What is the material on top of the chips in this logic board, and should I leave them?

Question

This is a very beginner-ish question. I didn't know where else to ask, or even what terms to search for, so I hope this is the right place.

I'm replacing the logic board on a monitor.

The replacement board came with this gray material covering all the delicate parts (see image; one has the position skewed on purpose).

What is it? Was it for protection in packaging, or is it a heat conducting material?

Should I leave them all, or remove a few?

It's clear that a couple were left on the original board, but not as many as came attached to the replacement.

Thanks!

Answer 1

They're to protect the IC package against mechanical impact. Total height of such an IC may be less than 1 mm, so you can imagine the top of the package is only a couple of tenths of a mm thick. A sharp object will go right through it and destroy the die.

Looks overkill to me. The photo shows bubble foil too, and there's usually a few cm between board and the carton box. If during handling a sharp object can penetrate 3 cm deep into the carton, and still have enough energy to break the IC's package your handling process really needs a critical review.

Also the rest of the board isn't protected. That same sharp object may scratch the PCB, cutting traces, or chip off a small SMT capacitor.

You can throw them away.

Answer 2

I am not positive but I think that's just protection and not a thermally conductive foam material like this. I would not expect a logic board to need thermally conductive foam.