Ex parte YAMAMICHI et al. - Page 3




          Appeal No. 1997-4024                                                        
          Application No. 08/299,407                                                  


          process, but such an etching process makes it difficult to                  
          remove the polysilicon layer evenly across its surface                      
          "because the area within the contact holes can easily become                
          overetched due to the microloading effect" (page 3 of                       
          principal brief).  According to appellants:                                 
               The present invention solves the problem of                            
               overetching and resulting convex and concave                           
               portions of the interlayer insulating film by                          
               employing not a dry etching process, but rather a                      
               chemical and mechanical polishing process using                        
               piperazine or colloidal silica slurry to flatten the                   
               polysilicon layer 3 or secondary interlayer                            
               insulating film 7 [page 4 of principal brief].                         
               Appealed claims 1-8 stand rejected under 35 U.S.C.  103               
          as being unpatentable over Yamamichi.                                       
               Upon careful consideration of the opposing arguments                   
          presented on appeal, we concur with appellants that the                     
          examiner has failed to establish a prima facie case of                      
          obviousness for the claimed subject matter.  Accordingly, we                
          will not sustain the examiner's rejection.                                  
               The examiner concedes that Yamamichi "fails to teach                   
          flattening the surface of the polysilicon layer by chemical or              
          mechanical polishing by piperazine or colloidal silica slurry"              
          (page 4 of Answer).  Hence, the single reference applied by                 
          the examiner fails to teach or suggest the essence of                       
                                         -3-                                          




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