Self-aligned damascene gate with contact formation

Abstract

In order to form a self-aligned damascene gate with an attendant contact or contacts, a thick layer of dielectric material is formed over a semiconductor substrate in which drain and source regions have previously been implanted and annealed. This dielectric layer is polished for planarity, a combined gate and contact mask is used to pattern the dielectric, and the interlayer dielectric is etched and the resist is stripped. The gate dielectric is deposited and polysilicon is then deposited over the dielectric and doped by implantation and then annealed. This polysilicon layer is polished to the dielectric level. The wafer is then masked to cover the gate and the polysilicon is anisotropically etched off in the contact areas. The exposed polysilicon at the gate site and the silicon exposed at the contact site are then salicided.