Uniformity consideration in capacitively coupled plasma part 1

In this paper, the plasma uniformity was studied in a capacitively coupled plasma machine using Langmuir probe. The plasma uniformity is affected not only the process parameters, such as input power and pressure, but also the electrode setting. The increase of electrode gap and pairs of electrode significantly improve the plasma uniformity, but decreases the plasma intensity, which are represented by the value of electron temperature Te, electron density Ne, and electron energy density Te*Ne. The perforated electrode helps to improve the plasma uniformity significantly. The result indicates that the edge effect is the main reason caused un-uniform plasma distribution. Furthermore, the spatial plasma distribution along the Z axis is not uniform and plasma intensity in main plasma zone decreases with the distance to the powered electrode. The test result also indicates that the etch rate has the best correlation with electron energy density Te*Ne.