What Is The Effect Of Chamber Pressure On Etching?

What is the Effect of Chamber Pressure on Etching?

How is the chamber pressure regulated? What is the effect on the results of etching?

What is Chamber Pressure? Chamber pressure refers to the pressure of the gas in the process chamber of the etching equipment, usually measured in Torr or Pascal.

o What determines the chamber pressure?
1.The higher the gas flow, the greater the pressure.
2.The vacuum pump is vented, and the higher the pump speed, the lower the chamber pressure.

o Effect of chamber pressure on etching
1.Ion bombardment energy. Low pressure, large mean free path of molecules, small collision probability of ions, less energy dissipation, so high energy.
2.Ratio of ions to free radicals. At low pressure, the proportion of ions is high, which is conducive to physical etching. At high pressure, the high proportion of free radicals favors chemical etching.

Etching uniformity. At high pressure, high-frequency collisions will reduce the gas flow rate, and free radicals will more easily diffuse to all parts of the wafer surface, including the edge area, and the concentration of reactants exposed to the entire wafer surface will be uniform, and the etching rate will tend to be the same.

Summary
0020-24896 COVER RING 6" SST 101 AL

0020-28205 6" TI COVER RING
With the increase of chamber pressure, the etching reaction gradually transforms from physical etching to physical + chemical etching to chemical etching.