Fluid/MC Investigation On Pulse Modulated RF Capacitively Coupled H₂ Discharge

Nowadays we are familiar with microelectronics products and they have become an important part of our lives. At the same time, the progress of semiconductor industry depends on the progress of microelectronics technology. In the field of semiconductor industry, low temperature plasma technology is very important, especially in the field of manufacturing large scale integrated circuit.Thin film deposition and plasma etching are the most widely used low temperature plasma technologies. Among many thin film deposition methods, plasma enhanced chemical vapor deposition (PECVD) is most popular. PECVD has many advantages, such as low working temperature and good uniformity of film. Capacitively couple plasma (CCP) is often employed in PECVD which has simple discharge chamber structure and can produce large area and uniform plasma. In the PECVD processes, SiH4 takes small amounts in H2SiH4 mixtures, we just focus on hydrogen plasmas in this work. Fluid Monte-Carlo (Fluid/MC) hybrid model is applied to research pulse modulated radio frequency CCP H2 discharge. Pulsed plasma can provide two more parameters, including pulse duty cycle and pulse frequency. Adjusting these two parameters can improve the plasma process. Higher plasma density can be obtained on the condition of low pulse duty cycle comparing with continuous waves. Meanwhile charge particles'energy drop rapidly during power-off period, which can reduce plate damages during deposition. The negative ions escape to electrodes during power-off period, which is beneficial for materials deposition. In addition, some deposition precursors spread to the electrode during power-off period, which can prolong the time for deposition before the next power-on period. The arrangement of this article is listed below:The concept of low temperature plasma, low temperature plasma sources and applications, especially in the field of microelectronics technology industry are introduced in chapter 1. Meanwhile we mainly focus on introducing the basic principle and advantages of pulse modulation. In addition, the research progress of pulse modulated rf plasma in two aspects are introduced, including experimental and numerical simulation.We introduce several numerical simulation models, and mainly focus on the fluid/MC hybrid model. The plasma discharge chamber structure and the main chemical reactions of H2 are also introduced in this chapter.The simulation results of fluid/MC hybrid model which is employed to study the characters of pulse H2 CCP discharge is discussed and analyzed in chapter 3. We mainly analysis the H3+, H2+, H+ densities, electron density and temperature, electron energy probability distribution changing under the influence of different pulse duty cycles, pulse frequencies, voltages and pressures during pulse modulation.