Directional Plasma CVD Technology for Sub-quarter-micron Feature Size Multilevel Interconnections

A new plasma chemical vaper deposition (CVD) technology, which provides outstanding film step coverage for sub-quarter-micron, high-aspect-ratio steps on ultralarge semiconductor integrated (ULSI) device surfaces, has been developed. The technology employs a bias plasma CVD deposition system with wide-gap electrodes and reaction gases of triethoxysilane (TRIES) and oxygen. This technology improves the step coverage of SiO2 films by reducing the lateral ledge to less than 60% of that associated with conventional plasma CVD. It also improves the film quality of the SiO2 deposited on the step sidewalls in reducing the sidewall etching rate to less than 50% of that of conventional films. This technology has been applied to an interlevel dielectric (ILD) process in conjunction with organic spin-on-glass (SOG), and the ILD parasitic capacitance was reduced to about 70% of that in conventional plasma CVD. This technology is very promising for application to 0.2 µm feature size ULSI interconnections.