Blazed reflection micro-Fresnel lenses fabricated by electron-beam writing and dry development

Abstract

The microfabrication of a blazed reflection micro-Fresnel lens (RMFL) using electron-beam writing and dry development is proposed and demonstrated. The electron-beam-written resist film made of polymethyl isopropenyl ketone and an aromatic azido compound achieved the blazed structure by O(2) plasma development. The surface roughness of the RMFL was improved without the bridge and scum. The fabricated RMFL exhibited the diffraction-limited characteristics. A high efficiency of 71% was obtained at a period of 10 microm. The margin for the electron-beam writing condition to achieve high efficiency was much broader than in the conventional process. This process would be effective for the fabrication of blazed RMFL's and other grating components.