Polishing pad and method for manufacturing polishing pads

Abstract

A polishing pad comprising particles having an average diameter between 1 nanometer and 100 nanometers, wherein the total weight of the particles is greater than about 3% of the total weight of the pad. Also, a method of manufacturing a polishing pad comprises the steps of: mixing a pre-polymer and abrasive particles together; wherein the abrasive particles have an average diameter of between 1 nanometer and 100 nanometers in diameter, and wherein the abrasive particles comprise more than about 3% by weight of the polishing pad; mixing a curative with the mixed pre-polymer and particles; and pouring the mixture of pre-polymer, particles and curative into a mold. In one exemplary embodiment the particles are silica and the pre-polymer is a polyurethane pre-polymer.

1 . A method of tuning the material removal rate of a polishing pad on a workpiece, said polishing pad having embedded therein coated abrasive particles characterized by average diameters in the range of 1 to 100 nanometers, the method comprising the steps of: 
 a) providing a first polishing pad comprising a first quantity of coated particles having an average polarity of −X;    b) measuring the material removal rate of said first pad on a workpiece under CMP conditions;    c) providing an adjusted pad comprising a second quantity of coated particles having an average polarity of −Y;    d) measuring the material removal rate of said adjusted pad on a workpiece under CMP conditions; and    e) repeating steps c) and d) until a desired material removal rate is achieved.    
     
     
         2 . The method of  claim 1 , wherein said abrasive particles comprise silica particles.  
     
     
         3 . The method of  claim 1 , wherein said polarity is reduced to near zero.  
     
     
         4 . The method of  claim 1 , wherein said tuning comprises coating the particles, and wherein said coating is configured to modify the polarity of the particle and to facilitate mixing of said particles in concentrations greater than 25% by weight in the polishing pad.  
     
     
         5 . A method of tuning the material removal rate of a polishing pad, the method comprising the steps of: 
 selecting at least one type of an abrasive particle for incorporation of a plurality of said abrasive particles in said polishing pad;    selecting the size of said abrasive particles, wherein said plurality of abrasive particles have an average diameter of 1 to 100 nanometers;    selecting other materials used to form the pad, wherein one of said other materials is a pre-polymer;    tuning the polarity of at least a portion of a plurality of said abrasive particles, wherein said tuning is configured to obtain an optimal material removal rate (increase material removal rate); and    mixing said plurality of said abrasive particles with said other materials as part of the process of forming a polishing pad.    
     
     
         6 . The method of  claim 5 , wherein tuning the polarity of said abrasive particles comprises coating the particles, and wherein the coating renders the residual polarity near zero.  
     
     
         7 . The method of  claim 5 , wherein said coating is configured to modify the polarity of the particle and to facilitate mixing of said particles in concentrations greater than 25% by weight in the pad.  
     
     
         8 . The method of  claim 5 , wherein said abrasive particle type is a silica particle.  
     
     
         9 . The method of  claim 5 , wherein said tuning further comprises the steps of: 
 determining the pH of at least one of said other materials;    determining the initial polarity of said abrasive particle when uncoated;    determining the pH of final environment;    determining the desired polarity of final coated particle; and,    coating the particle to achieve a desired removal rate.    
     
     
         10 . A method of tuning the material removal rate of a polishing pad, the method comprising the steps of: 
 providing particles with a polarity X, wherein the initial size of said particles is in the range of 1-100 nanometers;    coating said particles to make the polarity Y, wherein the absolute value of X is greater than the absolute value of Y, wherein said coating is configured to modify the polarity of the particle and to facilitate mixing of said particles in concentrations greater than 25% by weight in the pad.    
     
     
         11 . The method of  claim 10 , wherein said initial particle size is in the range of 30 to 50 nanometers.  
     
     
         12 . The method of  claim 5 , wherein the coating renders the residual polarity near zero.  
     
     
         13 . The method of  claim 5 , wherein all of said particles are modified.  
     
     
         14 . The method of  claim 5 , wherein said polishing pad has an higher removal rate compared to a polishing pad that does not comprise coated particles.  
     
     
         15 . A polishing pad comprising: 
 a pre-polymer,    a plurality of particles mixed with said pre-polymer, wherein the plurality of particles have an average diameter of between 1 and 100 nanometers, and wherein the plurality of particles comprise greater than 3%, by weight, of the pad.    
     
     
         16 . The polishing pad of  claim 15 , wherein the pre-polymer is a polyurethane pre-polymer and wherein the plurality of particles are silica particles.  
     
     
         17 . The polishing pad of  claim 15 , wherein the pre-polymer is a polyurethane pre-polymer and wherein the plurality of particles are approximately 50 nm surface-modified silica particles.  
     
     
         18 . The polishing pad of  claim 15 , wherein the pre-polymer is a polyurethane pre-polymer and wherein the plurality of particles are configured to cause at least one of: a reduction in agglomeration, a reduction in binding due to colloidal forces, and a reduction in resistance to mixing of the pre-polymer and the poly urethane pre-polymer.  
     
     
         19 . The polishing pad of  claim 15 , wherein said coating is configured to modify the polarity of the particle and to facilitate mixing of said particles in concentrations greater than 25% by weight in the pad.  
     
     
         20 . A polishing pad comprising silica particles that have an average diameter of between 1 and 100 nanometers, wherein the silica particles are configured to facilitate a concentration of said silica particles in said pad, wherein said concentration of silica particles is greater than 3%, by weight, of the pad.  
     
     
         21 . The polishing pad of  claim 15 , wherein said concentration of silica particles is greater than 25%, by weight, of the pad.  
     
     
         22 . A method of manufacturing a polishing pad comprising the steps of: 
 mixing a pre-polymer and silica particles together; wherein the silica particles have an average diameter of between 1 and 100 nanometers, and comprises more than 3%, by weight, of the pre-polymer/silica particles mixture;    mixing a curative with the mixed pre-polymer and silica; and    pouring the mixture of pre-polymer, silica and curative into a mold.    
     
     
         23 . A polishing pad comprising a plurality of abrasive particles, wherein each of said plurality of abrasive particles has a particle diameter, wherein the average particle diameter of said plurality of abrasive particles is between 1 and 100 nanometers, and wherein the combined weight of said plurality of abrasive particles in said polishing pad is greater than 10% of the weight of said pad.  
     
     
         24 . The polishing pad of  claim 23 , wherein said plurality of abrasive particles comprise at least silica particles and wherein the polishing pad is configured to perform chemical mechanical polishing.  
     
     
         25 . The polishing pad of  claim 23 , wherein said plurality of abrasive particles are silica particles coated with a coating, and wherein said coating is configured to modify the polarity of the particle sufficiently to facilitate mixing of said particles in concentrations greater than 25% by weight in the pad.  
     
     
         26 . The polishing pad of  claim 23 , wherein said plurality of abrasive particles are silica particles coated with a coating and wherein said plurality of abrasive particles are formed of a particulate powder adapted for dispersion in organophilic polymers, the particulate powder being prepared from a sol precursor for the powder, 
 the outer surface of the powder particles having a first coating containing a reagent providing a surface reactive to an organic acid or an organic acid derivative; and    a second coating covering the first coating, the second coating containing an amphiphilic surfactant and the organic acid or organic acid derivative reactable with the reagent in the first coating,    the coated powder being characterized as being fully dispersible in the organophilic polymers substantially free from any agglomeration of the powder particles and without any change of the particle size distribution of the sol precursor of the powder before drying of the precursor to prepare the particulate powder.    
     
     
         27 . A particulate powder as defined in  claim 27  wherein the ultimate particles possess a mean particle size of between 1 and 100 nanometers, wherein the powder is silica, and wherein the reagent in the first coating comprises a reagent reversing the charge on the powder particles from an initial negative charge to a positive charge.  
     
     
         28 . An organophilic polymer having dispersed therein a powder as defined in  claim 27 , wherein the reagent in the first coating makes the surface of the first coating reactable with an organic acid or an organic acid derivative; and the second coating comprises an organic acid or organic acid derivative and an amphiphilic surfactant, and wherein the reagent in the first coating comprises a reagent reversing the charge on the powder particles from an initial negative charge to a positive charge.  
     
     
         29 . The polishing pad of  claim 27 , wherein said coating is configured to modify the polarity of the particle and to facilitate mixing of said particles in concentrations greater than 25% by weight in the pad.  
     
     
         30 . A polishing pad comprising silica particles, wherein the silica particles are greater than 3% by weight of the total weight of the pad, and wherein the polishing pad is more hydrophilic than a similar pad without the silica particles.