Effects of Imidization Process on the Electric Breakdown Strength of Polyimide Thin Film

Abstract:

The electric breakdown voltage (V_bd) is a fundamental performance index for insulation thin film in MEMS, and plays a dominant role for the operation reliability of this kind of devices. In this work, positive polyimide (PI) photoresist was used to prepare thin films by spin-coating and thermal imidization. Electric breakdown experiments were carried out under DC voltage mode. The effect of imidization temperature on V_bd was also studied by setting three different imidization temperature profiles. XRD was applied to test the composition and microstructure of the PI thin films. Results show that the imidization degree of the PI thin film will be increased with the raising of the imidization temperature from 280 to 350°C. This means that a more completed imidization process can be achieved in the PI thin film by using higher imidization temperature. The highest V_bd of about 2740V and an average V_bd of 343kV/mm can be achieved on a 8.5μm thick PI thin film imidized at 350°C.

• Periodical: Applied Mechanics and Materials (Volume 868)
• Pages: 248-253
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.868.248
• Online since: July 2017
• Authors: Jun Sheng Liang*, Xu Fang, Jin He Yang, Tong Qun Ren, Da Zhi Wang
• Keywords: Electric Breakdown, Polyimide Thin Film, Spinning-Coating, Thermal Imidization

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