| Popis: |
The growing rates of microchip world production during the last two decades exceed essentially the corresponding indexes of any others production branches. Between 1997 and 2003 the consumer and communication electronics sales have grown from USD 744 billion to about USD 165 trillion. The present-day electronics is based on a silicon technology and such a state will be conserve at least during the nearest ten years. The low temperature plasma facilities so called plasma reactors or glow discharge reactors, play an important role in technological processes of chip production. Such reactors are widely used for etching and deposition of semiconductor films, for taking off photoresist and some other operations. Very often they enter the complex cluster equipment for making chips. Some characteristic schemes of these glow discharge reactors are presented in Fig. 1. The typical reactor consists of two parallel plate electrodes forming an axisymmetrical cylinder chamber, in which the high-frequency discharge is appeared. The processing wafer is placed on one of the electrodes. The originally inert feed gas enters the discharge zone where an active etchant species is produced by the electron impact dissociation. The active species transfers to the wafer and reacts with it forming the volatile products. The unreacted feed gas and the products of physical-chemical processes and reactions are pumped outwards from the reactor. From the presented schemes one can see that these reactors are not very complicated and expensive apparatus. But yet in 1995 a world volume of sales of the reactors have made up USD 2 billion and it keeps on growing. This numeral can give us a rough idea about the quantity of operative reactors in modern industry. Despite of the relative simple construction the etching process in a reactor is a very complicative one. For silicon wafer operating the complex molecular gases such as CF4, SF6 and their mixtures with oxygen O2 and hydrogen H2 are used. Under a microwave discharge and ion current in etching chamber a reacting medium appears which is characterized by simultaneously proceeding processes of ionization, dissociation, heat and mass transfer with complex chemical reactions. A similar processes take place on the surfaces of the chamber and wafer under operating. The quality and manufacturing rate of producing chips depend strongly on a large number of process variables in a reactor including parent gas composition, pressure, temperature, frequency and power of a discharge, flow rate and configuration, etc. Because of numerous |
