A semiconductor device and a method for manufacturing a semiconductor device are provided. The semiconductor device includes a substrate, a gate stack, a gate spacer, a conductive feature, and a conductive cap. The substrate has a source/drain region. The gate stack is on the substrate. The gate spacer is alongside the gate stack. The conductive feature is on the source/drain region. The conductive cap is on the conductive feature and has a top in a position lower than a top of the gate spacer.