US4350562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for etching semiconductor wafers on one side
Assignee: Siemens AG
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Filing: 1981-06-18
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Granted: 1982-09-21
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Expires: 2001-06-18
Abstract
Abstract Etching a semiconductor wafer on one side by suspending the wafer on a rotating gas cushion with the wafer surface not to be etched facing the gas cushion with the other wafer surface exposed for etching. The exposed surface is sprayed with etchant and centrifuged at the same time. Subsequently, the etched surface is sprayed with rinsing agent and then centrifuged dry.
Inventors
- 👤 Bonu Bonu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:53
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/126; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
74 words
Method for etching semiconductor wafers on one side, which comprises suspending a semiconductor wafer to be etched on a rotating gas cushion with the semiconductor wafer surface not to be etched facing the rotating gas cushion while the semiconductor wafer surface to be etched is free, and spraying the free semiconductor surface with etchant, said wafer in contact with the rotating gas cushion rotating and moving the etchant thereon outward away from the center.
Claim 2
Dependent Claim
74 words
Method for etching semiconductor wafers on one side, which comprises suspending a semiconductor wafer to be etched on a rotating gas cushion with the semiconductor wafer surface not to be etched facing the rotating gas cushion while the semiconductor wafer surface to be etched is free, and spraying the free semiconductor surface with etchant, said wafer in contact with the rotating gas cushion rotating and moving the etchant thereon outward away from the center.
Claim 3
Dependent Claim
21 words
Method according to claim 1, wherein the free semiconductor surface is subsequently sprayed with a rinsing agent and then centrifuged dry.
Claim 4
Dependent Claim
13 words
Method according to claim 1, wherein the etchant is heated prior to spraying.
Claim 5
Dependent Claim
23 words
Method according to claim 1, wherein the semiconductor material is silicon, the etchant is hydrofluoric acid and the rinsing agent is deionized water.
Claim 6
Dependent Claim
46 words
Method according to claim 1, wherein the semiconductor wafer is suspended above a turntable by passing an axial gas stream through the turntable to provide said gas cushion between the turntable and the semiconductor wafer, and wherein the suspended wafer is blocked from substantial lateral movement.
Claim 7
Dependent Claim
24 words
Method according to claim 5, wherein liquid flowing off the semiconductor wafer is collected and the collected liquid pumped back for spraying the wafer.
Claim 8
Dependent Claim
53 words
Method according to claim 5 or claim 6, wherein the wafer is transported from storage by attaching the wafer by suction to a swivel arm and swiveling the arm to deposit the wafer above the turntable, and also transporting the wafer after treatment by suction by a swivel arm to a product site.
References Cited (Backward Citations)
US4165252A
Cited
US4161356A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |