Hermetically sealed printed circuit board

摘要

The invention relates to an improvement in dielectric type printed circuit boards having wells for mounting active circuit components on a metal substrate for heat dissipation. The improvement resides in a hermetic seal for the printed circuit board which includes a lid hermetically sealed to the top surface of the circuit board, as well as a chemically vapor deposited coating on the dielectric around the active components to prevent seepage of water and oxyen through the lid edges and into the well regions which would otherwise be detrimental to the active components.