Method for manufacturing polishing head and polishing apparatus

Abstract

A method for manufacturing a polishing head having an annular rigid ring; a rubber film bonded to the rigid ring with uniform tension; a mid plate joined to the rigid ring, forming a space together with the rubber film and the rigid ring; and a mechanism for changing pressure of the space, the method including performing a tensile test on the rubber film according to JIS K6251 before bonding the rubber film to the rigid ring, and selecting the rubber film having a value of 10 MPa or less of an inclination obtained by a linear approximation of a stress-strain curve within a strain value of 5%; and bonding the selected rubber film having a value of 10 MPa or less of the inclination to the rigid ring to manufacture the polishing head.

1 . A method for manufacturing a polishing head having at least: an annular rigid ring; a rubber film bonded to the rigid ring with a uniform tension; a mid plate joined to the rigid ring, the mid plate forming a space together with the rubber film and the rigid ring; and a pressure adjustment mechanism for changing pressure of the space, the polishing head holding a back surface of a workpiece on a lower face portion of the rubber film and polishing the workpiece by bringing a surface of the workpiece into sliding contact with a polishing pad attached onto a turn table, the method comprising the steps of:
 performing a tensile test on the rubber film according to JIS K6251 before bonding the rubber film to the rigid ring, and selecting the rubber film having a value of 10 MPa or less of an inclination obtained by a linear approximation of a stress-strain curve within a strain value of 5%; and   bonding the selected rubber film having a value of 10 MPa or less of the inclination to the rigid ring to manufacture the polishing head.   
     
     
         2 . The method for manufacturing a polishing head according to  claim 1 , wherein the workpiece to be held is a silicon single crystal wafer having a diameter of 300 mm or more. 
     
     
         3 . A polishing apparatus having at least a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and a polishing head for holding a workpiece, the polishing apparatus polishing a surface of the workpiece while holding a back surface of the workpiece with the polishing head, wherein
 the polishing head has at least: an annular rigid ring; a rubber film bonded to the rigid ring with a uniform tension; a mid plate joined to the rigid ring, the mid plate forming a space together with the rubber film and the rigid ring; and a pressure adjustment mechanism for changing pressure of the space,   the rubber film is formed by using a rubber material having a value of 10 MPa or less of an inclination obtained by a linear approximation of a stress-strain curve within a strain value of 5%, the stress-strain curve being obtained as a result of performing a tensile test on the rubber film according to JIS K6251,   the polishing pad has a young's modulus of 3.5 MPa or less,   the workpiece is polished by bringing a surface of the workpiece into sliding contact with the polishing pad attached onto the turn table with the pressure of the space controlled by the pressure adjustment mechanism.   
     
     
         4 . The polishing apparatus according to  claim 3 , wherein the workpiece to be polished is a silicon single crystal wafer having a diameter of 300 mm or more.