Attenuating phase-shift mask structure and fabrication method
US5503951A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1995 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Apr 17, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/38
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An attenuating, phase-shift, semiconductor fabrication mask having recessed attenuating and phase-shifting regions that is not susceptible to phase defects in the printing regions of the mask. This desirable result is accomplished by not altering the surface of the fully transmissive regions of the mask and by recessing the attenuating regions of the mask relative to the fully transmissive regions. A method of forming the recessed attenuated phase-shift mask is also included. The process begins by forming recesses in the regions of the mask substrate where phase-shifting is desired and back filling these recessed regions with a selected thickness of attenuating material so that the attenuation effect of the deposited material together with the depth of the recess co-act to shift the light approximately 180.degree. (.pi. radians) from the light transmitted through the adjacent transmissive regions of the mask to create by destructive interference a sharp delineation at the edges of the projected mask image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.