Deep and Vertical Polyimide Etching

Polyimide (PI) has been used widely in electronic device manufacture process, such as micro-electro-mechanical systems (MEMS) device and advanced packaging. Due to the limitation of the manufacture process, in general, patterned PI with depth of less than 10 μm is usually adopted in these applications. In this work, a cyclic deposition/etch method is demonstrated, and the patterned PI with depth of more than 30 μm and nearly vertical profile is obtained. Furthermore, the carbonization of PI is avoided by controlling the forward source/bias power and temperature during the etch process. The etch method and structure may be useful in the research and development of some new devices.