SPIE Journal Paper | 1 April 2008
KEYWORDS: Line width roughness, Nanoimprint lithography, Electroluminescence, Diffusion, Photoresist materials, Absorbance, Extreme ultraviolet, Lithography, Photoresist processing, Extreme ultraviolet lithography
The use of a single figure of merit to judge resist performance
with respect to resolution, linewidth roughness LWR, and sensitivity is
proposed and evaluated. Chemically amplified photoresists used in advanced
lithography nodes need to fulfill stringent requirements for a considerable
number of resist and process characteristics. Along with resolution,
linewidth roughness and resist sensitivity are important examples
where the specifications have become very tight. Previously, it has been
shown that resolution, linewidth roughness, and resist sensitivity are fundamentally
interdependent. Hence, when evaluating or optimizing resist
performance, it is very important to take these three characteristics into
consideration simultaneously. We propose to combine these characteristics
into a single photoresist figure of merit KLUP. This figure of merit,
which is determined from sizing dose, imaging wavelength, resist thickness,
exposure latitude, acid diffusion length, linewidth roughness, and
pitch, allows for a direct comparison of very different resist formulations
independent of the exposure tool used. Thus, KLUP has great potential to
assist in evaluating resist performance for the next lithography nodes, for
both ArF and for EUV wavelengths.
