Sidewall spacer with controlled geometry
AssigneeInternational Business Machines Corporation
InventorsJoel P. DE SOUZA, Yun Seog LEE, Devendra K. SADANA
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Abstract
Embodiments herein describe techniques for forming sidewalls on vertical structures on a semiconductor substrate. In one embodiment, the semiconductor substrate includes a first layer (e.g., a conductive layer such as an electrode) on which a second layer (e.g., an insulator) is disposed. An undercut etch is performed which selectively etches the sides of the material in the first layer but not the material in the second layer. A conformal deposition process is used to deposit the material of the sidewall into the undercut regions. Further etches can be performed to shape the sidewalls disposed on the sides of the material in the first layer.
Claims20
A method, comprising:
- providing a first layer directly contacting a first side of a second layer and a substrate directly contacting a second side of the second layer, wherein the first side is opposite the second side, and wherein a material in the first layer is different than a material in the second layer;
- selectively etching the material of the second layer to form an undercut region in the second layer;
- filling the undercut region with an insulative material using a conformal deposition process;
- and
- etching the insulative material to form at least one sidewall spacer in the second layer, wherein the at least one sidewall spacer includes the undercut region.
A method, comprising:
- providing a dielectric layer directly contacting a first side of a conductor and a substrate directly contacting a second side of the conductor, wherein the first side is opposite the second side;
- selectively etching the conductor to form an undercut region;
- filling the undercut region with a first material using a conformal deposition process;
- and
- etching the first material to form at least one sidewall spacer contacting the conductor, wherein the at least one sidewall spacer includes the undercut region.
A method, comprising:
- providing a first layer directly contacting a first side of a second layer and a substrate directly contacting a second side of the second layer, wherein the first side is opposite the second side, and wherein a material in the first layer is different than a material in the second layer;
- etching the material of the second layer, but not the material of the first layer, to form respective undercut regions on third and fourth sides of the material in the second layer;
- filling the respective undercut regions with an oxide material using a conformal deposition process;
- and
- etching the oxide material to form two sidewall spacers in the second layer, wherein the two sidewall spacers include the respective undercut regions.
Dependencies are inferred from the claim text.