Method for interconnecting components of an electronic system by sintering

Patent metadata

Field	Value
Publication number	US-11919083-B2
Application number	US-202117446770-A
Country	US
Kind code	B2
Filing date	Sep 2, 2021
Priority date	Sep 3, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A method for interconnecting components of an electronic system includes depositing a sintering solution onto a first component to form an interconnection layer, the sintering solution having metal nanoparticles dispersed in a solvent, and a stabilizing agent adsorbed onto the nanoparticles. The nanoparticles have for more than 95.0% of their mass a metal selected from silver, gold, copper and alloys thereof and have a polyhedral shape with an aspect ratio of more than 0.8. The method also includes eliminating, at least partially, solvent from the layer to form an agglomerate in which the stabilizing agent binds nanoparticles together and maintains at least a portion of the nanoparticles at a distance from each other; debinding and sintering the layer by bringing the agglomerate into contact with a destabilizing agent to aggregate and coalesce the nanoparticles and depositing a second component in contact with the layer before or during debinding or sintering.

First claim

The invention claimed is:

1. A method for interconnecting components of an electronic system, the method comprising the steps of:
a) depositing a sintering solution onto a first component in order to form an interconnection layer, the sintering solution consisting off a solvent, metal nanoparticles dispersed in the solvent, a stabilizing agent adsorbed onto the metal nanoparticles and keeping the metal nanoparticles apart,
the metal nanoparticles comprising for more than 95.0% of their mass a metal selected from silver, gold, copper and alloys thereof and having a polyhedral shape with an aspect ratio of more than 0.8,
b) eliminating, at least partially, the solvent from the interconnection layer such as to form at least one agglomerate in which the stabilizing agent binds them together and maintains at least a portion of the metal nanoparticles at a distance from each other,
c) debinding and sintering the interconnection layer, at a temperature of less than 200° C., by bringing the agglomerate into contact with at least one destabilizing agent configured to desorb the stabilizing agent from the metal nanoparticles in order to aggregate and coalesce said metal nanoparticles between themselves, and
d) depositing a second component in contact with the interconnection layer before or during debinding or sintering.

2. The method according to claim 1 , the metal nanoparticles comprising for more than 99.0% of their mass a metal selected from silver, gold, copper and alloys thereof.

3. The method according to claim 1 , the solvent being such that its thermal degradation results in the formation of the destabilizing agent.

4. The method according to claim 1 , more than 99.0% of the mass of the metal nanoparticles being constituted by silver.

5. The method according to claim 1 , the metal nanoparticles being cubic in shape, optionally truncated.

6. The method according to claim 1 , the sintering solution comprising, as percentages by weight expressed on the basis of the mass of the sintering solution:
between 20.0% and 90.0% of polyhedral metal nanoparticles,
between 0.1% and 3.0% of stabilizing agent, and
between 7.0% and 79.9% of solvent.

7. The method according to claim 1 , the sintering solution comprising a particulate assembly formed from metal microparticles, the smallest microparticles having a size of more than 1 μm, the sintering solution comprising, as percentages by weight expressed on the basis of the mass of the sintering solution:
between 0.1% and 3.0% of stabilizing agent,
between 7.0% and 79.9% of solvent, and
between 20.0% and 90.0% of metal nanoparticles and of metal microparticles,
a ratio of the metal microparticles content to a sum of the metal nanoparticles content and metal microparticles content being in a range 0.3 to 0.7.

8. The method according to claim 1 , the solvent being selected from water, a polyol and mixtures thereof.

9. The method according to claim 8 , the solvent being a polyol selected from 1,2-propanediol, ethylene glycol, diethylene glycol and mixtures thereof.

10. The method according to claim 1 , the stabilizing agent being selected from anionic surfactants, amphoteric surfactants, cationic surfactants, non-ionic surfactants and mixtures thereof.

11. The method according to claim 10 , the stabilizing agent being selected from polyvinylpyrrolidone, polyacrylic acid, sodium tricitrate, and mixtures thereof.

12. The method according to claim 1 , the destabilizing agent being selected from water, a ketone and mixtures thereof.

13. The method according to claim 1 , the elimination of solvent in step b) comprising evaporation and/or decomposition of the solvent.

14. The method according to claim 1 , step b) for eliminating the solvent being carried out at a temperature of less than 200° C.

15. The method according to claim 1 , step c) for debinding and sintering being carried out at a temperature of less than 200° C.

16. The method according to claim 15 , the sintering being carried out at a temperature of 100° C. or more.

17. The method according to claim 1 , in which the first component and/or the second component of the electronic system are selected from a support, a chip produced from a semiconductor material, a light emitting diode, a component of an electronic power system.

18. The method according to claim 1 , in which more than 95.0% of the mass of the metal nanoparticles is constituted by silver.

19. The method according to claim 1 , in which the solvent is selected from water, 1,2-propanediol, ethylene glycol, diethylene glycol and mixtures thereof and the stabilizing agent is selected from anionic surfactants, amphoteric surfactants, cationic surfactants, non-ionic surfactants and mixtures thereof.

20. The method according to claim 1 , wherein the sintering solution further consists of at least one of a texturing agent and metal microparticles.

21. The method according to claim 1 , comprising debinding and sintering the interconnection layer at a temperature of less than 200° C. and greater than or equal to 100° C.

Assignees

• Commissariat Energie Atomique
• Commissariat A Lenergie Atomique Et Aux Energies

Inventors

• Feautrier Céline
• Bronchy Maxime

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10W99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F3/15

  Hot isostatic pressing · CPC title

• B22F3/24 Primary

  After-treatment of workpieces or articles {(B22F3/1146 takes precedence)} · CPC title