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Browse Prior Art Database

Selective Component Protector for Card Assembly Solder Process

IP.com Disclosure Number: IPCOM000112394D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Best, D: AUTHOR [+5]

Abstract

This disclosure describes the unique tooling and process method which was developed to solve several manufacturing problems associated with manufacturing hybrid assemblies with backside components and topside PIH components.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 78% of the total text.

Selective Component Protector for Card Assembly Solder Process

      This disclosure describes the unique tooling and process method
which was developed to solve several manufacturing problems
associated with manufacturing hybrid assemblies with backside
components and topside PIH components.

      Unique module fixturing which enables us to run card assemblies
through the wave solder process with modules on card assembly
backsides was developed.  This fixturing consists of a module cap
fabricated out of .010" titanium sheet.  This material was selected
since the solder does not wet and attach to titanium.  The cap was
designed to allow for a press fit onto the backside components.  The
cap will effectively completely seal the component when it is
submerged in the PIH solder wave.  When the assemblies exit the wave
solder, the caps are removed and the assembly continues through the
cleaning process.

      The material chosen meets three criteria.  First, the material
withstands the thermal stress of the solder wave such that it will
not expand and therefore fall off the component.  Second, it provides
some heat sink capability such that the module solder joints do not
approach eutectic solder reflow temperatures.  Finally, solder does
not wet to the cap material.

      Solder defects associated with this process are running 1.5 ppm
based on 1.325 million solder ball opportunities for error, giving
high confidence levels for this process, and also...