Patent US5645737A successfully refreshed from Google Patents.
US5645737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wet clean for a surface having an exposed silicon/silica interface
Assignee: Micron Technology Inc
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Filing: 1996-02-21
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Granted: 1997-07-08
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Expires: 2016-02-21
Abstract
Abstract A surface having an exposed silicon/silica interface is cleaned by an HF dip, followed immediately by a rinse in citric acid, followed by a rinse in deionized water. Low pH of the citric acid significantly prevents the formation of a charge differential between the silica and silicon portions of the surface, which charge differential would otherwise cause any silica particles present to remain on the silicon portion of the surface. Surfactant properties of the citric acid help remove any silica particles from the surface. The deionized water rinse then removes the citric acid from the surfaces, leaving a very clean, low particulate surface on both the silica and silicon portions thereof, with little or no etching of the silicon portion.
Inventors
- 👤 Karl M. Robinson
- 👤 Michael A. Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:11
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15; B; B08; B08B; B08B3/00; B08B3/04; B08B3/08; C; C11; C11D; C11D7/00; C11D7/02; C11D7/04; C11D7/06; C11D7/08; H10P72/00; H10P72/04; H10P72/0402; H10P72/0406; H10P72/0411; H10P72/0414; H10P72/0416; C11D2111/00; C11D2111/10; C11D2111/14; C11D2111/22; Y; Y10; Y10S; Y10S438/00; Y10S438/906
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
43 words
A method for cleaning a surface comprising: contacting a silicon/silica interface of a surface with a hydrofluoric acid solution; and contacting said silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH less than about 4.
Claim 2
Independent Claim
43 words
A method for cleaning a surface comprising: contacting a silicon/silica interface of a surface with a hydrofluoric acid solution; and contacting said silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH less than about 4.
Claim 3
Dependent Claim
43 words
The method as defined in claim 1, further comprising, after contacting said silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH less than about 4, rinsing said silicon/silica interface of said surface in deionized water.
Claim 4
Dependent Claim
24 words
The method as defined in claim 1, wherein said hydrofluoric acid solution has a concentration within a range from about 4:1 to about 250:1.
Claim 5
Dependent Claim
23 words
The method as defined in claim 1, wherein said citric acid has a pH in a range from about 2 to about 4.
Claim 6
Independent Claim
80 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4; and rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 7
Independent Claim
80 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4; and rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 8
Dependent Claim
17 words
The method as defined in claim 5, wherein said citric acid has a pH of about 2.2.
Claim 9
Dependent Claim
24 words
The method as defined in claim 5 wherein said hydrofluoric acid solution has a concentration within the range of about 4:1 to about 250:1.
Claim 10
Dependent Claim
18 words
The method as defined in claim 7 wherein said hydrofluoric acid solution has a concentration of about 100:1.
Claim 11
Dependent Claim
37 words
The method as defined in claim 5, wherein said step of contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution comprises the step of dipping said semiconductor wafer in a hydrofluoric acid solution.
Claim 12
Dependent Claim
51 words
The method as defined in claim 5, wherein said step of contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4 comprises the step of dipping said semiconductor wafer in said citric acid.
Claim 13
Dependent Claim
51 words
The method as defined in claim 5, wherein said step of contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4 comprises spraying said exposed silicon/silica interface of said surface with citric acid.
Claim 14
Dependent Claim
49 words
The method as defined in claim 5, further comprising the step, prior to the step of contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution, of performing a chemical mechanical polishing step to expose the silicon/silica interface of the surface situated on the semiconductor wafer.
Claim 15
Dependent Claim
23 words
The method as defined in claim 5, wherein said exposed silicon/silica interface of said surface comprises a silicon surface and field oxide surface.
Claim 16
Independent Claim
105 words
A method for removing silica particles from a surface situated on a semiconductor wafer, said method including the steps of: performing a chemical mechanical polishing step to expose a silicon/silica interface on said surface situated on the semiconductor wafer; contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4; and rinsing said exposed silicon/silica interface of said surface in deionized water, whereby silica particles are removed from said surface situated on said semiconductor wafer.
Claim 17
Independent Claim
105 words
A method for removing silica particles from a surface situated on a semiconductor wafer, said method including the steps of: performing a chemical mechanical polishing step to expose a silicon/silica interface on said surface situated on the semiconductor wafer; contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4; and rinsing said exposed silicon/silica interface of said surface in deionized water, whereby silica particles are removed from said surface situated on said semiconductor wafer.
Claim 18
Dependent Claim
17 words
The method as defined in claim 14, wherein said citric acid has a pH of about 2.2.
Claim 19
Dependent Claim
23 words
The method as defined in claim 14, wherein said hydrofluoric acid solution has a concentration within the range of about 4:1 to 250:1.
Claim 20
Dependent Claim
17 words
The method as defined in claim 16, wherein said hydrofluoric acid solution has a concentration about 100:1.
Claim 21
Dependent Claim
37 words
The method as defined in claim 14, wherein said step of contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution comprises the step of dipping said semiconductor wafer in a hydrofluoric acid solution.
Claim 22
Dependent Claim
50 words
The method as defined in claim 14, wherein said step of contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4 comprises the step of dipping said semiconductor wafer in citric acid.
Claim 23
Dependent Claim
51 words
The method as defined in claim 14, wherein said step of contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant composed of citric acid having pH in the range of about 2 to 4 comprises spraying said exposed silicon/silica interface of said surface with citric acid.
Claim 24
Independent Claim
114 words
A method for cleaning a surface situated on a semiconductor wafer, said method including the steps of: (a) performing a chemical mechanical polishing step to expose a silicon/silica interface on a surface situated on the semiconductor wafer; (b) dipping said semiconductor wafer in a hydrofluoric acid solution having a concentration of about 100:1 so as to contact said exposed silicon/silica interface of said surface with said hydrofluoric acid solution; (c) dipping said semiconductor wafer in a citric acid solution having a pH of about 2.2 so as to contact said exposed silicon/silica interface of said surface with said citric acid solution; and (d) rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 25
Independent Claim
114 words
A method for cleaning a surface situated on a semiconductor wafer, said method including the steps of: (a) performing a chemical mechanical polishing step to expose a silicon/silica interface on a surface situated on the semiconductor wafer; (b) dipping said semiconductor wafer in a hydrofluoric acid solution having a concentration of about 100:1 so as to contact said exposed silicon/silica interface of said surface with said hydrofluoric acid solution; (c) dipping said semiconductor wafer in a citric acid solution having a pH of about 2.2 so as to contact said exposed silicon/silica interface of said surface with said citric acid solution; and (d) rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 26
Independent Claim
90 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: (a) contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution, wherein said exposed silicon/silica interface of said surface comprises a silica surface and an exposed edge of a silicon capacitor plate; (b) contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant; and (c) rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 27
Independent Claim
90 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: (a) contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution, wherein said exposed silicon/silica interface of said surface comprises a silica surface and an exposed edge of a silicon capacitor plate; (b) contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant; and (c) rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 28
Independent Claim
86 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution, wherein said exposed silicon/silica interface of said surface comprises a silica surface and the surface of a silicon contact plug; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant; and rinsing said exposed silicon/silica interface of said surface in deionized water.
Claim 29
Independent Claim
86 words
A method for performing a clean of a surface on a semiconductor wafer, said surface having thereon an exposed silicon/silica interface, said method including the steps of: contacting said exposed silicon/silica interface of said surface with a hydrofluoric acid solution, wherein said exposed silicon/silica interface of said surface comprises a silica surface and the surface of a silicon contact plug; contacting said exposed silicon/silica interface of said surface with an organic carboxylic acid surfactant; and rinsing said exposed silicon/silica interface of said surface in deionized water.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-07 | 2001-01-06 | 2001-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-07 | 2005-01-06 | 2005-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-07 | 2009-01-06 | 2009-07-08 | $7700.00 | Window Closed / Lapsed |