A comparison of BCB with Polyimide process in manufacturing HBT devices

This paper reports on the development of BCB (Bisbenzocyclotene) process at Skyworks Solutions Incorporation - Sunnyvale facility. In this study, we have obtained very promising results demonstrating that the BCB process can readily replace the PI (Polyimide) process without significantly changing process design or reliability. Our study indicates that too much SF6 will slow down the etch rate of the BCB, while higher chamber pressure will increase the etch rate and uniformity across the wafer. We also able to control the BCB profile by using different RF power levels. Proper adjustment in chamber pressure and RF power setting optimized our BCB process resulting in a very repeatable etch rate uniform and design profile.