Hughes Aircraft Company

Packard Hughes Interconnect Company

David Bryan Swarbrick

Haim Feigenbaum

William R Crumly

Christopher M Schreiber

Bao Le

Oswaldo Ernesto Caballero

Jack H Pike

A process using a shim stock or foil to make flexible circuits having raised pressure contact features protruding outwardly from two surfaces. A first set of raised electrical pressure contact features are made by placing a shim stock or foil of stainless-steel on a piece of soft metal or other suitable substrate and forcing a tool into the foil to form dimples in one face. Thereafter, the foil is turned over and the process repeated on the other face of the foil. The resultant foil includes a first face having a first dimple and a first bump extending outwardly from the first face. A flash coating is formed on the foil and electrical traces are deposited on the first face of the foil including into the first dimple and over the first bump. A dielectric substrate is selectively deposited over the electrical traces and the complete subassembly is removed from the foil. A flash coating is etched away and optionally a second dielectric substrate is selectively deposited over the electrical traces. The resulting flexible circuit has raised features protruding from two surfaces.

Method of making a flexible circuit with raised features protruding from

The present invention generally includes a process in which a mandrel for semi-additive construction of circuitry is fabricated by laminating shim stock or foil of stainless steel onto a suitable deformable substrate such as a polyimide glass board. Dimples for making raised features on circuitry are formed in the mandrel with a tool. The use of shim stock makes the mandrel relatively light and suitable for automated processing similar to that used to construct circuits on circuit boards.

Method of making mandrels and circuits therefrom

A membrane test probe (10) for use in testing integrated circuit chips (50) has a thin flexible membrane (30) bearing test contacts (40,42) that is stretched across an opening of a rigid-flex substrate (12). The membrane is manufactured with uniform radial tension by a lamination fixture having a steel pressure plate (76) that includes an annular groove (78). A high temperature O-ring (80) is positioned in the groove against the radially inner wall (82) of the groove with the radially outer wall of the groove being displaced from the outer part of the O-ring. The O-ring has a thickness greater than the depth of the groove and when the steel pressure plate is pressed against the membrane to press it against its substrate the O-ring pushes a portion (92) of the membrane into a shallow groove (16) in the substrate and deforms radially outwardly. As the O-ring deforms radially outwardly, it exerts a radially outwardly directed tension on the membrane which is cured in this radially stretched condition.

Radial tensioning lamination fixture for membrane test probe

A circuit is produced by using a formed mandrel (10,12) and semi-additive techniques for creating circuit traces. A stainless steel mandrel (10) flash plated with copper (14) includes a depression (12) which will form a raised interconnection feature (24). Using a photolithographically formed pattern of photoresistive material (16) on the mandrel the selected pattern of circuit traces (18,20) and raised features (24) are electroplated onto the flash plated mandrel. After stripping the photoresist (16), a dielectric substrate (26) is laminated to the circuit traces, effectively encapsulating the traces on three sides. After removing the laminated circuit traces and dielectric from the mandrel the flash plated copper (14) is removed and the circuit covered with an insulation coverlay.

Semi-additive circuitry with raised features using formed mandrels

A pressure type contact (10) for flexible or conventional wire cable terminations is fabricated from electroformed thin metallic wafers in which one wafer is plated with a raised conductive interconnection feature. The raised feature is formed by placing a small lump (44) of electrically conductive resin on a substrate (12) and then electrolytically forming on the substrate a trace (18) having an enlarged connector pad (20) that completely covers the cured projecting resin lump.

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Mission Viejo, CA, United States of America

David Bryan Swarbrick