Hi there, I'm also looking for an answer to a certain question and it looks like it has already been discussed in the following old KX topics
"Multiple layers of Metal Contacts CHARGE" July 3, 2019
"DEVICE: Two contacts are adjacent, modeling several materials in metal contact" (can't obtain date from google search)
Unfortunately I couldn't find the direct links to the topics any more.
It would be great if you could repost these topics, if that doesn't work any other form of help would be greatly appreciated :)