Current Status of EUV Flood Exposure Tool at NewSUBARU BL03

Abstract

Challenges of EUV lithography include the development of resists with high resolution, high sensitivity, low line-width roughness, and low outgassing. Thus, our research group has developed various evaluation systems installed at the NewSUBARU synchrotron radiation facility and promoted research for EUV lithography. In particular, BL03 is a beamline specialized for EUV flood exposure for 4-inch wafer and used to evaluate sensitivity and outgassing of resists.

At the EUV flood exposure tool, the synchrotron radiation light is monochromated to EUV with seven reflections by Mo/Si multilayer mirrors. The centroid wavelength of the total reflectivity spectrum is 13.57 nm. The beam size on the sample surface is 3 mm (H) × 4 mm (V), and the EUV irradiation intensity is estimated to be 0.5 mW/cm² at the storage ring current of 350 mA. We can take max 25 shots for each sample by moving the sample and obtain a contrast curve. About outgassing evaluation, the highly sensitive quadrupole mass spectrometer (QMS) that can measure the mass numbers of ion species from 1 to 512 is equipped in this system, and we can analyze outgassing component under EUV irradiation. This system supports fundamental EUV resist development including screening of newly developed resists.