Abstract: Metallized via-holes and a wraparound metal plating are simultaneously formed on semiconductor chips by patterning a photoresist mask on the front surface of the wafer to open windows over metal pads as well as the grid areas where wraparound plating is desired; etching off the exposed metal if necessary and forming via-holes and grooves in the wafer by reactive ion etching to a depth which is less than the total thickness of the wafer; depositing a thin conductive film along the walls of the grooves and via-holes by electroless methods; plating the walls of the grooves and the via-holes with conductive metal by electrolytic methods; removing the back surface of the wafer ("backlapping") along with the floors of both the grooves and the via-holes, to expose the metal on the wall of the via-holes and separate the individual chips; and, depositing conductive metal on the back surface of the individual chips to complete the grounding path.

Abstract: A method for simultaneous selective plating of viaholes and heat sinks associated with a semiconductor wafer using a metal mask and comprising the steps of:(a) coating a first side of the wafer with an insulating layer to prevent electroplating on this first side;(b) patterning on a second side of the wafer, opposite to the first side, a metal mask for defining the areas where plating should not occur;(c) forming via-holes through said wafer;(d) depositing a thin conductive film to coat the bottom and walls of the via-holes as well as areas of the second side of the wafer not covered by the metal mask; and(e) electrolytically plating the resulting wafer while ultrasonically agitating the electrolyte if necessary to ensure sufficient electrolyte transport into the via-holes for uniform plating.

Abstract: A method is disclosed for forming completely metallized via holes in semiconductor wafers. Metal pads are formed on one face of a semiconductor wafer together with a conductive interconnecting network. An insulating layer is then deposited to cover this face of the wafer. Holes are etched in the opposite face of the wafer up to and exposing a portion of the metal pads. The via holes are then completely filled with metal by means of electroplating, using the metal pads as a cathode.