Resistless mask structuring using an ion multi-beam projection pattern generator

Line edge roughness (LER) and substrate resist interaction of chemically amplified resists (CAR) might be limitations for future mask making. An alternative solution could be the direct patterning of a thin hard mask on top of an absorber using a multiple ion beam pattern generator. Goal of this work was to assess a resistless hard mask structuring by direct patterning and a subsequent transfer into chrome by a dry etch process. Hard mask structuring has been done on the IMS Nanofabrication proof of concept tool which is designed for 40,000 multi-beam operations. For comparison to the resistless approach, a resist based stack patterning has been set up. Hard mask opening and subsequent chrome etching have been accomplished in a state of the art mask etcher. The assessment of both process schemes has been done in terms of feature profile and resolution capability. Finally, throughput estimation for a future production tool, operating with precursor gases and 1.000.000 ion beams has been calculated.