Browse Prior Art Database

Solder Decal Design for Induction Heating Reflow

IP.com Disclosure Number: IPCOM000113458D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Imken, RL: AUTHOR

Abstract

Disclosed is a means of reflowing solder decals by induction heating and constructing solder decals in a manner which provides for more efficient reflow.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Solder Decal Design for Induction Heating Reflow

      Disclosed is a means of reflowing solder decals by induction
heating and constructing solder decals in a manner which provides for
more efficient reflow.

      Solder decals have been shown to be an effective means of
applying controlled amounts of eutectic solder to electronic circuit
carriers for applications with fine-pitch component attachment such
as Direct Chip Attach (DCA), Surface Mount Array (SMA), or Tape
Automated Bonding (TAB) (1,2)  A solder decal is produced by
electroplating a tin/lead composition through a photoresist onto a
substrate which is electrically conductive.  The substrate is chosen
from a group of materials such as aluminum, stainless steel, or
titanium which are not wetted by the solder when it is reflowed with
heat.  This allows the solder to transfer to an electronic circuit
carrier on which it has been placed.

      Typically, the site on the circuit carrier which is to receive
the transfered solder is coated with an appropriate flux, and the
decal is precisely placed in position.  The application of heat to
reflow solder on decals is achieved by passing the electronic circuit
carrier through a infrared furnace.  This results in the heating of
the entire carrier, damaging protective coatings such as Entek which
prevent oxidation of the copper.  If other components are on the
circuit carrier at this point, they also are exposed damaging heat
and reflow of any existing solder joints.  In addition, vibration and
acceleration experienced in transporting the circuit carrier to and
through the belt-driven reflow furnace can cause misalignment of the
decal to the appropriate site on the carrier, resulting in incomplete
or erroneous solder transfer.

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