A modified illumination technique recently developed is known to improve the resolution and DOF (depth of focus) dramatically. But, it requires substantial modification in optical projection system and has some problems such as low throughput caused by low intensity and poor uniformity. And it is very difficult to adjust illumination source according to pattern changes. To solve these problems, we developed a new illumination technique, named ATOM (Advanced Tilted illumination On Mask) which applies the same concept as quadrupole illumination technique but gives many advantages over conventional techniques. This newly inserted mask gives drastic improvements in many areas such as DOF, resolution, low illumination intensity loss, and uniformity. In our experiments, we obtained best resolution of 0.28µm and 2.0µm DOF for 0.36µm feature sizes with i-line stepper, which is two times as wide as that of conventional illumination technique. We also obtained 0.22µm resolution and 2.0µm DOF for 0.28µm with 0.45NA KrF excimer laser stepper. For complex device patterns, more than 1.5 times wider DOF could be obtained compared to conventional illumination technique. From these results, we can conclude that 2nd generation of 64M DRAM with 0.3µm design rule can be printed with this technology combined with high NA (0.5) i-line steppers. With KrF excimer laser stepper, 256M DRAM can be printed with wide DOF.

This paper discusses methods and numerical simulations of one and two dimensional profilings for an arbitrary convex conducting target using the electromagnetic backscattering. The inversions for profile reconstructions are based upon the modified extended physical optics method (EPO). The modified EPO method assumes the modified physical optics current properly over the entire surface of conducting scatterers. First, the cross sectional area along a line of sight is reconstructed by performing iteratively the Fourier transform of the backscattering field in the frequency domain. Second, the two dimensional profile is reconstructed by synthesizing the above one dimensional results for several incident angles. Numerical simulation results of the target profiling are shown for spheroids and cone-spheroid.

Three dimensional (3-D) optics offers potential advantages to the massively-parallel systems over electronics from the view point of information transfer. The purpose of this paper is to survey some aspects of the 3-D optical interconnection technology for the future massively-parallel computing systems. At first, the state-of-art of the current optoelectronic array devices to build the interconnection networks are described, with emphasis on those based on the semiconductor technology. Next, the principles, basic architectures, several examples of the 3-D optical interconnection systems in neural networks and multiprocessor systems are described. Finally, the issues that are needed to be solved for putting such technology into practical use are summarized.

Recent progress in high-speed semiconductor devices and integrated circuits (ICs) has outpaced the conventional measuring and testing instruments. With advent of ultrashort-pulse laser technology, the electro-optic sampling (EOS) technique based on the Pockels effect has become the most promising solution way of overcoming the frequency limit, whose bandwidth is approaching a terahertz. This paper reviews recent progress on the research of the EOS technniques for measuring ultrahigh-speed electronic devices and ICs. It describes both the principle of the EOS and the key technologies used for noncontact probing of ICs. Internal-node measurements of state-of-the-art high-speed ICs are also presented.