Self-alignment of microparts using liquid surface tension - behavior of micropart and alignment characteristics

The purpose of this research is to establish a self-alignment technique for microparts assembly using liquid surface tension. The factors that influence alignment performance are examined and ways of performance improvement are discussed experimentally and theoretically. First, the relationship between the alignment accuracy and the behavior of the micropart and the water droplet is examined in the alignments with six different water droplet volumes. The experimental results show that the volume influences the alignment accuracy and the behavior. Next, the relationship between restoring force induced theoretically and the experimental alignment accuracy is discussed. Then, the effect of pattern change of the boundary between different wettability areas on the alignment accuracy is examined experimentally. In the experiments, the micropart with the hexagonal boundary pattern demonstrates smaller alignment error than those with the square, triangular, cross and star patterns. (C) 2002 Elsevier Science Inc. All rights reserved.