At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

David J Lando

Lawrence Arnold Greenberg

Frederick R Wight, Jr

Printed circuit boards having a plurality of circuit layers are produced using a specific processing sequence. A copper-clad substrate is first patterned in a desired configuration to produce the first layer of the printed circuit board. The patterned metallization is then covered with a specifically formalated energy sensitive material. The energy sensitive material is delineated in a desired pattern and developed to uncover portions of the underlying metallization pattern. The entire substrate is blanket-cured to produce a rigid layer having openings in appropriate places. The openings are metallized and a second copper pattern is produced on the cured polymer by conventional metallization and lithographic techniques. If desired, the process is repeated until a suitable number of copper patterned levels are obtained.

Circuit board fabrication leading to increased capacity

Disclosed is a semiconductor package which permits coupling of semiconductor bond pads to I/O leads where a high density of connections is needed. Conductive fingers backed by an insulating tape are bonded to the ends of the fingers on a lead frame. The tape fingers are electrically coupled to the bond pads on one major surface of the semiconductor chip by wire bonding. In one embodiment, the opposite major surface of the chip is bonded to a paddle on the lead frame through an aperture in the tape for maximum heat dissipation.

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Allentown, PA, United States of America

David J Lando