Ultrahigh-speed fiber lasers operating at up to 40 GHz offer a clean longitudinal comb and a narrow linewidth. This makes them suitable for applications including optical comb generation, ultrahigh-speed optical pulse transmission including PSK, and as opto-microwave oscillators. In this paper, we describe recent progress on ultrafast fiber lasers and their applications to optical metrology.

The paper reviews methods for the measurement and analysis of high precision surfaces. A number of measurement techniques are discussed with the emphasis on the application of con-focal methods. The various techniques are compared in terms of measurement times, data density, and the ability to detect near vertical surfaces, and steps. The two sensing methods discussed are the auto-focus laser method and the white light methods. Particular applications considered are in the measurement of eroded electrical contact surfaces, spherical and near spherical surfaces, and MEMS. The particular emphasis here is on the metrology of such surfaces and devices and methods for the assessment of complex micro-machined surfaces. The paper points to a number of directions for improved metrology and discusses these in the context of the application given.

This paper presents a review of volumetric erosion studies applied to electrical contacts. The numerical methods presented are generic and could equally be applied to a number of areas where surfaces have been eroded or damaged. Equally there is no scale limitation of the surfaces to which the numerical methods can be applied. The paper starts with an introduction of the issues associated with the measurement of contact erosion, and then presents a summary of various hardware system for making 3D measurements of surfaces such as electrical contacts. This is followed by a review of the generic form fitting methods and also volume calculation methods. The paper concludes with a review of results taken from a test system for contact studies and from contact samples taken from commercial relays.

This paper describes a new measurement method of a CD-SEM with nanometer-level precision and good correlation with electrical characteristics for an actual device of ultra-large-scale integration (ULSI). With the decrease in feature size, the pattern to be measured tends to become a curved shape. In order to measure such a pattern within measurement precision on the order of 5 nm, two-dimensional measurement is effective. Here we report a new measurement algorithm featuring that the critical dimension is derived from the value of the area of a measurement pattern. We apply this measurement method to actual device of 64-Mbit DRAM and confirm the reproducibility of 3.6 nm for the gate linewidth measurement, and that of 5.6 nm for the hole diameter measurement. Furthermore, we verify that the measurement values of the gate linewidth have a strong correlation with the threshold voltage and those of the hole diameter also have a strong correlation with the contact resistance, respectively.

SEASAT synthetic aperture radar (SAR) echoes from the sea show beautiful images of storms over the ocean. However, the mechanisms by which such storm images are created have not yet been revealed very well. The core of these images is usually an echo-free hole which is attributed to the damping of the radar-detectable short gravity waves by the intense rain in the storm core. The bright area surrounding the core is believed to be caused by strong winds diverging from the downdraft which is collocated with the intense rain. The outer boundary of the bright area has been found to be associated with the classical gust front. During the Tropical Ocean Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA/COARE), continuous observations of rain by shipborne radars were carried out. One image of JERS-1 SAR taken in this period contains storms that were within the observation area of a shipborne radar. The SAR image and the rain-radar image are compared. Even though the signal-to-noise ratio of the SAR image is very low, there is good correspondence between heavy rain areas and some of the dark areas in the SAR image. The boundary of a rain-induced dark area is found to correspond approximately to the radar reflectivity factor (Z-factor) of 35dBZ or 5.5mm/h of rain.

A system for measuring the low frequency amplitude and phase noises was set-up, with employing a phase sensitive detector and phase-shifter. It is noted that both noises were partly correlated. The phase noise was explained by the transit time fluctuation due to the fluctuating diffusion coefficient. The amplitude noise reduction was demonstrated by applying the inverted output of the phase noise to the amplitude noise.

This paper applies the principle of radar polarimetry to the synthetic aperture frequency modulated continuous wave radar. First, the principle of monochromatic wave radar polarimetry using scattering matrix and polarization ratio necessary for introducing polarimetric imaging is given. In order to accommodate this principle to a wideband radar, a scattering matrix must be introduced, because FM-CW radar utilizes a wideband signal. This paper points out that the polarimetric target reflection coefficient obtained by the synthetic aperture FM-CW radar works as the scattering matrix element. This replacement, i.e., polarimetric reflection coefficient = the scattering matrix element, was verified by an experiment based on the polarization ratio which maximizes and minimizes a target. A radar system operative in the microwave X-band was successfully applied to the polarimetric detection of a metallic pipe of different orientations, demonstrating the validity of FM-CW radar polarimetry, and indicating an establishment of full polarimetric radar system.

Practical linewidth measurement accuracy better than 0.02 µm 3 sigma that meets the production requirement for devices with sub-half micron features, was achieved in a field emission scanning electron-beam metrology system (Hitachi S-7000). In order to establish high accuracy linewidth measurement, it was found in the study that reduction of electron-beam diameter and precise control of operating conditions are significantly effective. For the purpose of reducing electron-beam diameter, a novel electron optical system was adopted to minimize the chromatic aberration which defines electron-beam profile. As a result the electron beam diameter was reduced from 20 nm to 16 nm. In order to reduce measurement uncertainties associated with actual operating conditions, a field emission electron gun geometry and an objective lens current monitor were investigated. Then the measurement uncertainties due to operating conditions was reduced from 0.016 µm to 0.004 µm.