Patent US3772077A successfully refreshed from Google Patents.
US3772077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor devices
Assignee: Ferranti International PLC
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Filing: 1971-04-06
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Granted: 1973-11-13
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Expires: 1991-04-06
Abstract
Abstract Aluminum of a contact for a semiconductor device is rendered solderable, or a region of the aluminum selectively is rendered solderable, by depositing from a solution of zinc oxide and a hydroxide of an alkali metal a first zinc layer, which is removed, and a second zinc layer initially having an activated surface, and then depositing a nickel layer on the activated zinc surface by reducing an acid solution of a nickel salt.
Inventors
- 👤 V Magee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:04
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/40; H10P14/46; H10P95/00; Y; Y10; Y10S; Y10S438/00; Y10S438/974; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12528
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
20 words
A method as claimed in claim 1 in which the exposed nickel surface has been soldered with a tin-based solder.
Claim 2
Dependent Claim
15 words
A method as claimed in claim 1 in which the nickel salt is nickel chloride.
Claim 3
Dependent Claim
26 words
A method as claimed in claim 1 in which the reducing agent for the nickel salt is selected from the group sodium hypophosphite and sodium borohydride.
Claim 4
Dependent Claim
39 words
A method as claimed in claim 1 further including, prior to the deposition of said first layer of zinc, covering said aluminum with an insulative layer and removing a portion of said insulative layer to expose an aluminum surface.
Claim 5
Dependent Claim
69 words
A method as claimed in claim 1 wherein said step of providing a layer of aluminum includes extending said layer of aluminum over said passivating layer to a region remote from the aperture in the layer of passivating material, depositing on said aluminum layer a layer of silicon oxide and forming an aperture on the silicon oxide layer to expose a portion of the surface of the aluminum layer.
Claim 6
Dependent Claim
35 words
A method as claimed in claim 6 further including the step of removing the layer of silicon oxide over the portion of the aluminum layer extending through the aperture in the layer of passivating material.
Claim 7
Independent Claim
150 words
A method of forming on a face of a semiconductor body a contact for a semiconductor device within the semiconductor body, the method comprising providing a layer of passivating material on the contact-bearing face of the semiconductor body, exposing a region of the contact-bearing face of the semiconductor body where the contact is required, providing a layer of aluminum extending over the exposed region, depositing on the layer of aluminum at a selected region a layer of zinc from a solution of zinc oxide and a hydroxide of an alkali metal, removing the zinc layer at the selected region, depositing on the exposed region of the aluminum surface a zinc layer, said latter zinc layer initially having an activated surface, and depositing a layer of nickel on the activated surface of the zinc layer by the action of a suitable reducing agent on an acid solution of a nickel salt.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 8 in which the exposed nickel surface has been soldered with a tin-based solder and the nickel salt is nickel chloride.
Claim 9
Dependent Claim
26 words
A method as claimed in claim 8 in which the reducing agent for the nickel salt is selected from the group sodium hypophosphite and sodium borohydride.
Claim 10
Independent Claim
223 words
A method of forming on a face of a semiconductor body a contact for a semiconductor device within the semiconductor body, the method comprising providing a layer of passivating material on the contact-bearing face of the semiconductor body, forming an aperture in the layer of passivating material to expose a region of the semiconductor body where the contact is required, providing a layer of aluminum on the passivating material extending through the aperture in the layer of passivating material and over a region remote from the aperture, forming a masking layer of insulating material on said aluminum layer, removing a portion of said masking layer at the region remote from the aperture to expose a portion of the aluminum surface, depositing on at least a region of the exposed aluminum surface a first, temporary, layer of zinc from a solution of zinc oxide and a hydroxide of an alkali metal, removing the first zinc layer by etching with nitric acid solution, depositing on the reexposed region of the aluminum surface a second, permanent, zinc layer in the same manner as the first zinc layer, the second zinc layer initially having an activated surface, and depositing a layer of nickel on the activated surface of the zinc layer by the action of a suitable reducing agent on an acid solution of a nickel salt.
Claim 11
Dependent Claim
27 words
A method as claimed in claim 11 in which the exposed nickel surface has been soldered with a tin-based solder and the nickel salt is nickel chloride.
Claim 12
Dependent Claim
26 words
A method as claimed in claim 11 in which the reducing agent for the nickel salt is selected from the group sodium hypophosphite and sodium borohydride.
References Cited (Backward Citations)
US3212918A
Cited
US3579375A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |