International Business Machines Corporation

John P Wiley

Joseph G Hoffarth

Donald J Lazzarini

John A Welsh

Voya Rista Markovich

Chi Shih Chang

Keith A Snyder

Robert T Wiley

Cynthia J Broaddus

Eugene M Scales

Carl C Sissenstein

John R Jephson

A multilayered circuit board assembly which includes a plurality of layered subassemblies each having electrically conducting wiring and at least one through hole therein. A first of these subassemblies possesses a greater wiring dnesity than the others while a second subassembly possesses a lesser resistance (and wiring density) than the others. In one example, several (e.g. at least four) such layered subassemblies may be included in the overall assembly such that those layers located along one side of the board may possess substantially greater wiring densities than the layers on the other side of the board while those layers on said other side will in turn possess lesser resistance (and greater current capacities). There are also described at least three methods for making the above multilayered circuit board assembly. Such a structure may be utilized in supercomputer applications.

High density circuit board and method of making same

A method is disclosed for providing less critical alignment of vias and through holes and lower bonding stresses in the manufacture of high density circuit boards. In the invention, a via is drilled through a land which is in a plane separate from that of the signal plane.

Bondable via

A multilayer circuit board having a conformal layer of an insulating material separating a circuit core from an adjacent insulating layer is disclosed. The conformal layer encapsulates the substrate and conductive pattern of circuit lines in the circuit core, thereby reducing failures caused by impurities trapped during lamination. The multilayer circuit board is manufactured by coating at least one circuit core with the conformal layer of insulating material before final lamination of the circuit cores into a multilayer circuit board.

Method of making multilayer circuit boards having conformal Insulating

Multilayer circuit board with reduced susceptability to shorts caused by

An electrically conductive circuit member for use within a multilayered circuit board assembly wherein the member comprises a sheet of electrically conductive material (e.g., copper) and first and second layers of electrically insulative material (e.g., prepreg) bonded thereto to substantially encapsulate the conductive material therein. The conductive material includes a plurality of apertures and a plurality of elongated openings, which openings are mechanically provided in a predefined pattern to assure at least two electrically isolated regions within the singular, planar conductive material. A method of making this circuit member is also defined, said method not requiring the need for wet/chemical processing and the disadvantages associated therewith.

Circuit member for use in multilayered printed circuit board assembly

The invention features a method of fabricating a printed circuit board having improved circuit board performance. The circuit board utilizes low dielectric materials having dielectric constants of less than 3.0. The dielectric layers are spaced apart from plated through-holes, thus eliminating the interface between the metallized surface of the through-hole and the dielectric sheet. Thus, the low dielectric layer is not required to be plated. The lower dielectric character of the laminates improves wiring density, circuit speed, and provides for thinner laminates and cores.

High performance circuit boards

The invention features a method of fabricating a printed circuit board with low dielectric materials using a modular technique. Sub-assemblies are first constructed, tested, and then subsequently incorporated into the final circuit board assembly which has a triplate geometry. Dielectric materials are chosen which enhance the performance of the circuit board.

Low dielectric printed circuit boards

The invention features a method of fabricating a printed circuit board using a modular technique. Sub-assemblies are first constructed, tested, and then subsequently incorporated into the final circuit board assembly which has a triplate geometry. Lamination of the modular sub-assemblies minimizes dielectric core thickness.

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Vestal, NY, United States of America

John P Wiley