Patent ID: 6337242
Filing Date: 2002-01-08
Classification: H01L

Abstract:
A method for fabricating a mixed signal semiconductor device, comprising:a step for dividing a semiconductor substrate into an active region and a field region; a step for forming a gate oxide film on an upper surface of the semiconductor substrate; a step for forming a first polysilicon film on an upper surface of the gate oxide film; a step for forming a silicon nitride film on an upper surface of the first polysilicon film; a step for patterning the silicon nitride film and exposing a first polysilicon corresponding to the upper portion of the field region; a step for implanting an impurity ion into the first polysilicon film; a step for forming a capacitor oxide film on an upper and lateral surface of the patterned silicon nitride film and on an upper surface of the exposed first polysilicon film; a step for forming a second polysilicon film on an upper surface of the capacitor oxide film; a step for removing the second polysilicon film and the capacitor oxide film formed on the upper surface of the silicon nitride film and planerizing the remaining second polysilicon film, capacitor oxide film and silicon nitride film; a step for patterning the silicon nitride film, first polysilicon film and second polysilicon film; a step for etching the silicon nitride film; and a step for forming a LDD(Lightly Doped Drain) in the active region.