Highly Precise Positioning Method by Pull-Up Model Self-Alignment Process Using Liquid Surface Tension
Jong-Min KIM, Kiyokazu YASUDA, Kozo FUJIMOTO, Shuji NAKATA
A novel self-alignment process was developed using liquid surface tension for future assembly of electronic or optoelectronic devices. It could be achieved for the material with low surface tension, e.g., resin materials by using 3-D pads for making the positioning boundary and mounting chips in the opposite direction for releasing the force acted on the liquid bumps. The principle and characteristics are described and the relationship between process parameters and joint geometry were examined. The possibility of self-alignment process was verified by analytic numerical method and scaled-up experiment. A self-alignment accuracy was examined experimentally and show that it became less than 0.4μm. It can provide a useful information on various parameters involved in the joint geometry and optimal design guideline to generate the proper profiles.