Browse Prior Art Database

Sequestering Gel for Site-specific Cleaning

IP.com Disclosure Number: IPCOM000121309D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Guiterrez, BL: AUTHOR [+2]

Abstract

There is disclosed a technique for removing both metal and halide ions from the card surface.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Sequestering Gel for Site-specific Cleaning

      There is disclosed a technique for removing both metal
and halide ions from the card surface.

      The technique disclosed relies on the chemical interaction
between the sequestering agents and the insoluble metal salt(s) to
produce water-soluble complex(es) which are easily washed off the
card.  Cleaning is further augmented by shrinkage of the gel during
the drying step, which acts to lift debris from the card surface.
This is analogous to the action of carpet-cleaning foams.

      An aqueous gel is applied by brushing onto a specific
component/ chip attachment site(s).  The gel contains two or more
sequestering/chelating agents. Acacia gum is used to sequester
halides; citric acid, sarcosine, EDTA, serine, or glutamic acid are
used to chelate metal ions - Sn, Pb, Cu, for example.  These
sequestering/chelating agents interact with water soluble metal
halide salts, as described above, to form water soluble complexes:
both acacia gum halide and organic acid - M+ species are water
soluble.

      The combination of chemicals used in the gel is unique in its
high water solubility, affinity for both metal and halide ions,
non-corrosive nature, and low toxicity/environmental impact.  A
further unique feature is that the acacia gum also provides a gel
structure and limits spread, so nearby components are not affected
and a site- specific process can be used.  This avoids water cleaning
the entire card, a d...