Vacuum Environment Of Sputter Coating

- Jun 26, 2018-

1. Vacuum Chamber Base Pressure


(1) A variety of magnetron sputtering coating processes must be performed in a vacuum chamber; the vacuum degree of the closed metal cavity is generally required to reach 10-3Pa~10-5Pa; some coating processes may even have higher vacuum requirement.


(2) Due to the deflation of the adsorbed gas on the inner wall of the vacuum metal cavity and the magnetron target surface, it takes a long time to reach the required vacuum level of the coating at first time of pre-pumping vacuum. After reaching the required vacuum degree, because the deflation is basically completed, the vacuum time will be greatly reduced at the second time re-evacuation vacuum.


2. Working gas


According to different film layers and process requirements, partial pressure inert gas are discharge the in the vacuum chamber at a pressure of 0.1 to 1 Pa (RF magnetron sputtering: 0.1 Pa to 0.05 Pa) in magnetron sputtering process. The inert gas are commonly used gases, such as argon Ar, Helium Kr, Helium Xe, Helium Ne and Nitrogen N2. Argon is usually used as working gas for magnetron sputtering because of its low price and easy availability.


3. Working Gas Pressure


(1) The working gas pressure of DC and IF pulsed magnetron sputtering is generally between 0.3~0.8Pa (typical value is 5*10-1 Pa).


(2) RF magnetron sputtering can be performed normally under the working pressure of 10-1~10-2 Pa.


(3) The magnetron sputtering process of some cathode targets (such as low requirements on the purity and surface roughness of the film layer) can also be efficiently deposited under a working pressure of 1 Pa ~ 10 Pa or even higher.


(4) Various factors such as the size of the vacuum chamber, the gas flow rate, the vacuum pumping speed, and the opening and closing angle of the gate valve may affect the working gas pressure. The final detection value of the working gas pressure should actually be regarded as the result of the dynamic balance of the gas flow-vacuum pumping speed and the opening and closing angle of the gate valve.