Process for manufacturing a device comprising brazes produced from metal oxalate

• US 9,108,277 B2
• Filed: 06/29/2012
• Issued: 08/18/2015
• 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, Gougeon, Michel, Tailhades, Philippe, Raynaud, Lidwine, Baco, Valrie, Le Trong, Hoa
• Primary Examiner(s): Patel, Devang R
• Application Number:
  US13/539,239
• Publication Number:
  US 20130001275A1
• Time in Patent Office: 1,145 Days
• Field of Search: 228/121, 228/122.1, 228/203, 228/248.1
• US Class Current: 1/1
• 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 one support and at least one component, comprising:

precipitating a soluble metal salt by oxalic acid or ammonium oxalate to obtain a metal oxalate;

dissolving the metal oxalate in an aqueous-alcoholic solvent to obtain at least one of a suspension and a paste;

heating an assembly of the at least one support and the at least one component at a heating rate greater than around 150°

C./h; and

joining the at least one support and the at least one component by brazing with the at least one of a suspension and a paste, wherein the metal oxalate generates nanoscale metallic particles, wherein a melting temperature of the nanoscale metallic particles is lower than a melting temperature of the metal in a bulk state.

2. The process for manufacturing a device as claimed in claim 1,

wherein the aqueous-alcoholic solvent has a dielectric constant between 17 and 80, and

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 at least one surface of any of the at least one component and the at least one support comprises a film comprising gold or copper wherein the brazing is carried out on the surface.

4. The process for manufacturing a device as claimed in claim 1, wherein the at least one of a suspension and a paste comprises a suspension comprising the metal oxalate.

5. The process for manufacturing a device as claimed in claim 1, wherein the at least one of a suspension and a paste comprises a paste comprising the metal oxalate.

6. The process for manufacturing a device as claimed in claim 1, further comprising:

producing the at least one of a suspension and a paste comprising the metal oxalate;

depositing the at least one of a suspension and a paste on at least one surface of any of the at least one support and the at least one component;

assembling the at least one support and the at least one component via the at least one of a suspension and a paste to form a preconstituted assembly; and

heating the preconstituted assembly.

7. The process for manufacturing a device as claimed in claim 6, further comprising:

chemically precipitating, in an aqueous or aqueous-alcoholic medium, the soluble metal salt by oxalic acid or a soluble oxalate;

forming 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 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, further comprising:

spraying the at least one of a suspension and a paste on at least one surface of any of the at least one support and the at least one component.

9. The process for manufacturing a device as claimed in claim 1, further comprising:

depositing the at least one of a suspension and a paste on at least one surface of any of the at least one support and the at least one component by inkjet.

10. The process for manufacturing a device as claimed in claim 1, further comprising:

depositing the at least one of a suspension and a paste on at least one surface of any of the at least one support and the at least one component by coating.

11. The process for manufacturing a device as claimed in claim 1, further comprising:

depositing the at least one of a suspension and a paste on at least one surface of any of the at least one support and the at least one component by screen printing.

12. The process for manufacturing a device as claimed in claim 11, further comprising:

drying the deposit of the at least one of a suspension and a paste before assembling the at least one support and the at least one component.

13. The process for manufacturing a device as claimed in claim 12, further comprising:

carrying out the drying 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, further comprising:

heating an assembly of the at least one support and the at least one component at a temperature of around 200°

C.

15. The process for manufacturing a device as claimed in claim 1, wherein the at least one component is a power component comprising GaAs, GaN or SiC.