1 A simulation analysis on defect annihilation in directed self-assembly lithography Katsuyoshi Kodera, Hideki Kanai, Yuriko Seino, Hironobu Sato, Yusuke Kasahara, Katsutoshi Kobayashi, Hiroshi Kubota, Naoko Kihara, Yoshiaki Kawamonzen, Shinya Minegishi, Ken Miyagi, Toshikatsu Tobana, Masayuki Shiraishi, Satoshi Nomura and Tsukasa Azuma EUVL Infrastructure Development Center A part of this work was funded by the New Energy and Industrial Technology Development Organization (NEDO) of Japan under the EIDEC project.
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A simulation analysis on defect annihilation in directed ... · A simulation analysis on defect annihilation in directed self-assembly lithography Katsuyoshi Kodera, ... (SCFT) Simulation
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3 stable/metastable morphologies including grid defect were acquired using SCFT.
most stable
quasi-hexagonal buried structures
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Stability of grid defects
𝜒𝑃𝑀𝑀𝐴−𝐵𝑇𝑀
Fre
e e
nerg
y Δ𝐹
-0.001
-0.0005
0
0.0005
0.001
0.0015
0 0.5 1 1.5 2 2.5
GD
ML
VL
Vertical lamellar state is the most stable
Mixed lamellar state is the most stable
PMMA attractive neutral
• These simulation results agree with the experimental behavior.
mixed lamellar
grid defect
vertical lamellar
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Conformation of BCP chains
(a)PMMA chain is parallel to the bottom.
(b) PMMA chain is vertical to the bottom
𝑛0~𝑛5
𝑛0 > 𝑛5, 𝑛9
terminal
center
junction
𝑛0
𝑛5
𝑛9
Neutral layer(PMMA-attractive bottom)
PMMA
We can acquire the information of the polymer chain conformation by evaluating n0, n5 and n9 immediately above the bottom.
11
Conformation of BCP chain (GD-state)
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2 2.5 3
n0 n5
n9 nPMMA
Densi
ty
Position (𝐿0) 𝑛0 > 𝑛5, 𝑛9 immediately above the bottom
𝑛0
𝑛5
𝑛9
PMMA
𝑛0
𝑛9
𝑛5
𝑛𝑀𝑀𝐴
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Conformation of BCP chain (GD-state)
Parallel BCP chains
Vertical PMMA blocks
Parallel PMMA blocks
PMMA blocks are nearly vertical to the bottom in the region where the vertical PMMA lamellar patterns are connected toward the bottom. This characteristic conformation of BCP chains is considered to be related with the origin of the grid defects.
中性化膜に対して垂直 Vertical PMMA blocks
↑Top-down
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Node density biased MC method
GD-state
terminal segment
junction segment
・・・・・
Field model particle model
Computer Physics Communications 145 267-279.
• The segment density distribution acquired using SCFT was transformed into the atomic representation using the node density biased MC method.
• Using this atomic representation as initial chain conformations, we executed DPD simulations and investigated the defect annihilation dynamics.
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DPD simulation results
Firstly, grid defects were observed. And finally, the grid defects disappeared and the simulation converged into the equilibrium lamellar state.
15
Defect annihilation dynamics
Polymer chains are partially vertical.
Polymer chains are parallel
Both vertically and horizontally oriented polymer chains appeared randomly.
The polymer chains flipped down and flopped up randomly
(b)1000 steps (Transient state)
(c)10000 steps (Equilibrium lamellar)
(a)Initial state (GD state)
Vertically oriented
horizontally oriented
The defect annihilation dynamics of the grid defects could be understood as the change of the orientation of the BCP chains.
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Outline
Grid defects Experimental behavior Simulation results acquired using
self-consistent field theory(SCFT) Simulation results acquired using
dissipative particle dynamics (DPD)
Dislocation defects
Summary
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Polymer conformation in dislocation defects
𝑛𝑐𝑒𝑛𝑡𝑒𝑟 =Segment density distribution of the center node 𝑛𝑡𝑒𝑟𝑚𝑖𝑛𝑎𝑙 =Segment density distribution of the terminal node
Center node Terminal node
Single dislocation
Double dislocation
Perfect state
Self-consistent field theory
𝑛𝑐𝑒𝑛𝑡𝑒𝑟 − 𝑛𝑡𝑒𝑟𝑚𝑖𝑛𝑎𝑙
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Polymer conformation in dislocation defects
Terminal segment density is larger than the center segment density.
Terminal segment density is larger than the center segment density.
Terminal segment is localized in a specific region. The delocalization of the terminal segments is effective for defect mitigation.