JP2018167331A - Truing method and chamfer device - Google Patents

Abstract

To improve a transfer rate and the processability of truing, and to improve the accuracy of a groove formed at a truer.SOLUTION: In a truing method for forming a groove of a grinding stone 55 for grinding a chamfer part of a wafer W by using a disc-shaped truer 41, a plane surface of the truer 41 which is thinned in a thickness more than a width of the groove is fixed in the thickness direction by a table 34 which is smaller than an external peripheral shape of the truer 41, an upper part or a lower part in a scheduled position of the groove in which the truer 41 is formed at the grinding stone 55 is processed by the truer 41, and after that, the truer 41 is processed by being relatively descended or ascended to the thickness direction with respect to the grinding stone 55.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a high-precision chamfering device at the end face of various materials such as silicon, sapphire, compound, glass, particularly a plate-like workpiece such as a semiconductor wafer, a glass panel, etc., and particularly a grindstone for the plate-like workpiece. It is suitable for a truing method and a chamfering device for forming a processing groove of a grindstone used for helical grinding.

  Silicon and other materials are hard and brittle, and if the edge of the wafer remains sharp during slicing, it can easily crack or chip during handling such as transport and alignment in subsequent processing steps, and fragments can damage or contaminate the wafer surface. Or In order to prevent this, the end surface of the cut wafer is chamfered with a chamfering grindstone coated with diamond.

  In addition, masking printing is performed on thin and lightweight glass substrates of smartphones and tablets, sensor electrodes are formed, and then cut, and chamfering processing quality, processing surface roughness, microcracking, etc. are made of glass. It directly affects the edge strength of the 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. In this case, circumferential grinding marks are likely to occur in the chamfered portion. Therefore, it is known to perform so-called helical grinding in which a chamfered portion of a wafer is ground by tilting a resin bond grindstone (resin grindstone) with respect to the wafer, for example.

  In addition, in truing that forms the groove for grinding the chamfered portion of the wafer by transferring the groove shape of the grindstone through the truer, warpage and undulation of the truer are likely to occur, and the accuracy of the formed groove and the truing time The truing efficiency is significantly reduced.

  When helical grinding is performed, if a groove is formed or modified (truing) using a truer whose edges are formed symmetrically on the resin grindstone, the resin grindstone is tilted, so the twister is twisted. Therefore, the groove of the resin grindstone is processed into an asymmetric shape in the vertical direction. Therefore, it is known to form the groove shape by forming the edge portion of the truer into a vertically asymmetric groove shape, and grinding the grindstone by relatively tilting the truer and the grindstone.

JP 2007-165712 A

  In the above prior art, when a groove is formed using a truer or when truing, the grindstone groove may be chamfered into a vertically symmetrical shape, but the load in the vertical direction of the truer may be There is no change in the deformation of the truer in the direction of rotation. For this reason, the transfer rate is poor, affecting the accuracy of the grooves formed, the truing time, etc., and the truing efficiency is significantly reduced. In addition, since the contact area between the truer and the grindstone is widened, the discharging performance of coolant and the inflow of coolant are impaired.

  An object of the present invention is to solve the above-mentioned problems of the prior art, improve the truing transfer rate and processability, and improve the accuracy of grooves formed by the truer. In particular, regarding the accuracy of the groove, not only the dimensional accuracy but also the groove angle and the corner of the end are not rounded to improve the shape accuracy and improve the accuracy of the final chamfered shape. is there.

  In order to achieve the above object, the present invention is a truing method in which a groove of a grindstone for grinding a chamfered portion of a wafer (peripheral precision grinding grindstone 55) is formed by a disk-shaped truer, and the thickness is larger than the width of the groove. The planar surface of the reduced truer is fixed in the thickness direction with a table (wafer table 34) smaller than the outer peripheral shape of the truer, and the upper or lower part of the groove where the truer is formed in the grindstone is formed at the upper or lower part of the groove. Then, the truer is lowered or raised in the thickness direction relative to the grindstone.

  In the above, it is desirable that the rotation axis of the grindstone is inclined with respect to the axis in the thickness direction perpendicular to the plane of the truer.

  Further, in the above, the upper portion at the predetermined position of the groove for forming the truer on the grindstone is processed by the truer, and then the truer is lowered relative to the grindstone in the thickness direction so as to form the groove. It is desirable to machine to the lower part of the planned position.

  Further, in the above, a central portion at a predetermined position of the groove that forms the truer on the grindstone is processed by the truer, and then the truer is raised or lowered relative to the grindstone in the thickness direction. It is desirable to process.

  Furthermore, in the above, it is desirable to process the truer while swinging it relative to the grindstone in the thickness direction.

  Furthermore, in the above, it is desirable that the rotation axis of the grindstone is inclined by 3 to 15 ° with respect to the axis in the thickness direction perpendicular to the plane of the truer.

  Furthermore, in the above, it is desirable that the thickness of the truer is 20-30% smaller than the width of the groove.

  The present invention also relates to a chamfering apparatus for chamfering an end face of a plate-like workpiece with a grindstone groove, a disk-shaped truer whose thickness is smaller than the width of the groove, and a flat surface of the truer. A table that is smaller than the outer peripheral shape of the truer that is fixed in the direction, and the upper or lower part of the groove where the truer is formed in the grindstone is processed by the truer, and the truer is then processed by the truer. Processing is performed by lowering or raising in the thickness direction relative to the grindstone.

  Furthermore, in the above, it is desirable that the rotation axis of the grindstone is inclined with respect to the axis in the thickness direction perpendicular to the plane of the truer.

  Further, in the above, the grindstone is attached so that the upper grinding wheel and the lower grinding grind have a gap and the rotation shaft is substantially concentric, and the groove is the upper grinding grindstone and the lower grinding grindstone. It is desirable to form with a grinding wheel.

  According to the present invention, an upper portion or a lower portion at a predetermined position of the groove is processed with a truer whose thickness is smaller than the width of the groove of the grindstone for grinding the chamfered portion of the wafer. Since the processing is performed by lowering or raising in the thickness direction, the transfer rate and processability of truing can be improved, and the accuracy of the grooves formed in the truer can be improved. Therefore, a chamfering device with improved chamfering shape accuracy can be obtained.

The front view which shows the principal part of the chamfering apparatus which concerns on one Embodiment of this invention. The top view which shows the principal part of the chamfering apparatus in one Embodiment. The top view which shows the structure of the process part in one Embodiment. The side view which shows the state in process of the wafer W in one Embodiment Side view showing truing process in one embodiment Explanatory drawing which shows the processing method by one Embodiment Explanatory drawing which shows the processing method by one Embodiment Explanatory drawing showing the force applied to the truer during truing processing Explanatory drawing showing the range of contact between the truer and the grindstone during truing processing

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

  In the chamfering apparatus, the wafer W is transported to the processing unit by the supply / recovery robot 40 from the state in which the wafer W is put in the wafer cassette 70 and is recovered (see FIG. 2). 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 so-called helical grinding is performed in which the chamfered portion of the wafer is ground by tilting the resin grindstone.

  In FIG. 1, a wafer feed unit 20 includes an X-axis base 21, two X-axis guide rails 22, 22, four X-axis linear guides 23, 23,. And an X table 24 which is moved in the X direction in the figure by an X-axis drive mechanism 25 comprising a stepping motor.

  The X table 24 has two Y-axis guide rails 26, 26, four Y-axis linear guides 27, 27,..., And is moved in the Y direction in the figure by a Y-axis drive mechanism including 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 and 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 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-like workpiece) is sucked and mounted is attached to the θ spindle 33. The table is rotated around the table rotation axis CW in the θ direction in the figure.

  A truing grindstone 41 (hereinafter referred to as a truer 41) used for truing a grindstone for chamfering the peripheral edge of the wafer W is fixed to the lower portion of the wafer table 34 so as to be concentric with the wafer table rotation axis CW. ing. As a material of the truer 41, for example, it is desirable that abrasive grains made of silicon carbide, for example, be added with a filler or the like and bonded with a phenol resin, and then formed into a disk-like truer 41.

  The wafer feed unit 20 allows the wafer W and the truer 41 to rotate in the θ direction in the figure and to move in the X, Y, and Z directions. The grindstone rotating unit 50 is provided with an outer peripheral rough grinding grindstone 52, an outer grindstone spindle 51 which is driven to rotate around an axis by an unillustrated outer grindstone motor, and an upper outer perimeter precision mounted on an upper turntable 53. A grinding spindle 54 and an upper and outer peripheral fine grinding motor 56 are provided. Similarly, a lower outer peripheral precision spindle 57 and a lower outer peripheral precision motor (not shown) are provided on the turntable 53 via a lower fixing frame 59 (not shown in FIG. 1).

  The upper and lower outer peripheral spindles 54 and 57 are finished by chamfering the outer periphery of the wafer W with the rotation axis inclined by 3 to 15 °, preferably 6 to 10 ° with respect to the rotation axis of the wafer W. I do. Thereby, although helical grinding is performed and a weak grinding trace is generated in the chamfered portion of the wafer W in an oblique direction, an effect of improving the surface roughness of the chamfered portion as compared with normal grinding can be obtained.

  The upper outer periphery precision grinding spindle 54 is equipped with an upper outer periphery precision grinding wheel (upper grinding wheel) that is a chamfering grind for grinding the outer periphery of the wafer W. Similarly, the lower outer periphery precision grinding spindle 57 is provided with a lower outer periphery precision grinding. The grindstone (lower grinding grindstone) is attached to the upper and outer peripheral fine grinding grindstones so that the rotating shaft is substantially concentric with a gap of about 0.1 to 1 mm smaller than the thickness of the wafer W.

  Further, the upper outer periphery precision grinding wheel and the lower outer periphery precision grinding wheel are driven by the upper outer periphery precision grinding spindle 54 and the lower outer periphery precision grinding spindle 57, respectively, so that the rotation directions are reverse, that is, reverse rotation. A grinding groove for processing the wafer W is formed by an upper and outer peripheral precision grinding wheel and a lower and outer peripheral precision grinding wheel.

  The wafer processing process is performed in the order of block cutting → orientation flat (OF) processing → slicing → chamfering → lapping → etching → donor killer → fine chamfering, and various cleanings are used to remove dirt between the processes. In block cutting, both ends (top and tail) of the ingot are cut and the outer periphery is ground, and the long one is cut at an appropriate length to form a cylindrical “block” having a predetermined diameter.

  In orientation flat (OF) processing, the crystal orientation is measured, and an orientation flat (OF) or “notch” is cut into a predetermined position so that the orientation can be determined in a later step. In slicing, a wafer is cut out from the block with a dicing saw, a wire saw, or an inner peripheral blade. A block having a diameter of 300 mm is usually cut up to 200 at a time by a multi-wire saw.

  In the chamfering, if the end surface of the wafer remains sharp during slicing, the wafer is easily cracked or chipped during handling such as conveyance and alignment in subsequent processing steps, and the fragments damage or contaminate the wafer surface. In order to prevent this, the end face of the cut wafer is chamfered with a grinding wheel coated with diamond.

  The chamfering process may be performed after the lapping process. At this time, the diameter of the outer periphery with variations is matched, the length of the width of the orientation flat (OF) is matched, and the dimension of a small notch called a notch is also matched.

  FIG. 2 is a plan view showing the main part of the entire chamfering apparatus 10. The supply / recovery unit supplies the wafer W to be chamfered from the wafer cassette 70 and collects the chamfered wafer in the wafer cassette 70. This operation is performed by the supply / recovery robot 40. The wafer cassette 70 is set on a cassette table 71 and contains a number of wafers W to be chamfered. The supply / recovery robot 40 takes out the wafers W one by one from the wafer cassette 70 and stores the chamfered wafers W in the wafer cassette 70.

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

  The chamfering device 10 is disposed in the front portion, and performs all processes for chamfering the outer periphery of the wafer W, that is, from roughing to finishing. The chamfering apparatus 10 includes a wafer feeding unit 20 and a grindstone rotating unit 50.

  FIG. 3 is a plan view showing the configuration of the processing unit. 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. The At this time, the OF portion of the wafer W is arranged to face a predetermined direction.

  Further, the outer peripheral rough grinding wheel 52 and the outer peripheral fine grinding wheel 55 are located at a predetermined distance from the wafer W, respectively. Specifically, the rotation center of the outer peripheral rough grinding wheel 52 is disposed at a position separated from the rotation center of the wafer W by a predetermined distance in the Y-axis direction, and the rotation center is in the X-axis direction with respect to the wafer W. It is arranged at a position separated by a predetermined distance.

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

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

  When the outer peripheral grinding wheel spindle 51 is fed toward the wafer table 34, the outer periphery of the wafer W comes into contact with the outer peripheral rough grinding grinding groove formed in the outer peripheral rough grinding wheel 52, and the outer periphery of the wafer W is the outer peripheral rough grinding wheel. After being ground by 52, rough machining of the outer peripheral chamfering of the wafer W is started.

  After the rough machining by the outer peripheral rough grinding wheel 52 is started, the wafer W held on the wafer table 34 starts to rotate in the arrow direction at a constant speed. When the rotation angle, that is, the OF portion where the processing point is a linear portion, the outer grindstone spindle 51 is increased in the Y direction and the feed amount toward the wafer table 34 is increased, and the outer grindstone spindle 51 is linearly moved in the X direction to obtain a straight line. Machining part. Thereafter, when the processing of the straight portion is finished, the plate-like 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 rough processing by the outer peripheral rough grinding wheel 52 is performed. Exit.

  Next, the finishing process by the outer peripheral grinding wheel 55 is performed in the same manner. Further, the outer peripheral fine grinding wheel 55 has chamfering grooves formed by the truer 41.

  Finishing is performed in the same manner by the upper and outer peripheral fine grinding wheels 55-1 and 55-2 which are the outer peripheral fine grinding wheels 55. As the upper and outer peripheral fine grinding stones 55-1 and 55-2, diamond-bonded resin bond grindstones are suitable. Further, the upper and lower outer peripheral spindles 54 and 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 for chamfering the outer periphery of the wafer W is performed in a state of being tilted with respect to 6 to 10 °, that is, with respect to a direction perpendicular to the surface of the wafer W.

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

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

  As the material of the truer 41, a material that can be processed by the outer peripheral rough grinding wheel 52 and that can grind the upper and outer peripheral fine grinding stones 55-1 and 55-2 is adopted. For example, it is desirable that abrasive grains made of silicon carbide be bonded with a phenol resin with a filler added if necessary, and then molded into a disk-like truer 41. The truer 41 may be a disk-shaped GC (Green silicon carbide) grindstone or a WA (White fused aluminum) grindstone having the same thickness as the wafer W to be processed, and the grindstone particle size is # 320. Good degree.

  In addition, the grinding wheel supplies a lubricant to a chamfering wheel material having a porous surface together with a saturated fatty acid solution, and the surface is dried to form a lubricant-impregnated grinding wheel. The grinding stone containing the lubricant is used for water cooling during grinding. It is desirable.

  FIG. 4 is a side view showing a state in which the wafer W is being processed in the outer peripheral fine spindle portion, and the rotation direction and force of the upper outer peripheral fine spindle 54 and the lower outer peripheral fine spindle 57, the inflow and retention of the coolant, It shows the relationship of chip discharge. The upper and outer peripheral fine spindle 54 rotates counterclockwise (rotates from the left to the right as viewed in the direction indicated by the 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 indicated by an arrow A.

  Since the center of the wafer W is held and the outer periphery is a free end, the wafer W is bent downward by a component force. On the other hand, the lower outer periphery precision spindle 57 rotates clockwise (rotates from right to left as viewed in the direction indicated by the arrow B) and tilts upward from right to left in the drawing. Power is added to.

  Since the gap between the upper and outer peripheral precision grinding wheels 55-1 and 55-2 is symmetrical in the center in the rotational axis direction, the wafer W, the upper and outer peripheral precision grinding wheels 55-1 and the lower and outer peripheral precision grinding wheels The contact area with the grindstone 55-2 is equal. Accordingly, the respective grinding resistances are balanced, and no force that bends the wafer W is generated. Thereby, the wafer W does not bend and deform from the center to the tip, and the shape accuracy of the processed surface due to the bending deformation is not affected. Further, the rotational axes of the upper and outer peripheral precision grinding wheels 55-1 and 55-2 are substantially concentric.

  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. 4 along the rotational direction and the counterclockwise direction of the upper outer periphery fine grinding wheel 55-1. Let it flow toward. The lower side is caused to flow from the right side toward the center of the wafer W from the right side in FIG. 4 along the rotation direction and the clockwise direction of the lower outer periphery precision grinding wheel 55-2.

  FIG. 5 is a side view showing the truing process. The truer 41 is attached to the lower part of the wafer table 34 concentrically with the rotation axis of the wafer table and is rotated by the wafer table 34. The wafer table 34 is smaller than the outer peripheral shape of the truer 41. In the truing operation, first, chamfering is performed on the outer periphery of the truer 41 with a master grindstone (not shown). In this processing, the master grindstone is rotated at a rotational speed of 8,000 rpm. In this state, the Z table 31 is moved by the Z-axis drive mechanism 30 and positioned so that the height of the truer 41 coincides with the master groove of the master grindstone.

  The outer peripheral part of the truer 41 is chamfered, and the shape of the master groove is transferred to the outer peripheral part of the truer 41. Grooves are formed on the upper and lower outer peripheral grinding wheels 55-1 and 55-2 whose rotational axes are inclined in the tangential direction of the wafer W using the truer 41 having the master groove cross-sectional shape transferred to the outer peripheral portion. To do. The grooves formed on the outer peripheral grinding wheel 55 are equivalent to those formed with a truing grindstone having an outer diameter equivalent to the outer diameter D of the wafer W.

  FIG. 8 shows the force applied to the truer 41 during the truing process according to the prior art by arrows. In the above description, the outer peripheral fine grinding wheel 55 is described as a set of the upper outer peripheral fine grinding wheel 55-1 and the lower outer peripheral fine grinding wheel 55-2. However, in FIG. Shown as a thing.

  Since the outer peripheral grinding wheel 55 rotates counterclockwise (in the direction indicated by the arrow I) and is inclined downward from left to right in FIG. 8, force is applied to the truer 41 as indicated by the arrow I. The truer 41 is deformed in response to a moment as indicated by arrows G and H. Accordingly, the transfer rate is poor, affecting the accuracy of the grooves formed, the truing time, etc., and the truing efficiency is significantly reduced.

  FIG. 9 shows the range in which the truer 41 and the outer peripheral grinding wheel 55 are in contact with each other by the arrow J during the truing process according to the prior art as in FIG. The contact area between the truer 41 and the outer peripheral grinding wheel 55 becomes wider as the outer circumferential grinding wheel 55 is inclined. For this reason, the discharge performance of coolant and the inflow of coolant are impaired, and the workability deteriorates.

  In the case of FIGS. 8 and 9, in particular, the corner portion at the upper right side of the groove shape to be machined is difficult to have an accurate shape due to deformation of the truer 41, and the accuracy of the machining radius R is deteriorated.

  FIGS. 6 and 7 are explanatory views showing a processing method according to an embodiment, in which the outer peripheral precision grinding wheel 55 is processed by the truer 41. In order to perform helical grinding, the rotational axis of the outer peripheral fine grinding wheel 55 is inclined by 3 to 15 °, preferably 6 to 10 °, with respect to the axis in the thickness direction of the truer 41 perpendicular to the plane of the truer 41. The thickness t is set to be at least 20 to 30% smaller than the groove width h of the outer peripheral grinding wheel 55.

  FIG. 6 shows the upper truing process, and FIG. 7 shows the lower truing process. In FIG. 6, the upper surface of the truer 41 is aligned with the upper part of the predetermined position of the groove formed in the outer peripheral grinding wheel 55. The outer peripheral grinding wheel 55 is pressed against the end surface of the truer 41 from the X direction which is perpendicular to the end surface of the truer 41 and cut. Conversely, the truer 41 may be cut in the X direction with respect to the outer peripheral grinding wheel 55.

  At this time, as described with reference to FIG. 8, a downward force is applied to the truer 41, but the thickness t of the truer 41 is smaller than the groove thickness h of the outer peripheral grinding wheel 55. , Grinding resistance is reduced.

  Next, truing is performed by gradually lowering in the direction of arrow Z toward the bottom of the groove. Finally, as shown in FIG. 7, the process proceeds until the lower part of the groove to be formed is aligned. The order of processing may be reversed as described above, that is, the upper portion may be processed by raising the truer 41 after processing the lower portion. That is, the order of FIGS. 6 and 7 may be reversed. In any case, truing is performed while the truer 41 is swung in the Z direction. Thereby, processability, inflow of coolant, and discharge of silicon are improved, and the transfer rate can be improved.

  Further, the upper grinding (FIG. 6) and the lower grinding (FIG. 7) have been described in this order. However, the present invention is not limited to this, but the central grinding (not shown), the upper grinding (FIG. 6), and the lower grinding. The order of grinding (FIG. 7), center grinding (not shown), lower grinding (FIG. 7), upper grinding (FIG. 6) may be used. First, grinding the center part (not shown) can cut out the shape first, then more carefully and accurately grinding the upper part (FIG. 6) and lower part (FIG. 7). It is excellent in that it can be done.

  Further, by repeating these steps, for example, the upper grinding (FIG. 6) to the lower grinding (FIG. 7) are performed, and the lower grinding (FIG. 7) to the upper grinding (FIG. 6) are performed again to reduce the cutting depth. It is good to cut down while gradually swinging in the Z direction to the desired value. According to this, the force applied to the truer 41 can be further reduced, and the influence of the deformation on the machining accuracy can be reduced.

  Further, the upper surface of the truer 41 has been described as being aligned with the upper part of the groove to be formed in the outer peripheral grinding wheel 55. However, the upper surface of the truer 41 is aligned slightly below the upper part of the groove to be formed, It is also possible to process the corners at. At this time, it is desirable to make the notch of the truer 41 small and repeat it up and down. According to this, the shape of a corner | angular part, a radius, roundness, etc. can be performed more accurately.

  In the truing, when the predetermined outer peripheral surface width, the outer peripheral angle, and the outer peripheral shape are not satisfied as the grinding ability is reduced, the truing 41 is used to appropriately correct the groove (truing). At this time, if the truing of the groove of the grindstone is performed according to the present invention, the number of wafers that can be processed per truing is increased, and the wafer that can be processed with a single resin grindstone even if it is a resin grindstone has an extended life. The number of sheets increases. Therefore, it also leads to cost reduction in the production of the semiconductor wafer.

  W ... Wafer, 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 ... motor, 33 ... θ spindle, 34 ... Wafer table, 40 ... Supply and recovery robot, 41 ... Truer, 50 ... Wheel rotation unit, 51 ... Outer peripheral grinding wheel spindle, 52 ... Outer peripheral rough grinding wheel, 53 ... Turntable, 54 ... Upper outer peripheral precision spindle, 55 ... Outer peripheral precision Grinding wheel, 55-1 ... Upper and outer peripheral fine grinding wheel (upper grinding wheel), 55-2 ... Lower outer peripheral and fine grinding wheel (lower grinding wheel), 56 ... Upper and outer peripheral fine grinding motor, 57 ... Periphery fine Lab spindle, 59 ... lower fixed frame, 62 ... outer circumferential rough grinding device, 70 ... wafer cassette, 71 ... cassette table 80 ... transfer arm

Claims (9)

A truing method for forming a groove of a grindstone for grinding a chamfered portion of a wafer by a disk-shaped truer,
Fixing the plane of the truer whose thickness is smaller than the width of the groove with a table smaller than the outer peripheral shape of the truer in the thickness direction;
Processing the upper or lower portion of the groove at the predetermined position for forming the truer on the grindstone with the truer;
Thereafter, the truer is processed by lowering or raising the truer relative to the grindstone in the thickness direction. A truing method according to claim 1,
The truing method according to claim 1, wherein a rotation axis of the grindstone is inclined with respect to an axis in the thickness direction perpendicular to a plane of the truer. A truing method according to claim 1 or 2,
Processing the central portion at the predetermined position of the groove for forming the truer on the grindstone with the truer,
Thereafter, the truer is processed by raising or lowering the truer in the thickness direction relative to the grindstone. A truing method according to any one of claims 1 to 3,
A truing method, wherein the truer is processed while being swung in the thickness direction relative to the grindstone. A truing method according to any one of claims 1 to 4,
The truing method according to claim 1, wherein a rotation axis of the grindstone is inclined by 3 to 15 degrees with respect to an axis in the thickness direction perpendicular to a plane of the truer. A truing method according to any one of claims 1 to 5,
A truing method wherein the thickness of the truer is 20-30% smaller than the width of the groove. In the chamfering device for chamfering the end face of the plate-shaped workpiece with the groove of the grindstone,
A truer with a disc shape and a thickness smaller than the width of the groove,
A table made smaller than the outer peripheral shape of the truer to fix the plane of the truer in the thickness direction,
The upper or lower portion of the groove at the planned position for forming the truer on the grindstone is processed by the truer, and then the truer is lowered or raised relative to the grindstone in the thickness direction. A chamfering device characterized by. The chamfering device according to claim 7,
The chamfering device according to claim 1, wherein a rotation axis of the grindstone is inclined with respect to an axis in the thickness direction perpendicular to a plane of the truer. The chamfering device according to claim 7 or 8,
The grindstone comprises an upper grinding grindstone and a lower grinding grindstone,
The upper grinding wheel and the lower grinding wheel are attached so that there is a gap and the rotation axis is substantially concentric,
The chamfering apparatus according to claim 1, wherein the groove is formed by the upper grinding wheel and the lower grinding wheel.