JP2002278045A - Method for touching up metal image on mask for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touching-up method as a method for imparting new images to a faulty pattern part of a metal image on a mask for exposure and to an image unformed part. SOLUTION: In the method for touching up a mask for exposure with a metal image formed on a transparent supporting substrate without substantially incorporating an organic binder, a silver-containing agent solution and a reducing agent solution are supplied to the top of the substrate or to a defective part of the metal image to form a metal film. Preferably a sulfite is contained in at least one of the silver-containing agent solution and the reducing agent solution, a silver ion complex forming agent other than the sulfite is further contained and a metal oxide is contained in the silver-containing agent solution. Preferably at least one step for previously producing a metal oxide layer and a metal or metal sulfide layer on the substrate is carried out before the formation of a metal silver film. Further preferably at least one treating step using a pH buffer solution is carried out after the formation of the metal silver film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of rewriting a metal image provided on an exposure mask for forming a circuit pattern or the like.

[0002]

2. Description of the Prior Art According to Isao Tanabe, Yoichi Takebana, and Moruhisa Homoto, "Story of Photomask Technology," Industrial Research Committee (1996), an exposure mask is a silver halide photographic emulsion layer on a transparent substrate such as a film or glass. (Emulsion mask) and a thin metal film (hard mask) such as chromium. With the recent trend toward smaller and finer printed circuit boards, exposure masks are required to have higher dimensional accuracy than ever before, and the market for base materials is gradually shifting from film to glass.

When the silver halide photographic photosensitive layer is irradiated with light, the emulsion mask forms a blackened image by developing silver halide in a photosensitive portion. Emulsion masks using silver salt photography are easy to achieve high sensitivity corresponding to a laser light source and the system is simple.
Since the blackened silver is dispersed in a relatively thick film of μm to 6 μm, the image quality is degraded by the thickness of the image, no matter how hard the photographic processing is performed, so that it is not suitable for an image of 10 μm or less.

On the other hand, the light-shielding film of the hard mask is a metal thin film, and the mainstream is a chromium film having a thickness of about 0.1 μm. Therefore, the reproducibility of a fine image of about 1 μm is excellent, but the steps such as the etching process are complicated, and the exposure mask cannot be easily obtained with a hard mask. In addition, the sharpness and stability of the resist film formation and drawing process using a high-sensitivity photopolymer are still insufficient, and are not suitable for directly drawing a fine image with a laser light source or the like. Moreover, chromium has environmental problems, and in recent years it has been required to switch to another method.

[0005] We have already disclosed in JP-A-2000-10258.
In Japanese Patent Laid-Open Publication No. H11-209, it has been proposed to obtain a light-shielding film for forming a circuit pattern for directly forming a silver image on a transparent substrate. According to this, the exposure mask material forms a silver film on a glass substrate by the principle of a silver complex salt diffusion transfer method (hereinafter, referred to as a DTR method). What is the DTR method?
Issue, or Focal Press, London New York (1972), by Andre Lott and Edith Weide Photographic Silver Silver
Unexposed silver halide dissolves and is converted to a soluble silver complex forming compound, which diffuses through the silver halide emulsion layer, as described in `` Halide Diffusion Processes '', and forms a physical development nucleus. It is developed at the location where it is formed to form a silver film. On the other hand, the silver halide in the exposed portion has a latent image nucleus formed by light irradiation, and is chemically developed in the emulsion layer.
If this is washed with warm water after development, the silver halide photographic photosensitive layer containing water-soluble gelatin as the main binder is removed, leaving only the silver film formed on the physical development nuclei in the unexposed areas on the glass substrate. To form an image. Since the obtained exposure mask does not contain gelatin, it is not discolored or denatured by heat or ultraviolet light even when used continuously as an exposure mask unlike an emulsion mask, and has a thickness of 1 μm or less on a glass substrate. Can be formed, and a metal silver image having a maximum optical density of 1.0 or more can be obtained, so that a fine image can be sharply reproduced.

However, a defective portion such as a pattern defect may occur in the obtained metal image. In a conventional correction technique, a method of selectively dissolving and removing the unnecessary portion by a photoetching method or an evaporation and removal by laser beam irradiation is known for erasing an unnecessary portion. In recent years, a repair device using a laser beam is often used for fine patterns.

On the other hand, as a technique for retouching a defective portion, a method of coating a resin containing a dye or pigment which absorbs light in a photosensitive wavelength range of a photosensitive resin to be patterned using the exposure mask is used. Or a method of coating with a silver paste or the like, or a method of coating a metal film by a vapor deposition method or a sputtering method. In the resin coating method, the resin is dissolved when the surface is washed with an organic solvent. Also, the silver paste as it is has low hardness and poor wear resistance. Heat treatment at several hundred degrees Celsius is required for curing, and there is a concern that the base material may be deformed, or image quality may be deteriorated at a non-touched portion.
In addition, the apparatus is expensive in the vapor deposition method and the sputtering method,
It is not easy to increase the size.

As described above, in the prior art, there is no simple method for adding a new image to a pattern-deficient portion or a non-image-formed portion of a metal image on an exposure mask. Was sought.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a retouching method for providing a new image to a pattern defect portion of a metal image on an exposure mask and a portion where an image is not formed.

[0010]

As a result of investigations by the present inventors, in an exposure mask in which a metal image is formed on a transparent supporting substrate without substantially including an organic binder, the mask is exposed on the substrate or the metal image. The above problem was solved by supplying a silver-containing agent solution and a reducing agent solution to the defective portion to form a metallic silver film. Preferably, at least one of the silver-containing agent solution or the reducing agent solution contains a sulfite,
More preferably, at least one of the silver-containing agent solution or the reducing agent solution contains a silver ion complexing agent other than the sulfite, and even more preferably, the silver-containing agent solution contains a metal oxide. The above problem has been solved.
Preferably, in the step before forming the metallic silver image, by having at least one step of preparing a metal oxide layer on the substrate in advance, more preferably, in the step before forming the metallic silver image, The above object has been attained by providing at least one step of forming a metal or metal sulfide layer on a substrate. More preferably, the above problem has been solved by providing at least one step of processing with a buffer solution in the step after forming the metallic silver image.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, the portion where rewriting of the metal image on the exposure mask is required is a portion where the metal film constituting the image is present in the image portion, but the optical density is low and the portion which becomes practically problematic as the exposure mask, It refers to an image-deficient portion such as a partially missing or broken wire, or a minute point defect (pinhole), or a portion that originally has no metal image and needs to be newly provided with an image.

The retouching method of the present invention comprises a) a reduction step, and b) a water washing step. Further, c) a metal oxide layer forming step, d) a metal or metal sulfide layer forming step,
e) It is also possible to add one or more of the stopping steps.

As the transparent support substrate in the present invention, a glass substrate, a plastic substrate or the like can be used. As the glass substrate, a glass substrate known to those skilled in the art can be used. Although it is necessary to select according to the use, required performance, and the like, examples include soda lime glass such as soda lime and white crown, low expansion glass such as borosilicate, alkali-free, and aluminosilicate, and synthetic quartz glass.

Examples of the plastic substrate include polyesters, polyamides, polyimides, polycarbonate, polystyrene, polyethylene terephthalate, polyolefins (polyethylene, polypropylene, etc.), polyvinyl halides (polyvinyl chloride, etc.), cellulose derivatives, etc. Can be used.

Various silver salts can be used in the silver-containing agent solution used in the reduction step of the present invention. In a preferred embodiment of the present invention, silver nitrate is used. 5 g or more, preferably 10 g to 200 g per 1 L of the silver-containing agent solution is good.

The silver-containing agent solution of the present invention may contain an acidic substance (for example, sulfuric acid or phosphoric acid), a thickener (for example, carboxymethyl cellulose), etc. in addition to the above-mentioned components.

Many reducing compounds can be used in the reducing agent solution used in the reduction step of the present invention. For example, polyhydroxybenzenes, 3-pyrazolidinones, ascorbate and the like or polysaccharides used as a photographic developing agent can be used. They are,
The optimum one can be selected depending on the composition and concentration of the silver-containing agent solution.

The reducing agent solution of the present invention may contain an alkaline substance (for example, potassium hydroxide or sodium hydroxide), a thickener (for example, carboxymethyl cellulose), etc., in addition to the above-mentioned components.

In the present invention, the pH of the reducing agent solution can take various values, but is usually 10 to 14, preferably 11 to 14.
4 is good.

The reduction step of the present invention can be divided into a plurality of steps. At that time, the requirements for the above-described reduction step and the reducing agent solution may be satisfied in at least one of the respective reduction processing steps.

In the present invention, examples of the sulfite include sodium sulfite and potassium sulfite. Sulfites function as a silver ion complexing agent in a silver-containing agent solution, and as a silver ion complexing agent and a preservative for a reducing agent in a reducing agent solution. The addition amount is 10 g or more per liter of the silver-containing agent solution or the reducing agent solution, preferably 2 g.
0 g to 200 g is good.

In the present invention, examples of the silver ion complexing agent other than the sulfite include various agents known to be capable of dissolving a silver salt and forming a complex. Include thiosulfates, amines, thioethers, thiocyanates and the like.
Examples of the thiosulfate include sodium thiosulfate, potassium thiosulfate, and ammonium thiosulfate. The amount of the thiosulfate to be added to the silver-containing agent solution and the reducing agent solution can take various values depending on the types (composition and concentration) of the silver-containing agent solution and the reducing agent solution, the combination with other components, and the like. 0.1 g or more per liter of solution, preferably
0.5g-50g is good. Amines are ammonia,
Substituted or unsubstituted by a saturated or unsaturated alkyl group, cycloalkyl group, alkoxy group, aryl group, alkanoyl group, aroyl group, heterocyclic group, and these substituents are bonded to each other to form a ring. May be formed. Specific examples are shown below.

[0023]

Embedded image

The amount of amines added to the silver-containing agent solution and the reducing agent solution can take various values depending on the type (composition and concentration) of the silver-containing agent solution and the reducing agent solution, the combination with other components, and the like. . 1 g to 50 g per 1 L of the solution is preferred. In the present invention, the silver ion complex forming solvent other than the sulfite contained in the silver-containing agent solution and the reducing agent solution may be used alone or in combination.

The metal oxide of 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 substance of amorphous silicic anhydride. In addition to unmodified, the surface of 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. Further, saponite, hectorite, and smectite group such as montmorillonite, vermiculite group, kaolinite-serpentine group such as kaolinite and halosite, natural clay minerals such as sepiolite, such as fluorophlogopite, tetrasilicic mica, and teniolite Synthetic inorganic polymers such as fluoromica and synthetic smectite can also be used.

The layer composed of these metal oxides or hydroxides can be prepared by any method known to those skilled in the art, but is most easily finely dispersed in a solvent and formed on a transparent substrate. Is applied and held. In this case, the particle diameter of the finely dispersed metal oxide or hydroxide is about 1 nm to 100 μm.

The metal or metal sulfide used in the present invention may be a known metal similar to a physical development nucleus usually used in a silver complex salt diffusion transfer method. For example, metal colloids such as gold and silver or silver, palladium and the like can be used. A metal sulfide obtained by mixing a water-soluble salt such as zinc and a sulfide can be used. Various hydrophilic colloids can be used as the protective colloid.
For details and manufacturing method thereof, see, for example,
-30562, JP-A-48-55402 and 53-
21602, Focal Press, New York, London (1972). See "Photographic Silver Halide Diffusion Processes" by Andre Lott and Edith Weide. Further, a surfactant can be contained as a coating aid.

The terminating step referred to in the present invention is a step of neutralizing the solution in the reducing step to stop the reaction. The pH of the stop solution is preferably 5 or more, more preferably 5.5.
It is preferably at least 8 and at most 8. The stop solution preferably contains a pH buffer component. As the pH buffer component, various components known to those skilled in the art can be used, and specific examples include a combination of potassium hydrogen phthalate + hydrochloric acid, potassium hydrogen phthalate + sodium hydroxide, and the like.

The stop solution may contain phosphoric acid and phosphate. For example, phosphoric acid, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, monopotassium dihydrogen phosphate, or the like can be used.

The rinsing step in the present invention is intended to wash away substances remaining on the surface in the preceding processing steps and to prevent the residual substances from deteriorating the image due to aging or oxidation by air. I do. Preferably, it is good to wash with pure water.

In the retouching method of the present invention, various members capable of supplying a liquid can be used. For example, a syringe, a brush, etc. are applicable.

The thickness of the metallic silver image of the present invention is 1 μm or less, and the maximum optical density of the metallic silver image is 1.0 or more.
The surface of the glass substrate is not always flat, and the thickness of the metallic silver film is not always constant due to the influence of the deviation in the coating process or the particulate matter contained in the mask material for exposure. Therefore, the thickness of the metallic silver image in the present invention is indicated as an average thickness in a size of 10 mm × 10 mm square or more. The optical density of the metallic silver image varies depending on the type of the image. For example, in a very fine image, the optical density can be reduced to half or less than that in a large area (so-called solid part). Similarly, in the present invention, the maximum optical density refers to the maximum density at the central portion of a metallic silver image of 10 mm × 10 mm square or more.

[0033]

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 Exposure masks have already been disclosed in JP-A-2000-1025.
No. 8 was prepared by the means proposed in the publication.

The silver-containing agent solutions were prepared according to the compositions shown in Table 1 below to obtain silver-containing agent solutions 1 to 4. In Table 1, as the titania sol, titania sol TA-15 manufactured by Nissan Chemical Industries, Ltd. was mixed.

The reducing agent solution was prepared as shown below. Sodium sulfite 100g Sodium hydroxide 25g Hydroquinone 15g Total (adjusted with pure water) 1kg

The stop solution was prepared by adding 29 mL of a 0.1 mol / L sodium hydroxide solution to 50 mL of a 0.1 mol / L monopotassium dihydrogen phosphate solution, diluting the solution to 100 mL with pure water, and adjusting the pH to 7.0. Prepared.

The silver-containing agent solution 1 was applied to the image defect portion of the exposure mask.
3 to 4 μL were dropped in a syringe and air-dried. Thereafter, 3 μL of a reducing agent solution was added dropwise to precipitate metallic silver.
Here, the reducing agent solution can be supplied without drying the silver-containing agent solution naturally. Subsequently, pure water was dropped and sucked with a wiper to obtain samples A to D.

A 0.3 μL-thick titania sol TA-15 manufactured by Nissan Chemical Industries, Ltd. was applied to the image defect portion of the exposure mask.
And dried at room temperature to form a metal oxide layer. Thereafter, samples E and F were obtained through the same steps as for samples C and D.

A palladium sulfide solution was prepared in an aqueous solution of polyethylene glycol / alkyl ether, and applied to a substrate so that the amount of palladium sulfide was 1.0 mg / m ² .
Dry to form a metal sulfide layer. Thereafter, through the same steps as for sample D, sample G was obtained.

After a reduction step was performed in the same manner as in Sample G, 10 μL of a stop solution was dropped to stop the reaction, and the solution on the exposure mask was sucked off with a wiper. Finally, pure water was dropped and sucked with a wiper to obtain a sample H.

Evaluation of the retouched portion was performed based on the optical density, adhesive strength and stability over time of the obtained metallic silver thin film. The optical density was measured with an optical densitometer (Macbeth TR924) and evaluated according to the following criteria. X: Very low. Not practical. Δ: Low, but practically acceptable. ：: High optical density. A: Very high optical density. The results obtained are summarized in Table 2.

The adhesive strength was evaluated by visually observing the degree of formation of scratches and the like due to wiping, and evaluated according to the following criteria. X: Very low. Not practical. Δ: Low, but practically acceptable. ：: Adhesive strength is high. A: Very high adhesive strength. The results obtained are summarized in Table 2.

The stability over time was evaluated based on the following criteria by observing the change in the surface gloss of metallic silver. ：: The gloss is reduced, but practically acceptable. A: Gloss does not change. The results obtained are summarized in Table 2.

[0045]

[Table 1]

[0046]

[Table 2]

As shown in the results of Sample A, the metal silver film obtained from the reduction step using the silver-containing agent solution and the reducing agent solution makes it possible to rewrite the pattern defect portion of the metal image on the exposure mask. It could be confirmed. In addition, a comparison between Sample A and Sample B confirmed that the addition of a sulfite in the silver-containing agent solution enables writing with a higher optical density.
From Sample C, it was confirmed that a metal film having high adhesive strength was formed by further containing a silver ion complexing agent. sample
From D, E, and F, it was confirmed that higher adhesive strength can be realized by incorporating the metal oxide in the silver-containing agent solution, forming a layer in advance, or performing both. From Sample G, it was confirmed that a metal silver film having a higher optical density can be formed by forming a metal sulfide layer in advance. From sample H,
It was confirmed that by performing the stop step after the reduction step, a metallic silver film having no change in surface gloss with time could be obtained.

[0048]

As described above, according to the present invention,
It was possible to provide a retouching method for providing a new image to a pattern defect portion of a metal image on an exposure mask and a non-image-formed portion.

Claims (7)

[Claims] 1. An exposure mask in which a metal image is formed on a transparent support substrate without substantially containing an organic binder,
A metal image retouching method comprising supplying a silver-containing agent solution and a reducing agent solution on the base material or on a defective portion of the metal image to form a metal silver film. 2. The method according to claim 1, wherein at least one of the silver-containing agent solution and the reducing agent solution contains a sulfite. 3. The method for retouching a metal image according to claim 1, wherein at least one of the silver-containing agent solution and the reducing agent solution contains a silver ion complex-forming agent other than a sulfite. 4. The method according to claim 3, wherein the silver-containing agent solution contains at least one kind of metal oxide. 5. The method according to claim 3, further comprising, before forming the metallic silver image, at least one step of preparing a metal oxide layer on the base material in advance.
How to add the metal image described. 6. The method according to claim 3, further comprising at least one step of previously forming a metal or metal sulfide layer on the substrate before the step of forming the metallic silver image. How to add the metal image described. 7. A process for forming a metallic silver image, comprising the steps of:
7. The metal image retouching method according to claim 1, wherein there is at least one step of processing using a buffer solution.