Ex parte SUNAMI et al. - Page 5

               Appeal No. 1997-1808                                                                             Page 5                 
               Application No. 08/172,101                                                                                              

                       Upon a reading of the Specification as a whole, what naturally occurs to the reader is that the                 

               inventors have further improved upon a very specific prior art semiconductor device containing a                        

               capacitor plate composed of polysilicon (poly-Si) doped with phosphorus or arsenic.  The invention is                   

               described as an improvement over the prior art devices of Figures 4 and 5.  Those prior art devices are                 

               fabricated by forming a plate 8 “typically formed of poly-Si doped with phosphorus P or arsenic As”                     

               and oxidizing the surface of the plate 8 “to form a first interlayer oxide film 13.” (Specification, page 6).           

               The plate electrode 8 within the groove, as shown in Figure 6, is also described on page 9 as being                     

               formed of poly-Si.  Then the Specification, in disclosing the invention, specifically sets forth a process of           

               depositing poly-Si into a groove, doping with phosphorus or arsenic to form the capacitor plate 8, and                  

               then oxidizing the doped poly-Si to form silicon dioxide on the surface.  The groove is then filled with                

               more poly-Si and etched to embed the poly-Si in the groove and remove excess poly-Si to provide a                       

               planar surface for the deposition of further layers (Specification, page 19, line 22 to page 20, line 14;               

               Fig. 19).                                                                                                               

                       At no point does the Specification indicate using materials other than poly-Si for the plate 8 and              

               filling layer 82.  The etch stop layer is specifically disclosed as formed by thermal oxidation of the poly-            

               Si of the capacitor plate to form a layer of silicon dioxide.  No other materials or processes are                      

               disclosed for forming the etch stop.                                                                                    

                       We agree with Appellants that the advantage of using a silicon dioxide film on the poly-Si film 8               

               in order to protect the film 8 during etching of the second poly-Si film is clearly disclosed in the                    

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