Browse Prior Art Database

Enhanced Wave Solder Decal Fabrication

IP.com Disclosure Number: IPCOM000117088D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Fallon, KM: AUTHOR [+3]

Abstract

The decal fabrication process used to produce 65/35 Sn/Pb decals on a stainless steel substrate has difficulty in controlling the following parameters: Sn/Pb plating thickness, plating composition, void free plating, and to provide an adequate contrast for decal placement.

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Enhanced Wave Solder Decal Fabrication

      The decal fabrication process used to produce 65/35 Sn/Pb
decals on a stainless steel substrate has difficulty in controlling
the following parameters:  Sn/Pb plating thickness, plating
composition, void free plating, and to provide an adequate contrast
for decal placement.

      Disclosed is a process for fabricating eutectic Sn/Pb decals on
an organic carrier.  Fig. 1 illustrates the decals produced through
the Enhanced Wave Solder (EWS) process.

      Fig. 2 shows the process flow for the decals.  An organic
laminate is used as the substrate.  The substrate has a resist layer
that is applied, exposed, and developed in the desired footprint
pattern.  The resist is surface treated to roughen the surface
through either vapor blast or plasma processing.  A blanket flash
copper layer is deposited on the resist.  The panel is processed
through a wave solder machine, and finally routed into decals.

      The EWS fabrication process produces decals with uniform
eutectic Sn/Pb composition.  The solder alloy may also be changed to
Sn/Bi or other alloys.

      The solder volume for the decals is controlled by the resist
opening and its thickness.

      The laminate roughness provides an adequate adhesion for the
deposited solderballs prior to transfer.  The resist will also
protect the Sn/Pb from becoming dislodged during handling.

      The resist and deposited Sn/Pb offer an improved contrast...