A representative integrated circuit includes a semiconductor integrated circuit such as a bipolar Ic whose substrate is a silicon single crystal and a MOS IC (metal oxide semiconductor stack). This section will discuss the role of insulating films in these semiconductor integrated circuits developed in the direction of ultra-high integration (VLSI) and ultra-high speed, and what will be presented in the future along with the development of super I.SI. Insulation film technology, etc.
A semiconductor integrated circuit has a large number of devices (up to 10 s devices/chips), such as bipolar transistors and MOS transistors, formed on a single crystal substrate. In order to realize their respective functions, they are interconnected by wiring.
In such a semiconductor integrated circuit, the use of the insulating film can be classified as follows depending on its action and required characteristics and the conditions proposed in the film forming process:
1 For example, a gate insulating film in a MOS transistor utilizes an insulating film/semiconductor interface phenomenon, whereby the function of an active device can be realized;
2 The contact with the device, such as the SiO 2 film covering the surface of the crystal, can make the crystal surface chemical and electrical properties inactive, so as to achieve the purpose of stabilizing the device characteristics;
3 If the SiO2 film is formed on the crystal surface between the devices, the insulating film (field oxide film) is made to electrically isolate the devices from each other and is interconnected on the surface.
4 Interlayer insulation film for electrical insulation between wiring layers;
5 for the purpose of protecting the device from the physical and chemical point of view, an insulating film as a surface coating film is formed on the surface of the integrated circuit;
6 It is used in integrated circuit processes and is used in masks for local processes such as impurity diffusion, etching, and substrate surface oxidation.