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.

Transparent resins for 157-nm lithography

Abstract: The development of sufficiently transparent resin systems is one of the key elements required for a successful and timely introduction for 157 nm lithography. This paper reports on the Simple Transmission Understanding and Prediction by Incremental Dilution (STUPID) model, a quick back-of-the-envelope increment scheme to estimate the absorption of polymers at 157 nm. A number of promising candidate resins based on norbornenes are discussed, and results with a first 157 nm resin system developed at the University of Austin are presented. The new system is based on copolymers of norbornene-5-methylenehexafluoroisopropanol (NMHFA) and t-butyl norbornene carboxylate (BNC), formulated with an acetal additive obtained by copolymerization of t-butyl norbornene-5-trifluoromethyl-5-carboxylate (BNTC) with carbon monoxide. Lithographic performance of this system extends to 110 nm dense features using standard illumination and a binary mask, or 80 nm semi-dense and 60 nm isolated features with a strong phase shift mask. The dry etch resistance of this resist is found to be slightly lower than APEX-E DUV resist for polysilicon but superior to it for oxide etches.

Alternating Phase Shift Mask in Extreme Ultra Violet Lithography

Abstract: Pattern printability by alternating phase shift mask (alt-PSM) is discussed by simulation. The alt-PSM with an additive structure that provides a completely flat surface structure on a multilayer mask blank is considered. The additive structure is constituted of Si, Ru, TaN and Mo materials that have been generally used for binary masks in extreme ultraviolet lithography so far. The alt-PSM has sufficient capability to resolve an 18 nm line pattern on a wafer due to strong resolution enhancement. Pattern edge contrast of an aerial image by the alt-PSM becomes 1.5 times larger than that by the conventional binary mask. Depth of focus of the alt-PSM increases up to 300 nm that is three times larger than that of the binary mask. The mask error enhanced factor becomes small and changes gradually with defocusing. The alt-PSM enhances pattern edge contrast even for dense lines at a large angle of the off-axis incident light of 7.05 deg.

Phase shift mask and method for manufacturing the same, and method for manufacturing integrated circuit

Abstract: A phase shift mask is provided which includes: a substrate that is transparent to irradiation light, a shielding region formed on the substrate and in which a line pattern is formed, and a first transparent region and a second transparent region located on respective opposite sides of the shielding region on the substrate, wherein a phase shifter is formed under the first transparent region, and the phase shifter has a side wall including an outward protruding bent portion. The phase shifter can be formed by, for example, irradiating and scanning a predetermined region of the substrate with femtosecond pulse laser light applied from above the substrate.

Practical phase control technique for alternating phase-shift mask fabrication

Abstract: Techniques of fabricating altPSMs of single trench structure by quartz etching have been developed. A two-step etching process was adopted to make the side-etching structure. Shifter areas were etched by dry-method in first step and by wet-method in second step. In the experiments, by a RIE type dry-etching machine, a hydrofluoric (HF) acid etching system, a phase measurement system and 6025-mask plate were used. We optimized dry-etching parameter, such as pressure, RF power and composition of gas mixture ratio. The smallest phase difference between the device-pattern and the monitor- pattern was obtained in smallest phase difference between the device-pattern and the monitor-pattern was obtained in low pressure wit inactive gas. The dry etching uniformity was improved and range value was reduced from 2.7 degrees to 1.1 degrees by using type B of the plate holder. In wet etching process, two modes of movement and two concentration of buffered HF acid were compared from the viewpoint of etching uniformity. The uniformity was reduced to two third of the benchmark condition. For AltPSMs production quality, phase mean deviation is within +/- 2 degrees and uniformities are within 2.5 degrees. The technique described in this study can be applied to 150 nm node altPSMs fabrication and shows an extensibility to 130 nm node.

Method of making a twin alternating phase shift mask

Abstract: A photolithographic mask comprises a first plurality of image segments etched into a mask substrate to a first level imparting a predetermined phase shift with respect to electromagnetic radiation of a predetermined frequency, preferably a 90° phase shift, and a second plurality of image segments etched into the mask substrate to a second level imparting a phase shift of 180° more or less than the phase shift of the first plurality of image segments with respect to the predetermined electromagnetic radiation, preferably a 270° phase shift. The first and second segments are disposed adjacent each other on a substrate and positioned such that an intersection of the predetermined electromagnetic radiation passing through the segments causes printable images to be created below the substrate when exposed to the predetermined electromagnetic radiation. The mask may further include a blocking material for the electromagnetic radiation, adjacent at least one of the first and second segments or regions, of a configuration adapted to cause a printable image to be created below the mask when exposed to the predetermined electromagnetic radiation.