等离子清洗及点胶轨迹对底部填充胶流动性的影响

Effects of Plasma Cleaning and Dispensing Path on the Fluidity of Underfill Adhesive

倒装焊封装过程中,底部填充胶的流动性决定了填充效率,进而影响生产效率及成本。通过对比接触角和底部填充胶流动时间,研究了等离子清洗及点胶轨迹对底部填充胶流动性的影响。结果表明:经微波等离子清洗后,水及底部填充胶在陶瓷基板表面的浸润性均有所提高;微波等离子清洗还能促进底部填充胶在芯片和陶瓷基板之间的流动。I形点胶轨迹对应的流动时间最长,而U形点胶轨迹的流动时间最短。因此适当增加点胶轨迹的总长度,可以有效提高底部填充胶的填充效率。

During the flip-chip package process, the filling efficiency is determined by the fluidity of underfill adhesive, which further affects the production efficiency and cost. The effects of plasma cleaning and dispensing path on the fluidity of underfill adhesive were researched by comparing the contact angle and the flow time of underfill adhesive. The results show that the wettability of water and underfill adhesive on the surface of the ceramic substrate are both improved after microwave plasma cleaning. Additionally, the fluidity of underfill adhesive between the chip and ceramic substrate is better after microwave plasma cleaning. The flow time of the I-shaped dispensing path is the longest. In the contrast, the flow time of the U-shaped dispensing path is the shortest. Therefore the filling efficiency of underfill adhesive can be improved effectively by increasing the total length of dispensing path appropriately.