EP0643331A2
Expired / Lapsed
EP
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Halftone phase shift photomask, halftone phase shift photomask blank, and method of producing the blank
Assignee: Dai Nippon Printing Co Ltd
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Filing: 1994-08-17
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Granted: —
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Expires: 2014-08-17
Abstract
Abstract 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.
Inventors
- 👤 Hiroyuki C/O Dai Nippon Printing Co. Miyashita
- 👤 Hiroshi C/O Dai Nippon Printing Co. Mohri
- 👤 Masahiro C/O Dai Nippon Printing Co. Takahashi
- 👤 Naoya C/O Dai Nippon Printing Co. Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 11:46
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/32
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
41 words
A halftone phase shift photomask having on a transparent substrate a halftone phase shift layer which includes at least one layer composed mainly of a chromium compound, wherein said chromium compound contains at least fluorine atoms in addition to chromium atoms.
Claim 2
Dependent Claim
39 words
A halftone phase shift photomask according to Claim 1, wherein said chromium compound contains atoms of at least one element selected from the group consisting of oxygen, carbon, sulfur, nitrogen, and hydrogen, in addition to chromium and fluorine atoms.
Claim 3
Dependent Claim
58 words
A halftone phase shift photomask according to Claim 1 or 2, wherein said layer composed mainly of said chromium compound contains impurity atoms other than chromium, fluorine, oxygen, carbon, sulfur, nitrogen and hydrogen atoms within the range in which the refractive index for exposure light that is obtained by ellipsometry will not be changed by 0.1 or more.
Claim 4
Dependent Claim
147 words
A halftone phase shift photomask according to any of Claims 1 to 3, wherein said halftone phase shift layer is formed on said transparent substrate so that the phase difference φ, which is obtained by the following equation, falls within the range of nπ±π/3 radians (n is an odd integer): where φ is the phase change of light perpendicularly passing through the photomask having a multilayer (m-2 layers) film formed on said transparent substrate, x k,k+1 is the phase change occurring at the interface between the k-th layer and the (k+1)th layer, u k and d k are the refractive index of a material constituting the k-th layer and the thickness of the k-th layer, respectively, and λ is the wavelength of exposure light, and where the layer of k=1 is assumed to be said transparent substrate, and the layer of k=m is assumed to be air.
Claim 5
Dependent Claim
55 words
A halftone phase shift photomask according to any of Claims 1 to 4, wherein the transmittance for exposure light of said halftone phase shift layer is in the range of from 1% to 50% when the transmittance at an opening of said halftone phase shift layer for the exposure light is assumed to be 100%.
Claim 6
Dependent Claim
58 words
A halftone phase shift photomask according to any of Claims 1 to 5, wherein said halftone phase shift layer includes at least a layer of a chromium compound containing fluorine, and a layer of a material selected from the group consisting of chromium, chromium oxide, chromium nitride, chromium oxide nitride, chromium oxide carbide, and chromium oxide carbide nitride.
Claim 7
Dependent Claim
33 words
A halftone phase shift photomask according to any of Claims 1 to 6, wherein said chromium compound contains at least 100 fluorine atoms per 100 chromium atoms as analyzed by X-ray photoelectron spectroscopy.
Claim 8
Dependent Claim
34 words
A halftone phase shift photomask according to any of Claims 1 to 7, wherein said chromium compound contains not more than 150 oxygen atoms per 100 chromium atoms as analyzed by X-ray photoelectron spectroscopy.
Claim 9
Dependent Claim
34 words
A halftone phase shift photomask according to any of Claims 1 to 8, wherein said chromium compound contains not more than 250 carbon atoms per 100 chromium atoms as analyzed by X-ray photoelectron spectroscopy.
Claim 10
Dependent Claim
62 words
A halftone phase shift photomask blank for a halftone phase shift photomask, in particular a photomask according to any of claims 1 to 9, said blank having on a transparent substrate a halftone phase shift layer which includes at least one layer composed mainly of a chromium compound, wherein said chromium compound contains at least fluorine atoms in addition to chromium atoms.
Claim 11
Dependent Claim
47 words
A halftone phase shift photomask blank according to Claim 10, wherein the transmittance for exposure light of said halftone phase shift layer is in the range of from 1% to 50% when the transmittance of said transparent substrate for the exposure light is assumed to be 100%.
Claim 12
Independent Claim
70 words
A method of producing a halftone phase shift photomask blank having on a transparent substrate a halftone phase shift layer which includes at least one layer composed mainly of a chromium compound, wherein chromium is evaporated or sputtered from metal chromium or a chromium compound in a plasma generated from a gas containing fluorine atoms, thereby forming on said transparent substrate a layer composed mainly of a chromium fluoride compound.
Claim 13
Dependent Claim
34 words
A halftone phase shift photomask blank producing method according to Claim 12, wherein the evaporation of chromium is effected by bombardment with electrons accelerated by an electron gun, or bombardment with an ionized gas.
Claim 14
Dependent Claim
48 words
A halftone phase shift photomask blank producing method according to Claim 12 or 13, wherein the plasma that is produced from a gas containing fluorine atoms is generated by ionizing a fluorine atom-containing gas while introducing it into a space between the chromium source and the transparent substrate.
Claim 15
Dependent Claim
47 words
A halftone phase shift photomask blank producing method according to Claim 12 or 13, wherein the plasma that is produced from a gas containing fluorine atoms is generated by introducing a previously ionized, fluorine atom-containing gas into a space between the chromium source and the transparent substrate.
Claim 16
Dependent Claim
55 words
A halftone phase shift photomask blank producing method according to Claim 12 or 13, wherein the plasma that is produced from a gas containing fluorine atoms is generated by introducing a previously ionized gas into a space between the chromium source and the transparent substrate while introducing a fluorine atom-containing gas into the same space.
Claim 17
Dependent Claim
63 words
A halftone phase shift photomask blank producing method according to Claim 12, wherein a previously ionized, fluorine atom-containing gas is directed at the chromium source through a space between the chromium source and the transparent substrate, thereby evaporating chromium and also generating a plasma containing fluorine atoms, and thus forming on said transparent substrate a layer composed mainly of a chromium fluoride compound.
References Cited (Backward Citations)
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