International Business Machines Corporation

Yaffa Tomkiewicz

Edward M Engler

Robert G Schad

John D Kuptsis

Thomas Anthony Wassick

Jerry E Hurst, Jr

John J Ritsko

James T Yeh

Warren D Grobman

Thomas Carl Clarke

John J Donelon

Fahfu Ho

Neng H Lu

Ho M Tong

A method is disclosed for the manufacture of void-free prepregs formed by the impregnation of a reinforcing cloth (e.g. glass fiber cloth) with a solution of a thermosetting resin (e.g. epoxy resin). In the method, the reinforcing cloth is first prewetted with a liquid medium containing a solvent for the resin which has a viscosity less than that of the solution of thermosetting resin. The prewetted cloth is impregnated with a solution of the resin and then heated to remove the solvent and cure the resin. The prepregs are used in the manufacture of printed circuit boards.

Process for the production of void-free prepreg sheets

A differential material removal process wherein a selected material can be rapidly removed without adverse impact to surrounding layers of different materials. Ultraviolet radiation is used to selectively remove metal without adversely harming adjacent polymer layers, in a metal-polymer multilayer structure. The wavelength (100-400 nm) of the ultraviolet radiation and the energy fluence per pulse are selected so that the removal rate of metal due to thermal processes is significantly greater than the removal rate of the polymer by ablative photodecomposition. This can occur at an energy fluence per pulse level greater than that at which the etch rate of the polymer begins to level off. For example, copper of a thickness less than 5 microns is rapidly etched in one or two pulses while adjacent polyimide layers are substantially unetched by the application of ultraviolet pulses of wave-lengths 248-351 nm, at energy fluences per pulse in excess of approximately 3 or 4 J/cm.sup.2.

Selective metal etching in metal/polymer structures

A method of radiation induced dry etching of a metallized (e.g. copper) substrate is disclosed wherein the substrate is pattern-wise exposed to a beam of laser radiation in a halogen gas atmosphere which is reactive with the substrate to form a metal halide salt reaction product to accelerate the formation of the metal halide salt without its substantial removal from the substrate. The metal halide salt is removed from the substrate by contact of the substrate with a solvent for the metal halide salt.

Laser stimulated halogen gas etching of metal substrates

Novel E-beam resists and process for their use are described. These resists are conducting organic charge transfer salts. Films of these materials can be deposited by solvent casting or by sublimation. The deposited film can be made to produce a positive or negative resist image depending on the E-beam energy and exposure time. Exposure of this material to an E-beam produces patterns having differential electrical, optical and solvation properties.

Class of E-beam resists based on conducting organic charge transfer salts

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Scarsdale, NY, United States of America

Yaffa Tomkiewicz