US4059708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for selective encapsulation
Assignee: AT&T Inc
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Filing: 1976-07-30
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Granted: 1977-11-22
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Expires: 1996-07-30
Abstract
Abstract Disclosed is a method for encapsulating selected areas of solid state integrated circuits. The areas which are to remain uncoated are covered with a water and/or alcohol soluble polymer of sufficient viscosity to form stable droplets. The encapsulant is then applied, usually by flow coating, and cured. The polymer mask is removed by applying a material such as water or alcohol which does not affect the encapsulant. The method thus allows relatively small areas to be masked without any significant residue left on the circuit.
Inventors
- 👤 John Herbert Heiss, Jr.
- 👤 Joel Mark Schoen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:17
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/61; H10W; H10W74/00; H10W74/01; H10W74/10; H10W74/131; H10W74/40; H10W74/47; H10W74/476
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
138 words
A method of selectively encapsulating a solid state integrated circuit formed on an insulating board comprising the steps of: depositing on a selected area of the circuit a mask in the form of a stable droplet in a dome configuration with a height within the range 30-50 mils, said mask comprising a water soluble polymer which is inert to the organic solvents included in the encapsulant; applying an encapsulating material comprising a room temperature vulcanizing silicone rubber dissolved in an organic solvent to said circuit by flow coating the material over the area of the circuit not covered by said mask; curing said encapsulating material; and dissolving said polymer material by applying water thereto so as to expose the area of the circuit covered by said polymer and leave encapsulating material on the remaining area of the circuit.
Claim 2
Independent Claim
138 words
A method of selectively encapsulating a solid state integrated circuit formed on an insulating board comprising the steps of: depositing on a selected area of the circuit a mask in the form of a stable droplet in a dome configuration with a height within the range 30-50 mils, said mask comprising a water soluble polymer which is inert to the organic solvents included in the encapsulant; applying an encapsulating material comprising a room temperature vulcanizing silicone rubber dissolved in an organic solvent to said circuit by flow coating the material over the area of the circuit not covered by said mask; curing said encapsulating material; and dissolving said polymer material by applying water thereto so as to expose the area of the circuit covered by said polymer and leave encapsulating material on the remaining area of the circuit.
Claim 3
Dependent Claim
31 words
The method according to claim 1 wherein the polymer material is selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, polyethylene oxide, polyacrylic acid, carboxy methyl cellulose, and gelatin.
Claim 4
Dependent Claim
24 words
The method according to claim 1 wherein the encapsulating material comprises a dimethyl siloxane long chain polymer with methoxy end groups dissovled in xylene.
Claim 5
Dependent Claim
20 words
The method according to claim 1 wherein the polymer material comprises mannitol-mannite and potato dextrin dissolved in a glycerin base.
Claim 6
Dependent Claim
51 words
The method according to claim 1 wherein the encapsulating material is cured by keeping the circuit at room temperature and at a relative humidity between 30 and 60% followed by heating the circuit at a temperature in the range 90°-140° C for a period of time in the range 2-6 hours.
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) | 1980-11-21 | 1981-05-23 | 1981-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-21 | 1985-05-23 | 1985-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-21 | 1989-05-23 | 1989-11-22 | $7700.00 | Window Closed / Lapsed |