불화탄소계 플라즈마 식각 공정의 글로벌 플라즈마 반응기와 표면 반응 모델의 연관성 영향 연구

다국어 초록 (Multilingual Abstract)

Recently, one of the critical issues in the etching processes of next generation semiconductor devices is to achieve the ideal ultra-high aspect ratio (UHAR) deep contact hole etch profile. To address this issue, fluorocarbon plasma with various additive gases has been used to deposit fluorocarbon film which protects the sidewalls of the etched SiO2 nanostructure during the anisotropic etch process of UHAR. However, this plasma etching process has been well known as a research area of which scientific understanding is impossible due to their inherent complexities in spite of long research history. Therefore, the semiconductor industries still suffer from absence of the predictable modeling research works and depend on their empirical development approach, leading to high cost and long development periods. It is well known that the bulk plasma behavior can be strongly affected by the surface reactions at the boundaries of plasma reactors such as walls and wafers. In spite of it, there has been no research work to investigate this effect due to their inherent complexity. In this work, the bulk plasma model, which consists of electron heating model and transport module of each species and developed in national fusion research institute, was considered with gas-phase chemistry in fluorocarbon plasma. The gas-phase reaction set and reaction coefficients are assembled based on literature and experimental measurements in the plasma consortium. On the other hand, the surface reaction chemistries with the assumption of Langmuir isotherm were used for investigation of coupling effects with the bulk plasma model in fluorocarbon plasmas. The coupling algorithm was that the surface reaction modeling accepts reactive fluxes to the surface from the plasma, generates the surface coverage of species by implementing a modified site-balance, and calculates the etch yield. And, the surface modeling describes the interaction of the produced species by gas-phase with reactor walls. Finally, the coupled model is not only takes into account the effect of surface reactions on plasma properties(species densities, etc.) in the gas-phase, but also allows the calculation of fluxes of byproduct species that outputs from surface to gas-phase. The plasma electronic and physicochemical results of the coupled model are compared with experimental data with the variation of plasma process conditions.

목차 (Table of Contents)

• 제 1장 서론 1
• 제 2장 이론적 배경 4
• 2.1 불화탄소계 플라즈마를 이용한 실리콘 산화막 식각 공정 4
• 2.2 플라즈마 반응기 모델 7
• 2.3 플라즈마 표면 반응 모델 13
• 2.4 플라즈마 반응기 및 표면 반응 연관성 선행 연구 결과 16
• 2.5 연구 동기 및 독창성 21
• 제 3장 이 론 23
• 3.1. 플라즈마 반응기 모델 23
• 3.1.1 전자 가열 모델 26
• 3.1.2 공간 평균 유체 모델 28
• 3.1.3 고주파 쉬스 모델 31
• 3.2 플라즈마 표면 반응 모델 34
• 3.3 플라즈마 반응기 및 표면 반응 데이터 베이스 37
• 3.4 플라즈마 반응기와 표면 반응 연동 모델 40
• 제 4장 결과 및 토의 43
• 4.1 플라즈마 반응기 및 표면 반응 연동에 따른 플라즈마 전기적 특성 변화 47
• 4.2 플라즈마 반응기 및 표면 반응 연동에 따른 플라즈마 물리화학적 특성 55
• 4.3 식각 특성 61
• 제 5장 결론 64
• 참고 문헌 65