Etching of Si-based materials using fluorocarbon plasmas : Etch characteristics and its applications
- 주제(키워드) plasma etch , fluorocarbon plasma , Si-based material , etching ,
- 발행기관 아주대학교
- 지도교수 김창구
- 발행년도 2019
- 학위수여년월 2019. 2
- 학위명 박사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000028424
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
In this thesis, Si-based materials were etched in various fluorocarbon plasmas, and the etch characteristics in plasma were investigated using PFCs and alternative compounds as a PFC replacement. The etch characteristics of each plasma were analyzed based on the angular dependence of the etch rates using a Faraday cage, which can be used to control the ion-incident angles. Fluorocarbon plasma was used in various applications by fabricating a superhydrophobic surface. The subjects of this thesis can be grouped into the following three categories. (1) SiO2 and Si3N4 were etched, and the etch characteristics were analyzed, in various PFC plasmas. Based on the angular dependence of SiO2 etch rates with bias voltages in CF4, C2F6, and C4F8 plasmas, the relationship between the etch yield and steady-state fluorocarbon film was studied. The etch yield of Si3N4 was observed based on angular dependence of etch rates at various flow rates of CH2F2 in C4F6/CH2F2/O2/Ar plasmas. (2) To replace PFC with a lower-GWP etchant, heptafluoropropyl methyl ether (HFE-347mcc3) and perfluoropropyl vinyl ether (PPVE), which are substances in hydrofluoroether and perfluoroalkyl-vinyl-ether, were used as fluorocarbon plasma precursors to etch SiO2. The etch rates of the SiO2 at various ion-incident angles in HFE-347mcc3/Ar and C4F8/Ar plasmas were compared with each other, and the etch mechanisms were identified based on the change in etch yields. PPVE/Ar plasma was compared with HFE-347mcc3/Ar plasma with regard to the SiO2 etch rate as a function of the bias voltage, and the characteristics of the steady-state fluorocarbon film formed on the SiO2 in both plasmas were investigated. (3) The fabrication of a superhydrophobic Si surface was achieved using a cyclic etch process consisting of alternating deposition and etch steps in fluorocarbon plasma. The wetting behavior of the microscale rods on theSi surface was explained through a combination of the Wenzel and Cassie-Baxter models. A superhydrophobic Si surface with a contact angle of 165° was successfully achieved through a combination of microscale rod structures and the deposition of a fluorocarbon film.
more목차
Abstract i
List of Tables vi
List of Figures vii
Chapter 1. Introduction 1
1.1 Plasma etching 1
1.2 Phenomena in fluorocarbon plasmas 5
1.3 Objective 11
Chapter 2. Etch characteristics of Si-based materials in perfluorocompound and alternative compound plasmas 12
2.1 Introduction 12
2.1.1 Plasma etching of SiO2 and Si3N4 12
2.1.2 Fluorocarbons in SiO2 and Si3N4 plasma etching: Perfluorocompounds (PFCs) 18
2.1.3 Fluorocarbons in SiO2 and Si3N4 plasma etching: Alternative compounds 22
2.2 Experimental 24
2.2.1 Inductively coupled plasma etcher system 24
2.2.2 Faraday cage system 24
2.2.3 Evaluation of etching 27
2.3 Etch Characteristics of Si-based materials in PFC plasmas 29
2.3.1 SiO2 etching in CF4, C2F6, and C4F8 plasmas 29
2.3.2 Si3N4 etching in C4F6/CH2F2/O2/Ar plasmas 46
2.4 Etch characteristics of Si-based materials in alternative compound plasmas 63
2.4.1 SiO2 etching in hydrofluoroether plasmas 63
2.4.2 Comparison of SiO2 etching in hydrofluoroether and perfluoroalkyl vinyl ether plasmas 81
2.5 Summary 94
Chapter 3. Fabrication of superhydrophobic surfaces using fluorocarbon plasmas 101
3.1 Introduction 101
3.2 Experimental 104
3.2.1 Fabrication of microscale rod structures of Si 104
3.2.2 Deposition of fluorocarbon films 107
3.2.3 Measurement of the contact angle 109
3.3 Results and discussion 110
3.4 Summary 120
Chapter 4. Conclusions 122
Bibliography 128
Abstract (국문초록) 142
