Patent US4017495A successfully refreshed from Google Patents.
US4017495A
Expired / Lapsed
US
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Encapsulation of integrated circuits
Assignee: AT&T Inc
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Filing: 1975-10-23
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Granted: 1977-04-12
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Expires: 1995-10-23
Abstract
Abstract Disclosed is a method of encapsulating integrated circuit chips formed on an insulating substrate which permits complete filling of areas under the chip. The encapsulant employed is a dispersion of a material, such as a silicone elastomer, which cures by reaction with water vapor. Subsequent to application of the encapsulant over and under the chip, the solvent of the dispersion is evaporated during a pre-cure treatment by means of a dry ambient of less than 5% relative humidity which suppresses crosslinking. After essentially all the solvent is thus removed, the encapsulant is cured by exposure to a second ambient of higher relative humidity which enhances crosslinking.
Inventors
- 👤 Donald Jaffe
- 👤 Nicholas Alec Soos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:06
CPC Classifications
H; H10; H10W; H10W74/00; H10W74/01; H10W74/10; H10W74/111; H10W74/114; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49146
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
99 words
A method of encapsulating a circuit element formed on an insulating substrate wherein a gap exists between the element and the substrate and whereby the area under the element is filled with encapsulant comprising the steps of: applying over and under said element an encapsulant comprising a dispersion of a material which cures by reaction with moisture; evaporating the solvent of said dispersion by exposure to a first dry ambient with a relative humidity of less than 5%, which suppresses crosslinking and curing the material by exposure to a second ambient with a relative humidity of at least 20%.
Claim 2
Independent Claim
99 words
A method of encapsulating a circuit element formed on an insulating substrate wherein a gap exists between the element and the substrate and whereby the area under the element is filled with encapsulant comprising the steps of: applying over and under said element an encapsulant comprising a dispersion of a material which cures by reaction with moisture; evaporating the solvent of said dispersion by exposure to a first dry ambient with a relative humidity of less than 5%, which suppresses crosslinking and curing the material by exposure to a second ambient with a relative humidity of at least 20%.
Claim 3
Dependent Claim
35 words
The method according to claim 1 wherein the circuit element is a beam-leaded integrated circuit chip which is raised above the surface of said substrate so as to form a gap between chip and substrate.
Claim 4
Dependent Claim
14 words
The method according to claim 1 wherein the solvent of said dispersion comprises xylene.
Claim 5
Dependent Claim
14 words
The method according to claim 1 wherein the encapsulating material comprises a silicone elastomer.
Claim 6
Dependent Claim
12 words
The method according to claim 1 wherein the first ambient comprises nitrogen.
Claim 7
Dependent Claim
12 words
The method according to claim 1 wherein the second ambient comprises air.
Claim 8
Dependent Claim
19 words
The method according to claim 1 wherein the solvent is evaporated for a time of at least one hour.
Claim 9
Dependent Claim
18 words
The method according to claim 1 wherein the relative humidity of the first ambient is less than 1%.
Claim 10
Dependent Claim
19 words
The method according to claim 1 wherein the relative humidity of the second ambient is within the range 20-60%.
Claim 11
Independent Claim
113 words
A method of encapsulating a beam-leaded integrated circuit chip formed on an insulating substrate wherein a gap exists between the chip and the substrate and whereby the area under the chip is filled with encapsulant comprising the steps of: applying over and under said chip and substrate an encapsulant comprising a dispersion of a room temperature vulcanizing silicone elastomer which cures by reaction with moisture; evaporating the solvent of said dispersion by exposure to a first dry ambient with a relative humidity of less than 5% for a minimum of 1 hour, which suppresses crosslinking; and curing the material by exposure to a second ambient with a relative humidity in the range 20-60%.
Claim 12
Independent Claim
113 words
A method of encapsulating a beam-leaded integrated circuit chip formed on an insulating substrate wherein a gap exists between the chip and the substrate and whereby the area under the chip is filled with encapsulant comprising the steps of: applying over and under said chip and substrate an encapsulant comprising a dispersion of a room temperature vulcanizing silicone elastomer which cures by reaction with moisture; evaporating the solvent of said dispersion by exposure to a first dry ambient with a relative humidity of less than 5% for a minimum of 1 hour, which suppresses crosslinking; and curing the material by exposure to a second ambient with a relative humidity in the range 20-60%.
Claim 13
Independent Claim
130 words
A method of encapsulating a beam-leaded integrated circuit chip with sides at least 0.080 inches long formed on an insulating substrate wherein a gap exists between chip and substrate in the range of 0.01 - 0.003 inches and whereby the area under the chip is filled with encapsulant comprising the steps of: applying over and under said chip and substrate an encapsulant comprising a dispersion of a solvent comprising zylene and a room temperature vulcanizing silicone elastomer which cures by reaction with moisture; evaporating essentially all of the solvent by exposure to a first ambient comprising nitrogen with a relative humidity of less than 1% for a minimum of three hours which suppresses crosslinking; and curing the material by exposure to air with a relative humidity in the range 20-60%.
Claim 14
Independent Claim
130 words
A method of encapsulating a beam-leaded integrated circuit chip with sides at least 0.080 inches long formed on an insulating substrate wherein a gap exists between chip and substrate in the range of 0.01 - 0.003 inches and whereby the area under the chip is filled with encapsulant comprising the steps of: applying over and under said chip and substrate an encapsulant comprising a dispersion of a solvent comprising zylene and a room temperature vulcanizing silicone elastomer which cures by reaction with moisture; evaporating essentially all of the solvent by exposure to a first ambient comprising nitrogen with a relative humidity of less than 1% for a minimum of three hours which suppresses crosslinking; and curing the material by exposure to air with a relative humidity in the range 20-60%.
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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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |