Investigation of the effect of nitrogen and air atmospheres on solder wettability of plasma‐treated HASL finish PCBs

Abstract

Purpose

The purpose of this paper is to evaluate the effect of nitrogen and air atmospheres on the solderability testing of plasma‐treated hot air solder level (HASL) finish printed circuit boards (PCBs).

Design/methodology/approach

In this paper, the soldering performance of plasma‐treated HASL finish PCBs in nitrogen and air atmospheres have been evaluated using the wetting balance technique. The results were compared with the performance of conventionally flux‐treated samples soldered in air and nitrogen atmospheres and non‐flux treated samples soldered in air. Auger chemical analysis results were also compared with the solderability test results in order to obtain a complete profile of the plasma‐treated and non‐treated surfaces.

Findings

The results of the auger chemical analysis show high organic (carbon) levels in the control samples and a significant drop in organic levels in the plasma‐treated samples. The significant drop in the level of carbon leads to a decrease in contact angle and an increase in both surface energy and solder wettability. The results indicate that plasma cleaning of PCBs prior to soldering is a viable alternative to the conventional use of flux.

Originality/value

The paper indicates that the soldering performance of plasma‐treated PCBs in air and nitrogen atmosphere are comparable. The findings give the motivation for the use of plasma‐assisted dry cleaning for fluxless soldering.

Citation

Takyi, G. and Ekere, N.N. (2010), "Investigation of the effect of nitrogen and air atmospheres on solder wettability of plasma‐treated HASL finish PCBs", Soldering & Surface Mount Technology, Vol. 22 No. 3, pp. 17-21. https://doi.org/10.1108/09540911011054154