J. Aizenberg et al., IMAGING PROFILES OF LIGHT-INTENSITY IN THE NEAR-FIELD - APPLICATIONS TO PHASE-SHIFT PHOTOLITHOGRAPHY, Applied optics, 37(11), 1998, pp. 2145-2152
We describe a method of imaging the intensity profiles of light in nea
r-field lithographic experiments directly by using a sensitive photore
sist. This technique was applied to a detailed study of the irradiance
distribution in the optical near field with contact-mode photolithogr
aphy carried out by use of elastomeric phase masks. The experimental p
atterns in the photoresist determined by scanning electron microscopy
and atomic force microscopy were compared with the corresponding theor
etical profiles of intensity calculated by use of a simple scalar anal
ysis; the two correlate well. This comparison makes it possible to imp
rove the theoretical models of irradiance distribution in the near fie
ld. Analysis of the images highlights issues in the experimental desig
n, provides a means for the optimization of this technique, and extend
s its application to the successful fabrication of test structures wit
h linewidths of similar to 50 nm. (C) 1998 Optical Society of America.