Patent US3883947A successfully refreshed from Google Patents.
US3883947A
Expired / Lapsed
US
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Method of making a thin film electronic circuit unit
Assignee: Robert Bosch GmbH
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Filing: 1974-01-28
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Granted: 1975-05-20
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Expires: 1994-01-28
Abstract
Abstract An insulating substrate is first coated with a film of tantalum. Then either a layer of copper or two layers of copper separated by a diffusion barrier layer of iron, nickel or cobalt are applied by sputtering to metallize the surface. With a photolithographic mask to protect the circuit and component pattern, the copper and tantalum are etched to bare the substrate. Then with a screen printed mask, the copper is selectively etched over resistor and capacitor regions, and the tantalum there is partially oxidized, the copper conductors and contact areas being protected. A soft solder is then applied to the copper, but does not stick to the oxide.
Inventors
- 👤 Gunter Kruger
- 👤 Helmut Baum
- 👤 Manfred Widmaier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:29
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D86/00; H10D86/01; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099; Y10T29/49117; Y10T29/49124; Y10T29/49155; Y10T29/49156
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
231 words
A METHOD OF MANUFACTURING A THIN FILM ELECTRONIC CIRCUIT UNIT OF LAMINATE STRUCTURE COMPRISING THE STEPS OF: APPLYING A FILM OF VALVE METAL OVER THE ENTIRE SURFACE OF AN INSULATING SUBSTRATE: APPLYING A THREE-LAYER METALLIZATION FILM OVER THE ENTIRE SURFACE OF SAID FILM OF VALVE METAL BY SUCCESIVELY SPUTTERING THEREON A FIRST LAYER OF COPPER, AN INTERMEDIATE LAYER OF A DIFFUSION BARRIER METAL AND A SECOND LAYER OF COPPER APPLYING A FIRST MASK TO DEFINE THE TOTALITY OF A FIRST AND SECOND PATTERN, SAID FIRST AND SECOND PATTERNS COMMUNICATING TOGETHER IN AT LEAST ONE LOCATION; ETCHING SAID THREE-LAYER METALLIZATION FILM AND SAID VALVE METAL FILM AWAY THROUGH GAPS OF SAID FIRST MASK THEREBY LEAVING ABOUT SAID FILMS IN SAID FIRST AND SECOND PATTERNS; REMOVING SAID FIRST MASK; APPLYING A SECOND MASK TO PROTECT SAID SECOND PATTERN; ETCHING SAID THREE-LAYER METALLIZATION FILM, BUT NOT SAID VALVE METAL FIL,, OF SAID FIRST PATTERN WITH A SELCTIVE ETCHANT TO EXPOSE SAID VALVE METAL FILM OF SAID FIRST PATTERN; PARTIALLY OXIDIZING ANODIACALLY SAID VALVE METAL FILM OF SAID FIRST PATTERN, AND THEREAFTER REMOVING SAID SECOND MASK; AND DIPPING THE SURFACE OF SAID SUBSTRATE WHICH BEARS THE AFORESAID FILMS AND PATTERNS IN LIQUID LEAS-TIN SOLDER, SAID SOLDER ADHERING, AS THE RESULT OF SUCH DIPPING, TO THE THREE-LAYER METALLIZATION FILM OF SAID SECOND PATTERN BUT NOT ADHERING TO SAID OXIDIZED VALVE METAL FILM NOR TO SAID SUBSTRATE.
Claim 2
Independent Claim
231 words
A METHOD OF MANUFACTURING A THIN FILM ELECTRONIC CIRCUIT UNIT OF LAMINATE STRUCTURE COMPRISING THE STEPS OF: APPLYING A FILM OF VALVE METAL OVER THE ENTIRE SURFACE OF AN INSULATING SUBSTRATE: APPLYING A THREE-LAYER METALLIZATION FILM OVER THE ENTIRE SURFACE OF SAID FILM OF VALVE METAL BY SUCCESIVELY SPUTTERING THEREON A FIRST LAYER OF COPPER, AN INTERMEDIATE LAYER OF A DIFFUSION BARRIER METAL AND A SECOND LAYER OF COPPER APPLYING A FIRST MASK TO DEFINE THE TOTALITY OF A FIRST AND SECOND PATTERN, SAID FIRST AND SECOND PATTERNS COMMUNICATING TOGETHER IN AT LEAST ONE LOCATION; ETCHING SAID THREE-LAYER METALLIZATION FILM AND SAID VALVE METAL FILM AWAY THROUGH GAPS OF SAID FIRST MASK THEREBY LEAVING ABOUT SAID FILMS IN SAID FIRST AND SECOND PATTERNS; REMOVING SAID FIRST MASK; APPLYING A SECOND MASK TO PROTECT SAID SECOND PATTERN; ETCHING SAID THREE-LAYER METALLIZATION FILM, BUT NOT SAID VALVE METAL FIL,, OF SAID FIRST PATTERN WITH A SELCTIVE ETCHANT TO EXPOSE SAID VALVE METAL FILM OF SAID FIRST PATTERN; PARTIALLY OXIDIZING ANODIACALLY SAID VALVE METAL FILM OF SAID FIRST PATTERN, AND THEREAFTER REMOVING SAID SECOND MASK; AND DIPPING THE SURFACE OF SAID SUBSTRATE WHICH BEARS THE AFORESAID FILMS AND PATTERNS IN LIQUID LEAS-TIN SOLDER, SAID SOLDER ADHERING, AS THE RESULT OF SUCH DIPPING, TO THE THREE-LAYER METALLIZATION FILM OF SAID SECOND PATTERN BUT NOT ADHERING TO SAID OXIDIZED VALVE METAL FILM NOR TO SAID SUBSTRATE.
Claim 3
Dependent Claim
38 words
A method as defined in claim 1 in which said second mask is applied by a screen printing method and in which said second mask is adapted to serve both as an etching mask and a oxidation mask.
Claim 4
Dependent Claim
64 words
A method as defined in claim 2 in which after the step of selectively etching copper while leaving said valve metal and before the step of oxidation said substrate and the layers thereon are heated to a temperature in the neighborhood of 130*C adapted to cause said second mask to flow down over the edges of the unetched metallization film of said second pattern.
Claim 5
Dependent Claim
45 words
A method as defined in claim 1 in which at least a portion of the oxidized part of said valve metal film is coated prior to the solder dip with a metallic layer to form a capacitor and a contact connection to said metallic layer.
Claim 6
Dependent Claim
50 words
A method as defined in claim 1 in which the step of applying a three-layer metallization film is carried out by sputtering an intermediate layer of a metal selected from the group consisting of iron, cobalt and nickel between the application by sputtering of the first and second copper layers.
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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |