JP6789645B2 - Chamfering equipment - Google Patents

Description

The present invention relates to a high-precision chamfering apparatus for end faces of various materials such as silicon, sapphire, compounds, and glass, particularly plate-shaped workpieces such as semiconductor wafers and glass panels, and particularly for plate-shaped workpieces. Suitable for grinding by tilting the grindstone.

In recent years, there has been a strong demand for improving the quality of wafers, and the processing state of the end face (edge portion) of the wafer has been emphasized. In order to prevent chipping due to handling of semiconductor wafers such as silicon wafers used for manufacturing semiconductor devices, etc. A chamfering process is performed by grinding the edge portion, and a mirror chamfering process is performed by polishing. That is, in the semiconductor manufacturing process, quality improvement of edge characteristics is an indispensable process from wafer manufacturing to device manufacturing.

Silicon etc. is hard and brittle, and if the end face of the wafer remains sharp during slicing, it will easily crack or chip during handling such as transportation and alignment in the subsequent processing process, and fragments will damage or contaminate the wafer surface. Or something. To prevent this, the end face of the cut wafer is chamfered with a chamfering grindstone coated with diamond.

In addition, masking printing and sensor electrode formation are performed on a glass substrate that is thinner and lighter for smartphones and tablets, and then cutting is performed to improve chamfering quality, machined surface roughness, and microcracks. It directly affects the end face strength of the glass substrate.

Further, in normal grinding, the chamfered portion is ground in a state where the main surface of the wafer is perpendicular to the rotation axis of the resin grindstone, but in this case, grinding marks in the circumferential direction are likely to occur in the chamfered portion. 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.

In particular, in order to improve the roughness accuracy of the chamfered surface and not reduce the polishing efficiency, in the chamfering method of a semiconductor wafer for polishing the peripheral edge of the semiconductor wafer, the rotation axis of the grindstone is tilted in the tangential direction of the outer periphery of the semiconductor wafer to make a semiconductor. It is known that the direction of abrasive grain movement of a grindstone is tilted with respect to the polished surface of a semiconductor wafer by polishing the peripheral edge of the wafer, which is described in Patent Document 1. In other words, when helical grinding is performed, not only the processing distortion of the chamfered portion is reduced as compared with normal grinding, but also the chamfered portion of the wafer and the grindstone are in surface contact, the contact area is increased, and the surface roughness of the chamfered portion is improved. The effect is obtained.

Further, in the case of chamfering by helical grinding, it is difficult for the coolant to reach the machining point due to the long contact length, and it is difficult to achieve the effects of the coolant such as cooling the wafer and the grindstone and removing and cleaning the grinding debris. Therefore, in order to enable efficient supply of the coolant liquid, the coolant liquid is supplied to the inside of the wafer surface so that the supplied coolant spreads from the inside of the surface to the outer periphery on the wafer surface and reaches the grinding position. It is known to provide a coolant nozzle, which is described in Patent Document 2.

Japanese Unexamined Patent Publication No. 5-152259 JP-A-2007-48780

In the above-mentioned conventional technique, the surface roughness is improved by helical grinding, but the contact area is increased and the resistance to the wafer is increased. For example, if the rotation axis of the grindstone is tilted downward, the surface roughness is improved by that amount. Due to the force, the wafer may be bent and deformed from the center to the tip during chamfering, that is, the tip may sag. Then, the bending deformation affects the shape accuracy of the machined surface, which is an obstacle in performing more accurate machining.

Further, even if the coolant liquid is simply supplied as described in Patent Document 2, the surface roughness is deteriorated due to the impaired inflow and retention of the coolant liquid due to the rotation of the grindstone and the poor discharge of chips. There was a risk of shortening the life of the grindstone as well as deteriorating it.

An object of the present invention is to solve the above-mentioned problems of the prior art, eliminate bending deformation of the work material caused during chamfering by helical grinding, improve processing accuracy, and inflow and retention of coolant and discharge of chips. The purpose is to improve the surface roughness and the deterioration of the grindstone.

In order to achieve the above object, the present invention is a chamfering apparatus for grinding the end face of a plate-shaped work material (wafer) with respect to a axis in the thickness direction perpendicular to the plane of the work material. Is tilted and pressed against the end face of the work material from the vertical direction to come into contact with the upper grinding grind (upper outer peripheral fine grinding grind), and the upper grinding grind is arranged below the upper grinding grind so as to have a gap in the direction of the rotation axis. A lower grinding grind (lower outer peripheral fine grinding grind) whose rotation direction is opposite to that of the upper grinding grind is provided, and the end face of the work piece is ground by the upper grinding grind and the lower grinding grind. ..

Further, in the above, it is desirable that the upper grinding wheel and the lower grinding wheel are arranged so that the rotation axes are concentric.

Further, in the above, it is desirable that the upper grinding wheel and the lower grinding wheel form a grinding groove for processing the work material, and the gap is smaller than the thickness of the work material.

Further, in the above, it is desirable that the gap is provided at the center of the grinding groove in the rotation axis direction.

Further, in the above, it is desirable that the gap is 0.1 to 1 mm.

Further, in the above, it is desirable that the rotation axis of the upper grinding wheel and the lower grinding wheel is tilted by 3 to 15 ° in the tangential direction of the outer periphery of the work piece.

Further, in the above, the upper grinding wheel is rotated counterclockwise, the lower grinding wheel is rotated clockwise, the coolant liquid to the upper grinding wheel is from the upper side of the work piece, and the coolant liquid to the lower grinding wheel is It is desirable to supply from the lower side of the work material.

Further, in the above, it is desirable that the coolant liquid flows in along the rotation direction of the upper grinding wheel and the lower grinding wheel.

Further, in the above, it is desirable that the upper grinding wheel and the lower grinding wheel are reversely rotated and trued.

According to the present invention, the upper grinding wheel (upper outer peripheral grinding wheel) that tilts the rotation axis with respect to the axis in the thickness direction and presses against the end face of the work piece from the vertical direction to abut, and below the upper grinding wheel. Since it is provided with a lower grinding wheel (lower outer peripheral fine grinding wheel) that is arranged so as to have a gap in the direction of the rotation axis and whose rotation direction is opposite to that of the upper grinding wheel, bending deformation of the work material that occurs during machining Can be eliminated and the processing accuracy can be improved.

Front view showing the main part of the chamfering apparatus according to the embodiment of the present invention. Enlarged side view of a part of the outer peripheral Seiken spindle portion in one embodiment Top view showing the main part of the whole in one embodiment Top view showing the structure of the machined part in one Embodiment Side view showing the state during processing of the outer peripheral refined spindle portion in one embodiment. Top view explaining the coolant nozzle in one Embodiment Cross-sectional view showing the shape of the wafer W after processing by the prior art Sectional drawing which shows the shape of the wafer W after processing in one Embodiment Side view showing a trueing operation in one embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing a main part of a chamfering device according to an embodiment of the present invention. The chamfering device 10 includes a wafer feed unit 20, a grindstone rotating unit 50, a wafer supply / storage unit (not shown), a wafer cleaning / drying unit, a wafer transfer means, a controller for controlling the operation of each unit of the chamfering device, and the like.

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

The X table 24 is moved in the Y direction in the figure by a Y-axis drive mechanism including two Y-axis guide rails 26, 26, four Y-axis linear guides 27, 27, ..., A ball screw and a stepping motor (not shown). The Y table 28 to be used is incorporated.

The Y table 28 is guided by two Z-axis guide rails 29, 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 including a ball screw and a stepping motor. Z table 31 is incorporated.

A θ-axis motor 32 and a θ-spindle 33 are incorporated in the Z-table 31, and a wafer table 34 on which a wafer W (plate-shaped workpiece) is sucked and placed is attached to the θ-spindle 33. Is rotated in the θ direction in the figure about the wafer table rotation axis CW.

Further, at the lower part of the wafer table 34, a truing grindstone 41 (hereinafter referred to as a truer 41) used for truing the grindstone for finishing chamfering the peripheral edge of the wafer W is attached concentrically with the wafer table rotation axis CW.

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

The grindstone rotation unit 50 has an outer peripheral grindstone spindle 51 to which an outer peripheral rough grinding grindstone 52 is attached and is rotationally driven around an axis by an outer peripheral grindstone motor (not shown), and an upper outer peripheral precision wheel attached to a turntable 53 arranged above. It has a grinding spindle 54 and an upper peripheral grinding motor 56. Similarly, the turntable 53 is provided with a lower outer circumference refined spindle 57 and a lower outer circumference refined motor (not shown) via a lower fixed frame 59 (not shown in FIG. 1).

The upper outer peripheral fine research spindle 54 and the lower outer peripheral fine research spindle 57 are finished by chamfering the outer circumference of the wafer W in a state where the rotation axis is tilted by 3 to 15 °, preferably 6 to 10 ° with respect to the rotation axis of the wafer W. I do. As a result, helical grinding is performed, and although weak grinding marks are generated in the chamfered portion of the wafer W in the oblique direction, the effect of improving the surface roughness of the chamfered portion can be obtained as compared with normal grinding.

FIG. 2 is an enlarged side view of a part of the outer peripheral fine grinding wheel portion, and the upper outer peripheral fine grinding wheel 54 is a chamfering grindstone for finishing and grinding the outer periphery of the wafer W. ) 55-1 is attached, and similarly, the lower outer peripheral grinding wheel (lower grinding wheel) 55-2 is smaller than the thickness of the wafer W with respect to the upper outer peripheral grinding wheel 55-1 on the lower outer peripheral grinding wheel 57. It is installed so that the rotating shafts are substantially concentric with a gap of about 0.1 to 1 mm.

Further, the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 are driven by the upper outer peripheral fine grinding spindle 54 and the lower outer peripheral fine grinding spindle 57 so that the rotation directions are opposite, that is, opposite rotations. Will be done. The grinding groove for processing the wafer W is formed by the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2. The gap is provided substantially at the center of the grinding groove in the direction of rotation axis.

The wafer processing process is performed in the order of slicing → chamfering → wrapping → etching → donor killer → fine chamfering, and various cleanings are used to remove stains between the processes. Silicon etc. is hard and brittle, and if the end face of the wafer remains sharp during slicing, it will easily crack or chip during handling such as transportation and alignment in the subsequent processing process, and fragments will damage or contaminate the wafer surface. Or something. In order to prevent this, in the chamfering process, the end face of the cut wafer is chamfered with a chamfering grindstone coated with diamond.

The chamfering step may be performed after the wrapping step. At this time, it is also included to match the diameters of the outer circumferences with variations, to match the width of the orientation flat (OF), and to match the dimensions of a minute notch called a notch.

FIG. 3 is a plan view showing a main part of the entire chamfering device 10, and the supply / recovery unit supplies the chamfered wafer W from the wafer cassette 70 and collects the chamfered wafer into the wafer cassette 70. This operation is performed by the supply / recovery robot 40. The wafer cassette 70 is set on the cassette table 71, and a large number of wafers to be chamfered are stored. The supply / recovery robot 40 takes out wafers W one by one from the wafer cassette 70, and stores chamfered wafers in the wafer cassette 70.

The supply / recovery robot 40 is provided with a 3-axis rotary type transfer arm 80, and the transfer arm 80 is provided with a suction pad (not shown) on the upper surface thereof. The transfer arm 80 holds the wafer W by vacuum suctioning the back surface of the wafer with a suction pad. That is, the transfer arm 80 of the supply / recovery robot 40 can move back and forth, move up and down, and turn while holding the wafer W, and transfers the wafer by combining these operations.

The chamfering device 10 is arranged on the front surface portion, and performs all the chamfering of the outer peripheral surface of the wafer W, that is, from roughing to finishing. The chamfering device 10 is composed of a wafer feed unit 20 and a grindstone rotation unit 50.

FIG. 4 is a plan view showing the configuration of the processed portion. In the standby state before the start of processing, the wafer W held on the wafer table 34 is arranged so that the center thereof coincides with the rotation axis of the wafer table 34. To. At this time, the OF portion of the wafer W is arranged so as to face a predetermined direction.

Further, the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 constituting the outer peripheral rough grinding wheel 52 and the outer peripheral grinding wheel 55 are located at positions separated from the wafer W by predetermined distances, respectively. Specifically, the rotation center of the outer peripheral rough grinding wheel 52 is arranged at a position separated by a predetermined distance in the Y-axis direction from the rotation center of the wafer W, and the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-1 are finely ground. The center of rotation of the grindstone 55-2 is arranged at a position separated by a predetermined distance in the X-axis direction with respect to the wafer W.

First of all, an alignment operation is performed. In this alignment operation, the relative positional relationship between the wafer W held on the wafer table 34 and the outer peripheral rough grinding wheel 52 and the outer peripheral fine grinding wheel 55 is adjusted in the vertical direction (Z-axis direction).

When the alignment operation is completed, the outer peripheral grindstone spindle 51 is driven. Next, grinding (roughing) with the outer peripheral rough grinding wheel 52 is started. Specifically, a Y-axis motor (not shown) of the outer peripheral rough grinding apparatus 62 is driven, and the outer peripheral grindstone spindle 51 is fed toward the wafer table 34 along the Y-axis direction.

The outer peripheral rough grinding wheel 52 is a metal bond grindstone having diamond abrasive grains having a diameter of 200 mm and has a particle size of # 800. Further, the outer peripheral grindstone spindle 51 is a spindle driven by a built-in motor using ball bearings, and is rotated at a rotation speed of 8,000 rpm.

When the outer peripheral grindstone spindle 51 is sent toward the wafer table 34, the outer periphery of the wafer W comes into contact with the grinding groove for outer peripheral rough grinding formed on the outer peripheral rough grinding wheel 52, and the outer peripheral portion of the wafer W becomes the outer peripheral rough grinding wheel. Grinding by 52, roughing of the outer peripheral chamfer of the wafer W is started.

After the roughing by the outer peripheral rough grinding wheel 52 is started, the wafer W held on the wafer table 34 starts rotating in the arrow direction at a constant speed. When this rotation angle, that is, the OF portion where the machining point is a straight line portion is reached, the feed amount of the outer peripheral grindstone spindle 51 toward the Y direction and the wafer table 34 is increased, and the outer peripheral grindstone spindle 51 is linearly moved in the X direction to make a straight line. Process the part. After that, when the machining of the straight portion is completed, the plate-shaped wafer W held on the wafer table 34 is rotated again in the direction of the arrow at a constant speed, the remaining circular portion is ground, and the rough machining by the outer peripheral rough grinding wheel 52 is performed. To finish.

Next, the finishing process is similarly performed by the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2, which are the outer peripheral grinding wheels 55. As the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2, a resin bond grindstone with diamond abrasive grains is suitable. Further, the upper outer peripheral refined spindle 54 and the lower outer peripheral refined spindle 57 are concentric, and the rotation axis thereof is 3 to 15 ° in the tangential direction of the outer periphery of the wafer W with respect to the rotation axis of the wafer table 34, preferably. The finishing process of chamfering the outer periphery of the wafer W is performed in a state of being inclined at 6 to 10 °, that is, in a direction perpendicular to the surface of the wafer W.

Further, the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 are formed as a set, and the chamfering groove is formed by the truer 41. The upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 are made of the same material, and are formed by mixing, for example, metal powders such as Fe, Cr, and Cu as main components and diamond abrasive grains. Is used. As the material, for example, it is desirable that the main component is phenol resin, epoxy resin, polyimide resin, polystyrene resin, polyethylene resin or the like, and the material is formed by mixing diamond abrasive grains or cubic boron nitride abrasive grains.

Further, the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 are resin bond grindstones having diamond abrasive grains having a diameter of 50 mm, and the particle size # 3000 is used. The upper outer circumference Seiken spindle 54 and the lower outer circumference Seiken spindle 57 are built-in motor-driven spindles using air bearings, and are rotated at a rotation speed of 35,000 rpm.

The material of the truer 41 is a material that can be processed by the outer peripheral coarse grinding wheel 52, while the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 can be ground. For example, it is desirable that abrasive grains made of silicon carbide are bonded with a phenol resin by adding a filler or the like as necessary, and this is formed into a disk-shaped turret 41. Further, the tooler 41 has an outer diameter equal to or smaller than that of the wafer W to be processed, and may be a disk-shaped GC (Green carbide) grindstone or a WA (White fused aluminum) grindstone having the same thickness, and the grain size of the grindstone is # 320. The degree is good.

Further, in the grinding wheel, a lubricant is supplied together with a saturated fatty acid solution to a chamfering wheel material having a porous surface, and the surface is dried to obtain a lubricant-impregnated grindstone, and the grindstone containing this lubricant is used for water cooling at the time of grinding. Is desirable.

FIG. 5 is a side view showing a state in which the outer peripheral fine research spindle portion is being machined, and shows the rotation direction and force of the upper outer peripheral fine research spindle 54 and the lower outer peripheral fine research spindle 57, the inflow and retention of coolant, and the discharge of chips. Shows the relationship. The upper outer circumference Seiken spindle 54 rotates counterclockwise (rotates from left to right in the direction drawing indicated by arrow A), tilts clockwise with respect to the rotation axis of the wafer W, and tilts downward from left to right in the figure. Therefore, a force is applied to the wafer W as shown by the arrow A. Since the center of the wafer W is held and the outer circumference is a free end, the wafer W can be bent downward by a component force. On the other hand, the lower outer peripheral Seiken spindle 57 is rotated clockwise (rotated from right to left in the direction drawing indicated by arrow B) and is inclined upward from right to left in the drawing, so that it is as shown by arrow B with respect to the wafer W. Power is applied to.

Since the gap between the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 is symmetrical in the center in the direction of the rotation axis, the wafer W and the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding are finely ground. The contact area with the grindstone 55-2 is equal. Therefore, the respective grinding resistors are balanced and do not generate a force that bends the wafer W. As a result, the wafer W is not bent and deformed from the center to the tip, and the shape accuracy of the machined surface due to the bending deformation is not affected.

Arrows C and D indicate the inflow direction of the coolant liquid, and the upper side of the wafer W is centered from the outer periphery of the wafer W from the left side in FIG. 5 along the rotation direction and the counterclockwise direction of the upper outer peripheral grinding wheel 55-1. Inflow toward. The lower side flows from the right side toward the center from the outer circumference of the wafer W along the rotation direction and the clockwise direction of the lower outer circumference fine grinding wheel 55-2.

FIG. 6 is a plan view illustrating a coolant nozzle when chamfering the outer periphery of the wafer W with the outer peripheral fine grinding wheel 55, and is an example in which coolant nozzles 71A and 71B are provided in the vicinity of the wafer table 34 (FIG. 1). is there. The coolant nozzle 71A supplies the coolant liquid 91A to the inside of the upper surface of the wafer W. The supplied coolant 91A reaches the grinding point by the injection force and the centrifugal force due to the rotation of the upper peripheral fine grinding wheel 55-1. Further, the coolant nozzle 71B supplies a coolant liquid (not shown) to the inside of the lower surface of the wafer W. The supplied coolant reaches the grinding point by the jetting force and the centrifugal force due to the rotation of the lower peripheral grinding wheel 55-2.

In FIG. 6, the injection ports of the coolant nozzles 71A and 71B are brought closer to the grinding point, but since the rotation directions of the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 are opposite, grinding is not necessarily performed. You don't have to get close to the point. The coolant liquid flowing in from both sides is accelerated as the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 rotate, but collides with each other at a processing point near the center of the wafer W. The inflow speed is weakened. Therefore, the coolant liquid stays at the processing point, sufficiently cools the wafer W, the upper outer peripheral grinding wheel 55-1, and the lower outer peripheral grinding wheel 55-2, and flows out from the gap. Further, the grinding debris associated with grinding is discharged and removed from the gap as the coolant flows in and out, and the effect of the coolant liquid can be promoted to enhance the effect of helical grinding and improve the processing quality.

As described above, the lubricant can be reliably supplied to the cutting point of the grindstone and the cutting point temperature can be set to a predetermined temperature or lower. Further, if the coolant is water, environmental pollution due to the coolant can be prevented. Further, in the wafer chamfering apparatus, if the grindstone is impregnated with a lubricant, the lubricant can be supplied to the cutting point for a long period of time, and moreover, low temperature and environment-friendly processing can be performed by using the coolant as water. Further, since the grinding debris is discharged from the gap, it does not fall on the machined surface, and scratches due to grinding debris or the like and streaks due to scratches are not generated on the machined surface.

Further, the size of the wafer table 34 for fixing the wafer W must be determined in consideration of fixing and grinding resistance, but the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 are rotated in the reverse direction. By doing so, the influence on the processing accuracy such as deformation, bending, and distortion of the wafer W is avoided, and the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 are made into soft resin bond grindstones. The impact such as the runout can be alleviated.

Further, usually, if the inclination angle of the outer peripheral grinding wheel 55 is too large, it is not preferable in terms of an increase in grinding resistance, chipping of upper and lower corners on the end face, scratches, etc., but the upper outer peripheral grinding wheel 55-1 and the lower outer circumference are not preferable. It is also advantageous in this respect that the rotation of the fine grinding wheel 55-2 is reversed.

The rotation axes of the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 are substantially concentric, but they do not necessarily have to be exactly concentric, and the number of rotations, wafer W, and grinding It may be appropriately shifted depending on the processing conditions such as the material of the grindstone and the angle of inclination for helical grinding. Similarly, it is not necessary to match each rotation speed exactly, and one of the rotation speeds can be made smaller depending on the processing conditions such as the finished state, accuracy, coolant inflow state, and tilted angle for helical grinding. You may.

FIG. 7 is a cross-sectional view showing the shape of the wafer W after processing by the conventional technique, showing the shape of the wafer W at the cutting position processed by the normal outer peripheral grinding wheel 55, and has a thickness of 740 μm and an upper surface A1. The symmetry of the chamfered portion was broken by bending the wafer W downward so that the lower surface A2 was 250 μm, B2 was 190 μm, and θ2 was 40 ° with respect to 340 μm, B1 was 300 μm, and θ1 was 43 °. ..

FIG. 8 is a cross-sectional view showing the shape of the wafer W after processing in one embodiment. With respect to FIG. 7, the outer peripheral grinding wheel 55 is separated into upper and lower parts, and the upper outer peripheral grinding wheel 55-1 and the lower outer circumference are separated. The shape of the wafer W when the fine grinding wheel 55-2 is rotated in the reverse direction is shown. The symmetry of the chamfered portion is improved so that the thickness is 740 μm and the upper surface A1 is 290 μm and B1 is 260 μm and θ1 is 44 °, while the lower surface A2 is 290 μm and B2 is 240 μm and θ2 is 42 °. The accuracy is improved.

FIG. 9 is a side view showing the truing operation, which is attached to the lower part of the wafer table 34 concentrically with the center of rotation of the wafer table and rotated by the wafer table 34. In the truing operation, first, a master grindstone (not shown) is used to chamfer the outer circumference of the truer 41. In this processing, the master grindstone is rotated at a rotation speed of 8,000 rpm. In this state, the Z table 31 is moved by the Z-axis drive mechanism 30, and the height of the tooler 41 is positioned so as to match the master groove of the master grindstone.

The outer peripheral portion of the turret 41 is chamfered, and the shape of the master groove is transferred to the outer peripheral portion of the turret 41. The transfer from the cross-sectional shape of the master groove of the master grindstone to the cross-sectional shape of the outer peripheral portion of the truer 41 is completed. Using the truer 41 in which the cross-sectional shape of the master groove is transferred to the outer peripheral portion, the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2 whose rotation axis is inclined in the tangential direction of the wafer W are formed. The grinding groove formed in the outer peripheral fine grinding wheel 55 is equivalent to that formed by a trueing grindstone having an outer diameter equivalent to the outer diameter D of the wafer W.

Since the upper outer peripheral grinding wheel 55-1 and the lower outer peripheral grinding wheel 55-2 are rotated in the reverse direction in the tsuruing operation, the grinding debris is not affected by the shape accuracy of the machined surface due to bending deformation as in the case of outer peripheral grinding. Is also discharged from the gap, so more accurate shape transfer is performed.

W ... Wafer, glass panel (work material), 10 ... Chamfering device, 11 ... Main body base, 20 ... Wafer feed unit, 21 ... X-axis base, 22 ... X-axis guide rail, 23 ... X-axis linear guide, 24 ... X table, 25 ... X-axis drive mechanism, 26 ... Y-axis guide rail, 27 ... Y-axis linear guide, 28 ... Y table, 29 ... Z-axis guide rail, 30 ... Z-axis drive mechanism, 31 ... Z table, 32 ... θ-axis motor, 33 ... θ spindle, 34 ... Wafer table, 40 ... Supply and recovery robot, 41 ... Turer, 50 ... Grinding unit, 51 ... Outer peripheral grinding spindle, 52 ... Outer peripheral grinding grind, 53 ... Turntable, 54 ... Upper outer circumference fine grinding spindle, 55 ... outer peripheral fine grinding grind, 55-1 ... upper outer peripheral fine grinding grind (upper grinding grind), 55-2 ... lower outer peripheral fine grinding grind (lower grinding grind), 56 ... upper outer peripheral fine grinding motor , 57 ... Lower outer circumference fine grinding spindle, 59 ... Lower fixed frame, 62 ... Outer circumference rough grinding device, 70 ... Wafer cassette, 71 ... Cassette table, 71A, 71B ... Coolant nozzle, 80 ... Conveying arm, 91A ... Coolant liquid

Claims (7)

In a chamfering machine that helically grinds the end face of a plate-shaped work piece
An upper outer circumference fine grinding spindle equipped with an upper grinding wheel that grinds the outer circumference of the work material,
Similarly, a lower outer circumference fine grinding spindle in which the lower grinding wheel is attached to the upper grinding wheel so that the rotation axes are substantially concentric with a gap smaller than the thickness of the work piece.
A grinding groove formed by the upper grinding wheel and the lower grinding wheel,
The upper outer peripheral refined spindle and the lower outer peripheral refined spindle in which the rotation axis is inclined in the tangential direction of the outer periphery of the workpiece with respect to the direction perpendicular to the main surface of the workpiece.
The upper grinding wheel and the lower grinding wheel are driven by the upper outer peripheral fine grinding spindle and the lower outer peripheral fine grinding spindle so that the rotation directions are opposite to each other, and the grinding groove of the work material. A chamfering device characterized in that the outer circumference is machined. The chamfering apparatus according to claim 1, wherein the gap is provided at the center of the grinding groove in the direction of the rotation axis. The chamfering apparatus according to claim 1 or 2, wherein the gap is 0.1 to 1 mm. The chamfering apparatus according to any one of claims 1 to 3, wherein the rotating shaft is inclined by 3 to 15 ° in a tangential direction of the outer circumference of the material to be processed. The upper grinding wheel is rotated counterclockwise, the lower grinding wheel is rotated clockwise, the coolant liquid to the upper grinding wheel is from the upper side of the work material, and the coolant liquid to the lower grinding wheel is the lower side of the work material. The chamfering apparatus according to any one of claims 1 to 4, wherein the chamfering apparatus is supplied from. The chamfering apparatus according to claim 5 , wherein the coolant liquid flows in along the rotation direction of the upper grinding wheel and the lower grinding wheel. The chamfering apparatus according to any one of claims 1 to 6, wherein the upper grinding wheel and the lower grinding wheel are rotated in the reverse direction and trued.