Title :
A double metal process: using a TiW/Mo sandwich as the first layer metal
Author :
Hawley, Frank ; Levi, Amitay ; Vasche, Greg ; Caywood, J.M. ; Houck, Bill ; Boyce, John ; Tso, Lin
Author_Institution :
Xicor. Inc., Milpitas, CA, USA
Abstract :
A dual-layer metallization process is studied using a tungsten 10% titanium/molybdenum sandwich (TiW/Mo) first metal with Al/0.5% Cu for the second metal. This metallization process have very reliable shallow-junction contacts without junction spiking, with very high electromigration resistance, and with a very smooth defect-free surface throughout the process. Contact resistance of 50 and 30 Omega - mu m/sup 2/ for P and N type silicon, respectively, is achieved. The TiW/Mo film stress is studied and on optimum condition for low compressive stress is defined. Electromigration data is presented showing TiW/Mo to be at least an order of magnitude better than Al/Si. The intermetal oxide layer is a planarized sandwich of LTO/SOG/LTO providing a smooth positive slope surface for the metal 2. Metal 1/metal 2 via resistances are studied with 1.25 Omega - mu m/sup 2/ values obtained.<>
Keywords :
aluminium alloys; contact resistance; copper alloys; electromigration; integrated circuit technology; metallisation; molybdenum; titanium alloys; tungsten alloys; AlCu; LTO/SOG/LTO; Si; TiW-Mo sandwich; contact resistance; defect-free surface; dual-layer metallization process; electromigration resistance; intermetal oxide layer; planarized sandwich; positive slope surface; reliable shallow-junction contacts; via resistances; Contact resistance; Electromigration; Etching; Implants; Integrated circuit interconnections; Metallization; Plugs; Temperature; Titanium; Tungsten;
Conference_Titel :
VLSI Multilevel Interconnection Conference, 1988. Proceedings., Fifth International IEEE
Conference_Location :
Santa Clara, CA, USA
DOI :
10.1109/VMIC.1988.14186
