Polishing apparatus

Abstract

The polishing apparatus is capable of improving accuracy of polishing a work. The work is pressed onto a polishing cloth, with an elastic sheet, by a pressing force generated by second pressing means and applied to a carrier and inner pressure of a first fluid chamber generated by a fluid supplied thereto, so as to polish the work. The fluid, which has been downwardly supplied into the first fluid chamber, horizontally flows outward in the first fluid chamber, collides with a side wall of a concave part of a board-shaped member and flows upward, and then the fluid is discharged outside from a fluid outlet, thereby a fluid feeding member follows movement of the elastic sheet and maintains parallel to the elastic sheet, and the fluid feeding member is centered in the first fluid chamber.

1 . A polishing apparatus for polishing a surface of a work, comprising:
 a polishing plate having a surface on which a polishing cloth is adhered;   a polishing head for pressing the work onto the polishing cloth; and   a driving mechanism for relatively moving the polishing head with respect to the polishing plate,   wherein the polishing head includes:
 a main body section; 
 a board-shaped member having a concave part whose open end is aimed downward, the board-shaped member being suspended from the main body section and movable in the vertical direction; 
 a carrier being located in the concave part of the board-shaped member, being supported by the board-shaped member and being capable of inclining, in a state where a prescribed gap is formed between an outer circumferential face of the carrier and a side wall of the concave part, with respect to the horizontal plane, the carrier having a fluid feeding member which has a plurality of spraying ports from which a fluid is sprayed downward; 
 fluid supplying means for supplying the fluid to the carrier so as to spray the fluid downward from the fluid feeding member; 
 an elastic sheet being provided to the board-shaped member and covering a lower side of the fluid feeding member so as to form a first fluid chamber, the elastic sheet being capable of holding the work on a lower surface thereof; 
 a ring-shaped member being provided to an outer edge part of the lower surface of the elastic sheet, the ring-shaped member being capable of enclosing the work held on the lower surface of the elastic sheet; 
 first pressing means for pressing the board-shaped member downward so as to press the ring-shaped member onto the polishing cloth with the elastic sheet; 
 second pressing means for pressing the carrier downward; and 
 a fluid outlet for discharging the fluid from the first fluid chamber, the fluid outlet being formed, in the board-shaped member, at a position higher than a lower surface of the fluid feeding member, and 
   wherein the work is pressed onto the polishing cloth, with the elastic sheet, by a pressing force generated by the second pressing means and applied to the carrier and inner pressure of the first fluid chamber generated by the fluid supplied to the first fluid chamber, so as to polish the work, and   the fluid, which has been downwardly supplied into the first fluid chamber, horizontally flows outward in the first fluid chamber, collides with the side wall of the concave part and flows upward, and then the fluid is discharged outside from the fluid outlet, thereby the fluid feeding member follows movement of the elastic sheet and maintains parallel to the elastic sheet, and the fluid feeding member is centered in the first fluid chamber.   
     
     
         2 . The polishing apparatus according to  claim 1 ,
 wherein the carrier is supported by the board-shaped member with a diaphragm and capable of inclining in the state where the prescribed gap is formed between the outer circumferential face of the carrier and the side wall of the concave part, and   the second pressing means includes:
 a second fluid chamber being formed, by the diaphragm, between the carrier and the board-shaped member; and 
 second fluid supplying means for supplying the fluid to the second fluid chamber. 
   
     
     
         3 . The polishing apparatus according to  claim 1 ,
 wherein the board-shaped member is suspended, by a diaphragm, from the main body section and movable in the vertical direction, and   the first pressing means includes:
 a third fluid chamber being formed, by the diaphragm, between the board-shaped member and the main body section; and 
 third fluid supplying means for supplying the fluid to the third fluid chamber. 
   
     
     
         4 . The polishing apparatus according to  claim 2 ,
 wherein the board-shaped member is suspended, by a diaphragm, from the main body section and movable in the vertical direction, and   the first pressing means includes:
 a third fluid chamber being formed, by the diaphragm, between the board-shaped member and the main body section; and 
 third fluid supplying means for supplying the fluid to the third fluid chamber. 
   
     
     
         5 . The polishing apparatus according to  claim 1 ,
 wherein a discharge pipe is connected to the fluid outlet, a relief valve is provided to the discharge pipe, and inner pressure of the first fluid chamber is maintained, at prescribed pressure, by the relief valve.   
     
     
         6 . The polishing apparatus according to  claim 2 ,
 wherein a discharge pipe is connected to the fluid outlet, a relief valve is provided to the discharge pipe, and inner pressure of the first fluid chamber is maintained, at prescribed pressure, by the relief valve.   
     
     
         7 . The polishing apparatus according to  claim 3 ,
 wherein a discharge pipe is connected to the fluid outlet, a relief valve is provided to the discharge pipe, and inner pressure of the first fluid chamber is maintained, at prescribed pressure, by the relief valve.   
     
     
         8 . The polishing apparatus according to  claim 5 ,
 wherein the fluid discharged from the discharge pipe is collected and reused.   
     
     
         9 . The polishing apparatus according to  claim 1 ,
 wherein the pressing force, which is applied to the work via the elastic sheet, is different in a plurality of coaxial zones of the work, and flow volume of the fluid toward the first fluid chamber is set for each of the coaxial zones.   
     
     
         10 . The polishing apparatus according to  claim 1 ,
 wherein the fluid fed into the first fluid chamber is air.   
     
     
         11 . The polishing apparatus according to  claim 1 ,
 wherein the elastic sheet is a two-layered sheet constituted by a sheet-shaped member and a holding member provided under the sheet-shaped member.