Fabrication method of semiconductor device
View Patent ↗Provided is a fabrication method of a semiconductor device having an improved production yield. An insulating film for forming sidewall insulating films of a gate electrode is deposited on the main surface of a semiconductor wafer and then, subjected to the treatment for equalizing the film thickness distribution. In this treatment, the semiconductor wafer is fixed onto a spin stage of an etching apparatus and rotated; and an etchant is supplied from an etchant nozzle to the main surface of the rotating semiconductor wafer while moving thereabove the etchant nozzle from the peripheral side to the central side on the main surface of the semiconductor wafer. The moving speed of the etchant nozzle is controlled, depending on the thickness distribution of the insulating film and is made lower in a region where a change rate of the thickness of the insulating film in a radial direction of the semiconductor wafer is large than in a region where the change rate is small.
1. A fabrication method of a semiconductor device, comprising the steps of:
(a) preparing a semiconductor wafer;
(b) forming a first conductive film for gate electrode over the main surface of the semiconductor wafer;
(c) forming a first insulating film for the first conductive film;
(d) patterning the first insulating film;
(e) after the step (d), correcting the size of the first insulating film pattern over the semiconductor wafer; and
(f) after the step (e), etching the first conductive film with the first insulating film pattern as an etching mask to form the gate electrode,
wherein in the step (e),
an etchant for etching the first insulating film pattern is supplied to the main surface of the semiconductor wafer from an etchant supply means while rotating the semiconductor wafer and moving thereabove the etchant supply means from the peripheral side to the central side of the main surface of the semiconductor wafer, and
the moving speed of the etchant supply means is changed between the peripheral side and central side of the semiconductor wafer.
2. A fabrication method of a semiconductor device according to claim 1 ,
wherein in the step (e), a size of the first insulating film pattern is reduced and a reduction amount of the size of the first insulating film pattern is greater on the peripheral side of the semiconductor wafer than on the central side thereof.
3. A fabrication method of a semiconductor device according to claim 2 ,
wherein in the step (e), the moving speed of the etchant supply means is controlled, depending on the distribution, over the semiconductor wafer, of a taper amount of the gate electrode generated during the step (f).