Method of selectively etching titanium-containing materials on a semiconductor wafer using remote plasma generation

A method of selectively etching titanium-containing material on a semiconductor wafer in a fluorine-containing exchange environment comprising:

• providing an energy discharge chamber;
• providing a reaction chamber;
• providing a semiconductor wafer having exposed titanium-containing material to be etched in the reaction chamber;
• providing an energy source;
• providing a flow of gas including a fluorine-containing gas into the energy discharge chamber;
• providing means for applying the energy from the energy source to the gas flowing into the energy discharge chamber;
• applying the energy from the energy source to the gas flowing into the energy discharge chamber to produce a discharge gas including atomic fluorine and ionized species;
• providing a passageway for gas to pass from the energy discharge chamber and the reaction chamber, said passage of gas through the passageway into the reaction chamber requiring a passage time;
• providing a flow of discharge gas from the energy discharge chamber into the passageway;
• said passageway being of sufficient length that the ionized species in the discharge gas will recombine during the passage time therethrough;
• said passageway being sufficiently short that the atomic fluorine will survive longer than the passage time therethrough;
• said passage time of discharge gas through the passageway thereby causing a transformation of the resultant gas into an etching gas containing atomic fluorine, but free of ionized species;
• and
• said flow of discharge gas into the passageway causing a corresponding flow of gas exiting the passageway into the reaction chamber;
• providing a flow of molecular chlorine gas such that it mixes with the intermediate gas, thereby creating an etching gas in the reaction chamber in which a fluorine-chlorine exchange reaction occurs;
• and
• exposing the semiconductor wafer to the etching gas in the reaction chamber, thereby etching the exposed titanium-containing material on the semiconductor wafer.

Method of etching titanium-containing materials on a semiconductor wafer, comprising:

• disposing a semiconductor wafer in a reaction chamber, the semiconductor wafer including titanium-containing materials;
• introducing a fluorine-containing gas to a plasma chamber;
• creating a plasma in the plasma chamber, thereby generating a gas containing atomic fluorine;
• providing the gas containing atomic fluorine to a tube connecting the plasma chamber to the reaction chamber, the tube having a length;
• introducing a gas containing molecular chlorine to the gas containing atomic fluorine at a position along the length of the tube between the plasma chamber and the reaction chamber, thereby creating a gas rich in atomic chlorine;
• introducing the gas rich in atomic chlorine to the reaction chamber to etch the titanium-containing materials on the semiconductor wafer.

Method of etching titanium-containing materials on a semiconductor wafer, comprising:

• disposing a semiconductor wafer in a reaction chamber, the semiconductor wafer including titanium-containing materials;
• generating a chlorine plasma in a plasma chamber remote from the reaction chamber, said chlorine plasma rich in atomic chlorine and having ions;
• and
• communicating the chlorine plasma to the reaction chamber via a tube, said tube having a length sufficient to allow recombination of the ions present in the chlorine plasma so that there is a low concentration of said ions introduced to the reaction chamber, and said tube being limited in length so that there is a high concentration of atomic chlorine introduced to the reaction chamber.