Chromeless phase shift mask
US7005217B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 2003 |
| Grant date | Feb 28, 2006 |
| Priority date | — |
| Expiry date | Feb 7, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70283
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photolithographic mask for receiving light at a wavelength, phase, and intensity and printing a desired image on a substrate with an optical system. The mask is formed on an optically transmissive substrate, called a mask blank. The mask blank is preferably one hundred percent transmissive of the light intensity at the wavelength. At least one layer of an attenuated material that is at least partially transmissive to the wavelength of the light is formed on the optically transmissive substrate. The at least one layer of the attenuated material preferably blocks from about fifty percent to about ninety-four percent of the intensity of the light at the wavelength, whereas the prior art masks use materials that block about six percent of the intensity of the light at the wavelength. The attenuated material defines three feature types on the mask, including a primary image having edges, a scattering bar disposed near the edges of the primary image, and a background region. The primary image represents the desired image to be printed on the substrate. The scattering bar is adapted to enhance a contrast of the primary image and to at least reduce the intensity of the light at the edges…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.