Plasma properties of a negative ion plasma reactive ion etching system

In high density reactive ion etching (RIE) systems it has been found that t here is an aspect ratio charging effect which causes damage, RIE lag and lo ss of ion current to the bottom of high aspect structures. It has been show n by a number of authors, that one way of reducing these effects is to redu ce the electron temperature of the plasma which is above the wafer. We have characterized the plasma properties of a medium to high density plasma sys tem which uses a magnetic filter in an inductively coupled plasma (ICP) to produce a low temperature negative ion plasma above the wafer. At 4 mTorr, the electron temperature of this negative ion plasma is 1/3 of that for the same system without the filter. We present uniformity data and electron te mperature data versus pressure and magnetic potential.