Planarization method and system using variable exposure
AssigneeKabushiki Kaisha Toshiba
InventorsTakashi Sato, Katsuya Okumura, Junichiro Iba
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Abstract
A method and system for planarization is disclosed. The system includes a mask including a medium density, sub-resolution region which allows less than the full intensity of the exposing radiation through to a resist layer. By including multiple density regions, improved planarization can be achieved.
Claims14
A process for planarizing a contoured topographic surface of a semiconductor wafer comprising the steps of:
- applying a resist to said contoured topographic surface, said resist having a topographical contour substantially matching the contour of said contoured topographic surface;
- exposing selected portions of said resist on said contoured topographic surface to radiation through a variable density pattern mask, said variable density pattern mask having a plurality of densities relating to said topographical contour of said resist;
- and
- developing said resist and leaving a developed resist layer with a substantially planar surface.
A process for planarizing a surface of a semiconductor wafer which includes at least one feature and a uniform thickness resist layer coating said surface, said resist layer coating having a contoured topography in response to coating said at least one feature on said wafer, said process including the step of:
- exposing said resist through a mask having patterns relating to said contoured topography and said at least one feature, so that when developed the resist layer varies in thickness so as to compensate for a topography of said at least one feature, leaving a developed resist layer with a substantially planar surface.
A process for planarizing a surface of a semiconductor wafer which includes a first region with multiple deep trenches and a second region apart from said first region, said wafer including a coated resist layer whose thickness is greater over said second region than over said first region, said process including the step of:
- exposing said first region with radiation of a first intensity and exposing said second region with radiation of a second intensity through a variable density pattern mask, said first intensity being related to said thickness of the resist layer in said first region, said second intensity being related to said thickness of the resist layer in said second region, so that when developed said resist layer has a uniform height over said first and second regions.
A process for planarizing a surface of a semiconductor wafer which includes a first region with multiple deep trenches and a second region apart from said first region, said process including the steps of:
- coating said wafer with a resist layer whose thickness is greater over said second region than over said first region;
- aligning a mask with the resist layer, the mask having a variable density pattern having densities related to said thicknesses of the resist layer in said first and second regions;
- and
- exposing said first region with radiation of a first intensity and exposing said second region with radiation of a second intensity through the variable density pattern mask, so that when developed said resist layer has a uniform height over said first and second regions.
Dependencies are inferred from the claim text.