Patent ID: 6100124
Filing Date: 2000-08-08
Classification: H01L

Abstract:
A method for manufacturing a BiCMOS semiconductor device including bipolar transistors and MOS transistors, including the steps of:selectively forming a device isolation insulator film on a semiconductor substrate of a first conductivity type;selectively forming in said semiconductor substrate a region of a second conductivity type opposite to the first conductivity type and a collector leading-out region of a bipolar transistor;forming at least one well for a MOS transistor in said semiconductor substrate;forming an insulating film on the whole surface of said semiconductor substrate including said well, and also forming a first polysilicon film on said insulating film;selectively removing all of said first polysilicon film in a bipolar transistor formation area without substantially removing said insulating film in the bipolar transistor formation area and the first polysilicon film in a MOS transistor formation area;forming a first region of said second conductivity type in said semiconductor substrate in said bipolar transistor formation area;forming a second region of said first conductivity type in said first region of said second conductivity type;forming a second polysilicon film on the whole surface of said semiconductor substrate including said first polysilicon film and said insulating film above said second region of said first conductivity type;selectively removing said second polysilicon film and said insulating film above said second region of said first conductivity type, to form an opening exposing a predetermined area of said second region of said first conductivity type;forming a third polysilicon film including impurity of said second conductivity type, on the whole surface of said semiconductor substrate including said second polysilicon film and said opening; andselectively removing said first, second and third polysilicon films so that said first, second and third polysilicon films are selectively left above said well, and said second and third polysilicon films are selectively left above said second region of said first conductivity type.