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Browse Prior Art Database

Low Temperature Redress for High Temperature Solder Columns

IP.com Disclosure Number: IPCOM000122785D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Isaacs, PD: AUTHOR

Abstract

Disclosed is an invention that is useful when there are high temperature columns and a maximum temperature limitation on the rest of the module.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Low Temperature Redress for High Temperature Solder Columns

      Disclosed is an invention that is useful when there are high
temperature columns and a maximum temperature limitation on the rest
of the module.

Low temperature process for redressing a site for recolumning:
  o  Flux bottom side of module in appropriate flux.
  o  Float or dip module in molten 63/37 tin lead solder at
      260 Degrees C for about 60 seconds, depending on the
      mass of the module.
  o  Dress bottom of module with a stainless steel blade, or
      equivalent, while the solder is still molten.
  o  Repeat above two steps, if needed, to create a cleanly
      dressed module.
  o  Allow part to cool.
  o  Clean flux, as required.

      The part is now ready for recolumning using a 63/37 solder to
join column to the bottom of the module.  This process utilizes the
diffusion of tin into the 10/90 solder joint to lower the melting
point of the column and allow it to melt into the solder.  Solder
flow can be added to increase the rate of diffusion of tin into the
higher melting solder.  Even without solder flow, the rate is
perfectly acceptable for the operation.  The temperatures involved
are acceptable  for the chip, encapsulant, cap seal and the rest of
the module.

The module is now ready for recolumning or reballing.