Browsing by Author "Kido, Motoi"
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Item Interferometric Phase Shift Technique for High Resolution Deep UV Microlithography(SPIE, 1994-09-01) Tittel, Frank K.; Cavallaro, Joseph R.; Kido, Motoi; Smayling, Michael C.; Szabo, Gabor; Wilson, William L.; Center for Multimedia CommunicationA new phase shifting technique based on interferometry has been developed which is especially suited for deep-UV microlithography. Using only a single layer chromium mask, with no additional phase shift elements, significant resolution and contrast enhancement over conventional transmission lithography can be achieved. Both computer simulations, as well as experiments using a CCD camera and UV photoresist confirm the capabilities of this new approach. Using a relatively simple experimental setup and an illumination wavelength of 355 nm, lines with feature sizes as find as 0.3 um were achieved.Item A New Interferometric Phase-Shifting Technique for Sub-half-micron Laser Microlithography(SPIE, 1995-02-01) Erdelyi, Miklos; Sengupta, Chaitali; Bor, Zsolt; Cavallaro, Joseph R.; Kido, Motoi; Smayling, Michael C.; Tittel, Frank K.; Wilson, William L.; Szabo, Gabor; Center for Multimedia CommunicationThis paper reports recent progress in achieving sub-half-micron feature sizes with UV laser illumination based on a novel interferometric phase shifting (IPS) technique. In the IPS arrangement, the intensity and amount of phase shift of the shifted beam can be controlled continuously and independently using the same mask. Consequently the method can be considered as a convenient general testbed for practical phase shifting concepts such as strong, weak and attenuated phase shifting. Recent measurements of the lithographic performance of a new concept are reported where phase shifting is combined with off-axis illumination. Experimental as well as simulation data are used to demonstrate this new method. A lithography simulator, Depict from Technology Modeling Associates, Inc. and a related Integrated CAD Framework which is being developed at Rice University was used to simulate and evaluate the performance of the IPS scheme.Item A New Phase Shifting Method for High Resolution Microlithography(SME Press, 1994-01-01) Kido, Motoi; Cavallaro, Joseph R.; Szabo, Gabor; Wilson, William L.; Tittel, Frank K.; Center for Multimedia CommunicationOne of the most promising lithographic technique for the future designs of DRAMs is the phase-shifting mask technique. Conventional phase shifting-masks, however, are difficult to fabricate as they require regions of different optical thickness. We present a new phase shifting technique that does not use any phase shifting materials. A special interferometer and a mask that has both transmitting areas and reflective areas accomplish the required phase-shift at the image plane. Using this technique we have demonstrated phase shifting effects using a CCD camera. We also present the results of a computer simulation for the critical resolution of this new method in comparison with the conventional phase shifting approach.Item A New Phase Shifting Technique for Deep UV Excimer Laser Based Lithography(SPIE, 1995-02-01) Bor, Zsolt; Cavallaro, Joseph R.; Erdelyi, Miklos; Kido, Motoi; Sengupta, Chaitali; Smayling, Michael; Szabo, Gabor; Tittel, Frank; Wilson, William; Center for Multimedia CommunicationThis paper reports simulation and experimental details of a novel phase shifting technique based o laser interferometry. Phase shifting is one of the most promising techniques for the fabrication of high density DRAM's. In recent years many kinds of phase shifting methods have been proposed to extend the resolution limit and contrast of image patterns. These techniques however, have several problems that result from the phase shift elements on the mask, especially when applied to UV excimer laser illumination. A new technique will be described that is based on a one-layered reticle which is used as both a reflective and transmissive mask, irradiated from both the front and the back sides. A combination of both off-axis illumination, as well as phase shift are used in this method. Both the relative path length of the two beams as well as their amplitude can be manipulated in such a way that near 100% contrast can be achieved in the final image. Experimental as well as simulation data are used to demonstrate this new method.Item Submicron Optical Lithography Based on a New Interferometric Phase Shifting Technique(Japanese Journal of Applied Physics, 1995-08-01) Kido, Motoi; Szabo, Gabor; Cavallaro, Joseph R.; Wilson, William L.; Smayling, Michael C.; Tittel, Frank K.; Center for Multimedia CommunicationThis paper reports the computer simulation and experimental demonstration of a new phase shifting technique based on interferometry that is especially suited for deep ultraviolet (UV) microlithography. Significant resolution and contrast enhancement can be achieved using a chrome binary mask. Image analysis based on charge coupled device (CCD) detection and patterns recorded in UV photoresist has been used to study the capabilities of this new approach. Lines with a feature size as fine as 0.3 µm have been demonstrated using 355 nm illumination.