Evaluation systems of F 2 laser lithography materials

Abstract

In this paper, we present an evaluation system for F 2 laser lithography masks and resists and we report preliminary test results. The evaluation system has two subsystems that are based on very accurate measurement technology. One subsystem is used for mask evaluation, the other subsystem for resist evaluation. The mask subsystem consists of two units. One unit evaluates real size 6025 binary masks placed horizontally as inside steppers. This unit measures three parameters: 1) the real time in-situ transmittance at 157nm during F 2 laser irradiation, 2) the in-situ VUV transmittance using a VUV spectrophotometer and 3) the deformation of the pellicle. The precision of transmittance measurement at 157nm is +/-0.5%. The precision of the pellicle deformation measurement is +/-0.1μ m. The second unit of the mask subsystem collects samples of the mask outgassing and analyzes them in a gas chromatograph mass spectrometer. The resist evaluation subsystem consists of three units. 1) One unit determines negative effects of outgassing resist contaminants on the transmittance of optical materials under F 2 laser irradiation, 2) the second unit analyzes the outgassing from resists and 3) the third unit examines the effectiveness of exposure tool purge nozzles to reduce outgassing contamination.