METHOD OF FORMING TRENCH CONTACTS FOR MOS TRANSISTORS

摘要

A method to form transistor contacts begins with providing a transistor that includes a gate stack and first and second diffusion regions formed on a substrate, and a dielectric layer formed atop the gate stack and the diffusion regions. A first photolithography process forms first and second diffusion trench openings for the first and second diffusion regions. A sacrificial layer is then deposited into the first and second diffusion trench openings. Next, a second photolithography process forms a gate stack trench opening for the gate stack and a local interconnect trench opening coupling the gate stack trench opening to the first diffusion trench opening. The second photolithography process is carried out independent of the first photolithography process. The sacrificial layer is then removed and a metallization process is carried out to fill the first and second diffusion trench openings, the gate stack trench opening, and the local interconnect trench opening with a metal layer.