(1) For the chip manufacturing company, see
Substrate chip company.
(2) The base layer of a structure such as a chip, multichip module (MCM), printed circuit board or disk platter. For chips, silicon is the most widely used substrate. Fiberglass (FR4) is mostly used for printed circuit boards, and ceramic is used for multichip modules (MCMs). Hard disk substrates are typically aluminum and glass, and optical disc substrates are plastic.