Wavefront measurement interferometry at the operational wavelength of extreme-ultraviolet lithography
Yucong Zhu1, Katsumi Sugisaki, Masashi Okada
1EUVA Sagamihara R&D Center, 1-10-1 Asamizodai, Sagamihara, Kanagawa 228-0828, Japan. zhu.yucong@nikon.co.jp
Abstract:
Two basic types of interferometer, a point diffraction interferometer (PDI) and a lateral shearing interferometer (LSI) suitable for operation in the extreme-ultraviolet (EUV) wavelength region, are described. To address the challenges of wavefront measurement with an accuracy of 0.1 nm rms, we present a calibration method for the PDI that places a mask with two large windows at the image plane of the illumination point light source and a general approach to deriving the phase-shift algorithm series that eliminates the undesired zeroth-order effect in the LSI. These approaches to improving the measurement accuracy were experimentally verified by the wavefront measurements of a Schwarzschild-type EUV projection lens.
More Related Videos
Related Concept Videos
Inductively Coupled Plasma Atomic Emission Spectroscopy: Instrumentation
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used.
Atomic Force Microscopy
The AFM Probe
The probe is regarded as the heart of any AFM setup and comprises the...
Atomic Fluorescence Spectroscopy


