Title :
Titanium corrosion in 0.25 μm metal interconnects
Author :
Koh, Leong-Tee ; Chok, Kho-Liep ; Li, He Ming ; Chooi, Simon Y.M.
Author_Institution :
Dept. of Deep Submicron Integrated Circuit, Inst. of Microelectron., Singapore
Abstract :
This paper studies the effect of post-metal etch wet polymer cleaning on the via resistance of design structures with various enclosures of overlying metal film stacks in prevailing tungsten (W) plugged vias. We observed a new via failure mechanism of enhanced galvanic corrosion of the Ti adhesion layer (anode) immediately overlying the exposed W via (cathode) during the strip process. We solved the high via resistance issue by using an alternative strip chemical which is considered to be an inactive electrolyte for the galvanic reaction between the Ti glue layer sidewall edge and exposed W via
Keywords :
corrosion; etching; integrated circuit interconnections; integrated circuit metallisation; integrated circuit reliability; integrated circuit testing; surface chemistry; surface cleaning; titanium; 0.25 micron; Ti adhesion layer; Ti glue layer sidewall edge; W plugged vias; W-Ti; design structures; enhanced galvanic corrosion; exposed W via; galvanic reaction; inactive electrolyte; metal interconnects; overlying metal film stacks; post-metal etch wet polymer cleaning; strip chemical; strip process; titanium corrosion; tungsten plugged vias; via failure mechanism; via resistance; Adhesives; Cleaning; Corrosion; Failure analysis; Galvanizing; Polymer films; Strips; Titanium; Tungsten; Wet etching;
Conference_Titel :
Interconnect Technology, 1999. IEEE International Conference
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-5174-6
DOI :
10.1109/IITC.1999.787074
