Void formation on PCB surface finish during reflow soldering

Author

Ewald, Thomas D. ; Holle, Norbert ; Wolter, Klaus Jürgen

Author_Institution

Eng. Assembly & Interconnect Technol., Robert Bosch GmbH, Stuttgart, Germany

fYear

2011

fDate

11-15 May 2011

Firstpage

153

Lastpage

161

Abstract

Printed circuit board (PCB) surface finish and its reactive wetting process were identified as a main cause of voiding. During reflow soldering liquid flux residues adhered to the interface PCB / liquid solder alloy form voids while the solder alloy is in a liquid state. In contrast to that no voids are found when no reactive wetting occurred. Furthermore, we observed that the number of detected voids after the reflow process strongly depends on the tin layer thickness: Many voids are formed in the case of a thin tin layer, no voids are found in the case of a very thick tin layer. A model is established to explain this phenomenon.

Keywords

adhesion; metallic thin films; printed circuits; reflow soldering; surface finishing; tin; voids (solid); wetting; PCB interface; PCB surface; Sn; liquid solder alloy; printed circuit board surface finish; reactive wetting process; reflow soldering; reflow soldering liquid flux residue; tin layer thickness; void detection; void formation; Glass; Metals; Reflow soldering; Substrates; Surface finishing;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics Technology (ISSE), 2011 34th International Spring Seminar on

Conference_Location

Tratanska Lomnica

ISSN

2161-2528

Print_ISBN

978-1-4577-2111-3

Type

conf

DOI

10.1109/ISSE.2011.6053569

Filename

6053569