Browse Prior Art Database

High Circuit Density 3-D Molded Card Fabrication Process

IP.com Disclosure Number: IPCOM000102817D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Lauffer, JM: AUTHOR [+2]

Abstract

Disclosed is a process for high circuit density, fine line molded card fabrication with extendibility to three-dimensional (3-D) circuitry. The key advantage, as described below, is the utilization of standard subtractive processing, without the requirement of photomasking or elaborate 3-D imaging.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 85% of the total text.

High Circuit Density 3-D Molded Card Fabrication Process

      Disclosed is a process for high circuit density, fine line
molded card fabrication with extendibility to three-dimensional (3-D)
circuitry.  The key advantage, as described below, is the utilization
of standard subtractive processing, without the requirement of
photomasking or elaborate 3-D imaging.

      The molded card substrate is fabricated through conventional
molding operations, where the mold has been designed such as to
provide recessed circuitry.  Following the molding operation, the
substrate is adhesion treated, electroless copper plated and finally,
acid copper plated to the desired circuit line thickness.  The plated
substrate is then dip or spin coated with a low viscosity,
planarizing photoresist, and soft-baked.  Resist planarization is
essential in order to provide a thicker resist over the recessed
circuit lines.  The part is then processed through an oxygen plasma,
which provides a uniform resist removal rate.  Plasma etching is
terminated at the point where the resist has been completely removed
from the raised substrate areas, but still remains over the circuit
lines.  The substrate is then subtractively etched via conventional
copper etching techniques with the photoresist protecting the desired
circuit lines from etching.  Following photoresist stripping, the
molded circuit card is ready for surface mount assembly of
components.  Protective coating of circuit lines is not...