US5147499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removal of residues remaining after etching polysilicon layer in formation of integrated circuit structure
Assignee: Applied Materials Inc
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Filing: 1991-07-24
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Granted: 1992-09-15
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Expires: 2011-07-24
Abstract
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 hydroxide/peroxide solution to remove the residues of polymerized silicon/oxide-containing material, without undercutting the remaining polysilicon.
Inventors
- 👤 Chester Szwejkowski
- 👤 Ian S. Latchford
- 👤 Isamu Namose
- 👤 Kazumi Tsuchida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:47
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/20; H10P70/27; H10P70/273; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; Y; Y10; Y10S; Y10S438/00; Y10S438/963
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
82 words
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 hydroxide/peroxide solution to remove said residues of polymerized silicon/oxide-containing material with minimum damage to exposed oxide portions on the structure.
Claim 2
Dependent Claim
82 words
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 hydroxide/peroxide solution to remove said residues of polymerized silicon/oxide-containing material with minimum damage to exposed oxide portions on the structure.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein said aqueous hydroxide/peroxide solution comprises hydrogen peroxide and a hydroxide selected from the class consisting of ammonium hydroxide and potassium hydroxide.
Claim 4
Dependent Claim
20 words
The process of claim 2 wherein said aqueous hydroxide/peroxide solution comprises an aqueous solution of hydrogen peroxide and ammonium hydroxide.
Claim 5
Dependent Claim
20 words
The process of claim 2 wherein said aqueous hydroxide/peroxide solution comprises an aqueous solution of hydrogen peroxide and potassium hydroxide.
Claim 6
Dependent Claim
30 words
The process of claim 3 wherein said aqueous hydroxide/peroxide solution has a concentration, in volume parts, of about 1 part hydroxide, about 2 parts peroxide, and about 7 parts water.
Claim 7
Dependent Claim
29 words
The process of claim 5 wherein said treatment with said aqueous hydroxide/peroxide solution is carried out for a time period of from about 5 seconds to about 15 minutes.
Claim 8
Dependent Claim
29 words
The process of claim 6 wherein said treatment with said aqueous hydroxide/peroxide solution is carried out for a time period of from about 30 seconds to about 60 seconds.
Claim 9
Dependent Claim
32 words
The process of claim 6 wherein said treatment in said aqueous hydroxide/peroxide solution is carried out while maintaining said solution at a temperature ranging from about 50° C. to about 70° C.
Claim 10
Dependent Claim
33 words
The process of claim 6 wherein said treatment in said aqueous hydroxide/peroxide solution is carried out while maintaining said hydroxide solution at a temperature ranging from about 55° C. to about 65° C.
Claim 11
Dependent Claim
29 words
The process of claim 6 wherein said treatment in said aqueous hydroxide/peroxide solution is carried out while maintaining said solution at a temperature of about 60° C. ±2° C.
Claim 12
Dependent Claim
28 words
The process of claim 6 wherein said integrated circuit structure is RIE etched prior to said step of treating said integrated circuit structure in said aqueous hydroxide/peroxide solution.
Claim 13
Dependent Claim
50 words
The process of claim 1 wherein said treatment of said integrated circuit structure with said aqueous hydroxide/peroxide solution further comprises treating said integrated circuit structure for from about 30 to 60 seconds with said aqueous hydroxide/peroxide solution maintained at a temperature of from about 55° C. to about 65° C.
Claim 14
Dependent Claim
123 words
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 60 seconds with an aqueous hydroxide/peroxide solution having a volume concentration of 1 part ammonium hydroxide, 2 parts hydrogen peroxide, and 7 parts water, and a temperature of from about 50° C. to about 70° C. to remove said polymerized silicon/oxide-containing sidewall residues with minimum damage to exposed silicon oxide portions of said structure.
Claim 15
Dependent Claim
123 words
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 60 seconds with an aqueous hydroxide/peroxide solution having a volume concentration of 1 part ammonium hydroxide, 2 parts hydrogen peroxide, and 7 parts water, and a temperature of from about 50° C. to about 70° C. to remove said polymerized silicon/oxide-containing sidewall residues with minimum damage to exposed silicon oxide portions of said structure.
Claim 16
Dependent Claim
26 words
The process of claim 13 wherein said treatment with said aqueous hydroxide/peroxide solution is carried out for a period of from about 30 to 60 seconds.
Claim 17
Dependent Claim
33 words
The process of claim 13 wherein said treatment in said aqueous hydroxide/peroxide solution is carried out while maintaining said hydroxide solution at a temperature ranging from about 55° C. to about 65° C.
Claim 18
Dependent Claim
29 words
The process of claim 13 wherein said treatment in said aqueous hydroxide/peroxide solution is carried out while maintaining said solution at a temperature of about 60° C. ±2° C.
Claim 19
Dependent Claim
23 words
The process of claim 13 wherein the concentration of said hydrogen peroxide, before mixing with said hydroxide and water, is about 30 volume%.
Claim 20
Dependent Claim
27 words
The process of claim 13 wherein the concentration of said hydroxide, before mixing with said hydrogen peroxide and water, is from about 28 to about 30 volume%.
Claim 21
Dependent Claim
146 words
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 60 seconds with an aqueous hydroxide/peroxide solution consisting of ammonium hydroxide, hydrogen peroxide, and water having a volume concentration of about 1 part hydroxide, about 2 parts peroxide, and about 7 parts water, and a temperature of from about 55° C. to about 65° C. to remove said residues of said polymerized silicon/oxide-containing material without damaging said exposed silicon oxide portions of said structure.
Claim 22
Dependent Claim
146 words
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 60 seconds with an aqueous hydroxide/peroxide solution consisting of ammonium hydroxide, hydrogen peroxide, and water having a volume concentration of about 1 part hydroxide, about 2 parts peroxide, and about 7 parts water, and a temperature of from about 55° C. to about 65° C. to remove said residues of said polymerized silicon/oxide-containing material without damaging said exposed silicon oxide portions of said structure.
References Cited (Backward Citations)
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