ICSR (Soldering and Reliability) Conference Proceedings

Bare Board Design Research to Improve Flux Outgassing under BTCs

Authors: Mike Bixenman, David Lober, and Mark McMeen
Company: KYZEN Corporation and STI Corporation
Date Published: 6/5/2018   Conference: ICSR (Soldering and Reliability)

Abstract: Component Specific test boards allow an assembler to study board design features at a component level, such as solder mask definition, solder mask windows, via placement, copper weights and other design options for improving standoff gaps and flux outgassing under bottom terminated components. Test boards built with specific component types allow the assembler the ability to test many process variables when qualifying soldering and cleaning processes. Testing can provide objective evidence regarding acceptable levels of flux and other residues trapped under the bottom termination.

The purpose of this paper is to research bare board design features for placement of the QFN component. The test board design has four quadrants. Design features such as solder mask definition can be different across the four quadrants. The test board has sensors placed at the pin and thermal lug regions to study the activity of flux residues and cleaning effects. The test methods will include component specific SIR followed by IC. The data findings, inferences and best practices for building reliable assemblies will be reported.

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