Browse Prior Art Database

Soldering Process for DCA Using Solder Foils or Tapes

IP.com Disclosure Number: IPCOM000107498D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Mahmoud, IS: AUTHOR

Abstract

Direct chip attach is an interconnection method which bonds the chip directly onto the circuit substrate or carrier. There are several techniques which the electronic industry has been investigating including: plating, solder jets and solder paste screening. These techniques have inherent problems or disadvantages such as lack of uniform thickness, misregistration and solder bridging in fine pitch, as is the case with DCA circuitry.

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Soldering Process for DCA Using Solder Foils or Tapes

      Direct chip attach is an interconnection method which bonds the
chip directly onto the circuit substrate or carrier. There are
several techniques which the electronic industry has been
investigating including:  plating, solder jets and solder paste
screening.  These techniques have inherent problems or disadvantages
such as lack of uniform thickness, misregistration and solder
bridging in fine pitch, as is the case with DCA circuitry.

      To resolve or minimize these problems, an alternate method is
hereby described which lends itself to both manual and automated
operations.  In both cases, a preformed, to the footprint of the
chip, solder foil is superimposed on the chip footprint.  The solder
foil is thereafter reflowed by means of a thermode designed either to
the chip footprint, for automation, or as a single point, for manual
or repair operations.  Other forms of energy could also be used to
reflow the foils including low intensity lasers, resistive heating
and others.

      Disclosed anonymously.