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Formation of Surface Laminar Circuit on Printed Circuit Board with Plated through Holes

IP.com Disclosure Number: IPCOM000106328D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Tsuchita, S: AUTHOR [+2]

Abstract

Disclosed is a composite structure comprising a surface laminar circuit (SLC) and an epoxy-glass printed circuit board with plated through holes (PTH). The through holes of the board are filled with resin to permit the formation of high density SLC wiring over the PTH regions.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 91% of the total text.

Formation of Surface Laminar Circuit on Printed Circuit Board with Plated through Holes

      Disclosed is a composite structure comprising a surface laminar
circuit (SLC) and an epoxy-glass printed circuit board with plated
through holes (PTH).  The through holes of the board are filled with
resin to permit the formation of high density SLC wiring over the PTH
regions.

      The SLC is a multilayer wiring structure formed on the surface
of a rigid printed circuit board through the use of photoprocess.
Interlayer connections in the SLC are made by photoprocessed vias,
enabling very high density wiring.  The combination of the SLC with a
conventional PTH printed circuit board will permit optimized wiring
performance because the SLC can be used for the formation of a high
density and high performance wiring portion while the PTH board can
be used for the formation of the remaining wiring portion.  This
disclosure provides a way to form the SLC structure on a PTH board.

The SLC/PTH composite structure can be manufactured in the following
process steps:

1.  Prepare a PTH board such as a conventional glass-epoxy multilayer
    printed circuit board
2.  Fill the PTH's of the board with epoxy resin
3.  Polish the surface of the board to have a smooth top surface
4.  Form an SLC structure on the board
    o   Coat a photosensitive epoxy resin layer on the board
    o   Expose the photosensitive layer in a desired via pattern and
        develop i...