Polishing apparatus

Abstract

A turntable with an abrasive cloth mounted thereon and a top ring positioned above the turntable are independently rotatably provided. The top ring holds a workpiece to be polished and presses the workpiece against the abrasive cloth. The turntable and the top ring are rotated to polish the surface of the workpiece to a flat mirror finish on the abrasive cloth. A rotatable brush pressed against the abrasive cloth is rotated about an axis substantially perpendicularly to the plane of the abrasive cloth, and oscillated substantially radially between radially inner and outer positions over the abrasive cloth. A cleaning solution is sprayed from a nozzle onto the abrasive cloth. The turntable has a bank along an outer circumferential edge thereto for preventing a protective solution, which is supplied to the abrasive cloth to keep the abrasive cloth wet and prevent it, from flowing off the turntable when the turntable is stationary.

What is claimed is:  
     
       1. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       a turntable with an abrasive cloth mounted on an upper surface thereof;  
       a top ring positioned above said turntable for supporting the workpiece to be polished and pressing the workpiece against said abrasive cloth; 
       a rotatable brush, being supported by an arm, facing said abrasive cloth;  
       first actuating means for rotating said rotatable brush about an axis substantially perpendicularly to the plane of said abrasive cloth;  
       second actuating means for oscillating said rotatable brush substantially radially between radially inner and outer positions over said abrasive cloth; and  
       a nozzle for supplying a cleaning solution onto said abrasive cloth. ; and  
       
         a hydraulic cylinder capable of moving said rotatable brush upward and downward,  
       
       
         wherein said first actuating means includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable brush;  
       
       
         wherein said second actuating means includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable brush being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable brush. 
       
     
     
       2. The polishing apparatus according to  claim 1 , wherein said second actuating means comprises an angularly movable arm supporting said brush on one end thereof and a swinging mechanism for oscillating said arm. 
     
     
       3. The polishing apparatus according to  claim 1 , further comprising means for vertically moving said rotatable brush toward and away from said abrasive cloth. 
     
     
       4. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       a turntable with an abrasive cloth mounted on an upper surface thereof;  
       a top ring positioned above said turntable for supporting the workpiece to be polished and pressing the workpiece against said abrasive cloth; and  
       a bank provided on said turntable along an outer circumferential edge thereof for preventing a protective solution, which is supplied to said abrasive cloth to keep the abrasive cloth from drying when said turntable is held at rest, from flowing off said turntable, said bank having a slanted surface inclined radially inwardly of said turntable for allowing the protective solution to be scattered away from said turntable over said slanted surface under centrifugal forces when said turntable is rotated.  
     
     
       5. The polishing apparatus according to  claim 4 , further comprising an annular solution retainer fixedly mounted on said turntable along said outer circumferential edge of the turntable, said bank being integrally formed on said annular solution retainer. 
     
     
       6. The polishing apparatus according to  claim 4 , wherein said bank is integrally formed on said turntable. 
     
     
       7. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       a turntable with an abrasive cloth mounted on an upper surface thereof;  
       a top ring positioned above said turntable for supporting the workpiece to be polished and pressing the workpiece against said abrasive cloth;  
       a rotatable brush facing said abrasive cloth;  
       first actuating means for rotating said rotatable brush about an axis substantially perpendicular to the plane of said abrasive cloth;  
       second actuating means for reciprocally moving said rotatable brush substantially radially between radially inner and outer positions over said abrasive cloth;  
       a nozzle for supplying a cleaning solution onto said abrasive cloth; and  
       a bank provided on said turntable along an outer circumferential edge thereof for preventing a protective solution, which is supplied to said abrasive cloth to keep the abrasive cloth from drying when said turntable is held at rest, from flowing off said turntable, said bank having a slanted surface inclined downwardly in a radially inward direction of said turntable for allowing the protective solution to be scattered away from said turntable over said slanted surface under centrifugal forces when said turntable is rotated.  
     
     
       8. The polishing apparatus according to  claim 7 , wherein said second actuating means comprises an angularly movable arm supporting said brush on one end thereof and a swinging mechanism for reciprocally swinging said arm. 
     
     
       9. The polishing apparatus according to  claim 7 , further comprising means for vertically moving said rotatable brush toward and away from said abrasive cloth. 
     
     
       10. The polishing apparatus according to  claim 7 , further comprising an annular solution retainer fixedly mounted on said turntable along said outer circumferential edge of the turntable, said bank being integrally formed on said annular solution retainer. 
     
     
       11. The polishing apparatus according to  claim 7 , wherein said bank is integrally formed on said turntable. 
     
     
       12. A polishing apparatus for polishing a workpiece, comprising: 
       
         a rotatable turntable having a substantially circular abrasive cloth mounted on an upper surface thereof and a central axis thereof;  
       
       
         a rotatable substantially circular treating means being supported by an arm for treating said upper surface of said abrasive cloth, a rotatable surface of said rotatable circular treating means being parallel to that of said circular abrasive cloth;  
       
       
         an oscillatable arm means for holding said rotatable circular treating means over said upper surface of said abrasive cloth;  
       
       
         a first actuating means for rotating said rotatable circular treating means about an axis thereof substantially perpendicular to said rotatable surface of said circular abrasive cloth;  
       
       
         a second actuating means for oscillating said rotatable circular treating means substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being said axis of said rotatable turntable and said second position being an outside periphery thereof,  
       
       
         a hydraulic cylinder capable of moving said rotatable circular treating means upward and downward,  
       
       
         wherein said first actuating means includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable substantially circular treating means,  
       
       
         wherein said second actuating means includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable circular treating means being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable circular treating means. 
       
     
     
       13. A process for treating a surface of a circular abrasive cloth on a turntable of a polishing apparatus, said process comprising the steps of: 
       
         rotating a rotatable treating means as well as said circular abrasive cloth on said turntable, said rotatable treating means being supported by an arm and being rotated by a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable treating means;  
       
       
         moving said rotatable treating means upward and downward with a hydraulic cylinder  
       
       
         pressing said rotatable treating means against said circular abrasive cloth of said turntable; and  
       
       
         oscillating said arm of said rotatable treating means substantially radially towards a first position and toward a second position on said circular abrasive cloth, said first position being an axis of said turntable and said second position being an outside periphery thereof, said oscillating said arm of said rotatable treating means being conducted by rotating said shaft supporting said arm with a second motor,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable treating means being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable treating means. 
       
     
     
       14. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       
         a turntable with an abrasive cloth mounted on an upper surface thereof;  
       
       
         a rotatable brush, being supported by an arm, facing said abrasive cloth;  
       
       
         first actuator for rotating said rotatable brush about an axis substantially perpendicularly to the plane of said abrasive cloth;  
       
       
         second actuator for oscillating said rotatable brush substantially radially between radially inner and outer positions over said abrasive cloth;  
       
       
         a nozzle for supplying a cleaning solution onto said abrasive cloth; and  
       
       
         a hydraulic cylinder capable of moving said rotatable brush upward and downward,  
       
       
         wherein said first actuator includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable brush,  
       
       
         wherein said second actuator includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable brush being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable brush. 
       
     
     
       15. A polishing apparatus for polishing a workpiece, comprising: 
       
         a rotatable turntable having a substantially circular abrasive cloth mounted on an upper surface thereof and a central axis thereof;  
       
       
         a rotatable substantially circular treating tool, being supported by an arm, for treating said upper surface of said abrasive cloth, a rotatable surface of said rotatable circular treating tool being parallel to that of said circular abrasive cloth;  
       
       
         an oscillatable arm for holding said rotatable circular treating tool over said upper surface of said abrasive cloth;  
       
       
         a first actuator for rotating said rotatable circular treating tool about an axis thereof substantially perpendicular to said rotatable surface of said circular abrasive cloth;  
       
       
         a second actuator for oscillating said rotatable circular treating tool substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being said axis of said rotatable turntable and said second position being an outside periphery thereof; and  
       
       
         a hydraulic cylinder capable of moving said rotatable circular treating tool upward and downward,  
       
       
         wherein said first actuator includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable substantially circular treating tool,  
       
       
         wherein said second actuator includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable circular treating tool being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable circular treating tool. 
       
     
     
       16. A process for treating a surface of a circular abrasive cloth on a turntable of a polishing apparatus, said process comprising the steps of: 
       
         rotating a rotatable treating tool as well as said circular abrasive cloth on said turntable, said rotatable treating tool being supported by an arm and being rotated by a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable treating tool;  
       
       
         moving said rotatable treating tool upward and downward with a hydraulic cylinder;  
       
       
         pressing said rotatable treating tool against said circular abrasive cloth of said turntable; and  
       
       
         oscillating said arm of said rotatable treating tool substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being an axis of said turntable and said second position being an outside periphery thereof, said oscillating said arm of said rotatable treating tool being conducted by rotating said shaft supporting said arm with a second motor,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable treating tool being located at said second end,  
       
       
         wherein a first distance between said first motor and said arm supporting shaft is, along a plane along which said arm extends, less than a second distance between said arm supporting shaft and said rotatable treating tool. 
       
     
     
       17. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       
         a turntable having a polishing surface on an upper surface thereof;  
       
       
         a top ring for supporting the workpiece to be polished and pressing the workpiece against said polishing surface; and  
       
       
         a bank disposed on outer circumferential edge of said turntable for preventing a protective solution, which is supplied to said polishing surface to keep said polishing surface from drying when said turntable is held at rest, from flowing off said turntable. 
       
     
     
       18. A polishing apparatus according to  claim 17 , wherein said protective solution is pure water. 
     
     
       19. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       
         a turntable with an abrasive cloth mounted on an upper surface thereof;  
       
       
         a rotatable brush, being supported by an arm, facing said abrasive cloth;  
       
       
         first actuating means for rotating said rotatable brush about an axis substantially perpendicularly to the plane of said abrasive cloth;  
       
       
         second actuating means for oscillating said rotatable brush substantially radially between radially inner and outer positions over said abrasive cloth;  
       
       
         a nozzle for supplying a cleaning solution onto said abrasive cloth; and  
       
       
         a hydraulic cylinder capable of moving said rotatable brush upward and downward,  
       
       
         wherein said first actuating means includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable brush,  
       
       
         wherein said second actuating means includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable brush being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable brush. 
       
     
     
       20. A polishing apparatus for polishing a workpiece, comprising: 
       
         a rotatable turntable having a substantially circular abrasive cloth mounted on an upper surface thereof and a central axis thereof;  
       
       
         a rotatable substantially circular treating means being supported by an arm for treating said upper surface of said abrasive cloth, a rotatable surface of said rotatable circular treating means being parallel to that of said circular abrasive cloth;  
       
       
         an oscillatable arm means for holding said rotatable circular treating means over said upper surface of said abrasive cloth;  
       
       
         a first actuating means for rotating said rotatable circular treating means about an axis thereof substantially perpendicular to said rotatable surface of said circular abrasive cloth;  
       
       
         a second actuating means for oscillating said rotatable circular treating means substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being said axis of said rotatable turntable and said second position being an outside periphery thereof,  
       
       
         a hydraulic cylinder capable of moving said rotatable circular treating means upward and downward,  
       
       
         wherein said first actuating means includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable substantially circular treating means,  
       
       
         wherein said second actuating means includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable circular treating means being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable circular treating means. 
       
     
     
       21. A process for treating a surface of a circular abrasive cloth on a turntable of a polishing apparatus, said process comprising the steps of: 
       
         rotating a rotatable treating means as well as said circular abrasive cloth on said turntable, said rotatable treating means being supported by an arm and being rotated by a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable treating means;  
       
       
         moving said rotatable treating means upward and downward with a hydraulic cylinder  
       
       
         pressing said rotatable treating means against said circular abrasive cloth of said turntable; and  
       
       
         oscillating said arm of said rotatable treating means substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being an axis of said turntable and said second position being an outside periphery thereof, said oscillating said arm of said rotatable treating means being conducted by rotating said shaft supporting said arm with a second motor,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable treating means being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable treating means. 
       
     
     
       22. A polishing apparatus for polishing a surface of a workpiece, comprising: 
       
         a turntable with an abrasive cloth mounted on an upper surface thereof;  
       
       
         a rotatable brush, being supported by an arm, facing said abrasive cloth;  
       
       
         first actuator for rotating said rotatable brush about an axis substantially perpendicularly to the plane of said abrasive cloth;  
       
       
         second actuator for oscillating said rotatable brush substantially radially between radially inner and outer positions over said abrasive cloth;  
       
       
         a nozzle for supplying a cleaning solution onto said abrasive cloth; and  
       
       
         a hydraulic cylinder capable of moving said rotatable brush upward and downward,  
       
       
         wherein said first actuator includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable brush,  
       
       
         wherein said second actuator includes a second motor for rotating said shaft supporting said arm, wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable brush being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable brush. 
       
     
     
       23. A polishing apparatus for polishing a workpiece, comprising: 
       
         a rotatable turntable having a substantially circular abrasive cloth mounted on an upper surface thereof and a central axis thereof;  
       
       
         a rotatable substantially circular treating tool, being supported by an arm, for treating said upper surface of said abrasive cloth, a rotatable surface of said rotatable circular treating tool being parallel to that of said circular abrasive cloth;  
       
       
         an oscillatable arm for holding said rotatable circular treating tool over said upper surface of said abrasive cloth;  
       
       
         a first actuator for rotating said rotatable circular treating tool about an axis thereof substantially perpendicular to said rotatable surface of said circular abrasive cloth;  
       
       
         a second actuator for oscillating said rotatable circular treating tool substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being said axis of said rotatable turntable and said second position being an outside periphery thereof; and  
       
       
         a hydraulic cylinder capable of moving said rotatable circular treating tool upward and downward,  
       
       
         wherein said first actuator includes a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable substantially circular treating tool,  
       
       
         wherein said second actuator includes a second motor for rotating said shaft supporting said arm,  
       
       
         wherein said arm has a first end and a second end, said first motor being located at said first end, while said rotatable circular treating tool being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable circular treating tool. 
       
     
     
       24. A process for treating a surface of a circular abrasive cloth on a turntable of a polishing apparatus, said process comprising the steps of: 
       
         rotating a rotatable treating tool as well as said circular abrasive cloth on said turntable, said rotatable treating tool being supported by an arm and being rotated by a first motor located in the vicinity of a shaft supporting said arm, and an endless member for transmitting rotation of said first motor to said rotatable treating tool;  
       
       
         moving said rotatable treating tool upward and downward with a hydraulic cylinder;  
       
       
         pressing said rotatable treating tool against said circular abrasive cloth of said turntable; and  
       
       
         oscillating said arm of said rotatable treating tool substantially radially toward a first position and toward a second position on said circular abrasive cloth, said first position being an axis of said turntable and said second position being an outside periphery thereof, said oscillating said arm of said rotatable treating tool being conducted by rotating said shaft supporting said arm with a second motor,  
       
       
         wherein said arm has a first end and second end, said first motor being located at said first end, while said rotatable treating tool being located at said second end,  
       
       
         wherein said arm supporting shaft supports said arm along another axis,  
       
       
         wherein a first distance between said first motor and said another axis is, along a plane along which said arm extends, less than a second distance between said another axis and said rotatable treating tool.