Polishing apparatus and polishing method

Abstract

The present invention realizes a polishing apparatus capable of chamfering an end face of a large-sized substrate at a high precision for a table unit for mounting the substrate. A substrate is mounted on a table unit and is fixedly held in a predetermined reference state. A first polishing unit includes a polishing grind stone for polishing an end face of the substrate held on the table unit and substrate side edge portion supporting means for supporting the lower surface of a side edge portion of the substrate in the vicinity of the end face of the substrate to be polished by the polishing unit. The first polishing unit is moved together with the substrate side edge portion supporting means by a first polishing unit moving means along the end face of the substrate while the polishing grind stone is polishing the end face of the substrate.

1 . A polishing apparatus comprising:
 a table unit, having a substrate mounted thereon, for fixedly holding the substrate in a predetermined reference state;   a first polishing unit including a polishing grind stone for polishing an end face of the substrate held on the table unit and substrate side edge portion supporting means for supporting a lower surface of a side edge portion of the substrate in a vicinity of the end face of the substrate to be polished by the polishing grind stone; and   a first polishing unit moving means for moving, together with the substrate side edge portion supporting means, the first polishing unit along the end face of the substrate while the polishing grind stone is polishing the end face of the substrate.   
   
   
       2 . A polishing apparatus according to  claim 1 , wherein the first polishing unit further includes substrate side edge portion holding means for holding an upper surface of the side edge portion of the substrate supported by the substrate side edge portion supporting means. 
   
   
       3 . A polishing apparatus according to  claim 1 , wherein the substrate side edge portion supporting means supports a lower surface of the substrate by a member having a low friction coefficient. 
   
   
       4 . A polishing apparatus according to  claim 2 , wherein the substrate side edge portion holding means holds an upper surface of the substrate by a member having a low friction coefficient. 
   
   
       5 . A polishing apparatus according to  claim 3 , wherein the material having the low friction coefficient is a free bearing. 
   
   
       6 . A polishing apparatus according to  claim 4 , wherein the material having the low friction coefficient is a free bearing. 
   
   
       7 . A polishing apparatus according to  claim 1 , wherein the table unit includes a center table, having a central portion of the lower surface of the substrate mounted thereon, for suctioning and holding the central portion. 
   
   
       8 . A polishing apparatus according to  claim 7 , wherein the table unit includes a plurality of substrate auxiliary supporting means, the plurality of substrate auxiliary supporting means being arranged around the center table to respectively support side portions of the lower surface of the substrate held on the center table. 
   
   
       9 . A polishing apparatus according to  claim 8 , wherein the substrate auxiliary supporting means includes an auxiliary supporting base for supporting the lower surface of the substrate, and the auxiliary supporting base is structured to support the lower surface of the substrate by a member having a low friction coefficient. 
   
   
       10 . A polishing apparatus according to  claim 9 , wherein the material having the low friction coefficient is a free bearing. 
   
   
       11 . A polishing apparatus according to  claim 8 , wherein the substrate auxiliary supporting means includes an auxiliary supporting base for supporting the lower surface of the substrate, and the auxiliary supporting base has means for suctioning and holding the lower surface of the substrate provided thereon. 
   
   
       12 . A polishing apparatus according to  claim 9 , wherein the substrate auxiliary supporting means includes a sliding mechanism for sliding the auxiliary supporting base closer to or away from the center table. 
   
   
       13 . A polishing apparatus according to  claim 11 , wherein the substrate auxiliary supporting means includes a sliding mechanism for sliding the auxiliary supporting base closer to or away from the center table. 
   
   
       14 . A polishing apparatus according to  claim 8 , wherein the table unit further includes a table rotating mechanism for rotating the center table. 
   
   
       15 . A polishing apparatus according to  claim 14 , wherein the table rotating mechanism rotates the substrate auxiliary supporting means together with the center table in an integrated manner. 
   
   
       16 . A polishing apparatus according to  claim 14 , wherein the first polishing unit and the first polishing unit moving means are attached to a first polishing unit holding body, the first polishing unit holding body having a first horizontal beam being arranged along the end face of the substrate held on the table unit, and the first polishing unit holding body is movable in a vertical direction with respect to the first horizontal beam. 
   
   
       17 . A polishing apparatus according to  claim 16 , wherein the first polishing unit is attached to be movable along the first horizontal beam of the first polishing unit holding body, and the first polishing unit moving means moves the first polishing unit along the first horizontal beam. 
   
   
       18 . A polishing apparatus according to  claim 16 , wherein an image capturing device is provided on the first polishing unit, the image capturing device being for capturing an image of an alignment mark provided on the substrate,
 the polishing apparatus further comprising:   an image processing device for computing image data of the alignment mark captured by the image capturing device; and   a control section for computing a rotation angle with respect to the reference state of the substrate mounted on the center unit based on positional data of the alignment mark computed by the image processing device.   
   
   
       19 . A polishing apparatus according to  claim 17 , further comprising:
 a second polishing unit including a polishing grind stone for polishing an end face, the end face being positioned on the opposite side of the end face to be polished by the first polishing unit for the substrate held on the table unit and substrate side edge portion supporting means for supporting the lower surface of the side edge portion of the substrate in the vicinity of the end face of the substrate to be polished by the polishing grind stone; and   second polishing unit moving means for moving, together with the substrate side edge portion supporting means, the second polishing unit along the end face of the substrate while the polishing grind stone is polishing the end face of the substrate,   wherein   the second polishing unit and the second polishing unit moving means are attached to a second polishing unit holding body including a second horizontal beam in parallel with the first horizontal beam of the first polishing unit holding body, and the second polishing unit holding body is capable of being translated in a horizontal direction with respect to the second horizontal beam.   
   
   
       20 . A polishing apparatus according to  claim 19 , wherein the table rotating mechanism rotates the center table such that the substrate mounted on the center table is put in a state of being rotated by a predetermined angle of 30 to 60 degrees with respect to the reference state, and
 the first polishing unit and the second polishing unit simultaneously polish the end faces facing each other of the substrate held on the rotated center table, respectively.   
   
   
       21 . A polishing apparatus comprising:
 a table unit, having a substrate mounted thereon, for fixedly holding the substrate in a reference state;   four polishing units each including a polishing grind stone for polishing one of four respective end faces of the substrate held on the table unit and substrate side edge portion supporting means for supporting respective lower face of a side edge portion of the substrate in a vicinity of the respective end face of the substrate to be polished by the respective grind stone;   four unit moving means each for moving, together with the respective substrate side edge portion supporting means, the respective polishing unit along the respective end face of the substrate while each polishing grind stone is polishing the respective end face of the substrate; and   four polishing unit transfer mechanism each for moving the respective polishing unit in a direction to move closer to or away from the respective end face of the substrate.   
   
   
       22 . A polishing apparatus according to  claim 21 , wherein an image capturing device is provided on each polishing unit, the image capturing device being for capturing an image of an alignment mark provided on the substrate and capturing a polishing site by each polishing grind stone,
 the polishing apparatus further comprising:   an image processing device for computing image data of the alignment mark and the polishing site obtained from each image capturing device; and   a control section for computing a rotation angle with respect to the reference state of the substrate mounted on the center unit based on positional data of the alignment mark computed by the image processing device and for computing a polishing amount of each end face to control the respective polishing unit transfer mechanism.   
   
   
       23 . A polishing apparatus according to  claim 22 , wherein each polishing unit includes an air blowing device between the image capturing device and the polishing grind stone, respectively, for blowing air on the respective image capturing device. 
   
   
       24 . A polishing method for an end face of a substrate by a polishing apparatus according to  claim 1 , comprising:
 a holding step of mounting the substrate on the table unit and fixedly holding the substrate in the reference state by the table unit;   a supporting step of supporting a side edge portion of the substrate held on the table unit by the substrate side edge portion supporting means of the first polishing unit; and   a moving step of moving, while the polishing grind stone of the first polishing unit is polishing the end face of the side edge portion supported by the substrate side edge portion supporting means, the first polishing unit along the end face being polished by the first polishing unit moving means.   
   
   
       25 . A polishing method according to  claim 24 , wherein the first polishing unit of the polishing apparatus includes substrate side edge portion holding means for holding an upper surface of the side edge portion of the substrate supported by the substrate side edge portion supporting means,
 the method further comprising:   a holding step of the substrate side edge portion holding means holding, subsequent to the supporting step, the upper surface of the side edge portion of the substrate supported by the substrate side edge portion supporting means.   
   
   
       26 . A polishing method according to  claim 24 , wherein the center table includes suction means for suctioning a central portion of the substrate, and
 in the holding step, the central portion of the substrate is suctioned by the suction means of the center table.   
   
   
       27 . A polishing method according to  claim 26 , wherein the table unit of the polishing apparatus includes a plurality of substrate auxiliary supporting means, the plurality of substrate auxiliary supporting means being arranged around the center table to respectively support side portions of the lower surface of the substrate held on the center table, and
 in the holding step, a side portion of a lower surface of the substrate fixedly held on the center table is supported by at least one of the plurality of substrate auxiliary supporting means.   
   
   
       28 . A polishing method according to  claim 27 , wherein the substrate auxiliary supporting means of the polishing apparatus includes a sliding mechanism for sliding the auxiliary supporting base to move closer or away from the center table, and
 in the holding step, the substrate auxiliary supporting means is slid to support the side portion of the substrate fixedly held on the center table.   
   
   
       29 . A polishing method according to  claim 24 , wherein the table unit of the polishing apparatus includes a table rotating mechanism for rotating the center table, and
 in the holding step, the end face of the substrate is rotated by the rotating mechanism so as to be along a moving direction of the first polishing unit by the first polishing unit moving means.   
   
   
       30 . A polishing method according to  claim 24 , wherein the first polishing unit and the first polishing unit moving means of the polishing apparatus are attached to a first polishing unit holding body, the first polishing unit holding body having a horizontal beam being arranged along the end face of the substrate held on the table unit, and the first polishing unit holding body is capable of being translated in a vertical direction with respect to the horizontal beam, and
 in the moving step, the first polishing unit is moved by the first polishing unit holding body while the first polishing unit is moved so as to be along the end face of the substrate by the first polishing unit moving means.   
   
   
       31 . A polishing method for an end face of a substrate by a polishing apparatus according to  claim 17 , comprising:
 a holding step of mounting the substrate on the table unit and fixedly holding the substrate in the reference state by the table unit;   a supporting step of supporting a side portion of the substrate held on the table unit by the substrate side edge portion supporting means of the first polishing unit; and   a moving step of moving, while the polishing grind stone of the first polishing unit is polishing the end face of the side edge portion supported by the substrate side edge portion supporting means, the first polishing unit along the end face being polished by the first polishing unit moving means,   the method further comprising the steps of:   subsequent to the holding step and prior to the moving step, capturing an alignment mark provided on the substrate held on the table unit by the image capturing device;   next, processing image data of the alignment mark by the image capturing device and generating positional data of the alignment mark; and   next, computing a rotation angle with respect to the reference state of the substrate based on the positional data of the alignment mark processed by the image capturing device,   wherein   in the moving step, a movement of the first polishing unit holding body is controlled based on the computed rotation angle such that the first polishing unit moves along the end face of the substrate.   
   
   
       32 . A polishing method for an end face of a substrate by a polishing apparatus according to  claim 20 , comprising:
 a holding step of mounting the substrate on the table unit and fixedly holding the substrate in the reference state by the table unit;   next, a rotating step of rotating the table unit by a predetermined angle with respect to the reference state of the substrate by the table rotating mechanism;   a supporting step of supporting side edge portions facing each other of the substrate held on the table unit by the respective substrate side edge portion supporting means of the first polishing unit and the second polishing unit; and   a moving step of moving, while the polishing grind stones of the first polishing unit and the second polishing unit are polishing the respective end faces of the side edge portions supported by the respective substrate side edge portion supporting means, the first polishing unit and the second polishing unit along the respective end faces being polished by the first polishing unit moving means and the first polishing unit holding body and the second polishing unit moving means and the second polishing unit holding body.   
   
   
       33 . A polishing method according to  claim 32 , wherein the predetermined angle is an angle having a range of 30 degrees to 60 degrees with respect to the reference state. 
   
   
       34 . A polishing method for an end face of a substrate by a polishing apparatus according to  claim 22 , comprising:
 a holding step of mounting the substrate on the table unit and fixedly holding the substrate in the reference state by the table unit; and   a supporting step of supporting side edge portions of the substrate held on the table unit by the respective substrate side edge portion supporting means of the four first polishing unit;   a moving step of moving, while the polishing grind stones of the polishing units are polishing the respective end faces of the side edge portions supported by the respective substrate side edge portion supporting means, the polishing units along the respective end faces being polished by the respective polishing unit moving means.   
   
   
       35 . A polishing method according to  claim 34 , wherein in the moving step, the method computes a polishing amount of each end face based on image data of the respective polishing site obtained from the respective image capturing device and controls the respective polishing unit transfer mechanism.