Embedded phase shifting mask with improved relative attenuated film transmission
US5618643A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1995 |
| Grant date | Apr 8, 1997 |
| Priority date | — |
| Expiry date | Dec 15, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/32
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus for fabricating a mask for use in patterning a radiation sensitive layer in a lithographic printer. An embedded phase shifting layer is disposed over a substantially transparent base layer such that attenuated regions of the mask are phase shifted approximately 160 to 200 degrees relative to open features in the mask. In accordance with the present invention, radiation transmission is reduced through the open feature regions of the mask. In one embodiment, a thin radiation transmission reducing layer is deposited over the open feature regions of the mask. In another embodiment, the open feature regions of the mask are roughened to reduce radiation transmission. In yet another embodiment, ion implantation is performed in the open feature regions of the mask to reduce transmission. With the reduced transmission of radiation through the open feature regions of the present mask, high resolution lithography employing short wavelength radiation is realized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.