Tadahiro Ishizaka

Cu dry-fill on CVD Ru liner for advanced gap-fill and lower resistance

We describe Cu dry-fill on CVD Ru liner for advanced gap-fill and lower resistance for 22nm-node and beyond. Combination of Ru liner and iPVD Cu filling enables us to fill structures with enlarging Cu grains. Excellent step coverage and Cu wettability on Ru film allow Cu diffusion into trenches. 60% increase of grain size and 10% reduction of wiring resistivity were observed at 50nm-width trenches. We successfully fabricated low resistivity Cu interconnects with additional iPVD Cu planarization followed by CMP.

Low resistance wiring and 2Xnm void free fill with CVD Ruthenium liner and DirectSeed TM copper

Chemical vapor deposited (CVD) Ruthenium liners and DirectSeedTM (DS) copper were used with advanced Electrofill processes to provide lower resistance wiring compared to results using CVD Ru and conventional physical vapor deposited (PVD) Cu seed for back end of line (BEOL) structures. Different annealing temperatures and simulated BEOL thermal stress builds were used to show the difference in resistance. The grain size was also compared to show that the Ru/DS process had larger grains than the Ru/flash-Cu (F-Cu) seed. To further show the advantage of the Ru/DS seed process as a solution for future generations, 2X nm trenches were shown to have complete gap fill and thereby eliminating the need for conventional PVD Cu seed.

Characterization of Advanced Sequential Flow Deposition (ASFD) TiON electrode in MIM structure for leakage current reduction

Advanced Sequential Flow Deposition (ASFD) TiON electrode was developed and mechanism of leakage current reduction with ASFD TiON electrode was studied. ASFD TiON film was fabricated by repeating TiN layer formation and oxidation. Resistivity and crystal structure depended on oxygen concentration in TiON film. Oxygen concentration was controlled precisely by oxidation frequency. Electrical characteristic was evaluated using Metal Insulator Metal (MIM) structure. We observed lower leakage current when oxygen concentration in TiON film was higher. Element analysis of high-k capacitance (Al2O3/ZrO2) indicated that TiON top electrode suppressed leakage current caused by Poole-Frenkel conduction.