Neutral hard mask and its application to graphoepitaxy-based directed self-assembly (DSA) patterning

摘要

A material stack is formed on the surface of a semiconductor substrate. The top layer of the material stack comprises at least an organic planarization layer. A neutral hard mask layer is formed on the top of the organic planarization layer. The neutral hard mask layer is neutral to the block copolymers used for direct self-assembly. A plurality of template etch stacks are then formed on top of the neutral hard mask layer. After formation of the template etch stacks, neutrality recovery is performed on the neutral hard mask layer and the top portions of the template etch stacks, the vertical sidewalls of the template etch stacks being substantially unaffected by the neutrality recovery. A template for DSA is thus obtained.