Post on 16-Oct-2021
From Fundamental to Application: One Universal Solution Toward Highly Efficient PCMP Ceria Cleaning in
Advanced FEOL Processing
Inspection Methods
Fundamental
Introduction
Jhih-Fong Lin*, Paul Bernatis, Pei-Yu Tai, Chia-Hui Bai, Eric Lee, Wen-Hsuan Chang, Ling Chang, Akira Kuroda and Chi Yen
EKC Technology, DuPont
EKC DuPont RESTRICTED
Results and Discussion
Conclusions or Future Application
With the semiconductor manufacturing pitches advance node, ceria based slurrieshave been widely applied to achieve rapid removal rates of silicon oxide (TEOS) infront-end-of-line (FEOL) chemical mechanical planarization (CMP) processing. Inaddition to the relatively strong chemical bond with the oxide surface, oppositecharge and tiny size of ceria abrasive makes ceria post-CMP cleaning a greaterchallenge than before. As a result, formulating chemistry starts to emerge inmarket and gradually replaces commodity chemistry such as diluted HF(dHF),ammonia SPM and SC1, in both logics and memory applications.
POR EKC-CE150 EKC-CE072
Defectivity (≥0.07μm )
TEOS SiN
0%
50%
100%
2.00 4.00 6.00 8.00 10.00
pH
Chelator A Chelator B Chelator C Chelator D Chelator G
195 143
784
417
0
500
1000
Chelator A Chelator B
Defectivity (≥ 0.07μm) of cleaned dielectric surface by
formulation with different chelator
TEOS SiN
2
4
6
8
10
12
0.00 5.00 10.00 15.00 20.00
pH
ml KOH (0.042M)
HNO3 2 mmole Ce3+ 4 mmole Ce3+
6.8
(a)
(b)
(c)
Figure 3. (a) Complexation behavior of Ce3+ versus varying chelators cross pH 2-10;(b) hydrolysis of Ce3+, which explains the dropping of complexation yield for some chelators at pH above 7; (c) impact of chelation agent switching in cleaning performance, in which the POU of formulation is acidic.
94.16
42.99
94.12
0
50
100
150
POR EKC-CE150 EKC-CE245
Degree of abrasive dispersion
0.06 0.01
0.78
0%
20%
40%
60%
80%
100%
POR EKC-CE150 EKC-CE245
Passivation yield between abrasive and SiN
Figure 4. (a) Dispersion and (b) passivation capability of formulation. (c) Cleaning performance of corresponding formulation on SiN surface in practice.
(a)
(b)
(c)
Formulation Optimization Component Screening
POR EKC-CE150 EKC-CE245
Tota
l Def
ect
Co
un
t
SiN defectivity (≥ 0.07μm)
(a)
(b)
Figure 1. (a) Ceria CMP Processing and (b) cleaning performance of EKC-CE150, as well as EKC-CE072 versus POR
(a)
(b)
Figure 2. (a) Titration-based technique as the chelator screening methodology and (b) methodology for abrasive-dielectric passivation inspection.
http://gruppotpp.unisa.it/en/chelating-agents-to-treat-the-iron-chlorosis-definition-and-mechanism-of-action/
Abrasive redeposition
Clean dielectric coupon
1
2.24
0.61 0.63
1
0.01
0.52
0.020
0.5
1
1.5
2
2.5
POR EKC-CE072 EKC-CE150 EKC-CE245
Normalized defectivity (≥0.07μm ) on cleaned dielectrics
TEOS SiN
• Voltammetric titration method and filtration-basedmethodology provides more significant insight forPCMP processing such as the working window ofcleaner formulation and abrasive behavior informulating chemistry
• The ceria cleaner solution EKC-CE245 is developedby synergizing strength of EKC-CE072 as well asEKC-CE150.
• Compared to commercial POR, EKC-CE245 canachieive 37% and 98% reduction in defectivity onTEOS and SiN surface, respectively.
Two templates EKC-CE072 and EKC-CE150 have been developed and demonstrates their capability on SiN and TEOS cleaning, respectively. Considering to replace commodity chemistry such as SC1 as well as acidic POR in customer side. One universal solution toward varying cleaning issue is urgently needed.
Com
ple
xation y
ield
Passivation%= [𝐶𝑒]𝑟𝑒𝑚𝑎𝑖𝑛𝑒𝑑 𝑜𝑛 𝑠𝑢𝑟𝑓𝑎𝑐𝑒
[𝐶𝑒] 𝑡𝑜𝑡𝑎𝑙
jhih-fong.lin@dupont.com