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Electrophoretic Polymer Deposition Fix of Glass Dam Porosity and Quality Check on Glass Porosity

IP.com Disclosure Number: IPCOM000081575D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Herel, EH: AUTHOR [+3]

Abstract

Glass dams serve to prevent solder removal at the chip joint during the solder reflow operation, due to surface tension effects of the molten solder. Production of the glass dams on a metallized substrate consists of silk-screening fritted glass onto silver-palladium alloy lines of the ceramic substrate at certain places, firing the substrate in order to sinter the glass, then 10/90 SN/Pb plating on the (nonglass covered) silver-palladium lines. Porosity of the glass dams is undesirable.

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Electrophoretic Polymer Deposition Fix of Glass Dam Porosity and Quality Check on Glass Porosity

Glass dams serve to prevent solder removal at the chip joint during the solder reflow operation, due to surface tension effects of the molten solder. Production of the glass dams on a metallized substrate consists of silk-screening fritted glass onto silver-palladium alloy lines of the ceramic substrate at certain places, firing the substrate in order to sinter the glass, then 10/90 SN/Pb plating on the (nonglass covered) silver-palladium lines. Porosity of the glass dams is undesirable.

Electrophoretic polymer deposition (EpD) can be used, by taking advantage of the fact that the EPD process seeks out conductive paths of a porous dielectric (covering a conductor) and allows filling and plugging of the pores via polymer electrodeposition.

A suitable dispersion must be used having the proper wetting characteristic, proper polymer composition and sufficiently small particle size of the colloid particles to enter and fill a capillary void. This method can also be used as a quality check of the porosity or lack of porosity of glass dams.

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