Low resistance small metal contact for high temperature application

A reliable small metal contact (similar to 0.18 mu m) withstanding high tem perature post-thermal budget (similar to 800 degrees C for 30 min) is devel oped for a bit-line (BL) contact of gigabit scaled dynamic random access me mories with capacitor-over BL structure. Cobalt (Co) salicidation on the so urce/drain regions is indispensable to have low BL contact resistance (R-c) . The CoSix layer under the contact hole prevents the contact liner (Ti) fr om reacting with the sub-silicon. Thus, TiSix agglomeration as well as dopa nt-TiSix interaction is suppressed even with relatively high postannealing temperature. Thin SiN layer on the CoSix is an effective etch stopper durin g contact etch and protects the thin CoSix layer from the etch damage. Use of an Ar+ soft inductively coupled plasma cleaning instead of the wet chemi cal cleaning after contact etch is another key factor to attain a reliable BL contact process. The low R-c and contact leakage are ensured when ion-me tal-plasma Ti/TiN liner is utilized. (C) 1999 American Vacuum Society. [S07 34-11X(99)15406-4].