EFFECT OF THE TI TIN BILAYER BARRIER AND ITS SURFACE-TREATMENT ON THERELIABILITY OF A TI/TIN/ALSICU/TIN CONTACT METALLIZATION/

The use of an AlSiCu/TiN bilayer for the metallization of 1.0-mu m-dia m and 1.4-mu m-deep straight wall contacts to 0.2-mu m-deep n(+) and p (+) diffusions, results in a n(+)/p(-) and a p(+)/n(.)(-) junction lea kage lower than 10 pA even after nine heat treatments (60 min each) at 450 degrees C. However, there is a very important degradation of the contact chain resistance statistics at small contact size. On the othe r hand, the use of a Ti/TiN bilayer barrier under the AlSiCu/TiN inter connect maintains a n(+)/p(-) and a p(+)/n(-) junction leakage lower t han 20 pA and prevents the degradation of the contact chain resistance statistics after the nine heat treatments. It is finally demonstrated that a vent in nitrogen followed by a momentary air exposure of the T i/TiN bilayer barrier results in larger contact resistance than a vent in nitrogen followed by a one hour long air exposure of the Ti/TiN bi layer barrier before the deposition of the AlSiCu/TiN interconnect. (C ) 1996 American Vacuum Society.