Vertical distribution of photo acid generator (PAG) inside CA-type photoresist is inferred from X-ray reflectivity (XRR)
analysis which gives the information on the vertical electron density profile of thin film. The difference between the
density distribution of normal photoresist and pure resin indicates the approximate distribution of PAG. The electron
density profile of each film is obtained by fitting method for the XRR results based on distorted wave Born
approximation (DWBA) approach. In this study, trends in density distributions varied by concentration of PAG suggest that the inhomogeneous distributions of PAG near the surface or interface of photoresist film occurs due to interactions between PAG molecules and substrate, or polymer resin. Distributions with low concentration of PAG (2 wt%) show that the PAG molecules tend to be concentrated near the surface of photoresist, while over-load of PAG (20 wt%) results in the density increase near the interface region.
To obtain high resolution and sensitivity and low line width roughness (LWR), the resist film homogeneity is thought to
be the key requirement of extreme ultraviolet lithography (EUVL) resist materials. We have synthesized of a new class
of chemically amplified molecular glass resists containing rigid triphenolic cores which are protected by flexible side
chains. We analyzed the electron density distribution of resist films (70 nm) by using X-ray reflectivity (XRR). The
effects of protection ratio, high and low activation protecting groups, chain lengths have been tested using selected
molecular resist. We discuss the effects of the chemical structures of new molecular resists on EUV lithographic
The effect of water-contact time on the roughness increment of patterned photoresist (AZ5214) was investigated by AFM analysis and the reason for the roughness increment was studied by the gravimetric experiment and the ellipsometry method. New method for calculating RMS line edge roughness from AFM raw data and the model of immersion lithography for experimentation were established. From the gravimetric experiments, it was confirmed that the diffusion of water into photoresist film is ruled by Fick's law. It was suggested that the amount of the swelling which follows the diffusion of water would be the reason for the roughness increment during rapid evaporation of water. As a result, the roughness of both the patterned line edge and the surface were proportioned in the root of water-contact time at the initial time and it was the same as the results in previous gravimetric experiments.