Application of special gas in plasma etching

Application of special gas in plasma etching:

The advanced logic chip manufacturing process includes thousands of independent processes and USES nearly 100 different types of gas materials. As semiconductor feet more and more close to the limit of physics, in order to Moore's law to carry on the device to a smaller size, constantly have new material, new device structure and new technology is attractive to the integrated circuit manufacturing process, including the high dielectric constant material, sige carrier transmission reinforced material and metal grid materials; SiCoNiTM precleaning process and molecular beam epitaxial growth process, among which the type and quantity of plasma cleaning machine gas materials are also changing and increasing. In general, plasma cleaning machine gas materials according to the amount, production process of the degree of difficulty and safety into general gas and special gas two categories. General gases generally include oxygen (02), nitrogen (N2), hydrogen (H2), helium (He) and argon (Ar), etc. Special Gas refers to some unusual, difficult to produce and high-risk industrial synthetic gases used in a particular process. It can be pure Gas, high purity Gas or binary or multivariate mixed gases made of high purity elemental gases. They are mainly used in thin film, etching, doping, vapor deposition, diffusion and other processes. They are very important in the manufacturing process of semiconductor integrated circuit and often the decisive factor of key process steps. They are indispensable raw materials for the production of electronic industry.

Plasma cleaning machine semiconductor integrated circuit manufacturing process, all gases are required to have very high purity: general gas generally to control in the purity of more than 7 9 (≥99.99999%), special gases separate group is at least to control in the purity of more than 4 9 (>99.99%). The size of impurities in the gas particle to be controlled in the particle diameter of 0.1 m, the other need to control is oxygen. Water and other trace impurities, such as metals. Many special gases are toxic, corrosive, and spontaneous combustion (burning under certain conditions at room temperature). Therefore, the use and storage of special gases in the semiconductor OEM is different from ordinary industrial gases, which are delivered to different process stations in a safe and clean manner through an independent closed-loop distribution system.

1. Universal gas

Plasma cleaner Gas storage and transportation for gas suppliers is relatively simple. They are stored in large storage tanks at semiconductor foundries or in large pressurized tube trailers. These gases are transported to the super clean workshop through the bulk gas distribution system. The advantages of a batch gas distribution system for centralized control of gas storage and transport are: a reliable and stable gas supply, reduced sources of impurity particles, and reduced human interference in the daily gas supply. Common gases are usually classified into inert, reducing and oxidizing gases, as shown in Table 6.1.

Table 6.1 General gas classification and basic characteristics

2. Special gas

Plasma cleaning machine special gas refers to the supply of those relatively small and difficult to obtain gas. These gases are usually stronger activity, have higher toxic and corrosive, but by the dry they are certain integrated circuit manufacturing process steps must be material source, so need to be very careful to use these special gas, special gas often use independent pressurized cylinders to the semiconductor factories, generally stored in a separate storage room, and then the gas through a series of control, voltage regulator, switch and reaction chamber cleaning system connection into the process, such as plasma etching chamber. The storage room should also be equipped with a filtration system to detect gas purity and appropriate safety equipment, such as leak alarms and fire alarms.