Nanopatterning of diblock copolymer directed self-assembly lithography with wet development

We report wet development technique for directed self-assembly lithography pattern. For typical diblock copolymer, poly (styrene-block-methyl methacrylate) (PS-b-PMMA), the PMMA area is removed by O-2 plasma. However, O-2 plasma attack also etches off PS area simultaneously. As a result, the thickness of residual PS pattern is thinner and it causes degradation of PS mask performance. PS thickness loss in the device integration is not desirable as etching mask role. In this work, we applied wet development technique which could be higher selectivity to keep PS film thickness after pattern formation. Especially, we propose the method using low pressure mercury lamp and conventional TMAH (2.38%) as developer. It is expected to accomplish pattern formation in one track with coating, baking, exposure and development.