KR102546796B1 - Etchant composition - Google Patents

Abstract

The etchant composition according to the present invention contains nitric acid, a compound having 4 to 8 carbon atoms while containing a carboxyl group, a cyclic amine compound, and water in specific amounts, thereby preventing silver ion reduction and controlling residue and over-erosion. can do.

Description

Etch composition {ETCHANT COMPOSITION}

The present invention relates to an etchant composition capable of preventing residue and over-erosion from occurring.

[0003] As display panels have become larger in size and higher in resolution, the number of pixels in which pixel electrodes are formed is also increasing. In order to form a large number of pixel electrodes in a limited space, it is necessary to reduce the size of the pattern forming the pixel electrodes. However, since there is a limit to simply reducing the size of the pattern, the etching rate of the pixel electrodes is adjusted to reduce the size of the pixel electrodes. A method of forming is also used. Meanwhile, a thin film transistor (TFT) circuit for driving the pixel electrode is overlapped with the pixel electrode. Here, the pixel electrode is generally made of an indium oxide film, and the gate and source-drain electrodes of the thin film transistor overlapping the pixel electrode are made of a metal film such as molybdenum, titanium, copper, silver, or aluminum.

At this time, aluminum is generally used as the metal film. Pure aluminum has weak corrosion resistance to chemicals and may cause wiring defects in subsequent processes. To compensate for this, aluminum alloy is used or aluminum or aluminum alloy is Another metal layer, for example, may use a multi-layer stacked with metal layers such as molybdenum, chromium, tungsten, and tin.

However, in recent years, the demand for high resolution and large size of the liquid crystal display device has increased, and in order to realize this, research to use a metal film having a lower resistance than aluminum has been continued. Accordingly, a technique of forming a wire using silver (resistivity: 1.59 μΩ cm) having a lower resistance than aluminum (resistivity: 2.65 μΩ cm) has been progressing.

In addition, the indium oxide film used as the pixel electrode has relatively excellent light transmittance and conductivity, and is, for example, an indium zinc oxide (hereinafter referred to as 'IZO') film or an indium tin oxide (Indium Tin Oxide) film. , hereinafter referred to as 'ITO') films and the like.

A method of forming a pixel electrode with such an indium oxide film is to prepare an indium oxide film (IZO film or ITO film) on a glass substrate using a sputtering method, coat photoresist thereon, and perform exposure and development processes. After forming a pattern through, the indium oxide film is etched to form an electrode.

However, when etching a relatively thin indium oxide film with a thickness of less than 100 Å or etching a double layer of a metal film and an indium oxide film, a tip of the metal film may occur, and defects such as a taper angle may occur, and chemical reactions may occur. As it is a material that is not easily etched, there is a problem of generating precipitates such as residues and residual films.

Republic of Korea Patent Publication No. 10-2012-0093499 relates to a non-halogen etchant for indium oxide film and a method for manufacturing a display substrate using the same, wherein the non-halogen etchant is nitric acid, sulfuric acid, a corrosion inhibitor including ammonium, and a cyclic amine compound and water.

However, in the prior literature, when etching an indium oxide film having a thickness of 100 Å or less, overetching defects and residues may occur, or when etching a multilayer film of a silver alloy film and an indium oxide film, poorly soluble silver sulfide may be generated by sulfuric acid in the etchant. There is a problem with

Republic of Korea Patent Publication No. 10-2012-0093499 (2015.03.09. Dongwoo Fine-Chem Co., Ltd.)

The present invention is to solve the above problems, and it is possible to prevent residue and excessive erosion by including nitric acid, a compound having 4 to 8 carbon atoms including a carboxyl group, a cyclic amine compound, and water in specific amounts. The purpose is to provide an etchant composition that can be.

An etchant composition according to the present invention for achieving the above object includes 5 to 10% by weight of nitric acid; 0.1 to 5% by weight of a compound having 4 to 8 carbon atoms including a carboxyl group; 0.1 to 5% by weight of a cyclic amine compound; And characterized in that it comprises a residual amount of water.

As described above, the etchant composition according to the present invention includes nitric acid, a compound containing a carboxyl group and having 4 to 8 carbon atoms, a cyclic amine compound, and water in a specific amount, thereby preventing residue and excessive erosion. It works.

1 shows SEM images showing the presence/absence of etching/residue, over-erosion, and damage to the lower film according to the etchant compositions of Examples 1, 2, Comparative Example 1, and Comparative Example 4.

The etchant composition according to the present invention selectively etches an indium oxide film in a multi-layer thin metal layer composed of silver and an indium oxide film, 5 to 10% by weight of nitric acid; 0.1 to 5% by weight of a compound having 4 to 8 carbon atoms including a carboxyl group; 0.1 to 5% by weight of a cyclic amine compound; And characterized in that it comprises a residual amount of water.

The multi-layer thin metal layer of the present invention includes an indium oxide film among the components of the film, and includes a single film of the indium oxide film; and a multilayer film composed of at least one film selected from silver and silver alloy films and an indium oxide film. Examples of the multilayer film include double or triple films such as a silver/indium oxide film, a silver alloy film/indium oxide film, an indium oxide film/silver alloy film/indium oxide film, and the like.

The nitrate is a main component for etching the indium metal oxide film containing indium, and may play a role of wet etching by oxidizing the indium oxide film, and may minimize the generation of residues of the indium oxide film.

It is preferable to include 5 to 10% by weight based on the total weight% of the silver nitrate etchant composition, and if the content of nitric acid is less than the above range, the metal oxide film containing indium may not be etched or the etching rate is very slow, and the above range If it is exceeded, the etching rate increases overall, but it becomes difficult to control the etching process, or the total amount of nitric acid increases, which may increase the amount of wastewater treatment.

The compound having 4 to 8 carbon atoms including a carboxyl group can control over-erosion of the upper and lower indium oxide layers in the double or triple layer including the silver alloy layer while removing residues of the indium oxide layer. At this time, if the carbon number is less than 4, the effect of removing the residue may be effective, but over-erosion control may not be possible, and if the carbon number exceeds 8, the etching rate of the indium oxide film may be significantly reduced.

At this time, the compound having 4 to 8 carbon atoms including a carboxyl group is tartaric acid, malic acid, maleic acid, citric acid, succinic acid and adipic acid. It is preferable to include at least one or more from the group consisting of (adipic acid).

It is preferable to include 0.1 to 5% by weight of the compound having 4 to 8 carbon atoms including the carboxyl group based on the total weight% of the etchant composition, and when the compound having 4 to 8 carbon atoms including the carboxyl group is less than the above range, the indium oxide film If the indium oxide film is on the upper part due to excessive erosion, the photoresist may be separated, or the metal film may be lifted when the indium oxide film is on the lower part. In addition, when the compound having 4 to 8 carbon atoms including a carboxyl group exceeds the above range, the etching rate of the indium oxide film may be slowed down.

The cyclic amine compound can reduce the rate of damage to the lower layer that can be caused by the etchant when there is a lower layer of copper, aluminum, molybdenum, titanium, etc. under the layer to be etched with the etchant.

The cyclic amine compound is a pyrrole-based, pyrazole-based, imidazole-based, triazole-based, tetrazole-based, pentazole-based, oxazole ( It is preferable to include at least one selected from the group consisting of oxazole, isoxazole, thiazole, and isothiazole. Moreover, as a triazole type, it is more preferable that it is 1 or more types chosen from benzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, and tolytriazole. The tetrazole type is more preferably at least one selected from 3-methyltetrazole, 3-aminotetrazole, 5-methyltetrazole and 5-aminotetrazole. Further, in the present invention, benzotriazole is most preferred.

The cyclic amine compound preferably includes 0.1 to 5% by weight based on the total weight% of the etchant composition, and when the cyclic amine compound is less than the above range, it is difficult to lower the rate of damage to the lower film. Since the etching power of the indium oxide film is reduced in the case of the indium oxide film, the generation rate of residue after etching the indium oxide film may be increased, and the etching rate may be reduced.

The water is preferably deionized water, and it is more preferable to use deionized water having a specific resistance value of 18 MΩ·cm or more, which shows the degree to which ions are removed from the water.

The water is preferably included in a residual amount based on the total weight % of the etchant composition.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to explain the present invention in more detail, and the scope of the present invention is not limited by the following examples. The following examples may be appropriately modified or changed by those skilled in the art within the scope of the present invention. In addition, "%" and "parts" indicating content below are based on weight unless otherwise specified.

Example 1 to 5 and comparative example 1 to 8

10 kg of an etchant composition containing the ingredients and compositions (% by weight) of Table 1 was prepared.

Experimental example

An etching process was performed using the etchant compositions of Examples 1 to 5 and Comparative Examples 1 to 8, respectively. The etching process used spray etching type experimental equipment (model name: ETCHER (TFT), SEMES), the temperature of the etchant composition during the etching process was set to 40 ° C, and the total etching time was 40 seconds in the etching process.

The profile of the metal film etched in the etching process was inspected using a cross-sectional SEM (manufactured by Hitachi, model name: S-4700).

In the case of the indium oxide film used in the etching process, a-ITO single film was used for the presence or absence of etching and residue. In addition, over-erosion was determined by etching the upper a-ITO and silver (Ag) of the a-ITO/Ag/a-ITO triple layer and then etching the lower a-ITO with the etchant of the present invention. Finally, damage to the lower film was determined by etching the titanium (Ti) and aluminum (Al) metal films for 5 minutes.

At this time, the presence or absence of etching, residue, over-erosion, and damage to the lower film were all visually confirmed, and the evaluation criteria were as follows, and are listed in Table 2 below.

<Evaluation Criteria>

Etching presence or absence

○: The formation of wiring can be confirmed in the SEM picture

X: The formation of wiring could not be confirmed in the SEM picture (no wiring was formed)

residue

○: Residues of the indium oxide film remain in the part (etching part) other than the wiring part in the SEM picture

X: In the SEM picture, the part (etching part) that is not the wiring part is clean with no residue of the indium oxide film.

overerosion

○: In the SEM picture, a-ITO on the top and bottom of the a-ITO/Ag/a-ITO triple layer is over-etched, causing the Ag film to be lifted.

X: In the SEM picture, the upper and lower a-ITO of the a-ITO/Ag/a-ITO triple layer is not overetched.

lower membrane damaged

○: Al of the Ti/Al/Ti triple film is etched in the SEM picture

X: Al in the Ti/Al/Ti triple film is not etched in the SEM picture

Referring to Table 2 and Figure 1 below, it can be seen that all of Examples 1 to 5 were etched, no residue was generated in the a-ITO single layer, and neither over-erosion nor damage to the lower layer occurred. .

However, in the case of Comparative Example 1, although the a-ITO single layer was not etched, it can be seen that over-erosion or damage to the lower layer did not occur. In addition, in the case of Comparative Example 2, it can be seen that residues were generated in the a-ITO single film, and the metal film was lifted due to the occurrence of over-erosion at the bottom. In addition, it can be seen that in Comparative Examples 3 to 8, at least one of residue, over-erosion, and lower film damage occurred.

Claims (8)

5 to 10% by weight of nitric acid;
0.1 to 5% by weight of a compound having 4 to 8 carbon atoms including a carboxyl group;
0.1 to 5% by weight of a cyclic amine compound; and
Including the residual amount of water,
The compound having 4 to 8 carbon atoms including a carboxyl group includes at least one from the group consisting of tartaric acid, malic acid, maleic acid, citric acid, succinic acid and adipic acid,
The etchant composition is an etchant composition, characterized in that for selectively etching the indium oxide film in a multilayer film comprising at least one film selected from silver and silver alloy films and an indium oxide film. delete According to claim 1,
The cyclic amine compound is
Pyrrole, pyrazole, imidazole, triazole, tetrazole, pentazole, oxazole, isoxa An etchant composition comprising at least one selected from the group consisting of isoxazole, thiazole, and isothiazole. According to claim 3,
The triazole type
An etchant composition comprising at least one selected from the group consisting of benzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, and tolytriazole. According to claim 3,
The tetrazole system
An etchant composition comprising at least one selected from the group consisting of 3-methyltetrazole, 3-aminotetrazole, 5-methyltetrazole and 5-aminotetrazole. According to claim 1,
The water is an etchant composition, characterized in that deionized water. delete delete

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