Patent ID: 6949437

Claim:
A manufacturing method of a semiconductor device which is formed with a bipolar transistor being composed by including a base, an emitter and a collector on a semiconductor substrate, comprising the steps of: forming a multilayer film on said semiconductor substrate, and forming an opening, which is opened on said base and said emitter, in the multilayer film; forming on an entire surface a compound semiconductor film which contains silicon and an other semiconductor element, and has a composition with a high content of silicon in an upper layer region and a lower layer region, and a high content of the other semiconductor element in an intermediate layer region; performing anisotropic dry etching for the compound semiconductor film so as to reach a certain height of the opening, but performing no isotropic etching, wherein the anisotropic dry etching is performed for the compound semiconductor film in a high vacuum state; and further comprising the step of: performing quasi-anisotropic dry etching for the compound semiconductor film in a low vacuum state after the anisotropic dry etching is performed for the compound semiconductor film in the high vacuum state.