Patent US4622433A successfully refreshed from Google Patents.
US4622433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic package system using low temperature sealing glasses
Assignee: Diacon Inc
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Filing: 1984-03-30
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Granted: 1986-11-11
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Expires: 2004-03-30
Abstract
Abstract In accordance with the preferred embodiments of the invention, provided is a hermetic ceramic/glass enclosure for encapsulating semiconductor components which reduces the internal cavity moisture and contamination levels, has a stronger package seal and a lower sealing temperature than hermetic ceramic/glass enclosures currently used. Included in the first embodiment is a lower substrate, with a conductive leadframe attached thereto via devitrified glass and a layer of vitreous glass on the leadframe for attaching a cap which also includes a layer of vitreous glass. To seal the enclosure, the cap is heated to a temperature T1 above the melting point of the vitreous glass, and the lower substrate, is maintained at a temperature high enough to bond to the vitreous layer on the cap on contact, but low enough to eliminate damage to the semiconductor component and additional Gold-Silicon eutectic formation between the semiconductor component and the enclosure lower substrate. In a second embodiment, the cap includes heat treated vitreous glass that reduces contamination outgassing during the final enclosure seal process and a gettering pad disposed on the interior surface of the cap for gettering residual moisture from the internal cavity of the enclosure. A third embodiment is also provided which is especially adapted for high pin-count packages, and includes a windowframe on the top of and attached to the leadframe by devitrified glass. The windowframe has a layer of vitreous glass to facilitate final enclosure seal and a reduction in the seal area required.
Inventors
- 👤 Thomas J. Frampton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:55
CPC Classifications
H; H10; H10W; H10W76/00; H10W76/40; H10W76/42; H10W76/48; H10W76/60; H10W95/00; H10W70/00; H10W70/60; H10W70/67; H10W70/68; H10W70/682; H10W72/00; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W90/00; H10W90/701; H10W90/751; H10W90/756; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49146
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
91 words
An enclosure for encapsulating an electronic component comprising: a substrate having a perimeter; a composite layer over said substrate, said layer having a first glass portion which is devitrified and is located over at least a part of said substrate and a second glass portion which is vitreous and is located above said first glass portion; a conductive lead frame attached to said substrate and imbedded in said composite layer on said substrate, said lead frame having surfaces exposed for electrical contact both within and without the perimeter of said substrate.
Claim 2
Dependent Claim
91 words
An enclosure for encapsulating an electronic component comprising: a substrate having a perimeter; a composite layer over said substrate, said layer having a first glass portion which is devitrified and is located over at least a part of said substrate and a second glass portion which is vitreous and is located above said first glass portion; a conductive lead frame attached to said substrate and imbedded in said composite layer on said substrate, said lead frame having surfaces exposed for electrical contact both within and without the perimeter of said substrate.
Claim 3
Dependent Claim
31 words
An enclosure as in claim 1 wherein said composite layer further comprises a third glass portion which is substantially devitrified adjacent said conductive lead frame, with said second glass portion thereabove.
Claim 4
Dependent Claim
25 words
An enclosure as in claim 2 wherein said composite layer further comprises a windowframe disposed between said second glass portion and said third glass portion.
Claim 5
Dependent Claim
36 words
An enclosure as in claim 3 further comprising: a semiconductor device attached to said substrate and electrically connected to said lead frame; and a cap covering said semiconductor device and sealed to said second glass portion.
Claim 6
Dependent Claim
33 words
An enclosure as in claim 4 further comprising a layer of vitreous glass attached to said cap which forms part of the seal together with said second glass portion of said composite layer.
Claim 7
Dependent Claim
22 words
An enclosure as in claim 5 wherein said cap further comprises gettering means for removing moisture from the inside of said enclosure.
Claim 8
Dependent Claim
26 words
An enclosure as in claim 5 wherein said gettering means comprises a pad of aluminum on said cap and disposed in the interior of said enclosure.
Claim 9
Dependent Claim
22 words
An enclosure as in claim 4 wherein said cap further comprises gettering means for removing moisture from the inside of said enclosure.
Claim 10
Dependent Claim
26 words
An enclosure as in claim 8 wherein said gettering means comprises a pad of aluminum on said cap and disposed in the interior of said enclosure.
Claim 11
Dependent Claim
36 words
An enclosure as in claim 1 further comprising: a semiconductor device attached to said substrate and electrically connected to said lead frame; and a cap covering said semiconductor device and sealed to said second glass portion.
Claim 12
Dependent Claim
32 words
An enclosure as in claim 10 further comprising a layer of vitreous glass attached to said cap which forms part of the seal together with said second portion of said composite layer.
Claim 13
Dependent Claim
23 words
An enclosure as in claim 11 wherein said cap further comprises metallic gettering means for removing moisture from the inside of said enclosure.
Claim 14
Dependent Claim
27 words
An enclosure as in claim 12 wherein said metallic gettering means comprises a pad of aluminum on said cap and disposed in the interior of said enclosure.
Claim 15
Dependent Claim
23 words
An enclosure as in claim 10 wherein said cap further comprises metallic gettering means for removing moisture from the inside of said enclosure.
Claim 16
Dependent Claim
26 words
An enclosure as in claim 14 wherein said gettering means comprises a pad of aluminum on said cap and disposed in the interior of said enclosure.
Claim 17
Independent Claim
173 words
A method of sealing an enclosure for a semiconductor component, said enclosure having an upper portion with a gettering pad thereon which is disposed in an interior of the enclosure when the enclosure is sealed, said upper portion having a layer of vitreous glass thereon, and said enclosure having a lower portion holding said semiconductor component in a fixed position with said lower portion having a layer of vitreous glass thereon for affecting a hermetic seal with said upper portion, the steps comprising: a. heating said upper portion to a first temperature T1 greater than the melting point of said vitreous glass; b. heating said lower portion to a second temperature T2 which is high enough to form a bond on contact with said upper portion at temperature T1, said temperture T2 being below the gold-silicon eutectic temperature and below the temperature T1; c. placing said upper portion in contact with said lower portion to form a seal, after heating said upper portion to temperature T1 and said lower portion to temperature T2.
Claim 18
Independent Claim
173 words
A method of sealing an enclosure for a semiconductor component, said enclosure having an upper portion with a gettering pad thereon which is disposed in an interior of the enclosure when the enclosure is sealed, said upper portion having a layer of vitreous glass thereon, and said enclosure having a lower portion holding said semiconductor component in a fixed position with said lower portion having a layer of vitreous glass thereon for affecting a hermetic seal with said upper portion, the steps comprising: a. heating said upper portion to a first temperature T1 greater than the melting point of said vitreous glass; b. heating said lower portion to a second temperature T2 which is high enough to form a bond on contact with said upper portion at temperature T1, said temperture T2 being below the gold-silicon eutectic temperature and below the temperature T1; c. placing said upper portion in contact with said lower portion to form a seal, after heating said upper portion to temperature T1 and said lower portion to temperature T2.
Claim 19
Dependent Claim
28 words
A method as in claim 16 further comprising: d. baking said sealed enclosure at a temperature T3 which is greater than 100° C., but less than 200° C.
Claim 20
Dependent Claim
15 words
A method as in claim 17 wherein said temperature T3 is less than 175° C.
Claim 21
Dependent Claim
41 words
A method as in claim 16 further comprising the step of heating said upper portion to a temperature T4 which is higher than temperature T1 to cause outgassing from said upper portion before heating said upper portion to said temperature T1.
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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) | 1989-11-10 | 1990-05-12 | 1990-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-10 | 1994-05-12 | 1994-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-10 | 1998-05-12 | 1998-11-11 | $7700.00 | Window Closed / Lapsed |