Browse Prior Art Database

Joining Layer Fabrication by Mechanical Punching or Drilling

IP.com Disclosure Number: IPCOM000103157D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Gall, TP: AUTHOR [+4]

Abstract

Disclosed is a process for producing a thermoplastic low dielectric film for insulation a layer of printed circuitry while providing plated metal vias for electrical connections to the next circuit layer in a stack.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 73% of the total text.

Joining Layer Fabrication by Mechanical Punching or Drilling

      Disclosed is a process for producing a thermoplastic low
dielectric film for insulation a layer of printed circuitry while
providing plated metal vias for electrical connections to the next
circuit layer in a stack.

      Teflon* and silica-filled teflon are excellent low dielectric
constant materials for making printed circuit cards for high
temperature (up to 390¯C) applications. There are, however, two major
problems to be faced when processing teflon:  it is soft, so thin
films will not keep a precise shape (necessary for aligning fine line
patterns), and it is not easily shaped by photoprocesses.  These
problems can be solved by coating the teflon on to a stable carrier
foil, such as Copper-Invar*-Copper, and mechanically forming a
pattern of via holes in the film.

      The figure shows two alternative processes for producing the
joining layer.  A teflon dispersion is sandwiched between two layers
of carrier foil, densified into a film in a high temperature press,
then the foil is etched off one side.  Once holes have been punched
(or drilled) through the polymer and carrier foil, a conductive
surface for via metal plating is provided either by filling the holes
in the carrier foil with solder, or by laminating a fresh metal layer
to the polymer side and etching off the perforated carrier foil.  The
via joining metal is electroplated in the holes up to the surface of
the polymer.

 ...