System and method for dark field inspection

A method for fabricating a semiconductor structure, comprising:

• providing a substrate and a patterned layer formed on the substrate, one or more overlay marks being formed on the patterned layer;
• performing a pre-film-formation overlay inspection using a bright field (BF) inspection mode of an inspection tool to receive a pre-film-formation data on the one or more overlay marks on the patterned layer;
• forming a first layer on the patterned layer;
• performing a first overlay inspection using a dark field (DF) inspection tool to receive a first data on the one or more overlay marks underlying the first layer;
• and
• determining whether the pre-film-formation data matches the first data.

A method for fabricating a semiconductor structure, comprising:

• providing a substrate and a patterned layer formed on the substrate, one or more overlay marks being formed on the patterned layer;
• performing a pre-film-formation overlay inspection using a bright field (BF) inspection tool to receive a pre-film-formation data on the one or more overlay marks;
• forming a first layer on the patterned layer;
• performing a post-film-formation overlay inspection using the BF inspection tool to receive a first post-film-formation data on the one or more overlay marks;
• determining whether the pre-film-formation data matches the first post-film-formation data;
• and
• when the pre-film-formation data does not match the first post-film-formation data, performing a second post-film-formation overlay inspection using a dark field (DF) inspection tool to receive a second post-film-formation data on the one or more overlay marks.