Browse Prior Art Database

Backside Surface Treatment for Corrosion/Oxidation Protection

IP.com Disclosure Number: IPCOM000103404D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Bonnell, RE: AUTHOR [+2]

Abstract

Disclosed is a process for protecting the backside of electronic circuit cards from oxidation during infrared soldering of topside components. The disclosed process involves the coating of the back side of the circuit card, after topside component placement and prior to infrared reflow, with a flux compatible with the cleaning system used for the cleaning of the topside flux system.

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Backside Surface Treatment for Corrosion/Oxidation Protection

      Disclosed is a process for protecting the backside of
electronic circuit cards from oxidation during infrared soldering of
topside components.  The disclosed process involves the coating of
the back side of the circuit card, after topside component placement
and prior to infrared reflow, with a flux compatible with the
cleaning system used for the cleaning of the topside flux system.

      Flux applicator would be a standard foam fluxing system similar
to those used in a wave soldering operation.  The flux is applied
immediately prior to the circuit card entering the infrared reflow
oven.  This coating provides an oxidation barrier limiting the rate
of oxygen transport to the exposed copper surfaces and for the
removal of any oxides present or formed during the infrared process.

      After exiting the infrared oven the backside flux would be
removed during the topside post reflow cleaning operation.

      Electronic testing of circuit cards would be facilitated by
limiting the corrosion formed at test via locations, therefore,
increasing the reliability of this operation, oxidation of exposed
copper surfaces will be lessened prior to subsequent backside
component attachment operations and faster throughput/ higher
temperature infrared profiles could be utilized due to a lowered
oxidation rate provided by the fluxing operation.

      Disclosed anonymously.