Reliability improvement in high aspect ratio contacts and vias filled with blanket tungsten CVD film

This paper reports a new open failure observed in high aspect ratio contacts and vias filled with blanket tungsten CVD film. This failure mode has been proved to be induced by the poor film quality of the sputtered glue layer at the bottom of a hole. Open failure in contacts has been suppressed by lowering the deposition temperature of the sputtered glue layer together with the optimization of CVD process conditions. Open failure in vias has been suppressed by collimation sputtering of the glue layer at low temperature.