VARIABLE SHAPED ELECTRON-BEAM LITHOGRAPHY APPLICATION TO SUBWAVELENGTH AND COMPUTER-GENERATED DIFFRACTIVE OPTICS FABRICATION

Electron-beam lithography for generation of diffractive optical elemen ts topology is examined. The formula for the estimation of exposure da ta volume for variable shaped electron-beam lithography is presented a s a function of diffractive optical element parameters and approximati on accuracy. Diffractive optical elements with a subwavelength feature size were manufactured. These elements act as optical elements with a n artificial refractive index. A Fresnel zone plate with an artificial phase retardation has been manufactured. Based on the proximity funct ion measured for the actual exposure conditions, the proximity correct ion has been provided and undistorted structures have been fabricated. Experimental results are presented on computer generated optical elem ents for industrial applications. A computer generated lens which focu ses radiation into a ring has been fabricated. A photomask set was man ufactured for a reflecting optical element which focuses a high power CO2 laser beam to two points with parameters required for laser weldin g. (C) 1995 American Vacuum Society.