Laying the Groundwork for High NA EUV Patterning

Extreme Ultraviolet Lithography (EUVL) has replaced DUV immersion lithography in high volume production at the leading-edge node and 5-nm EUV powered consumer devices are now available. This achievement marks an important milestone after nearly four decades of development of EUV. Despite this tremendous achievement, much work remains to be done to ensure the extendibility of the technology which depends on the development of high numerical aperture (NA ≥ 0.5) systems and processes. High NA significantly stresses several current challenges and brings with it fundamentally new challenges. The most significant new challenge arises from angular bandwidth limitations of the mask multilayer requiring the use of anamorphic optics, or new multilayer material systems as well as polarization concerns that have never been an issue before for EUV owing to the relatively small angles involved. The most significant existing challenge being pushed to a fundamentally new regime with high NA revolves around stochastics in photoresist materials and exposure processes. As we approach the atomic scale, the quantized nature of light, electrons, and materials is becoming a very significant effect in ultimate performance of the process. Addressing these challenges will require the understanding and control of materials and their interaction with photons and electrons at the atomic scale. In this presentation, I will provide an overview of the high NA research facility at Lawrence Berkeley National Laboratory and highlight recent results.