Abstract
IC-Quartz watches have been manufactured since the appearance of CMOS-LSI about seven years ago. Nowadays, the outside view of the quartz watch is the same as that of a mechanical watch through minimizing electronic parts such as battery, crystal oscillator, capacitor, and IC packaging volume. Recently, IC packaging technology for electronic wrist watches (both the analog quartz watch and digital quartz watch) has made a step foward. In Japan, some watch makers adopt a film carrier assembly technique for producing thin and low-priced watches. They are using 3 layers and 35 mm wide film which fits very well the substrate of the quartz watch, especially the digital quartz watch.The Citizen Watch Co., Ltd. started an investigation as to which method was suitable for IC package for watches in 1975 and adopted a flip chip technique as being the most suitable for analog quartz watches. The flip chip technique will allow the fabrication of a very small and thin package. Important characteristics of the technique permit design flexibility and high density packaging of the ICs. In this paper, a flip chip technique using a Printed Circuit Board as a substrate is described.