Process for Manufacturing a Device Comprising Brazes Produced from Metal Oxalate

• US 20130001275A1
• Filed: 06/29/2012
• Published: 01/03/2013
• Est. Priority Date: 06/30/2011
• Status: Active Grant

• Current Assignee: Centre National De La Recherche Scientifique, Thales SA, Universite Paul Sabatier Toulouse Iii
• Original Assignee: Centre National De La Recherche Scientifique, Thales SA, Universite Paul Sabatier Toulouse Iii
• Inventors: VENDIER, Olivier, RAYNAUD, Lidwine, BACO, Valérie, GOUGEON, Michel, LE TRONG, Hoa, TAILHADES, Philippe
• Granted Patent: US 9,108,277 B2
• Time in Patent Office: Days
• US Class Current: 228/121
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 35/02 characterised by mechanical features, e.g. shape
• CPC Class Codes: B23K 35/025 Pastes, creams, slurries
• CPC Class Codes: B23K 35/30 with the principal constituent melting at less than 1550 degrees C
• CPC Class Codes: B23K 35/3006 Ag as the principal constituent
• CPC Class Codes: B23K 35/36 Selection of non-metallic compositions, e.g. coatings, fluxes B23K35/34 takes precedence; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest selection of soldering or welding materials proper B23K35/24
• CPC Class Codes: B23K 35/3616 Halogen compounds
• CPC Class Codes: B23K 35/3618 Carboxylic acids or salts
• CPC Class Codes: H01L 2224/29339 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/29347 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/83191 wherein the layer connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83193 wherein the layer connectors are disposed on both the semiconductor or solid-state body and another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 2224/8384 Sintering
• CPC Class Codes: H01L 24/27 Manufacturing methods
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0105 Tin [Sn]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/013 : Alloys
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/10272 : Silicon Carbide [SiC]
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/1033 : Gallium nitride [GaN]
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent

Abstract

A process for manufacturing a device comprising at least a support and a component, joined together by at least one braze, includes a brazing operation which is carried out starting from a metal oxalate. Advantageously, it is a silver oxalate or a mixture of silver and copper oxalates, the component and/or the support being covered with a film comprising gold or copper in contact with said braze and the component possibly being a power component.

Claims

1. A process for manufacturing a device comprising at least a support and a component, joined together by at least one braze wherein the brazing operation is carried out starting from a metal oxalate, the metal oxalate being obtained by the chemical precipitation of a soluble metal salt, by oxalic acid or ammonium oxalate, dissolved in aqueous-alcoholic solvents preferably having dielectric constants between 17 and 80.

2. The process for manufacturing a device as claimed in claim 1, wherein the oxalate is a silver oxalate or a mixture of silver and copper oxalates.

3. The process for manufacturing a device as claimed in claim 1, wherein the component and/or the support comprise, at the surface, a film comprising gold or copper on which said braze is produced.

4. The process for manufacturing a device as claimed in claim 1, wherein the braze is produced from a suspension containing metal oxalate.

5. The process for manufacturing a device as claimed in claim 1, wherein the braze is produced from a paste containing metal oxalate.

6. The process for manufacturing a device as claimed in claim 1, wherein the brazing operation further comprises:

production of a suspension or of a paste, to be brazed containing metal oxalate;

deposition of said suspension or of said paste on the surface of said support and/or of said component;

assembling of the support and of the component via said suspension or said paste;

heating of the preconstituted assembly.

7. The process for manufacturing a device as claimed in claim 6, wherein the production of said suspension or of said paste further comprises:

chemical precipitation, in an aqueous or aqueous-alcoholic medium, of a soluble metal salt by oxalic acid or a soluble oxalate;

obtaining an oxalate precipitate having controlled particle size and morphological characteristics resulting in particle sizes of greater than 40 nm for the oxalate comprising copper and around 0.1 micron for the silver oxalate;

washing of the precipitate formed;

putting the oxalate into suspension in an aqueous or aqueous-alcoholic medium at a chosen concentration in order to obtain a suspension or a paste of controlled viscosity.

8. The process for manufacturing a device as claimed in claim 1, wherein the oxalate-based suspension is deposited by spraying.

9. The process for manufacturing a device as claimed in claim 1, wherein the oxalate-based suspension is deposited by inkjet.

10. The process for manufacturing a device as claimed in claim 1, wherein the oxalate-based paste is deposited by coating.

11. The process for manufacturing a device as claimed in claim 1, wherein the oxalate-based paste is deposited by screen printing.

12. The process for manufacturing a device as claimed in claim 1, further comprising drying the deposit of said suspension or of said paste before the assembling of the support and component, via said suspension or said paste based on metal oxalate.

13. The process for manufacturing a device as claimed in claim 12, wherein the drying is carried out at a temperature of around 100°

C. in air or under primary vacuum.

14. The process for manufacturing a device as claimed in claim 1, wherein the heating of the assembly is carried out at a temperature of around 200°

C.

15. The process for manufacturing a device as claimed in claim 1, wherein the heating of the assembly is carried out at a heating rate greater than around 150°

C./h.

16. The process for manufacturing a device as claimed in claim 1, wherein the component is a power component, which may be based on GaAs, GaN or SiC.