METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE

摘要

To provide a semiconductor device having mix-loaded therein a nonvolatile memory cell and a field effect transistor at a reduced cost. A method of manufacturing a semiconductor device includes pattering a conductor film by using an additional mask that covers a gate electrode formation region of a memory formation region and exposes a main circuit formation region (field effect transistor formation region) and thereby forming a gate electrode of a nonvolatile memory cell in the memory formation region and then forming an n− type semiconductor region of the nonvolatile memory cell in a semiconductor substrate by ion implantation using the above-mentioned additional mask without changing it to another one.

主权项

1. A method of manufacturing a semiconductor device comprising:
a nonvolatile memory cell formed in a first region of a semiconductor substrate; and a field effect transistor formed in a second region of the semiconductor substrate, the nonvolatile memory cell including: a well formed in the semiconductor substrate; a source region formed in the well; a drain region formed in the well, separated from the source region; a channel region sandwiched between the source region and the drain region; a first insulating film formed over the channel region; a charge storage film formed over the first insulating film; a second insulating film formed over the change storage film; and a first gate electrode formed over the second insulating film, the source region and the drain region each including: a first semiconductor region having a first impurity concentration; and a second semiconductor region having a concentration higher than the first impurity concentration, the method comprising the steps of: (a) forming an insulating film over the semiconductor substrate; (b) forming a first conductor film over the insulating film; (c) removing the first conductor film and the insulating film from the first region by using a first mask that exposes the first region and covers the second region; (d) after the step (c), forming the well in the first region by ion implantation using the first mask; (e) after the step (d), forming the first insulating film over the semiconductor substrate and the first conductor film; (f) forming the charge storage film over the first insulating film; (g) forming the second insulating film over the charge storage film; (h) forming a second conductor film over the second insulating film; (i) patterning the second conductor film by using a second mask that covers a first gate electrode formation portion of the first region and exposes the second region and thereby forming the first gate electrode in the first region; (j) after the step (i), forming the first semiconductor region in the semiconductor substrate by ion implantation using the second mask; and (k) after the step (j), patterning the first conductor film by using a third mask that covers a second gate electrode formation region of the second region and covers the first region and thereby forming a second gate electrode of the field effect transistor in the second region.