A semiconductor device manufacturing method includes forming a gate dielectric layer surrounding first semiconductor patterns and second semiconductor patterns; forming a first organic pattern covering the second semiconductor patterns; forming a sacrificial pattern interposed between the first semiconductor patterns and exposing both side surfaces of the first semiconductor patterns, and a conductive pattern surrounding the second semiconductor patterns and disposed between the first organic pattern and the second semiconductor patterns; forming a second organic pattern covering the first semiconductor patterns, the gate dielectric layer, the sacrificial pattern, and the first organic pattern; and forming a cross-linking layer interposed between the first organic material pattern and the second organic material pattern.