Suraj Rengarajan

Room Temperature Self-Annealing of Electroplated and Sputtered Copper Films

Self-annealing properties of electroplated and sputtered copper films at room temperature were investigated in this study, in particular, the effect of copper film thickness, electrolyte systems used, as well as their level of organic additives for electroplating. Real-time grain growth was observed by transmission electron microscopy. Sheet resistance and X-ray diffraction measurements further confirmed the recrystallization of the electroplated copper film with time. The recrystallization of electroplated films was then compared with that of sputtered copper films.

Barrier crystallographic texture control and its impact on copper interconnect reliability

The impacts of barrier micro-structure on Cu seed and electro copper plating (ECP) film have been investigated in terms of seed sheet resistance (R/sub s/) stability, crystal orientation, and wetting properties; ECP film surface morphology and CMP defects. We have studied the effect of these parameters using 4-point probe, X-ray diffraction (XRD), scanning electron microscopy (SEM), and SEM vision. We also studied barrier impact on via resistance and interconnect reliability using E-test measurement and stress migration test. It was found that barrier layer micro-structure can manipulate seed layer and ECP film properties, which affect E-test performance. The seed layer deposited on highly <110>-oriented /spl alpha/-Ta underlayer shows better Cu <111> orientation, resulting in a seed with stable R/sub s/, better wetting properties, smoother ECP film, and lower defects. In addition, it shows lower via resistance and better interconnection reliability.

A new PVD sputtering source for metal gate application

A new PVD source for metal gate applications has been systematically characterized. Results from the study indicate that the new source provides very low trap density (<1 times 1011/cm2 eV), excellent film thickness (and sheet resistance) non-uniformity (<1% 1sigma) and a wide range in deposition rates (from 0.4 Aring/s to 6 Aring/s), making it suitable for depositing metal films directly on gate oxides in 45nm and 32nm technology nodes