Polishing fluid and polishing method

Abstract

The present invention relates to polishing slurry and polishing method used for polishing in a process for forming wirings of a semiconductor device, and the like. There are provided polishing slurry giving a polished surface having high flatness even if the polished surface is made of two or more substances, and further, capable of suppressing metal residue and scratches after polishing, and a method of chemical mechanical polishing using this. The polishing slurry of the present invention is polishing slurry containing at least one of a surfactant and an organic solvent, and a metal oxide dissolving agent and water, or polishing slurry containing water and abrasive of which surface has been modified with an alkyl group, and preferably, it further contains a metal oxidizer, water-soluble polymer, and metal inhibitor.

1 . Polishing slurry comprising a surfactant, metal oxide dissolving agent and water, and used for polishing of at least a barrier conductor layer and a conductive substance.  
     
     
         2 . Polishing slurry comprising an organic solvent, metal oxide dissolving agent and water, and used for polishing of at least a barrier conductor layer and a conductive substance.  
     
     
         3 . The polishing slurry according to  claim 1  or  2 , comprising abrasive.  
     
     
         4 . The polishing slurry according to  claim 3 , wherein the abrasive is at least one selected from silica, alumina, ceria, titania, zirconia and germania.  
     
     
         5 . The polishing slurry according to  claim 3 , wherein the surface of the abrasive is modified with an alkyl group.  
     
     
         6 . Polishing slurry comprising abrasive and water and used for polishing of at least a barrier conductor layer and a conductive substance wherein the surface of the abrasive is modified with an alkyl group.  
     
     
         7 . The polishing slurry according to  claim 6 , wherein the abrasive is at least one selected from silica, alumina, ceria, titania, zirconia and germania of which surface is modified with an alkyl group.  
     
     
         8 . The polishing slurry according to  claim 6  or  7 , comprising a metal oxide dissolving agent.  
     
     
         9 . The polishing slurry according to  claim 6  or  7 , comprising at least one of a surfactant and an organic solvent.  
     
     
         10 . The polishing slurry according to  claim 1  or  2 , wherein the metal oxide dissolving agent is at least one selected from organic acids, esters of organic acids, ammonium salts of organic acids and sulfuric acid.  
     
     
         11 . The polishing slurry according to  claim 2 , wherein the organic solvent is contained in a proportion of 0.1 to 95 wt %.  
     
     
         12 . The polishing slurry according to  claim 2 , wherein the organic solvent is at least one selected from glycols and derivatives thereof, alcohols and carbonic esters.  
     
     
         13 . The polishing slurry according to  claim 1 , wherein the surfactant is at least one selected from nonionic surfactants and anionic surfactants.  
     
     
         14 . The polishing slurry according to  claim 1 , wherein the surfactant is at least one selected from perfluoroalkanesulfonic acids and derivatives thereof.  
     
     
         15 . The polishing slurry according to  claim 1 , wherein the surfactant is contained in a proportion of 0.00001 to 20 wt %.  
     
     
         16 . The polishing slurry according to  claim 1  or  2 , comprising a metal oxidizer.  
     
     
         17 . The polishing slurry according to  claim 16 , wherein the metal oxidizer is at least one selected from hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid and ozone water.  
     
     
         18 . The polishing slurry according to  claim 1  or  2 , comprising a water-soluble polymer having a weight-average molecular weight of 500 or more.  
     
     
         19 . The polishing slurry according to  claim 18 , wherein the water-soluble polymer is at least one selected from polysaccharides, polycarboxylic acids, polycarboxylic esters and salts thereof, and vinyl-based polymers.  
     
     
         20 . A polishing method comprising a first polishing process of polishing a conductive substance layer of a substrate having an interlayer insulating film carrying a surface composed of a concave portion and a convex portion, a barrier conductor layer coating the interlayer insulating film along its surface and a conductive substance layer filling the concave portion to coat the barrier conductor layer, to expose the barrier conductor layer on the convex portion, and a second polishing process of chemical mechanical polishing at least the barrier conductor layer and the conductive substance layer on the concave portion while feeding the polishing slurry according to  claim 1  or  2  to expose the interlayer insulating film on the convex portion.  
     
     
         21 . The polishing method according to  claim 20 , wherein the interlayer insulating film is a silicon-based film or an organic polymer film.  
     
     
         22 . The polishing method according to  claim 20 , wherein the conductive substance is mainly composed of copper.  
     
     
         23 . The polishing method according to  claim 20 , wherein the barrier conductor layer is a barrier layer of preventing diffusion of the conductive substance into the interlayer insulating film, and comprises at least one selected from tantalum, tantalum nitride, tantalum alloy, other tantalum compounds, titanium, titanium nitride, titanium alloy, other titanium compounds, tungsten, tungsten nitride, tungsten alloy, and other tungsten compounds.  
     
     
         24 . The polishing slurry according to any of claims  1 ,  2  and  6 , used for polishing of parts of the interlayer insulating film, in addition to polishing of the barrier conductor layer and the conductive substance.  
     
     
         25 . The polishing slurry according to  claim 24 , wherein the interlayer insulating film is a silicon-based film or an organic polymer film.  
     
     
         26 . The polishing slurry according to any of claims  1 ,  2  and  6 , wherein the conductive substance is mainly composed of copper.  
     
     
         27 . The polishing slurry according to any of claims  1 ,  2  and  6 , wherein the barrier conductor layer is a barrier layer of preventing diffusion of the conductive substance into the interlayer insulating film, and comprises at least one selected from tantalum, tantalum nitride, tantalum alloy, other tantalum compounds, titanium, titanium nitride, titanium alloy, other titanium compounds, tungsten, tungsten nitride, tungsten alloy, and other tungsten compounds.  
     
     
         28 . The polishing method according to  claim 20 , for polishing of parts of the interlayer insulating film, in addition to polishing of the barrier conductor layer and the conductive substance.