发明授权
- 专利标题: Reduced area butting contact structure
- 专利标题(中): 减少对接接触结构
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申请号: US230696申请日: 1988-08-05
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公开(公告)号: US4912540A公开(公告)日: 1990-03-27
- 发明人: Craig S. Sander , Richard K. Klein , Tat C. Choi
- 申请人: Craig S. Sander , Richard K. Klein , Tat C. Choi
- 申请人地址: CA Sunnyvale
- 专利权人: Advanced Micro Devices, Inc.
- 当前专利权人: Advanced Micro Devices, Inc.
- 当前专利权人地址: CA Sunnyvale
- 主分类号: H01L21/768
- IPC分类号: H01L21/768 ; H01L29/04 ; H01L23/48 ; H01L29/34
摘要:
A reduced area butting contact structure (10') is provided, which is especially suited for four-transistor static RAM cells. A structure is formed which includes a doped silicon region and one or more layers of polysilicon and oxide situated thereabove, one of which layers of polysilicon may be a gate polysilicon. An anisotropic etch is then performed through all upper layers including any upper polysilicon layers which may be present, but stopping at the doped silicon region and any gate polysilicon layers present, to form a contact hole (26'). The contact hole is filled with a conductive plug (32) of a material such as tungsten or polysilicon and etched back. In either case, contact with all polysilicon layers present and the doped silicon region is made. In the anisotropic etching process, a two-step etch is employed. The first etch is non-specific as to material, etching all relevant materials (polysilicon and oxide) at substantially the same rate and is continued through any upper polysilicon layers, but is terminated prior to etching the doped silicon region or any gate polysilicon layers (22). The second etch is specific as to material, etching silicon dioxide faster than polysilicon or silicon, and thus stops at the gate polysilicon layer and the doped silicon region.
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