International Business Machines Corporation

Gisbert Gerhard Thomke

Erich Klink

Anand Haridass

William Frederick Shutler

Dierk Kaller

Simone Rehm

Bernd Garden

A method for increasing the wiring channels/density under dense via fields of a circuit board are provided. With the method, the power/ground lines for the circuit board are designed to be provided in an orthogonal or diagonal pattern. The land grid array (LGA)/ball grid array (BGA) makes contact only on the surface pads of the printed circuit board with no plated through holes/vias underneath these surface pads. This opens up wiring channels, which previously used to be occupied by plated through holes and anti-pads, that can now be used for maximizing signal line wiring routing.

Method for increasing wiring channels/density under dense via fields

Disclosed is a multilayer electronics packaging structure, especially for use in a multi chip module. By forming an overlap of signal conductors by the respective mesh conductors, an improved shielding effect is achieved and coupling between signal conductors is reduced. By increasing the via punch pitch such that multiple wiring channels are formed between adjacent vias, wirability is improved and the number of signal distribution layers may be reduced. The new structure thus shows improved electrical properties over the state-of-the-art structures, combined with a cost reduction of about 35%.

MCM&mdash;MLC technology

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Schoenaich, Germany

Gisbert Gerhard Thomke