Contact via

A method of fabricating a back end of line (BEOL) metallization structure, the method comprising:

• forming a first interconnect structure by patterning a first dielectric layer to form a trench therein and depositing a metal conductor in the trench;
• forming a recess in the metal conductor;
• forming a second dielectric layer onto the first interconnect structure, wherein the second dielectric layer fills the recess in the metal conductor;
• planarizing the second dielectric layer to the first dielectric layer;
• patterning the second dielectric layer to form a via contact opening to expose a surface of the metal conductor in the first interconnect structure;
• filling the via opening with a metal to form a metal filled via;
• depositing layers of a metal and at least one insulating layer to form a multilayer stack;
• depositing a metal hardmask and a dielectric hardmask onto the multilayer stack;
• patterning the dielectric hardmask and the metal hardmask to provide a patterned dielectric hardmask and metal hardmask, wherein the patterned dielectric hardmask and metal hardmask overlies the metal filled via;
• and
• etching the multilayer stack using an ion beam etch process to form a pillar device, wherein a width dimension of the pillar device is greater than a width dimension of the metal filled via.

A method of fabricating a back end of line (BEOL) metallization structure, the method comprising:

• forming a first interconnect structure by patterning a first dielectric layer to form a trench therein and depositing a metal conductor in the trench, wherein the metal conductor has a top surface coplanar to a top surface of the first dielectric layer;
• forming a recess in the metal conductor;
• forming a second dielectric layer on the first interconnect structure, wherein the second dielectric layer fills the recess and overlies the first dielectric layer;
• reactive ion etching the second dielectric layer to form a via opening and expose a surface of the metal conductor in the first interconnect structure;
• filling the via opening with a metal to form a metal filled via;
• depositing layers of metals and at least one insulator material to form a multilayer stack;
• depositing a metal hardmask layer onto the multilayer stack;
• depositing a dielectric hardmask layer onto the metal hardmask;
• patterning the dielectric hardmask and the metal hardmask layers to provide a patterned dielectric hardmask and metal hardmask, wherein the patterned dielectric hardmask and metal hardmask overlie and have a width dimension greater than a width dimension of the metal filled via;
• and
• etching the multilayer stack using an ion beam etch process, wherein the multilayer stack completely covers the metal filled via.