Multi-beam lithography is considered a promising fabrication technology for future node mask making. Due to rising design complexity and therefore increasing pattern writing times the multi-beam approach has distinguished throughput advantages compared to state of the art variable shaped beam pattern generators. A key component of a projection multi-beam writing tool is the programmable blanking-plate for generating the desired pattern geometry on the mask substrate. In our case a highly parallel charged particle beam illuminates a Si aperture-plate which shapes and generates many thousand individual spot beams. These beams pass through a blanking-plate with integrated CMOS electronics for demultiplexing the writing data. The blanking-plate is equipped with blanking and ground electrodes placed around the apertures switching the beams "on" or "off", dependent on the desired pattern. The beam array is demagnified by a 200x reduction optics and the exposure of the mask substrate is done in stripes by a continuous moving stage [1,2]. Cross talk between adjacent beams in the blanking-plate has to be avoided to ensure adequate pattern fidelity and line edge roughness on the mask substrate. One solution is the insertion of a 3D Si aperture-plate in proximity to the blanking- plate shielding the blanking electrodes from each other during operation. We developed and characterized a new process flow for the fabrication of these 3D Si aperture-plates for the case of 43 thousand beams in parallel and will present and discuss the cross talk results for blanking-plates combined with standard 2D and new 3D Si aperture-plates.

Date Published: 23 September 2009
PDF: 11 pages
Proc. SPIE 7488, Photomask Technology 2009, 74883C (23 September 2009);

Published in SPIE Proceedings Vol. 7488:
Photomask Technology 2009
Larry S. Zurbrick; M. Warren Montgomery, Editor(s)