US4895291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a hermetic seal in a solid-state device
Assignee: Eastman Kodak Co
•
Filing: 1989-05-04
•
Granted: 1990-01-23
•
Expires: 2009-05-04
Abstract
Abstract A method of making a hermetic seal for a solid-state device is disclosed. The device includes a ceramic housing having a cavity for an element such as an image sensor. A cover formed of a transparent material is sealed to the housing to close the cavity. A metallization support is formed on the cover and on the housing. In order to form a hermetic seal at a relative low temperature, a layer of indium is coated on the metallization support of either the cover or the housing, and a layer of tin is coated on the support of the other of the two parts. The cover is then placed on the housing, and the parts are placed in a furnace where a temperature under the melting temperature of the composite alloy of tin and indium is maintained for a period long enough to diffuse the tin and indium together. The temperature is then raised to a temperature sufficient to melt the alloy, and the device is then slowly cooled to ambient temperature.
Inventors
- 👤 Edward J. Ozimek
- 👤 Edward Carnall, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:12
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/19; B23K35/00; B23K35/001; H; H10; H10W; H10W76/00; H10W76/60; H10W95/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
137 words
A method of making a hermetic seal in a solid-state device, said method comprising the steps of: forming a metallization support on a housing; forming a metallization support on a cover for said housing; forming a layer of indium on one of said supports; forming a layer of tin on the other of said supports; positioning said cover and said housing such that said layers of indium and tin are in contact with each other; heating said cover and housing to a temperature of between about 70% and about 90% of the melting temperature of a composite alloy of tin and indium to diffuse said tin and indium together; heating said cover and housing to a temperature sufficient to melt said alloy after said diffusion is complete; and slowly cooling the cover and housing to ambient temperature.
Claim 2
Independent Claim
137 words
A method of making a hermetic seal in a solid-state device, said method comprising the steps of: forming a metallization support on a housing; forming a metallization support on a cover for said housing; forming a layer of indium on one of said supports; forming a layer of tin on the other of said supports; positioning said cover and said housing such that said layers of indium and tin are in contact with each other; heating said cover and housing to a temperature of between about 70% and about 90% of the melting temperature of a composite alloy of tin and indium to diffuse said tin and indium together; heating said cover and housing to a temperature sufficient to melt said alloy after said diffusion is complete; and slowly cooling the cover and housing to ambient temperature.
Claim 3
Dependent Claim
23 words
A method, as defined in claim 1, wherein each of said supports includes a layer of nickel and a layer of gold thereon.
Claim 4
Dependent Claim
28 words
A method, as defined in claim 1, wherein said metallization supports are cleaned using a plasma etch prior to being coated with a layer of indium or tin.
Claim 5
Dependent Claim
19 words
A method, as defined in claim 1, wherein said melting temperature of the composite alloy is about 125° C.
Claim 6
Dependent Claim
27 words
A method, as defined in claim 5, wherein said cover and housing are heated to a temperature of 100° C. to diffuse said tin and indium together.
Claim 7
Dependent Claim
16 words
A method, as defined in claim 1, wherein said housing is formed of a ceramic material.
Claim 8
Dependent Claim
12 words
A method, as defined in claim 1, wherein said cover is transparent.
Claim 9
Dependent Claim
41 words
A method, as defined in claim 1, wherein alternating layers of indium and tin are formed on each of said supports, and a top layer on said one support is indium and a top layer on said other support is tin.
Claim 10
Independent Claim
179 words
A method of making a hermetic seal in a solid-state device, said method comprising: forming a metallization support on a housing, said support having a base layer of tungsten and a gold layer deposited on the tungsten layer; forming a metallization support on a cover for said housing, said support having a base layer of a titanium-tungsten alloy and a gold layer deposited on the alloy; forming alternating layers of indium and tin on one of said supports, the top layer on said one support being indium; forming alternating layers of tin and indium on the other of said supports, the top layer on said other support being tin; positioning said cover and said housing such that said top layers of indium and tin are in contact with each other; heating said cover and housing to a temperature of about 100° C. for about four hours to diffuse said tin and indium together; heating said cover and housing to a temperature of about 130° C. for about 10 minutes; and slowly cooling the cover and housing to ambient temperature.
Claim 11
Independent Claim
179 words
A method of making a hermetic seal in a solid-state device, said method comprising: forming a metallization support on a housing, said support having a base layer of tungsten and a gold layer deposited on the tungsten layer; forming a metallization support on a cover for said housing, said support having a base layer of a titanium-tungsten alloy and a gold layer deposited on the alloy; forming alternating layers of indium and tin on one of said supports, the top layer on said one support being indium; forming alternating layers of tin and indium on the other of said supports, the top layer on said other support being tin; positioning said cover and said housing such that said top layers of indium and tin are in contact with each other; heating said cover and housing to a temperature of about 100° C. for about four hours to diffuse said tin and indium together; heating said cover and housing to a temperature of about 130° C. for about 10 minutes; and slowly cooling the cover and housing to ambient temperature.
References Cited (Backward Citations)
US3590467A
Cited
US3857161A
Cited
US3909917A
Cited
US4020987A
Cited
US4077558A
Cited
US4159075A
Cited
US4293986A
Cited
US4599538A
Cited
US4610934A
Cited
US4836434A
Cited
US4750665A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-22 | 1993-07-24 | 1994-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-22 | 1997-07-24 | 1998-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-22 | 2001-07-24 | 2002-01-23 | $7700.00 | Window Closed / Lapsed |