Endpoint window with controlled texture surface

Abstract

A chemical mechanical polishing pad window having a controlled texture surface comprising repeated patterned features. The window results in an improved endpoint detection and in situ rate monitoring by providing consistent values of the ISRMmax-min characteristic over the lifetime of a CMP pad. Also provided is a chemical mechanical polishing pad with the inventive window.

1 . A window for a chemical mechanical planarization (CMP) pad, the window comprising a material transmissive to light, wherein a first surface of the window has a controlled texture surface comprising repeated patterned features. 
     
     
         2 . The window of  claim 1 , wherein the first surface corresponds to a bottom surface of the CMP pad which does not contact a substrate being planarized during a CMP process using the CMP pad. 
     
     
         3 . The window of  claim 1 , wherein the repeated patterned features are configured to diffuse light passing through the window. 
     
     
         4 . The window of  claim 1 , wherein the repeated patterned features comprise regularly spaced raised features. 
     
     
         5 . The window of  claim 4 , wherein the repeated patterned features comprise a crosshatch pattern. 
     
     
         6 . The window of  claim 4 , wherein the repeated patterned features comprise rounded ridges. 
     
     
         7 . The window of  claim 5 , wherein the rounded ridges are randomly roughened. 
     
     
         8 . The window of  claim 2 , wherein a second surface opposite the first surface corresponds to a top surface, the top surface is capable of contacting a substrate being planarized during a CMP process using the CMP pad, wherein the top surface has a roughened texture corresponding to an average surface roughness in a range from about 1 to about 50 micrometers. 
     
     
         9 . The window of  claim 1 , wherein:
 the window has a width and length that is less than the width, wherein the width and the length characterize physical dimensions of the window; and   the repeated patterned features comprise:
 a first set of regularly spaced raised features parallel to a direction of the width of the window; and 
 a second set of regularly spaced raised lines at an angle relative to the first set of regularly spaced raised features. 
   
     
     
         10 . The window of  claim 1 , wherein:
 the window has a width and length that is less than the width wherein the width and the length characterize physical dimensions of the window; and   the repeated patterned features comprise a crosshatch texture comprising:
 a first set of regularly spaced features in the first surface at a first angle relative to a direction of the width of the window; and 
 a second set of regularly spaced features in the first surface at a second angle relative to the first set of lines, wherein the first angle is different than the second angle. 
   
     
     
         11 . A chemical mechanical planarization (CMP) pad comprising:
 a top surface which contacts a substrate being planarized during a CMP process using the CMP pad;   a bottom surface opposite the top surface; and   a window that allows light to pass between a top side of the CMP pad associated with the top surface and a bottom side of the CMP pad associated with the bottom surface, the window comprising a material transmissive to light, wherein a first surface of the window has repeated patterned features.   
     
     
         12 . The CMP pad of  claim 11 , wherein the first surface of the window faces the same direction as the bottom surface of the CMP pad which does not contact the substrate being planarized during a CMP process using the CMP pad. 
     
     
         13 . The CMP pad of  claim 11 , wherein the repeated patterned features are configured to diffuse light passing through the window. 
     
     
         14 . The CMP pad of  claim 11 , wherein the repeated patterned features comprise regularly spaced raised features. 
     
     
         15 . The CMP pad of  claim 11 , wherein the repeated patterned features comprise a crosshatch pattern. 
     
     
         16 . The CMP pad of  claim 11 , wherein the repeated patterned features comprise rounded ridges. 
     
     
         17 . The CMP pad of  claim 16 , wherein the rounded ridges are randomly roughened. 
     
     
         18 . The CMP pad of  claim 11 , wherein a second surface opposite the first surface corresponds to a top surface, the top surface is capable of contacting a substrate being planarized during a CMP process using the CMP pad, wherein the top surface has a roughened texture corresponding to an average surface roughness in a range from about 1 to about 50 micrometers. 
     
     
         19 . The CMP pad of  claim 11 , wherein:
 the window has a width and length that is less than the width, wherein the width and the length characterize physical dimensions of the window; and   the repeated patterned features comprise:
 a first set of regularly spaced raised features parallel to a direction of the width of the window; and 
 a second set of regularly spaced raised lines at an angle relative to the first set of regularly spaced raised features. 
   
     
     
         20 . The CMP pad of  claim 11 , wherein:
 the window has a width and length that is less than the width wherein the width and the length characterize physical dimensions of the window; and   the repeated patterned features comprise a crosshatch texture comprising:
 a first set of regularly spaced features in the first surface at a first angle relative to a direction of the width of the window; and 
 a second set of regularly spaced features in the first surface at a second angle relative to the first set of lines, wherein the first angle is different than the second angle. 
   a window as disclosed herein.