[alfor]

Does wisker form inside semiconductor also or do they use metals immune to that?

[hulitu]

Yes they do but slower. In the past gold was used for wires from terminal to pads. Gold as far as i know is not so subceptible to form whiskers. But gold is expensive and now they use copper instead of gold.

[askvictor]

Unfortunately, gold is also susceptible: https://nepp.nasa.gov/whisker/other_whisker/gold/index.htm