US4975141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser ablation for plasma etching endpoint detection
Assignee: International Business Machines Corp
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Filing: 1990-03-30
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Granted: 1990-12-04
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Expires: 2010-03-30
Abstract
Abstract A method for detecting the endpoint in an etching process including the steps of: providing a structure to be etched including at least a first layer of material overlying a second layer of material; ablating an aperture in the first layer using a beam of coherent electromagnetic radiation so as to expose a portion of the second layer; exposing the structure to an etchant for etching the second layer; and monitoring the second layer using the ablated aperture so as to detect an endpoint for the etching process.
Inventors
- 👤 Nancy A. Greco
- 👤 Joseph P. Nogay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:59
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0683; Y; Y10; Y10S; Y10S438/00; Y10S438/94
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
79 words
A method comprising the steps of: providing a structure to be etched including at least a first layer of material overlying a second layer of material; ablating an aperture in said first layer using a beam of coherent electromagnetic radiation so as to expose a portion of said second layer; exposing said structure to an etchant for etching said second layer; and monitoring said second layer using said aperture so as to detect an endpoint for said etching process.
Claim 2
Independent Claim
79 words
A method comprising the steps of: providing a structure to be etched including at least a first layer of material overlying a second layer of material; ablating an aperture in said first layer using a beam of coherent electromagnetic radiation so as to expose a portion of said second layer; exposing said structure to an etchant for etching said second layer; and monitoring said second layer using said aperture so as to detect an endpoint for said etching process.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said monitoring step includes the step of directing a second beam of electromagnetic radiation through said aperture.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein said ablating and monitoring step are performed using a single laser.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein said ablating and monitoring steps are performed using an excimer laser.
Claim 6
Dependent Claim
22 words
The method of claim 2 wherein said monitoring step includes monitoring the interference fringes contained in a reflection of said second beam.
Claim 7
Dependent Claim
28 words
The method of claim 1 wherein said ablating step is performed with said structure disposed in an etching chamber before an etchant is introduced into said etching chamber.
Claim 8
Dependent Claim
12 words
The method of claim 6 wherein said etchant comprises a chemical etchant.
Claim 9
Dependent Claim
12 words
The method of claim 7 wherein said etchant comprises a plasma etchant.
Claim 10
Dependent Claim
22 words
The method of claim 1 wherein: said first layer comprises a photoresist; and said second layer comprises an insulator or a conductor.
Claim 11
Dependent Claim
78 words
Apparatus for detecting an endpoint while etching a structure including at least a first layer of material overlying a second layer of material, said apparatus comprising: means including a beam of coherent electromagnetic radiation for ablating an aperture in said first layer so as to expose a portion of said second layer; means for etching said second layer; and means using said aperture for monitoring said second layer so as to detect an endpoint for said etching means.
Claim 12
Dependent Claim
78 words
Apparatus for detecting an endpoint while etching a structure including at least a first layer of material overlying a second layer of material, said apparatus comprising: means including a beam of coherent electromagnetic radiation for ablating an aperture in said first layer so as to expose a portion of said second layer; means for etching said second layer; and means using said aperture for monitoring said second layer so as to detect an endpoint for said etching means.
Claim 13
Dependent Claim
23 words
The apparatus of claim 10 wherein said monitoring means includes means for directing a second beam of coherent electromagnetic radiation through said aperture.
Claim 14
Dependent Claim
15 words
The apparatus of claim 11 wherein said ablating and monitoring means share a common laser.
Claim 15
Dependent Claim
16 words
The apparatus of claim 12 wherein said ablating and monitoring means each include an excimer laser.
Claim 16
Dependent Claim
25 words
The apparatus of claim 11 wherein said monitoring means includes means for monitoring the interference fringes contained in a reflection of said second light beam.
Claim 17
Dependent Claim
39 words
The apparatus of claim 11 wherein said monitoring means includes: a detector for converting a reflection of said second beam to an electrical signal; and means for monitoring a selected property of said electrical signal to detect said endpoint.
Claim 18
Dependent Claim
41 words
The apparatus of claim 11 and further including: an etching chamber surrounding said structure; and a window disposed in said chamber transparent to said beam of coherent electromagnetic radiation; such that said ablating and monitoring means are operable through said window.
Claim 19
Dependent Claim
12 words
The method of claim 16 wherein said etchant comprises a chemical etchant.
Claim 20
Dependent Claim
12 words
The method of claim 17 wherein said etchant comprises a plasma etchant.
Claim 21
Dependent Claim
22 words
The apparatus of claim 10 wherein: said first layer comprises a photoresist; and said second layer comprises an insulator or a conductor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-03 | 1994-06-04 | 1994-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-03 | 1998-06-04 | 1998-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-03 | 2002-06-04 | 2002-12-04 | $7700.00 | Window Closed / Lapsed |