Patent Number: 6,295,123

Title: Multiple photon absorption for high resolution lithography

Abstract: Conventional optical lithography has a lower limit of about 180 nm because the projection system is opaque to radiation of wavelength shorter than this. This limitation has been overcome by using, in a standard photoreduction system, light in the form of a train of short duration high intensity pulses. Because of two-photon interactions, light having half the wavelength of the illuminating radiation is then generated in the focal plane. There are thus two aerial images present while the photoresist is being exposed. One is the conventional long wavelength image and its associated CD while the other is the short wavelength image with its smaller CD. Since the resist is sensitive to only the shorter wavelength, only the lower CD image remains after development.

Inventors: Wang; Chun-Ming (Kaohsiung, TW)

Assignee: Taiwan Semiconductor Manufacturing Company

International Classification: G03F 7/20 (20060101); G03B 027/72 (); G03B 027/42 (); G03B 027/54 (); F21V 009/16 (); G03C 005/00 ()

Expiration Date: 09/25/2018