Measurement of ion current distribution on a three-dimensional workpiece in the positive pulse bias PBII

Abstract

The feasibility of a metal liner for controlling the wall current has been studied for the positive pulse bias (PPB) method, a new proposing method of the PBII process. In the PPB method, the plasma is positively biased with respect to the grounded workpiece. While it has merits over a negative pulse bias (NPB) method, it requires an enclosure or a liner to suppress the electrical current to the chamber wall. We have tested a floating stainless steel liner in place of the Kapton liner previously used to avoid plasma contamination; the plasma floating potential, the ion energy spectrum on a disc target and the ion current distribution on a trench target have been investigated in an argon plasma of 1015m−3 supplied into the liner from the ICP source. The results have proved that the metal liner is quite suitable for the PPB method.