Enhanced high performance reliable AlSi/TiW metallization for 1.0 μm CMOS process

Summary form only given. A reported AlSi/TiW metal system is developed with enhanced performance which is anticipated to upgrade the AlSi/TiW metallization. Standard VLSI process is followed for the contact formation process. Before the AlSi deposition, TiW is deposited and annealed using RTA, at a temperature ranging from 625°C to 700°C. AlSi is deposited over TiW followed by the conventional patterning steps. Relatively low temperature alloy is then adapted either by furnace or RTA. The average P+ contact resistance for a 1.2×1.2 μm² contact is about 25 ohms as compared to 80 ohms for the conventional process. No junction degradation is observed at all for this higher temperature anneal process. A bonus is that the hillocks can be largely eliminated. The sheet resistivity for AlSi/TiW alloyed at 450°C, 30 min. is twice as large as that for samples alloyed at 410°C, 30 min. or 425°C, 40 sec with RTA. This difference might signal the interaction between AlSi and TiW at 450°C. It is also found that the metal shortening rate bears a relationship to the thickness of TiW