Interconnect Structure for Semiconductor Devices

A method of forming a semiconductor device, the method comprising:

• forming a first conductive feature in a first dielectric layer;
• forming a second dielectric layer over the first dielectric layer;
• forming an opening in the second dielectric layer to exposes an upper surface of the first conductive feature, wherein forming the opening comprises performing an anisotropic plasma etching process;
• after forming the opening, treating the first conductive feature with a plasma process different from the anisotropic plasma etching process;
• and
• after the plasma process, cleaning the opening using deionized water, wherein the cleaning enlarges a bottom portion of the opening.

A method of forming a semiconductor device, the method comprising:

• forming a first conductive feature in a first dielectric layer disposed over a substrate;
• forming a second dielectric layer over the first dielectric layer;
• etching the second dielectric layer to form an opening in the second dielectric layer, wherein the first conductive feature is exposed at a bottom of the opening;
• after the etching, treating the first conductive feature with a plasma process, wherein the plasma process converts an upper portion of the first conductive feature into a first material;
• after the plasma process, cleaning the opening by a wet cleaning process, wherein the wet cleaning process comprises a wet cleaning step using deionized water, wherein the deionized water removes the first material and enlarges the bottom of the opening;
• and
• after the cleaning, filling the opening with an electrically conductive material.