US5106009A
Expired / Lapsed
US
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Methods of joining components
Assignee: Dynex Semiconductor Ltd
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Filing: 1990-09-04
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Granted: 1992-04-21
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Expires: 2010-09-04
Abstract
Abstract A method of joining components by soldering comprising forming discrete layers of silver (13, 17) and another metal (19), e.g. a tin or indium based material, the two layers having volumes in a ratio different from that in the eutectic alloy formed by silver and that metal, and raising the temperature of the layers above the melting point of the eutectic alloy for a period sufficient to cause initially formation of the eutectic alloy and then, by reaction between the eutectic alloy and one or other of silver and the other metal, formation of a material having a melting point higher than the eutectic alloy melting point. The method allows soldering, e.g. of a silicon wafer (1) to a header (3), at a relatively low temperature below that which the joint will withstand after formation.
Inventors
- 👤 Giles Humpston
- 👤 David M. Jacobson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:16
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/30; B23K35/3006; H; H10; H10W; H10W70/00; H10W70/20; H10W70/24; H10W72/00; H10W72/30; B23K35/001; B23K2035/008; B23K35/005; B23K35/007; B23K35/26; B23K35/262; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/321; H10W72/322; H10W72/351; H10W72/352; H10W72/50; H10W72/59
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
140 words
A method of joining components comprising the steps of: providing between the components discrete layers, each in the form of a coating applied to a respective said component or a said layer carried thereby, and each consisting either substantially of silver or substantially of another metal, there being at least one layer of each metal, the silver and another metal in said layers having total volumes in a ratio different from that in a eutectic alloy formed by silver and said another metal; and raising the temperature of said layers above the melting point of said eutectic alloy for a period sufficient to cause initially formation of said eutectic alloy and then, by reaction between said eutectic alloy and one or other of silver and said another metal, formation of a material having a melting point higher than said temperature.
Claim 2
Independent Claim
140 words
A method of joining components comprising the steps of: providing between the components discrete layers, each in the form of a coating applied to a respective said component or a said layer carried thereby, and each consisting either substantially of silver or substantially of another metal, there being at least one layer of each metal, the silver and another metal in said layers having total volumes in a ratio different from that in a eutectic alloy formed by silver and said another metal; and raising the temperature of said layers above the melting point of said eutectic alloy for a period sufficient to cause initially formation of said eutectic alloy and then, by reaction between said eutectic alloy and one or other of silver and said another metal, formation of a material having a melting point higher than said temperature.
Claim 3
Dependent Claim
27 words
A method according to claim 1 wherein the volume fraction of silver in said layers is greater than the volume fraction of silver in said eutectic alloy.
Claim 4
Dependent Claim
17 words
A method according to claim 1 wherein said another metal is tin or a tin based material.
Claim 5
Dependent Claim
13 words
A method according to claim 3 wherein said temperature is substantially 275° C.
Claim 6
Dependent Claim
27 words
A method according to claim 3 wherein the volume of silver in said layers is substantially 70% of the total volume of all said discrete layers together.
Claim 7
Dependent Claim
17 words
A method according to claim 1 wherein said another metal is indium or an indium based material.
Claim 8
Dependent Claim
13 words
A method according to claim 6 wherein said temperature is substantially 175° C.
Claim 9
Dependent Claim
27 words
A method according to claim 6 wherein the volume of silver in said layers is substantially 77% of the total volume of all said discrete layers together.
Claim 10
Dependent Claim
15 words
A method according to claim 1 wherein said period is between one and two hours.
Claim 11
Dependent Claim
18 words
A method according to claim 1 wherein both said components carry a said layer consisting substantially of silver.
Claim 12
Dependent Claim
22 words
A method according to claim 10 wherein a said layer of said another metal is carried on one only of said components.
Claim 13
Dependent Claim
15 words
A method according to claim 1 wherein one of said components consists substantially of silicon.
Claim 14
Dependent Claim
29 words
A method according to claim 12 wherein the surface of the silicon component to be joined is provided with a sintered aluminum layer overlaid by titanium and platinum layers.
Claim 15
Dependent Claim
18 words
A method according to claim 12 wherein the other of said components consists substantially of molybdenum or tungsten.
Claim 16
Dependent Claim
18 words
A method according to claim 12 wherein the other of said components consists substantially of an iron-nickel alloy.
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) | 1995-04-21 | 1995-10-21 | 1996-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-21 | 1999-10-21 | 2000-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-21 | 2003-10-21 | 2004-04-21 | $7700.00 | Window Closed / Lapsed |