Ingrown lead frame with strain relief

Abstract From the Canadian patent

A method for providing a large number of interconnections between a circuitizable wafer and a circuitizable substrate provides very fine line interconnections with built-in strain relief. A channel between the respective substrates is filled with a solvent soluble material which is applied in a manner such that a convex or concave shape is attained in the channel between the material. A sensitizer may be mixed with the solvent soluble material prior to its placement in the channel between the substrates and, then a photoresist is applied to the composite exposed, and developed, yielding the desired circuit configuration. Next copper leads are additively electrolessly plated to the desired …