Abstract: Provided are a semiconductor device in which a MOS transistor of SAC structure and a MOS transistor of silicide structure are are provided together, and a method of manufacturing the same. Each gate electrode (3) of gate structures (GT11 to GT13) is covered with an upper nitride film (4) and sidewall nitride film (5). Therefore, when an interlayer insulating film (10) being oxide film is selectively removed for forming contact holes (CH1 and CH2), the upper nitride film (4) and sidewall nitride film (5) are not removed, thereby preventing the gate electrode (3) from being exposed. Particularly, in the gate structures (GT11 and GT12), even when the contact hole (CH1) is dislocated to either side, no short-circuit is developed between a conductor layer (CL1) and the gate electrode (3). Thus, the gate structures (GT11 and GT12) can be disposed without being restricted by the alignment margin of the contact hole (CH1), and the distance between the gates can be reduced for attaining high integration.

Abstract: A semiconductor device including an interconnection structure having superior electrical characteristics and allowing higher speed of operation and lower power consumption even when miniaturized, manufacturing method thereof and a method of designing a semiconductor circuit used in the manufacturing method are provided. In the semiconductor device, a conductive region is formed on a main surface of a semiconductor substrate. A first interconnection layer is electrically connected to the conductive region, has a relatively short line length, and contains a material having relatively high electrical resistance. A first insulator is formed to surround the first interconnection layer and has a relatively low dielectric constant. A second interconnection layer is formed on the main surface of the semiconductor substrate, contains a material having low electrical resistance than the material contained in the first interconnection layer, and has longer line length than the first interconnection layer.

Abstract: A transistor which has a stable characteristic and which can prevent tilted ions from penetrating through a grain boundary to a channel region when ions are implanted at an angle so as to form impurity layers while a gate electrode is used as a mask. A gate electrode comprises a two-layer structure of a lower film and an upper film formed on a gate insulation film on the surface of a semiconductor substrate. The thickness of the lower film is made greater than the range of ions in the thicknesswise direction in the film when the ions are implanted to the sidewalls of the lower film.

Abstract: A method of manufacturing a semiconductor device which prevents a short circuit between a gate electrode and a diffusion layer region if a contact hole is shifted from its proper position. A material having an etch selectivity to an interlayer insulation film is formed over the gate electrode to serve as a cover against the formation of a contact hole. A material is not formed over an interconnect line which is required to be exposed to a contact hole.

Abstract: A first polysilicon film which contains phosphorus as an impurity is formed on a semiconductor substrate. A second polysilicon film which is higher in phosphorus concentration than the first polysilicon film is formed on the first polysilicon film. The second polysilicon film is anisotropically etched to expose a surface of the first polysilicon film. Thermal oxidation is then performed. A surface of the first polysilicon film and a surface of the second polysilicon film are oxidized according to their respective oxidization rates depending on their respective phosphorus concentrations. Thus, a semiconductor device in which the size of the gate electrode can be readily controlled and damage to the semiconductor substrate or the like can be suppressed, is obtained.