Patent ID: 6504644
Filing Date: 2003-01-07
Classification: B23K,B41J,G02B,G03F,G09G,H04N

Abstract:
An apparatus for creating a pattern on a workpiece sensitive to light radiation, such as a photomask, a display panel or a microoptical device, comprising:a source for emitting light in the wavelength range from EUV to IR, a spatial light modulator (SLM) having a multitude of modulating elements (pixels), adapted to be illuminated by said radiation, a projection system creating an image of the modulator on the workpiece, an electronic data processing and delivery system receiving a digital description of the pattern to be written, converting said pattern to modulator signals, and feeding said signals to the modulator, a precision mechanical system for positioning said workpiece and/or projection system relative to each other, an electronic control system controlling the position of the workpiece, the feeding of the signals to the modulator and the intensity of the radiation, so that said pattern is printed on the workpiece, where the drive signals and the modulating elements are adapted to create a number of modulation states larger than two, where intermediate modulation states are used for pixels along edges of pattern features, and the design of the modulating elements and the exposure method are adapted to create, for differently placed and/or differently oriented edges in the pattern, a symmetry in an aperture stop of the projection system.