A fast dry etching of magnetic tunnel junction using a new plasma source

Abstract

We have developed a new plasma reactor which can generate high density plasma at low neutral gas pressure. The ion current density in the new plasma reactor is more than ten times higher than that in the conventional inductively coupled plasma (ICP) reactor at neutral gas pressure lower than 1mTorr. It is remarkable that 25nm-thick magnetic tunnel junction (MTJ) stack can be etched and a 26nm-depth oxide recess can be formed within 40 seconds with the newly designed plasma reactor.