Localized Resist Heating Due to Electron-Beam Patterning During Photomask Fabrication
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Date
2001Author
Wei, Alexander C.
Publisher
University of Wisconsin-Madison
Metadata
Show full item recordAbstract
As the semiconductor industry continues to shrink the size microelectronic
components, sources of critical dimension error that were unimportant in the past
have surfaced, and must be resolved. Among these errors is the proximity heating
effect. As an optical mask is patterned using an e-beam, there is heat diffusion away
from the area being patterned. Due to the increase in temperature, the resist
surrounding the patterned area increases in sensitivity and becomes more prone to
development from scattered electrons. The unexpected development of resist and
distortions due to thermal gradients can cause the final pattern to differ from the
intended pattern.
Unfortunately, there is no method to predict the magnitude of these errors.
Guess and check methods are not feasible in the production environment due to the
limited number of chip manufacturing tools, and the need to produce saleable
products on these tools. Consequently, a method is needed to predict the magnitude
and location of these errors. The topic of this thesis is to investigate the thermal
response of the optical mask due to direct patterning using a finite element program,
ANSYS. The results from this thesis, resist temperature as a function of position and
time, can then be combined with experimental data relating the temperature history of
the resist with its sensitivity, and Monte Carlo simulations that predict the scattering
of electrons as they penetrate an optical substrate to yield the percentage of resist
development at every point on the mask. The results of this analysis can then be compared with the desired pattern. Any regions containing unacceptable errors can
then be redesigned.
Subject
Thesis (M.S.)--University of Wisconsin--Madison, 2001.
Dissertations Academic Mechanical Engineering.
University of Wisconsin--Madison. College of Engineering.
Permanent Link
http://digital.library.wisc.edu/1793/7640Description
Under the supervision of Professors W. Beckman, J. Mitchell, and R. Engelstad; 72pp.
Citation
Wei, A.C. (2001). Localized Resist Heating Due to Electron-Beam Patterning During Photomask Fabrication. Master's Thesis, University of Wisconsin-Madison.