JP2009108352A - Etching solution for mask for display, and method for manufacturing mask for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etching solution which can provide such a large, highly precise mask for a display as to reproduce a pattern in a design drawing with high precision, and has superior etchability and etching accuracy, and to provide a method for manufacturing the mask for the display. <P>SOLUTION: The etching solution for the mask for the display comprises: an etching agent containing at least ceric ammonium nitrate, and a surface active agent in water. The surface active agent is a mixture of a perfluoroalkyl sulfonate having a fluorocarbon group of a straight chain in an amount of 70 to 80 mass% and a perfluoroalkyl sulfonate having a fluorocarbon group of a branched chain in an amount of 20 to 30 mass%. The method for manufacturing the mask for the display includes etching a substrate of the mask for the display by using the etching solution. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mask etching solution for a display, and in particular, for a large-sized high-precision display used for manufacturing a color filter, a wiring or an electrode, a plasma display panel, an electroluminescence panel, etc. used in a liquid crystal display device. A mask for a display having excellent etching characteristics and etching accuracy (hereinafter, these characteristics may be collectively referred to as “etching characteristics”) capable of obtaining a mask (hereinafter also referred to as “display mask”). The present invention relates to an etching solution (hereinafter sometimes simply referred to as “etching solution”) and a method for manufacturing a display mask.

  In recent years, display panels such as color filters and plasma display panels of the above-mentioned liquid crystal display devices have been manufactured in accordance with the increase in size and high-definition such as 40 inches and 50 inches, and their associated wiring or electrodes. In this case, the display mask used for exposing and drawing the pattern of the design drawing in the manufacturing process is enlarged to the current size, and high precision corresponding to the high number of pixels is required.

  The above-mentioned display mask needs to suppress the influence of light reflection between the mask and the substrate as much as possible in order to accurately draw and draw the design drawing and the like. Also, since it is necessary to further increase the light shielding power, the conventional chromium metal It is composed of a single metal thin film or a composite metal thin film composed of a plurality of metal thin films.

  In general, an etching solution used for manufacturing a display mask is used as in the following manufacturing example. For example, after forming a metal thin film on a large transparent glass substrate such as low expansion glass or synthetic quartz by a method such as vapor deposition or sputtering, the photosensitive resin composition is spin coated, slit coated, roll After the metal thin film is uniformly coated by a known method such as a coating method or a spray method, a desired pattern is exposed and drawn with an active energy ray, and then developed with a developer such as an organic solvent or an alkaline aqueous solution. After development, after performing a baking process to improve the etching resistance of the resist film as necessary, after etching a metal thin film not covered with an etching mask with an acidic etchant by a method such as spraying or dipping Then, the display mask is obtained by removing the resist film.

  The above etching solution is required to have an etching characteristic that can provide a large and highly accurate display mask. That is, there is a demand for etching characteristics that provide wettability that allows uniform etching across the entire mask without variation and that provides a highly accurate display mask that is reproduced according to the design drawing.

  However, when a large display mask is manufactured using a conventional etchant, the entire mask surface for the display is uniform and the etching accuracy that can be uniformly etched is inferior. A high-precision display mask cannot be obtained.

  The acidic etching solution is used alone or with the addition of a surfactant for the purpose of improving wettability. However, conventional etchants containing a hydrocarbon-based surfactant have chemical stability such as oxidation resistance against the strong oxidizing etchant, and etching base materials and resists. Since sufficient performance such as wettability with respect to the surface cannot be exhibited, satisfactory etching characteristics cannot be obtained, and a high-precision display mask cannot be obtained.

  An etching composition (Patent Document 1) using a certain fluorine-based surfactant instead of the above-described hydrocarbon-based surfactant has been proposed. However, since the surfactant disclosed in Patent Document 1 is not sufficiently soluble or compatible with the etching solution, it has an adverse effect on sufficient wettability and etching speed with respect to the mask substrate for display and resist pattern. In addition, after etching, sufficient etching characteristics cannot be obtained, for example, a shape defect is generated in the obtained display mask.

  In view of the above, there has been a demand for an etching solution with excellent etching characteristics and a method for manufacturing a display mask that can provide a highly accurate display mask.

Japanese Patent Publication No. 63-45461

  Accordingly, an object of the present invention is to provide an etching solution with excellent etching characteristics and a method for manufacturing a display mask, which can obtain a large-scale high-precision display mask accurately reproduced according to a design drawing.

  As a result of diligent studies to solve the above-mentioned problems, the present inventors have found that an etching solution containing the following etching agent and a specific surfactant in water can be used to obtain a large high-precision display mask. It has been found that the etching solution has excellent characteristics. That is, the present invention is a perfluoroalkyl sulfonic acid comprising an etching agent containing at least ceric ammonium nitrate and a surfactant in water, wherein the surfactant has a linear fluorocarbon group. Etching characterized in that it is a mixture of 70 to 80% by mass of salt and 20 to 30% by mass of perfluoroalkyl sulfonate having a branched fluorocarbon group (hereinafter sometimes referred to simply as [E component]). Provide liquid.

  Moreover, in preferable embodiment of this invention, carbon number of the said linear and branched fluorocarbon group is 4, 6, 8, and carbon number (x) of the said linear fluorocarbon group And the carbon number (y) of the branched fluorocarbon group is x = y, the base of the perfluoroalkyl sulfonate is sodium, potassium, lithium, or ammonium, and the concentration of the mixture is 0.001 to 0.1% by mass, further containing perchloric acid or perchloric acid and nitric acid, and the concentration of the etching agent is 15 to 40% by mass, and the etching agent Is a mixture of ceric ammonium nitrate (p) and perchloric acid (q) or perchloric acid and nitric acid (r), and the blending ratio is q / p = 25 to 75/100 (mass ratio) ), R / p = 30-80 / 100 ( A ratio), and mixing ratio of the perchlorate (r1) and nitric acid (r2) is to provide an etching solution which is r2 / r1 = 20~80 / 100 (mass ratio).

  According to a preferred embodiment of the present invention, there is provided a method for manufacturing a display mask, wherein the display mask substrate is etched using the etching solution. In this manufacturing method, the mask substrate for display is made of a chromium / chromium oxide composite, a chromium / chromium nitride composite, a chromium oxide / chromium / chromium oxide composite, chromium / nickel (alloy) / A color filter, wiring, or electrode of a liquid crystal display device that is a composite of nickel oxide (alloy) or a composite of nickel (alloy) / chromium / chromium oxide, and the display mask is large and has a large number of pixels It is preferable to be used for plasma display, plasma display and electroluminescence panel.

  ADVANTAGE OF THE INVENTION According to this invention, the etching liquid excellent in the etching characteristic from which the large-sized display mask with the high precision as a design drawing is obtained, and the manufacturing method of a display mask are provided.

Next, the present invention will be described in more detail with reference to preferred embodiments. The perfluoroalkyl sulfonate which is the E component which mainly characterizes the present invention is a perfluoroalkyl sulfonate having a linear fluorocarbon group represented by the following general formula (1) of 70 to 80% by mass and a general formula It is a mixture with 20-30 mass% of perfluoroalkyl sulfonates having a branched fluorocarbon group represented by (2).
Rf ₁ SO ₃ M (1)
Rf ₂ SO ₃ M (2)
(Rf ₁ and Rf ₂ in the above formula are fluorocarbon groups in which all of H of the alkyl group having 4 to 8 carbon atoms is replaced with F, Rf ₁ is a linear fluorocarbon group, Rf ₂ is a branched fluorocarbon group, and M is an alkali metal or quaternary ammonium group.)

  By using each of the above-mentioned perfluoroalkyl sulfonates having a linear or branched fluorocarbon group in the above blending ratio, an etching solution exhibiting an effect excellent in etching characteristics can be obtained.

  The perfluoroalkyl sulfonate having a linear fluorocarbon group in the component E has a high surface activity, but is very difficult to dissolve in a solution containing a large amount of ionic substances such as an etching solution. On the other hand, a perfluoroalkyl sulfonate having a branched fluorocarbon group has good solubility, but its surface activity is inferior to that of a perfluoroalkyl sulfonate having a linear fluorocarbon group.

  By mixing the perfluoroalkyl sulfonate having an appropriate branched fluorinated carbon group into the perfluoroalkyl sulfonate having a linear fluorocarbon group, the solid E The crystallinity of the component can be lowered, the E component can be dissolved in a high concentration in the etching solution, and the surface tension can be sufficiently reduced.

  When the ratio of the perfluoroalkyl sulfonate having a linear fluorocarbon group in the E component exceeds the upper limit, the solubility in the etching solution is low, and the sulfonate is likely to precipitate due to temperature change. As a result, the surface tension becomes high. On the other hand, if the ratio of the perfluoroalkyl sulfonate is less than the lower limit, the surface tension also increases, and sufficient etching characteristics cannot be obtained.

  The perfluoroalkyl sulfonate having the above-mentioned linear and branched fluorocarbon groups has 4 to 8 carbon atoms in the fluorocarbon group constituting them, and preferably has 4, 6, or 8 carbon atoms. In particular, those having 8 carbon atoms are used. When the above carbon number exceeds the above upper limit, the solubility in the etching solution is deteriorated, and when it is less than the above lower limit, it is easily dissolved in the etching solution, but the performance as a surfactant is deteriorated. To do.

  In addition, the perfluoroalkyl sulfonate is preferably one in which the carbon number (x) of the linear fluorocarbon group and the carbon number (y) of the branched fluorocarbon group are x = y. Is done. Examples of the perfluoroalkyl sulfonate include perfluoroalkyl sulfonates having 8 carbon atoms in linear and branched fluorocarbon groups. Etching solution using E component consisting of perfluoroalkyl sulfonates with the same number of carbon atoms in the above-mentioned linear and branched fluorocarbon groups exhibits better etching characteristics and provides a high-precision display mask. It is done.

  In the perfluoroalkyl sulfonate, the base is an alkali metal or a quaternary ammonium group, preferably sodium, potassium, lithium or ammonium, more preferably potassium or sodium. Other metal salts are not preferred for use because of their poor solubility in etching solutions.

  The concentration of the E component is preferably 0.001% by mass to 0.1% by mass in the etching solution, and more preferably 0.01% by mass to 0.07% by mass. If the concentration of the above E component exceeds the upper limit mass%, it will remain dissolved in the etching solution. On the other hand, if the concentration is less than the lower limit mass percent, the surface tension of the etching solution will not decrease, and good wet wetting Since the effect of the property cannot be obtained, the etching characteristics of the obtained etching solution are deteriorated.

  The etchant constituting the etching solution of the present invention contains at least ceric ammonium nitrate as an essential component, and preferably further contains perchloric acid or perchloric acid and nitric acid. In order to obtain excellent etching characteristics as an etchant, the etchant concentration in the etchant is preferably 15% by mass to 40% by mass. When the above-mentioned etching agent concentration exceeds the upper limit concentration, the solubility of the etching agent is deteriorated. On the other hand, when the etching agent concentration is less than the above lower limit, there is a problem that the etching rate is lowered.

  A preferable blending ratio of ceric ammonium nitrate (p) constituting the above-mentioned etching agent and perchloric acid (q), or perchloric acid and nitric acid (r) is q / p = 25 to 75/100 ( Mass ratio), r / p = 30 to 80/100 (mass ratio). If the above-mentioned perchloric acid (q), or the ratio of perchloric acid and nitric acid (r) exceeds the above upper limit, there is a problem that the solubility of ceric ammonium nitrate in the etching solution decreases and precipitates, If it is less than the above lower limit, the etching solution becomes unstable over time.

  Moreover, the blending ratio of perchloric acid (r1) and nitric acid (r2) in perchloric acid and nitric acid (r), which are the etching agents, is r2 / r1 = 20 to 80/100 (mass ratio). It is preferable. Nitric acid used in combination with the above perchloric acid is effective in adjusting the etching speed of perchloric acid. If the ratio of nitric acid is too large, the etching speed of the resulting etchant becomes too slow. On the other hand, if the ratio of nitric acid is too small, the etching speed is increased, and a high-precision display mask is obtained within the above range. Suitable for

  In the etching solution of the present invention, the above-mentioned etching agent containing ceric ammonium nitrate and the E component are appropriately blended in water, preferably so that each of the above components is within the above numerical range. Prepare by mixing and dissolving uniformly. It should be noted that additives other than the above components have a risk of remaining as a residue on the obtained display mask after etching, and it is preferable not to add them because of the influence on the resolution of the display mask.

  As water used for preparation of said etching liquid, ion-exchange water, soft water, distilled water etc., Preferably ion-exchange water is mentioned. Those containing divalent metal ions such as hard water are not preferable because they easily react with the fluoroalkylsulfonate and may reduce the effect as a surfactant.

  The etching solution of the present invention can be used for manufacturing a high-precision display mask used for manufacturing color filters, wiring or electrodes, plasma display panels, electroluminescence panels, etc. used in liquid crystal display devices. it can. In particular, it is effective for manufacturing a large-sized display mask of full size.

  The display mask manufacturing method using the etching solution of the present invention includes, for example, the following first to sixth steps. In other words, washed soda lime glass, white crown, low expansion glass such as borosilicate glass and non-alkali glass, high softening point glass such as aluminosilicate glass, multiple surfaces such as chromium oxide on the transparent substrate surface such as quartz glass The display mask is a first step in which a metal thin film composite having a thickness of 100 to 150 nm, preferably 120 nm to 130 nm is formed by sputtering or vacuum deposition of the metal constituting the display mask to form a display mask substrate. On the substrate, a positive photosensitive resin composition such as naphthoquinonediazide type is applied by a known method so as to have a thickness of 0.6 μm to 1.2 μm (dry film thickness), and dried to form a photosensitive resin coating film. The second step, exposure drawing of the desired pattern on the photosensitive resin coating film with ultraviolet rays Third step, after exposure, a fourth step of forming an etching resist mask by developing with an alkaline developer, after development, a baking step for improving the etching resistance of the resist film as necessary Then, a fifth step of performing etching for 40 seconds to 60 seconds by a spray method or an immersion method using the etching solution of the present invention to etch away the metal thin film composite not covered with the resist mask, and after the etching, The resist mask is removed with an alkaline stripping solution or an organic solvent-based stripping solution and washed to obtain a display mask.

  The display mask substrate is preferably a chromium / chromium oxide composite, a chromium / chromium nitride composite, a chromium oxide / chromium / chromium oxide composite, or chromium / nickel (alloy) from the upper side of the transparent substrate. A metal thin film composite such as a composite of nickel / nickel oxide (alloy) or a composite of nickel (alloy) / chromium / chromium oxide is used. The above chromium oxide is effective in suppressing the influence of light reflection between the mask and the substrate as much as possible in order to accurately expose and draw a desired design drawing using the obtained display mask. In the composite, nickel (alloy) and nickel oxide (alloy) are alloys of each metal and at least one selected from vanadium, molybdenum, and tungsten.

  The transparent substrate may be any known substrate that can be used as a transparent display mask substrate having a thickness of about 10 mm having a known dimensional stability. For example, washed soda lime glass, white Low expansion glass such as crown, borosilicate glass and non-alkali glass, high softening point glass such as aluminosilicate glass, quartz glass, and the like, preferably quartz glass.

  The display mask obtained by the above production method is particularly preferably used for the production of color filters, wirings and electrodes, plasma displays and electroluminescent panels of liquid crystal display devices having a large number of pixels of 40 inches or more in size. .

  As an example of producing a color filter using the above-described display mask of the present invention, for example, a negative photosensitive coloring composition (coloring resist) by a known method on a glass substrate in which a light shielding layer is patterned on a glass for color filter. ) And dried by heating to obtain a coating film of 1 to 3 μm (dry thickness). In order to form a desired pixel on the obtained coating film, exposure drawing is performed by irradiating ultraviolet rays with an exposure gap of 150 μm, a high-pressure mercury lamp or an ultra-high pressure mercury lamp, etc. through the display mask of the present invention prepared according to the design drawing. To do. After exposure, the photocured coating film is developed by spraying or dipping using an alkali developer, and unexposed portions are dissolved and removed to obtain desired pixels. A desired color filter can be obtained by repeating the above-described process of obtaining pixels for the number of colors required for the color filter.

  Next, the present invention will be described more specifically with reference to etching liquids K1 to K5 of the present invention and etching liquids L1 to L4 of comparative examples. In the text, “part” or “%” is based on mass unless otherwise specified. In addition, this invention is not limited to the following Example.

[Examples 1 to 5] (Etching liquids K1 to K5)
Etching agents K1 to K5 of the present invention were prepared by blending each component as shown in Table 1 using an etching agent, E component, and ion-exchanged water, and stirring and mixing uniformly. In addition, said E component is as follows.
E component E1: Perfluoroalkyl sulfonate having a linear fluorocarbon group (C ₈ F ₁₇ SO ₃ K) and perfluoroalkyl sulfonate having a branched fluorocarbon group (C ₈ F ₁₇ Mixture with 20 parts of SO ₃ K) E2: Perfluoroalkyl sulfonic acid salt having 70 parts of linear fluorocarbon group (C ₈ F ₁₇ SO ₃ K) and perfluoroalkyl sulfonic acid having branched chain fluorocarbon group Mixture with 30 parts of salt (C ₈ F ₁₇ SO ₃ K) E3: 70 parts of perfluoroalkyl sulfonate (C ₈ F ₁₇ SO ₃ Na) having a linear fluorocarbon group and branched fluorocarbon group perfluoroalkyl sulfonate having a _{(C 8 F 17 SO 3 Na} ) 30 parts of a mixture of E4: perfluoroalkyl sulfonate having a fluorocarbon group of straight chain (C ₈ F ₁₇ SO ₃ N ) A mixture of a perfluoroalkyl sulfonate _{(C 8 F 17 SO 3 Na} ) 25 parts with 75 parts of a branched chain fluorocarbon group of E5: perfluoroalkyl sulfonate having a fluorocarbon group of straight (C ₈ F ₁₇ SO ₃ Li) perfluoroalkyl sulfonates having 75 parts of branched chain fluorocarbon group _{(C 8 F 17 SO 3 Li} ) mixture of 25 parts of

[Comparative Examples 1 to 4] (Etching liquids L1 to L4)
Etching agents, surfactant G, and ion-exchanged water were used to mix the components as shown in Table 2, and the mixture was stirred and mixed uniformly to prepare etching solutions L1 to L4 of comparative examples. In addition, said surfactant G is as follows.
・ Surfactant G
G1: 90 parts of a perfluoroalkyl sulfonate having a linear fluorocarbon group (C ₈ F ₁₇ SO ₃ K) and a perfluoroalkyl sulfonate having a branched fluorocarbon group (C ₈ F ₁₇ SO ₃ K) ) Mixture with 10 parts G2: Perfluoroalkyl sulfonate (C ₈ F ₁₇ SO ₃ K) having a linear fluorocarbon group alone

上記表中の数値は配合部数を表す。

The numerical value in the said table | surface represents the number of mixing parts.

上記表中の数値は配合部数を表す。

The numerical value in the said table | surface represents the number of mixing parts.

[Examples 6 to 10 and Comparative Examples 5 to 8] (Display Mask Production Example)
A mask substrate for a display is prepared by forming a composite of a metal thin film having a total thickness of 120 nm consisting of chromium (90 nm) / chromium oxide (30 nm) on the surface of a 254 mm square washed quartz glass by sputtering. Then, a naphthoquinone diazide type positive resist (AZ Electronic Materials, AZ-1500) is coated on the metal thin film surface of the substrate by a known method so as to have a thickness of 1 μm (dry film thickness). : 1.0 [mu] m, 1.5 [mu] m, 2.0 [mu] m, 2.5 [mu] m, and 3.0 [mu] m square hole patterns with a space pitch ratio of 1: 1 to 1: 1.9 and a plurality of line patterns of 1 [mu] m to 50 [mu] m The test pattern consisting of And AZ300MIF or NMD-3 [2.38% tetramethylammonium hydroxide aqueous solution] manufactured by Tokyo Ohka Kogyo Co., Ltd.) to form an etching resist mask. Next, the etching resist mask is etched for 50 seconds by spraying using the etching solution of the above-described embodiment or comparative example adjusted to 23 ° C., and the metal thin film composite not covered with the resist mask is used. The body was removed by etching, and then the resist mask was removed and washed with an alkaline stripping solution or an organic solvent to obtain a display mask.

  Regarding the display masks obtained by the above production examples, the resolution limit and in-plane variation of the hole pattern were evaluated by the following measurement methods with respect to the accuracy. The evaluation results are shown in Table 3.

(Hole pattern resolution limit)
From the hole pattern, holes that are not completely etched are counted, and the resolution limit value of the hole pattern is measured. The etching property of microfabrication is evaluated from the above measurement results.

(In-plane variation)
A 10 μm line width of the display mask obtained by the above production example was selected, and the line width was measured with a laser microscope (OLSI 100 manufactured by Olympus Corporation) to evaluate in-plane variation. The etching accuracy is evaluated from the above measurement results.

  From the above evaluation results, the etching solution of the present invention has excellent etching accuracy for microfabrication and etching accuracy that can uniformly and uniformly etch the surface, and a high-precision display mask according to the design drawing can be obtained. It has been demonstrated that On the other hand, in the etching solution of the comparative example, particularly in the hole pattern, a large amount of remaining residue was observed when the pitch was narrow (1: 1 and there were many metal thin films to be etched).

  Since the etching solution of the present invention has excellent etching characteristics, it is a large display mask used in the manufacture of color filters, wirings or electrodes for liquid crystal display devices with a large number of pixels, plasma displays, and electroluminescent panels. Can be used effectively as an etching solution.

Claims (12)

  70-80% by mass of a perfluoroalkyl sulfonate salt containing at least ceric ammonium nitrate and a surfactant in water, wherein the surfactant has a linear fluorocarbon group. And a mask etching solution for display, which is a mixture of 20 to 30% by mass of perfluoroalkyl sulfonate having a branched fluorocarbon group.   The etching solution according to claim 1, wherein the linear and branched fluorocarbon groups have 4, 6, and 8 carbon atoms.   3. The etching solution according to claim 1, wherein a carbon number (x) of the linear fluorocarbon group and a carbon number (y) of the branched fluorocarbon group are x = y.   The etching solution according to any one of claims 1 to 3, wherein the base of the perfluoroalkyl sulfonate is sodium, potassium, lithium, or ammonium.   The etching solution according to claim 1, wherein the concentration of the mixture is 0.001 to 0.1% by mass.   Furthermore, the etching liquid of Claim 1 containing perchloric acid or perchloric acid and nitric acid.   The etching solution according to claim 1 or 6, wherein the concentration of the etching agent is 15 to 40% by mass.   The etching agent is ceric ammonium nitrate (p) and perchloric acid (q) or a mixture of perchloric acid and nitric acid (r), and the blending ratio is q / p = 25 to 75/100. The etching solution according to claim 1, wherein (mass ratio) and r / p = 30 to 80/100 (mass ratio).   The etching solution according to claim 8, wherein a mixing ratio of perchloric acid (r1) and nitric acid (r2) is r2 / r1 = 20 to 80/100 (mass ratio).   A method for manufacturing a display mask, comprising etching the display mask substrate using the etching solution according to claim 1.   The mask substrate for display is composed of a chromium / chromium oxide composite, a chromium / chromium nitride composite, a chromium oxide / chromium / chromium oxide composite, chromium / nickel (alloy) / nickel oxide (alloy) from the upper side of the transparent substrate. The method for manufacturing a display mask according to claim 10, which is a composite or a composite of nickel (alloy) / chromium / chromium oxide.   The method for manufacturing a display mask according to claim 10 or 11, wherein the display mask is a color filter, wiring or electrode, plasma display, and electroluminescence panel of a liquid crystal display device having a large size and a large number of pixels. .