Mask blank, phase shift mask, and method of manufacturing semiconductor device
US11720014B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2020 |
| Grant date | Aug 8, 2023 |
| Priority date | — |
| Expiry date | Sep 26, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/0337
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The phase shift film has a function to transmit an exposure light of a KrF excimer laser at a transmittance of 2% or more, and a function to generate a phase difference of 150 degrees or more and 210 degrees or less between the exposure light transmitted through the phase shift film and the exposure light transmitted through the air for a same distance as a thickness of the phase shift film, in which the phase shift film has a structure where a lower layer and an upper layer are stacked in order from a side of the transparent substrate, in which a refractive index nL of the lower layer at a wavelength of the exposure light and a refractive index nU of the upper layer at a wavelength of the exposure light satisfy a relation of nL>nU, in which an extinction coefficient kL of the lower layer at a wavelength of the exposure light and an extinction coefficient kU of the upper layer at a wavelength of the exposure light satisfy a relation of kL>kU; and in which a thickness dL of the lower layer and a thickness dU of the upper layer satisfy a relation of dL<dU.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.