US4415402A
Expired / Lapsed
US
⏱️ 0.0 years remaining
End-point detection in plasma etching or phosphosilicate glass
Assignee: Lam Research Corp
•
Filing: 1981-04-02
•
Granted: 1983-11-15
•
Expires: 2001-04-02
Abstract
Abstract A method for determining the completion of removal by plasma etching of phosphorus doped silicon dioxide from an underlying substrate.
Inventors
- 👤 Barry Gelernt
- 👤 C. Wallace Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:56
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; G; G01; G01N; G01N21/00; G01N21/62; G01N21/66; G01N21/67
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
121 words
A method for detecting end-point in the plasma etching of a phosphorous doped silicon dioxide layer coated on a substrate of single crystal silicon comprising the steps of; etching the phosphorous doped silicon dioxide from the substrate within an etching chamber with gas from the fluorinated hydrocarbon family, spectroscopically observing the gases in the etching chamber over a time interval covering the beginning and end of the etching process and within a predetermined wavelength interval, observing the presence of the phosphorous atomic line straddled by two argon atomic lines at the beginning of the etching process, observing the disappearance of said phosphorous atomic line from between said two argon atomic lines as an indication of the end of the etching process.
Claim 2
Independent Claim
121 words
A method for detecting end-point in the plasma etching of a phosphorous doped silicon dioxide layer coated on a substrate of single crystal silicon comprising the steps of; etching the phosphorous doped silicon dioxide from the substrate within an etching chamber with gas from the fluorinated hydrocarbon family, spectroscopically observing the gases in the etching chamber over a time interval covering the beginning and end of the etching process and within a predetermined wavelength interval, observing the presence of the phosphorous atomic line straddled by two argon atomic lines at the beginning of the etching process, observing the disappearance of said phosphorous atomic line from between said two argon atomic lines as an indication of the end of the etching process.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein a layer of thermal oxide is disposed between the substrate and the layer of phosphorus doped silicon dioxide.
Claim 4
Dependent Claim
24 words
A method according to claim 1 wherein a layer of aluminum is disposed between the substrate and the layer of phosphorus doped silicon dioxide.
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) | 1986-11-14 | 1987-05-16 | 1987-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-14 | 1991-05-16 | 1991-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-14 | 1995-05-16 | 1995-11-15 | $7700.00 | Window Closed / Lapsed |