| 摘要 |
PURPOSE:To improve the integration of a bipolar element by etching by self- aligning the part of the prescribed distance from an element isolating region in an insulating film of an Si substrate. CONSTITUTION:A buried layer 2 and an Si epitaxial layer 3 are superposed on an Si substrate 1, an SiO2 layer 4 and an Si3N4 layer 5 are formed as masks. The layer 2 is subjected to reactive sputter etching to form a slot 6 through the layer 2. A channel stopper is provided in the bottom of the slot to cover the bottom with an SiO2 layer 7. The film 5 is removed, ions are implanted to form a base layer 8, and Si3N4 layer 9, a polysilicon film 10 and an Si3N4 film 11 are superposed, and the slot 6 is buried with polysilicon 12. Mo 13 is then covered, heat treated to form an MoSi2 film 14, an overhang 15 is formed over a base 8, and unreacted Mo is removed. The film 11 is etched with the MoSi2 mask, the mask is then removed, the films 10, 12 are oxidized, and an SiO2 film is formed. The polysilicon 10 is etched by the mask 16, SiO2 films 17, 18 are covered. Subsequently, the films 9, 16, 4 are etched in this order. Then, a base connecting window 19 is obtained within the prescribed near distance from the slot 6, the overhang 15 is controlled to control the size of the window, and a bipolar transistor is formed thereafter in high integration. |
