The effects of surfactants on the electroless nickel plating process and coating’s mechanical properties in the blind hole metallization of PCB

• Main Authors: Chen-Hsin Yao, 姚承鑫
• Other Authors: Chun-Ying Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/qjrsty

碩士 === 國立臺北科技大學 === 製造科技研究所 === 104 === Printed circuit board (PCB) with multi-layered circuit configuration has become an important technical practice in applications. The via between circuit layers play a key component role for the integration of the circuits. For further compaction of the circuit layers, the blind via hole would be an indispensible technique and deserve continuous breakthrough. During electroless nickel plating in blind hole, the blocked path renders the flow of electrolyte difficult inside the cavity. Hence, the replenishment of reaction reagents will be difficult without the bulk flow of electrolyte. The successful plating inside the blind via hole can be challenging. In this thesis, different types of surfactant were employed to reduce the surface tension of the electrolyte and improve its wetting inside the blind hole. Among the surfactants used in this study, the anionic surfactant SDS demonstrated the best improvement in blind hole plating while the cationic surfactant CTAB caused the interruption of plating even in planar substrate. With the addition of 4 g/L SDS in the electrolyte, the hardness of the coating increased by 60% comparing with its pristine counterpart. From the composition measurement of EPMA, no significant modification in alloying element content was observed. This hardness increase should be indebted to the presence of Ni3P in the coating associated with the reduction of Ni upon the addition of SDS in the electrolyte. The results of different surfactants and the amount of supercritical carbon dioxide by mixing after electroless plating solution, the addition of SDS part, related to the general trend shown by electroless plating solution exhibited the trend is similar, but in addition of PEG part, because the non-ionic surfactant helps the carbon dioxide gas into an electroless plating solution, so the PEG portion will have a good result. In the plated blind hole depth analysis as part of the analysis of SDS optimal depth plating, add has three different sizes of blind holes can be close to 100% of the analysis of SDS 4g / L plating depth. Compared with the general electroless plating, the blind hole depth analysis plated blind holes after super critical process of better performance, because when the supercritical carbon dioxide has been mixed while plating bath having properties of gases and liquids, this feature will reduce the surface tension of the bath, in the atmospheric vent to the effect will still exist in some time, after blind hole supercritical process of analyzing plating depth will come no better than the average plating material.