Phase-shift mask

About: Phase-shift mask is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 18058 citations.

Direct phase-shift measurement with transmitted deep-UV illumination

Abstract: This paper describes a direct phase-shift measurement system with transmitted deep-UV illumination for phase shifting mask (PSM) using a lateral shearing interferometer system. This interferometer has new structure developed for this purpose. The mirror mount of the interferometer is made of SiC ceramics that promote stability against vibration and ambient temperature drift. The illumination employs a xenon mercury arc lamp that has a spectrum close to the wavelength of KrF excimer laser. The repeatability of measurements is 0.5 degree in 3 sigma. The system can measure a small pattern down to 1 μm with an alternating type PSM with the objective of N.A.=0.4. Influence of incident angle of illumination on phase-shift measurement is investigated by experiment. The results show similar effects with simulation for circular illumination. The phase-shift measurement results on quartz step meet well with a calculation from step height and known refractive index including the effect of incident angle of illumination. The deep-UV measurement results also have good correlation with calculations from the results with another direct phase-shift measurement system that wavelength is 365nm. The simulation for focus latitude of alternating type PSMs agree with the experimental results of wafer exposure and the phase measurement. The accuracy of this system is sufficient for application to development of phase shift mask process.

Phase shift mask blank and phase shift mask

Abstract: PROBLEM TO BE SOLVED: To adjust the internal stress of a semitransparent film a suitable range in state where the resistance to acid, the resistance to alkali and the resistance to impinging excimer laser of the semitransparent film formed in a phase shift mask blank or the like are improved. SOLUTION: The phase shift mask blank of halftone type has the semitransparent film with at least one layer of a thin film including silicon, nitrogen and/or oxygen formed on a transparent substrate, and is used for exposure light with a center wavelength not longer than 248 nm. The surface of the semitransparent film is precisely formed so that the surface roughness is not more than 0.3 nm in Ra. COPYRIGHT: (C)2002,JPO

Photolithography method, photolithography mask blanks, and method of making

Abstract: The invention provides optical projection lithography methods, photolithography photomasks, and optical photolithography mask blanks for use in optical photolithography systems utilizing deep ultraviolet light (DUV) wavelengths below 300 nm, such as DUV projection lithography systems utilizing wavelengths in the 248 nm region and the 193 nm region. The invention provides improved production of lithography patterns by inhibiting polarization mode dispersion of lithography light utilizing low birefringence mask blanks and photomasks.

Method and apparatus for repairing an alternating phase shift mask

Abstract: A method and apparatus for correcting phase shift defects in a photomask is provided by scanning the photomask for the defect and determining locations of at least one defect. Following the determination of the location of a defect, the defect is three-dimensionally analyzed producing three-dimensional results. Utilizing the three-dimensional results, a focus ion beam (FIB) is directed onto the defect to eliminate the defect. The FIB is controlled by an etch map which is generated based on the three-dimensional results. To provide further precision to the repairing of the photomask, test patterns of the FIB are generated and three-dimensionally analyzed. The three-dimensional test pattern results are further utilized in generating the etch map to provide greater control to the FIB.

Photomask blank, photomask, and methods of manufacturing the same

Abstract: A photomask blank is for manufacturing a phase shift mask having a light-transmitting substrate provided with a phase shift portion adapted to give a predetermined phase difference to transmitted exposure light. The phase shift portion is a dug-down part that is dug down from a surface of the light-transmitting substrate to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through the light-transmitting substrate at a portion where the phase shift portion is not provided. The photomask blank includes, on the digging-side surface of the light-transmitting substrate, an etching mask film that is made of a material being dry-etchable with a chlorine-based gas, but not dry-etchable with a fluorine-based gas, and serves as an etching mask at least until, when forming the dug-down part by dry etching, the dry etching reaches the digging depth. The photomask blank further includes, on a surface of the etching mask film, a light-shielding film that is made of a material mainly containing tantalum and has a thickness so as to be removable during the dry etching for forming the dug-down part of the light-transmitting substrate.