Polishing pad for use in chemical - mechanical palanarization of semiconductor wafers and method of making same

Abstract

A polishing pad for use in chemical mechanical polishing of substrates that being made of fibrous matrix such as cellulose with a binder consisting of thermoset resin material, such as phenolic resin. The polishing surface is ground to form asperities. The polishing pad provides a porous structure by which polishing slurry and polishing debris during chemical mechanical polishing of substrates are stored for subsequent rinsing away, and for enhanced flow-distribution of the polishing slurry. Also disclosed is a method of making the polishing pad.

1 - 17 . (canceled)  
     
     
         18 . A method of making a fiber matrix as a medium for subsequent resin impregnation, for use in pads for chemical-mechanical polishing of substrates, comprising: 
 making said fiber matrix made by a paper-making wet-laid process comprising the following steps:    (a) dispersing paper-making cellulosic fibers in water to form a paper-making slurry;    (b) delivering the paper-making slurry of said step (a) to a paper-making machine and making a paper sheet in said paper-making machine;    (c) said step (b) comprising draining water from the slurry to form a continuous paper sheet;    (d) drying the wet-laid continuous paper sheet of said step (c) for creating a relatively soft, compliant fiber matrix from which polishing pads for use in chemical mechanical polishing of substrates are formed;    (e) cutting said dried sheet of said step (d) into a series of CMP polishing pads.    
     
     
         19 . The method according to  claim 18 , wherein said steps (b) through (d) are performed by at least one of the following: a handsheet mold, a fourdrinier machine, an incline wire machinery, roto-former machine, twin wire machine.  
     
     
         20 . The method according to  claim 18 , wherein said steps (b) through (d) are performed by using a suction process.  
     
     
         21 . The method according to  claim 18 , wherein said step (a) also comprises dispersing a latex binder, or equivalent thereof, in the water to form a slurry of fibers and binder.  
     
     
         22 . The method according to  claim 19 , further comprising, before said step (d), applying a latex binder, or equivalent thereof, to the fiber surfaces.  
     
     
         23 . A method of forming polishing pads for use in chemical mechanical polishing of substrates, comprising: 
 (a) forming a fiber matrix sheet made of paper-making fibers on a paper-making machine;    (b) impregnating the fiber matrix sheet with a binder material;    (c) curing the binder material with heat to form a fiber matrix sheet that is relatively soft and compliant;    (d) said step (b) comprising binding the fiber matrix with a thermoset resin.    
     
     
         24 . The method according to  claim 23 , wherein said step (d) comprises using a binder from at least one of the following: phenolic, epoxy, silicone, and modified phenolics, wherein said step) (b) is done by soaking the fiber matrix sheet in a bath of liquid resin.  
     
     
         25 . The method according to  claim 23 , wherein said step (d) comprises exposing the fiber matrix to curtains of liquid resin, or spraying liquid resin onto the fiber matrix.  
     
     
         26 . The method according to  claim 23 , further comprising densifying the resin impregnated matrix.  
     
     
         27 . The method according to  claim 23 , further comprising forming a grooved-surface pattern in the surface of the fiber matrix sheet.  
     
     
         28 . The method according to  claim 27 , wherein said step of forming a grooved-surface pattern is performed after the thermoset resin is fully cured.  
     
     
         29 . The method according to  claim 28 , wherein said step of forming a grooved-surface pattern comprises embossing the grooved-surface pattern.  
     
     
         30 - 40 . (canceled)  
     
     
         41 . The method according to  claim 18 , wherein said step (a) further comprises adding thermoset resin material in addition to said paper-making cellulosic fibers and water to form said a paper-making slurry; 
 said method further comprising:    (e) curing said continuous paper sheet after said step (d).    
     
     
         42 . The method according to  claim 18 , wherein said step (a) further comprises adding thermoset resin material in addition to said paper-making cellulosic fibers and water to form said a paper-making slurry; said step (e) comprising cutting said continuous paper sheet after said step (d) into pad-sized blanks, and then curing said pad-sized blanks.  
     
     
         43 . The method according to  claim 18 , wherein said method further comprises: 
 (f) impregnating said continuous paper sheet with thermoset resin; and    (g) curing said continuous paper sheet after said step (f).