Patent US3930975A successfully refreshed from Google Patents.
US3930975A
Expired / Lapsed
US
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Sputtering method for producing solder-fast copper layers
Assignee: Robert Bosch GmbH
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Filing: 1974-10-10
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Granted: 1976-01-06
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Expires: 1994-10-10
Abstract
Abstract Copper is sputtered onto a substrate to make a solder-fast contact layer by carrying out the sputtering in a discharge of a monatomic gas containing 0.5 to 16% of air, nitrogen or oxygen which reduces the conductivity of the copper layer, but makes it resistant to alloying with a solution in solder, to an extent comparable with the results obtained by the provision of intermediate diffusion barrier layers. Best results are obtained in an argon discharge in the presence of an admixture of nitrogen or air between 2 and 4% by volume. The solder-wetting properties are not impaired.
Inventors
- 👤 Gert Siegle
- 👤 Hans Lutz
- 👤 Helmut Adam
- 👤 Erhard Gossl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:15
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/0021; C23C14/0036; H; H05; H05K; H05K1/00; H05K1/02; H05K1/09; H05K3/00; H05K3/10; H05K3/14; H05K3/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
117 words
Method of producing a solder-fast thin film circuit unit having copper layer connection paths and contact patches which comprises the step of cathodically sputtering copper onto a substrate in a circuit pattern including contact patches, said sputtering being carried out in a gas discharge medium consisting of a monatomic gas with an admixture of between 0.5 and 16% by volume of a normally predominantly diatomic atmospheric gas under conditions in which said atmospheric gas is taken up in part in said copper layer and reduces the conductivity of the deposited copper to between 7 and 40% of the conductivity of a pure copper layer, whereby contact patches capable of being soldered and of withstanding soldering are produced.
Claim 2
Dependent Claim
117 words
Method of producing a solder-fast thin film circuit unit having copper layer connection paths and contact patches which comprises the step of cathodically sputtering copper onto a substrate in a circuit pattern including contact patches, said sputtering being carried out in a gas discharge medium consisting of a monatomic gas with an admixture of between 0.5 and 16% by volume of a normally predominantly diatomic atmospheric gas under conditions in which said atmospheric gas is taken up in part in said copper layer and reduces the conductivity of the deposited copper to between 7 and 40% of the conductivity of a pure copper layer, whereby contact patches capable of being soldered and of withstanding soldering are produced.
Claim 3
Dependent Claim
28 words
Method as defined in claim 1 in which said substrate is a substrate which has been previously provided with constituting a surface layer a resistance to electrical conductivity.
Claim 4
Dependent Claim
26 words
Method as defined in claim 2 in which said copper layer is sputtered without any intermediate sputtering of an interleaved layer functioning as a diffusion barrier.
Claim 5
Dependent Claim
21 words
Method as defined in claim 1 in which said monatomic gas is argon and in which said atmospheric gas is nitrogen.
Claim 6
Dependent Claim
19 words
Method as defined in claim 1 in which said monatomic gas is argon and said atmospheric gas is oxygen.
Claim 7
Dependent Claim
19 words
Method as defined in claim 1 in which said monatomic gas is argon and said atmospheric gas is air.
Claim 8
Dependent Claim
24 words
Method as defined in claim 1 in which the amount of said admixture of an atmospheric gas is between 2 and 4% by volume.
Claim 9
Dependent Claim
18 words
Method as defined in claim 1 in which the copper sputtering step employs a pure copper target cathode.
Claim 10
Dependent Claim
24 words
Method as defined in claim 1 in which sputtering is carried out under a potential between 3 and 8 kV. in a diode apparatus.
Claim 11
Dependent Claim
14 words
Method as defined in claim 9 in which said potential is approximately 6 kV.
Claim 12
Dependent Claim
36 words
Method as defined in claim 1 in which during the cathode sputtering step a gas flow through the sputtering vessel is provided of a magnitude, reduced to normal conditions, between 0.1 and 3 liters per hour.
Claim 13
Dependent Claim
30 words
Method as defined in claim 11 in which said gas flow is approximately 1 liter per hour and the cathode surface has an area of approximately 1,000 cm 2 .
Claim 14
Dependent Claim
30 words
Method as define in claim 1 in which the sputtering step is carried out for such a period that the copper layer produced has a thickness of about 0.5 μm.
Claim 15
Dependent Claim
23 words
Method as defined in claim 1 in which monatomic gas is argon and said atmospheric gas is a mixture of oxygen and nitrogen.
Claim 16
Dependent Claim
129 words
Method of producing a solder-fast thin film unit having a resistive layer and a copper layer thereon which comprises the step of cathodically sputtering copper onto a substrate which has previously been provided with a surface layer of a material selected from the group which consists of tantalum nitride, tantalum oxynitride and mixtures of tantalum and aluminum, said step of sputtering copper being carried out in a gas discharge medium consisting of a monatomic gas with an admixture of between 0.5 and 16% by volume of a normally predominantly diatomic atmospheric gas under conditions in which said atmospheric gas is taken up in part in said copper layer and reduces the conductivity of the deposited copper to between 7 and 40% of the conducitivity of a pure copper layer.
Claim 17
Dependent Claim
129 words
Method of producing a solder-fast thin film unit having a resistive layer and a copper layer thereon which comprises the step of cathodically sputtering copper onto a substrate which has previously been provided with a surface layer of a material selected from the group which consists of tantalum nitride, tantalum oxynitride and mixtures of tantalum and aluminum, said step of sputtering copper being carried out in a gas discharge medium consisting of a monatomic gas with an admixture of between 0.5 and 16% by volume of a normally predominantly diatomic atmospheric gas under conditions in which said atmospheric gas is taken up in part in said copper layer and reduces the conductivity of the deposited copper to between 7 and 40% of the conducitivity of a pure copper layer.
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) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |