Fabry–Pérot structures for attenuated phase-shifting mask application in ArF and F2 lithography

Abstract

Articles you may be interested inHigh reflectance of reflective-type attenuated-phase-shifting masks for extreme ultraviolet lithography with high inspection contrast in deep ultraviolet regimes Correlation between the chemical compositions and optical properties of AlSi x N y embedded layer for attenuated phase-shifting mask in 193 nm and the modification of the R-T method for measuring n and kWe demonstrate a structure for an attenuated phase-shifting mask ͑APSM͒ which is based on a three-layer Fabry-Pérot structure for ArF ͑193 nm͒ and F 2 (157 nm) excimer laser based lithographies. The APSM structure is composed of a metal/dielectric/metal stack. The optical characteristics of the Fabry-Pérot structure meet the following requirements: 180°phase shift, transmittance in the range of 4%-15%, reflectance of less than 10% at the exposure wavelength, and high inspection contrast at the inspection wavelength. Common dielectric and metal materials, such as chromium, tungsten, amorphous silicon, silicon dioxide, aluminum oxide, and aluminum nitride films, can be used to construct the Fabry-Pérot structure. The top metal layer can also prevent charge accumulation during electron-beam writing.