A method of high aspect ratio contact etching a substantially vertical
contact hole in an oxide layer using a hard photoresist mask is
described. The oxide layer is deposited on an underlying substrate. A
plasma etching gas is formed from a carbon source gas. Dopants are mixed
into the gas. The doped plasma etching gas etches a substantially
vertical contact hole through the oxide layer by doping carbon chain
polymers formed along the sidewalls of the contact holes during the
etching process into a conductive state. The conductive state of the
carbon chain polymers reduces the charge buildup along sidewalls to
prevent twisting of the contact holes by bleeding off the charge and
ensuring proper alignment with active area landing regions. The etching
stops at the underlying substrate.