US Patent 9859206 Photoactive compound gradient photoresist

A system and method for forming photoresists over semiconductor substrates is provided. An embodiment comprises a photoresist with a concentration gradient. The concentration gradient may be formed by using a series of dry film photoresists, wherein each separate dry film photoresist has a different concentration. The separate dry film photoresists may be formed separately and then placed onto the semiconductor substrate before being patterned. Once patterned, openings through the photoresist may have a tapered sidewall, allowing for a better coverage of the seed layer and a more uniform process to form conductive materials through the photoresist.