Method of doping metal layers for electromigration resistance

A process for forming aluminum-copper alloy interconnect lines on an integrated circuit which comprises the steps of:

• (a) depositing a substantially pure aluminum film onto a semiconductive surface of an integrated circuit;
• (b) etching said aluminum film to remove portions of said aluminum film and expose portions of said semiconductive surface while also providing a selected pattern of remaining aluminum film;
• (c) depositing copper in a doping amount upon all of said remaining aluminum film without depositing any copper upon portions of said exposed semiconductive surface wherein aluminum film is not present;
• and
• (d) heating the structure resulting from steps (a)-(c) to diffuse copper throughout said aluminum film, thus providing said aluminum-copper alloy interconnect lines in said selected pattern.

A process for forming aluminum-copper alloy interconnect lines on an integrated circuit which comprises the steps of:

• (a) depositing a substantially pure aluminum film which is not aluminum-copper alloy onto a semiconductor surface of an integrated circuit;
• (b) etching said aluminum film to remove portions of said aluminum film and to expose portions of said semiconductor surface, while also providing a selected pattern of remaining aluminum film;
• (c) depositing copper by metallo-organic chemical vapor deposition in a doping amount upon all of said remaining aluminum film without depositing any copper upon portions of said exposed semiconductor surface wherein aluminum film is not present;
• and
• (d) heating the structure resulting from steps (a)-(c) to diffuse copper throughout said remaining aluminum film, to provide said aluminum-copper alloy interconnect lines.