全SU8微悬臂梁的制备及其弹性系数表征

Fabrication of all-SU8 microcantilevers and its characterization of spring constant

采用Omnicoat作为牺牲层,经过两步光刻和湿法释放成功制备了全SU8结构的微悬臂梁,释放的成功率超过95%.针对SU8热膨胀系数大的缺点,对SU8微悬臂梁进行不同温度退火.采用原子力显微镜(AFM)系统对SU8微悬臂梁的弹性系数进行精确表征.结果表明,随着退火温度提高,SU8微悬臂梁弹性系数增大,对于250μm长3.5μm厚的悬臂梁,95℃退火后,其弹性系数为0.525 N·m-1;200℃退火后,其弹性系数增大到0.745 N·m-1.所制备的微悬臂梁被成功用于表征SU8与玻璃基底之间的相互作用.

We present a fabrication method of SU8 microcantilevers by incorporating phototlithography and a wet release technique using a thin omnicoat film for efficient removal at a yield of above 95%. The spring constant of fabricated SU8 microcantilevers annealed under different temperature were characterized by applying a commercial AFM system due to the thick base （around 300 gin）, which yield a more accurate measurement. It is found that the spring constant of as fabricated T - shaped SU8 microcantilevers with the total length of 250 txm and thickness of 3.5 μm was 0. 525 N · m^-1, and increased to 0. 745 N · m^-1 when the annealing temperature is 200 ℃. Furthermore, these SU8 cantilevers were demonstrated for the measurement of interactions between SUB and glass, suggesting a potential application in characterization of interface properties between two materials.