Abstract: An apparatus manufactures a semiconductor device. The apparatus includes a film formation device, a first detector and a second detector. The film formation device forms an embedded layer for embedding a trench disposed at a substrate in the semiconductor device. The first detector detects a state of a first region of the substrate where the trench is disposed. The second detector detects a state of a second region of the substrate, the second region disposed outside of the first region. The film formation device ends film formation of the embedded layer, based on a condition that difference between a first detection result corresponding to the state of the first region and a second detection result corresponding to the state of the second region is smaller than or equal to a threshold value.