Structure and method for formation of cladded interconnects for MRAMs

A method of forming interconnects, said interconnects comprising four sides, clad, on at least three of the four sides with a self-aligned liner, in a dielectric layer, said dielectric layer comprising a top and a bottom surface and formed over a semiconductor substrate surface, said method comprising:

• etching one or more trenches in the top surface of the dielectric layer, each trench comprising two sides and a bottom;
• coating the one or more trenches and the top surface of the dielectric layer with a first stack, said first stack comprising one of more layers, wherein at least one of the said one or more layers comprises a ferromagnetic material, to form a first liner;
• anisotropically etching the first stack to remove at least the ferromagnetic layer from the horizontal surfaces of the trench bottoms and the top surface of the dielectric layer to form sidewall spacers in the one or more trenches;
• coating at least the top surface of the dielectric layer with a refractory material to form a second liner;
• filling the one or more trenches with a metal conductor and polishing the metal conductor, stopping on the second liner on the top surface of the dielectric;
• recessing the metal conductor of one or more selected metal filled trenches by selectively etching the metal conductor of the one or more selected metal filled trenches, said selective etching being selective to the sidewall spacers;
• forming, over the top surface of the dielectric layer and over the one or more trenches, a second stack, comprising one or more layers, wherein at least one of said one or more layers comprises a second ferromagnetic layer, said second stack forming a third liner;
• and
• polishing with a chemical-mechanical polish removing the second stack from the top surface of the dielectric layer and any non-recessed metal filled trenches while leaving the second stack over the recessed one or more selected metal filled trenches to form a capping layer over the recessed one or more selected metal filled trenches and a planar surface.