A method of manufacturing a semiconductor structure includes forming an active region having a first portion which is doped. The method further includes forming a first silicide layer over and electrically coupled to the first portion of the active region. The method further includes forming a second silicide layer under and electrically coupled to the first portion of the active region. The method further includes forming a first metal-to-drain/source (MD) contact structure over and electrically coupled to the first silicide layer. The method further includes forming a first via-to-MD (VD) structure over and electrically coupled to the MD contact structure. The method further includes forming a buried via-to-source/drain (BVD) structure under and electrically coupled to the second silicide layer.