Akira Miyake

Finite-element analysis of the rotor/stator contact in a ring-type ultrasonic motor

A way to understand mechanical characteristics of an ultrasonic motor is presented. First, the vibration mode of a stator is calculated using a finite-element method (FEM) code. The path of the elliptic motion of the stators teeth is obtained. The computed vibration mode at the surface of the stator is compared with that measured by an electrooptical displacement transducer. Next, the contact condition of the rotor/stator is calculated. The displacement and velocity of the rotor/stator, the distortion of the stick/slip area, the rotational speed of the rotor, and the friction loss of the motor are obtained. The calculated rotor displacement and torque-rotational speed curve correspond closely to the experimentally measured ones. The internal loss of the rotor/stator and the loss of the supporting felt are measured. The total loss of these losses and the calculated friction loss agree with the measured total loss. The calculated and the measured efficiency of the motor also agree.<<ETX>>

The contact mechanism of an ultrasonic motor

The mechanical characteristics of a ring-type ultrasonic motor are clarified. The finite-element method (FEM, MSC/NASTRAN) was used to obtain the shape of the elliptic motion at the surface point of projections. The vibration mode of projections was measured by using an electrooptical displacement transducer made by Zimmer KG. The accuracy of the simulation was confirmed by comparing the calculated results with the measured results. The dynamic contact condition of a stator and a rotor was calculated by using the FEM (JNIKE3D). The simulated displacements, T-N (torque-rotating-speed) curve, loss power and efficiency are compared with the experimental results.<<ETX>>

Suppression of columnar-structure formation in Mo-Si layered synthetic microstructures

We have previously reported that columnar-structures were formed in electron beam (EB) deposited and DCmagnetron sputtered Mo-Si layered synthetic microstructures (LSMs). The columnar structures reduced x-ray reflectivity by roughing layer interfaces of the LSMs. We here investigated the conditions to suppress columnar structure formation, by varying the substrate temperature (T9) in EB deposition and the argon pressure (PAT ) in D C- and RF-sputtering. In the EB deposited LSMs, the columnar structure disappeared and almost uniform LSMs were obtamed both at T□ 400°C and T9< -155°C. In the DC- and RF-sputtered LSMs, the columnar structure formation was suppressed by lowering PAr. The measured x-ray reflectivity of the LSMs increased according to the suppression of the columnar structure formation.

Phase measurement of reflection of EUV multilayer mirror using EUV standing waves

Projection optics of an EUV lithography system consists of multilayer mirrors. Phase of the incident beam is shifted on reflection at the multilayer mirror [Y. Watanabe et al., Jpn. J. Appl. Phys. 30, 3053 (1991)]. If the phase shift at reflection of a multilayer is not well controlled, it becomes the cause of wavefront aberration. The phase shift depends on the incident angle and the wavelength of the beam. The phase shift is also dependent on the structure of the multilayer. Certain kinds of structural change cause non-negligible variation of the phase shift with very little change of wavelength dependency of reflectivity. Therefore, not only reflectivity measurement but also measurement of phase shift is essential to manufacture multilayer mirrors for projection optics. X-ray standing wave technique has been used to characterize multilayer structure [B. Lai et al., Nucl. Instrum. Methods Phys. Res. A 266, 684 (1988); T. Kawamura and H. Takenaka, J. Appl. Phys. 75, 3806 (1996)]. Intensity of electric fi...

Analysis of carbon deposition on multilayer mirrors by using two different beamlines

It is very important to mitigate oxidation of multilayer mirrors (MLMs) and carbon deposition onto MLMs to extend the lifetime of EUV exposure tool. In order to estimate the lifetime, we have to figure out scaling law. Previous results at EUVA have shown that carbon deposition rate on MLMs is not proportional to every hydrocarbon partial pressure and every EUV intensity3-4. In this study we focused on carbon deposition on Si-capped multilayer mirror. We made experiments of EUV irradiation to the MLMs using two different apparatuses. One is connected to a beamline (SBL-2) of synchrotron radiation facility Super-ALIS in the NTT Atsugi research and development center, and the other is connected to a beamline (BL9) of synchrotron radiation facility New SUBARU in the University of Hyogo. As the result of experiments, we found that different carbon deposition rate occurred on the different beamlines, although they have the same average EUV intensity. We present differences of carbon deposition rate on MLMs between two different beamlines and estimation of carbon deposition rate on EUV tool analyzing dependences of carbon deposition rate on characteristics of EUV source.

Double-Pass Amplification in Ge Soft X-Ray Laser with a Polarizing Half-Cavity

The control of polarization of soft X-ray lasers is presented. Double-pass amplification in a soft X-ray laser with a half-cavity comprising a multilayer polarizer and a normal incidence reflector has been tested. Successful results have been obtained using a curved-slab target for the lasing line at 19.6 nm due to the J=0–1 transition of the collisional-excitation neonlike germanium soft X-ray laser.

Fabrication and evaluation of Cr-C multilayer mirrors for soft x rays

We have selected Cr and C as a material pair of multilayer (ML) mirrors for soft x rays at the wavelength near 5 nm. The Cr-C ML structures have successfully been fabricated with rf- magnetron sputtering. The ML structures have been characterized with transmission electron microscopy (TEM), x-ray diffraction, and reflectivity measurement by SR light. From the observation of TEM images, Cr-C MLs had uniform and less-defective layered structures with the d-spacing down to 2.4 nm. Reflectivities at normal and grazing incidence were remarkably decreased with decreasing the ML d-spacing. Normal incidence reflectivity at 5 nm was as high as 7%. The regularity of the d-spacing of the MLs was evaluated with a moire image that was formed by putting a reference stripe pattern on the cross-sectional TEM micrograph. Compared to Ni-C MLs, Cr-C is a preferable material combination for x-ray mirrors for shorter wavelength and normal incidence.

Investigation of the resist outgassing and hydrocarbonaceous contamination induced in multi-electron-beam lithography tools

In emerging high-vacuum multi e-beams exposure tools, the release of hydrocarbonaceous species (precursor) by resists outgassing is unavoidable and leads to premature contamination of optics projection systems. In this work, we present an experimental methodology aiming at resist outgassing qualification. A specific experimental setup was designed to monitor the induced outgassing phenomena by irradiating resist coated on 100mm silicon wafer. The wafer can be exposed through specific silicon micromachined membranes (called mimics) that are representative of the optics projection system usually embedded in real multi e-beam exposure tools. A Quadrupole Mass Spectrometer (QMS) is plugged into the vacuum chamber and enables in-situ analysis of the by-products outgassing. Combining this tool with the Thermo Desorption - Gas Chromatography coupled to Mass Spectroscopy (TD-GC-MS) analysis, we could not only determine the outgassing amount of different resists but also identify all the outgassed by-products and their origin. Finally, the Focus Ion Beam combined to Scanning Electron Microscopy (FIB-SEM) and X-ray Photoelectron Spectroscopy (XPS) characterization techniques were used to determine the contamination layer thickness and elementary composition, respectively. A first process oriented conclusion from this work shows that the use of a thin topcoat layer can considerably reduce the resist outgassing amount and, consequently, the hydrocarbonaceous contamination layer induced on the mimics. The outgassing amount as well as the top-coat efficiency was shown to be mainly dependent on the resist chemical properties. The contamination layer growth was shown to be dependent on e-beam current density and hydrocarbon pressure in the vicinity of the mimics.

LPP-based reflectometer for characterization of EUV lithography systems

An EUV reflectometer, based on a laser-produced plasma (LPP) light source, has been developed for characterization of EUV lithography systems. The reflectometer consists of the LPP light source, a prefocusing toroidal mirror, a grating monochromator, a polarizer, a beam intensity monitor, a refocusing toroidal mirror and a sample stage. The LPP light source is driven by a Nd:YAG laser; the laser beam is focused onto a copper tape target. A debris mitigation system that uses a rotating shutter was developed. Higher-orders formthe grating monochromator were suppressed to less than 0.2% of incident beam intensity by total reflection of three grazing incidence mirros. In order to compensate for beam intensity instability, a beam intensity monitor using a grating beamsplitter was installed between the refocusing mirror and the sample. Beam intensity instability can be corrected to less than 0.1% by using the beam intensity monitor.

Development status of Canon's full-field EUVL tool

EUVL is the most promising candidate of 32 nm generations and beyond. In this paper, we present Canons development status of EUVL technologies. The system design of the EUV full field high volume manufacturing tool (VS2) is under way. The specification of VS2 is presented in this paper. The fabrication of six-aspheric-mirror prototype projection optics (PO1) of NA 0.3 has been started. The PO1 is fabricated to evaluate and improve our technologies of polishing and measuring the figure of mirrors. We present some results of the figuring accuracy of the mirror. EUVL will be required to resolve sub-twenty nm L&S patterns. We are studying off-axis illumination technologies and high- NA technologies. The simulation results of the resolution capability and the DOF are presented.