Effects of collimator aspects ratio and deposition temperature on copper sputtered seedlayers

We have investigated the effects of collimator aspect;ratio and deposition temperature of copper seedlayers to improve conformality in aggressive single and dual damascene structures. Collimation filters of various aspect ratios were used to deposit copper seedlayers which were then filled using electro deposition. It was found that collimators of 1.0 aspect ratio resulted in the best seedlayer conformality, as evidenced by film structure coverage and quality of plating fill. Further, electrical testing using 68000 via chains also showed the average via resistance to be lowest and the chain opens yield: to be highest with the 1.0 aspect ratio condition. Finally, thermal effects on seedlayer conformality were examined by varying the wafer temperature during deposition. It was observed that,deposition temperatures of 100 degrees C and lower resulted in smoother films as compared to seedlayers deposited at 200, 300, or even 400 degrees C. (C) 1999 American Vacuum Society. [S0734-2101(99)08604-2].