Session Index

The overlay (OVL) measurement is an essential process control element of a scanner in advanced lithography. According to the report of the International Roadmap for Devices and System 2020, the OVL tolerance of a scanner decreases as the semiconductor process node advances. For example, the allowable OVL value is about 3.6 nm in the case of the dynamic random-access memory (DRAM) components, and the required OVL metrology precision must be as small as 10% of the allowable OVL value, i.e., 0.36nm. The diffraction-based measurement (DBO) was widely used as the technology node less than 20nm. The DBO metrology has overlapping targets, and the OVL value is determined by measuring an intensity unbalance in diffracted light. According to the DBO measurement principle, the measured OVL signal is an asymmetric diffraction signal generated by the measurement target, and a linear calculation model calculates the OVL value. However, since the wafer processing effect of the etching process and the chemical-mechanical polish (CMP) process caused the deformation of the measurement target profile, and then it will result in the OVL measurement error. Hence, in this paper, we proposed a robust and wafer-less measurement wavelength selection methodology based on the FDTD simulation for the measurement target with an asymmetric profile structure

  Preview abstract

By applying optical scanning holography (OSH) to three-dimensional holographic microscopy, the twin image and the zeroth order light arose in conventional digital holography can be suppressed. In addition, the OSH can record an incoherent hologram, which makes the fluorescence holography possible.

  Preview abstract

In this study, a commercial microwave transceiver system with a wavelength and frequency of 2.85 cm and 10.525 GHz was diagnosed. The characteristics of this system was tested, including the output waveform, the wavelength, the polarization state, the operational orientation of the transceiver. With the system, the Brewster's angle and Malus' law were verified. The diffraction intensity of metal-wired lattice structure was observed which can be used to confirm the interplanar spacing and evaluate the wavelength of the wave source. Considering the unique characteristics of microwave-matter interactions, the operation characteristics of microwave transceiver system should be known before advanced applications.

  Preview abstract

The digital holographic microscope uses a lensless Fourier transform system combined with holographic optical elements[1]. Due to its light weight, small size and high resolution, various noises are still observed. This article focuses on "Analysis of observed noise and possible solutions for light guide elements and digital reconstruction processes".

  Preview abstract

The volume holographic optical element (VHOE) functioned as micro-lens could be applied to the light field out-coupler of the near-eye display. In this paper, we propose an optical model of the micro-lens functioned VHOE, based on a 1-D analytical solution. The effects of image color distribution and viewing angle variation can be analyzed.

  Preview abstract