Dual damascene process using a single photo mask

摘要

A dual damascene process using a single photo mask in which a photo mask having patterns with different transparency is applied. A mask layer with a dual layer opening is formed first and then serves as an etching mask to form a dual opening in the dielectric layer. Then a metal layer is filled in the dual layer opening in the dielectric layer to form a dual damascene structure. Therefore, only a single photolithography process is necessary and overlay due to misalignment can be avoided.