The phase-shifting mask consists of a normal transmission mask that has been coated with a transparent layer patterned to ensure that the optical phases of nearest apertures are opposite. Destructive interference between waves from adjacent apertures cancels some diffraction effects and increases the spatial resolution with which such patterns can be projected. A simple theory predicts a near doubling of resolution for illumination with partial incoherence σ < 0.3, and substantial improvements in resolution for σ < 0.7. Initial results obtained with a phase-shifting mask patterned with typical device structures by electron-beam lithography and exposed using a Mann 4800 10× tool reveals a 40-percent increase in usuable resolution with some structures printed at a resolution of 1000 lines/mm. Phase-shifting mask structures can be used to facilitate proximity printing with larger gaps between mask and wafer. Theory indicates that the increase in resolution is accompanied by a minimal decrease in depth of focus. Thus the phase-shifting mask may be the most desirable device for enhancing optical lithography resolution in the VLSI/VHSIC era.

Improving resolution in photolithography with a phase-shifting mask

Plasma etching technologies such as reactive ion etching (RIE), isotropic etching, and ashing/plasma cleaning are the currently used booster technologies for manufacturing all silicon devices based on the scaling law. The needs-driven conversion from the wet etching process to the plasma/dry etching process is reviewed. The progress made in plasma etching technologies is described from the viewpoint of requirements for the manufacturing of devices. The critical applications of RIE, isotropic etching, and plasma ashing/cleaning to form precisely controlled profiles of high-aspect-ratio contacts (HARC), gate stacks, and shallow trench isolation (STI) in the front end of line (FEOL), and also to form precise via holes and trenches used in reliable Cu/low-k (low-dielectric-constant material) interconnects in the back end of line (BEOL) are described in detail. Some critical issues inherent to RIE processing, such as the RIE-lag effect, the notch phenomenon, and plasma-induced damage including charge-up damage are described. The basic reaction mechanisms of RIE and isotropic etching are discussed. Also, a procedure for designing the etching process, which is strongly dependent on the plasma reactor configuration, is proposed. For the more precise critical dimension (CD) control of the gate pattern for leading-edge devices, the advanced process control (APC) system is shown to be effective.

https://iopscience.iop.org/article/10.1143/JJAP.47.1435/pdf

Developments of Plasma Etching Technology for Fabricating Semiconductor Devices

A photomask blank is provided comprising an etch stop film which is disposed on a transparent substrate and is resistant to fluorine dry etching and removable by chlorine dry etching, a light-shielding film disposed on the etch stop film and including at least one layer composed of a transition metal/silicon material, and an antireflective film disposed on the light-shielding film. When the light-shielding film is dry etched to form a pattern, pattern size variation arising from pattern density dependency is reduced, so that a photomask is produced at a high accuracy.

Photomask blank and photomask

A light-shielding film 2 is formed on a transparent substrate 1. A hard mask film 3 is formed on this light-shielding film 2. The entire hard mask film 3 is made of a chromium-containing material including tin. The film made a chromium-containing material including tin can cause a significant increase in the etching rate at the time of chlorine-containing dry etching. Furthermore, comparing with a film made of a chromium-containing material in which part of chromium is replaced with a light element, the above film has an equal or higher level of etching resistance to fluorine-dry etching. Thus, burden on a photoresist at the time of etching the chromium-containing material film can be reduced. Therefore, high-precision pattern transfer can be performed even in the case that the resist film is thinned.

Photomask blank and method for manufacturing photomask

A light-shieldable film (12) is formed on one principal plane of an optically transparent substrate (11), and the light-shieldable film (12) has a first light-shieldable film (13) and a second light-shieldable film (14) overlying the first light-shieldablefilm (13). The first light-shieldable film (13) is a film that is not substantially etched by fluorine-based(F-based)dry etching and is primarily composed of chromium oxide, chromium nitride, chromium oxynitride or the like. The second light-shieldable film (14) is a film that is primarily composed of a silicon-containing compound that can be etched by F-based dry etching, such as silicon oxide, silicon nitride, silicon oxynitride, silicon/transition-metal oxide, silicon/transition-metal nitride or silicon/transition-metal oxynitride.

Photomask blank, photomask and fabrication method thereof

PROBLEM TO BE SOLVED: To provide a technique capable of easily and accurately adjusting the wavelength dependence of reflectance of a light shielding film so as to properly and rapidly perform redesigning under transition of exposure wavelength, resist drawing wavelength, and inspection wavelength in a halftone phase shift mask. SOLUTION: In a method for adjusting the wavelength dependence of reflectance of the light shielding film 3 in the halftone phase shift mask blank having on a transparent substrate 1 a translucent film 2 having a prescribed transmittance and phase shifting extent to exposure light and the light shielding film 3 formed on on the translucent film 2, the top layer part of the light shielding film 3 is formed as a reflectance adjustment part 3a comprising chromium, carbon, oxygen, and nitrogen and the wavelength dependence of reflectance of the entire light shielding film 3 is adjusted according to the nitrogen content of the reflectance adjusting part 3a. COPYRIGHT: (C)2005,JPO&NCIPI

Method for producing halftone phase shifting mask blank

PURPOSE: To prevent the degradation in sectional shape at the time of overetching by incorporating a chromium carbide, chromium nitride and chromium oxide into an antireflection film and decreasing the degree of oxidation of the antireflection film from a light transparent substrate toward a light shieldable thin film in the thickness direction thereof. CONSTITUTION: The 1st antireflection film 2 consists of the chromium carbonitrooxides and the degree of the oxidation thereof decreases from the light transparent substrate 1 toward the light shieldable thin film 3 in the thickness direction thereof. The degree of the oxidation of the antireflection film 2 is changed in the film thickness direction, by which the side etching rate is suppressed and the prescribed sectional shape is obtd. The etching rate of the antireflection film 2 is matched with the etching rate of the light shieldable thin film 3 laminated thereon by carbonizing the chromium. The formation of the film to the overhang-like sectional shape is prevented in this way. COPYRIGHT: (C)1992,JPO&Japio

In obtaining a photomask blank 1 by disposing a sputtering target in a vacuum chamber and forming thin films 3, 4, and 5 with a three-layer construction of CrN/CrC/CrON over a transparent substrate 2 by reactive sputtering, the thin films are formed in a mixed gas atmosphere containing helium, and the helium gas flux in the mixed gas is controlled such that the crystal grain diameter of the CrC thin film, which is the thickest film, will be 3 to 7 nm. This yields a photomask blank having thin films with low film stress, having good film quality, and which can be produced at a high yield in mass production.

Photomask blank, photomask, methods of manufacturing the same, and method of forming micropattern

PROBLEM TO BE SOLVED: To improve the dimensional accuracy of a halftone material film pattern of a halftone type phase shift mask manufactured by using a blank having a laminated structure of the halftone material film and a light shielding film. SOLUTION: The halftone type phase shift mask blank 1 having the halftone material film 3 on a transparent substrate 1 and the light shielding film consisting of a metallic film 4 and antireflection film 5 formed on the halftone material film 3 is formed by depositing the light shielding film in such a manner that the film thickness thereof attains a range from 50 to 77 nanometers. As a result, the difference in the film stress before and after the removal of the light shielding film is reduced in manufacturing the halftone type phase shift mask. COPYRIGHT: (C)2003,JPO

Halftone type phase shift mask blank and method of manufacturing halftone type phase shift mask blank

PROBLEM TO BE SOLVED: To decrease the film stress in a light shielding film containing a layer having an antireflective function in the manufacture of a photomask blank. SOLUTION: The photomask blank 1 comprises a light shielding film containing an antireflection film 5 having an antireflective function and formed on a transparent substrate 2. The light shielding film has a layered structure of a first light shielding film 3 made of chromium nitride and a second light shielding film 4 made of chromium carbide as well as the antireflection film 5. The light shielding film is deposited to 60 to 77 nm total film thickness. COPYRIGHT: (C)2003,JPO

Masao Ushida

Papers

Method for producing halftone phase shifting mask blank

Photomask blank and photomask

Photomask blank, photomask, methods of manufacturing the same, and method of forming micropattern

Halftone type phase shift mask blank and method of manufacturing halftone type phase shift mask blank

Photomask blank, photomask and method for manufacturing the same