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The current semiconductor lithography process is in the high volume production phase of 193nm high NA (Numerical
Aperture) exposure, and further reaching the high volume production phase with 193nm immersion exposure
lithography. As a result of miniaturization of the devices, it has becomes necessary to reduce the concentration of basic
compounds (such as ammonia, amines, and N-methyl-2-pyrrolidone (NMP), which are used to insolubilize the chemical
amplified resist in developing process, in the environment surrounding the wafer. For this purpose, chemical filters are
used. In the clean room, in addition to these basic gases, there exist various organic compounds and the effects of organic
compounds on the chemical filter cannot be ignored. This paper reports the results of basic research on the adsorption
behavior of physical adsorption under the presence of the above-mentioned basic compounds and ion exchange reaction.
Then the adsorption behavior of activated carbon chemical filter impregnated with acidic chemicals and strongly acidic
cation exchange chemical filter for basic compounds was studied in the coexistence of organic components. The
performance of impregnated activated carbon chemical filter deteriorates due to the coexisting organic compounds
because removal of NMP is based on the physical adsorption mechanism. On the other hand, the performance to remove
ammonia and NMP of strongly acidic cation exchange chemical filter is not affected by organic compounds because the
filter exchanges ions with weakly basic compounds. The strongly acidic cation exchange chemical filter can provide
desired performance for basic compounds under an actual clean room environment.
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