We have developed a novel self-alignment process using the surface tension of the liquid resin for assembly of electronic and optoelectronic devices. Due to their characteristics of low surface tension, however, the parametric design guidelines are necessary for resin self-alignment capability. In this paper, a shape prediction mathematical model and a numerical method are developed. The developed system is capable of achieving the liquid joint geometry and the parametric design for self-alignment capability. The influences of geometric parameters such as liquid volume, component weight, pad radius, liquid surface tension on the shape of liquid joint are investigated. Furthermore, the parametric design guidelines considered the process-related practical matters of misalignment level, distribution of the supplied liquid volumes and coplanarity deviation includes difference of the height between the pads are provided.

A novel self-alignment process using the surface tension of the liquid resin for assembly of electronic or optoelectronic devices in 3-D space has been proposed. The vertical alignment can be controlled by using of metal sphere, reducing the necessary precise process control such as solder volumes and external forces, and allowing large tolerances in liquid volume and misalignment. Lateral alignment could be also achieved by making the liquid resin constrained on the 3-dimensional pads on chip and substrate. This study focused on the principle of self-alignment and final alignment accuracy. In addition, the possibility of self-alignment process was verified by analytic numerical method and scaled-up experiment. An average alignment accuracy of less than 0.25 µm has been obtained. It is thought that this process is effective for assembly simply at low process temperature, low cost and without flux in future assembly techniques.

We have developed a novel self-alignment process using the surface tension of the liquid resin for assembly of electronic or optoelectronic devices. Though the liquid resins have a characteristics as low as one tenth of the surface tension of solder in general, restoring forces for self-alignment capability can be produced by making it constrained on the 3-dimensional pads on chip and substrate. In this paper, its principle and characteristics are described and the relationship between process parameters and joint geometry were examined. And 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 0.4 µm. It can provide a useful information on various parameters involved in joint geometry and optimal design guideline to generate the proper profiles.