Double-mask photolithography method minimizing the impact of substrate defects

摘要

In the field of photolithography and, notably, photolithography in the extreme ultraviolet, a photolithography method is provided in which a first mask blank is produced that can have defects, an individual mapping of the positions of the defects of this mask blank is established using an inspection machine, and, for each defect, an exclusion zone is defined around the defect. Then, two complementary masks are produced, one with the first mask blank and with the desired design pattern, except in the exclusion zones, the latter being black, the other with a second mask blank and with the desired design pattern parts in the exclusion zones, all the rest of the second mask being black. The exposure of the surface to be processed by photolithography is done in two successive steps using the two complementary masks.

主权项

1. A photolithography method for a photolithography operation on a surface to be exposed according to a desired design pattern, the photolithography method comprising:
producing a first mask blank having defects; establishing an individual mapping of positions of the defects of the first mask blank using an inspection machine; defining an exclusion zone around each defect; patterning the first mask blank to form a first mask according to a first mask design comprising a desired design pattern except in the exclusion zones, the exclusion zones being black; producing a second mask blank; patterning the second mask blank to form a second mask according to a second mask design comprising a complementary design pattern comprising, in zones associated with and having a same position as the exclusion zones of the first mask, portions of the desired design pattern, the rest of the second mask design being black; and performing a fist photolithography step on the surface to be exposed using the first mask and a second photolithography step using the second mask by superposing, on the surface to be exposed, the exclusion zones of the first mask design and the associated zones of the second mask design, wherein the first and second masks are securely simultaneously attached to one and the same support such that the first and second masks can be used successively to perform said first and second photolithography steps.