GAP CONTROL IN THE FABRICATION OF QUANTUM-EFFECT DEVICES USING X-RAY NANOLITHOGRAPHY

We report on recent advances in the fabrication of quantum-effect devi ces using x-ray nanolithography. A novel scheme for gap control during the mask replication process was developed that uses capacitance sens ing in a feedback loop. The capacitance between two masks is measured and held constant through control of the pressure between them. This s cheme can be used to maintain the masks at a gap as small as 1 mum, th us reducing penumbra and diffraction. This capacitive feedback method, used in mask-to-mask replication can, in principle, also be used for mask-to-substrate exposures and is thus an additional element in an x- ray nanolithography technology for sub-70 nm features.