Aluminum-copper alloy evaporated films with low via resistance

A method of fabricating thin film interconnected metallization on a dielectric coated integrated circuit substrate having ohmic contact via openings through said dielectric to elements of said circuit, comprising:

• forming a vacuum environment about said substrate;
• heating said substrate in said vacuum environment to between about 180.degree. C. to about 200.degree. C. to condition said substrate for deposition of first level metallization film;
• discontinuing said heating and coincidently initiating evaporation of said first level metallization to deposit, during cooling of said substrate, a first aluminum-copper metal film over said dielectric and in said ohmic contact via openings;
• defining in said first metallization film a predetermined interconnection pattern to said circuit elements;
• depositing a dielectric layer over said first metallization level and said dielectric coating;
• forming a second pattern of via openings in said dielectric layer to expose selected portions of said first metallization pattern;
• dry etching to sputter clean said exposed first level metallization pattern and said dielectric layer in an inert atmosphere and at ambient temperatures;
• initiating evaporation of a second level aluminum-copper film at ambient temperatures over said dielectric layer and in said second vias and
• coincidentally initiating heating of said substrate to a temperature in the range of about 150.degree. C. to about 200.degree. C. over the deposition time of said evaporation of said second level metallization.