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

Chemical vapor deposited (CVD) Ruthenium liners and DirectSeed^TM (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.