be a full-shaped groove, and the adjustment of the diameter and rough shape by the first groove 61 may be performed by transferring the groove shape of the first groove 61 to the truer 41.
On the other hand, the second groove 62 is for adjusting the edge of the truer 41 to a target shape (an 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. By using the rounded portion of the second groove, a truer 41 having an arbitrary cross-sectional shape that cannot be obtained by simply transferring the groove shape can be obtained.

FIG. 4(b) is an enlarged view of the second groove 62. The second groove 62 includes a linear portion 81 substantially parallel to the thickness direction (Z direction) of the master whetstone 60, an upper and lower sloped portion 82 extending from the end of the linear portion 81, and an opening from the end of the sloped portion 82. It has upper and lower R-shaped portions 83 having curved lines extending to the upper and lower sides.
Although the second groove 62 in FIG. 4(b) has a straight portion 81, a sloped portion 82, and an R-shaped portion 83, the second groove 62 is not limited to the above. 81 and the rounded portion 83.
In addition, although the straight portion 81 and the slope portion 82 are shown as straight lines (in cross-sectional shape) in the figure, they are not limited to the above, and may have curves (have curved surfaces). good).

The master grindstone 60 is rotated at a rotation speed of 8000 rpm, for example. In this state, the Z table 31 is moved by the Z-axis drive mechanism 30 and positioned at a height where the height of the truer 41 matches the respective grooves of the master grindstone 60.

Next, the Y table 28 is moved toward the master grindstone 60. By moving the Y table 28 in the Y direction, the outer circumference of the truer 41 is cut into the master groove of the master grindstone 60, and the wafer table 34 is slowly rotated once by the θ-axis motor 32. Then, the outer peripheral portion of the truer 41 is chamfered, and the shape of the master groove is transferred to the outer peripheral portion of the truer 41. Next, the truer 41 is moved in a direction 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 truer 41 is completed.

The method of transferring from the master groove to the truer 41, that is, the molding process of the truer 41, is to cut the outer periphery of the truer 41 into the first groove 61 as described above in the direction of arrow D, and adjust the diameter of the truer 41. Processing and rough shaping. Next, using mainly the rounded portion 83 of the second groove 62, edge processing is performed with high precision, including adjustment to an arbitrary cross-sectional shape.

FIG. 5 is a side view showing a high-precision processing process using the second groove 62, FIG. 6 is a flowchart showing a procedure for forming the truer 41, and FIG. 7 is an edge processing process in FIG. 6 (Step 4 in FIG. 6). ) is a flowchart showing detailed steps.
The general procedure for forming the truer 41 according to FIG. ) calculation, (3) forming processing of the truer 41 mainly includes diameter processing (step 3), and (4) edge processing (step 4).

(Steps 1 and 2)
The input conditions include the diameter, chamfering angle, tip shape (linear length m of the end face, surface width n, size of corner radius), movement start point (approach point, approach speed), chamfering speed, These include the machining speed of the corner R, the relief position, the relief speed, the rotation speed of the truer 41, the rotation speed of the master grindstone 60, etc.

The chamfering method using this chamfering device includes, in addition to transferring the shape of the master groove in step 3 described later, adjusting the master groove (second groove) to an arbitrary shape using the rounded part in step 4. .
Therefore, as an example of the conditions input in this step, data on an arbitrary and desired cross-sectional shape may be used.
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 full-shaped groove, and can be arbitrarily selected regardless of the groove shapes of the first groove 61 and the second groove 62. It can be in the shape of
Note that the machining conditions calculated by the chamfering device are mainly a machining start point and a machining end point.

(Step 3: Process A)
Step 3 is a step of adjusting the diameter and rough shape of the truer (step A). This step is performed using the first groove 61. In this step, the master grindstone 60 is rotated at a rotation speed of 8000 rpm, for example. Machining is started when the height of the truer 41 is positioned at a height that matches the master groove (first groove 61) of the master grindstone 60. The truer 41 is moved toward the master whetstone 60 as shown by arrow D, and the outer circumference of the truer 41 is cut into the master groove (first groove 61) of the master whetstone 60, mainly cutting the outer circumference of the truer 41 into the master groove (first groove 61). The end face is chamfered. Diameter machining processing has two machining conditions as parameters: corner R machining (top surface) and corner R machining (bottom surface). One form is to perform corner R machining (top surface) first, then corner R machining ( (bottom side).

As mentioned above, in this method, the diameter and rough shape are adjusted using concave grooves, so it is difficult for the master grindstone and the truer to make point contact, making it difficult for machining stress to escape, and as a result, grinding can be performed efficiently. .

(Step 4: In detail, Steps 401 to 407: Process B)
Step 4 is a step of shaping the edge of the truer into a target shape (step B). The processing in this step is performed using the second groove 62 having a different (cross-sectional) shape from the first groove 61. "The second groove 62 having a shape different from the first groove 61" means that, as one form, the second groove 62 has an R-shaped part at the tip (portion near the opening), As long as the shape is different from the part used in step A, a form other than the above may be used.
Returning to the flow, specifically, first, after the diameter and rough shape are machined in the first groove 61, the truer 41 is moved to the movement start point that corresponds to the height of the second groove 62 shown in FIG. 5(a). This is done by moving (step 401).

The chamfering device sets parameters for processing conditions based on the previously input conditions (data such as desired cross-sectional shape) (step 402). Next, the truer 41 moves to the entry point at a predetermined entry speed (step 403). The truer 41 starts rotating (step 404), and chamfers the portion indicated 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 machining is performed by line contact, so the machining time is short, no streaks remain, the surface roughness is improved, and the machining load is reduced. Further, it is preferable that the chamfering process be performed in the direction in which the truer 41 is pulled as shown by arrow B in FIG. 5(c) to reduce the processing load.

After the chamfering process, the moving distance of the truer 41 (that is, the machining feed amount) is reduced to perform corner R machining to process more details, specifically, the shape, radius, roundness, etc. of the corner. (Step 406). Corner radius processing (upper surface) is performed using the tip with an R-shaped portion shown by arrow A that does not contribute to diameter processing of the second groove 62. The radius of the rounded portion at the tip of the second groove 62 is larger than that at the tip of the first groove 61. Therefore, the shape, radius, roundness, etc. of the corners of the truer 41 can be processed with better precision, and no streaks remain, resulting in improved surface roughness.

Note that after corner R machining (top surface) is completed, corner R machining (bottom surface) is performed, so in step 401 the robot moves to the corresponding movement start point, and steps 401 to 405 are repeated in the same manner. In addition, parameters such as the movement start point (approach point, approach speed), escape position, machining speed, escape speed, rotation speed of the truer 41, machining start point, machining end point, corner R machining (top surface) and corner R machining This is done by taking two numbers: (lower surface).

For each machining, it is preferable to independently set the amplitude, machining speed, spark-out time, and number of reciprocations as a traverse operation in order to improve the surface roughness. Incidentally, spark-out refers to an operation in which grinding is continued without making a cut at the end of the grinding operation, and the machining progresses in small increments.

Note that in truing, when the predetermined outer circumferential width, outer circumferential angle, and outer circumferential shape are no longer satisfied due to a decrease in the grinding ability, the groove of the grinding wheel 55 is appropriately corrected (truing) using the truer 41. At this time, if truing is performed according to the present invention, the number of wafers that can be processed per truing will increase, and even if the resin grinding wheel is used, the lifespan will be extended and the number of wafers that can be processed with one resin grinding wheel will increase. . Therefore, it also leads to a reduction in costs in manufacturing semiconductor wafers.

According to this embodiment, even when changing the shape of the grinding wheel 55 to another type, there is no need to use another grindstone (groove) for truer forming. Therefore, the present embodiment not only improves the accuracy of the grinding wheel 55, but also eliminates the need to replace the grinding wheel or create a new one, and in addition to reducing the cost compared to the case where a new grinding wheel is manufactured. , the period from placing an order to a whetstone manufacturer to delivery of the whetstone can be shortened.

(Second embodiment)
Hereinafter, a second embodiment will be described in which the second groove 62 is used to process the diameter and rough shape, and adjust it to an arbitrary shape (edge processing). Note that the wafer chamfering apparatus and the like used are the same as those in the first embodiment, and therefore the description thereof will be omitted. Below, the explanation will focus on parts that are different from the first embodiment.

FIG. 8 is an explanatory diagram showing the procedure of the molding process of the truer 41 in this embodiment, which is performed using the second groove 62.
First, FIG. 8(a) shows the state of the truer 41 before processing. In the following steps, first, the diameter and rough shape of this truer 41 are adjusted so that it has a cross-sectional shape 84.

Note that the drawings are schematic, and the shapes are exaggerated in order to clearly explain the difference in shape of the truer 41 before and after processing.
Further, in FIG. 8, the processing target (grinding target) is the truer 41, but the present method is applicable not only to the truer 41 but also to grinding of wafers and the like.

FIG. 8B shows how the truer is cut into the rotating master grindstone 60 in order to adjust the diameter and rough shape of the truer 41 to have the cross-sectional shape 84 (step A). At this time, the end of the truer 41 contacts the straight portion 81 and the sloped portion 82, which are the bottoms of the second grooves 62 of the master grindstone, and is ground. In other words, in this embodiment, step A is performed using the straight portion 81 and the sloped portion 82, which are the bottoms of the second grooves.
The straight portion 81 and the slope portion 82 have the same function as the concave grooves such as the first groove 61 described above, and are mainly in line contact with the truer 41 while preventing stress from escaping. The diameter and rough shape can be adjusted.

After completing the rough shape adjustment, the truer 41 whose cross-sectional shape is 84 is then subjected to edge processing using the rounded portion 83 (step B). This step B is carried out using a portion of the second groove 62 that is different from that used in the processing of step A and has a different shape. Specifically, this is carried out using the rounded portion 83 at the tip of the second groove 62 (the tip in the opening direction).

As already explained, the straight portion 81 and the sloped portion 82 used in step A have the function of a concave groove, and are in line contact with the truer 41 to more efficiently shape the rough shape without releasing stress. It can be arranged. In other words, the groove shape can be easily transferred to the truer 41.

On the other hand, the rounded portion 83 used in step B has a convex shape toward the inside of the groove, compared to the linear portion 81 and the sloped portion 82, which are configured in a straight line. Different shapes. When the truer 41 is brought into contact with this, it can be processed into any shape depending on the position and the manner of contact.

Returning to the description of the process, once the adjustment of the diameter and rough shape is completed, the truer 41 is aligned with the R-shaped part 83 of the second groove 62 in the Z (-) direction, and the straight part 81 and the slope part 82 are aligned. Move in the Z (-) direction while moving away from (to change the position of use). The arrow in FIG. 8(b) represents the moving direction of the truer 41.

Edge processing of the truer 41 is performed while moving along the rounded portion 83. FIGS. 8(c) and 8(d) show how edge processing is performed by the rounded portion 83. In this step, based on the desired cross-sectional shape data received in step 1 of FIG. be adjusted.
Typically, it is preferable that the rounded portion 83 not be in contact with the truer 41 during diameter/rough shape adjustment (step A). Since the R-shaped portion 83 has a curved surface shape, its cross-sectional shape can be easily adjusted as desired by the way the truer 41 is applied, that is, the way the truer 41 is moved in the Y and Z axis directions. ).

Next, in the same manner, as shown in FIGS. 8(e) and 8(f), while moving the truer 41 along the R-shaped portion 83 on the upper side (Z(+)) side of the second groove 62, , adjust the shape (mainly) of the upper end side of the truer 41.
In this embodiment, the lower side of the truer 41 is processed first, but as already explained, the upper side of the truer 41 may be processed first.

FIG. 8(g) shows the truer 41 after the edge processing is completed. The adjusted cross-sectional shape 85 of the truer 41 adjusted in this manner may be different from the cross-sectional shape 84 after the diameter and rough shape have been adjusted by the straight portion 81 and the sloped portion 82. In other words, according to this method, the diameter and rough shape can be adjusted using the second groove 62, and further, it can be processed to have an arbitrary cross-sectional shape.

Conventionally, in forming a truer using a master grindstone, the shape of each master groove corresponds to the cross-sectional shape of each trueer in order to transfer the shape of the master groove to the truer. Therefore, when trying to adjust multiple truers to different cross-sectional shapes, it is necessary to prepare multiple master whetstones and exchange them to transfer the shape, or to use a master whetstone with multiple master grooves and use a separate master whetstone for each. Methods such as transferring the shape of the master groove have been adopted.

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

10...Wafer chamfering device 11...Main body base 20...Wafer feeding unit 21...X-axis base 22...X-axis guide rail 23...X-axis linear guide 24...X-axis 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...Truer 50...Whetstone rotation unit 51...Outer grindstone spindle 52 ...Outer circumference rough grinding wheel 53...Turntable 54...Outer circumference fine grinding spindle 55...Grinding whetstone 56...Outer circumference fine grinding motor 60...Master grindstone 61...First groove 62...Second groove 81...Straight section 82...Slope section 83...R Shape 84...Cross-sectional shape 85...Cross-sectional shape CW...Wafer table rotation axis GC...Disc shape W...Wafer n...Surface width

Claims (11)

A truer forming method in truing in which a groove of a grindstone for grinding a chamfered portion of a wafer is formed by a disc-shaped truer, the method comprising:
A step A of adjusting the diameter and rough shape of the truer using a master grindstone for shaping the truer;
A step B of forming the edge of the truer into a target shape,
The step A and the step B are performed using each of a plurality of master grooves of different shapes that the master grindstone has, or
The truer forming method, wherein the step A and the step B are performed using each of different shaped portions of at least one master groove of the master grindstone. The step A and the step B are:
The true forming method according to claim 1, wherein the method is performed using a first groove and a second groove, which are the master grooves of different shapes of the master grindstone. The truer forming method according to claim 2,
A truer forming method, characterized in that after the truer is processed in the first groove, edge processing is performed using the tip of the second groove. The truer forming method according to claim 2,
A truer forming method characterized in that the tip of the second groove has a radius of a radius larger than that of the first groove. The truer molding method according to any one of claims 2 to 4,
A truer forming method, characterized in that when chamfering the trueer in the master groove, the machining is performed in a direction in which the trueer is pulled. The truer forming method according to claim 3,
A truer forming method, characterized in that corner radius processing is performed by reducing the moving distance of the truer to modify the shape, radius, and roundness of the corner by using the tip of the second groove. The truer forming method according to claim 6,
A truer forming method characterized in that after the corner R processing of the upper surface (upper surface) is completed, the corner R processing of the lower surface (lower surface) is performed. The truer forming method according to claim 7,
The parameters of the movement start point (approach point, approach speed), machining speed, escape position, escape speed, rotation speed of the truer, machining start point, and machining end point are the corner R machining (top surface) and the corner R machining (top surface). The truer molding method is characterized in that it is carried out by taking two values: (lower surface). The truer forming method according to claim 8,
A truer forming method characterized in that each processing is independently set as an amplitude, the processing speed, a spark-out time, and a number of reciprocations as a traverse operation. The step A and the step B are:
carried out using each of different shaped portions of at least one master groove of the master whetstone,
The true molding method according to claim 1, wherein the step B is performed using the tip end of the master groove. The true molding method according to claim 10, wherein the step A is performed using the bottom of the master groove.

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