Magnetic tunnel junction device and fabrication

A method comprising:

• forming magnetic tunnel junction layers above a bottom electrode;
• patterning a magnetic tunnel junction structure using an etching process stopping at the bottom electrode;
• performing an in-situ sputter clean to remove a sidewall oxidation layer from a sidewall of the magnetic tunnel junction structure;
• forming a diffusion barrier layer above and adjacent to the magnetic tunnel junction structure, wherein the diffusion barrier layer is formed of a first material;
• etching back the diffusion barrier layer, wherein etching back the diffusion barrier layer includes:
• removing a a first portion of the diffusion barrier layer from a top of the magnetic tunnel junction structure;
• and
• leaving a second portion of the diffusion barrier layer adjacent to the magnetic tunnel junction structure;
• forming a cap layer above and adjacent to the second portion, wherein the cap layer is above the bottom electrode, and wherein the cap layer is formed of a first material;
• forming an insulating layer above the cap layer;
• planarizing the insulating layer and the top of the magnetic tunnel junction structure;
• and
• connecting the top of the magnetic tunnel junction structure to a conductive layer.

A method comprising:

• forming a bottom cap layer above a first insulating layer;
• performing a first copper damascene process to open a bottom metal trench and a bottom via in the first insulating layer, to plate copper, and to perform a copper chemical mechanical planarization;
• forming a bottom electrode above the bottom cap layer and above the copper in the bottom metal trench;
• forming magnetic tunnel junction layers above the bottom electrode;
• forming a hardmask above the magnetic tunnel junction layers;
• patterning magnetic tunnel junction structures;
• forming a diffusion barrier layer above and adjacent to the magnetic tunnel junction structures and above the bottom electrode;
• etching back the diffusion barrier layer, leaving a portion of the diffusion harrier layer adjacent to the magnetic tunnel junction structures;
• forming a cap layer above and adjacent to the portion of the diffusion barrier layer adjacent to the magnetic tunnel junction structures and above the bottom electrode;
• forming a second insulating layer above the cap layer;
• planarizing the second insulating layer and opening tops of the magnetic tunnel junction structures;
• forming a top electrode above the planarized second insulating layer and above the tops of the magnetic tunnel junction structures;
• patterning the top electrode and the bottom electrode;
• forming and planarizing a third insulating layer above the patterned top electrode and above the bottom cap layer;
• and
• performing a second copper damascene process to open a top metal trench in the third insulating layer to the patterned top electrode, to plate second copper, and to perform a second copper chemical mechanical planarization.

A method comprising:

• a first step for forming a magnetic tunnel junction structure above a bottom electrode;
• a second step for forming a diffusion barrier layer above and adjacent to the magnetic tunnel junction structure, wherein the diffusion barrier layer is formed of a first material;
• a third step for etching back the diffusion barrier layer, wherein etching back the diffusion barrier layer includes removing the diffusion barrier layer above the magnetic tunnel junction structure;
• a fourth step for forming a cap layer above and adjacent to a portion of the diffusion barrier layer that is adjacent to the magnetic tunnel junction structure, wherein the cap layer is above the bottom electrode, and wherein the cap layer is formed of the first material;
• a fifth step for forming an insulating layer above the cap layer;
• and
• a sixth step for connecting a top of the magnetic tunnel junction structure to a conductive layer.