High density hexagonal MTJ array with 72 nm pitch and 30 nm CD by using advanced DRAM patterning solution and ion beam etch

A hexagonal honeycomb magnetic tunneling junction array with 72 nm pitch and 30 MgO critical dimension was successfully fabricated on a 1× dynamic random access memory platform by using mature patterning solution ion beam etch. To our knowledge, both size are the world’s smallest ones for industrial arrays. obtain such high density small sized array, cross self-aligned double technique, triple layer hard mask scheme, an optimized etch condition were adopted. During optimization of process, dependence pillar profile parameters has also been systematically studied. The depth oxide recess sidewall angle increased amount, while remainder thickness decreased increasing amount.