Method of manufacture of polishing pads having two or more endpoint detection windows

Abstract

A chemical mechanical polishing pad having two or more end point detection windows can be made by providing a structure that includes a polishing layer having a top surface defining a horizontal direction, a bottom surface, and two or more apertures extending from the top surface to the bottom surface wherein each of the two or more apertures has a transparent window located in the aperture, wherein each of the windows has a portion extending outward from the bottom surface of the polishing layer, wherein the two or more apertures are located at select distance from each other, applying a subpad material on the bottom surface and the portion of the windows extending outward from the bottom surface, and revealing the windows by removing a portion of the subpad material and wherein the two or more apertures remain at the select distance from each other.

What is claimed is: 
     
         1 . A method of manufacturing a chemical mechanical polishing pad having two or more end point detection windows comprising:
 providing a structure that includes a polishing layer having a top surface defining a horizontal direction, a bottom surface, and two or more apertures extending from the top surface to the bottom surface wherein each of the two or more apertures has a transparent window located in the aperture, wherein each of the windows has a portion extending outward from the bottom surface of the polishing layer, wherein the two or more apertures are located at select distance from each other,   applying a subpad material on the bottom surface and the portion of the windows extending outward from the bottom surface of the polishing layer and wherein the two or more apertures remain at the select distance from each other,   revealing the windows by removing a portion of the subpad material.   
     
     
         2 . The method of  claim 1  wherein the providing of the structure includes the following:
 providing a mold with a surface and two or more recesses in the surface each recess formed to receive a portion of one of the windows, the recesses being located at the select distance from each other, 
 inserting the windows into the recesses such that a top portion of each the windows extends above the mold surface, 
 forming the polishing layer on the mold surface and around a periphery of the top portion of the windows, and 
 removing the polishing layer with the windows from the mold. 
 
     
     
         3 . The method of  claim 2  wherein in forming the polishing layer a top surface of the windows is covered by a portion of the polishing layer and further comprising revealing the top surface of the windows by removal of a portion of the polishing layer. 
     
     
         4 . The method of  claim 1  wherein the providing of the structure comprises
 forming the two or more apertures in the polishing layer at the select distance from each other, 
 providing the windows for each aperture, each window having a top portion and a flange portion, wherein the top portion has an area in the horizontal direction that is smaller than an area of the flange portion in the horizontal direction such that the second portion forms a rim, 
 applying adhesive to the bottom surface of the polishing layer adjacent the aperture, to the rim of the windows, or both, and 
 inserting into each of the two or more the apertures one of the windows such that the polishing layer surrounds a periphery of the top portion of each of the windows in the horizontal direction. 
 
     
     
         5 . The method of  claim 4  wherein at least a segment the flange portion of the windows forms the portion of the window that extends from the bottom surface of the polishing layer. 
     
     
         6 . The method of  claim 4  wherein the flange portion of the windows is between the top portion of the windows and a bottom portion of the windows, wherein the bottom portion has an area in the horizontal direction that is smaller than the area of the flange portion in the horizontal direction, wherein the bottom portion, or the bottom portion and at least a segment of the flange portion form the portion of the windows extending outward from the bottom surface of the polishing layer and the area of the flange portion in the horizontal direction is larger than the area of the portion of the window extending outward from the bottom surface of the polishing layer. 
     
     
         7 . The method of  claim 1  wherein the subpad material is applied by coating, injection molding, or printing. 
     
     
         8 . The method of  claim 1  wherein an amount of the portion of the window extending outward from the bottom surface of the polishing layer is removed during or after the removing of a portion of the subpad material to form a recessed window. 
     
     
         9 . The method of  claim 1  wherein there are three or more apertures and windows and the select distance between adjacent apertures is the same or different. 
     
     
         10 . The method of  claim 1  wherein the select distance corresponds to a distance of placement of endpoint detectors in a chemical mechanical polishing apparatus having two or more endpoint detectors.