Pad Window Insert

Abstract

A polishing pad includes a polishing layer having a polishing surface, an adhesive layer on a side of the polishing layer opposite the polishing layer, and a solid light-transmitting window extending through and molded to the polishing layer. The solid light-transmitting window has an upper portion with a first lateral dimension and a lower portion with a second lateral dimension that is smaller than the first lateral dimension. A top surface of the solid light-transmitting window coplanar with the polishing surface and a bottom surface of the solid light-transmitting window coplanar with a lower surface of the adhesive layer.

1 . A polishing apparatus, comprising:
 a platen having a planar upper surface, a recess formed in the upper surface, the recess having a bottom surface, and a passage connected to the lower surface of the recess;   a polishing pad comprising a polishing layer a polishing surface, and underside and an aperture therethrough, the aperture having a smaller lateral dimension than the recess, the aperture aligned with the passage; and   a solid light-transmitting window having a first portion positioned at least partially in the aperture in the polishing pad and a second portion positioned at least partially in the recess in the platen, the second portion having a larger lateral dimension than the first portion and extending below the polishing layer, the second portion of the window adhesively attached to an underside of the polishing pad.   
     
     
         2 . The polishing apparatus of  claim 1 , wherein the first portion of the window plugs the aperture in the polishing pad. 
     
     
         3 . The polishing apparatus of  claim 2 , wherein a top surface of the first portion of the window is coplanar with the upper surface of the platen. 
     
     
         4 . The polishing apparatus of  claim 1 , wherein the bottom surface of the recess is parallel with the upper surface of the platen. 
     
     
         5 . The polishing apparatus of  claim 1 , wherein a lower surface of the second portion of window contacts the lower surface of the recess. 
     
     
         6 . The polishing apparatus of  claim 5 , wherein the lower surface of the second portion of window is not adhered to the lower surface of the recess. 
     
     
         7 . The polishing apparatus of  claim 1 , further comprising an adhesive layer spanning the polishing layer. 
     
     
         8 . The polishing apparatus of  claim 7 , wherein the adhesive layer comprises a double-sided adhesive tape. 
     
     
         9 . The polishing apparatus of  claim 7 , wherein the adhesive layer abuts the polishing layer. 
     
     
         10 . The polishing apparatus of  claim 7 , wherein the underside of the polishing pad is adhesively attached to the upper surface of the platen by the adhesive layer. 
     
     
         11 . The polishing apparatus of  claim 10 , wherein a top surface of the second portion of the window is adhesively attached to underside of the polishing pad by the adhesive layer. 
     
     
         12 . The polishing apparatus of  claim 7 , wherein a top surface of the second portion of the window is adhesively attached to underside of the polishing pad. 
     
     
         13 . The polishing apparatus of  claim 1 , wherein the polishing pad consists of the polishing layer. 
     
     
         14 . The polishing apparatus of  claim 1 , wherein the polishing pad consists of the polishing layer and a lower layer that is less compressible than the polishing layer. 
     
     
         15 . The polishing apparatus of  claim 1 , wherein the second portion has a lateral dimension between two and ten times larger than the first portion. 
     
     
         16 . The polishing apparatus of  claim 15 , wherein the second portion has a lateral dimension about 8 times larger than the first portion. 
     
     
         17 . The polishing apparatus of  claim 1 , wherein the second portion of the window laterally fills the recess in the platen. 
     
     
         18 . The polishing apparatus of  claim 1 , wherein the polishing pad has a thickness less than 1 mm. 
     
     
         19 . The polishing apparatus of  claim 1 , further comprising an optical fiber in the passage and positioned to direct or receive light through the first portion of the window. 
     
     
         20 . The polishing apparatus of  claim 19 , wherein the optical fiber is wider than the first portion of the window. 
     
     
         21 . The polishing apparatus of  claim 1 , wherein sides of the recess are sloped and sides of the second portion of the window are sloped. 
     
     
         22 . A method of assembling a window for a polishing apparatus, comprising:
 forming an aperture through a polishing pad, the polishing pad comprising a polishing layer having a polishing surface and underside;   forming a solid light-transmitting window having a first portion and a second portion having a larger lateral dimension than the first portion;   inserting the first portion of the window into the aperture of the pad;   adhering a top surface of the second portion of the window to the underside of the polishing pad; and   positioning the polishing pad and window on a platen such that the second portion of the window fits into a recess in a planar upper surface of the platen and the underside of the polishing pad is adhered to the planar upper surface of the platen.   
     
     
         23 . The method of  claim 22 , wherein a layer of adhesive is formed on the bottom of the polishing layer and a liner covers the adhesive, a portion of the liner is removed around the aperture, and the top surface of the second portion of the window contacts the adhesive in the removed portion of the liner. 
     
     
         24 . The method of  claim 23 , further comprising removing a remainder of the liner before positioning the polishing pad on the platen such that the adhesive adheres the underside of the polishing pad to the planar upper surface of the platen.