Polishing pads having selectively arranged porosity

Abstract

Polishing pads having discrete and selectively arranged regions of varying porosity within a continuous phase of polymer material are provided herein. In one embodiment a polishing pad features a plurality of polishing elements each comprising a polishing surface and sidewalls extending downwardly from the polishing surface to define a plurality of channels disposed between the polishing elements, wherein one or more of the polishing elements is formed of a continuous phase of polymer material having one or more first regions comprising a first porosity and a second region comprising a second porosity, wherein the second porosity is less than the first porosity.

1 . A method of forming a polishing pad, comprising:
 (a) dispensing droplets of a first pre-polymer composition and droplets of a sacrificial material composition onto a surface of a previously formed print layer according to a predetermined droplet dispense pattern; and   (b) at least partially curing the dispensed droplets of the first pre-polymer composition to form a print layer comprising at least portions of a polymer pad material having one or more first regions comprising a first porosity and one or more second regions comprising a second porosity disposed adjacent to the one or more first regions, wherein porosity is a volume of void-space or sacrificial material as a percentage of total volume in the respective first and second regions and the second porosity is less than the first porosity; and   (c) sequentially repeating (a) and (b).   
     
     
         2 . The method of  claim 1 , wherein the first porosity is about 3% or more and the second porosity is less than about ⅘ths of the first porosity. 
     
     
         3 . The method of  claim 1 , wherein the sequential repetitions of (a) and (b) forms a plurality of polishing elements, each of the polishing elements comprising:
 an individual surface that forms a portion of a polishing surface of the polishing pad; and   one or more sidewalls extending downwardly from the individual surface to define a plurality of channels disposed between the polishing elements.   
     
     
         4 . The method of  claim 3 , wherein the plurality of polishing elements are disposed on a foundation layer, the one or more sidewalls of the individual polishing elements extend upwardly therefrom, and the method further comprises forming the foundation layer by sequential repetitions of:
 (d) dispensing a plurality of droplets of a second pre-polymer composition that is different from the first pre-polymer composition;   (e) at least partially curing the droplets of the second pre-polymer composition to form a portion of the foundation layer; and   (f) sequentially repeating (d) and (e).   
     
     
         5 . The method of  claim 3 , wherein at least one of the first regions is disposed proximate to a sidewall of the polishing element and the second region is disposed adjacent to the at least one first region. 
     
     
         6 . The method of  claim 5 , wherein the at least one first region disposed proximate to the sidewall has a width in a range of about 50 μm to about 2 mm. 
     
     
         7 . The method of  claim 3 , wherein the second region is disposed proximate to a sidewall of the polishing element and the at least one first region is disposed adjacent to the second region. 
     
     
         8 . The method of  claim 7 , wherein the second region disposed proximate to the sidewall has a width in a range of about 50 μm to about 5 mm. 
     
     
         9 . The method of  claim 1 , wherein the sacrificial material composition comprises a water soluble polymer. 
     
     
         10 . The method of  claim 9 , wherein the water soluble polymer is selected from 1-vinyl-2-pyrrolidone, vinylimidazole, polyethylene glycol diacrylate, acrylic acid, sodium styrenesulfonate, hydroxyethyl acrylate and [2-(methacryloyloxy)ethyltrimethylammonium chloride, 3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium, sodium 4-vinylbenzenesulfonate, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 2-acrylamido-2-methyl-1-propanesulfonic acid, vinylphosphonic acid, allyltriphenylphosphonium chloride, (vinylbenzyl)trimethylammonium chloride, allyltriphenylphosphonium chloride, (vinylbenzyl)trimethylammonium chloride, methoxy polyethylene glycol monoacrylate, methoxy polyethylene glycol diacrylate, methoxy polyethylene glycol triacrylate, or combinations thereof. 
     
     
         11 . The method of  claim 9 , wherein the first pre-polymer composition comprises:
 one or more functional oligomers;   one or more functional monomers;   one or more reactive diluents; and   one or more photoinitiators.   
     
     
         12 . A non-transitory computer-readable medium storing instructions that, when executed by a processor cause a computer system to perform:
 (a) dispensing droplets of a first pre-polymer composition and droplets of a sacrificial material composition onto a surface of a previously formed print layer according to a predetermined droplet dispense pattern; and   (b) at least partially curing the dispensed droplets of the first pre-polymer composition to form a print layer comprising at least portions of a polymer pad material having one or more first regions comprising a first porosity and one or more second regions comprising a second porosity disposed adjacent to the one or more first regions, wherein porosity is a volume of void-space or sacrificial material as a percentage of total volume in the respective first and second regions and the second porosity is less than the first porosity; and   (c) sequentially repeating (a) and (b).   
     
     
         13 . The non-transitory computer-readable medium of  claim 12 , wherein the sequential repetitions of (a) and (b) forms a plurality of polishing elements, each of the polishing elements comprising:
 an individual surface that forms a portion of a polishing surface of the polishing pad; and   one or more sidewalls extending downwardly from the individual surface to define a plurality of channels disposed between the polishing elements.   
     
     
         14 . The non-transitory computer-readable medium of  claim 13 , wherein the plurality of polishing elements are disposed on a foundation layer, the one or more sidewalls of the individual polishing elements extend upwardly therefrom, and further comprising forming the foundation layer by sequential repetitions of:
 (d) dispensing a plurality of droplets of a second pre-polymer composition that is different from the first pre-polymer composition;   (e) at least partially curing the droplets of the second pre-polymer composition to form a portion of the foundation layer; and   (f) sequentially repeating (d) and (e).   
     
     
         15 . A polishing pad, comprising:
 a plurality of polishing elements, each comprising:
 an individual surface that forms a portion of a polishing surface of the polishing pad; and 
 one or more sidewalls extending downwardly from the individual surface to define a plurality of channels disposed between the polishing elements, wherein
 each of the polishing elements is formed of a continuous phase of polymer material having one or more first regions comprising a first porosity and a second region comprising a second porosity, 
 porosity is a volume of void-space or sacrificial material as a percentage of total volume in the respective first and second regions, 
 the second porosity is less than the first porosity, 
 the one or more first regions comprising the first porosity having selectively arranged pores; and 
 the one or more first regions comprising the second porosity are disposed proximate to the one or more sidewalls and the second region comprising the first porosity is disposed inwardly from the one or more first regions. 
 
   
     
     
         16 . The polishing pad of  claim 15 , wherein the first porosity is about 3% or more and the second porosity is less than ⅘ths of the first porosity. 
     
     
         17 . The polishing pad of  claim 16 , wherein the second region comprises substantially no porosity. 
     
     
         18 . The polishing pad of  claim 17 , further comprising:
 a foundation layer, wherein   the plurality of polishing elements are disposed on the foundation layer,   the sidewalls of the individual polishing elements extend upwardly from a surface of the foundation layer, and   the foundation layer is formed of a different pre-polymer composition than a pre-polymer composition used to form the continuous phase of polymer material of the polishing elements.   
     
     
         19 . The polishing pad of  claim 15 , wherein the one or more first regions disposed proximate to the sidewall has a width in a range of about 50 μm to about 2 mm. 
     
     
         20 . The polishing pad of  claim 19 , wherein the second region disposed inwardly from the one or more first regions has a width in a range of about 50 μm to about 5 mm.