Polishing apparatus

Abstract

A polishing apparatus capable of performing multi-stage polishing of a substrate, such as wafer, is disclosed. The polishing apparatus includes: a plurality of polishing tables each for supporting a polishing pad; a plurality of polishing heads each configured to press a substrate against the polishing pad; and a transporting device configured to transport the substrate to at least two of the plurality of polishing heads. The plurality of polishing heads have different structures.

What is claimed is: 
     
         1 . A polishing apparatus comprising:
 a plurality of polishing tables each for supporting a polishing pad;   a plurality of polishing heads each configured to press a substrate against the polishing pad, the plurality of polishing heads having different structures; and   a transporting device configured to transport the substrate to at least two of the plurality of polishing heads.   
     
     
         2 . The polishing apparatus according to  claim 1 , wherein the plurality of polishing heads include:
 at least one uniform-pressure polishing head configured to apply a uniform pressure to the substrate; and   at least one multi-chamber polishing head capable of applying different pressures to the substrate.   
     
     
         3 . The polishing apparatus according to  claim 2 , wherein:
 the at least one uniform-pressure polishing head is at least one of a rigid-body polishing head and a single-chamber polishing head;   the rigid-body polishing head includes
 a rigid body having a flat surface in a circular shape, 
 a substrate holding material in a circular shape attached to the flat surface and configured to press the substrate against the polishing pad, and 
 a guide ring configured to hold the substrate without contact with the polishing pad; and 
   the single-chamber polishing head includes
 a carrier, 
 a plate disposed below the carrier, 
 a circular elastic membrane that forms a single pressure chamber under the plate, and 
 a retainer ring secured to the carrier so as to surround the substrate and configured to press the polishing pad. 
   
     
     
         4 . The polishing apparatus according to  claim 2 , wherein:
 the at least one multi-chamber polishing head is at least one of a first multi-chamber polishing head and a second multi-chamber polishing head;   the first multi-chamber polishing head includes
 a carrier, 
 a plate disposed below the carrier, 
 a circular elastic membrane that forms a plurality of pressure chambers under the plate, and 
 a retainer ring secured to the carrier so as to surround the substrate and configured to press the polishing pad; and 
   the second multi-chamber polishing head includes
 a carrier, 
 a circular elastic membrane that forms a plurality of pressure chambers under the carrier, 
 a retainer ring disposed so as to surround the substrate and configured to press the polishing pad, and 
 an annular elastic membrane provided between the retainer ring and the carrier, an annular pressure chamber being formed in the annular elastic membrane. 
   
     
     
         5 . A polishing apparatus comprising:
 a plurality of polishing tables each for supporting a polishing pad;   a first polishing head having a plurality of pressure chambers each configured to generate a pressure for pressing a substrate against the polishing pad; and   a second polishing head having a plurality of pressure chambers each configured to generate a pressure for pressing the substrate against the polishing pad, an arrangement of the pressure chambers of the second polishing head being different from an arrangement of the pressure chambers of the first polishing head.   
     
     
         6 . The polishing apparatus according to  claim 5 , wherein the pressure chambers of the second polishing head are arranged at positions corresponding to positions of boundaries between the pressure chambers of the first polishing head. 
     
     
         7 . The polishing apparatus according to  claim 5 , wherein at least two of the pressure chambers of the second polishing head are arranged at positions corresponding to a position of one of the pressure chambers of the first polishing head. 
     
     
         8 . A polishing apparatus for polishing a substrate, comprising:
 a first polishing head configured to press a substrate against a first polishing surface to polish a surface of the substrate, the first polishing head having a first elastic membrane which receives a pressure of a fluid to press the substrate against the first polishing surface; and   a second polishing head configured to press a substrate against a second polishing surface to polish a surface of the substrate, the second polishing head having a second elastic membrane which receives a pressure of a fluid to press the substrate against the second polishing surface, and the second elastic membrane having a structure different from that of the first elastic membrane.   
     
     
         9 . The polishing apparatus according to  claim 8 , wherein the second polishing head is configured to further polish the substrate which has been polished by the first polishing head. 
     
     
         10 . The polishing apparatus according to  claim 8 , wherein the second elastic membrane has a hardness different from that of the first elastic membrane. 
     
     
         11 . The polishing apparatus according to  claim 8 , wherein the second elastic membrane has a circumferential wall whose shape is different from that of a circumferential wall of the first elastic membrane. 
     
     
         12 . The polishing apparatus according to  claim 8 , wherein the second elastic membrane has a contact portion which is to be brought into contact with the substrate, the contact portion having a thickness different from that of a contact portion, which is to be brought into contact with the substrate, of the first elastic membrane. 
     
     
         13 . The polishing apparatus according to  claim 8 , wherein the second elastic membrane has a substrate pressing surface whose area is different from that of a substrate pressing surface of the first elastic membrane. 
     
     
         14 . The polishing apparatus according to  claim 8 , wherein the second elastic membrane has a contact portion which is to be brought into contact with the substrate, the contact portion having an edge whose shape is different from that of an edge of a contact portion, which is to be brought into contact with the substrate, of the first elastic membrane. 
     
     
         15 . The polishing apparatus according to  claim 8 , further comprising:
 a third polishing head configured to press a substrate against a third polishing surface to polish a surface of the substrate, the third polishing head having a third elastic membrane which receives a pressure of a fluid to press the substrate against the third polishing surface, the first elastic membrane having the same structure as that of the third elastic membrane; and   a fourth polishing head configured to press a substrate against a fourth polishing surface to polish a surface of the substrate, the fourth polishing head having a fourth elastic membrane which receives a pressure of a fluid to press the substrate against the fourth polishing surface, the second elastic membrane having the same structure as that of the fourth elastic membrane.   
     
     
         16 . A polishing apparatus for polishing a substrate, comprising:
 a first polishing head configured to press a substrate against a first polishing surface to polish a surface of the substrate, the first polishing head having a first retainer ring disposed so as to surround the substrate and configured to press the first polishing surface; and   a second polishing head configured to press a substrate against a second polishing surface to polish a surface of the substrate, the second polishing head having a second retainer ring disposed so as to surround the substrate and configured to press the second polishing surface, and the second retainer ring having a structure different from that of the first retainer ring.   
     
     
         17 . The polishing apparatus according to  claim 16 , wherein the second polishing head is configured to further polish the substrate which has been polished by the first polishing head. 
     
     
         18 . The polishing apparatus according to  claim 16 , wherein:
 the first retainer ring has first grooves each extending from an inner circumferential surface to an outer circumferential surface of the first retainer ring;   the second retainer ring has second grooves each extending from an inner circumferential surface to an outer circumferential surface of the second retainer ring; and   the number of second grooves differs from the number of first grooves.   
     
     
         19 . The polishing apparatus according to  claim 16 , wherein:
 the first retainer ring has first grooves each extending from an inner circumferential surface to an outer circumferential surface of the first retainer ring;   the second retainer ring has second grooves each extending from an inner circumferential surface to an outer circumferential surface of the second retainer ring; and   the second grooves have shape different from that of the first grooves.   
     
     
         20 . The polishing apparatus according to  claim 16 , wherein one of the first retainer ring and the second retainer ring has grooves each extending from an inner circumferential surface to an outer circumferential surface thereof, while the other of the first retainer ring and the second retainer ring has no groove that extends from an inner circumferential surface to an outer circumferential surface thereof. 
     
     
         21 . The polishing apparatus according to  claim 16 , wherein the first retainer ring or the second retainer ring has a tapered or oval edge portion. 
     
     
         22 . The polishing apparatus according to  claim 16 , wherein the second retainer ring has a width different from that of the first retainer ring. 
     
     
         23 . The polishing apparatus according to  claim 16 , wherein the first retainer ring or the second retainer ring comprises an inner retainer ring and an outer retainer ring. 
     
     
         24 . The polishing apparatus according to  claim 16 , wherein the second retainer ring is composed of a material different from that of the first retainer ring. 
     
     
         25 . The polishing apparatus according to  claim 16 , further comprising:
 a third polishing head configured to press a substrate against a third polishing surface to polish a surface of the substrate, the third polishing head having a third retainer ring disposed so as to surround the substrate and configured to press the third polishing surface, the third retainer ring having the same structure as that of the first retainer ring; and   a fourth polishing head configured to press a substrate against a fourth polishing surface to polish a surface of the substrate, the fourth polishing head having a fourth retainer ring disposed so as to surround the substrate and configured to press the fourth polishing surface, and the fourth retainer ring having the same structure as that of the second retainer ring.