Abstract: A plug fabricating method, capable of fabricating a minute plug with a good configuration, reducing scum and simplifying the plug fabricating process, makes an inter-layer insulating film on a Si substrate and forms a contact hole in the inter-layer insulating film. A direct contact layer in form of a Ti/TiN film is formed on the inter-insulating, film to also cover the bottom surface and the side wall of the contact hole. After a W film is formed on the entire surface in a deposition chamber, ClF3 gas exhibiting a strong reducing property is supplied as an etching gas into the deposition chamber, and the W film and the direct contact layer are partly removed an by etch-back processing using gas etching by the ClF3 gas. As a result, a contact plug of W deposited on the direct contact layer as the base is formed inside the contact hole.