High-density plasma etching of carbon-based low-k materials in a integrated circuit

A method of etching a carbon-based dielectic material, comprising the stps of:

• placing a subtrate containing the carbon-based dielectric material overlaid with a patterned hard mask into a plasma reactor;
• flowing into said reactor a gas mixture comprising an oxygen-containing gas, difluoroethane, and nitrogen;
• and
• exciting said gas mixture into a plasma.

A method of etching a carbon-based dielectric material, comprising the steps of:

• placing a substrate containing the carbon-based dielectric material overlaid with a pattern hard mask into a plasma reactor;
• flowing into said reactor a gas mixture comprising carbon monoxide, a fluorocarbon, and nitrogen;
• and
• exciting said as mixture into a plasma.

A method of etching a carbon-based dielectric material, comprising the steps of:

• placing a substrate containing the carbon-based dielectric material overlaid with a patterned hard mask into a plasma reactor;
• flowing into said reactor a gas mixture comprising an oxygen-containing gas, a fluorocarbon, and nitrogen, wherein said flowing step includes a first substep of flowing a first amount of said oxygen-containing gas followed by a second substep of flowing a second amount of said oxygen-containing gas less than said first amount;
• and
• exciting said gas mixture into a plasma.

A method of etching a hole in a carbon-based dielectric material, comprising the steps of:

• disposing in a plasma reactor a substrate containing the carbon-based dielectric material overlaid with a patterned hard mask surrounding an area in which said hole is to be etched;
• flowing into said reactor a gas mixture comprising a first amount of an oxygen-containing gas and a second amount of nitrogen at least equal to said first amount;
• maintaining a pressure in said reactor of less than 5 milliTorr;
• and exciting said gas mixture into a plasma to thereby etch said hole.

A process for etching a substrate including a substantially silicon-free carbon-based dielectric overlaid with a silicon oxide hard mask and underlaid by a silicon nitride stop layer, comprising:

• flowing into a plasma reaction chamber a etching gas mixture comprising a first amount of oxygen and a second amount of nitrogen and containing substantially no fluorine-containing gas, said first and second amounts differing by no more than a factor of four;
• applying RF bias power to a pedestal electrode supporting said substrate;
• and
• exciting said etching gas mixture into a plasma.

A process for etching a substrate including a substantially silicon-free carbon-based dielectric overlaid with a silicon oxide hard mask and underlaid by a silicon nitride stop layer, comprising:

• flowing into a plasma reaction chamber a etching gas mixture consisting essentially of a first amount of oxygen and a second amount of nitrogen and containing substantially no fluorine-containing gas, said first and second amounts differing by no more than a factor of four;
• applying RF bias power to a pedestal electrode supporting said substrate;
• and
• exciting said etching gas mixture into a plasma.

A method of etching a carbon-based dielectric material, comprising the steps of:

• placing a substrate containing the carbon-based dielectric material overlaid with a patterned hard mask into a plasma reactor;
• flowing into said reactor a gas mixture comprising an oxygen-containing gas, a hydrofluoromethane, and nitrogen and including substantially no argon;
• and
• exciting said gas mixture into a plasma.

A method of etching a hole in a carbon-based dielectric material, comprising the steps of:

• disposing in a plasma reactor a substrate containing the carbon-based dielectric material overlaid with a patterned hard mask surrounding an area in which said hole is to be etched;
• flowing into said reactor a gas mixture comprising a first amount of an oxygen-containing gas and a second amount of nitrogen at least equal to said first amount and including substantially no argon and substantially no fluorine-containing gas;
• and
• exciting said gas mixture into a plasma to thereby etch said hole.