Further Physical Characteristics of Vacuum vs. Atmospheric Baked Polymers for FOWLP Processing

Abstract

While there are a number of different polymer cure processes, the specific process has a significant effect on the quality and performance of cured polymers, applicable to FOWLP Multi-level Metallization Process. The measurement for variations of noise immunity, dielectric strength and other dielectric properties in the most common baked polymers used for FOWLP manufacturing are still a huge challenge in the back-end industry. In this paper, the measurement of cured-film composition and dielectric properties were studied for different types of Polyimide and PBO materials as a function of different cure process parameters. Comparisons of the amount of outgassing at metallization under different process conditions supported the theory of vacuum bake as a more complete cure process. The paper reports the comparison of trapped gases, as well as amount of outgassing, as a function of levels of vacuum bake, time and temperature of the bake. The films cured under different conditions were studied using different characterization methods such as FTIR, RGA, etc. In conclusion, the importance of the cure process is presented with respect to multi-level metallization, low noise immunity and low to zero outgassing for current FOWLP.