Method and structure for lithography alignment

A method for lithography alignment, comprising:

• providing a first structure comprising a substrate and a mask layer located at a side of the substrate, wherein a first pattern in the mask layer comprises a first groove, a second pattern in the mask layer comprises a second groove, and the second pattern serves as an alignment mark for lithography;
• forming a metal layer, wherein the metal layer fills the first groove fully and covers a sidewall and a bottom surface of the second groove, and a thickness of the metal layer at the bottom surface of the second groove is less than a depth of the second groove;
• forming a first non-transparent layer at a side of the metal layer away from the substrate, wherein a surface of the first non-transparent layer away from the substrate has a first recess, and an orthographic projection of the first recess on the substrate is located within an orthographic projection of the second groove on the substrate;
• forming a photoresist layer at a side of the first non-transparent layer away from the substrate, wherein a surface of the photoresist layer away from the substrate is parallel to a surface of the substrate;
• and
• forming a second non-transparent layer at a side of the photoresist layer away from the substrate, wherein a surface of the second non-transparent layer away from the substrate is parallel to the surface of the substrate.