Stability of DRAM-devices with respect to 75 keV helium ion beam irradiation as required for ion projection lithography of critical layers

Abstract

Abstract Ion projection lithography (IPL) is one of the next generation lithography techniques, targeting the 50-nm node and below. During the last year tool, mask and process development have made major advances. A resolution of 50 nm has been achieved locally, 75 nm over a field size of 12.5×12.5 mm 2 . Compatibility of ion projection lithography with a standard semiconductor process has not been proven so far. Possible device damage is still seen as a critical issue. Therefore experimental investigation of the influence of ion beam irradiation on the functionality of state-of-the-art chips is necessary. We carried out the experiment with a state-of-the-art DRAM product processed at a high volume production site. The experiment demonstrates that 75 keV He + ion beam exposure with ion doses as used for ion projection lithography would cause no detrimental damage. Thus IPL is suitable for semiconductor device fabrication.