Optimized tungsten contact plug process via use of furnace annealed barrier layers

A method for fabricating a MOSFET device, on a semiconductor substrate, using a contact hole lined with titanium for adhesive purposes, lined with titanium nitride for barrier purposes, and filled with tungsten, to provide electrical contact between an active device region and an overlying interconnect metallization, comprising the steps of:

• providing device elements on said semiconductor substrate;
• deposition of a dielectric layer on said semiconductor substrate, including deposition on said device elements;
• photolithographic processing to open a region in photoresist, exposing said dielectric layer, directly over a specific region of said device element;
• anisotropic etching of said dielectric layer, in opened region of said photoresist, to create a contact hole to said specific region in said device element;
• ion implanting a first conductivity imparting dopant into said specific region of said device element to create a heavily doped N type region;
• surface cleaning of said heavily doped N type region;
• deposition of a titanium layer on said dielectric layer, on sides of said contact hole, and on said heavily doped N type region;
• deposition of a titanium nitride barrier layer on said titanium layer;
• annealing in an nitrogen ambient, at a temperature between about 550.degree. to 650.degree. C., for a time between about 45 to 75 min;
• deposition of a tungsten on said titanium nitride barrier layer, completely filling said contact hole;
• etch back of said tungsten to form a tungsten plug in said contact hole;
• deposition of an interconnect metallization layer;
• and
• patterning of said interconnect metallization layer to form metal interconnect structure.