JP2000112115A - Exposure mask and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure mask and its producing method by which an exposure mask can be easily produced. SOLUTION: This exposure mask has a light-shielding film on a transparent substrate and is used to form a circuit pattern. In this mask, metallic silver originating from silver halides in an unexposed region acts as catalyst nuclei on the transparent substrate, and the light-shielding film consists of a metal film formed on the catalyst nuclei. The silver halides in the unexposed region are dissolved, metallic silver is produced by development, and after the metallic silver is adsorbed on the transparent substrate, the photosensitive layer is removed and then the metal film is formed by using the adsorbed metallic silver as the catalyst nuclei.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exposure mask for forming a circuit pattern and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventional exposure masks include Isao Tanabe and
According to Yoichi Takehana and Morihisa Homoto, "Story of Photomask Technology," Industrial Research Committee (1996), a photographic emulsion containing silver halide (emulsion mask) or a metal thin film such as chrome (emulsion mask) on a transparent substrate such as a film or glass. A hard mask) is used to form a light-shielding film. The emulsion mask irradiates a photosensitive layer containing silver halide such as silver iodide with light and develops the same to form a blackened image. Such emulsion masks use silver salt photography, which is a highly sensitive and simple method, but has the disadvantage of poor heat resistance and ultraviolet light resistance due to the use of gelatin as the binder in the photosensitive layer. There is.

On the other hand, in the hard mask, the light-shielding film is a metal thin film, so that it has excellent heat resistance and ultraviolet light resistance.
In order to obtain a high-density exposure mask directly using a laser light source, the demand for which has been rapidly increasing in recent years, the process of forming a resist film using a photopolymer is rate-determining. Has not been reached.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure mask capable of easily producing an exposure mask and a method of manufacturing the same.

[0005]

The present inventors have studied and found that, in an exposure mask for forming a circuit pattern formed by providing a light-shielding film on a transparent substrate, an unexposed portion originated from silver halide. The above problem has been solved by an exposure mask characterized in that the metallic silver used as a catalyst nucleus on the transparent substrate and the light-shielding film is a metal film formed on the catalyst nucleus. Further, a photosensitive layer containing a silver halide emulsion is formed on a transparent substrate, and the silver halide in the light-irradiated portion is developed in the photosensitive layer, and at the same time, the silver halide in the non-light-irradiated portion is dissolved. Forming a metallic silver, after the metallic silver is adsorbed on the transparent substrate, removing the photosensitive layer, and further using the adsorbed metallic silver as a catalyst nucleus to form a metal film, The above problem was solved by a manufacturing method.
Further, in an exposure mask for forming a circuit pattern, which is provided with a light-shielding film on a transparent substrate, a metal silver layer having a metal oxide layer on the transparent substrate and derived from unexposed portions of silver halide However, the above problem has been solved by an exposure mask, wherein the mask serves as a catalyst nucleus on the metal oxide layer, and the light-shielding film is a metal film formed on the catalyst nucleus. Also,
A light-shielding film provided on a transparent substrate, in an exposure mask for forming a circuit pattern, silver derived from silver halide in an unexposed portion is present on the transparent substrate as an organic silver compound, and the light-shielding film is The above problem has been solved by an exposure mask, which is a metal film formed on an organic silver compound.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The present invention is a method of converting a light pattern incident as an exposure mask into a light-shielding film pattern by using a method of a photographic photosensitive material using silver halide. First, a photosensitive layer is formed on a transparent substrate. Next, when the silver halide in the photosensitive layer is irradiated with light, a latent image nucleus is formed inside or on the surface of the silver halide. Silver derived from silver halide is formed around the nucleus and blackened. Since this silver is inside the photosensitive layer, the silver is removed from the transparent substrate while removing the photosensitive layer with hot water or the like.

On the other hand, since the silver halide in the unexposed portion does not have a latent image nucleus inside or on the surface, when the silver halide is dissolved at the time of development, silver ions diffuse in the photosensitive layer. When this operation is performed in a reducing atmosphere, the diffused silver ions do not remain in the photosensitive layer but are reduced even on the transparent substrate to form colloidal metallic silver. At this time, when the photosensitive layer is adsorbed on the transparent substrate, it remains on the transparent substrate even after the photosensitive layer is removed with hot water or the like. The adsorbed metallic silver can be used as a catalyst nucleus and further as a nucleus for depositing a metal film from metal ions in a reducing atmosphere.

[0008] The method of depositing a metal film from metal ions in a reducing atmosphere is called electroless plating and is a technique that has been already established with various metals such as silver, gold, copper, and nickel.
It is described in detail in "Electroless Plating", edited by Electroplating Research Group, Nikkan Kogyo Shimbun (1994). The generated metal film appears without light irradiation, and a circuit pattern for an exposure mask can be formed. As a reducing agent for obtaining a reducing atmosphere, sodium porphynate, dimethylamine borane,
Hydrazine, potassium tetrahydroborate, formalin and the like are used.

In general, a light-shielding film made of a metal film can be formed in an unexposed area by the above method. However, when a latent image nucleus is formed in advance in silver halide and an electron-accepting substance is used in combination around silver halide, It is also possible to form a light-shielding film of a reversal type with respect to exposure, in which a light-shielding film made of a metal film can be formed on a transparent substrate by oxidizing and erasing a latent image nucleus only in an exposed portion.

As the transparent substrate, soda lime glass such as soda lime and white crown, low expansion glass such as borosilicate, alkali-free, aluminosilicate, synthetic quartz glass, polyester film, etc. can be used. Considering the ultraviolet properties, a transparent substrate using an inorganic glass is appropriate.

As the silver halide used in the present invention, silver chloride, silver bromide, silver iodide and the like can be used. These are synthesized by reacting silver ions and halogen ions in gelatin, and silver halides having various crystal structures such as a plate-like or core-shell type can be used. It is generally said that the larger the diameter of silver halide, the higher the sensitivity and the smaller the diameter, the lower the sensitivity.
It is used in the range of 00 μm.

In addition, it is possible to control the surface state of silver halide grains by adding iridium or rhodium-containing compound during the reaction of silver ions or halogen ions. These added compounds are used in an amount of 10 ^-8 to 10 ^-3 mol, preferably about 10 ^-7 to 10 ^-6 mol, per 1 mol of silver. Further, a chemical sensitizer, a spectral sensitizing dye, an antistatic agent and the like can be added.

Although silver halide is synthesized by reaction in gelatin, ionic impurities in gelatin tend to affect the photographic characteristics of silver halide, and thus must be sufficiently removed. In addition, an emulsion stabilizer may be mixed during the synthesis in order to impart dispersion stability in a gelatin aqueous solution of silver halide. Preferred stabilizers include azaindenes,
Heterocyclic mercapto compounds and the like. In the present invention, a material containing these silver halide, gelatin, additive compound, dispersion stabilizer and the like is called a silver halide emulsion, and a layer formed on a transparent substrate is called a photosensitive layer. The photosensitive layer contains silver halide in an amount of about 10 to 90% of its weight, and is kept at about 0.5 to 20 μm, preferably about 2 to 15 μm.

To dissolve silver halide, a mesoionic compound represented by alkanolamine, thioether, triazolium thiolate, sulfite, amine,
-Mercaptobenzoic acid, cyclic imide compounds, alkyl sulfones and the like can be used. Also, two or more kinds of 4,6-dihydroxypyrimidine and other silver halide solvents can be used in combination. These are used in addition to the developing solution.

Examples of the developer include hydroquinone,
P of methylhydroquinone, chlorohydroquinone, etc.
-Dihydroxybenzenes, such as sodium, potassium or ammonium thiosulfate, sodium, potassium or ammonium thiocinnate. These are used in addition to the developer.

The metal oxide for holding the colloidal metallic silver in the present invention is, for example, a metal oxide such as colloidal silica, colloidal alumina, titanium oxide, zinc oxide, zirconium oxide or a hydroxide thereof. Colloidal silica is a colloidal material of amorphous silicic anhydride. In addition to the unmodified silica, the surface of the silica is modified with ions and compounds such as ammonia, calcium, and alumina to behave in response to ionicity and pH fluctuation of particles. Modified colloidal silica in which is changed is also included. Colloidal alumina is an amorphous or pseudo-boehmite (including boehmite in a broad sense) alumina hydrate in the form of a colloid having a dispersed shape such as a feather-like, fibrous, or plate-like shape.

Furthermore, natural clay minerals such as smectites such as saponite, hectorite and montmorillonite, vermiculites, kaolinite-serpentine such as kaolinite and halosite, sepiolite, etc. Fluorine mica such as teniolite and synthetic inorganic polymers such as synthetic smectite can also be used.

The metal oxide layer applied on the transparent substrate is
After drying, the metal oxide particles may be heated to 150 ° C. or higher in order to increase the bonding force between the particles. 600
When heated to a temperature of not less than ° C., metal oxide particle growth is caused, and a strong metal oxide film can be formed.

In order to further form a metal oxide layer, an organometallic compound can be used. Examples of the organometallic compound include tetraethoxysilane, vinyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ
-Mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, aluminum isopropoxide, Organic metal compounds such as aluminum acetate, indium acetyl acetate, zinc acetyl acetate, zinc stearate, tetraethyl orthotitanate, tetraisopropyl orthotitanate, tetrabutyl orthotitanate, and barium oxalate can be used.

In some cases, these organometallic compounds can be combined with metal chlorides such as dimethyldichlorosilane, diphenyldichlorosilane, dimethylphenylchlorosilane, aluminum chloride and titanium tetrachloride. These organometallic compounds improve the retention and adhesion between the transparent substrate and the colloidal metallic silver, and eventually improve the adhesion of the resulting metal film. The organometallic compound is applied on a transparent substrate and forms fine particles of a metal oxide by heating or hydrolysis, and is further heated to increase the bonding force between the fine particles, thereby firmly holding the metal film on the transparent substrate. .

When the transparent substrate is a substrate having a surface hydroxyl group such as a glass substrate, the organic metal compound is chemically bonded to the surface by a substitution reaction of an alkoxy group such as an organic silicon compound or an organic titanium compound. Is possible. In the case of an organosilicon compound, a functional group such as an amino group, a thiol group, or a glycidyl group can be introduced into the substrate surface to improve the retention of the catalyst nucleus. In the case of an organic titanium compound, the acid resistance and the alkali resistance of the surface of the transparent substrate can be improved, and the retention of the catalyst nucleus can be improved. These can be used alone or in combination.

After the silver halide in the unexposed areas is dissolved and silver ions are released, in addition to using colloidal metallic silver as a catalyst nucleus generated under a reducing atmosphere, the released silver ions are converted to an organic silver compound. It is also an aspect of the present invention to capture as a substrate and adsorb it on a transparent substrate. The adsorbed organic silver compound is used as it is or is subjected to a reduction treatment to act as a catalyst nucleus when a metal film is formed. As the compound that becomes an organic silver compound by reacting with silver, for example, a sulfur-containing compound such as bismothiol, thiophenol, and various proteins can be used.

As described above, the metal film serving as the light-shielding film can be obtained by immersing the transparent substrate having the catalyst nucleus in the electroless plating solution, so that an exposure mask can be manufactured.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto without departing from the spirit of the present invention.

Example 1 Preparation of Photosensitive Layer 70 parts by weight of silver chloride containing 30 μm of silver chloride and 30 parts by weight of photographic gelatin (manufactured by Nitta Gelatin) containing an extremely small amount of rhodium chloride and iridium chloride and having an average particle size of 0.2 μm A silver chloride emulsion consisting of 300 parts by weight of water was prepared, this emulsion was heated to 40 ° C., coated with a spinner, quenched and dried at 25 ° C. with cold air for 12 hours to form a photosensitive layer having a thickness of 1 μm after drying. did. The preparation, coating, and drying steps of the emulsion were all performed in a dark room.

Preparation of Developer Solution Carboxymethylcellulose 4.0 parts by weight Sodium hydroxide 22.5 parts by weight Anhydrous sodium sulfite 120.0 parts by weight Hydroquinone 20.0 parts by weight 1-phenyl-3-pyrazolinone 6.0 parts by weight Bromide Potassium 0.8 part by weight Anhydrous sodium thiosulfate 8.0 parts by weight Ethylenediaminetetraacetic acid tetrasodium salt 2.0 parts by weight A solution of 1000.0 parts by weight of distilled water was prepared and used as a developer.

Exposure and Development Four 10-W fluorescent lamps are arranged and partially shielded from light.
Light was irradiated from a distance of 30 cm for 30 seconds. Thereafter, the film was immersed in a developer at 25 ° C. for 30 seconds to perform development. Next, the photosensitive layer was removed with warm water at 35 ° C., and colloidal metallic silver was adsorbed on the transparent substrate.

Preparation of electroless nickel-phosphorus alloy plating solution Nickel sulfate 21.0 parts by weight Sodium phosphinate 25.0 parts by weight Lactic acid 27.0 parts by weight Propionic acid 2.2 parts by weight Distilled water 1000.0 parts by weight Was prepared and used as a plating solution.

The prepared transparent substrate having metallic silver was immersed in the plating solution heated to 70 ° C. for 40 minutes, and then subjected to a washing and drying process to prepare an exposure mask a. The transmittance at 350 nm of the metal film portion of the produced exposure mask is 0.01.
% Or less.

Example 2 To 2 parts by weight of tetrapropyl orthotitanate was added to 1000 parts by weight of dehydrated methyl ethyl ketone, and the mixture was coated on a glass substrate. After drying the glass substrate at 60 ° C. for 20 minutes, the glass substrate was heated at 250 ° C. for 30 hours to obtain a thickness of 0.1 mm.
A titanium oxide layer having a thickness of 03 μm was formed. A photosensitive layer was formed on this layer in the same manner as in Example 1, exposed and developed, and further the photosensitive layer was removed. Then, nickel electroless plating was performed with the same nickel plating solution as in Example 1 to obtain a light-sensitive layer. Mask b was prepared. The light transmittance at 350 nm of the metal film portion of the exposure mask b was 0.01% or less.

Example 3 To 2 parts by weight of tetrapropyl orthotitanate, 20.8 parts by weight of tetraethoxysilane, and 12.6 parts by weight of bismothiol were added to 1000 parts by weight of dehydrated methyl ethyl ketone, and the mixture was coated on a glass substrate. . This glass substrate was heated to 60 ° C. in dry air, and further heated at 100 ° C. for 1 hour. A photosensitive layer was formed on this glass substrate in the same manner as in Example 1, exposed and developed, and the photosensitive layer was removed. Then, nickel plating was performed to prepare an exposure mask c. The ultraviolet transmittance of the light-shielding film was 0.01% or less.

Example 4 In 1000 parts by weight of dehydrated methyl ethyl ketone, γ-
20 parts by weight of mercaptopropyltrimethoxysilane was added and applied on a glass substrate. This glass substrate was heated to 60 ° C. in dry air, and further heated at 100 ° C. for 1 hour. A photosensitive layer was formed on this glass substrate in the same manner as in Example 1, exposed and developed, and after removing the photosensitive layer, nickel plating was performed to prepare an exposure mask d. The ultraviolet transmittance of the light-shielding film was 0.01% or less.

[0033]

As described above, according to the present invention,
It was possible to easily obtain an exposure mask having a sufficient light-shielding property.

Claims (4)

[Claims] In an exposure mask for forming a circuit pattern, comprising a light-shielding film provided on a transparent substrate, metallic silver derived from silver halide in an unexposed portion becomes a catalyst nucleus on the transparent substrate. An exposure mask, wherein the light shielding film is a metal film formed on the catalyst core. 2. A photosensitive layer containing a silver halide emulsion is formed on a transparent substrate, and the silver halide in a light-irradiated portion is developed in the photosensitive layer, and at the same time, the silver halide in a non-light-irradiated portion is dissolved. Forming a metallic silver at the time of development, after the metallic silver is adsorbed on the transparent substrate, removing the photosensitive layer, and using the adsorbed metallic silver as a catalyst nucleus to form a metal film, Production method. 3. An exposure mask for forming a circuit pattern, comprising a light-shielding film provided on a transparent substrate, wherein the mask has a metal oxide layer on the transparent substrate and is derived from unexposed portions of silver halide. An exposing mask, wherein the metallic silver forms a catalyst nucleus on the metal oxide layer, and the light-shielding film is a metal film formed on the catalyst nucleus. 4. An exposure mask for forming a circuit pattern, wherein a light-shielding film is provided on a transparent substrate, wherein silver derived from unexposed portions of silver halide is present on the transparent substrate as an organic silver compound. An exposure mask, wherein the light-shielding film is a metal film formed on the organic silver compound.