Method for making 3-D electrical circuitry

A method of forming three-dimensional electrical circuitry having conductive components and at least one pointed projecting feature projecting from said components comprising:

• forming an electrically conductive mandrel having a working surface,
• forming a pattern of electrically non-conductive material of said mandrel, said material having a non-conductive material surface that divides said mandrel working surface into an electrically conductive pattern,
• forming a depression in said mandrel working surface having a configuration that tapers from a broad area at said surface to a smaller area below said surface to define a pointed mandrel feature,
• electroforming a pattern of conductors and a pointed circuit feature on the conductive pattern of said working surface and in said pointed mandrel feature,
• laminating a dielectric material upon said mandrel, upon said pattern of conductors and upon said pointed circuit feature to position said dielectric material over said conductors and circuit feature, whereby said conductors are bonded to said dielectric material and whereby said pointed circuit feature projects from said conductors,
• separating said dielectric material with said electroformed conductors and pointed projecting circuit feature from said mandrel substrate and its non-conductive material to provide a laminate of dielectric material having conductors thereon and a pointed circuit feature projecting from said conductors,
• forming a circuit for connection to said laminate of dielectric material and pointed circuit feature including the step of forming a conductively plated hole in said circuit having radially outwardly extending conductive flanges with corners at inner ends of the flanges, and
• pressing said laminate of dielectric material and its pointed circuit feature against said last mentioned circuit to cause said pointed circuit feature to partly enter said plated hole and to deform said corners to effectively provide a wiping and wedging action to ensure good electrical contact between said plated hole and said pointed circuit feature.