Browsing by Author "Lung, CA"

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Study on optimization of annular off-axis illumination using Taguchi method for 0.35 mu m dense line/space
(1997-02-01)
Loong, WA
;
Tseng, JC
;
Chen, TC
;
Lung, CA
;
交大名義發表
The simulation and experiment study on optimizations of process factors under annular off-axis illumination (AOAI) using Taguchi method for design of experiment (DOE) for 0.35 mu m dense line/space in i-line was reported in this paper. The optimized simulation results for both resolution and DOF are as follows: inner ring sigma(i) = 0.35, outer ring sigma(o) = 0.70, NA = 0.5, negative bias on mask for line in dense line/space similar to 0.03 mu m (L/S = 0.320/0.380 mu m), positive bias on mask for isolated line similar to 0.03 mu m (iso. L = 0.38 mu m), overlapped DOF (dense + isolated) similar to 1.86 mu m, exposure dose similar to 278 mJ/cm(2). The experimental results are in good agreement with simulations. The optimized results by experiments with a NA of 0.57 and with AOAI are as follows: inner ring sigma(i) = 0.35, outer ring sigma(o)= 0.70, negative bias on mask for line in dense line/space similar to 0.015 mu m (L/S=0.335/0.365 mu m), positive bias on mask for isolated line similar to 0.03 mu m (iso. L = 0.38 mu m), overlapped DOF (dense + isolated) similar to 1.7 mu m, exposure time similar to 520 ms (exact dose uncertain). Without AOAI but with the same mask bias, the overlapped DOF is similar to 1.2 mu m by experiment. The overlapped DOF from mask patterns without any bias (L/S = 0.35/0.35 mu m; iso. L = 0.35 mu m) with 1/2 AOAI is similar to 0.93 mu m; and from conventional illumination without mask bias is up to similar to 0.72 mu m at most. The DOF, proximity effect and resolution for dense L/S are obviously improved from 1/2 AOAI exposure after optimization if compared with conventional exposure. The Taguchi method is also proved valuable in this study.
TiSixOy as an absorptive shifter for embedded phase-shifting mask in 248 nm and the modification of R-T method for the determination of shifter's n and k
(1998-03-01)
Loong, WA
;
Chen, CW
;
Chang, YH
;
Lin, CM
;
Cui, Z
TiSixOy as an absorptive shifter (embedded layer) for attenuated phase-shifting mask (APSM) in 248 nm wavelength is presented. TiSixOy thin film was formed by plasma sputtering of Ti (25 similar to 55 W) and Si (200 similar to 250 W) under Ar (30 seem) and oxygen (0.1 similar to 0.4 sccm). For required phase shift degree theta=180 degrees, calculated thickness d(180) of TiSixOy Film is within the range of 87 similar to 120 nm depending on its reflectivity R, transmittance T, refractive index n and extinction coefficient k. Taguchi design of experiment has been applied to study the plasma etching selectivity of TiSixOy over APSM's substrate quartz (SiO2), under Cl-2:NF3=20:30 seem; 50 W and 60 mtorr, selectivity of 10:1 similar to 35:1 was observed. Modifications of reflectivity-transmittance (R-T) method have been developed for the determination of this absorptive shifter's n and k.