Plasma Diagnostics in Inductively Coupled Plasma Etching Using Cl2/Xe

We investigated the plasma characteristics in an inductively coupled plasma (ICP) etching process using Cl2/Xe by means of a quadrupole mass spectrometer equipped with an ion energy analyzer. It was found that the ion energy of Cl+ increased with decreasing etching pressure, and the quantity of Cl+ increased with decreasing Cl2 flow rate. Ions including etching products such as Si+, Cl+, Xe+ and SiCl x + were observed in the etching plasma. It is suggested from the results of this experiment that the etching profile can be controlled by the in situ monitoring of the quantity of Cl+ ions.