A method for manufacturing a semiconductor device includes: forming a first and second layers not firmly adhering to each other over a substrate; forming a first semiconductor element layer and a first insulating layer over the second layer; forming a hole reaching the first layer in the first insulating layer; oxidizing the first layer exposed at a bottom of the hole; forming a wiring electrically connected to the first semiconductor element layer over the first insulating layer and in the hole; and separating the first layer and the substrate from the second layer and the first semiconductor element layer and expose the wiring. Further, another method includes providing an anisotropic conductive adhesive between a second semiconductor element layer separated through a manufacturing process similar to the above and the wiring, whereby the first and second semiconductor element layers are electrically connected through the anisotropic conductive adhesive and the wiring.