陳炳煇臺灣大學：機械工程學研究所鍾亞叡Chung, Ya-RuiYa-RuiChung2007-11-282018-06-282007-11-282018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/61161The purpose of this thesis is to design a novel microdevice for measuring the thermal diffusivity of a liquid droplet in small amounts. CMOS chip is fabricated by TSMC 0.35μm 2P4M CMOS process and post-CMOS micromachining processes are proceeded. The CMOS chip consists of a thin film of polysilicon that covers a cavity of the substrate. The thin film has a rectangular centered heater and four temperature sensors surrounding the heater. Once a known voltage is applied to the heater, the thermal diffusivity of liquid drop that spreads over the heater and the temperature sensors can be determined from the measured temperature responses at different locations of the temperature sensors. The thermal diffusivity of liquid drop that spreads over the heater and the temperature sensors can be determined from the measured temperature responses at an impulse voltage. The simulation and experimental results illustrate that the higher thermal diffusivity of liquid causes lower maximum temperature change. Thermal diffusivity of other liquids could be measured as well based on a relation between thermal diffusivity by measuring procedure in the thesis.Acknowledgement Ⅰ Abstract Ⅱ Nomenclature Ⅳ Table of Contents Ⅴ List of Tables Ⅷ List of Figures Ⅸ Chapter 1 Introduction 1 1.1 General remarks 1 1.1.1 Thermal diffusivity of liquids 1 1.1.2 CMOS-MEMS fabrication technology 1 1.2 Literature survey 2 1.2.1 A transient hot-wire method 2 1.2.2 A transient hot-disk method 3 1.3 Motivation and objectives 5 1.4 Thesis organization 6 Chapter 2 Finite element analysis and ANSYS simulation 8 2.1 The principle of finite element analysis 8 2.2 ANSYS simulation procedures 9 Chapter 3 Design Principle 14 3.1 CMOS 0.35 m 2P4M whole chip layout 15 3.2 Heater 16 3.3 Temperature sensors 16 3.4 Etching holes 17 3.5 Pads 17 Chapter 4 Post-CMOS Micromachining 19 4.1 Isotropic wet etching for removing metal layers 20 4.2 Anisotropic dry etching for removing silicon oxide 21 4.3 Wet TMAH etching for removing silicon substrate 23 4.4 Wire bonding 24 Chapter5 Experimental apparatus and procedures 25 5.1 Procedures of measuring thermal diffusivity of tested Liquids 25 5.1.1. Design of an impulse generator 25 5.1.2. Tested liquids specimen setup 28 5.1.3. Heat generation and temperature sensor detect 28 5.2 Experimental apparatus 28 5.3 Tested liquids 30 5.4 Relationship between resistance and temperature 31 5.5 Procedures of measuring thermal diffusivity of tested Liquids 32 Chapter 6 Results and Discussion 34 6.1 Results of ANSYS software simulation 34 6.2 Measurement temperature response by temperature sensors 35 6.3 Comparison between measured and simulated results 36 Chapter 7 Conclusions and Future Prospects 38 Reference 74en-USCMOS熱擴散係數ANSYS後製程thermal diffusivitypost-CMOS micromachiningthesis