Micromachining by chemical mechanical polishing

Abstract

Methods of micromachining structures on substrates using chemical mechanical polishing techniques.

1 . A method for micromachining a structure, said method comprising selectively removing at least a portion of the structure by chemical mechanical polishing, wherein the structure thus formed is at least partially non-planar and wherein the structure includes a highest point and a lowest point, and has a height differential between the highest point and the lowest point of 0.5 microns or greater.  
   
   
       2 . The method of  claim 1  wherein the structure is formed on an essentially planar substrate.  
   
   
       3 . The method of  claim 1  wherein said chemical mechanical polishing step is conducted using a chemical mechanical polishing apparatus that includes a polishing pad.  
   
   
       4 . The method of  claim 3  wherein said removal is by a combination of chemical etch and mechanical polishing.  
   
   
       5 . The method of  claim 4  wherein said mechanical polishing is controlled by varying at least one characteristic of the polishing pad.  
   
   
       6 . The method of  claim 5  wherein said characteristic of the polishing pad is stiffness.  
   
   
       7 . The method of  claim 6  wherein said stiffness is manipulated by downforce on the pad, rotational velocity of the pad, acceleration velocity of the pad, local curvature of the pad, or combinations thereof.  
   
   
       8 . The method of  claim 1  wherein a concave structure is formed.  
   
   
       9 . The method of  claim 1  wherein a convex structure is formed.  
   
   
       10 . The method of  claim 1  wherein a rounded structure is formed.  
   
   
       11 . The method of  claim 7  wherein local curvature on the pad is provided be by pre-shaped asperities.  
   
   
       12 . The method of  claim 7  wherein local curvature on the pad is provided by bumps under the pad.  
   
   
       13 . (canceled)  
   
   
       14 . The method of  claim 1  wherein the height differential between the highest point and the lowest point is 1 micron or greater.  
   
   
       15 . The method of  claim 1  wherein the height differential between the highest point and the lowest point is 2 microns or greater.  
   
   
       16 . A partially non-planar structure fabricated by the method of  claim 1 .  
   
   
       17 . A microlens array fabricated by the method of  claim 1 .  
   
   
       18 . An optical fiber array connector fabricated by the method of  claim 1.