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Research Article

Study on Stability according to Triethanamine Content of CMP (Chemical Mechanical Polishing) Ceria Slurry for Semiconductors Containing Amphoteric Surfactant Dispersant

양쪽성 계면활성제 분산제가 함유된 반도체용 CMP(Chemical Mechanical Polishing) 세리아 슬러리의 트리에탄아민 함량에 따른 안정성 연구

Jiseong Ha1, Jeongweon Yang2, and Woonjung Kim3

하지성1, 양정원2, 김운중3

1Department of Cosmetic Science, University of Hannam, Doctorate course
2Department of Chemistry, University of Hannam, The master's course
3Department of Chemistry, University of Hannam, Professor
1한남대학교 코스메틱사이언스학과 박사과정
2한남대학교 화학과 석사과정
3한남대학교 화학과 교수
30 June 2024. pp. 111-121
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Abstract
CMP(chemical mechanical polishing) 공정은 공정 과정을 거치면서 웨이퍼에 생기는 패턴 단차를 화학 및 물리적 작용을 이용하여 평탄화, 불필요한 박막을 제거하는 공정이다. 양쪽성 계면활성제 구조를 가진 분산제는 CMP 공정 중 중앙 부분과 모서리 부분의 연마율에 큰 변화가 없으나 경시적으로 pH 감소가 나타나며 입자들의 응집이 발생한다.
본 연구에서는 양쪽성이온 분산제를 사용한 슬러리에 트리에탄올아민(Triethanolamine)을 단계적으로 첨가하여 안정성 연구를 진행하였다. pH, conductivity, OM(optical microscope), DLS(dynamic light scattering), viscosity, zeta potential을 이용하여 분산 안정성을 확인하였으며 트리에탄올아민을 첨가한 슬러리의 연마율을 비교 분석하였다.
본 연구 결과, pH는 약 3 정도 낮아졌으며 TEOA (triethanolamine) 첨가 함량이 높을수록 변화 폭이 작고 안정함을 확인하였다. Conductivity 분석 결과 전체적으로 상승하는 결과를 보였고, TEOA 함량이 증가할수록 더 높은 상승폭을 보였다. OM 분석 결과 실온에서는 큰 변화가 없었지만 60℃에 보관한 CMP 슬러리의 경우 입자의 응집을 확인하였으나, TEOA를 첨가한 슬러리는 온도에 관계없이 안정함을 확인했다. Zeta potential 분석 결과 CMP 슬러리에 비해 TEOA를 첨가한 슬러리는 초기와 큰 변화 없이 안정적인 분산성을 나타내었다. DLS 분석 결과 CMP 슬러리는 실온에서 약 160nm, 60℃에서 약 330nm로 입자 사이즈가 증가했지만, TEOA 첨가 슬러리는 초기와 큰 변화 없이 안정함을 확인하였다. Viscosity 분석 결과 양쪽성 계면활성제의 영향으로 안정적인 분산성을 확인하였다. 연마율의 경우 TEOA 함량이 증가함에 따라 HDP막의 연마량 감소가 확인되었다.
The chemical mechanical polishing (CMP) process is a procedure that employs chemical and physical actions to flatten the pattern steps that appear on the wafer during processing and remove unnecessary thin films. Dispersants with an amphoteric surfactant structure do not significantly alter the polishing rate of the center and edges during the CMP process, but pH decreases over time and particle agglomeration occurs.
In this study, stability studies were conducted by gradually adding triethanolamine to a slurry using a zwitterionic dispersant. Dispersion stability was confirmed using pH, conductivity, optical microscopy (OM), dynamic light scattering (DLS), viscosity, and zeta potential measurements. Additionally, the polishing rate of the slurry containing triethanolamine was compared and analyzed.
As a result of this study, it was confirmed that pH was lowered by about 1 at room temperature and approximately 3 at 60°C, Additionally, it was observed that the higher the amount of Triethanolamine (TEOA) added, the smaller the change, indicating greater stability. The conductivity analysis showed an overall increase, with a higher increase as the TEOA content increased. Optical microscopy (OM) analysis revealed no significant change at room temperature, but particle agglomeration was confirmed in the case of the CMP slurry stored at 60°C. However, the slurry with added TEOA was confirmed to be stable regardless of temperature. Zeta potential analysis indicated that, compared to the CMP slurry, the slurry containing TEOA exhibited stable dispersibility without significant change from the initial state. Dynamic light scattering (DLS) analysis confirmed that the particle size of the CMP slurry increased to about 160 nm at room temperature and approximately 330 nm at 60°C, while the TEOA-added slurry remained stable with no significant change from the initial state. Viscosity analysis showed stable dispersibility due to the influence of the amphoteric surfactant. In terms of the polishing rate, it was confirmed that the polishing amount of the high-density plasma (HDP) film decreased as the TEOA content increased.
Keywords
CMP(Chemical Mechanical Polishing)
Ceria slurry
Triethanolamine
Amphoteric surfactant
Dispersant
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Information
  • Publisher :The Society of Convergence Knowledge
  • Publisher(Ko) :융복합지식학회
  • Journal Title :The Society of Convergence Knowledge Transactions
  • Journal Title(Ko) :융복합지식학회논문지
  • Volume : 12
  • No :2
  • Pages :111-121
  • DOI :https://doi.org/10.22716/sckt.2024.12.2.010
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