Chengfeng Zhizhi plasma etching machine introduces the characteristics of dielectric barrier gas discharg

• Categories:Company Dynamics
• Author:Plasma cleaning machine-CRF plasma plasma equipment-plasma surface treatment machine manufacturer-chengfeng intelligent manufacturing
• Origin:
• Time of issue:2021-10-13
• Views:

(Summary description)Chengfeng Zhizhi plasma etching machine introduces the characteristics of dielectric barrier gas discharge: For the various working gases of the plasma etching machine, the inert gas is uniformly distributed in the discharge dielectric barrier at atmospheric pressure, and the metal circular electrode with the parallel plate structure can be used to study the discharge characteristics and properties of the inert gas in the dielectric barrier. The diameter of the electrode used in this study is 50mm, and the two electrodes are respectively coated with a layer of 1mm thick quartz glass, with a relative permittivity of 3.9 and an air gap interval of 5mm. The electrode and the barrier medium are placed in the discharge chamber, and the discharge chamber is first evacuated to below 5 Pa, and then filled with high-purity helium, argon and other gases. Use the ICCD high-speed camera to capture the side image of the DBD discharge, use the ITO transparent electrode as the bottom electrode and the 45° plane lens to assist, you can shoot to the bottom of the discharge area. The measured applied voltage Va, the total discharge current Vi and the calculated air gap voltage Vg waveform, wherein the measured quasi-sinusoidal dashed line is the applied voltage waveform, and the thin solid line is the current waveform. There is a current pulse on the applied voltage in every half cycle, which is a typical feature of uniform dielectric barrier discharge under the atmospheric pressure of a plasma etching machine. When studying the discharge mechanism, people are more concerned about the Vg value of the air gap voltage, but due to the existence of the barrier medium, the air gap voltage cannot be measured directly. Using the measured voltage Va and discharge current i, combined with the equivalent circuit of the plasma etching machine DBD, the voltage g can be calculated. Based on the measured voltage Va and the total discharge current i, the real voltage Vg on the air gap and the current id flowing in the flowing air gap are calculated. In this process, Vm(to) characterizes the cumulative effect of the discharge on the surface of the dielectric before to. When using the Vm(to) method to calculate, make the average value of Vm(t) 0 within an applied voltage cycle, that is, there is no self-polarization in the medium. The displacement current in helium discharge is much smaller than the transport current, so the transport current is basically the same as the actual measured total current, and it is no longer calculated separately. In the air gap, the voltage Vg increases with the increase of the applied voltage Va, and then decreases rapidly with the air gap discharge. This inflection point corresponds to the breakdown voltage of the air gap. When confirming the spatial uniformity of the discharge of the plasma etching machine, a 10ns discharge image can be taken near the peak of the discharge current, and it is found that the discharge has no light and dark discharge filaments, indicating that the discharge is uniform in space, so this is The discharge that is relatively easy to obtain in atmospheric pressure helium gas is uniform discharge; at the same time, it can be seen that there is a high-brightness light-emitting layer near the instantaneous cathode, which is a typical feature of glow discharge. Therefore, it can be concluded that the atmospheric pressure helium discharge belongs to the glow discharge. Light discharge. It can be seen from the voltage, current waveform and side light emission of the plasma etching machine that the power frequency is about 33kHz, the air gap thickness is about 6mm, the positive electrode is on the top, and the negative electrode is on the bottom. In addition, comparing the voltage and current waveform diagrams and the side emission diagrams, it can be seen that helium and helium DBD are very similar. The difference between the two is that their positive column area is not obvious, while the Faraday dark area is almost non-existent. The breakdown strength of the gas gap voltage waveform can be calculated. The breakdown strength of 6mm gas is 1kV/cm, which is much lower than that of atmospheric pressure gas of 30kV/cm. This low breakdown field strength is the guarantee for achieving uniform discharge of helium and gas at atmospheric pressure of the plasma etching machine. Chengfeng Zhizao has focused on plasma etching machine technology for 20 years. If you have any questions, please click on the Chengfeng Zhizao online customer service for consultation. Chengfeng Zhizao is waiting for your call!