Design specific variation in pattern transfer by via/contact etch ...

Calibration/Prediction –ARC Etch
� Correction for Microloading nature of BARC etcing is added:
CD BARC.
o
CDLitho
γ
i
CD BARC . o − CD Litho = δ '+
αγ O [ 1 − β ( 1 − κD
)]
CD
Litho
. o = CD Litho ⋅ { δ + αγ [ 1 − β ( 1 − κD
)] }
α, β, δ, κ : calibration parameters.
CD BARC
O
: Simulated BARC CD opening prior to main
etching.
: Simulated resist opening CD using CM1 resist
model (calibrated on BARC opening CD
measurements)
: Normalized flux of neutral i.
: Density of resist opening.
� D(r
The ) term ββββ(1-κκκκD) is introduced to explain carbon assisted
polymer formation. Carbon in resist film is considered to be the
source.
� CDSEM measurement error of 3nm is taken into
account. TRS 2001 eds. Metrology, p.8
� Result : R 2 = 0.82
CD, nm
Simulated, nm
300
280
260
240
220
200
180
285
275
265
255
245
235
225
215
205
Measured
Simulated
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
y = 0.85x + 33.52
R2 = 0.823
Via No.
195
195 205 215 225 235 245 255 265 275 285
Measured, nm
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