Polishing pad comprising magnetically sensitive particles and method for the use thereof

Abstract

The invention provides polishing pads comprising a deformable polishing pad body and magnetically sensitive particles dispersed therein, wherein one or more properties of the polishing pad are altered when in the presence of an applied magnetic field. The invention further provides a polishing system and a method for polishing a substrate involving such a polishing pad.

1 - 30 . (canceled)  
     
     
         31 . A polishing system comprising 
 (a) a polishing pad comprising a deformable polishing pad body and magnetically sensitive particles dispersed therein, wherein one or more properties of the polishing pad are altered when in the presence of an applied magnetic field, and    (b) an adjustable-strength magnetic field positioned proximate to the polishing pad.    
     
     
         32 . The polishing system of  claim 31 , wherein the strength of the magnetic field is manually controlled.  
     
     
         33 . The polishing system of  claim 31 , wherein the strength of the magnetic field is automatically controlled.  
     
     
         34 . The polishing system of  claim 33 , wherein the strength of the magnetic field automatically adjusts in response to changes in polishing conditions.  
     
     
         35 . The polishing system of  claim 33 , wherein the strength of the magnetic field automatically adjusts according to a pre-set program.  
     
     
         36 . The polishing system of  claim 31 , wherein the one or more properties of the polishing pad that are altered in the presence of an applied magnetic field are one or more properties selected from the group consisting of the storage modulus, compressibility, percent-rebound, and hardness of the polishing pad.  
     
     
         37 . A method of polishing a substrate comprising 
 (a) providing a polishing pad comprising a deformable polishing pad body and magnetically sensitive particles dispersed therein, wherein one or more properties of the polishing pad are altered when in the presence of an applied magnetic field,    (b) contacting the polishing pad with a substrate,    (c) applying a magnetic field to the polishing pad to alter one or more properties of the polishing pad, and    (d) moving the polishing pad relative to the substrate, thereby polishing the substrate.    
     
     
         38 . The method of  claim 37 , further comprising adjusting the strength of the magnetic field during polishing, thereby altering one or more properties of the polishing pad.  
     
     
         39 . The method of  claim 37 , wherein the strength of the magnetic field is adjusted in response to a change in polishing conditions.  
     
     
         40 . The method of  claim 38 , wherein the strength of the magnetic field is adjusted according to a pre-set program.  
     
     
         41 . The method of  claim 38 , wherein adjusting the strength of the magnetic field reduces over-polishing dishing in the substrate.  
     
     
         42 . The method of  claim 37 , wherein the one or more properties of the polishing pad that are altered in the presence of an applied magnetic field axe one or more properties selected from the group consisting of the storage modulus, compressibility, resilience, and hardness of the polishing pad.  
     
     
         43 . The polishing system of  claim 31 , wherein the polishing pad has a storage modulus of about 100 to about 1000 MPa in the absence of an applied magnetic field.  
     
     
         44 . The polishing system of  claim 31 , wherein the polishing pad has an average percent compressibility, under a load of about 32 kPa, of about 2% or more in the absence of an applied magnetic field.  
     
     
         45 . The polishing system of  claim 31 , wherein the polishing pad has an average percent-rebound, after application of a load of about 32 kPa, of about 25% or more in the absence of an applied magnetic field.  
     
     
         46 . The polishing system of  claim 31 , wherein the polishing pad has a Shore Durometer hardness of about 40 A to about 90 D in the absence of an applied magnetic field.  
     
     
         47 . The polishing system of  claim 31 , wherein the deformable polishing pad body comprises a polymer.  
     
     
         48 . The polishing system of  claim 47 , wherein the polymer is selected from the group consisting of elastomers, polyurethanes, polyolefins, polycarbonates, polyvinylalcohols, nylons, natural and synthetic rubbers, styrenic polymers, polyaromatics, fluoropolymers, polyimides, cross-linked polyurethanes, thermoset polyurethanes, cross-linked polyolefins, polyethers, polyesters, polyacrylates, elastomeric polyethylenes, copolymers and block copolymers thereof, and mixtures and blends thereof.  
     
     
         49 . The polishing system of  claim 48 , wherein the deformable polishing pad body comprises a foam polymer.  
     
     
         50 . The polishing system of  claim 49 , wherein the foam comprises predominantly open cells.  
     
     
         51 . The polishing system of  claim 49 , wherein the foam comprises predominantly closed cells.  
     
     
         52 . The polishing system of  claim 49 , wherein the foam comprises a mixture of open and closed cells.  
     
     
         53 . The polishing system of  claim 31 , wherein the magnetically sensitive particles have an average particle diameter of about 5 μm or less.  
     
     
         54 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are inorganic particles.  
     
     
         55 . The polishing system of  claim 54 , wherein the magnetically sensitive particles are selected from the group consisting of Fe 3 O 4 , Nd—Fe—B, Ba—Sr ferrite, Ni—Zn—Cu ferrite, SmCo 5 , Sm 2 Co 17 , iron, steel, and mixtures thereof.  
     
     
         56 . The polishing system of  claim 54 , wherein the magnetically sensitive particles are coated.  
     
     
         57 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are organic or metal-organic particles.  
     
     
         58 . The polishing system of  claim 57 , wherein the magnetically sensitive particles are selected from the group consisting of V[tetracyanoethylene] ˜2 , V[Cr(CN)] ˜0.9 , Cr(tetracyanoethylene) 2 , KV[Cr(CN) 6 ], and C-60 fullerene.  
     
     
         59 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are distributed uniformly throughout the deformable polishing pad body.  
     
     
         60 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are distributed throughout the deformable polishing pad body in a non-uniform manner.  
     
     
         61 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are distributed throughout the deformable polishing pad body according to a gradient.  
     
     
         62 . The polishing system of  claim 31 , wherein the magnetically sensitive particles are distributed in selected areas of the pad.  
     
     
         63 . The polishing system of  claim 31  further comprising a polishing surface.  
     
     
         64 . The polishing system of  claim 63 , wherein the polishing surface is provided by a surface of the deformable polishing pad body.  
     
     
         65 . The polishing system of  claim 63 , wherein the polishing surface is provided by a separate layer.  
     
     
         66 . The polishing system of  claim 63 , wherein the polishing surface comprises magnetically sensitive particles.  
     
     
         67 . The polishing system of  claim 66 , wherein the magnetically sensitive particles are coated particles.  
     
     
         68 . The polishing system of  claim 66 , wherein the magnetically sensitive particles are organic particles or metal-organic.  
     
     
         69 . The polishing system of  claim 63 , wherein the polishing surface is free of magnetically sensitive particles.  
     
     
         70 . The polishing system of  claim 31 , further comprising an endpoint detection port.