MODELING OF CHARGING DAMAGE DURING INTERLEVEL OXIDE DEPOSITION IN HIGH-DENSITY PLASMAS

Monte Carlo simulations of pattern-dependent charging during interleve l dielectric (ILD) deposition in high-density plasmas reveal that the initial conformality of the ILD film plays a crucial role in metal lin e charging up and the subsequent degradation to the buried gate oxide to which the metal line is connected. Line charging occurs when the to p dielectric is thick enough to prevent tunneling currents while the s idewall dielectric thickness still allows tunneling currents to flow t o the metal line; the differential charging of the sidewalls, which in duces the latter currents, is caused by electron shading. The results suggest that charging can be reduced by depositing a more conformal LL D film around the metal Line and/or by increasing the ability of the f ilm surface to dissipate charge. (C) 1998 American Institute of Physic s.