Abstract: A printed circuit board is provided with via holes and these holes are provided with a base coat of conductive metal, a coating of insulating material deposited on said base coat, and a second coat of conducting metal deposited on said insulating material. The metal coatings are interconnected to one or more surfaces of the board and the base coat is connected to at least one internal power, ground or signal plane. This via hole construction facilitates the making of engineering changes by simply deleting the interconnection between the metal coatings at the board surface and subsequently connecting the desired point to an alternate point on the circuit board.

Abstract: A polysulfone base stop resist material to protect gold thermocompression bonding sites on a circuit module during a solder dipping operation. Along with the thermoplastic, thermostable strippable base of polysulfone, the resist includes a solvent for the polysulfone and a filler which holds the melted polysulfone in place during the solder dipping operation.