Atomic Layer Deposition (ALD) Atomic Layer Deposition (ALD)
Department of Electronic Engineering
Department of Electronic Engineering , Graduate School, , Graduate School, Kyungpook
Kyungpook National University National University
Contents Contents Contents
1. What is ALD (atomic layer deposition)?
1. What is ALD (atomic layer deposition)?
2. Why use ALD (atomic layer deposition)?
2. Why use ALD (atomic layer deposition)?
3. Application by ALD
3. Application by ALD
What is ALD?
What is ALD?
What is ALD?
1. 증착하고자 하는 박막의 성분을 함유한 금속 유기물 또는 무기물을 온도와 압력하에 박막 형성과정
2. 주입/배기의 순차적인(sequential) 반복에 의해 웨이퍼 표면 위에 한 층 또는 그 이상의 박막 형성과정
3. Saturation mechanism에 의한 박막 형성과정
ALD는 saturated surface reaction(포화 표면 반응)의 박막 성장 기구를 이용하여, 반응을 일으키며 Cycle 횟수에 의해서 Thin film의 두께를 원자 층(Atomic Layer) 단위로 제어, 성장 시키는 방법
What is ALD? (process) What is ALD?
What is ALD? (process) (process)
A source Reaction gas
Chemical reactions between B source andA source & self-limiting mechanism
Reaction gas supply
1 Cycle
A source Purge Reaction gas
A source
A source supply
Chemisorption of a source and self-limiting mechanism
Purge gas supply
Purge gas supply
Pinhole free films Wide process window
Gas phase reaction eliminated Excellent step coverage
(Conformal coating)
Thickness is controlled the # of reaction step Uniformity ensured
Why use ALD ?
Why use ALD ? ( ( ALD process feature) ALD process feature)
Why use ALD ?
Why use ALD ? ( ( comparison) comparison)
Criteria
Criteria ALDALD
Atomic layer deposition
CVDCVD
Chemical vapour deposition
PVDPVD
Physical vapour deposition
Thickness Thickness
control control
Easy(1ML/cycle)
(<10Å) Difficult (~10Å) Easy(~20Å)
Uniformity
Uniformity Å range 10Årange 50Å range
Film quality Film quality
Excellent low pinhole count stress control possible
Good low pinhole count stress control possible
Limited high pinhole count limited stress
control possible
Conformity
Conformity 100% step coverage in 60:1 AR
100% step coverage in 10:1 AR, but also coverage not assured
50% step coverage in 10:1 AR
Cleanliness
Cleanliness No particle due to surface reactions
Particles due to gas phase reactions
Particles due to sputtering
ALD Process Application ALD Process Application
대구경 실리콘 집적회로 제조 공정 대면적 평판 표시소자 공정에의 응용 유전체, 절연체의 성장
금속배선공정에서의 확산방지막 (TiN, TaN, WN, TiSiN 등) 거의 완벽한 단차 피복성을 필요로 하는 반도체 공정
게이트 유전막 성장
z Oxides :
z Al2O3, ZrO2, HfO2, Ta2O5, SnO2, RuO2, SiO2
z Nitrides :
z TiN, NbN, TaN, Ta3N5, MoN, WN, TiSiN, SiN
z Elements :
z Ge, Cu, Mo, W, Ta, Ru
z Semiconductors :
z GaAs, InAs, InP, GaP, InGaP
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