Method and apparatus for forming multi-layered circuits using liquid crystalline polymers

Abstract

A method and apparatus for producing high layer count, multi-layer circuits which includes fabricating a fixture having an opening therein for placement within a press. A material stack, particularly a material stack having multiple layers of liquid crystalline polymer, is placed within the opening of the fixture before activating the press to laminate the material stack positioned within the fixture.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional patent application based on utility patent application entitled “METHOD AND APPARATUS FOR FORMING MULTI-LAYERED CIRCUITS USING LIQUID CRYSTALLINE POLYMERS” and having Ser. No. 11 / 187,220, filed Jul. 22, 2005, which is herein incorporated in its entirety.FIELD OF INVENTION [0002] This invention relates, generally, to a method and apparatus for forming multi-layered circuits and, in particular, to a method and apparatus for forming high layer count circuits comprising liquid crystalline polymer insulating or dielectric layers. BACKGROUND OF THE INVENTION [0003] Multi-layered circuit boards are typically fabricated from layers of distinct circuit patterns separated by insulating material such as thin dielectric layers and interconnected by vias, or holes, that are drilled through the circuit board and plated with metal. It is desirable to interconnect integrated circuit packages and discrete electronic devi...

AI Technical Summary

Benefits of technology

[0009] In accordance with one aspect of the present invention, an apparatus for forming multi-layered circuits is provided which includes a press having top and bottom platens capable of applying pressure to a material stack located between the platens and a fixture positioned between the platens having an opening therein in which to position the material stack. The fixture functions to limit or control the pressure applied to the material stack which in turn results in a laminated material stack having a uniform thickness.

Problems solved by technology

However, the number of layers comprising multi-layered circuit boards becomes limited due to the increased non-uniformity in thickness and high fluid flow as more layers are added.

This non-uniform pressure distribution results in a multi-layer stack having a non-uniform thickness and conductor layer feature shifting.

In addition, it becomes difficult to drill and plate the interior surfaces of the vias within the non-uniformity of the multi-layer stack.

This non-uniformity also becomes a performance issue at high frequencies.

Current methods for fabricating multi-layer stacks of liquid crystalline polymers with copper foil are not capable of limiting feature shifting in the various layers and / or controlling or limiting the pressure applied to the multi-layer stacks during lamination.

As a result, the number of layers that can be laminated to form a multi-layer circuit is limited in order to avoid feature shifting and non-uniformity in the thickness of the multi-layer stack.

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