Process for removal of residues remaining after etching polysilicon layer in formation of integrated circuit structure
AssigneesApplied Materials, Inc., Seiko Epson Corporation
InventorsChester Szwejkowski, Ian S. Latchford, Isamu Namose, Kazumi Tsuchida
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Abstract
The invention comprises an improvement in the process wherein a polysilicon layer, which is formed over a step on an integrated circuit structure and masked with a photoresist, is anisotropically etched to remove the exposed portions of the polysilicon layer leaving sidewall residues of a polymerized silicon/oxide-containing material adjacent the polysilicon lines. The improvement comprises treating the integrated circuit substrate with an aqueous ammonium-containing base/peroxide solution to remove the residues of polymerized silicon/oxide-containing material, without undercutting the remaining polysilicon.
Claims19
In a process wherein a polysilicon layer, which is formed over a step on an integrated circuit structure and masked with a photoresist, is anisotropically etched to remove the exposed portions of the polysilicon layer leaving residues of a polymerized silicon/oxide-containing material adjacent the sidewalls of the masked portions of polysilicon, the improvement comprising:
- treating the integrated circuit substrate with an aqueous ammonium-containing base/peroxide solution to remove said residues of polymerized silicon/oxide-containing material with minimum damage to exposed oxide portions on the structure.
In a process wherein a polysilicon layer, which is formed over a step on an integrated circuit structure and masked with a photoresist, is anisotropically RIE etched to remove exposed portions of said polysilicon layer leaving residues of a polymerized silicon/oxide-containing material adjacent the sidewalls of the masked portions of said polysilicon layer, the improvement comprising:
- treating said integrated circuit structure for a period of time not exceeding about 10 minutes with an aqueous ammonium-containing base/peroxide solution having a volume concentration of 1 part ammonium-containing base solution, 2-4 parts hydrogen peroxide solution, and 5-7 parts additional water, and a temperature of from about 50.degree. C. to about 90.degree. C. to remove said polymerized silicon/oxide-containing sidewall residues with minimum damage to exposed silicon oxide portions of said structure.
An improved process for etching a polysilicon layer masked with a photoresist and which is formed over a step previously formed on an integrated circuit structure having exposed portion of silicon oxide thereon which comprises:
- a) anisotropically RIE etching said polysilicon layer to remove exposed portions of said polysilicon layer, leaving residues of polymerized silicon/oxide-containing material adjacent the sidewalls of said masked portions of said polysilicon layer;
- and
- b) treating said integrated circuit structure for a period of time not exceeding about 10 minutes with an aqueous ammonium-containing base/peroxide solution consisting of:
- (1) an ammonium-containing base selected from the group consisting of ammonium fluoride and ammonium hydroxide;
- (2) hydrogen peroxide;
- and
- (3) water;
- having a volume concentration of about 1 part ammonium-containing base solution, about 2-4 parts peroxide solution, and about 5-7 parts additional water, and a temperature of from about 50.degree. C. to about 90.degree. C. to remove said residues of said polymerized silicon/oxide-containing material without damaging said exposed silicon oxide portions of said structure.
Dependencies are inferred from the claim text.