The distribution of gas is extremely important for the plate substrate coating. 

Through mechanical structure design, the change rate of gas density is as small as possible 

in the sputtering deposition area. 

While outside the region, the flow conduction of the system is as large as possible in order to improve 

the gas utilization rate and the efficiency of the pumping system. 

The mechanical component or structure of which control the gas distribution includes three parts as: 

the gas distribution system,the structure of the vacuum chamber and the pumping system.