Method of chemical mechanical polishing, and a pad provided therefore

Abstract

In a chemical mechanical polishing for removing a barrier and subsequent buffing a polyurethane polishing pad is used which is composed of for removal a barrier and buffing after a bulk copper removal to the barrier in a chemical mechanical polishing of a copper film deposited on a surface of a semiconductor wafer, at least one layer of the polishing pad is made from a mix composed of the prepolymer with an isocyanate concentration of between substantially 6.5% and 11.0% or from a monomer and an addition of isocyanate required to achieve a same molal concentration, with a shore D hardness less than substantially 35%.

1 . A method of chemical mechanical polishing of a copper film deposited on a surface of a semiconductor wafer, comprising the steps of removing a bulk copper to a barrier; removing the barrier; and subsequently buffing, wherein said barrier removal and buffing including using a polyurethane polishing pad at least one layer of which is made of a mix composed of a prepolymer or a monomer and an addition of an isocyanate at a concentration of between substantially 6.5% and 11.0% or from a monomer and an addition of isocyanate required to achieve a same molal concentration, in which a shore D hardness is less than substantially 35%.  
     
     
         2 . A method as defined in  claim 1 , wherein the pad has an additive including a methyl alcohol.  
     
     
         3 . A method as defined in  claim 1 , wherein the pad has an additive which includes water.  
     
     
         4 . A method as defined in  claim 1 , wherein the pad has an additive which includes starch.  
     
     
         5 . A method as defined in  claim 1 , wherein the pad has a thickness between 10 mils and 200 mils.  
     
     
         6 . A method as defined in  claim 5 , wherein the pad has a thickness of between 40 and 100 mils.  
     
     
         7 . A method as defined in  claim 1 , wherein the pad is a single open-layered pad.  
     
     
         8 . A method as defined in  claim 1 , wherein the pad is stacked on and attached to a sub pad.  
     
     
         9 . A method as defined in  claim 1 , wherein said is a pad selected from the group consisting of a groove pad and an ungrooved pad.  
     
     
         10 . A method as defined in  claim 1 , wherein said pad is a pad selected from the group consisting of a perforated pad and an unperforated pad.  
     
     
         11 . A method as defined in  claim 1 , wherein said layer is composed of said polyurethane selected from the group consisting of a polyether polyurethane and polyester polyurethane.  
     
     
         12 . A method as defined in  claim 1;  and further comprising introducing in said layer abrasive particles selected from the group consisting of silica, alumina, ceria, titania, diamond and silicon carbide.  
     
     
         13 . A method as defined in  claim 1;  and further comprising introducing a filler into said mix.  
     
     
         14 . A polishing pad for removal of a barrier and buffing after a bulk copper removal to the barrier in a chemical mechanical polishing of a copper film deposited on a surface of a semiconductor wafer, the polishing pad having at least one layer made of a mix is composed of a prepolymer with an isocyanate concentration of between substantially 6.5% and 11.0% or from a monomer and an addition of isocyanate required to achieve a same molal concentration, with a shore D hardness less than substantially 35%.  
     
     
         15 . A polishing pad as defined in  claim 14 , wherein the pad has an additive including a methyl alcohol.  
     
     
         16 . A polishing pad as defined in  claim 14 , wherein the pad has an additive which includes water.  
     
     
         17 . A polishing pad as defined in  claim 14 , wherein the pad has an additive which includes starch.  
     
     
         18 . A polishing pad as defined in  claim 14 , wherein the pad has a thickness between 10 mils and 200 mils.  
     
     
         19 . A polishing pad as defined in  claim 14 , wherein the pad has a thickness of between 40 and 100 mils.  
     
     
         20 . A polishing pad as defined in  claim 17 , wherein the pad is a single open-layered pad.  
     
     
         21 . A polishing pad as defined in  claim 14 , wherein the pad is stacked on and attached to a sub pad.  
     
     
         22 . A polishing pad as defined in  claim 14 , wherein said is a pad selected from the group consisting of a groove pad and an ungrooved pad.  
     
     
         23 . A polishing pad defined in  claim 14 , wherein said pad is a pad selected from the group consisting of a perforated pad and an unperforated pad.  
     
     
         24 . A polishing pad as defined in  claim 14 , wherein said layer is composed of said polyurethane selected from the group consisting of a polyether polyurethane and polyester polyurethane.  
     
     
         25 . A polishing pad as defined in  claim 14;  and further comprising in said layer, abrasive particles selected from the group consisting of fssilica, alumina, ceria, titania, diamond and silicon carbide.  
     
     
         26 . A polishing pad as defined in  claim 14;  and further comprising a filler introduced into said mix.  
     
     
         27 . A method of chemical mechanical polishing of a copper film deposited on a surface of a semiconductor wafer, comprising the steps of removing bulk copper to a barrier; removing the barrier; and subsequently buffing, wherein said barrier removal and buffing include using a polyurethane polishing pad at least one layer of which is made from a mix composed of a prepolymer with an isocyanate concentration of between substantially 6.5% and 8.5% or from a monomer and an addition of isocyanate required to achieve a same molal concentration, in which a shore D hardness is less than substantially 35%.