Polymer Cleaning From Porous Low- $k$ Dielectrics in $\hbox {He/H}_{2}$ Plasmas

Porous dielectrics such as SiCOH are used as the insulator in interconnect wiring in microelectronics devices to lower the dielectric constant and therefore decrease the resistive-capacitive delay. After etching a trench in low-k; di electrics in fluorocarbon plasmas, a CF_x polymer remains on the sidewalls, which must be removed in a manner that does not damage the low-k material. This can be accomplished using He/H₂ plasmas, which produce hot H atoms (i.e., energy >; 1 eV). We present images of the distributions of hot H atoms and H⁺ ions from an inductively coupled plasma and their resulting cleaning of a trench etched in SiCOH.