ETCHING FOR 0.15-MU-M-LEVEL PATTERNS WITH LOW MICROLOADING EFFECT USING BEAM PLASMAS GENERATED BY GAS PUFF PLASMA SOURCES

Microloading effects in high-density plasmas, which typically appear a s a difference in the etch rates between the outermost space and the i nner space in a line-and-space (L&S) pattern, were investigated using numerical simulations of ion trajectories and ion fluxes incident on t he patterned surfaces, taking into account the effects of electrical p roperties of the materials, plasmas flowing to a wafer and local charg ing on the patterned surface. The simulation results showed that decre ase of the incident ion flux densities were particularly enhanced in t he area around the outermost space in the L&S pattern. Moreover, the d ifference in the,he incident ion fluxes among the patterns was reduced with increase of the drift velocities of the plasmas. Moreover, exper iments on etching of fine patterns on the scale of around 0. 15 mu m w ere also performed using chlorine beam plasmas with high drift velocit ies generated by gas puff plasma sources. The etch rate of poly-Si sta yed nearly constant with decrease of pattern sizes from 1.0 to 0.15 mu m for time-averaged pressure of [ P-2 ] =0.2 mTorr in the specimen ch amber.