Browse Prior Art Database

Fabrication of Multi-Channel through Holes without Copper Plating

IP.com Disclosure Number: IPCOM000111349D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Canestaro, MJ: AUTHOR

Abstract

Multiple circuit lines can be run through a via hole by using an in situ parallel lead bending process.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Fabrication of Multi-Channel through Holes without Copper Plating

      Multiple circuit lines can be run through a via hole by using
an in situ parallel lead bending process.

      A circuit board is drilled in registration.  The drilled board
is then coated with a thin layer of adhesive.  The board is laminated
on both sides with copper foil that bridges over the via holes.  The
desired circuit line pattern is exposed, developed, etched and
stripped using photo lithography techniques, leaving cantilevered
lines over the holes.  An elastomeric material is placed on the top
side of the circuit board and a hard (non-compliant) plannishing
plate is then placed in a hydraulic press, for a short period of time
under enough pressure to cause the elastomer to bulge into the hole,
bending the leads downward and against the hole wall.  The procedure
is reversed for the bottom leads.  The leads can overlap each other
without harm.  The circuit board is then dipped in solder to insure
top to bottom continuity, and is solder leveled, if necessary.