Corrosion-free dry etch patterning of magnetic random access memory stacks: Effects of ultraviolet illumination.

Individual layers of Ni[sub 0.8]Fe[sub 0.2], Ni[sub 0.8]Fe[sub 0.13]Co[sub 0.07], TaN, and CrSi, and a full magnetic random access memory stack consisting of NiFeCo/CoFe/Cu/CoFe/NiFeCo/TaN/CrSi multilayers, were etched in high density Cl[sub 2]/Ar plasmas either with or without concurrent ultraviolet (UV) illumination. Under optimized conditions, etch rate enhancement up to a factor of 5 was obtained for NiFeCo, TaN, and CrSi with UV illumination; whereas the etch rate of NiFe was retarded. Post-etch cleaning with H[sub 2] or SF[sub 6] plasmas or H[sub 2]O rinsing was necessary in all cases in order to prevent corrosion of the metal layers from chlorinated etch residues. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]