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.

Chromeless phase shift mask

Abstract: A photolithographic mask for receiving light at a wavelength, phase, and intensity and printing a desired image on a substrate with an optical system The mask is formed on an optically transmissive substrate, called a mask blank The mask blank is preferably one hundred percent transmissive of the light intensity at the wavelength At least one layer of an attenuated material that is at least partially transmissive to the wavelength of the light is formed on the optically transmissive substrate The at least one layer of the attenuated material preferably blocks from about fifty percent to about ninety-four percent of the intensity of the light at the wavelength, whereas the prior art masks use materials that block about six percent of the intensity of the light at the wavelength The attenuated material defines three feature types on the mask, including a primary image having edges, a scattering bar disposed near the edges of the primary image, and a background region The primary image represents the desired image to be printed on the substrate The scattering bar is adapted to enhance a contrast of the primary image and to at least reduce the intensity of the light at the edges of the primary image The background region is adapted to block the light without using a material that is non transmissive to the light, such as chrome By “block the light” it is meant that the background region substantially and preferably reduces the intensity of the light passing through the background region to about zero

Methods of determining processing alignment in the forming of phase shift regions

Abstract: In but one implementation in the fabrication of a phase shift mask, both process alignment in the formation of a phase shift alignment region and degree of phase shift of the phase shift alignment region is determined at least in part by using aerial image measurement equipment. In one implementation, aerial image measurement equipment is used to both determine phase shift of a phase shift alignment region at least in part by capturing a series of aerial images as a function of focus and to determine process alignment in the formation of the phase shift alignment region at least in part by measuring distance between spaced low intensity locations defined by an edge of the phase shift alignment region and an adjacent alignment feature edge. In one implementation, process alignment in the formation of a phase shift alignment region is determined at least in part by using aerial image measurement equipment to determine photoresist patterning alignment prior to etching material to form said phase shift alignment region. In one implementation, aerial image measurement equipment is used to determine photoresist patterning alignment for formation of a phase shift alignment region at least in part by measuring distance between spaced intensity change locations defined by an alignment feature edge beneath the photoresist and an edge of the photoresist.

Method for manufacturing phase shift mask blank, method for manufacturing phase shift mask, and method for transferring pattern

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a phase shift mask blank having a light translucent film or a light translucent portion having the designated phase angle and transmittance and being superior in film characteristics such as chemical resistance, light resistance, and internal stress. SOLUTION: The method for manufacturing a halftone phase shift mask blank having a translucent film on a transparent substrate comprises: forming a translucent film containing nitrogen, metal and silicon and having a compressive stress on a transparent substrate by sputtering a target containing 70 to 95 mol% silicon and metal in an atmosphere containing nitrogen on the transparent substrate; and heat treating the translucent film at a temperature higher than a baking temperature of a resist film to be formed on the translucent film so as to reduce the internal stress of the translucent film. COPYRIGHT: (C)2009,JPO&INPIT

Improved imaging properties of thin attenuated phase shift masks for extreme ultraviolet lithography

Abstract: The mask shadowing effect is a unique phenomenon caused by a mirror-based mask structure and an oblique incident angle of light in the extreme ultraviolet lithography process. This results in a horizontal–vertical (H–V) bias, an ellipticity in the contact hole pattern and, eventually, a patterning limit and critical dimension (CD) nonuniformity. Reducing the absorber thickness is the most effective method to minimize the mask shadowing effect, but this can deteriorate the mask image contrast. In this paper, an attenuated phase shift mask (PSM) is proposed as a potential method for extending the patterning limit to below 16 nm. By applying Mo as a phase shift layer, which has a refractive index (n) similar to that of the TaN absorber but with a lower absorption value, thin attenuated PSMs with various reflectivity values were obtained by controlling the Mo thickness. The proposed PSM consists of a 16.5-nm-thick TaN absorber layer and a 24-nm-thick Mo phase shifter on 2-nm-thick Ru-capped Mo/Si multilayers. This attenuated PSM results in 17.98% and 27.52% reductions in the mask error enhancement factor as well as 3.65 and 1.84 nm reductions in the H–V CD bias compared with the conventional binary intensity mask with a 70-nm-thick TaN absorber for the 22 nm line and space 1:1 vertical dense pattern under 0.25 and 0.33 numerical aperture illumination conditions, respectively. Moreover, a 10%–12% improved image contrast was obtained with 11%–17% reflectivity on the absorber stack, which corresponds to a 24–29 nm Mo thickness under 0.25 NA illumination conditions.

Phase shift mask and phase shift mask blanks as well as production of phase shift mask blank

Abstract: PURPOSE:To provide the phase shift mask and phase shift mask blank which have the good adhesion of the films formed on a substrate and high productivity and are usable for use with an exposing device using the short wavelength of a KrF excimer laser, etc., as a light source as well as the process for production of the phase shift mask blank. CONSTITUTION:This phase shift mask is constituted by successively providing the surface of the transparent substrate 1 with an etching stopper layer 2 consisting of the nitride or carbide of silicon, a phase shift layer 3 consisting of the oxide of silicon, a light shielding layer 4 mainly consisting of the silicon and an antireflection layer 5 consisting of the nitride or carbide of the silicon and respectively patterning 3', 4'' the phase shift layer 3 and the light shielding layer 4. The phase shift mask blank is constituted by providing the layers before the patterning. This process for production of the phase shift mask blank consists in continuously forming the thin films of the respective layers by a sputtering method, etc., within the same chamber on the transparent substrate 1.