The problem with other metals is that they oxidize when sintered in air. Only silver, gold, and the platinum metals other than osmium do not oxidize in air at the temperatures required for sintering. Silver is the cheapest of these metals, so it is the most commonly used.

Dear Qun Ye thank you for posting this interesting technical question on RG. In addition to the expert answer provided by Vadim Verlotski please also have a look at the following potentially useful literature reference which might help you in your analysis:

Die Attach of Power Devices Using Silver Sintering - Bonding Process Optimization and Characterization

https://hal.archives-ouvertes.fr/hal-00672619/document

This paper is freely available as public full text. It is stated here that (citation): "Silver is usually chosen as the metal, because of its excellent thermal and electrical performances, its reasonable price and its low temperature sintering capability."

Also please see the following closely related Open Access paper:

Properties of a novel silver sintering die attach material for high temperature - high lifetime applications

(see atached pdf file).

Good luck with your work!

Hello Qun Ye ,

There are a host of reasons to use silver in sintering pastes in electronics: 1) silver has the highest electrical conductivity of all metals [1], 2) the highest thermal conductivity of all metals [2], and 3) the highest thermal diffusivity of all metals [2]. For establishing electrical connections (in a hermetically sealed environment since it readily tarnishes when exposed to sulfur and hydrogen sulfide) and removing heat, you can't beat silver

[1] Charles Kittel; Introduction to Solid State Physics Fourth Edition; John Wiley & Sons, Inc; 1971; p. 260.

[2] Frank P. Incropera, David P. De Witt; Fundamentals of Heat and Mass Transfer, Second Edition; John Wiley & Sons, Inc; 1985; pp. 755-758.

Regards,

Thomas Cuff

Hello Qun Ye ,

Is the silver in the paste pure silver or is it alloyed with some other metal to reduce its melting point?

Regards,

Thomas Cuff