JPH0241134B2 - DODENSEISANKAMAKUNOPATAANKEISEIHO - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a method for forming a pattern of a conductive oxide film, and particularly to a method of forming a pattern of a conductive oxide film used as an electrode of a gas discharge display panel or an EL display panel.
This invention relates to a method of patterning with high precision.

(b) Technical background Tin oxide (SnO ₂ ) or relatively low resistance indium oxide (In ₂ O ₃ ) is generally used as a transparent electrode for optical devices such as gas discharge display panels, EL display panels, or liquid crystal display panels. , or 1-10% _SnO2
It is well known that conductive oxide films made of In ₂ O ₃ or the like doped with are widely used.

(c) Prior Art and Problems By the way, when forming electrode patterns for various display panels using a conductive oxide film such as the one described above, it has conventionally been applied on the surface of a glass substrate 1 as shown in FIG. A resist film 3 is applied onto the conductive oxide film 2, and the resist film 3 is patterned into a predetermined pattern. Next, as shown in FIG. 2, the substrate 1 on which three predetermined resist film patterns are formed is
A metal powder layer 4 is applied to the entire surface by brush coating or spray coating using a suspended solution of metal powder such as zinc (Zn), which reacts with acid to generate nascent hydrogen. Form. then the third
As shown in the figure, the metal powder layer 4 is immersed in, for example, a dilute hydrochloric acid solution, and a chemical reaction is performed to reduce the portion of the conductive oxide film 2a exposed from the pattern of the resist film 3, and subsequently, the reduced portion is 2a is removed by etching with a mixed solution of hydrochloric acid (HCl) and nitric acid (HNO ₃ ), etc., and the resist film 3 pattern is dissolved and removed with a solvent to obtain the desired conductivity as shown in FIG. An electrode pattern 2b made of an oxide film 2 is formed.

However, in the method for forming a pattern of the conductive oxide film 2 as described above, the means for forming the metal powder layer 4 on the portion of the conductive oxide film 2 exposed from the pattern of the resist film 3 is made of zinc (Zn) or the like. The method used is to apply a suspension of metal powder by brushing or spraying.
It is difficult to apply metal powder to the surface of the conductive oxide film 2 with a uniform thickness, and furthermore, it is very difficult to repeatedly reproduce the same thickness. In short, with conventional methods, it is not easy to form a metal powder layer of uniform thickness with good reproducibility. Therefore, when reducing the conductive oxide film through this metal powder layer, it is difficult to always reduce the entire film surface quantitatively uniformly, and therefore, the subsequent etching process is also limited to the reduced portion (the conductive oxide film). It was difficult to remove the oxide film uniformly, and as a result, it was difficult to pattern the conductive oxide film 2 with high precision. In addition, the effective layer formation yield of the suspension solution is poor, and most of it is discarded, resulting in uneconomical losses. Furthermore, the above-mentioned brush coating method has the disadvantage that it tends to damage the film surfaces of the conductive oxide film 2 and the resist film 3.

(d) Purpose of the Invention In order to solve the above-mentioned conventional drawbacks, the present invention improves the means for forming a metal powder layer on the conductive oxide film portion exposed from the resist film pattern, and makes the metal powder layer uniform. It is an object of the present invention to provide a novel method for forming a pattern of a conductive oxide film, which allows the conductive oxide film to be formed to a desired thickness with good reproducibility and to pattern the conductive oxide film with high accuracy.

(e) Structure of the Invention According to the present invention, the object is to provide a method for patterning a conductive oxide film formed on a substrate surface in accordance with a pattern of a resist film formed thereon. The substrate on which the resist film pattern is formed is placed with the resist film forming side facing upward on the liquid level of a container containing a liquid in which metal powder that reacts with acid and generates nascent hydrogen is stored. Then, the container is rocked a predetermined number of times to immerse the resist film forming surface of the substrate in the liquid in the container, and the metal powder in the liquid is transferred to the conductive oxide film exposed from the resist film pattern on the substrate. a step of coating the metal powder layer on the surface, a step of reacting the metal powder layer applied on the substrate with dilute acid to reduce the coated conductive oxide film portion of the metal powder layer, and etching away the reduced portion. This is achieved by providing a method for patterning a conductive oxide film, which is characterized by comprising the steps of:

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings.

FIGS. 5 to 9 are cross-sectional views of essential parts showing one embodiment of the method for forming a pattern of a conductive oxide film according to the present invention in the order of steps.

First, as shown in FIG. 5, for example, a glass substrate 2
A resist film 23 is applied on the conductive oxide film 22 applied to the surface of
3 into a predetermined pattern. Next, as shown in FIG. 6, a processing basket 25 is placed in which the glass substrate 21 on which the resist film 23 pattern is formed is accommodated with the resist film 23 facing upward.
For example, the above-mentioned process container 26 contains a suspension solution 27 in which about 100 mg of metal powder made of zinc (Zn) or the like with an average particle size of 0.2 μm is added and suspended in 2000 c.c. of water. Resist film 23 surface is suspended in solution 27
Place it at a height of, for example, 1 cm above the liquid level. The distance α from the surface of the suspension 27 to the surface of the resist film 23 on the glass substrate 21 is preferably adjusted within the range of 0 to 3 cm in order to make the thickness and uniformity of the metal powder layer 24 to be formed. Thereafter, as shown in FIG. 7, the processing container 26 is swung several times using a oscillating device (not shown) that oscillates it from side to side, so that the entire surface of the glass substrate on which the pattern of the resist film 23 is formed is covered with the suspension. The solution 27 is applied in a gentle manner, and the container and substrate are left in their original parallel state for a predetermined period of time. As a result, a metal powder layer 24 made of zinc (Zn) or the like having a predetermined uniform thickness is formed on the portion of the conductive oxide film 22 exposed from the resist film pattern. The thickness of the metal powder layer 24 can be adjusted by adjusting the concentration of the metal powder suspended in the suspension solution 27, and can range from 1 to 20 μm depending on the thickness of the conductive oxide film 22 and the required pattern accuracy. It is preferable if it is formed within this range. Further, the average particle size of the metal powder is preferably 1 μm or less.

Next, the glass substrate 21 on which the metal powder layer 24 is formed is immersed in a 1 to 10% diluted hydrochloric acid (HCl) solution, and the nascent hydrogen generated by the chemical reaction at this time causes As shown in the figure, the conductive oxide film portion 22a covered with the metal powder layer and exposed from the resist film 23 pattern on the glass substrate 21 is reduced. In this reduction treatment, since the metal powder layer is formed to have a uniform thickness, reduction is uniform in quantity. Subsequently, the reduced portion 22a is removed by etching, for example, with a mixed solution of hydrochloric acid (HCl), nitric acid (HNO ₃ ), and water (H ₂ O) in a predetermined ratio, and the pattern of the resist film 23 is removed. By dissolving and removing it with a solvent, a desired electrode pattern 22b made of the conductive oxide film 22 can be obtained as shown in FIG. This electrode pattern corresponds to the reduction portion 2
2a, the etching removal is uniform in quantity, resulting in a highly accurate pattern.

In the above example, zinc (Zn) powder and dilute hydrochloric acid (HCl) were used as the metal powder and acid used to generate hydrogen in the nascent stage and reduce the conductive oxide film 22. However, it is not limited to this example, and for example, in addition to metal powders such as cadmium (Cd), aluminum (Al), iron (Fe), and dilute hydrochloric acid (HCl), dilute nitric acid, dilute sulfuric acid, etc. can be applied. Of course.

(g) Effects of the Invention As is clear from the above explanation, according to the conductive oxide film pattern forming method according to the present invention, the conductive oxide film portion exposed from the resist film pattern is
The metal powder layer can be formed uniformly by applying the liquid in which the metal powder is suspended, so that the subsequent reduction and etching can be made uniform in quantity and the conductive oxide film can be patterned with high precision. It is. Moreover, since the metal powder is applied mechanically, it is possible to repeatedly form a pattern with high accuracy, that is, to form a pattern with good reproducibility. This step also eliminates mechanical damage to the resist film and conductive oxide film surface. Furthermore, many excellent practical effects are exhibited, such as an economical effect in which the waste loss of the suspended solution is significantly reduced. Therefore, it is useful for forming electrodes made of conductive oxide films for various display panels such as gas discharge displays, EL displays, and liquid crystal displays, for forming conductive oxide film heaters for flat heating panels, and for patterning various metal oxide films. It is extremely advantageous to apply.

[Brief explanation of drawings]

1 to 4 are cross-sectional views of main parts for explaining the conventional conductive oxide film pattern formation method step by step, and FIGS. 5 to 9 are conductive oxide film pattern formation methods according to the present invention. FIG. 2 is a cross-sectional view of a main part showing an embodiment in the order of steps. In the drawing, 21 is a glass substrate, 22 is a conductive oxide film, 22a is a conductive oxide film portion (reduced portion) exposed from the resist film 23 pattern, and 22b
2 shows an electrode pattern, 23 a resist film, 24 a metal powder layer, 25 a processing basket, 26 a processing container, and 27 a suspension solution.

Claims (1)

[Claims] 1. Conductive oxide film 22 formed on the surface of the substrate 21
is patterned in accordance with the pattern of a resist film 23 formed thereon, in which a container 26 containing a liquid 27 containing suspended metal powder that reacts with acid to generate nascent hydrogen is used. After placing the substrate 21 on which the resist film pattern 23 is formed on the liquid surface with the resist film forming surface facing upward, the container is rocked a predetermined number of times to cause the liquid in the container to form a resist film on the substrate. immersing the surface and applying metal powder in the liquid to the surface of the conductive oxide film exposed from the resist film pattern on the substrate; and reacting the metal powder layer applied on the substrate with dilute acid to remove the metal. 1. A method for forming a pattern of a conductive oxide film, comprising the steps of: reducing a portion of the conductive oxide film coated with a powder layer; and removing the reduced portion 22a by etching.