Patent · US Active

Phase shift masks for extreme ultraviolet lithography

US11487197B2 · kind B2 · utility

0Cited by
3References
20Claims
0Family size

Assignee

Inventors

Key dates

Filing dateDec 14, 2020
Grant dateNov 1, 2022
Priority date—
Expiry dateMay 25, 2041

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG03F1/54
  • WIPO fieldOptics
  • WIPO sectorInstruments

Abstract

Phase shift masks for an extreme ultraviolet lithography process includes a substrate, a reflection layer on the substrate, a capping layer on the reflection layer, and phase shift patterns on the capping layer. Each of the phase shift patterns may include a lower absorption pattern on the capping layer and an upper absorption pattern on the lower absorption pattern. A refractive index of the upper absorption pattern may be higher than a refractive index of the lower absorption pattern, and a thickness of the upper absorption pattern is smaller than a thickness of the lower absorption pattern.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.