CHEMICAL VAPOR DEPOSITED TUNGSTEN INTERCONNECT TECHNOLOGY

摘要

A 'composite' chemical vapor deposited tungsten process was developed for interconnect application. This film demonstrated stress levels < 550 MPa tensile, whilst maintaining acceptable fill properties. It was found that the SiH_4 initiation step (no WF_6 flowing) was critical for the control of Si consumption and junction leakage, and that a higher (40 Torr) process pressure provided substantial benefits as compared to initiation steps performed at lower pressures (4 Torr). The addition of relatively low N_2 partial pressures to the process gas mixture greatly reduced the surface roughness of the CVD-W film, with no detrimental effect to other film proprieties.