본 연구에서는 친환경적이고, 보관수명이 1년 이상이며, 부식특성이 좋은 플라즈마 유기막 표면처리에 대한 솔더링 특성을 기존 표면처리법인 OSP와 비교하였다. 플라즈마 표면처리는 할로겐계 전구체를 사용하여 CVD 방법으로 증착하였고, 증착두께는 20 nm이었다. 본 연구에서 사용된 솔더 조성은 Sn-3.0 wt%Ag-0.5 wt%Cu이었다. 염수분무시험에서 플라즈마 표면처리 유기막은 OSP보다 우수한 부식 저항성을 나타내었다. 멀티리플로우 조건에서 플라즈마 표면처리는 OSP보다 우수한 솔더 퍼짐성을 나타내었다. 솔더링 후 단면 미세조직을 분석한 결과, 플라즈마 표면처리와 OSP시편 모두 유사한 금속간화합물층 두께 및 형상을 갖고 있었다. 플라즈마 표면처리와 OSP 모두 유사한 접합강도를 가지고 있었다.
Plasma organic thin film for PCB surface finish is a potential replacement of the conventional PCB finishes because of environment-friendly process, high corrosion-resistance and long shelf life over 1 year. In this study, solder joint properties of the plasma organic surface finish were estimated and compared with OSP surface finish. The plasma surface finish was deposited by chemical vapor deposition from fluorine-based precursors. The thickness of the plasma organic coating was 20 nm. Sn-3.0Ag-0.5Cu (SAC305) solder was used as solder joint materials. From a salt spray test, the plasma organic coating had higher corrosion resistance than the OSP surface finish. The spreadability of SAC305 on plasma organic coating was higher than that on OSP surface finish. SEM and TEM micrographs showed that the interfacial microstructure of the plasma surface finish sample were similar to that of the OSP sample. Solder joint strength of the plasma finish sample was also similar to that of the OSP finished sample.
