High-density, multi-level interconnects, flex circuits, and tape for tab
Patent 5106461 Issued on April 21, 1992. Estimated Expiration Date: December 21, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
205/125, Product is circuit board or printed circuit257/E23.173, Multilayer substrates (EPO)257/E23.174, Conductive vias through substrate with or without pins, e.g., buried coaxial conductors (EPO)257/E23.177, Flexible insulating substrates (EPO)438/616, By transcription from auxiliary substrate438/667, Conductive feedthrough or through-hole in substrate438/678, Electroless deposition of conductive layer438/977THINNING OR REMOVAL OF SUBSTRATE
A multi-layer interconnect structure of alternating dielectric (e.g., polyimide) and metal (e.g., copper) is built on a substrate supporting a continuous layer of metal. This metal layer is used as an electrode for plating vias through all the dielectric layers. Once the desired number of layers are formed, the substrate is removed and the continuous metal layer is patterned. Solid metal vias having nearly vertical side walls can be stacked vertically, producing good electrical and thermal transfer paths and permitting small, closely-spaced conductors. Further, by mixing geometrical shapes of conductors, a variety of useful structures can be achieved, such as controlled impedance transmission lines and multiconductor TAB tape with interconnects on tape of different dimensions than TAB fingers.
Adams et al., "High Density Interconnect for Advanced VLSI Packaging", Suss Seminar Series, 1987, pp. 1-8
Barrett, "High Definition Electroplated Copper Conductors on Silicon and Ceramic", IMC Proceedings, May 25-27, 1988, pp. 461-467
Hatada et al., "New Film Carrier Assembly Technology: Transferred Bump TAB", IEEE, Sep. 1987, pp. 335-340
Heikkila, "Precision Plating: A Fundamental Approach", Economics Laboratory, Inc