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Browse Prior Art Database

Repair Process for Ball Grid Arrays

IP.com Disclosure Number: IPCOM000117900D
Original Publication Date: 1996-Jul-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Boyd, A: AUTHOR [+4]

Abstract

The repair of assemblies using Ball Grid Array (BGA) component technology often results in short and open circuits which are difficult to detect during the repair process. The improved process described below enables inspection of the new solder at the repair site prior to fitting a new component.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Repair Process for Ball Grid Arrays

      The repair of assemblies using Ball Grid Array (BGA) component
technology often results in short and open circuits which are
difficult to detect during the repair process.  The improved process
described below enables inspection of the new solder at the repair
site prior to fitting a new component.

      In the new process, heat is applied locally to the underside of
the card (under the BGA site) as well as the topside over the BGA
component, using a split optics fine placer repair tool.  The arm of
the fine placer lifts the CBGA component clear of the card when
sufficient heat has been applied to melt the solder joints.  At this
stage some of the balls remain on the card while some remain attached
to the component.

      The site is cleared of all solder using a hot gas desoldering
tool.  Inert gas at 700f melts the eutectic solder and the
desoldering tool pulses vacuum to suck away the molten solder and
lead balls from the site.  Solder paste is then screen printed on to
the site with a special stencil.  Covered recesses may be provided in
the stencil so that screen printing is still possible even if there
are components in close proximity to the BGA.  The recesses fit over
the components.  A fixture ensures that the stencil aligns with the
BGA site.

      The paste is then reflowed with hot inert gas from the arm of
the fine placer.  The site is then inspected for shorts, low solder,
and then repairs a...