Patent US4860939A successfully refreshed from Google Patents.
US4860939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for bonding a copper sheet to a substrate made of an electrically insulating material
Assignee: Telemecanique SA
•
Filing: 1988-11-10
•
Granted: 1989-08-29
•
Expires: 2008-11-10
Abstract
Abstract Disclosed is a method for the direct bonding of a copper sheet to a substrate made of an electrically insulating material, with the heating of the copper/substrate set in order to obtain a eutectic mixture. The method according to the invention consists in cleaning the copper to eliminate traces of oxidation on its surface before placing said copper on the substrate, in heating the copper/substrate set under a neutral atmosphere until a temperature greater than the temperature for the formation of the eutectic mixture is reached, and in applying the oxidating reactive gas only after the temperature greater than the temperature for the formation of the eutectic mixture is reached, in such a way that this temperature is reached before any oxidation of the surface of the copper.
Inventors
- 👤 Jannick Guinet
- 👤 Jean-Claude Hubert
- 👤 Marie-Francoise Martial
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:31
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/38; H10; H10W; H10W70/00; H10W70/01; H10W70/04; H10W70/047; H10W70/05; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0355
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
183 words
A method for the direct bonding of a copper sheet to a substrate made of electrically insulating material chosen from among alumina and aluminium nitride, said method consisting in the placing of a copper sheet on the substrate and in the heating of this set under a controlled atmosphere with the use, at least temporarily, of an oxidating reactive gas, at a temperature ranging between the temperature for the formation of a eutectic mixture, based on copper and the reactive gas, and the melting temperature of copper, and then in the cooling of the set, said method comprising the following steps: i--cleaning the copper to remove traces of oxidation at its surface before placing the copper on the substrate ii--heating the copper/substrate set under a neutral atmosphere until a temperature is obtained which is greater than the eutectic mixture forming temperature, and iii--applying the oxidating reactive gas only after the obtaining of a temperature greater than the temperature for the formation of the eutectic mixture in such a way that this temperature is reached before any oxidation of the surface of the copper.
Claim 2
Independent Claim
183 words
A method for the direct bonding of a copper sheet to a substrate made of electrically insulating material chosen from among alumina and aluminium nitride, said method consisting in the placing of a copper sheet on the substrate and in the heating of this set under a controlled atmosphere with the use, at least temporarily, of an oxidating reactive gas, at a temperature ranging between the temperature for the formation of a eutectic mixture, based on copper and the reactive gas, and the melting temperature of copper, and then in the cooling of the set, said method comprising the following steps: i--cleaning the copper to remove traces of oxidation at its surface before placing the copper on the substrate ii--heating the copper/substrate set under a neutral atmosphere until a temperature is obtained which is greater than the eutectic mixture forming temperature, and iii--applying the oxidating reactive gas only after the obtaining of a temperature greater than the temperature for the formation of the eutectic mixture in such a way that this temperature is reached before any oxidation of the surface of the copper.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein the copper sheet has a phosphorus content of less than 0.0015% by weight.
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein the copper sheet has an oxygen content of less than 0.0024% by weight.
Claim 5
Dependent Claim
21 words
A method according to claim 1, wherein the copper sheet has an oxygen content ranging between 0.0020% and 0.0024% by weight.
Claim 6
Dependent Claim
19 words
A method according to claim 1, wherein the substrate has a surface roughness of the order of 3.3±0.2 μm.
Claim 7
Dependent Claim
26 words
A method according to claim 1, wherein the substrate has a transition metal oxides content, notably an iron oxide content, of less than 0.08% by weight.
Claim 8
Dependent Claim
21 words
A method according to claim 1, wherein the copper/substrate set is heated up to a temperature of 1075° C. ±2° C.
Claim 9
Dependent Claim
29 words
A method according to claim 1, wherein the copper/substrate set is heated at a steady level of temperature of 1075°±2° C. for a period of 2 to 4 min.
Claim 10
Dependent Claim
41 words
A method according to claim 1, wherein the reactive gas applied after the obtaining of a temperature greater than the temperature of the eutectic mixture is formed by oxygen at a partial pressure of 50 to 100 ppm, preferably 70 ppm.
Claim 11
Dependent Claim
16 words
A method according to claim 1, wherein the cooling stage is done under a neutral atmosphere.
Claim 12
Dependent Claim
14 words
A method according to claim 1, wherein the neutral atmosphere is formed by nitrogen.
Claim 13
Dependent Claim
36 words
A method according to claim 1, wherein the copper cleaning step consists in the cleaning of said copper in a diluted solution of hydrochloric acid and then in the rinsing of the copper in de-ionized water.
References Cited (Backward Citations)
CH202198A
Cited
GB584931A
Cited
US2517248A
Cited
GB761045A
Cited
US3517432A
Cited
US4050956A
Cited
FR2181049A1
Cited
US3911553A
Cited
US3994430A
Cited
DE3036128A1
Cited
US4505418A
Cited
DE3204167A1
Cited
EP0097944A2
Cited
US4693409A
Cited
EP0123212A2
Cited
DE3324661A1
Cited
US4591401A
Cited
US4563383A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |