Using sacrificial material in additive manufacturing of polishing pads

Abstract

A method of fabricating a polishing pad using an additive manufacturing system includes depositing a first set successive layers by droplet ejection to form a. Depositing the successive layers includes dispensing a polishing pad precursor to first regions corresponding to partitions of the polishing pad and dispensing a sacrificial material to second regions corresponding to grooves of the polishing pad. Removing the sacrificial material provides the polishing pad with a polishing surface that has the partitions separated by the grooves.

What is claimed is: 
     
         1 . A method of fabricating a polishing pad using an additive manufacturing system, the method comprising:
 depositing a first plurality of successive layers by droplet ejection onto a support, the first plurality of successive layers corresponding to a lower portion of the polishing pad;   depositing onto the lower portion of the polishing pad a second plurality of successive layers by droplet ejection, wherein depositing the second plurality of successive layers includes
 dispensing by droplet ejection a polishing pad precursor to first regions corresponding to partitions of the polishing pad, and 
 dispensing a sacrificial material to second regions that abut the first regions to form walls that line the vertical surfaces of the partitions, wherein gaps between adjacent partitions correspond to grooves in the polishing pad, 
 wherein the first plurality of successive layers and the second plurality of successive layers providing a body and the first plurality of successive layers span the partitions and the grooves between the partitions; and 
   removing the body from the support and removing the sacrificial material from the body to provide the polishing pad comprising the polishing surface having the partitions separated by the grooves.   
     
     
         2 . The method of  claim 1 , wherein dispensing the sacrificial material comprises droplet ejection. 
     
     
         3 . The method of  claim 1 , comprising curing the polishing pad precursor. 
     
     
         4 . The method of  claim 3 , comprising curing the sacrificial material. 
     
     
         5 . The method of  claim 4 , wherein the polishing pad precursor comprises a first polymer precursor and the sacrificial material comprises a second polymer precursor of different composition. 
     
     
         6 . The method of  claim 1 , wherein depositing the first plurality of successive layers comprises dispensing the polishing pad precursor. 
     
     
         7 . The method of  claim 1 , wherein removing the sacrificial material comprises etching. 
     
     
         8 . The method of  claim 1 , comprising curing the polishing pad precursor. 
     
     
         9 . The method of  claim 8 , wherein curing comprises directing UV light onto the polishing pad precursor. 
     
     
         10 . The method of  claim 8 , comprising curing the sacrificial material. 
     
     
         11 . The method of  claim 10 , wherein the sacrificial materials and polishing pad precursor are cured with different wavelengths of light. 
     
     
         12 . The method of  claim 10 , wherein the sacrificial materials and polishing pad precursor are cured with different intensities of light. 
     
     
         13 . The method of  claim 1 , wherein depositing a layer from the second plurality of successive layers includes dispensing the polishing pad precursor and the sacrificial material with a single pass of two ejectors. 
     
     
         14 . The method of  claim 1 , wherein removing the sacrificial material comprises separating a body of the polishing pad from the sacrificial material.