JP5268599B2 - Grinding apparatus and grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinder and a grinding method capable of suppressing the damage of a semiconductor wafer having a projection for reinforcement in the disk-like outer peripheral area while the projection for reinforcement is ground without increasing the size of the device. <P>SOLUTION: The semiconductor wafer W includes a device formation area 62 on the front surface of which a device 61 is formed and the outer peripheral area 63 around the device formation area 62. A recess 65 is formed so that the projection for reinforcement projects from the area of the rear surface corresponding to the outer peripheral area 63 by removing the area of the rear surface corresponding to the device formation area 62. The front surface of the semiconductor wafer W is placed on the sucking and holding surface 34a of a chuck table 34. The grinding surface 54a of a grinding wheel 54 is brought into contact with the inner bottom surface 65a of the recess 65 of the semiconductor wafer W diagonally to the projection 64 for reinforcement so that the gap between the grinding surface 54a and the inner bottom surface 65a of the grinding wheel 54 is increased inward of the recess 65. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a grinding apparatus and a grinding method for grinding a semiconductor wafer.

  A semiconductor chip on which a device such as an IC or LSI is formed is indispensable for downsizing various electronic devices. In this semiconductor chip, the surface of a semiconductor wafer as a substantially disk-shaped workpiece is divided into a plurality of rectangular areas by grid-like divided division lines (streets), and devices are formed in each divided rectangular area, and then divided. Manufactured by dividing a rectangular region along a line.

  In such a semiconductor chip manufacturing process, the semiconductor wafer is divided into a predetermined thickness by grinding the back surface on the opposite side of the device surface on which the device is formed prior to the division. By thinning the semiconductor wafer, the heat dissipation is improved in addition to the reduction in size and weight of the electronic device. However, the thinned semiconductor wafer has a problem that the rigidity is lowered as compared with the semiconductor wafer before thinning, and warpage is generated and the conveyance risk is high.

  Therefore, in order to solve this problem, only the region corresponding to the device formation region on which the device is to be formed on the back surface of the semiconductor wafer is ground to form a concave shape, and a reinforcing protrusion is formed in the outer peripheral region of the device region. doing. The rigidity of the semiconductor wafer is ensured by the reinforcing convex portions, and warpage and transport risk are reduced. Thus, the reinforcement convex part is removed from the semiconductor wafer in which the reinforcement convex part was formed before the dicing process.

2. Description of the Related Art Conventionally, as a grinding apparatus for removing a reinforcing convex portion from such a semiconductor wafer, an apparatus for removing the reinforcing convex portion by vertical axis surface grinding is known (for example, see Patent Document 1). As shown in FIG. 6A, the conventional grinding apparatus rotates a thin cylindrical grinding wheel 54 around an axis perpendicular to the semiconductor wafer W, and annular grinding located at the end of the grinding wheel 54 is performed. The surface 54 a is brought into relative rotational contact with the reinforcing convex portion 64 in a parallel state, and the reinforcing convex portion 64 is removed from the back surface of the semiconductor wafer W.
JP 2007-19379 A

  However, the above-described grinding apparatus for vertical axis surface grinding has a problem that the inner bottom surface 65a located inside the reinforcing convex portion 64 of the semiconductor wafer W is damaged even though the grinding wheel 54 is not in contact. It was. Specifically, in the conventional grinding apparatus, since the grinding surface 54a of the grinding wheel 54 is applied in parallel to the reinforcing convex portion 64, the distance between the grinding surface 54a and the inner bottom surface 65a as grinding progresses. Becomes narrower. Then, as shown in FIG. 6B, during the grinding, the abrasive grains 54b fall off from the grinding wheel 54 into the recesses 65, and the abrasive grains 54b are sandwiched between the grinding surface 54a and the inner bottom surface 65a, and the inner bottom surface 65a. The semiconductor wafer W was damaged by dragging the top. In this case, as shown in FIG. 6C, it is conceivable to grind the reinforcing convex portion 64 of the semiconductor wafer W at a position where the grinding surface 54a of the grinding wheel 54 deviates from above the inner bottom surface 65a. The apparatus becomes larger by the amount of movement of the grindstone 54.

  The present invention has been made in view of such points, and in a workpiece in which a reinforcing convex portion is formed in a disk-shaped outer peripheral region, the workpiece is damaged during grinding of the reinforcing convex portion without increasing the size of the apparatus. An object of the present invention is to provide a grinding apparatus and a grinding method capable of suppressing the above.

  The grinding apparatus of the present invention has a mounting surface on which a workpiece is mounted, a holding portion that holds the workpiece on the mounting surface, and a grinding wheel that hits the workpiece held on the holding portion. An area corresponding to the device forming area on the back surface, and the workpiece has a device forming area where a device is formed on the surface and an outer peripheral area around the device forming area. And a concave portion is formed so that a reinforcing convex portion protrudes from a region corresponding to the outer peripheral region on the back surface, and the surface of the workpiece is placed on the placement surface of the holding portion. The grinding surface of the grinding wheel is in contact with the reinforcing convex portion diagonally so that the distance between the grinding surface of the grinding wheel and the inner bottom surface widens toward the inside of the concave portion with respect to the inner bottom surface of the concave portion It is characterized by making it.

  The grinding method of the present invention has a mounting surface on which a workpiece is mounted, a holding portion that holds the workpiece on the mounting surface, and a grinding stone applied to the workpiece held on the holding portion. A grinding method for grinding the workpiece by a grinding apparatus provided with a grinding section for contacting and grinding, wherein the workpiece includes a device forming region in which a device is formed on a surface, and an outer peripheral region around the device forming region. And removing the region corresponding to the device forming region on the back surface, forming a recess so that the reinforcing convex portion protrudes from the region corresponding to the outer peripheral region on the back surface, and holding the surface of the workpiece The grinding wheel is ground so that a gap between the grinding surface of the grinding wheel and the inner bottom surface widens toward the inside of the concave portion with respect to the inner bottom surface of the concave portion of the workpiece. The surface is inclined to the reinforcing convex part Characterized by grinding in contact.

  According to this configuration, when the grinding surface of the grinding wheel and the reinforcing convex portion contact each other, the gap between the grinding surface and the inner bottom surface of the grinding wheel widens toward the inside of the concave portion, so that the grinding wheel falls off from the grinding wheel. In the state where the abrasive grains are sandwiched between the grinding surface and the inner bottom surface, it is suppressed that the abrasive grains are dragged on the inner bottom surface. Therefore, even if abrasive grains fall out during grinding of the reinforcing convex portion, damage to the workpiece can be suppressed. In addition, the grinding surface of the grinding wheel and the reinforcing convex part are inclined to suppress the sandwiching of the abrasive grains, so that the grinding surface of the grinding wheel is moved from above the inner bottom surface to a position outside the workpiece. The apparatus can be downsized as compared with the above. In general, since the grinding device grinds while spraying grinding water, the fallen abrasive grains are flowed to the outside of the recess with the grinding water, and the abrasive grains are further prevented from being sandwiched between the grinding surface and the inner bottom surface. Is done.

  Further, according to the grinding apparatus of the present invention, the grinding wheel has a ring-shaped grinding surface, and the ring-shaped grinding surface of the grinding wheel and the reinforcing convex portion are in contact with each other at one part. The grinding surface of the grinding wheel is in contact with the reinforcing convex portion obliquely.

  Further, according to the grinding apparatus of the present invention, the work is inclined relative to the grinding surface of the grinding wheel in a first direction passing from the outer periphery to the center of the work and is orthogonal to the first direction. In the second direction, the workpiece is inclined relative to the grinding surface of the grinding wheel so that the ring-shaped grinding surface of the grinding wheel and the reinforcing convex portion are in contact with each other in one part. The grinding surface of the grinding wheel is in contact with the reinforcing convex portion obliquely.

  In addition, according to the grinding apparatus of the present invention, an inclination angle adjustment mechanism that adjusts an inclination angle of the holding portion is provided, and an inclination angle of the holding portion is adjusted by the inclination angle adjustment mechanism so that an inner bottom surface of the concave portion of the workpiece is provided. On the other hand, the grinding surface of the grinding wheel is in contact with the reinforcing convex portion obliquely so that the distance between the grinding surface of the grinding wheel and the inner bottom surface widens toward the inside of the concave portion.

  In addition, according to the grinding method of the present invention, the grinding wheel has a ring-shaped grinding surface, and the grinding wheel has a ring-shaped grinding surface and the reinforcing convex portion are in contact with one part. The ground surface is ground in contact with the reinforcing convex portion at an angle.

  ADVANTAGE OF THE INVENTION According to this invention, in the workpiece | work which formed the convex part for reinforcement in the disk-shaped outer peripheral area | region, damage to a workpiece | work can be suppressed during grinding of the convex part for reinforcement, without enlarging an apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The grinding apparatus according to the present embodiment is for removing the reinforcing convex portions formed on the outer peripheral edge portion of the back surface of the semiconductor wafer before the dicing process in order to reduce warpage and conveyance risk. First, before describing the grinding apparatus according to the embodiment of the present invention, a semiconductor wafer to be ground will be briefly described. FIG. 1 is an external perspective view of a semiconductor wafer before processing according to an embodiment of the present invention, where (a) shows the front surface of the semiconductor wafer and (b) shows the back surface of the semiconductor wafer.

  As shown in FIG. 1A, the unprocessed semiconductor wafer W is formed in a substantially disc shape, and is partitioned into a plurality of regions by unscheduled division lines (not shown) arranged in a lattice pattern on the surface. . A device 61 such as an IC or LSI is formed in the center of the semiconductor wafer W in each region partitioned by the division lines. Further, the surface of the semiconductor wafer W is divided into a device forming region 62 in which the device 61 located at the central portion is formed and an outer peripheral region 63 positioned around the device forming region 62.

  As shown in FIG. 1B, the back surface of the semiconductor wafer W has a region corresponding to the device forming region 62 removed, and a region corresponding to the outer peripheral region 63 protrudes in an annular shape to form a reinforcing convex portion 64. Yes. As described above, the recess 65 is formed on the back surface of the semiconductor wafer W, and only the device formation region 62 is thinned. The semiconductor wafer W in which the recess 65 is formed is accommodated in the cassette 2 (see FIG. 2) and is carried into the grinding apparatus 1.

  In the present embodiment, a semiconductor wafer W such as a silicon wafer will be described as an example of a workpiece. However, the present invention is not limited to this configuration, and the semiconductor product package, ceramic, glass, sapphire, silicon Substrate, various electrical components, and various processing materials that require micron order accuracy may be used as the workpiece. Further, the reinforcing convex portion 64 is not limited to the one formed in an annular shape, and may be any one that reinforces the warp and strength of the workpiece, and may be formed in an arc shape, for example.

  Next, a grinding apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 2 is an external perspective view of the grinding apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, the grinding device 1 carries in a semiconductor wafer W before processing, a loading / unloading unit 4 for unloading the semiconductor wafer W after processing, and a semiconductor wafer W loaded from the loading / unloading unit 4. It is comprised from the convex part removal unit 5 which grinds and removes the convex part 64 for a reinforcement. The carry-in / carry-out unit 4 has a rectangular parallelepiped base 11, and the base 11 is provided with a pair of cassette placement portions 12 and 13 on which the cassettes 2 and 3 are placed so as to protrude forward from the front surface 11a. It has been.

  The cassette mounting unit 12 functions as a carry-in port, and the cassette 2 in which the unprocessed semiconductor wafer W is stored is mounted. The cassette mounting portion 13 functions as a carry-out port, and the cassette 3 in which the processed semiconductor wafer W is accommodated is mounted. On the upper surface of the base 11, a carry-in / carry-out arm 14 is provided so as to face the cassette mounting parts 12, 13, and the temporary placement part is adjacent to the carry-in / carry-out arm 14 at one corner on the convex part removal unit 5 side. 15. Spinner cleaning units 16 are provided at the other corners, respectively. Further, on the upper surface of the base 11, a wafer supply unit 17 and a wafer recovery unit 18 are provided between the temporary placement unit 15 and the spinner cleaning unit 16.

  The carry-in / carry-out arm 14 carries the semiconductor wafer W from the cassette 2 placed on the cassette placement unit 12 to the temporary placement unit 15, and from the spinner cleaning unit 16 to the cassette 3 placed on the cassette placement unit 13. The semiconductor wafer W is unloaded. The temporary placement unit 15 includes a temporary placement table 21 and an imaging unit 22, images the outer peripheral portion of the semiconductor wafer W placed on the temporary placement table 21, and the center position of the semiconductor wafer W by image processing. And a position shift amount between the center position of the temporary placement table 21 (a center position of a chuck table 34 described later).

  The wafer supply unit 17 places the semiconductor wafer W on the chuck table 34 of the convex portion removal unit 5 while correcting the positional shift amount of the unprocessed semiconductor wafer W placed on the temporary placement table 21. The wafer recovery unit 18 places the processed semiconductor wafer W placed on the chuck table 34 on the spinner cleaning table 23 of the spinner cleaning unit 16. The spinner cleaning unit 16 rotates the semiconductor wafer W placed on the spinner cleaning table 23 in the base 11 and sprays cleaning water to clean it.

  The convex portion removing unit 5 is configured to grind the reinforcing convex portion 64 of the semiconductor wafer W by relatively rotating the rough grinding unit 32 and the finish grinding unit 33 and the chuck table 34 holding the semiconductor wafer W. . The convex portion removal unit 5 has a rectangular parallelepiped base 31, and the carry-in / out unit 4 is connected to the front surface of the base 31. A turntable 35 on which three chuck tables 34 are arranged is provided on the upper surface of the base 31, and a column portion 36 is erected on the rear side of the turntable 35.

  The turntable 35 is formed in a large-diameter disk shape, and three chuck tables 34 are arranged on the upper surface at intervals of 120 degrees in the circumferential direction. The turntable 35 is connected to a rotation drive mechanism (not shown), and is intermittently rotated at intervals of 120 degrees in the direction D1 by the rotation drive mechanism. As a result, the three chuck tables 34 have a transfer position where the semiconductor wafer W is transferred between the wafer supply unit 17 and the wafer recovery unit 18, a rough grinding position where the semiconductor wafer W faces the rough grinding unit 32, and finish grinding. The unit 33 is moved between finish grinding positions where the semiconductor wafer W is opposed to the unit 33. Details of the chuck table 34 will be described later.

  On the upper surface of the base 31, contact sensors 38 and 39 are provided in the vicinity of the rough grinding position and the finish grinding position of the turntable 35. The contact sensors 38 and 39 have two contacts. One contact is in contact with the reinforcing convex portion 64 of the semiconductor wafer W, and the other contact is in contact with the upper surface of the chuck table 34. . The grinding depth is controlled from the difference in height between the two contacts.

  The support column 36 is formed in a base shape having a pair of slopes as viewed from above. Grinding unit moving mechanisms 41 and 42 for moving the rough grinding unit 32 and the finish grinding unit 33 above the chuck table 34 are provided on the pair of slopes. Is provided. The pair of inclined surfaces of the support column 36 are at angles that allow the rough grinding unit 32 and the finish grinding unit 33 to move toward the center of the corresponding chuck table 34, respectively. The grinding unit moving mechanism 41 includes a pair of guide rails (not shown) arranged on the slope of the support column 36 and parallel to each other in the left-right direction, and a motor-driven R-axis table 43 slidably installed on the pair of guide rails. Have.

  The grinding unit moving mechanism 41 includes a pair of guide rails 45 disposed in front of the R-axis table 43 and parallel to each other in the vertical direction, and a motor-driven Z disposed slidably on each of the pair of guide rails 45. A shaft table 46 is provided. The rough grinding unit 32 is supported on the Z-axis table 46 via a support portion 47 attached to the front surface. The grinding unit moving mechanism 42 also has the same configuration as the grinding unit moving mechanism 41, and the finish grinding unit 33 is supported.

  A nut portion (not shown) is formed on the back side of each R-axis table 43, 44 and each Z-axis table 46, and a ball screw 48 is screwed to these nut portions (the ball screw for the R-axis table is Not shown). A drive motor 49 is connected to the upper ends of the ball screws for the R-axis tables 43 and 44 and the ball screw 48 for the Z-axis table 46, and the ball screws are rotationally driven by the drive motor 49 (for the R-axis table). The drive motor is not shown). With such a configuration, the R-axis tables 43 and 44 move in the R1 direction and the R2 direction, respectively, and the Z-axis table 46 moves in the vertical direction.

  The rough grinding unit 32 includes a unit housing 51, a spindle (not shown) that is rotationally driven by a motor 52 inside the unit housing 51, and a grinding wheel 54 that is detachably attached to the lower end of the spindle. The rough grinding unit 32 causes the grinding wheel 54 to rotate and come into contact with the semiconductor wafer W held on the rotated chuck table 34, and sprays a grinding liquid onto the semiconductor wafer W from a nozzle (not shown). Then, the rough grinding unit 32 is positioned in the radial direction of the grinding wheel 54 with respect to the semiconductor wafer W by the grinding unit moving mechanism 41 and is ground and fed in the Z-axis direction to remove the reinforcing convex portion 64 from the semiconductor wafer W.

  The grinding wheel 54 is composed of a diamond wheel in which diamond abrasive grains are hardened with a binder such as a metal bond or a resin bond. The grinding wheel 54 is formed in a thin cylindrical shape and has a ring-shaped grinding surface. The finish grinding unit 33 has the same configuration as that of the rough grinding unit 32 and performs the same operation. However, a fine grindstone 54 is used as the grinding wheel 54.

  Next, the chuck table will be described in detail with reference to FIG. FIG. 3 is an external perspective view of the chuck table according to the embodiment of the present invention. In FIG. 3, only the table portion is shown for convenience of explanation.

  As shown in FIG. 3, the chuck table 34 has a disc shape, and a suction holding surface 34 a is formed in a circular shape by a porous ceramic material at a central portion of the upper surface. The suction holding surface 34 a is connected to a suction source (not shown) disposed in the base 31 and holds the semiconductor wafer W by suction. The chuck table 34 is configured to be rotatable in the D2 direction around an axis L perpendicular to the suction holding surface 34a by a rotation driving mechanism (not shown).

  An inclination angle adjustment mechanism 55 is provided below the chuck table 34 between the upper surface of the turntable 35. The tilt angle adjusting mechanism 55 finely adjusts the tilt angle of the chuck table 34 with respect to the grinding surface of the grinding wheel 54, and is configured so that the tilt angles in two orthogonal θ1 and θ2 directions can be finely adjusted. . The θ1 direction is an angle adjustment direction in the R1 direction (R2 direction), which is the moving direction of the R-axis table 43, and the θ2 direction is an angle adjustment direction in a direction orthogonal to the R1 direction (R2 direction). When the chuck table 34 is tilted in the θ1 direction, it comes into contact with the ring-shaped grinding surface of the grinding wheel 54 at two locations (see FIG. 4C). Further, when the chuck table 34 is tilted in the θ2 direction, the grinding wheel 54 It contacts with the ring-shaped grinding surface of this in one place (refer FIG. 5).

  The tilt angle adjusting mechanism 55 may be configured to adjust the tilt angle of the chuck table 34 with respect to the grinding surface of the grinding wheel 54. For example, the tilt angle adjusting mechanism 55 is configured by combining two seesaw mechanisms. Further, in the present embodiment, the tilt angle adjusting mechanism 55 can finely adjust the tilt angle in two directions. However, a mechanism that can adjust only one direction may be used.

  Here, the grinding operation by the grinding apparatus according to the present embodiment will be described. FIG. 4 is an explanatory diagram of a grinding operation when the chuck table is tilted in only one direction by the grinding apparatus according to the present embodiment. In the following description, the case where the reinforcing convex portion of the semiconductor wafer is ground by the rough grinding unit will be described as an example, but the finish grinding unit operates in the same manner. Further, in the present embodiment, a configuration in which the inclination angle in the θ1 direction of the inclination angle adjusting mechanism 55 is adjusted and brought into contact with the ring-shaped grinding surface of the grinding wheel 54 will be described as an example.

  In the chuck table 34, the surface of the semiconductor wafer W is placed on the suction holding surface 34 a at the replacement position by the wafer supply unit 17, and the semiconductor wafer W is held on the suction holding surface 34 a with the reinforcing convex portion 64 facing upward. In this state, the turntable 35 moves to the rough grinding position. At this time, the R-axis table 43 moves, and the grinding position in the radial direction of the rough grinding unit 32 with respect to the semiconductor wafer W is adjusted.

  As shown in FIG. 4A, when the chuck table 34 moves to the rough grinding position, the tilt angle is adjusted by the tilt angle adjusting mechanism 55. The tilt angle adjusting mechanism 55 slightly tilts the chuck table 34 in the θ1 direction in the R1 direction to widen the distance between the grinding surface 54a of the grinding wheel 54 and the inner bottom surface 65a of the recess 65 of the semiconductor wafer W. That is, the angle between the grinding surface 54a and the inner bottom surface 65a of the semiconductor wafer W is adjusted so as to increase toward the center of the semiconductor wafer W in the R1 direction.

  As shown in FIG. 4 (b), when the rough grinding unit 32 is ground and fed downward by the Z-axis table 46, the grinding surface 54 a of the grinding stone 54 contacts the reinforcing convex portion 64 of the semiconductor wafer W obliquely. . At this time, as shown in FIG. 4C, the grinding surface 54 a of the grinding wheel 54 is in contact with the reinforcing convex portion 64 of the semiconductor wafer W at two locations of contact portions A <b> 1 and A <b> 2.

  In this state, when the grinding of the semiconductor wafer W is continued, the abrasive grains 54 b fall off from the grinding wheel 54 into the recess 65 of the semiconductor wafer W. The abrasive grains 54b that have fallen into the recesses 65 are prevented from being sandwiched between the grinding surface 54a and the inner bottom surface 65a because the gap between the grinding surface 54a of the grinding wheel 54 and the inner bottom surface 65a of the semiconductor wafer W is wide. . In addition, the abrasive grains 54b that have fallen into the recesses 65 are washed away to the outside of the recesses 65 by the grinding water sprayed from the nozzles, so that the abrasive grains 54b that have fallen between the grinding surface 54a and the inner bottom surface 65a become the semiconductor wafer W. The problem of damaging the inner bottom surface 65a can be prevented.

  Next, the grinding operation when the chuck table is tilted in two directions by the grinding apparatus will be described with reference to FIG. FIG. 5 is an explanatory diagram of a grinding operation when the chuck table is tilted in two directions by the grinding apparatus according to the present embodiment.

  In the configuration shown in FIG. 4C, since the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 of the semiconductor wafer W are in contact with each other at two locations, the reinforcing convex portion 64 is in the contact portions A1 and A2. The direction of grinding is different. That is, when the grinding wheel 54 rotates in the direction D3, the reinforcing convex portion 64 is in the direction in which the ring-shaped grinding surface 54a of the grinding stone 54 protrudes from the inner side to the outer side of the reinforcing convex portion 64 of the semiconductor wafer W at the contact portion A1. In the contact portion A2, the reinforcing convex portion 64 is ground in such a direction that the ring-shaped grinding surface 54a of the grinding wheel 54 enters from the outside to the inside of the reinforcing convex portion 64 of the semiconductor wafer W.

  Thus, if the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 of the semiconductor wafer W are different in the grinding direction, vibrations are generated to cause abnormal wear of the grinding wheel 54, increased edge chipping, There is a possibility of being affected by abnormal vibration, reduction of surface roughness, etc. In this case, as shown in FIG. 5, the chuck table 34 is inclined in two directions of the θ1 direction and the θ2 direction, and the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 of the semiconductor wafer W are connected to the contact portion A3. It is set as the structure made to contact in one place. Thus, since the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 of the semiconductor wafer W come into contact with each other, abnormal wear of the grinding wheel 54, increase in edge chipping, abnormal vibration, and reduction in surface roughness are achieved. Can be suppressed.

  As described above, according to the grinding apparatus 1 according to the present embodiment, when the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 contact each other, the grinding surface 54a of the grinding wheel 54 and the semiconductor wafer W Since the distance from the inner bottom surface 65a increases toward the inside of the concave portion 65, the abrasive grains 54b are removed from the grinding wheel 54 between the grinding surface 54a and the inner bottom surface 65a. Dragging on 65a is suppressed. Therefore, even if the abrasive grains 54b fall off during the grinding of the reinforcing convex portion 64, the semiconductor wafer W can be prevented from being damaged. Further, since the grinding surface 54a of the grinding wheel 54 and the reinforcing convex portion 64 are inclined to suppress the sandwiching of the abrasive grains 54b, the grinding surface 54a of the grinding wheel 54 is positioned away from above the inner bottom surface 65a. The apparatus can be downsized as compared with the configuration in which the apparatus is moved to the position.

  In the above-described embodiment, the θ1 direction is the angle adjustment direction in the R1 direction (R2 direction), which is the moving direction of the R-axis table 43, and the θ2 direction is the angle adjustment direction in the direction orthogonal to the R1 direction (R2 direction). However, it is not limited to this direction. As long as the distance between the grinding surface 54a and the inner bottom surface 65a of the semiconductor wafer W increases toward the inside of the recess 65 of the semiconductor wafer W, any direction is acceptable.

  In the above-described embodiment, the reinforcing convex portion 64 is removed by grinding. However, the reinforcing convex portion 64 does not need to be completely removed and does not affect the subsequent dicing process. Can be removed.

  In the above-described embodiment, the chuck table 34 is inclined with respect to the grinding surface 54 a of the grinding wheel 54, and the grinding surface 54 a of the grinding wheel 54 and the reinforcing convex portion 64 of the semiconductor wafer W are brought into contact with each other. However, it is not limited to this configuration. Any configuration may be used as long as the chuck table 34 is inclined relative to the grinding surface 54 a of the grinding wheel 54, and the grinding surface 54 a of the grinding wheel 54 may be inclined relative to the chuck table 34. In this case, a θ table is provided between the Z-axis table 46 and the support portion 47, and the grinding surface 54 a of the grinding wheel 54 is inclined with respect to the chuck table 34. Further, the grinding surface 54a of the grinding wheel 54 and the chuck table 34 may be tilted by the tilt angle adjusting mechanism 55 and the θ table.

  In the above-described embodiment, the cylindrical grinding wheel 54 is used for grinding. However, the reinforcing convex portion 64 may be ground from the semiconductor wafer W. For example, a cup-shaped grinding wheel or the like A cylindrical grinding wheel having no ring-shaped grinding surface may be used. Further, when the grinding surface is inclined in a conical shape, the interval between the grinding surface 54a of the grinding wheel 54 and the inner bottom surface 65a of the semiconductor wafer W is recessed without driving the tilt angle adjusting mechanism 55 or the θ table. It becomes possible to expand toward the inside of 65.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the present invention suppresses damage to the workpiece during grinding of the reinforcing convex portion without increasing the size of the device in the workpiece in which the reinforcing convex portion is formed in the disk-shaped outer peripheral region. In particular, the present invention is useful for a grinding apparatus and a grinding method for grinding a semiconductor wafer.

It is a figure which shows embodiment of the grinding apparatus which concerns on this invention, and is an external appearance perspective view of the semiconductor wafer before a process. It is a figure which shows embodiment of the grinding device which concerns on this invention, and is an external appearance perspective view of a grinding device. It is a figure which shows embodiment of the grinding device which concerns on this invention, and is an external appearance perspective view of the chuck table of a grinding device. It is a figure which shows embodiment of the grinding device which concerns on this invention, and is explanatory drawing of grinding operation at the time of making the chuck table by a grinding device incline only to one direction. It is a figure which shows embodiment of the grinding apparatus which concerns on this invention, and is explanatory drawing of grinding operation at the time of making a chuck table incline in 2 directions. It is explanatory drawing of the grinding operation of the conventional grinding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Grinding device 4 Loading / unloading unit 5 Convex part removal unit 31 Base 32 Rough grinding unit (grinding part)
33 Finishing grinding unit (grinding part)
34 Chuck table (holding part)
34a Adsorption holding surface (mounting surface)
35 Turntable 41, 42 Grinding unit moving mechanism 54 Grinding wheel 54a Grinding surface 54b Abrasive grain 55 Inclination angle adjusting mechanism 61 Device 62 Device forming area 63 Outer peripheral area 64 Reinforcing convex part 65 Concave part 65a Inner bottom surface W Semiconductor wafer

Claims (6)

A holding portion on which the workpiece is placed, and a holding portion for holding the workpiece on the placement surface;
A grinding part that grinds the workpiece held by the holding part by bringing a grinding wheel into contact with the workpiece,
The workpiece has a device forming region where a device is formed on the front surface and an outer peripheral region around the device forming region, and removes a region corresponding to the device forming region on the back surface to the outer peripheral region on the back surface. A concave portion is formed so that the reinforcing convex portion protrudes from the corresponding region, and the surface of the workpiece is placed on the placement surface of the holding portion,
The grinding surface of the grinding wheel is inclined with respect to the reinforcing convex portion so that the distance between the grinding surface of the grinding wheel and the inner bottom surface widens toward the inside of the concave portion with respect to the inner bottom surface of the concave portion of the workpiece. A grinding apparatus characterized by contacting. The grinding wheel has a ring-shaped grinding surface,
2. The grinding surface of the grinding wheel is brought into contact with the reinforcing convex portion obliquely so that the ring-shaped grinding surface of the grinding wheel and the reinforcing convex portion are in contact with each other at one part. The grinding apparatus described in 1.   The workpiece is inclined relative to the grinding surface of the grinding wheel in a first direction passing through the center from the outer periphery of the workpiece, and the workpiece is ground in a second direction orthogonal to the first direction. The reinforcing surface of the grinding wheel is inclined relative to the grinding surface of the grinding wheel so that the ring-shaped grinding surface of the grinding wheel and the reinforcing convex portion are in contact with each other. The grinding apparatus according to claim 2, wherein the grinding apparatus is brought into contact with each other at an angle. An inclination angle adjusting mechanism for adjusting the inclination angle of the holding portion;
The inclination angle of the holding portion is adjusted by the inclination angle adjustment mechanism so that the distance between the grinding surface of the grinding wheel and the inner bottom surface is widened toward the inside of the concave portion with respect to the inner bottom surface of the concave portion of the workpiece. The grinding apparatus according to claim 1, wherein a grinding surface of the grinding wheel is brought into contact with the reinforcing convex portion obliquely. A holding portion on which the workpiece is placed, and a holding portion for holding the workpiece on the placement surface;
A grinding method for grinding the workpiece by a grinding device comprising a grinding unit that abuts a grinding wheel against the workpiece held by the holding unit and grinds the workpiece,
The workpiece has a device forming region where a device is formed on the front surface and an outer peripheral region around the device forming region, and removes a region corresponding to the device forming region on the back surface to the outer peripheral region on the back surface. A concave portion is formed so that the reinforcing convex portion protrudes from the corresponding region, and the surface of the workpiece is placed on the placement surface of the holding portion,
The grinding surface of the grinding wheel is inclined with respect to the reinforcing convex portion so that the distance between the grinding surface of the grinding wheel and the inner bottom surface widens toward the inside of the concave portion with respect to the inner bottom surface of the concave portion of the workpiece. A grinding method comprising grinding by contact. The grinding wheel has a ring-shaped grinding surface,
The grinding surface of the grinding wheel is in contact with the reinforcing convex portion obliquely so that the ring-shaped grinding surface of the grinding wheel and the reinforcing convex portion are in contact with each other. Item 6. The grinding method according to Item 5.

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