JP7128309B2 - Chamfered substrate manufacturing method and chamfering apparatus used therefor - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing a highly accurate chamfered substrate at the end face of various materials such as silicon, sapphire, compounds, and glass, particularly semiconductor wafers, glass panels, and other plate-shaped workpieces. It is suitable for processing the end face of a workpiece having a linear portion other than a circular shape.

In recent years, there has been a strong demand for improved quality of wafers, and the processing state of the wafer end face (edge portion) has been emphasized. Chamfering is performed by grinding the edge, and mirror-like chamfering is performed by polishing. In other words, in the semiconductor manufacturing process, from wafer manufacturing to device manufacturing, quality improvement of edge characteristics is an essential process.

Silicon and other materials are hard and brittle, and if the edge of the wafer remains sharp during slicing, it can easily break or chip during handling such as transportation and positioning in subsequent processing steps, and the fragments can damage or contaminate the wafer surface. or In order to prevent this, the end face of the cut wafer is chamfered with a diamond-coated chamfering whetstone. At this time, it also includes adjusting the diameter of the outer circumference, which varies, adjusting the width of the orientation flat (OF), and adjusting the size of a very small notch called a notch.

In addition, for the glass substrates used in smartphones and tablets, where thinning and weight reduction are pursued, masking printing, formation of sensor electrodes, and then cutting are carried out. The occurrence of microcracks and the like directly affects the edge strength of the glass substrate.

Furthermore, in normal grinding, the chamfered portion is ground with the main surface of the wafer W perpendicular to the rotation axis of the resin grindstone. Therefore, it is known to perform so-called helical grinding, in which, for example, a resin bond grindstone (resin grindstone) is tilted with respect to the wafer to grind the chamfered portion of the wafer.

When helical grinding is performed, not only does processing strain on the chamfered portion be reduced compared to normal grinding, but also the contact area between the chamfered portion of the wafer and the grindstone is increased to improve the surface roughness of the chamfered portion.

Furthermore, when the chamfered portion of a semiconductor wafer is helically ground with a resin grindstone or the like, continuous processing of the chamfered portion gradually changes the vertical angle of the groove of the resin grindstone, resulting in a further asymmetry of the chamfered portion of the wafer. growing. Therefore, the edge of the disk-shaped lure is ground by the groove of the first whetstone having a vertically asymmetric groove formed around it, and the edge of the disk-shaped lure is formed into a vertically asymmetric groove shape. The whetstone is relatively tilted to form a groove around the second whetstone, and the wafer is relatively tilted with respect to the groove direction by the second whetstone to obtain a substantially symmetrical resin whetstone, followed by chamfering. It is known to finely grind the part and is described, for example, in US Pat.

In addition, in a chamfering method in which the rotation axis of the grindstone for chamfering is inclined at a predetermined angle with respect to the rotation axis of the wafer, it is known to form processing grooves for the outer peripheral portion of the wafer and the OF portion on the outer peripheral grinding wheel. It is described in Reference 2.

Furthermore, it is known to relatively move the grindstone in the thickness direction of the wafer during chamfering in order to keep the chamfering width of the notch portion constant.

JP 2007-165712 A JP-A-2007-21586 JP 2005-153129 A

In the prior art described above, the one described in Patent Document 1 requires a first grindstone around which grooves having a vertically asymmetrical shape are formed, and it is difficult to determine the shape of the first grindstone. In the case of a circular wafer, the shape can be uniquely determined because the same shape is sufficient for the entire circumference. When there is a part and a non-circular part, not only is it more difficult, but the change in the vertical angle of the groove of the resin grindstone also increases at the position where the circular part moves to the non-circular part and at the corners, and the entire circumference must be helically ground. was extremely difficult to do. In other words, at the corners of the substrate (work) having corners, only one of the upper surface and the lower surface of the groove of the grindstone was hit, and good chamfering was not possible.

The method described in Patent Literature 2 complicates the grinding process and is good for circular parts with few non-circular parts, but is difficult to apply to rectangular or polygonal parts.

In the method disclosed in Patent Document 3, since the grindstone must be moved relatively in the thickness direction of the wafer during chamfering, it is necessary to control the wafer or the grindstone in the thickness direction in order to improve the chamfering accuracy. It was complicated and difficult.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a helical wafer substrate having an OF (orientation flat), a rectangular or polygonal wafer, a substrate, a cover glass, or the like, even if it has a circular portion and a non-circular portion. To facilitate grinding, increase the contact area between a workpiece and a grindstone, improve the surface roughness, and improve shape collapse.

In order to achieve the above object, the present invention provides a chamfered substrate manufacturing method for grinding an end surface of a plate-shaped workpiece having corners and straight portions with a grinding groove of a grinding wheel, the method comprising: A chuck table smaller than the outer peripheral shape of the workpiece is used to suck the plane in the thickness direction, and the rotation axis of the grinding wheel is tilted with respect to the axis in the thickness direction perpendicular to the plane of the workpiece. , the grinding groove is pressed against the end surface of the workpiece in the vertical direction and abutted thereon, the upper chamfered portion of the workpiece is in contact with the upper slope of the ground groove, and the lower chamfered portion of the workpiece is Grinding the upper chamfered portion on the upper sloped surface without contacting the lower sloped surface of the grinding groove is continuously performed on the entire circumference including the corners of the end surface of the workpiece, and then the grinding wheel. is relatively raised in the thickness direction with respect to the work material so that the lower chamfered portion of the work material contacts the lower sloped surface and the upper chamfered portion does not contact the upper sloped surface. The chamfered portion of the lower portion of the workpiece is ground on the inclined surface of the lower surface by continuously grinding the entire circumference including the corners of the end surface of the workpiece, or the chamfered portion of the lower portion of the workpiece is ground on the inclined surface of the lower surface. The lower chamfered portion of the workpiece is ground on the lower sloped surface so that the upper chamfered portion of the workpiece does not contact the upper sloped surface, and the entire circumference including the corners of the end surface of the workpiece is ground. After that, the grinding wheel is lowered relative to the workpiece in the thickness direction so that the upper chamfered portion of the workpiece contacts the upper sloped surface, and the lower chamfered portion is The chamfered portion of the upper portion is continuously ground on the upper sloped surface so that the chamfered portion does not come into contact with the lower sloped surface .

In the above, it is preferable that the width of the grinding groove is made larger than the apparent thickness of the workpiece when the rotation axis of the grinding wheel is tilted.

Further, in the above, the upper part of the end face of the workpiece is ground by the grinding groove, and then the grinding wheel is raised in the thickness direction relatively to the workpiece and ground again, or It is preferable that the lower part of the end surface of the workpiece is ground by the grinding groove, and then the grinding wheel is lowered relative to the workpiece in the thickness direction to grind the workpiece again.

Further, in the above, the upper or lower part of the end surface of the workpiece is ground over the entire circumference so as to make one round with the grinding groove, and then the grinding wheel is moved relatively to the workpiece. It is preferable to raise or lower in the thickness direction and further grind one round.

Furthermore, in the above, it is preferable to incline the rotation axis of the grinding wheel by 3 to 15 degrees.

Furthermore, in the above, it is preferable that the processing of the end face of the work material is performed by grinding the upper part, the center part, and the lower part of the end face of the work material, respectively.

Further, in the above, it is preferable that the grinding of the upper portion, the grinding of the central portion, and the grinding of the lower portion be performed so as to make one turn along the grinding groove over the entire circumference of the end surface of the workpiece.

Further, the present invention provides a chamfering device for chamfering an end surface of a plate-shaped work piece having corners and straight portions with a grinding groove of a grinding wheel, wherein the flat surface of the work piece is sucked in the thickness direction, A chuck table that is smaller than the outer peripheral shape of the workpiece, and a rotation axis that is tilted with respect to the axis in the thickness direction that is perpendicular to the plane of the workpiece, so that the grinding groove is perpendicular to the end surface of the workpiece. a chamfered portion of the upper portion of the workpiece contacts the upper sloped surface of the grinding groove, and a chamfered portion of the lower portion of the workpiece contacts the lower sloped surface of the grinding groove. Grinding the chamfered portion of the upper part on the upper slope without contacting the workpiece is continuously performed on the entire circumference including the corners of the end face of the workpiece, and then the grinding wheel is applied to the workpiece. The lower chamfered portion of the workpiece is relatively raised in the thickness direction so that the lower chamfered portion of the workpiece contacts the lower sloped surface, and the upper chamfered portion does not contact the upper sloped surface. Grinding on the lower sloped surface is continuously performed on the entire circumference including the corners of the end surface of the workpiece, or the chamfered portion of the lower part of the workpiece contacts the lower sloped surface, and the workpiece Grinding the chamfered portion of the lower portion on the inclined surface of the lower surface so that the chamfered portion of the upper portion of the material does not contact the inclined surface of the upper surface is continuously performed around the entire circumference including the corners of the end surface of the workpiece, and then and lowering the grinding wheel relative to the workpiece in the thickness direction so that the upper chamfered portion of the workpiece contacts the upper sloped surface and the lower chamfered portion contacts the lower sloped surface. The chamfered portion of the upper portion is ground on the inclined surface of the upper surface so as not to be in contact with each other, and the whole circumference including the corners of the end surface of the workpiece is continuously performed .

Furthermore, in the above-mentioned apparatus, it is preferable that the width of the grinding groove is made larger than the apparent thickness of the workpiece when the rotation axis of the grinding wheel is tilted.

Further, in the above, the upper part of the end surface of the workpiece is ground with the grinding groove, and then the grinding wheel is raised in the thickness direction relative to the workpiece and ground again; Alternatively, it is preferable to grind the lower part of the end face of the workpiece with the grinding groove, and then lower the grinding wheel relative to the workpiece in the thickness direction to grind the workpiece again.

Further, in the above-described one, the upper or lower part of the end surface of the workpiece is ground over the entire circumference so as to make one round with the grinding groove, and then the grinding wheel is placed relative to the workpiece. It is preferable to raise or lower in the thickness direction and then grind one round.

Further, in the above, it is preferable that the rotation axis of the grinding wheel is tilted by 3 to 15 degrees.

Further, in the above-described device, it is preferable that the end face of the workpiece be processed by grinding the upper part of the end face, grinding the center part, and grinding the lower part of the end face.

According to the present invention, even a rectangular or polygonal workpiece can be helically ground, the surface roughness can be improved, and the shape deformation can be reduced.

1 is a plan view showing the main parts of a chamfering device according to one embodiment of the present invention; FIG. FIG. 2 is a perspective view showing the configuration of a processing portion according to one embodiment (workpieces are circular and linear portions); Plan view in FIG. FIG. 2 is a perspective view showing the configuration of a processing portion in one embodiment (the workpiece is mainly a straight portion); Plan view in FIG. FIG. 4 is a plan view for explaining the contact between the workpiece and the upper and lower ends of the grinding wheel; Perspective view showing conventional helical grinding for edge processing of plate material Side view for explaining the difference between conventional grinding and grinding according to one embodiment FIG. 2 is a side view showing an end face of a workpiece processed by a chamfered substrate manufacturing method according to one embodiment; Side view showing a method for manufacturing a chamfered substrate according to another embodiment FIG. 2 is a side view showing details of a grinding wheel and a workpiece according to an embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the drawings. The invention is not limited by these embodiments, and the constituent elements in the embodiments include those that can be easily assumed by those skilled in the art, or those that are substantially the same.

FIG. 1 is a plan view showing the main part of a chamfering device according to one embodiment of the present invention. The chamfering apparatus mainly has a supply/recovery section 20 and a processing section 10, and also includes a pre-alignment section, a cleaning section, a post-measurement section, a transfer section, and the like (not shown).

Wafer processing steps are performed in the order of slicing→chamfering→lapping→etching→donor killer→precision chamfering, and various types of cleaning are used between the steps to remove dirt. Silicon, etc. is hard and brittle, and if the edge of the wafer remains sharp during slicing, it can easily break or chip during handling such as transportation and alignment in subsequent processing steps, and the fragments can damage or contaminate the wafer surface. or In order to prevent this, in the chamfering step, the end face of the cut wafer is chamfered with a diamond-coated chamfering grindstone.

The chamfering process may also be performed after the lapping process. At this time, the diameter of the outer periphery, which varies, is adjusted, the width of the orientation flat (OF) is adjusted, and the dimensions of minute cutouts called notches are adjusted.

The supply/recovery unit 20 supplies the wafers W to be chamfered from the wafer cassette 30 to the processing unit 10 and recovers the chamfered wafers to the wafer cassette 30 . This operation is performed by the supply/collection robot 40 . A wafer cassette 30 is set on a cassette table 31 and contains a large number of wafers W to be chamfered. The supply/recovery robot 40 takes out the wafers W one by one from the wafer cassette 30 and stores chamfered wafers in the wafer cassette 30 .

The supply/recovery robot 40 has a three-axis rotating transfer arm 50, and the transfer arm 50 has a suction pad (not shown) on its upper surface. The transport arm 50 holds the wafer W by vacuum-sucking the rear surface of the wafer W with a suction pad. That is, the transfer arm 50 of the supply/recovery robot 40 can move back and forth, move up and down, and turn while holding the wafer W. The wafer W is transferred by combining these movements.

The processing unit 10 is arranged in the front part of the wafer chamfering apparatus, and performs all processing of chamfering the outer circumference of the wafer W, that is, from rough processing to finishing processing. The processing section 10 comprises a wafer feeding device 60 , an outer circumference rough grinding device 62 , a transfer arm 63 for conveying the wafer W, and an outer circumference fine grinding device 61 .

2 is a perspective view showing the configuration of the processing unit 10, and FIG. 3 is a plan view. The chuck table 66 is driven by drive means (not shown) to move in the front-back direction (Y-axis direction), the left-right direction (X-axis direction), and the up-down direction (Z-axis direction). It rotates around the central axis (θ axis) by being driven by the table driving motor 65 .

The outer circumference rough grinding device 62 is arranged at a position apart from the chuck table 66 of the wafer feeding device 60 by a predetermined distance in the Y-axis direction. The outer circumference rough grinding device 62 has an outer circumference rough grinding spindle 68 driven by an outer circumference rough grinding motor 67 to rotate. The outer circumference rough grinding spindle 68 is configured to be movable in the front-rear direction (Y-axis direction) and the vertical direction (Z-axis direction) by being driven by a driving means (not shown).

An outer circumference rough grinding grindstone 69 for roughing (roughly grinding) the outer circumference of the wafer W is mounted on the outer circumference rough grinding spindle 68, and serves as the rotating shaft. The outer periphery rough grinding wheel 69 has a plurality of outer periphery rough grinding grooves formed on its outer peripheral surface (formed wheel). rough grinding).

The peripheral fine grinding device 61 is arranged at a position separated from the chuck table 66 of the wafer feeding device 60 by a predetermined distance in the X-axis direction. This peripheral fine grinding device 61 has an outer peripheral fine grinding spindle 71 that is rotated by being driven by a peripheral fine grinding motor 70 . The outer periphery precision grinding spindle 71 is configured to be movable in each of the left-right direction (X-axis direction) and the up-down direction (Z-axis direction) by being driven by a driving means (not shown). An outer periphery precision grinding wheel 72 for finishing (precision grinding) the outer periphery of the wafer W is mounted on the outer periphery fine grinding spindle 71, and serves as the rotating shaft.

The outer periphery fine grinding wheel 72 has a groove for outer periphery precision grinding formed in its outer peripheral surface (formed wheel), and the outer periphery of the wafer W is finished by pressing the outer periphery of the wafer W against this groove.

At this time, the wafer is ground by helical grinding in a state in which the rotation axis of the outer circumference precision grinding spindle 71 is inclined with respect to the rotation axis of the chuck table 66 in the tangential direction of the outer circumference of the wafer W by 3 to 15°, preferably 6 to 10°. Perform finish machining for chamfering the outer periphery of W.

As a result, the direction of movement of the abrasive grains intersects with the direction of movement of the outer periphery of the wafer W, and the contact area increases. The roughness of the machined surface (grinding surface) is improved.

Next, the operation of the processing section 10 will be described. In a standby state before starting processing, the wafer W held on the chuck table 66 is arranged so that its center coincides with the rotation axis of the chuck table 66 . At this time, the OF portion of the wafer W is arranged so as to face a predetermined direction (the Y-axis direction in this example).

Further, the outer circumference rough grinding wheel 69 and the outer circumference fine grinding wheel 72 are located at positions separated from the wafer W by a predetermined distance. Specifically, the center of rotation of the outer circumference rough grinding wheel 69 is located at a predetermined distance in the Y-axis direction from the center of rotation of the wafer W, and the center of rotation of the outer periphery fine grinding wheel 72 is positioned with respect to the wafer W. They are arranged at positions separated by a predetermined distance in the X-axis direction.

First, an alignment operation is performed. In this alignment operation, the relative positional relationship between the wafer W held on the chuck table 66 and the outer circumference rough grinding wheel 69 and the outer circumference fine grinding wheel 72 is adjusted in the vertical direction (Z-axis direction).

When the alignment operation is completed, the outer circumference coarse grinding motor 67 is driven. Next, grinding (rough processing) by the outer peripheral rough grinding wheel 69 is started. Specifically, the Y-axis motor (not shown) of the outer periphery rough grinding device 62 is driven, and the outer periphery rough grinding spindle 68 is sent toward the chuck table 66 along the Y-axis direction.

As the outer circumference rough grinding wheel 69, for example, a metal bond wheel with diamond abrasive grains having a diameter of 202 mm and a grain size of #800 can be used. The outer circumference rough grinding spindle 68 is a spindle driven by a built-in motor using ball bearings, and is rotated at a predetermined rotational speed, for example, a rotational speed of 8,000 rpm.

When the outer circumference rough grinding spindle 68 is fed toward the chuck table 66, the outer circumference of the wafer W comes into contact with the grinding groove for outer circumference rough grinding formed in the outer circumference rough grinding grindstone 69, and the outer circumference of the wafer W is subjected to the outer circumference rough grinding. After being ground by the grindstone 69, the rough processing of chamfering the outer periphery of the wafer W is started.

After the rough processing by the outer circumference rough grinding wheel 69 is started, the wafer W held on the chuck table 66 starts rotating at a constant speed in the direction of the arrow since the wafer W in FIG. 2 is circular at first. When this rotation angle, that is, the processing point reaches the OF portion where the processing point is a straight portion, the feed amount of the outer circumference rough grinding spindle 68 in the direction toward the chuck table 66, which is the Y direction, is increased, and the outer circumference rough grinding spindle 68 is moved to the X direction. Move linearly in the direction to process the linear part. After that, when the processing of the linear portion is completed, the plate-shaped wafer W held on the chuck table 66 is rotated again at a constant speed in the direction of the arrow, and the remaining circular portion is ground and rough-processed by the outer circumference rough grinding wheel 69. exit.

Next, finish processing is performed in the same manner by the outer peripheral precision grinding wheel 72 . As the peripheral precision grinding wheel 72, a resin-bonded wheel with diamond abrasive grains is suitable. Further, the outer peripheral chamfering of the wafer W is performed while the rotating shaft of the outer periphery precision grinding spindle 71 is inclined with respect to the rotating shaft of the chuck table 66 in the tangential direction of the outer periphery of the wafer W by 3 to 15 degrees, preferably 6 to 10 degrees. Finishing is done.

Furthermore, although the processing groove for chamfering of the outer peripheral precision grinding wheel 72 is formed by a truer, detailed description thereof will be omitted. As the outer circumference rough grinding wheel 69, for example, a metal powder such as Fe, Cr, Cu or the like is used as a main component, mixed with diamond abrasive grains and formed. A material that can be processed by the outer peripheral rough grinding wheel 69 and that can be ground by the outer peripheral fine grinding wheel 72 is adopted as the material of the truer.

For example, it is preferable that abrasive grains made of silicon carbide are combined with a phenolic resin, if necessary, with a filler or the like added, and formed into a disk-shaped lure. The outer peripheral fine grinding wheel 72 is made of a material that can form a grinding groove 74 around it by grinding with a truer, and that can finely grind the chamfered portion of a silicon wafer or the like by the formed grinding. For example, it is desirable to use phenol resin, epoxy resin, polyimide resin, polystyrene resin, polyethylene resin, or the like as the main component, mixed with diamond abrasive grains or cubic boron nitride abrasive grains.

As the peripheral precision grinding wheel 72, for example, a resin-bonded wheel with diamond abrasive grains having a diameter of 50 mm and a grain size of #3000 is used. The peripheral fine-grinding spindle 71 is a built-in motor-driven spindle using an air bearing, and is rotated at a rotational speed of 35,000 rpm.

FIG. 4 is a perspective view showing the configuration of the processing portion when the workpiece is not circular but rectangular, and FIG. 5 is a plan view of the same. When the workpiece is not circular but rectangular, as shown in FIGS. 4 and 5, the straight portion is mainly processed.

As smartphones and tablets become thinner and lighter, glass substrates, cover glass, sapphire, and ceramics are used for the surface, and edge strength is important. is required. The processing quality of chamfering, the roughness of the processed surface, the generation of microcracks, etc., directly affect the edge strength of the glass substrate.

4 and 5 show the chamfering of a rectangular glass panel in a smart phone or tablet, the X-axis motor (not shown) of the peripheral precision grinding device 61 is driven, and the peripheral precision grinding spindle 71 is moved along the X-axis direction. It is sent toward the chuck table 73 .

When the peripheral precision grinding spindle 71 is fed toward the chuck table 73 , the straight portion of the glass panel (or wafer) W comes into contact with the peripheral precision grinding groove, which is a chamfering processing groove formed in the peripheral precision grinding wheel 72 . , the outer periphery of the glass panel W is helically ground by the outer periphery precision grinding wheel 72, and the processing of chamfering the outer periphery of the glass panel W is started. Since the glass panel W shown in FIGS. 4 and 5 is rectangular, the glass panel W held by the chuck table 73 starts to move at a constant speed in the Y-axis direction after the processing by the outer peripheral precision grinding wheel 72 is started. When the machining point reaches the corner, the chuck table 73 rotates 90° and moves in the Y-axis direction to machine the next straight part. Thereafter, the entire outer circumference of the glass panel W is similarly processed.

In addition, the grinding wheel is made by impregnating a chamfering grinding wheel material having a porous surface with a saturated fatty acid solution and a lubricant, drying the surface to obtain a lubricant-impregnated grinding wheel, and using the grinding wheel containing this lubricant after water cooling during grinding. It is desirable to As a result, the lubricant is reliably supplied to the cutting point of the grindstone, and the cutting point temperature can be kept below the predetermined temperature. Moreover, since water is used as the cooling liquid, environmental pollution due to the cooling liquid can be prevented. Furthermore, in the wafer chamfering apparatus, since the grindstone is impregnated with a lubricant, the lubricant can be supplied to the cutting point for a long period of time.

The chuck table 73 has the same shape as the rectangular glass panel W as shown in FIG. It becomes sufficiently small, and the glass panel W is held overhanging from the chuck table 73 .

Specifically, the size of the chuck table 73 is defined as Q=(1 .3 to 1.7) P, more preferably Q=1.5P, is preferable from the standpoint of fixation by adsorption of the glass panel W and grinding. In other words, deformation, deflection, and distortion of the glass panel W are avoided, and the glass panel W itself is slightly elastically deformed during processing, and the peripheral precision grinding wheel 72 is a soft resin-bonded wheel. Combined with that, the shock such as vibration is mitigated. The same applies to the Y-axis direction, and N=(1.3 to 1.7)H in FIG. 5, preferably N=1.5H. In other words, it is desirable that the shape of the chuck table 73 is smaller than the outer peripheral shape of the workpiece, and 0.6 to 0.8 times the plane shape of the glass panel W in both length and width. The shape of the rectangular glass panel W is about 120 mm×60 mm in length×width and about 0.5 to 1.5 mm in thickness, and the rectangular chuck table 73 is preferably about 80 mm×40 mm.

Since the rotation axis of the peripheral precision grinding spindle 71 is inclined with respect to the chuck table 73 in the tangential direction of the periphery of the glass panel W by θ=3 to 15°, preferably 6 to 10°, the glass panel W is finely ground on the periphery. Abutting against the grinding groove 74 of the grindstone 72 at this angle θ, the moving direction of the abrasive grains intersects with the moving direction of the glass panel W. On the other hand, if the angle of inclination is too large, it is not preferable in terms of increased grinding resistance, chipping of the upper and lower corners of the end surface, scratches, and the like.

The width y of the grinding groove 74 of the outer periphery precision grinding wheel 72 is determined from the position where the upper end of the grinding groove 74 contacts the upper surface of the workpiece W when the grinding groove 74 of the outer periphery precision grinding wheel 72 is inclined by an angle θ. The distance to the position where the lower surface of the workpiece W is closest to the lower end of the grinding groove 74 but does not contact it, that is, the apparent thickness of the workpiece when the grinding groove 74 is inclined at an angle θ, the left end from the right end y>y0, which is wider than the dimension y0 to Assuming that the diameter of the grinding groove 74 is D and the thickness of the workpiece W is t, y0 is approximately Dtan θ+t/cos θ. As for the method of widening the grinding groove 74, the groove for transfer during tooling may be widened in advance, or the tool may be moved up and down in the Z-axis direction during tooling to widen the grinding groove 74. can be

Next, a processing procedure for helical grinding will be described below.
Referring to FIG. 10, when the outer peripheral precision grinding spindle 71 is sent toward the chuck table 73, the upper surface slope 72u of the upper right end of the grinding groove 74 contacts the upper surface of the glass panel W and the upper right end to be machined. is started, and then the glass panel W held on the chuck table 73 is moved in the Y-axis direction at a constant speed to be chamfered.

Since the ground groove 74 is wider than the apparent thickness of the glass panel W, the lower surface of the glass panel W does not come into contact with the lower surface. The central portion and main portion of the glass panel W in the thickness direction are helically ground in contact with the peripheral portion of the grinding groove 74 of the outer peripheral precision grinding wheel 72 . When the processing point reaches the rounded corner portion of the glass panel W, the chuck table 73 rotates to process the rounded corner portion. At this time, it is the same as grinding a circular portion, and since the contact area becomes small, the contact of the upper surface slope of the ground groove 74 becomes weak, and the central portion in the thickness direction is mainly ground. Thereafter, processing is continued in the same manner until the outer periphery of the glass panel W is made one round.

At the point where the above processing has completed one round , the outer peripheral fine grinding wheel 72 is raised in the Z-axis direction, or the chuck table 73 is lowered in the Z-axis direction, and the lower surface slope of the grinding groove 74 is the lower surface of the glass panel W , the left side. 72 d of lower surface slopes of a lower end part contact|abut. That is, the grinding wheel is raised in the thickness direction relative to the workpiece. After that, the glass panel W held on the chuck table 73 is moved in the X-axis direction at a constant speed to perform the chamfering of the second round.

Since the grinding groove 74 is wider than the apparent thickness of the glass panel W, the upper surface of the glass panel W does not come into contact with it. The central portion and main portion of the glass panel W in the thickness direction are helically ground in contact with the peripheral portion of the grinding groove 74 of the outer peripheral precision grinding wheel 72 .

As described above, the grinding groove 74 of the outer periphery precision grinding wheel 72 is inclined at an angle θ and abuts against the glass panel W so that the movement direction of the abrasive grains intersects the movement direction of the glass panel W, and The width of the grinding groove 74 of the outer periphery precision grinding wheel 72 is made wider than the apparent thickness of the workpiece when the outer periphery fine grinding wheel 72 is tilted with respect to the workpiece by an angle θ. By moving up and down in the axial direction, it is possible to apply helical grinding to the chamfering of materials such as linear portions such as OFs, and rectangular and polygonal shapes. As a result, the surface roughness of the end face and processing strain are reduced, and even a high-grit grindstone can be used for a long time.

Here, the present inventor made the angle θ larger so that the upper right end of the upper surface of the glass panel W abuts against the upper sloped surface 72u, and the lower left end of the lower surface of the glass panel W abuts against the lower sloped surface 72d. An evaluation was carried out in which grinding was performed in contact with each other. Then, when grinding the corners of the glass panel W, it was found that the glass panel W always comes into contact with only one of the upper slope 72u and the lower slope 72d. For this reason, it has been found that at the corners of the glass panel W, either the upper surface or the lower surface is always insufficiently ground.

Therefore, when performing helical polishing, the inventor believes that the relationship between θ 1 , y, and the thickness t of the glass panel W is such that "only one of the upper surface and the lower surface of the glass panel W is the edge of the grinding groove 74 (the upper surface We have found that θ, y, t must be chosen such that the slope 72u or the lower slope 72d) is in contact and the other is not in contact with the edge” (Condition 1). Therefore, if any of these parameters are fixed, Condition 1 above must be satisfied by adjusting the changeable parameters. At that time, it was found that it is preferable for y0 to be a value as close to y as possible within the range that satisfies condition 1. This is because most of the grinding grooves 74 can be used, and the life of the grindstone is extended.

FIG. 6 is a plan view for explaining the difference in abutment between the outer periphery precision grinding wheel 72 and the grinding groove 74 at the upper and lower ends in the thickness direction of the glass panel W between processing the circular portion and processing the straight portion. The contact area between the cylindrical portion of the grinding groove 74 of the precision grinding wheel 72 and the linear workpiece W1 is not only larger than the contact area between the cylindrical portion and the circular workpiece W2, but also the upper inclined surface 72u or the lower inclined surface 72d of the upper and lower ends of the grinding groove 74. The contact area L of the straight work W1 with is larger than the contact area M of the circular work W2.

Therefore, not only is the grinding resistance of the linear workpiece W1 greater than that of the circular workpiece W2, but if the width of the grinding groove 74 in the thickness direction is matched to the circular workpiece W2, the linear workpiece W1 can be chamfered. become unable. Further, even if the grinding grooves 74 are formed so that the circular work W2 can be chamfered vertically symmetrically, the chamfering of the straight work W1 results in different top and bottom shapes.

FIG. 7 shows an example of helical grinding by an axis tilting method in which one axis is added to a surface grinding machine 80 for conventional end surface processing of a plate material. As shown in FIG. 7 , the precision stage 81 is arranged at an inclination angle α so that the workpiece 83 passes through the lowest point of the grindstone 82 . The whetstone 82 is wider than the material 83 to be processed, and is fixed on both sides by a vise 84 close to the surface to be processed.

In this method, as shown in FIG. 8(a) , the work piece 83 is firmly fixed by a vise 84, and the rotation axis of the grindstone 82 is parallel to the processing surface. It is pressed in the direction of arrow V, and vibration of the grindstone 82 or the like impacts the material 83 to be processed and damages the surface to be processed. In addition, since the chip by grinding falls on the processing surface, scratches caused by the chip and streaks caused by scratching are generated on the processing surface.

On the other hand , in the present invention, the grinding groove 74 of the outer peripheral precision grinding wheel 72 is inclined at an angle θ with respect to the workpiece W. As shown in FIG. The flat surface of the glass panel W is placed on the chuck table 73, and the pressure of this surface is reduced by an air compressor, a blower, or the like, and the glass panel W is adsorbed and fixed. In the case of FIG. 8B , in which the glass panel W is overhanged from the chuck table 73 and held by suction in the vertical direction, the grinding groove 74 of the outer periphery fine grinding wheel 72 is in vertical contact with the processing surface, and the outer periphery is precisely ground. A pressing force by the grinding wheel 72 works as indicated by an arrow H.

Therefore, the material to be processed, for example, the glass panel W itself is slightly elastically deformed during processing, and together with the fact that the peripheral precision grinding wheel 72 is a soft resin-bonded wheel, the impact such as vibration is mitigated. Therefore, there is no damage such as scratches on the machined surface, and the chips produced by grinding are discharged as shown by the arrow, and do not fall on the machined surface. There is no

FIG. 9 is a side view showing an end face of a workpiece processed by the method for manufacturing a chamfered substrate described above, and the state of streaks after grinding with the outer peripheral fine grinding wheel 72, which is a resin wheel, is shown by oblique lines. . The grinding groove 74 has a sufficiently large width relative to the thickness of the workpiece (substrate, work), and is brought into contact with the workpiece at an oblique angle of 6 to 10°. Chamfering was performed so that only one side was in contact with the work and the other side was not in contact. In practice, grinding with the upper surface in contact was carried out once around the entire circumference of the end face of the workpiece, then the lower surface was brought into contact with the workpiece, and then another round was carried out to perform a total of two rounds of polishing and chamfering. .

In the chamfering process by conventional helical grinding, it was not possible to perform good chamfering because only one of the upper and lower surfaces of the grinding groove of the grindstone hit hard on the work piece with corners and straight parts. As shown, the central portion C in the thickness direction becomes a peculiar streak of helical grinding according to the angle at which the grindstone is inclined, and the surface roughness is good and the shape does not collapse.

In addition, both the upper and lower ends are symmetrical in terms of angle and size, and the widths of Tu and Td in the figure are also uniform. The direction differs by the amount of contact of the edge of the ground groove, which is clearly shown.

Furthermore, as smartphones and tablets become thinner and lighter, conventionally, the glass substrate is cut to a predetermined size, chemically strengthened, and then masked and printed to form sensor electrodes. . On the other hand, according to the method for manufacturing a chamfered substrate, even if a large glass substrate is chemically strengthened as it is, masking printing is performed, sensor electrodes are formed, and then cutting and chamfering are performed. In other words, even when the end face is not chemically strengthened, a good machined surface roughness can be obtained, and the occurrence of microcracks can be suppressed. As a result, production efficiency is significantly improved, and practically sufficient end face strength can be obtained.

Furthermore, not only the surface roughness and shape symmetry, but also the reduction in grinding ability after one time correction (tooling) of the grinding groove, the predetermined outer peripheral surface width, outer peripheral angle, and outer peripheral shape are not satisfied. Also, the number of sheets that can be processed can be increased. Furthermore, when the resin grindstone 72, which is a resin grindstone, is repeatedly tooled and chamfered continuously, the diameter of the resin grindstone becomes less than a predetermined diameter due to wear, and the number of sheets that can be processed increases before it becomes unusable. be able to.

Although helical grinding using the outer periphery fine grinding wheel 72 has been described above, helical grinding may be performed in two turns during rough grinding, that is, when the outer periphery rough grinding wheel 69 is used. According to this, it is possible to prevent wear, clogging, and deformation of the groove shape of the grinding groove 74 of the outer peripheral fine grinding wheel 72 during fine grinding, and perform better chamfering.

In addition, the upper part of the end surface of the workpiece is ground over the entire circumference so as to make one round with the grinding groove 74 (upper grinding), and then the grinding wheel 69 or 72 is moved relative to the thickness direction of the workpiece. and then grind the lower part one round (grinding of the lower part), but this order may be reversed, and the upper surface slope, which is the end of the grinding groove 74, is formed on the upper and lower parts of the end surface of the workpiece. Grinding of the central portion, which does not contact with neither 72u nor the lower slope 72d, may be performed separately.

FIG. 10 shows the central grinding . Grinding of the central portion is performed when the chuck table 73 is fed toward the outer periphery precision grinding spindle 71, and the upper slope 72u at the upper right end of the grinding groove 74 and the lower slope 72d at the lower left end of the grinding groove 74 both face the glass panel W. Processing is started without contacting the upper and lower surfaces, and then the glass panel W held by the chuck table 73 is moved at a constant speed in the Y-axis direction to be chamfered. When the grinding groove 74 has an apparent thickness y 0 of the glass panel W, that is, when the grinding groove 74 of the outer peripheral precision grinding wheel 72 is inclined at an angle θ, the diameter of the grinding groove 74 is D, and the thickness of the glass panel W as the work material. It is at least 20-30% wider than the thickness considering both t.

The central portion and main portion of the glass panel W in the thickness direction are helically ground in contact with the peripheral portion of the grinding groove 74 of the outer peripheral precision grinding wheel 72 . When the processing point reaches the rounded portion of the corner, the chuck table 73 is rotated to process the rounded portion of the corner. Since the edge in the thickness direction of the glass panel W is not ground by the upper and lower slopes (or the upper and lower ends) of the grinding groove 74, it is suitable for processing regardless of the outer peripheral shape of the glass panel W without affecting the vertical asymmetry. 2, it is convenient for cutting out the shape when the circular portion is the main component and the linear portion such as the OF portion is present.

From the state of FIG. 10 , the outer peripheral fine grinding wheel 72 is lowered in the Z-axis direction, or the chuck table 73 is raised in the Z-axis direction, and the upper surface of the glass panel W is placed on the upper surface slope 72u at the upper right end of the grinding groove 74, which is the upper right in the figure. Abut the ends. That is, the grinding wheel is lowered in the thickness direction relative to the workpiece. After that, the glass panel W held on the chuck table 73 is moved in the Y-axis direction at a constant speed to be chamfered by helical grinding.

The outer peripheral precision grinding wheel 72 is raised in the Z-axis direction, or the chuck table 73 is lowered in the Z-axis direction, so that the lower slope of the grinding groove 74 contacts the lower surface of the glass panel W, which is the lower left lower slope 72d in the figure. make contact. That is, the grinding wheel is raised in the thickness direction relative to the workpiece. After that, the glass panel W held by the chuck table 73 is moved in the Y-axis direction at a constant speed, and chamfering is performed for the third round.

Grinding of the central portion (a), grinding of the upper portion (b), and grinding of the lower portion (c) were explained in this order, but without being limited to this, grinding of the upper portion (b), grinding of the central portion (a), The order of grinding (c) of the lower part may be arbitrary. However, grinding the center part (a) first makes it possible to cut out the shape first, and then it is possible to grind the upper part (b) and the lower part (c) more carefully and accurately. Excellent at

In addition, when the work material has a circular portion as shown in FIG. Each grind (c) does not need to go around the circumference of the workpiece. For example, if the circular part is ground only at the upper part (b) and the lower part (c), and the straight part is grinded at the central part (a), the upper part is ground (b) and the lower part is ground (c), respectively. It is possible to improve the surface roughness, shorten the processing time without causing shape collapse, and prevent abrasion, clogging, and deformation of the groove shape.

FIG. 11 shows details of the relationship between the upper surface slope 72u and the lower surface slope 72d of the grinding groove 74 of the outer peripheral precision grinding wheel 72, and explains the relationship between the slope of the grinding groove 74 and the chamfering angle. FIG. 11 shows a state in which the outer peripheral precision grinding wheel 72 is not tilted and is brought into contact with the workpiece W, and the chamfering angle coincides with the angle of the upper slope 72u and the lower slope 72d of the grinding groove 74. FIG.

In order to perform helical grinding, the angle at which the outer peripheral precision grinding wheel 72 is inclined is 3 to 15°, preferably 6 to 10°. The contact area with the upper surface of is not much different from that in FIG. Therefore, as already shown in FIG. 9 , the upper and lower ends (regions of Tu and Td) of the material W to be processed also have streaks in different directions as compared with the central portion C due to the slopes, and the effect of helical grinding is obtained. is sufficiently obtained, and processing distortion and surface roughness are improved to the same extent as in the central portion. The appearance of these three streaks is also a feature of the above embodiment.

In order to make the explanation easier to understand, the slope of the grinding groove 74 may be matched with the chamfering angle by not inclining the outer circumference precision grinding wheel 72 in FIG. 11 . Conversely, the outer peripheral precision grinding wheel 72 may be inclined so that the inclined plane coincides with the chamfering angle of the workpiece W. As shown in FIG. As a result, even if the amount of grinding is small at the start of machining, the contact area between the upper surface slope 72u and the upper surface of the workpiece W increases, and the surface roughness of the upper and lower ends of the workpiece W is improved.

DESCRIPTION OF SYMBOLS 10... Processing part 20... Supply recovery part 30... Wafer cassette 31... Cassette table 40... Supply recovery robot 50... Transfer arm 60... Wafer feeding device 61... Periphery precision grinding device 62... Periphery rough grinding Apparatus 65 Chuck table drive motor 66 Chuck table 67 Peripheral rough grinding motor 68 Peripheral rough grinding spindle (rotating shaft) 69 Peripheral rough grinding wheel 70 Peripheral fine grinding motor 71 Peripheral fine grinding Grinding spindle (rotating shaft) 72 Peripheral precision grinding wheel 72d Lower slope 72u Upper slope 73 Chuck table 74 Grinding groove 80 Surface grinder 81 Precision stage 82 Grindstone 83 ... Workpiece, 84 ... Vise, W ... Wafer, glass panel, Workpiece

Claims (8)

A chamfered substrate manufacturing method for grinding an end face of a plate-shaped workpiece having a corner portion and a straight portion with a grinding groove of a grinding wheel, comprising:
sucking the plane of the workpiece in the thickness direction with a chuck table smaller than the outer peripheral shape of the workpiece;
tilting the axis of rotation of the grinding wheel with respect to the axis in the thickness direction perpendicular to the plane of the workpiece, and pressing the grinding groove against the end surface of the workpiece from the vertical direction to abut;
The upper chamfered portion of the workpiece contacts the upper sloped surface of the grinding groove, and the lower chamfered portion of the workpiece does not contact the lower sloped surface of the ground groove. Grinding on the slope is continuously performed on the entire circumference including the corners of the end face of the workpiece,
After that, the grinding wheel is raised in the thickness direction relative to the workpiece so that the lower chamfered portion of the workpiece contacts the lower sloped surface, and the upper chamfered portion contacts the upper sloped surface. Grinding the chamfered portion of the lower part on the lower sloped surface continuously around the entire circumference including the corners of the end surface of the workpiece,
Alternatively, the lower chamfered portion of the workpiece is ground on the lower sloped surface so that the lower chamfered portion of the workpiece contacts the lower sloped surface and the upper chamfered portion of the workpiece does not contact the upper sloped surface. Continuously perform the entire circumference including the corners of the end face of the work material,
After that, the grinding wheel is lowered relative to the workpiece in the thickness direction so that the upper chamfered portion of the workpiece contacts the upper sloped surface, and the lower chamfered portion contacts the lower sloped surface. Grinding the chamfered portion of the upper portion on the upper sloped surface continuously around the entire circumference including the corners of the end face of the workpiece, so as not to contact the
A method of manufacturing a chamfered substrate , wherein the chuck table is 0.6 to 0.8 times smaller than the outer peripheral shape of the workpiece . A method for manufacturing a chamfered substrate according to claim 1,
A method of manufacturing a chamfered substrate, wherein the width of the grinding groove is made larger than the apparent thickness of the workpiece when the rotation axis of the grinding wheel is tilted. A method for manufacturing a chamfered substrate according to claim 1 or 2,
A method for producing a chamfered substrate, characterized in that the rotation axis of the grinding wheel is inclined by 3 to 15°. A method for manufacturing a chamfered substrate according to claim 1,
A method of manufacturing a chamfered substrate, wherein the processing of the end surface of the workpiece is performed by grinding the upper portion, the center portion, and the lower portion of the end surface of the workpiece, respectively. A chamfering device for chamfering an end face of a plate-shaped workpiece having a corner portion and a straight portion with a grinding groove of a grinding wheel,
a chuck table that adsorbs the plane of the workpiece in the thickness direction and is smaller than the outer peripheral shape of the workpiece;
the grinding wheel that tilts its rotation axis with respect to the axis in the thickness direction that is perpendicular to the plane of the workpiece, and presses the grinding groove against the end surface of the workpiece from the vertical direction to abut it;
with
The upper chamfered portion of the workpiece contacts the upper sloped surface of the grinding groove, and the lower chamfered portion of the workpiece does not contact the lower sloped surface of the ground groove. Grinding on the slope is continuously performed on the entire circumference including the corners of the end face of the workpiece,
After that, the grinding wheel is raised in the thickness direction relative to the workpiece so that the lower chamfered portion of the workpiece contacts the lower sloped surface, and the upper chamfered portion contacts the upper sloped surface. Grinding the chamfered portion of the lower part on the lower sloped surface continuously around the entire circumference including the corners of the end surface of the workpiece,
Alternatively, the lower chamfered portion of the workpiece is ground on the lower sloped surface so that the lower chamfered portion of the workpiece contacts the lower sloped surface and the upper chamfered portion of the workpiece does not contact the upper sloped surface. Continuously perform the entire circumference including the corners of the end face of the work material,
After that, the grinding wheel is lowered relative to the workpiece in the thickness direction so that the upper chamfered portion of the workpiece contacts the upper sloped surface, and the lower chamfered portion contacts the lower sloped surface. Grinding the chamfered portion of the upper portion on the upper sloped surface continuously around the entire circumference including the corners of the end face of the workpiece, so as not to contact the
The chamfering apparatus , wherein the chuck table is 0.6 to 0.8 times smaller than the outer peripheral shape of the workpiece . In the chamfering device according to claim 5,
A chamfering device, wherein the width of the grinding groove is set larger than the apparent thickness of the workpiece when the rotation axis of the grinding wheel is tilted. In the chamfering device according to claim 5 or 6,
A chamfering device, wherein the rotation axis of the grinding wheel is inclined by 3 to 15 degrees. In the chamfering device according to claim 5,
A chamfering apparatus, wherein the end surface of the workpiece is processed by grinding an upper portion, a central portion, and a lower portion of the end surface.

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