Dai Nippon Printing Co., Ltd.

Mitsubishi Electric Corporation

Mitsubishi Electric Company

Renesas Technology Corp.

Hiroyuki Miyashita

Hiroshi Mohri

Masahiro Takahashi

Koichi Mikami

Yukio Iimura

Junji Fujikawa

Keiji Hashimoto

Hiroshi Fujita

Yoichi Takahashi

Naoya Hayashi

Sachiko Ishikita

Masa-aki Kurihara

Jiro Takei

Toshifumi Yokoyama

Norihiro Tarumoto

Keiji c/o Dai Nippon Printing Co Ltd Hashimoto

A halftone phase shift photomask having a sufficiently high transmittance for light of short wavelength and usable for high-resolution lithography effected by exposure using deep-ultraviolet+radiation, e.g., krypton fluoride excimer laser light. The halftone phase shift photomask has on a transparent substrate a halftone phase shift layer which includes at least one layer composed mainly of a chromium compound. The chromium compound contains at least fluorine atoms in addition to chromium atoms. A transmittance higher than a predetermined level can be obtained even in exposure carried out a relatively short wavelength. The photomask can be used for exposure using deep-ultraviolet+radiation, e.g., krypton fluoride excimer laser light (wavelength: 248 nm). Thus, high-resolution lithography can be realized. Since the photomask can be formed by approximately the same method as in the case of the conventional photomasks, it is possible to improve the yield and reduce the cost.

Halftone phase shift photomask, halftone phase shift photomask blank,

A halftone phase shift photomask having a sufficiently high transmittance for light of short wavelength and usable for high-resolution lithography effected by exposure using deep-ultraviolet+radiation, e.g., krypton fluoride excimer laser light. The halftone phase shift photomask has on a transparent substrate a halftone phase shift layer which includes at least one layer composed mainly of a chromium compound. The chromium compound contains at least fluorine atoms in addition to chromium atoms. A transmittance higher than a predetermined level can be obtained even in exposure carried out at a relatively short wavelength. The photomask can be used for exposure using deep-ultraviolet+radiation, e.g., krypton fluoride excimer laser light (wavelength: 248 nm). Thus, high-resolution lithography can be realized. Since the photomask can be formed by approximately the same method as in the case of the conventional photomasks, it is possible to improve the yield and reduce the cost.

A phase shift photomask capable of being produced by dry etching with adequate in-plane uniformity of pattern dimension even if there is a large difference in exposed area ratio between different areas on the mask. In a phase shift photomask having an area provided with a phase shift layer which practically shifts the phase relative to another area, a dummy etching pattern (13) for dry etch rate correction is provided in an area other than a pattern exposure area (9 and 10), or a dummy etching pattern for dry etch rate correction having a size less than the limit of resolution attained by transfer is provided in the pattern exposure area, thereby reducing the etch rate nonuniformity due to the pattern density variation in the process of dry etching the phase shift photomask, and thus providing a phase shift photomask of high accuracy.

Phase shift photomask and phase shift photomask dry etching method

The invention relates a halftone phase shift photomask and a blank therefor, which enables the transmittance of a phase shift portion to be varied even after blank or photomask fabrication, can accommodate to a variety of patterns, and can be fabricated on a mass scale. The exposure light transmittance of a halftone phase shift layer is arbitrarily variable within the range of 1% to 50%, inclusive, by exposing the blank or photomask to a high temperature elevated to at least 150.degree. C., to an oxidizing atmosphere, or to a reducing atmosphere at a step that can provided independent of the steps for film-forming or photomask fabrication step. This enables the exposure light transmittance of the halftone phase shift layer to be changed to any desired value after blank or photomask fabrication, and so an optimal halftone phase shift photomask to be obtained depending on the size, area, location, shape, and the like of the transferred pattern.

Blanks for halftone phase shift photomasks, halftone phase shift

The invention relates to a phase shift photomask in which the peripheral region portion of a phase shift layer is removed by a relatively simple procedure and which has no or little defect and is inexpensive, a blank therefor, and a process for fabricating them. The process includes the steps of forming phase shift layer 23 all over the surface of one side of transparent substrate 21, and immersing only the peripheral region of substrate 21 in etching solution 25 to etch away the peripheral region of phase shift layer 23, whereby phase shift layer 27 is confined within an area smaller than that of substrate 21.

Phase shift photomask, phase shift photomask blank, and process for

The present invention relates particularly to a process for producing phase shift layer-containing photomasks, which can produce phase shift photomasks through a reduced or limited number of steps to reduce or limit the incidence of phase shifter pattern deficiencies or other defects and at lower costs as well. For instance, a photomask blank of the structure that a substrate is provided thereon with an electrically conductive layer and a light-shielding thin film in this order is used to coat a starting material for spin-on-glass uniformly on a light-shielding pattern formed thereon. A pattern is directly drawn on the coaxed-spin-on-glass layer with energy beams emanating from electron beam exposure hardware, etc., and the substrate is developed with a solvent after pattern drawing with energy beams to wash off an excessive spin-on-glass portion other than the spin-on-glass layer irradiated with the ionizing radiations. Finally, the post-development substrate is baked to form a phase shifter pattern.

Phase shift layer-containing photomask, and its production and correction

The present invention relates particularly to a process for producing phase shift layer-containing photomasks, which can produce phase shift photomasks through a reduced or limited number of steps to reduce or limit the incidence of phase shifter pattern deficiencies or other defects and at lower costs as well. For instance, a photomask blank of the structure that a substrate is provided thereon with an electrically conductive layer and a light-shielding thin film in this order is used to coat a starting material for spin-on-glass uniformly on a light-shielding pattern formed thereon. A pattern is directly drawn on the coated spin-on-glass layer with energy beams emanating from electron beam exposure hardware, etc., and the substrate is developed with a solvent after pattern drawing with energy beams to wash off an excessive spin-on-glass portion other than the spin-on-glass layer irradiated with the ionizing radiations. Finally, the post-development substrate is baked to form a phase shifter pattern.

The invention provides a halftone phase shift photomask that is of much more simplified structure and so can be fabricated much more easily, which comprises a transparent substrate 10 and a single halftone light-blocking and phase shift layer 11 that is formed on the surface thereof according to a predetermined pattern and is made up of a material of homogeneous composition, characterized in that: said single halftone light-blocking and phase shift layer has a film thickness d that is virtually equal to a value defined by

Halftone phase shift photomask comprising a single layer of halftone

An overlying shifter type phase shift photomask used to produce semiconductor integrated circuits of high integration density, e.g. VLSI, ULSI, etc., which is capable of transferring fine-line patterns to a wafer by projection exposure. The photomask is produced by forming at least a light-blocking layer pattern or a combination of a light-blocking layer pattern and an etching stopper layer for a shifter layer on a transparent substrate, forming a shifter layer over the whole surface of the substrate, and then patterning the shifter layer to form a shifter layer pattern. The production method includes the step of polishing away unevenness on the surface of the shifter layer caused by a step which is produced by the light-blocking layer pattern, thereby leveling the surface of the shifter layer.

Overlying shifter type phase shift photomask blank, overlying shifter

The invention provides a phase shift photomask which includes an etching stopper layer transparent to ultraviolet illumination light and well resistant to etching as well as chemicals, acids, etc., and enables a phase shift angle to be controlled with high accuracy. In a phase shift photomask including a transparent substrate 210, and an etching stopper layer 202 and at least a phase shifter pattern 204 stacked on the substrate in this order, the etching stopper layer 202 is composed predominantly of hafnium oxide.

Blanks for phase shift photomasks, and phase shift photomasks

A halftone phase shift photomask designed so that it is possible to shorten the photoengraving process, use a production line for a conventional photomask, prevent lowering of the contract between the transparent and semitransparent regions at a long wavelength in the visible region, which is used for inspection and measurement, and also prevent charge-up during electron beam exposure, and that ordinary physical cleaning process can be used for the halftone phase shift photomask. The halftone phase shift photomask has on a transparent substrate (1) a region which is semitransparent to exposure light and a region which is transparent to the exposure light so that the phase difference between light passing through the transparent region and light passing through the semitransparent region is substantially .pi. radians. A semitransparent film that constitutes the semitransparent region is arranged in the form of a multilayer film including layers (3, 4) of chromium or a chromium compound. For example, the layer (3) is formed of chromium oxide, chromium oxide nitride, chromium oxide carbide, or chromium oxide nitride carbide, and the layer (4) is formed of chromium or chromium nitride. The layer (3) mainly serves as a phase shift layer, while the layer (4) mainly serves as a transmittance control layer that suppresses the rise of transmittance at the long wavelength side. The semitransparent film is formed by physical vapor deposition.

The invention is directed to a phase shift photomask for which a film made of a material capable of providing an etching stopper layer that excels in etching selectivity and can interrupt etching surely and automatically, and provides a phase shift photomask at least comprising a substrate 30 and a phase shifter pattern made of a material composed mainly of silicon oxide that is provided on the surface of the substrate directly or with an opaque layer 37 interposed therebetween, said phase shift photomask being characterized in that the surface 30 is provided on the surface with an etching stopper layer 30 that comprises a mixture of Al.sub.2 O.sub.3 with MgO, ZrO.sub.2, Ta.sub.2 O.sub.5 or HfO, or CrO.sub.x, CrN.sub.y, CrC.sub.z, CrO.sub.x N.sub.y, CrO.sub.x C.sub.z or CrO.sub.x N.sub.y C.sub.z, or MgF.sub.2-2x O.sub.y, CaF.sub.2-2x O.sub.y, LiF.sub.2-2x O.sub.y, BaF.sub.2-2x O.sub.y, La.sub.2 F.sub.6-2x O.sub.y or Ce.sub.2 F.sub.6-2x O.sub.y, whereby the etching stopper layer is allowed to etch a transparent film for a phase shifter surely and accurately, when making a phase shifter pattern by etching.

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Tokyo, Japan

Hiroyuki Miyashita