As one of the most advanced and precise equipment in the world, a photolithography scanner is able to fabricate nanometer-scale devices on a chip. To realize such a small dimension, the optical system is the fundamental, but the mechanical system often becomes the bottleneck. In the photolithography, the exposure is a dynamic process. The accuracy and precision of the movement are determined by the mechanical system, which is even more difficult to control compared with the optical system. In the mechanical system, there are four crucial components: the reticle and wafer stages, the linear motor, the metrology system, and the control system. They work together to secure the reticle and substrate locating at the correct position, which determines the overlay and alignment performance in the lithography. In this paper, the principles of these components are reviewed, and the development history of the mechanical system is introduced.
Advanced transmission electron microscopy combined with in situ techniques provides powerful ability to characterize the dynamic behaviors of phase transitions, composition changes and potential variations in the nanomaterials and devices under external electric field. In this paper, we review some important progress, in this field, of the explanation of structural transition path caused by the Joule heating in C60 nanowhikers, the clarification of electron storage position in charge trapping memory and the direct evidences of the oxygen vacancy channel and the conductive filament formation in resistive random access memory. These studies could improve an understanding of the basic mechanism of nanomaterial and device performance, and also demonstrate the diversity of the functions of transmission electron microscopy in microelectronic field.
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