Method for making circuit connections to internal layers of a multilayer circuit card and circuit card produced thereby

Claim 1

A MULTILAYER CIRCUIT BOARD HAVING SELECTIVE CONNECTIONS TO INTERNAL LAYERS THEREOF COMPRISING: (A) MULTIPLE CIRCUIT BOARD LAYERS EACH COMPRISING A LAYER OF INSULATING MATERIAL HAVING A CIRCUIT CONFIGURATION OF ELECTRICALLY CONDUCTIVE MATERIAL ON THE SURFACE THEREOF, SAID LAYERS BEING LAMINATED TOGETHER, SAID CONDUCTIVE MATERIAL ON AT LEAST EACH OF SAID INTERNAL LAYERS HAVING A VOID THEREIN EQUAL IN SIZE TO THE VOIDS IN THE CONDUCTIVE MATERIAL ON EACH OF THE OTHER OF SAID LAYERS, SAID VOIDS BEING ALIGNED ALONG A SELECTED AXIS NORMAL TO SAID BOARD, A HOLE EXTENDING THROUGH THE MULTILAYER CIRCUIT BOARD ON AID AXIS, SAID HOLE BEING OF VARYING DIAMETER ALONG SAID AXIS, SAID HOLE AT A RELATIVELY LARGE DIAMETER PORTION THEREOF INTERSECTING THE CONDUCTIVE MATERIAL DEFINING ONE OF SAID VOIDS ON ONE OF SAID INTERNAL LAYERS, SAID HOLE AT A RELATIVELY SMALL DIAMETER PORTION THEREOF PASSING THROUGH AN ALIGNED VOID IN THE CONDUCTIVE MATERIAL ON ANOTHER OF SAID LAYERS AND BEING SPACED FROM THE SURROUNDING CONDUCTIVE MATERIAL, AND CONDUCTIVE MATERIAL LINING SAID HOLE TO MAKE A SELECTIVE ELECTRICAL CONNECTION WITH AT LEAST ONE OF THE INTERNAL LAYERS OF CONDUCTIVE MATERIAL.