System and method for lithography alignment

摘要

The present disclosure provides one embodiment of a lithography system for integrated circuit making. The system includes a substrate stage designed to secure a substrate and being operable to move the substrate; an alignment module that includes a tunable light source being operable to generate an infrared light with a wavelength tunable; and a detector to receive the light; and an exposing module integrated with the alignment module and designed to performing an exposing process to a resist layer coated on the substrate.

主权项

1. A method, comprising:
providing an integrated circuit (IC) substrate having a first alignment mark, a second alignment mark, and a first circuit pattern defined in a first pattern layer and a third alignment mark, a fourth alignment mark, and a second circuit pattern defined in a second pattern layer; illuminating the first and second alignment marks, through a photomask, with a first light to determine a first layer alignment error including a first alignment error in relation to the first alignment mark and a second alignment error in relation to the second alignment mark, wherein the first alignment error has more weight than the second alignment error; illuminating the third and fourth alignment marks, through the photomask, with a second light to determine a second layer alignment error including a third alignment error in relation to the third alignment mark and a fourth alignment error in relation to fourth alignment mark, wherein the third alignment error has more weight than the fourth alignment error; determining a collective alignment error including the first layer alignment error in relation to the first circuit pattern and the second layer alignment error in relation to the second circuit pattern; and adjusting alignment between the IC substrate and the photomask to minimize the collective alignment error.