Summary: | 碩士 === 聖約翰技術學院 === 自動化及機電整合研究所 === 93 === This study uses nanoindentation to measure the mechanical properties of photoresist thin films associated with a indentation simulation by way of the finite element method. The SU8 photoresist is coated on the silicon wafer with various spin coating speed. The mechanical properties of the thin films are determined by several testing methods including nanoindentation, lateral force test, substrate heating test, dynamic test, and atomic force microscope test. The results show that, as the indentation depth increases from 160nm to 380nm, the Young’s modulus increases from 9 Gpa to 19 Gpa and the hardness increase from 0.25 Gpa to 0.295 Gpa in the case of 8200 nm thickness and 25°C. Meanwhile, the mechanical properties increase as the temperature increases. In the case of 850 nm thickness and 25°C, the Young’s modulus increases from 13.5 Gpa to 26.5 Gpa and the hardness increases form 0.39 Gpa to 0.485 Gpa as the indentation depth increases from 150 nm to 308 nm, where the mechanical properties also increase with the increasing temperature. The conclusions are: (1) The hardness and Young’s modulus of the photoresist thin film increase as its thickness decrease, but decrease as its temperature increases. (2) The thickness of the photoresist has no significant effect on its friction factor. (3) The viscoelastic behavior increases as the photoresist thickness increases. Furthermore, the finite element software ANSYS is used to simulate the nanoindentation by modeling the specimen as well as the indentor and substituting the mechanical properties determined from the experiment. The numerical result of the indentation depth agrees well with the experimental data.
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