Polyurethane urea polishing pad

Abstract

The present invention relates to an article for altering a surface of a workpiece, or a polishing pad having a window. In particular, the polishing pad includes a polyurethane urea material wherein the polyurethane urea material contains cells which are at least partially filled with gas. The polyurethane urea material can be prepared by combining polyisocyanate and/or polyurethane prepolymer, hydroxyl-containing material, amine-containing material and blowing agent. The polishing pad according to the present invention is useful for polishing articles, and is especially useful for chemical mechanical polishing or planarization of microelectronic and optical electronic devices such as but not limited to semiconductor wafers. The window of the polishing pad is at least partially transparent and thus, can be particularly useful with polishing or planarizing tools that are equipped with through-the-platen wafer metrology.

1 . A polyurethane urea-containing pad adapted to polish a microelectronic substrate, said pad comprising an at least partially transparent window formed by a cast-in-place process, wherein said polyurethane urea comprises at least partially gas-filled cells, and wherein at least a portion of said at least partially gas-filled cells is formed by an in-situ reaction.  
     
     
         2 . The pad of  claim 1  wherein said pad comprises the reaction product of polyisocyanate, hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         3 . The pad of  claim 1  wherein said pad comprises the reaction product of polyurethane prepolymer amine-containing material and blowing agent.  
     
     
         4 . The pad of  claim 1  wherein said pad comprises the reaction product of polyisocyanate and polyurethane prepolymer, optional hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         5 . The pad of  claim 1  further comprising a sub-pad.  
     
     
         6 . The pad of  claim 5  wherein said sub-pad can be chosen from non-woven fiber mat, woven fiber mat, or combinations thereof.  
     
     
         7 . The pad of  claim 6  wherein said sub-pad is chosen from polyolefin, polyester, polyamide, or acrylic fibers which have been impregnated with a resin, and combinations thereof.  
     
     
         8 . The pad of  claim 5  wherein said sub-pad is chosen from foam sheet made of natural rubbers, synthetic rubbers, thermoplastic elastomers; polyurethane and polyurethane urea impregnated felt; and combinations thereof.  
     
     
         9 . The pad of  claim 5  wherein said pad is at least partially connected to said sub-pad.  
     
     
         10 . The pad of  claim 1  further comprising a second layer.  
     
     
         11 . The pad of  claim 10  wherein said second layer is at least partially connected to said pad.  
     
     
         12 . The pad of  claim 11  wherein said second layer is at least partially connected to a sub-pad.  
     
     
         13 . The pad of  claim 10  wherein said second layer is chosen from polyolefins, cellulose-based polymers, acrylics, polyesters and co-polyesters, polycarbonates, polyamides, plastics, and combinations thereof.  
     
     
         14 . The pad of  claim 10  wherein said second layer is chosen from substantially non-compressible polymers, metallic films and foils, and combinations thereof.  
     
     
         15 . The pad of  claim 1  wherein said window comprises a polymer derived from a resin material.  
     
     
         16 . The pad of  claim 15  wherein said resin material is chosen from polyurethane prepolymers with curative, epoxy resins with curative, ultraviolet curable acrylics, and mixtures thereof.  
     
     
         17 . The pad of  claim 15  wherein said resin material is chosen from thermoplastic acrylic resins, thermoset acrylic resins, urethane systems, epoxy resins, polyester resins, and mixtures thereof.  
     
     
         18 . The pad of  claim 15  wherein said resin material is chosen from hydroxyl-functional acrylic resins crosslinked with urea-formaldehyde or melamine-formaldehyde resins, hydroxyl-functional acrylic resins crosslinked with epoxy resins, or carboxyfunctional acrylic resins crosslinked with carbodiimides or polyimines or epoxy resins, hydroxyfunctional acrylic resins crosslinked with polyisocyanate, diamine cured isocyanate-terminated prepolymers, isocyanate-terminated prepolymers crosslinked with polyamines, amine-terminated resins crosslinked with polyisocyanates, carbamate-functional acrylic resins crosslinked with melamine-formaldehyde resins, polyamide resin crosslinked with bisphenol A epoxy resins, phenolic resins crosslinked with bisphenol A epoxy resins, hydroxyl-terminated polyesters crosslinked with melamine-formaldehyde resins or with polyisocyanates or with epoxy crosslinkers, and mixtures thereof.  
     
     
         19 . The pad of  claim 15  wherein said resin material comprises amine-terminated oligomer, diamine, and polyisocyanate.  
     
     
         20 . The pad of  claim 1  wherein said window is at least partially transparent to at least one wavelength in the range of from 190 to 3500 nanometers.  
     
     
         21 . The pad of  claim 1  wherein said cure temperature is from 5° C. to 120° C.  
     
     
         22 . The pad of  claim 1  wherein said cure temperature is from 10° C. to 115° C.  
     
     
         23 . The pad of  claim 1  wherein said cure temperature is from 15° C. to 110° C.  
     
     
         24 . The pad of  claim 1  wherein said cure temperature is from 22° C. to 105° C.  
     
     
         25 . A device for polishing a microelectronic substrate, said device comprising: 
 a pad having a pair of spaced surfaces, at least a portion of said pad comprising a closed-cell polyurethane urea foam having gas-containing cells formed by an in-situ reaction; and    a window in said pad, said window comprising an aperture in said pad extending through said surfaces, and a translucent panel attached to said pad within the aperture, said panel being formed in said aperture by a cast-in-place process.    
     
     
         26 . The device of  claim 25  wherein said pad further comprises a sub-pad.  
     
     
         27 . The device of  claim 25  wherein said pad comprises the reaction product of polyisocyanate, hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         28 . The device of  claim 25  wherein said pad comprises the reaction product of polyurethane prepolymer, amine-containing material and blowing agent.  
     
     
         29 . The device of  claim 25  wherein said pad comprises the reaction product of polyisocyanate and polyurethane prepolymer, optional hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         30 . The device of  claim 25  wherein said window comprises a resin material.  
     
     
         31 . The device of  claim 25  wherein said resin material is chosen from polyurethane prepolymers with curative, epoxy resins with curative, ultraviolet curable acrylics, and mixtures thereof.  
     
     
         32 . The device of  claim 25  wherein said window is at least partially transparent to at least one wavelength in the range of from 190 to 3500 nanometers.  
     
     
         33 . A method for producing a polishing pad comprising an at least partially transparent window, comprising: 
 a. forming a polyurethane urea-containing pad wherein said polyurethane urea comprises at least partially gas-filled cells, and wherein at least a portion of said at least partially gas-filled cells is formed in-situ;    b. producing an opening into said pad;    c. inserting a spacer into said opening;    d. filling said opening above said spacer with a resin material; and    e. allowing said resin material to cure at a temperature of from 0° C. to less than 125° C.    
     
     
         34 . The method of  claim 33  further comprising: 
 f. removing said spacer.    
     
     
         35 . The method of  claim 33  wherein said pad is the reaction product of polyisocyanate, hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         36 . The method of  claim 31  wherein said pad is the reaction product of polyurethane prepolymer, amine-containing material and blowing agent.  
     
     
         37 . The method of  claim 33  wherein said pad is the reaction product of polyisocyanate and polyurethane prepolymer, optional hydroxyl-containing material, amine-containing material and blowing agent.  
     
     
         38 . The method of  claim 33  further comprising at least partially connecting to said pad a sub-pad; producing an opening in said sub-pad; and at least partially aligning said opening of said pad and said opening of said sub-pad.  
     
     
         39 . The method of  claim 33  further comprising at least partially connecting said pad to a second layer and at least partially connecting said second layer to a sub-pad; producing an opening in said second layer and said sub-pad; and at least partially aligning said opening in said polishing pad, said opening in said second layer and said opening in said sub-pad.  
     
     
         40 . The method of  claim 33  wherein said resin material is chosen from polyurethane prepolymers with curative, epoxy resins with curative, ultraviolet curable acrylics, and mixtures thereof.  
     
     
         41 . The method of  claim 33  wherein said window is at least partially transparent to wavelengths in the range of from 190 to 3500 nanometers.  
     
     
         42 . The method of  claim 33  wherein in step d, an amount of resin is used to fill said spacer such that said resin is flush with a polishing surface of said pad.  
     
     
         43 . The method of  claim 31  wherein in step e said temperature for cure is from 5° C. to 120° C.  
     
     
         44 . The method of  claim 31  wherein in step e said temperature for cure is from 10° C. to 115° C.  
     
     
         45 . The method of  claim 31  wherein in step e said temperature for cure is from 15° C. to 110° C.  
     
     
         46 . The method of  claim 31  wherein in step e said temperature for cure is from 22° C. to 105° C.  
     
     
         47 . A polishing pad having an at least partially transparent window wherein formation of said window comprises forming a polishing pad and a second layer, at least partially connecting said polishing pad to said second layer; producing an opening into said polishing pad and said second layer such that said opening in said polishing pad is at least partially aligned with said opening in said second layer; inserting a spacer into said opening; filling opening above said spacer with a resin material; allowing said resin material to cure at a temperature of from 0° C. to less than 125° C., and removing said spacer.