Via and pad structure for thermoplastic substrates and method and

Abstract

An improved connection through a substrate layer is formed by embedding a conductive element such as a pin on one or more balls or spheres in a thermoplastic material which is preferably a liquid crystal polymer. The substrate may be heated to facilitate the embedding process in which material of the substrate layer is reflowed under pressure to retain the conductive element by means of a preload force. The formation of such connections with either pins or plural conductive elements allows independence of aspect ratio of the connection and, hence, feature size of conductive patterns on the substrate and the thickness of the substrate layer. Perfecting features of the substrate and method and apparatus for forming the substrate, embedding to a selected depth to form protrusions and recesses to assist in registration of a substrate layer with another substrate layer, metallization to form pads, improved connection between metallization patterns on the substrate and the conductive elements, the regulation of pressurization of substrate material by means of differently shaped dimples or a renewable surface and several alternative arrangements for positioning and embedding the conductive elements. Multiple types of conductive elements may be simultaneously embedded to different depths in a single substrate and from either or both sides thereof to form a variety of substrate structures.