Typical integrated circuits include semiconductor integrated circuits such as bipolar Ic whose substrate is silicon single crystal and MOS IC (metal-oxide-semiconductor stack). In this section, the role of insulating films in these semiconductor integrated circuits developed in the direction of ultra-high integration (VLSI) and ultra-high speed will be discussed, and what will be proposed in the future with the development of ultra-I.SI Insulation film technology.
Semiconductor integrated circuits are formed on a single crystal substrate with very many (up to 10 s elements / chips) bipolar transistors and MOS transistors. In order to perform their respective functions, they are interconnected with wiring.
In such semiconductor integrated circuits, the use of insulating films can be classified according to their functions and required characteristics, as well as the conditions proposed in the film formation process, as follows:
① For example, the gate insulating film in a MOS transistor uses the insulating film / semiconductor interface phenomenon, thereby achieving the function of an active device;
② In contact with the device, such as a SiOz film covering the surface of the crystal, the chemical and electrical properties of the crystal surface can be made inactive, thereby achieving the purpose of stabilizing the characteristics of the device;
③ If the SiOz film is formed on the crystal surface between the devices, the insulating film (field oxide film) for the purpose of electrically isolating the devices and wiring each other on the surface;
④ interlayer insulation film for the purpose of electrical insulation between wiring layers;
⑤ An insulating film formed on the surface of an integrated circuit as a surface covering film for the purpose of protecting the device from a physical and chemical perspective;
⑥ It is used in integrated circuit technology, and is used as a mask for local processes such as impurity diffusion, corrosion, and substrate surface oxidation.