Kouji Toyoda's research while affiliated with Mohawk Innovative Technology, Inc. and other places

Publications (17)

Article
The method as well as an appropriate instrumentation for measuring phase changes of reflected light is described. The phase changes on samples of Au, Al, Ag, and Cr evaporated films are measured for five wavelengths (lambda) from 442 to 633 nm, with respect to the phase change at the glass-air interface, where it should be zero. The measured result...
Article
A compact laser interferometer combined with a mechanical scanner has been developed for precise microlinewidth measurements in regular scanning electron microscopes (SEMs). Optical components and a piezodriven mechanical table are integrated on a small disk 130 mm in diameter. The device is so compact that it can be installed in the vacuum chamber...
Article
The paper proposes a robot calibration system. A new cat's-eye retroreflector with n=2 and interferometric scanning mechanisms with spherical seat bearings was shown to improve the measurement accuracy of the multilaser coordinate measuring system. The paper therefore describes a two dimensional self-calibration method for industrial robots by empl...
Article
A small interferometer for the use of precise scanning electron microscopy has been developed. Optical components and a piezo-driven mechanical scanner are integrated on a small disk of 130mm in diameter. the device is small enough to be installed in the vacuum chamber of regular scanning electron microscopes (SEMs), and enables absolute linewidth...
Article
A new method for evaluating the coordinate error of commercial CMMs by using a newly developed three-dimensional tracking laser interferometer is proposed. The length between a moving Cats'-eye retroreflector set to the probing head of a CMM and the rotation center of the 3 D tracking interferometer is measured and used for estimating the coordinat...
Article
A sample consisting of different metals in the same plane is fabricated, and its surface profile is measured by interferometry. In spite of the flat surface, a virtual step height (max. value equals 33 nm) is measured at the boundary of the two adjacent metals. The measured step height corresponds to the difference in the phase change of reflected...
Article
Trial linewidth standards for the calibration of scanning electron microscopes (SEM's) used in semiconductor production have been manufactured and evaluated. A quantitive investgation of the relationship between peak-to-peak linewidth and cross sectional dimension has been made. The results show that the peak-to-peak values are 7nm smaller than the...
Article
A highly accurate co-ordinate measuring system for a large measurement area (larger than 1m×1m) is developed. The system consists of two target-tracking stations, each with a laser-interferometer and a twin cube-corner mirror attached to a target. Since the co-ordinate of the target is computed from the radial distances between the target and the r...
Article
The coordinates deviation of a CMM (three coordinates measureing machine) is estimated as error vectors within 1 μm of uncertainty, by using 2 laser tracking stations. The error vectors were estimated as the differences between coodinates data of the instrument and estimated positions by the least square method. The calibration or correcting method...
Article
A coordinate measuring system with two target-tracking laser interferometers is developed. Each interferometer measures the radial distance between the corner point of a target corner-cube mirror and the rotation center of the tracking. 2 D coordinate value of the corner point is computed from these radial distances and a priori known distance betw...
Article
An absolute linewidth measuring system, based on a scanning electron microscope (SEM), is developed to measure critical dimension (CD) of VLSIs (very large scale integrated circuits). The system employs two laser interferometers for the absolute scales of the X and Y axes, while the electron beam is used to detect microfeatures on the silicon chips...
Article
A metrological electron microscope system to measure critical dimensions of microfeatures in VLSI production has developed. The system has two laser interferometers as absolute scales, whereas the electeron beam is used to detect the microfeatures. The resolution of the interferometer for the main scanning direction X is 0.8nm (λ/800), and system r...
Article
This paper covers various characteristics of a micro-scanning table. Some of the characteristics discussed include stability, pitch, and yaw of the table. Other topics covered are smoothness of table motion, leaf spring utilization, and elastic deformation analysis. The table has sufficient characteristics for the measurement of microdimensions of...
Article
A rotating specimen holder device for use in the vacuum chamber of a SEM (scanning electron microscope) is developed by using a piezodriven mechanism. The mechanism consists of piezoelectric elements, clamps, and actuators that work as feeders to rotate the spindle. It is specially designed to eliminate the magnetic field influence of standard moto...
Article
The rotational speed control characteristics of a circular traveling wave motor are investigated. This motor is an ultrasonic motor driven by a specially designed piezoelectric vibrator. There are various parameters for controlling rotational speed due to the influence of friction and resonance between rotor and stator. In this paper the dependence...

Citations

... Moreover, the use of absolute distance measurement (ADM) offers the convenience of re-establishing distance data after a beam-break event, as well as dynamic measurement related to speed improvement [5,6]. However, the uncertainty associated with angular information remains the main source of error in large-volume measurement [7]. Efforts to reduce this error have led to the use of multilateration tracking systems (MLTSs), in which angle measurement is entirely removed and only multi-distance information is used for three-dimensional (3D) coordinate measurement [8]. ...
... To interpolate the unit periods of (d/2) and (λ/2) in equations (9) and (10), some optical techniques (Hatsuzawa et al., 1994) can be used in the method. An interpolation order of 8000 or more is available with some commercial products for homodyne interferometers (BD96 @ SONY Manufacturing System, SP4800 @ MicroE System). ...
... The intensity of retro-reflected light in the direction of the source can be up to hundreds to even thousands of times higher than that of a diffuse target [24]. They have also been used together with a laser for making distance measurements in space [25], industrial [26], and robotics applications [27]. ...
... Scanning electron microscopy is the most developed method for visualizing reliefs [1][2][3][4]. This is associated with the fact that modern industry produces a large number of high-quality scanning electron microscopes (SEMs). ...
... Outgassing, heat transfer, and particle emissions are issues that must be addressed in vacuum work [10,11]. Reliability, always a concern when designing mechatronic systems, becomes especially important when the system is enclosed in a vacuum chamber. ...
... Figure 16 is a graph of the rotation speed n 1 with frequency. The FEM rotation speed n 1 is obtained according to a previous method [34]. The experimental and FEM methods are in good agreement. ...
... For surfaces having varying optical properties, e.g. surfaces composed of dissimilar materials, errors in topography measurement can be introduced by different phase changes on reflection [179,180]. Moreover, phase changes can combine with dispersive effects and give rise to 2π errors [31]. ...