Novel method to etch copper barrier film

A method of opening a barrier film comprising at least one of Co, Ru, or Ta, Ti. TaN, or TiN below copper structures in a stack, comprising:

• placing the stack in a dry plasma processing chamber;
• providing a constant flow of an inert carrier gas;
• providing a pulsed gas into the plasma processing chamber, wherein the providing the pulsed gas comprises:
• providing a pulsed H2 containing gas;
• and
• providing a pulsed halogen containing gas, comprising at least one of HBr, BCl3, Cl2, CF4, or NF3, wherein the pulsed H2 containing gas and the pulsed halogen containing gas are pulsed out of phase, and wherein the pulsed H2 containing gas has an H2 high flow period and the pulsed halogen containing gas has a halogen containing gas high flow period, wherein a ratio of the H2 high flow period to the halogen containing gas high flow period is between 2:1 to 20:1 inclusive;
• forming the constant flow and gas pulsed gas into a plasma, comprising:
• providing an RF power signal between 200 and 1000 Watts during the providing the constant flow gas and pulsed gas into the plasma processing chamber;
• and
• providing a bias power between 50 and 500 volts during the providing the constant flow gas and pulsed gas into the plasma processing chamber;
• exposing the copper structures and the barrier film to the plasma, which etches the barrier film.

A method of opening a barrier film comprising at least one of Co, Ru, or Ta, Ti. TaN, or TiN below copper structures, comprising:

• providing a wet and dry treatment comprising at least three cycles, wherein each cycle comprises sequential steps of:
• providing a wet treatment of the barrier film below the copper structures, by providing an acidic, buffer, or chelator bath or a bath comprising at least one of acetyl acetone, hexafluoroacetylacetone or hydrogen peroxide;
• and
• providing a dry plasma sputtering of the barrier film below the copper structures;
• providing a carbon deposition on the copper structures after the providing the wet and dry treatment;
• and
• providing a dry halogen containing etch after providing the carbon deposition.