The filling seams improvement and properties analyses of tungsten films

Abstract

The preferable conditions for tungsten filling and process parameters on tungsten film properties effect were investigated. The tungsten filling was improved obviously when H2 flow is 1000 sccm, which is ascribed to slower deposition rate. Properly reducing H2 flow could reduce tungsten deposition rate. For every H2 flow reduction of 100 sccm, the film thickness was reduced by 58.5 Å. Decrease nucleation time to 7 s, it was conducive to tungsten filling as well. Researched showed that tungsten filling could be better optimized by reducing H2 flow to 1000 sccm and nucleation time to 7 s simultaneously. The connect through (CT) holes contact resistance (RC) value of new conditions (H2 flow:1000 sccm, nucleation time:7 s) was lower than that of baseline (H2 flow:1600 sccm, nucleation time:10 s) no matter in the N-well or in the P-well, and the drop range was between 9% and 12%. The devices yield of new conditions was 93.7%, slightly higher than that of baseline.