Patent US4081653A successfully refreshed from Google Patents.
US4081653A
Expired / Lapsed
US
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Removal of thin films from substrates by laser induced explosion
Assignee: AT&T Inc
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Filing: 1976-12-27
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Granted: 1978-03-28
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Expires: 1996-12-27
Abstract
Abstract Selected portions of a thin film coating of metal are removed from an insulative substrate by directing a coherent beam of light energy from a laser at the coating, to heat the coating and cause the evaporation and entrapment of the substrate material at the coating-substrate interface. A positive pressure builds up at the interface resulting in an explosion which removes the coating material.
Inventors
- 👤 Jackson Chik-Yun Koo
- 👤 Vincent Joseph Zaleckas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:52
CPC Classifications
B; B23; B23K; B23K26/00; B23K26/02; B23K26/06; B23K26/064; B23K26/066; B23K26/0661; B23K26/009; B23K26/36; B23K26/361; H; H05; H05K; H05K3/00; H05K3/02; H05K3/027; H05K2201/00; H05K2201/01; H05K2201/0104; H05K2201/0112; H05K2203/00; H05K2203/05; H05K2203/0548; H05K2203/056; H05K2203/10; H05K2203/107; H05K2203/13; H05K2203/1377; H05K2203/1383; H05K3/10; H05K3/18; H05K3/181; Y; Y10; Y10S; Y10S438/00; Y10S438/94
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
82 words
A method for the removal of a metallic thin film coating from a substrate, comprising the steps of: directing a beam of radiant energy to heat the thin film coating to a temperature below the melting temperature of the coating material and above the vaporization temperature of the substrate to heat and cause vaporization of the substrate at the thin film-substrate interface; and entrapping the vapors at said interface to induce an explosion to remove the thin film coating from the substrate.
Claim 2
Independent Claim
82 words
A method for the removal of a metallic thin film coating from a substrate, comprising the steps of: directing a beam of radiant energy to heat the thin film coating to a temperature below the melting temperature of the coating material and above the vaporization temperature of the substrate to heat and cause vaporization of the substrate at the thin film-substrate interface; and entrapping the vapors at said interface to induce an explosion to remove the thin film coating from the substrate.
Claim 3
Dependent Claim
18 words
The method as set forth in claim 1, wherein: the beam of radiant energy is a laser beam.
Claim 4
Dependent Claim
32 words
The method as set forth in claim 1, wherein: the thin film coating is copper and has a thickness between 200 and 500 angstroms and has a melting temperature of 1,083° C.
Claim 5
Dependent Claim
18 words
The method as set forth in claim 3, wherein the substrate has a vaporization temperature of 200° C.
Claim 6
Independent Claim
106 words
A method of selectively removing portions of a metallic thin film coating from a substrate, comprising the steps of: placing an apertured, heat resistant mask on the coated substrate; raster scanning the masked, coated substrate with a coherent laser beam focused at the thin film coating to heat portions of the coating which are exposed through the apertures to a temperature below the melting temperature of the coating material and above the vaporization temperature of the substrate at the thin film-substrate interface; and entrapping the vapors at said interface to induce an explosion to remove the selected portions of the thin film coating from the substrate.
Claim 7
Independent Claim
106 words
A method of selectively removing portions of a metallic thin film coating from a substrate, comprising the steps of: placing an apertured, heat resistant mask on the coated substrate; raster scanning the masked, coated substrate with a coherent laser beam focused at the thin film coating to heat portions of the coating which are exposed through the apertures to a temperature below the melting temperature of the coating material and above the vaporization temperature of the substrate at the thin film-substrate interface; and entrapping the vapors at said interface to induce an explosion to remove the selected portions of the thin film coating from the substrate.
Claim 8
Dependent Claim
38 words
The method of selectively removing portions of a thin film coating from a substrate as set forth in claim 5, which further comprises: interposing a transparent film between the apertured heat resistant mask and the thin film coating.
Claim 9
Dependent Claim
32 words
The method as set forth in claim 5, wherein the thin film coating is copper and has a thickness between 200 and 500 angstroms and has a melting temperature of 1,083° C.
Claim 10
Dependent Claim
18 words
The method as set forth in claim 7, wherein the substrate has a vaporization temperature of 200° C.
Claim 11
Independent Claim
138 words
A method of fabricating a printed circuit board by selectively removing portions of a metallic thin film coating from an insulative substrate, comprising the steps of: (a) placing a transparent film over the metallic thin film coating; (b) further placing a metallic, apertured heat resistant mask on the tranparent film; (c) raster scanning the mask with a coherent laser beam focused at the metallic thin film coating to heat portions of the coating, which are exposed through the apertures, to a temperature below the melting temperature of the metallic thin film coating and above the vaporization temperature of the dielectric substrate at the metallic thin film-insulative substrate interface; and (d) entrapping the vapors of the substrate at said interface to induce an explosion to remove the selected portions of the metallic thin film coating from the insulative substrate.
Claim 12
Independent Claim
138 words
A method of fabricating a printed circuit board by selectively removing portions of a metallic thin film coating from an insulative substrate, comprising the steps of: (a) placing a transparent film over the metallic thin film coating; (b) further placing a metallic, apertured heat resistant mask on the tranparent film; (c) raster scanning the mask with a coherent laser beam focused at the metallic thin film coating to heat portions of the coating, which are exposed through the apertures, to a temperature below the melting temperature of the metallic thin film coating and above the vaporization temperature of the dielectric substrate at the metallic thin film-insulative substrate interface; and (d) entrapping the vapors of the substrate at said interface to induce an explosion to remove the selected portions of the metallic thin film coating from the insulative substrate.
Claim 13
Dependent Claim
48 words
The method of fabricating a printed circuit board as set forth in claim 9, wherein: the metallic thin film is copper having a thickness between 200 and 500 angstroms and has a melting temperature of 1,083° C; and the insulative substrate has a vaporization temperature of 200° C.
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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) | 1981-03-27 | 1981-09-26 | 1982-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-27 | 1985-09-26 | 1986-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-27 | 1989-09-26 | 1990-03-28 | $7700.00 | Window Closed / Lapsed |