JP2014143266A - Etching composition and etching method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etching composition and an etching method capable of etching a metal film made of silver or a silver alloy and crystalline ITO (indium tin oxide) with a single liquid and at an industrially satisfactory speed.
SOLUTION: As a composition for etching a metal film made of silver or a silver alloy and a crystalline transparent conductive film in one liquid, hydrobromic acid, hydrogen peroxide, a surfactant, and water as a remaining component A composition containing is used.
[Selection figure] None

Description

  The present invention relates to an etching composition for etching a metal film made of silver or a silver alloy and crystalline ITO in a single solution, and a method for etching a metal film made of silver or a silver alloy and crystalline ITO using the same. .

  More specifically, an etching composition used when etching a metal film made of silver or a silver alloy on a substrate and a transparent conductive film in a manufacturing process of a thin film transistor used for a flat panel display, a memory integrated circuit, and the like, and The present invention relates to an etching method using the same.

  In recent years, with the rapid development of information technology, in electrode wiring materials used as flat panel displays and memory integrated circuits, the demand for finer processing precision has been increasing, while high light reflectance, As metals having a low resistance value, the use of silver and silver alloys is increasing. In addition, it is becoming common to use a metal film made of silver or a silver alloy by being laminated on a transparent conductive film.

  In order to form an electrode wiring made of a metal film made of silver or a silver alloy and a transparent conductive film, it is necessary to process them into a predetermined pattern shape. As a processing technique for forming this pattern, etching using chemicals is known. For example, ferrous chloride / hydrochloric acid aqueous solution, aqua regia and hydrobromic acid aqueous solution are used for etching of crystalline ITO in transparent conductive film, and organic acid such as oxalic acid is used for etching of amorphous ITO. An etching composition is used. On the other hand, for etching a metal film made of silver or a silver alloy, a mixed acid made of phosphoric acid, nitric acid and acetic acid is used. Etching of a transparent conductive film and a metal film made of silver or a silver alloy with two liquids Was common. However, this method is not economical because two types of chemicals are required and two etching apparatuses are required.

  Therefore, a method of simultaneously etching a metal and a transparent conductive film with one mixed acid solution composed of phosphoric acid, nitric acid and acetic acid (see, for example, Patent Document 1), or adding oxalic acid to a mixed acid composed of phosphoric acid, nitric acid and acetic acid. A method of etching ITO (indium oxide, tin) and a silver alloy with a single solution has been proposed (see, for example, Patent Document 2), but none of them can etch crystalline ITO. In addition, the present inventors have proposed an etching composition containing 0.01 to 10% by weight of hydrobromic acid and a fluorine compound (see, for example, Patent Document 3), which is also amorphous ITO. It is intended for this etching, and crystalline ITO cannot be etched. On the other hand, an etching composition containing copper ions, nitric acid, and a fluorine compound has been proposed as a composition capable of etching a metal film made of crystalline ITO and silver or a silver alloy in a lump (see, for example, Patent Document 4). ) Etching of crystalline ITO depends on a small amount of fluorine compound, and it may be difficult to control the etching rate due to fluctuations in fluorine concentration, and it cannot be used when a glass substrate is used because the glass corrodes.

JP 2004-156070 A JP 2007-7982 A JP 2010-67826 A JP 2009-206462 A

  The present invention has been made in view of the above-described background art, and an object thereof is to provide an etching composition capable of etching a metal film made of silver or a silver alloy and crystalline ITO, which is a transparent conductive film, in a single solution, and It is to provide an etching method using the same.

  As a result of intensive studies on an etching method between a metal film made of silver or a silver alloy and crystalline ITO, which is a transparent conductive film, the present inventors have found that hydrobromic acid, hydrogen peroxide, a surfactant, and the remaining components. As a result, the present inventors have found a novel fact that an etching composition containing water can etch a metal film made of silver or a silver alloy and crystalline ITO with a single solution as an etching composition, and completed the present invention. It was.

  That is, the present invention is an etching composition and an etching method using the same as shown below.

  [1] An etching composition comprising hydrobromic acid, hydrogen peroxide, a surfactant, and water as a remaining component.

  [2] 30 wt% to 46 wt% hydrobromic acid, 0.1 wtppm to 1 wt% hydrogen peroxide, 0.01 wtppm to 100 wtppm surfactant and water as the remaining component The etching composition as described in [1], which is contained.

  [3] The etching composition as described in [1] or [2], wherein the surfactant is a polyoxyalkylene alkyl ether surfactant.

  [4] Using the etching composition according to any one of [1] to [3], a metal film made of silver or a silver alloy and a crystalline transparent conductive film are etched in one liquid. Etching method to do.

  [5] The etching method according to [4], wherein the transparent conductive film is ITO (indium tin oxide).

  [6] The silver alloy is an alloy of silver with one or more metals selected from the group consisting of copper, palladium, platinum, ruthenium, and gold, according to [4] or [5] Etching method.

  According to the present invention, a metal film made of silver or a silver alloy and crystalline ITO can be etched with one liquid without exchanging the liquid, and even if used at a low temperature of 35 to 40 ° C., it is industrial. Can be etched at a rate satisfying the above.

  Therefore, the present invention is extremely useful industrially because it can make it possible to efficiently manufacture flat panel displays and memory integrated circuits.

  The essential components of the etching composition of the present invention are hydrobromic acid, hydrogen peroxide, a surfactant and water.

  Hydrobromic acid that can be used in the etching composition of the present invention contributes to the etching of crystalline ITO and the etching of a metal film made of silver or a silver alloy. There is no restriction | limiting in particular in hydrobromic acid, The hydrobromic acid aqueous solution currently distribute | circulated industrially can be used. Hydrobromide may be added for the purpose of suppressing pH fluctuation. Examples of the hydrobromide include ammonium salt and amine salt of hydrobromic acid.

  In the etching composition of the present invention, hydrogen peroxide has the effect of increasing the etching rate of a metal film made of silver or a silver alloy. There is no restriction | limiting in particular in the hydrogen peroxide used for the etching composition of this invention, The hydrogen peroxide aqueous solution currently distribute | circulated industrially can be used.

  In the etching composition of the present invention, a surfactant is contained in order to achieve etching uniformity. Surfactants such as cationic, anionic, and nonionic surfactants can be used without problems if they are generally distributed, and those that do not contain alkali metals are preferred for use in electronic materials. Polyoxyalkylene alkyl ether surfactants Agents are particularly preferred. This surfactant is generally distributed for electronic materials. By adding the surfactant to the composition of the present invention, the etching composition penetrates into the fine pattern, thereby enabling more uniform etching.

  In the etching composition of the present invention, hydrobromic acid, hydrogen peroxide and a surfactant are used as an aqueous solution.

  The etching composition of the present invention has a hydrobromic acid content of 30% to 46% by weight and hydrogen peroxide content of 0.1% with respect to the entire etching composition from the viewpoint of the etching rate and the degree of side etching. The range of ppm by weight to 1% by weight and the range of 0.01 to 100 ppm by weight of surfactant are preferred, and water is contained as the remaining component. More preferably, hydrobromic acid is in the range of 35 wt% to 46 wt%, hydrogen peroxide is in the range of 1 to 1000 wtppm, the surfactant is in the range of 0.1 wtppm to 10 wtppm, and the balance Contains water as a component of

  The etching composition of the present invention is applied to the surface of a substrate in a manufacturing process of a thin film transistor used for an electronic device, particularly a flat panel display (for example, an active matrix liquid crystal display, an organic EL display, etc.) Excellent performance when etching the formed silver or silver alloy thin film.

  Next, the etching method of the present invention will be described. The etching method of the present invention uses the etching composition of the present invention, and uses thin film transistors used for electronic devices, particularly flat panel displays (for example, active matrix liquid crystal displays, organic EL displays) and memory integrated circuits. In this manufacturing process, a metal film made of silver or a silver alloy and a transparent conductive film made of crystalline ITO are etched together. For example, a transparent conductive film is laminated on a metal film made of silver (silver alloy) even on a substrate on which a metal film made of silver (silver alloy) and a transparent conductive film are exposed at the same time. If the etching composition of the present invention is used for a substrate on which a metal film made of an alloy is not exposed, both the metal film made of silver (silver alloy) and the transparent conductive film can be etched. . Examples of the silver alloy include an alloy of silver and one or more metals selected from the group consisting of copper, palladium, platinum, ruthenium, and gold.

  Since the etching composition of the present invention has very high etching performance when etching, it can be used sufficiently even at a low temperature. As the use temperature, from the viewpoint of etching rate and evaporation of water and hydrobromic acid, The range of 20-80 degreeC is preferable, More preferably, it is the range of 30-60 degreeC, Most preferably, it is the range of 35-50 degreeC.

  When etching a metal film made of silver or a silver alloy and a crystalline transparent conductive film using the etching composition in the etching method of the present invention, both batch type and single wafer type should be used without any problem. It is also possible to use spray spray cleaning or other methods. Moreover, in order to accelerate etching and remove residues, ultrasonic waves or the like may be used during etching. As the rinsing after etching, it is not necessary to use an organic solvent such as alcohol, and it is sufficient to rinse with water.

  The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto.

  In order to simplify the notation, the following abbreviations are used.

APC: Silver-palladium-copper alloy ITO: Crystalline ITO (indium oxide-tin transparent conductive film)
HBr: Hydrobromic acid (Kishida Chemical Co., Ltd.)
HPO: Hydrogen peroxide (ADEKA Corporation)
POAE: Polyoxyalkylene alkyl ether surfactant (Wako Pure Chemical Industries)
Example 1 to Example 5. Comparative Example 1 to Comparative Example 2
The etching composition (etching solution) shown in Table 1 was prepared (the balance being water). A glass substrate in which an APC thin film (film thickness 0.2 μm) was formed on crystalline ITO (film thickness 40 nm) was immersed in this etching solution at the temperature shown in Table 1. The time when both APC and ITO films were completely etched and disappeared was measured. The results are shown in Table 1.
In addition, it was set as (circle) when there was no residue and x when the residue was seen.

  As is clear from Table 1, the etching compositions of the examples can be etched without the step and residue between ITO and APC by reducing the etching time as compared with the etching compositions of the comparative examples.

Claims (6)

An etching composition comprising hydrobromic acid, hydrogen peroxide, a surfactant, and water as a remaining component. 30 wt% to 46 wt% hydrobromic acid, 0.1 wtppm to 1 wt% hydrogen peroxide, 0.01 wtppm to 100 wtppm surfactant and water as the remaining component. The etching composition according to claim 1. The etching composition according to claim 1 or 2, wherein the surfactant is a polyoxyalkylene alkyl ether surfactant. An etching method comprising etching a metal film made of silver or a silver alloy and a crystalline transparent conductive film with one liquid using the etching composition according to claim 1. The etching method according to claim 4, wherein the transparent conductive film is ITO (indium tin oxide). The etching method according to claim 4 or 5, wherein the silver alloy is an alloy of one or more metals selected from the group consisting of copper, palladium, platinum, ruthenium and gold and silver.