Shear sensors and uses thereof

Abstract

The present invention relates to shear sensors. In particular, the present invention relates to deformable sensors for measurement of shear forces during chemical mechanical polishing.

1 . A system, comprising:
 a) at least one deformable sensor, wherein said sensor is deformed under shear stress arising during chemical mechanical polishing;   b) an apparatus for chemical mechanical processing (CMP), wherein said apparatus is in active communication with said sensor; and   c) a detection device for detection of deformation of said sensor.   
     
     
         2 . The system of  claim 1 , wherein said sensor is composed of poly-dimethyl-siloxane (PDMS). 
     
     
         3 . The system of  claim 2 , wherein said sensor comprises a plurality of posts. 
     
     
         4 . The system of  claim 3 , wherein said post is coated with a metal. 
     
     
         5 . The system of  claim 4 , wherein said metal is chromium. 
     
     
         6 . The system of  claim 3 , wherein said post has diameter of at least 1 μm. 
     
     
         7 . The system of  claim 3 , wherein said post has a diameter of approximately 30 μm to 100 μm. 
     
     
         8 . The system of  claim 3 , wherein said post has a height:diameter ratio of less than approximately 4:1. 
     
     
         9 . The system of  claim 3 , wherein said sensor further comprises molded markings. 
     
     
         10 . The system of  claim 1 , wherein said system comprises an array of said sensors. 
     
     
         11 . The system of  claim 1 , wherein said sensors are affixed to a polishing wafer. 
     
     
         12 . The system of  claim 11 , wherein said polishing wafer is affixed to said CMP apparatus using an aluminum mating plate. 
     
     
         13 . The system of  claim 12 , wherein said aluminum mating plate comprises a plurality of viewing windows. 
     
     
         14 . The system of  claim 1 , wherein said sensor comprises a floating element supported by a flexure. 
     
     
         15 . The system of  claim 14 , wherein said sensor is composed of a material selected from the group consisting of silicon and a thick metal film. 
     
     
         16 . The system of  claim 15 , wherein said thick metal film is selected from the group consisting of copper and nickel. 
     
     
         17 . The system of  claim 15 , wherein said floating element is circular. 
     
     
         18 . The system of  claim 1 , wherein the detection device comprises a light source, a microscope, and a CCD camera. 
     
     
         19 . The system of  claim 18 , wherein said camera is a high speed camera. 
     
     
         20 . The system of  claim 18 , wherein said light source is a fiber optic light source. 
     
     
         21 . A method, comprising contacting at least one deformable sensor, wherein said sensor is deformed under shear stress arising during chemical mechanical polishing, with an apparatus for chemical mechanical processing (CMP) under conditions such that said sensor is deformed. 
     
     
         22 . The method of  claim 21 , further comprising the step of calculating shear forces on said sensor based on said deformation of said sensor. 
     
     
         23 . The method of  claim 22 , wherein said shear forces are calculated using a computer processor and computer software.