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.

Photomask blank, photomask and its method for manufacturing

Abstract: PROBLEM TO BE SOLVED: To provide a phase shift mask blank which can reduce its machining processes without sacrificing its precision, and its method for manufacturing. SOLUTION: The phase shift section is a dug-down section having a predetermined depth from the surface of the light transmissive plate so as to produce a phase difference in the exposing light passing through the non-phase shifting area of the light transmissive plate. The light transmissive plate surface to form the dug-down section has an etching mask film 10 made of a material substantially dry-etched by a chlorine based gas but not by a fluoride based gas and functioning as an etching mask at least until the digging reaches the depth when forming the dug-down section by dry-etching, and a light shading film made of a material mainly consisting of tantalum on the surface of this etching mask film and simultaneously removed when dry-etching to form the dug-down section on the light transmissive plate. COPYRIGHT: (C)2010,JPO&INPIT

Phase shift mask blank and phase shift mask

Abstract: PROBLEM TO BE SOLVED: To provide a phase shift mask blank and a phase shift mask with high performance and little changes in the optical characteristics even for long- term use. SOLUTION: In the phase shift mask blank having at least one layer of a phase shift film essentially comprising a metal and silicon on a transparent substrate, a cap layer essentially comprising a metal and silicon is formed on the phase shift film. Durability against an excimer laser is imparted to the phase shift mask having the cap layer so that the phase shift mask blank and the phase shift mask have high quality and do not change in the optical characteristics even when the blank or the mask are irradiated with excimer laser light for a long time. COPYRIGHT: (C)2002,JPO

Method for phase shift mask design, fabrication, and use

Abstract: A system and method of strong phase-shifting a beam from an actinic light source in a lithographic process includes focusing a beam from the electromagnetic beam source onto a mask adapted to selectively phase-shift at least a portion of the beam according to a predetermined pattern. The beam is passed from the actinic light source through the mask producing a phase-shifted beam, and the phase-shifted beam is directed at a substrate such as a semiconductor wafer adapted to be selectively etched according to the predetermined pattern. The strong phase-shift serves to substantially eliminate zero-order light in the phase-shifted beam. Strong phase-shift mask techniques, through a two electromagnetic beam interference imaging process, are known in the art of microlithography to form imaging results for features of a size well below the limit of conventional prior art imaging.

Investigation of polarization effects on new mask materials

Abstract: As microlithography moves to smaller critical dimensions, structures on reticles reach feature sizes comparable to the operating wavelength. Furthermore, with increasing NA the angle of incidence of light illuminating the mask steadily increases. In particular for immersion lithography this will have severe consequences on the printing behavior of reticles. Polarization effects arise which have an impact on, among other things, the contrast of the printed image. Angular effects have to be considered when aggressive off-axis illumination schemes are used. Whereas numerous articles have been published on those effects and the underlying theory seems to be understood, there is a strong need for experimental verification of properties of real masks at the actinic wavelength. This paper presents measurements of polarization effects on different mask blank types produced at Schott Lithotec including chrome and alternative absorber binary mask blanks, as well as phase shift mask blanks. Thickness and optical dispersion of all layers were determined using grazing incidence x-ray reflectometry (GIXR) and variable angle spectroscopic ellipsometry (VASE). The set of mask blanks was patterned using a special design developed at the Advanced Mask Technology Center (AMTC) to allow measurements at different line width and pitch sizes. VUV Ellipsometry was then used to measure the properties of the structured materials, in particular the intensities in the 0th and 1st diffraction order for both polarization directions and varying angle of incidence. The degree of polarization of respective mask types is evaluated for dense lines with varying pitches and duty cycles. The results obtained experimentally are compared with simulations based on rigorous coupled wave analysis (RCWA).© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.