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Business Unit Electronic Materials . . ..
Transcript of Business Unit Electronic Materials - Frontier Homepage...
Business Unit Electronic Materials
.. . .
Business Unit Electronic Materials
.. . .
Sloped Sidewalls In Novolak-Based DUV Resists
High unbleachableabsorption leads toheavily sloped sidewallsin novolak-based resists imaged at 248 nm.
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248 nm: Polyhydroxystyrene rules!
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Optical Lithography:Resin Absorption and Resist Chemistry
Beyond i-line, resist chemistry for optical lithographies is dominated by the demands of the base polymer absorption:
� 248 nm resists:� Novolak is opaque use of PHS� PHS is not inhibited use of CA deprotection
� 193 nm resists:� PHS is opaque use of aliphatic compounds� Aliphatics etch too fast use of alicyclic compounds
� 157 nm resists:� “Everything” is opaque fluorocarbons, silanols, or, finally,
the end of SLR resists?
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.. . .Synthetic Routes To Poly(4-Hydroxystyrene)
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.. . .Dissolution Inhibition for 248 nm
PHS resin+ photolysis products
diss
olut
ion
rate
[µm
/min
]
novolak resin+ diazonaphthoquinone sensitizer
novolakresin
novolak resin+ photolysis productsR
R0
diss
olut
ion
rate
[µm
/min
]
PHS + sensitizer
PHS resinR
R0
PHS does not work well for dissolution inhibition systems!
New imaging scheme needed!
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Beyond Novolaks: Chemically Amplified Resists
The original photoevent generates a catalyst for solubilization (typically a proton). The photoevent is amplified by the number of cycles each proton catalyzes.
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.. . .Basic Chemistry: Functional Group Deprotection
t-Alkyl Deprotection
high TONrequires superstrong acidsrequires non-nucleophilic anionsrequires higher bake temp.
Today, all commercial resists use at least one of two approaches:
Acetal Deprotection
lower TONworks with any mineral aciddoes not require non-nucleophilic anionsrequires no or lower bake temp.
O OHH
O OHH3C
O
R
HH
O R
H3C
HO R
H +
+
+products
PAG
O O
OO H
O OHH
CO2++
H
H +PAG +
products
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CH2
CH3
O
O
OH O
High And Low Activation Energy Protective Groups
OH O
O
n n
NO O
O
O
n
OH O
R’
OR
O
OR
R'
n
OH
CH3
O
O
acetal
n n
t-butylester/ether,sec. alkyl
low E a
high E a
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Medium Activation Energy Protective Groups
O
O OH O
OO
n n
CF3 CF3F3CF3C
OH O
OO
n
NO O
O
O
OO
CH2CH2
CH3 CH3
OO
O O
t-BOC
medium E a
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DUV Resin Technology Potential Comparison
0.2
0.4
0.6
0.8
1Res L&S
Res IL
DOF L&S
DOF ILIso/Dense Bias
PED
LER
t-Butylester
0.2
0.4
0.6
0.8
1Res L&S
Res IL
DOF L&S
DOF ILIso/Dense Bias
PED
LER
Acetal
0.2
0.4
0.6
0.8
1Res L&S
Res IL
DOF L&S
DOF ILIso/Dense Bias
PED
LER
t-Butylether
0.2
0.4
0.6
0.8
1Res L&S
Res IL
DOF L&S
DOF ILIso/Dense Bias
PED
LER
t-BOC
0.2
0.4
0.6
0.8
1Res L&S
Res IL
DOF L&S
DOF ILIso/Dense Bias
PED
LER
AcetaltBu-Ether
tBOCtBu-Ester
for 0.18 µm Technology
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OH
O O
H3CCH3
CH3
O
O
CH3
Genealogy of DUV Positive Photoresist Resins
OH OH
OH
O O
H3CCH3
CH3
O O
O
O
CH3
CH3
CH3
O
O
CH3
CH3
CH3
OH
O O
H3CCH3
CH3
O OH
O
H3C
O OH
O
O
CH3
CH3CH3
O OH
O
O
CH3
CH3
CH3
O
O
CH3
AcetalAcetal
ESCAPESCAP
t-BOCt-BOC
O OH O
O
CH3
CH3
H3C
H3C
L&S
C/H
IL
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Meta-cresol novolak
Poly-(4-hydroxystyrene)
Polyacrylates(aliphatic)
200 225 250 275 300 325 375350 400175
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0.0
Wavelength [nm]
Abs
orpt
ion
coef
ficie
nt [1
/µm
]
ArF193 nm
KrF248 nm
i-line365 nm
Source: R.D. Allen et al., IBM J. Res. Develop. 41 (1/2), 95-104 (1997)
Absorption of Polymers for Photoresist Usage
99-0220
