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

Approximation of “Thin Polymer” Layer
� Rate of generation of active precursors on SiO2 surface by
ions penetrated the adsorbed layer is much higher than the
rate of their disappearance by means of etch reactions
� Rate of the reaction between silicon and fluorine atoms is
faster than the rate of reactions of polymer formation. ( ) ⎟⎟
M k′
Γ
C D CF2
H ≈
C
ρ S kRΓO
+ ketch
C ⎛ k ′ Γ ⎞
etchk
D CF
≈ Γ ⎜
2
ER K etchk
D CF 1− 2 ⎜
C
ηΓi
E0
kRΓO
+ ketch
Polymer Polymer thickness thickness (nm) (nm)
Polymer thickness (nm)
6
5
4
3
2
1
Exp
Cal
O2=8 cc
0
0 500 1000 1500
6
5
4
3
2
1
Exp
Cal
Ion Energy (eV)
O2=8 cc
0
0.00E+00 1.00E+17 2.00E+17 3.00E+17
CF2 flux (cm-2 s-1)
ER of SiO2 (nm/min)
ER of SiO2 (nm/min)
600
500
400
300
200
100
Exp
Cal
O2=8 cc
0
0 500 1000 1500
600
500
400
300
200
100
Exp
Ion Energy (eV)
O2=8 cc
Cal Tatsumi, T., Hikosaka, Y., Morishita,
S., Matsui, M., and Sekine, M., “Etch
rate control in a 27 MHz reactive ion
etching system for ultralarge scale
integrated circuit processing,” J. Vac.
Sci. Technol. A 17, 1562-1569 (1999).
0
0.00E+00 1.00E+17 2.00E+17 3.00E+17
CF2 flux (cm-2 s-1)
⎝
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17
⎠