US4752668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for laser removal of excess material from a semiconductor wafer
Assignee: International Business Machines Corp
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Filing: 1986-04-28
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Granted: 1988-06-21
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Expires: 2006-04-28
Abstract
Abstract A system for removing excess material from a semiconductor wafer employs an excimer laser for ablative photocomposition. A wafer is positioned on an X-Y stage that is computer controlled to position the wafer at points where the laser may be focused to remove excess material whether over alignment marks or identified contamination. The laser passes through a vacuum chamber which by generating an inward laminar flow constrains any particulate contamination resulting from the ablative photodecomposition from spreading. This material is removed by the vacuum system.
Inventors
- 👤 Michael G. Rosenfield
- 👤 David E. Seeger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:53
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/42; B; B23; B23K; B23K26/00; B23K26/14; B23K26/1462; G03F1/00; G03F1/68; G03F1/72
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
91 words
A system for removing excess material from a semiconductor wafer comprising: an X-Y stage for supporting said wafer; a vacuum chamber disposed above said wafer and movable vertically with respect to said stage to maintain said chamber at a controlled distance from said wafer; an excimer laser; means to focus a beam from said excimer laser through said vacuum chamber onto said wafer; and means to move said stage such that said laser is positioned to remove said excess material by ablative photodecomposition and said vacuum removes any resulting particulate contamination.
Claim 2
Independent Claim
91 words
A system for removing excess material from a semiconductor wafer comprising: an X-Y stage for supporting said wafer; a vacuum chamber disposed above said wafer and movable vertically with respect to said stage to maintain said chamber at a controlled distance from said wafer; an excimer laser; means to focus a beam from said excimer laser through said vacuum chamber onto said wafer; and means to move said stage such that said laser is positioned to remove said excess material by ablative photodecomposition and said vacuum removes any resulting particulate contamination.
Claim 3
Dependent Claim
15 words
The system of claim 1 further comprising computer means to control movement of said stage.
Claim 4
Dependent Claim
19 words
The system of claim 2 further comprising a shutter blocking said beam, and said computer means controlling said shutter.
Claim 5
Dependent Claim
37 words
The system of claim 1, wherein said means to focus comprises a mirror to direct said beam from said excimer laser onto said wafer, a mask and, a condenser lens to focus said beam onto said wafer.
Claim 6
Dependent Claim
48 words
The system of claim 1, wherein said vacuum chamber includes a window for optically passing said beam and, a converging nozzle proximate to the surface of said wafer such that a zone of laminar flow is created around the excess material to sweep particulate contamination into said nozzle.
Claim 7
Dependent Claim
21 words
The system of claim 1, wherein said vacuum chamber is maintained at a controlled distance of 20-100 microns above said wafer.
Claim 8
Dependent Claim
20 words
The system of claim 5, wherein said vacuum chamber nozzle has a diameter of in the range of 50-500 microns.
Claim 9
Dependent Claim
22 words
The system of claim 1 further comprising alignment optics to optically sight said wafer for determining any rotational misalignment of said wafer.
Claim 10
Dependent Claim
28 words
The system of claim 1, wherein said vacuum chamber is maintained at a distance above said wafer to contain debris and said nozzle does not strike said stage.
Claim 11
Independent Claim
85 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; positioning a vacuum chamber above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; and removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber, wherein said excess material comprises a photoresist material that can be ablated without damaging the underlying substrate.
Claim 12
Independent Claim
85 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; positioning a vacuum chamber above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; and removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber, wherein said excess material comprises a photoresist material that can be ablated without damaging the underlying substrate.
Claim 13
Independent Claim
91 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; positioning a vacuum chamber above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber; and moving said stage and actuating said laser to remove excess material at a position removed from the location of excess material first removed.
Claim 14
Independent Claim
91 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; positioning a vacuum chamber above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber; and moving said stage and actuating said laser to remove excess material at a position removed from the location of excess material first removed.
Claim 15
Dependent Claim
22 words
The method of claim 11, wherein said excess material comprises a photoresist material then can be ablated without damaging the underlying substrate.
Claim 16
Dependent Claim
14 words
The method of claim 12, wherein said photoresist covers alignment marks on said wafer.
Claim 17
Dependent Claim
33 words
The method of claim 10 further comprising the steps of moving said stage and actuating said laser to remove excess material at a position removed from the location of excess material first removed.
Claim 18
Dependent Claim
20 words
The method of claim 10 further comprising the step of moving said vacuum chamber vertically with respect to said wafer.
Claim 19
Dependent Claim
20 words
The method of claim 15, wherein said vacuum chamber is maintained at a distance of 20-100 microns above said wafer.
Claim 20
Dependent Claim
15 words
The method of claim 11, wherein said excess material is ablated without damaging the wafer.
Claim 21
Dependent Claim
27 words
The method of claim 15, wherein said vacuum chamber is maintained at a distance such that debris is contained and vacuum chamber does not contact said stage.
Claim 22
Independent Claim
88 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; moving a vacuum chamber vertically with respect to said wafer to position said vacuum chamber above said wafer at a distance of 20-100 microns above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; and removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber.
Claim 23
Independent Claim
88 words
A method of removing excess material from a semiconductor wafer comprising: supporting said wafer on a horizontally movable stage; moving a vacuum chamber vertically with respect to said wafer to position said vacuum chamber above said wafer at a distance of 20-100 microns above said wafer; actuating an excimer laser and directing a beam through said vacuum chamber onto said excess material for removal thereof by ablative photodecomposition; and removing any contamination by vacuum action while preventing any spread thereof by inward laminar airflow toward said vacuum chamber.
References Cited (Backward Citations)
US3569660A
Cited
US3866398A
Cited
US4370175A
Cited
US4504726A
Cited
US4532401A
Cited
US4577958A
Cited
US4414059A
Cited
US4564739A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |