International Business Machines Corporation

Leroy N Chellis

Theron L Ellis

Robert Maynard Japp

David W Wang

William John Rudik

William J Summa

A flame retardant, low dielectric constant, controlled coefficient of thermal expansion, low cost prepreg material which includes randomly distributed silane coated hollow microspheres has been prepared by standard impregnation and lamination techniques. Laminates made of this prepreg can be drilled cleanly for through holes and can be used as a substrate for surface mounted devices.

Flame retardant, low dielectric constant microsphere filled laminate

At least two conductors are electrically connected through a dielectric material by providing a dielectric material having a first conductor on a first surface thereof and a temporary support layer covering the first conductor and the first surface of the dielectric material. A second surface on the dielectric material opposite the first surface is provided with a second conductor and a temporary support layer covering the second conductor and second surface of the dielectric material. Interstitial through-holes are provided to connect the first and second conductors. The through-holes are plated with an electrical conductor to thereby electrically connect the first and second conductors. The support layers are then mechanically removed such as by peeling to thereby provide a landless electrical connection between the first and second electrical conductors.

Process for providing a landless through-hole connection

A composition suitable for making circuitboards containing two different brominated epoxy polymeric components which are brominated diglycidyl ethers of bisphenol-A and epoxidized nonlinear novolak having at least about six terminal epoxy groups.

Product containing an epoxy composition

Process of laminating with an epoxy composition

Epoxy composition

A multi-layered printed circuit board is disclosed having a plurality of circuitized laminations therein. The laminates are fabricated or secured by curing layers of glass cloth which have been impregnated with heat curable resins at temperatures in excess of their glass transition temperature, the point at which such material begins to distort. Those laminations which will see at least one further curing cycle, after having themselves been cured, are formed from glass cloth impregnated heat curable resin combinations having a glass transition temperature which is significantly higher than that of the heat curable materials employed to form the subsequently and singly cured laminations. In this manner, lamination shift or distortion is appreciably reduced since those laminations which undergo a plurality of 'curing' cycles, only experience one excursion beyond their transition temperature. Thus, registration mismatch between any of the circuitized laminates will not exceed acceptable levels.

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Endwell, NY, United States of America

Leroy N Chellis