US5234153A
Expired / Lapsed
US
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Permanent metallic bonding method
Assignee: Agere Systems LLC
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Filing: 1992-08-28
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Granted: 1993-08-10
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Expires: 2012-08-28
Abstract
Abstract A laser device is bonded to a diamond submount by means of a procedure including (1) codepositing an auxiliary layer, on a layer of barrier metal that has been deposited overlying the submount, followed by (2) depositing a wetting layer on the auxiliary layer, and (3) by depositing a solder layer comprising alternating metallic layers, preferably of gold and tin sufficient to form an overall tin-rich gold-tin eutectic composition. The barrier metal is typically W, Mo, Cr, or Ru. Prior to bonding, a conventional metallization such as Ti-Pt-Au (three layers) is deposited on the laser device's bottom ohmic contact, typically comprising Ge. Then, during bonding, the solder layer is brought into physical contact with the laser device's metallization under enough heat and pressure, followed by cooling, to form a permanent joint between them. The thickness of the solder layer is advantageously less than approximately 5 μm. The wetting layer is preferably the intermetallic compound Ni 3 Sn 4 , and the auxiliary layer is formed by codepositing the metallic components of this intermetallic together with the barrier metal.
Inventors
- 👤 Donlad D. Bacon
- 👤 Avishay Katz
- 👤 Chien-Hsun Lee
- 👤 King L. Tai
- 👤 Yiu-Man Wong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:44
CPC Classifications
B; B23; B23K; B23K20/00; B23K20/02; B23K20/023; B23K20/22; B23K20/233; B23K35/00; B23K35/001; H; H01; H01S; H01S5/00; H01S5/02; H01S5/022; H01S5/02218; H10; H10W; H10W40/00; H10W40/20; H10W40/25; H10W40/254; B23K2035/008; H01S5/0235; H01S5/02355; H01S5/0237; H01S5/024; H01S5/02476; H01S5/02484; H10H; H10H20/00; H10H20/80; H10H20/83; H10H20/832; H10H20/85; H10H20/857; H10W72/00; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/07351; H10W72/07352; H10W72/30; H10W72/321; H10W72/351; H10W72/352; H10W72/50; H10W72/59
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
84 words
A process of bonding a first body to a second body, including the steps of: (a) forming, overlying at least a portion of a surface of the first body, a barrier layer composed of a barrier metal; (b) codepositing, overlying the barrier layer, an auxiliary layer composed of first and second metals together with the barrier metal; (c) forming, overlying the auxiliary layer, a wetting layer composed of the first and second metals; and (d) forming a layer of solder overlying the wetting layer.
Claim 2
Dependent Claim
84 words
A process of bonding a first body to a second body, including the steps of: (a) forming, overlying at least a portion of a surface of the first body, a barrier layer composed of a barrier metal; (b) codepositing, overlying the barrier layer, an auxiliary layer composed of first and second metals together with the barrier metal; (c) forming, overlying the auxiliary layer, a wetting layer composed of the first and second metals; and (d) forming a layer of solder overlying the wetting layer.
Claim 3
Dependent Claim
23 words
The process of claim 1 in which first and second metals form a stable intermetallic compound at least during the process of bonding.
Claim 4
Dependent Claim
17 words
The process of claim 1 in which the first and second metals respectively are nickel and tin.
Claim 5
Dependent Claim
24 words
The process of claim 3 in which the layer of solder is at least approximately a gold-tin eutectic or is a tin-rich gold-tin eutectic.
Claim 6
Dependent Claim
13 words
The process of claim 4 in which the barrier metal is essentially tungsten.
Claim 7
Dependent Claim
65 words
The process of claim 5 in which step (d) comprises: (1) depositing a first gold layer on the wetting layer; (2) depositing a first tin layer on the first gold layer; (3) depositing a second gold layer on the first tin layer; (4) depositing a second tin layer on the second gold layer; and (5) depositing a third gold layer on the second tin layer.
Claim 8
Dependent Claim
21 words
The process of claim 6 in which the overall thickness of the layer of solder is less than approximately 5 μm.
Claim 9
Dependent Claim
74 words
The process of claim 5 further including the step of heating the layer of solder above its melting temperature, and in which the wetting layer contains tin in an amount that is sufficient to prevent a change in the ratio of gold to tin contained in the layer of solder when heated above its melting temperature that would be so great as to change its melting temperature by more than approximately 20 C. degrees.
Claim 10
Dependent Claim
42 words
The process of claim 5 further comprising the steps of pressing the layer of solder against a metallic coating located on at least a portion of the surface of the second body, and heating the layer of solder above its melting temperature.
Claim 11
Dependent Claim
24 words
A process of bonding a first body to a second body in accordance with claim 3 in which the barrier metal is essentially tungsten.
Claim 12
Dependent Claim
15 words
The process of claim 10 in which the layer of solder comprises gold and tin.
Claim 13
Dependent Claim
19 words
The process of claim 11 in which thickness of the layer of solder is less than approximately 5 μm.
Claim 14
Dependent Claim
74 words
The process of claim 11 further including the step of heating the layer of solder above its melting temperature, and in which the wetting layer contains tin in an amount that is sufficient to prevent a change in the ratio of gold to tin contained in the layer of solder when heated above its melting temperature that would be so great as to change its melting temperature by more than approximately 20 C. degrees.
Claim 15
Dependent Claim
42 words
The process of claim 10 further comprising the steps of pressing the layer of solder against a metallic coating located on at least a portion of the surface of the second body, and heating the layer of solder above its melting temperature.
Claim 16
Dependent Claim
26 words
A process of bonding a first body to a second body in accordance with claim 3 in which the barrier metal is molybdenum, chromium, or ruthenium.
Claim 17
Dependent Claim
24 words
The process of claim 15 in which the layer of solder is at least approximately a gold-tin eutectic or is a tin-rich gold-tin eutectic.
Claim 18
Dependent Claim
64 words
The process of claim 16 in which step (d) comprises (1) depositing a first gold layer on the wetting layer; (2) depositing a first tin layer on the first gold layer; (3) depositing a second gold layer on the first tin layer; (4) depositing second tin layer on the second gold layer; and (5) depositing a third gold layer on the second tin layer.
Claim 19
Dependent Claim
74 words
The process of claim 17 further including the step of heating the layer of solder above its melting temperature, and in which the wetting layer contains tin in an amount that is sufficient to prevent a change in the ratio of gold to tin contained in the layer of solder when heated above its melting temperature that would be so great as to change its melting temperature by more than approximately 20 C. degrees.
Claim 20
Dependent Claim
74 words
The process of claim 16 further including the step of heating the layer of solder above its melting temperature, and in which the wetting layer contains tin in an amount that is sufficient to prevent a change in the ratio of gold to tin contained in the layer of solder when heated above its melting temperature that would be so great as to change its melting temperature by more than approximately 20 C. degrees.
Claim 21
Dependent Claim
42 words
The process of claim 1 further comprising the steps of pressing the layer of solder against a metallic coating located on at least a portion of the surface of the second body, and heating the layer of solder above its melting temperature.
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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) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |