US 2003/0153154 A1 · Manufacturing method of semiconductor device

Abstract

A manufacturing method of this invention has an ion-implantation process for threshold voltage adjustment of an MOS transistor, including a process to form a first well of an opposite conductivity type in a substrate of one conductivity type, to form a second well of the opposite conductivity type having higher impurity concentration than that in the first well, under a region where a thin gate insulation film is formed, to form gate insulation films on the first well and the second well, each having a different thickness, to ion-implant first impurities of the one conductivity type into the wells of the opposite conductivity type under the condition that the impurities penetrate the gate insulation films of different thicknesses and to ion-implant second impurities of the one conductivity type into the second well of the opposite conductivity type under the condition that the second impurities penetrate the thin gate insulation film but do not penetrate the thick gate insulation film. Thus the ion-implantation process for the threshold voltage adjustment of a semiconductor device having gate insulation films of different thicknesses can be rationalized with this invention.

Claims6

Dependent claims

A manufacturing method of a semiconductor device comprising:

providing a semiconductor substrate of a first conductivity type;
forming a first well region of a second conductivity type in the semiconductor substrate;
forming a second well region of the second conductivity type having an impurity concentration higher than an impurity concentration of the first well region;
forming a first gate insulation film on the first well region;
forming a second gate insulation film thinner than the first gate insulation film on the second well region;
ion-implanting first impurity ions of the first conductivity type into the substrate so that the first impurity ions reach the first and second well regions through the first and second gate insulating films;
and
ion-implanting second impurity ions of the first conductivity type into the substrate so that the second impurity ions reach the second well region through the second gate insulating film and do not reach the first well region through the first gate insulating film.

5 more elements

Dependencies are inferred from the claim text.

Manufacturing method of semiconductor device

Life of this patent

Manufacturing method of semiconductor device

Life of this patent

Abstract

Claims6