Printed circuits prepared from filled epoxy compositions

Abstract

Compositions and processes for the preparation of printed circuits from epoxy compositions are provided. The epoxy compositions exhibit low viscosity in the uncured state and low coefficient of thermal expansion in the cured state. The low dielectric constant compositions of the invention are well-suited for use in multi-layer printed circuit boards.

Description

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents a finished electronic component according to the present invention, including an IC chip mounted upon a multilayer circuit, which circuit in turn rests on a substrate or mother-board.

FIG. 2 represents the steps for preparing multilayer printed circuits according to an embodiment the present invention.

Claims

1. A printed circuit comprising a dielectric substrate and a plurality of discrete conductive pathways disposed thereupon; said dielectric substrate comprising a film or sheet comprising the cross-linked reaction product of an aromatic epoxy and an aromatic cross-linking agent, and 20 to 60% by weight relative to the weight of said cross-linked reaction product of a particulate mixture comprising silica dispersed therein, said particulate mixture characterized by a bimodal particle size distribution of nanoscale particles.

2. The printed circuit of claim 1, wherein said aromatic epoxy is an o-cresol novolac and said aromatic cross-linking agent is a phenol or an anhydride.

3. The printed circuit of claim 1, wherein the particulate mixture comprises a smaller particle population and a larger particle population, the smaller particle population representing 10-30% by weight of the total weight of the particulate mixture.

4. The printed circuit of claim 3, wherein the smaller particle population consists essentially of fumed silica.

5. The composition of claim 3, wherein the larger particle population consists essentially of spherical silica or nano-clay.

6. A process for preparing a printed circuit, the process comprising laminating copper to a film or sheet, applying a photoresist to the surface of said copper, imagewise exposing said photoresist to light, and developing said imagewise exposed copper layer, thereby forming a plurality of discrete copper conductive pathways disposed upon said film or sheet, said film or sheet comprising the cross-linked reaction product of an aromatic epoxy and an aromatic cross-linking agent, and 20 to 60% by weight relative to the weight of said cross-linked polymer network of a particulate mixture dispersed therein, said particulate mixture characterized by a bimodal particle size distribution of nanoscale particles.

7. The process of claim 6, wherein said aromatic epoxy is an o-cresol novolac and said aromatic cross-linking agent is a phenol or an anhydride.

8. The process of claim 6, wherein the particulate mixture comprises a smaller particle population and a larger particle population, the smaller particle population representing 10-30% by weight of the total weight of the particulate mixture.

9. The process of claim 8, wherein the smaller particle population consists essentially of fumed silica.

10. The composition of claim 8, wherein the larger particle population consists essentially of spherical silica or nano-clay.