The potential for extending the numerical aperture (NA) in order to develop devices beyond the 45-nm node has been investigated using a 157-nm microstepper exposure tool at 0.90NA (third generation) and verifying the resolution limit of several different resolution enhancement techniques. It was observed that with 157-nm lithography at 0.90NA a 60-nm line and space (L/S) and a 50-nm isolated line could be formed by using an attenuated phase shifting mask (Att-PSM), and that a 50-nm L/S and a 35-nm isolated line could be formed by using an alternating phase shifting mask (Alt-PSM). The influence of the flare for the same pattern sizes was more severe for the L/S pattern rather than isolated line. However, it was the most difficult to image an isolated line with an Att-PSM, which was limited with a tolerance to the flare of less than 1%. Furthermore, the requirement of more than 0.93 for lens NA was confirmed in order to fabricate half pitch 65-nm node device with Att-PSM and half pitch 45-nm node device with Alt-PSM. Results obtained in the pattern formation of 45-nm node with an Alt-PSM confirmed that a 35-nm line could be formed down to 140-nm pitch, a 40-nm line could be formed down to 135-nm pitch, and a 45-nm line could be formed down to 100-nm pitch. It has been demonstrated that 157-nm lithography could find application to half-pitch 65-nm and 45-nm node devices.
[1]
S. Irie,et al.
Novel resist pattern transfer process for 70 nm technology node using 157-nm lithography
,
2002,
2002 Symposium on VLSI Technology. Digest of Technical Papers (Cat. No.01CH37303).
[2]
Masahiro Nakagawa,et al.
Catadioptric lens development for DUV and VUV projection optics
,
2003,
SPIE Advanced Lithography.
[3]
Shigeru Sakuma,et al.
Nikon F2 exposure tool development
,
2003,
SPIE Advanced Lithography.
[4]
Toshiaki Motonaga,et al.
The development of bilayered TaSiOx-HTPSM (1)
,
2001
.
[5]
Toshiro Itani,et al.
157nm Lithography with High Numerical Aperture Lens for the 70nm Technology Node
,
2003
.
[6]
Raymond J. Hung,et al.
Development of SSQ Based 157 nm Photoresist.
,
2002
.
[7]
Toshiro Itani,et al.
Wavefront aberration measurement in 157-nm high numerical aperture lens
,
2003,
SPIE Advanced Lithography.