Development of a three-dimensional integrated solder ball bumping & bonding method for MEMS devices

Compared with integrated circuits, MEMS devices are more sophisticated and diverse. The complex non-planar micro components of MEMS devices raise the urgent needs for three-dimensional (3-D) packaging. To fulfill the specific needs in 3-D MEMS packaging, the basic concepts of a new 3-D integrated solder ball bumping & bonding method for MEMS devices was proposed. A prototype platform was developed according to the concepts with pads detection, micro solder ball manipulation, fluxless laser reflowing and bumps repairing processes. In the prototype platform, an improved center detection algorithm with the combination of the randomized Hough transform and the least squares method was integrated. The detecting tests indicated that the precision of the detecting algorithm can reach 0.21μm, and its computing time was less than 10ms. With further experiments verification, solder bumping and microsensors packaging experiments were carried out.