Development of New Formula for Filling Through-Hole by Copper Electroplating

• Main Authors: Chun-Wei Lu, 盧俊瑋
• Other Authors: Wei-Ping Dow
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/03989723978302179665

碩士 === 國立中興大學 === 化學工程學系所 === 98 === The size of electronic products is requested to be smaller and smaller. They provide several advantages such as reduced packaging area, light weight, higher interconnection density, high reliability, and excellent electrical performance with lower resistance. For traditional electroplating through hole, the throwing power of 100% have to achieve then it can meet the requirement. In recent years, many people studied the through hole electroplating. However, they need a conducting layer to be assembled at the bottom to improve the process. We consider to develop a new formula for filling through-hole by copper electroplating, and we use butterfly technology (BFT) to fill up the through hole. It can be processed at high current density, and reduce electroplating time to filling up. In general, levelers bares tetrazolium compound, electrochemical analysis can characterize the additives’ interaction in between. High current density could be applied and when multi-component formula was employed. In addition, multi-component formula can enhance the concentration gradient in the through hole. The filling performance of the multi-component formula could be enhanced with which weak and fixed forced convection combined. It could result in center-up filling mode. In sulfuric acid system, linear sweep voltammetry (LSV) and chronopotentiometry (CP) were employed to characterize these additives on copper electrode at different rotating speeds. The electrochemical analyses reveal the adsorptive ability of these additives on copper electrode. According to the electrochemical analyses, the inhibiting effect of the additive on copper deposition depends on the its concentration, that is, the higher the additive concentration, the more negative the desorption potential. This suggests that the adsorption of the additive may be multilayer or it may perform electrochemical polymerization on copper electrode. Finally, the through hole was fully filled by copper electroplating using the as-developed new formula. The hole diameter was 50 μm, the hole depth was 380 μm and the aspect ratio was 7.6. The total plating time just took 9 hours.