The present invention provides a semiconductor device structure and an
easy-to-use method for manufacturing thereof enabling to suppress wafer
contamination and to form the semiconductor device superior in control
and uniformity of the film thickness in the semiconductor device
including plural kinds of transistors provided with a gate insulator film
with different film thickness.According to the method, plural kinds of
transistors with gate insulator films having different electric film
thickness are formed in the steps of forming an insulating film layer
including a lamination structure of at least first insulating film 104
constituted of first high-dielectric insulating material and second
insulating film 103 constituted of second high-dielectric insulating
material on the same silicon substrate 101, selectively etching and
removing the upper insulating film 103 on the part of region 105 by use
of mask 107 and utilizing multi-oxide process while reducing leak
electric current.