Study on the factors influencing warpage of FPC for LCM

The single-sided FPC for LCM (Liquid Crystal display Module) is one of the important products of FPC. Since it belongs to the parts of LCM, its warpage problem will have a significant impact on its assembly, thus affecting the quality of the product. In this paper, we focus on the parameters of lamination, the variation angle of the substrate, and the reinforced structure of the substrate to study the methods to reduce warpage of FPC and increase its passing rate. The result shows that the necessary lamination process significantly reduces the qualification rate, the angle of the substrate is an effective way to improve the qualified rate, the qualified rate increases with the increase of the angle, and the qualified rate can reach 78.7% when the angle of the substrate reaches 90°. The reinforced mode is also an important influencing factor, and the qualified rate can reach 90.5% in mode (b). Combining the three factors, the qualified rate of single-sided FPC can be significantly increased from 0% to 95.8%, and the study has high reference value for other single-sided PFC fabrication processes.