Patent ID: 8722543
Filing Date: 2014-05-13
Classification: H01L,Y10T

Abstract:
1. A composite hard mask used for the fabrication of a MTJ element in a MRAM device, comprising: (a) a lower non-magnetic spacer made of a metal or metal alloy that is one of MnPt, Ru, Cu, Zr, Mg, or NiFeHf with a lower surface that contacts a free layer in a MTJ stack of layers, said non-magnetic spacer has an etch rate substantially higher than an overlying conductive layer and the MTJ stack of layers including a pinned layer and a tunnel barrier layer in a single step to define a MTJ element; (b) a middle conductive layer that is one of Ta, TaN, TiN, and W and contacts an upper surface of said non-magnetic spacer and has an etch rate substantially higher than the non-magnetic spacer; and (c) an upper dielectric layer that is comprised of silicon oxide, silicon nitride, silicon carbide, or silicon oxynitride and contacts an upper surface of the middle conductive layer and wherein all layers including upper dielectric layer and middle conductive layer and the lower non-magnetic spacer have a common sidewall.