Advanced EUV negative tone resist and underlayer approaches exhibiting sub-20nm half-pitch resolution

The RLS trade-off of EUV resists has been a major technical issue for high-volume manufacturing using EUVL. Significant attempts to develop of chemically-amplified resists, metal-containing resists, and a variety of other material classes have been made to obtain low LER at high resolution (R) and at a reasonable sensitivity (S). Previously, we have developed and reported work on silanol-containing polyhydrogensilsesquioxane resins and their use as negative tone resists. The developed silanol-containing polymer resists have demonstrated enhanced EUV sensitivity compared to traditional hydrogen silsesquioxane resins, and at the same time maintaining excellent etch properties. The resist may enable a bilayer stack technology in EUVL. Herein we report novel functionalized polyhydrogensilsesquioxane polymers and their use as negative tone resists. These materials exhibit improved LER/LWR and reasonably good EUV sensitivity. In best cases, data suggests no residues or bridging in the non-exposed areas. The optimized resist exhibits sub-20nm halfpitch resolution, low LER (2-3nm), and reasonable sensitivity (82.5 mJ/cm²). In addition, we also investigated the effect of three organic underlayers for EUV patterning and compared with the silicon substrate.