Methods and apparatus for etching semiconductor wafers and layers thereof

In a plasma processing chamber, a method for etching through an aluminum-containing layer and TiN layer, said TiN layer being disposed above said aluminum-containing layer, comprising:

• a first etching step, said first etching step etches at least partially through said TiN layer using a first source gas composition, said first source gas composition comprising a Cl.sub.2 etchant and a first mixture, said first mixture comprising HCl and CHF.sub.3, said first source gas composition having a first flow ratio of said Cl.sub.2 etchant to said first mixture.

In a plasma processing chamber, a method for etching through a selected portion of an aluminum-containing layer and a titanium-containing layer, said titanium-containing layer being disposed above said aluminum-containing layer, said aluminum-containing layer being disposed on a wafer, comprising:

• a first etching step, said first etching step etches at least partially through said titanium-containing layer using a first source gas composition, said first source gas composition consisting essentially of said Cl.sub.2 etchant and a first mixture, said first mixture consisting essentially of HCl and CHF.sub.3, said first source gas composition having a first flow ratio of said Cl.sub.2 etchant to said first mixture;
• and
• a second etching step, said second etching step etches at least partially through said aluminum-containing layer using a second source gas composition, said second source gas composition consisting essentially of a Cl.sub.2 etchant and a second mixture, said second mixture consisting essentially of HCl and CHF.sub.3, said second source gas composition having a second flow ratio of said Cl.sub.2 etchant to said second mixture different from said first flow ratio.