KR20060062866A - Etchant composition for indium zinc oxide layer and etching method using the same - Google Patents

Abstract

The etching liquid composition of the IZO membrane according to the present invention is characterized in that it comprises 1 to 15% by weight of sulfuric acid and the residual amount of water.

When the etching solution composition of the present invention is used, there is no attack on photoreactive materials such as photoresist during the etching process, and there is no effect on the occurrence of residues and the underlying film after the etching process. The productivity can be improved.

IZO membrane, etchant composition

Description

Etch Liquid Composition of Indium Zinc Oxide and Etching Method Using The Same {ETCHANT COMPOSITION FOR INDIUM ZINC OXIDE LAYER AND ETCHING METHOD USING THE SAME}

Figure 1 shows the profile after etching the IZO membrane with an etchant according to the etchant composition of the present invention.

The present invention relates to an etching liquid composition capable of effectively etching an indium oxide film, particularly an indium zinc oxide (hereinafter referred to as "IZO") film, which is stacked on various electronic component circuit boards and used as a transparent electrode.

In the present invention, IZO refers to an oxide in which In ₂ O ₃ and ZnO are mixed at an appropriate ratio. The IZO transparent electrode is generally laminated on a glass substrate or the like by sputtering or the like, and then coated with a photoresist thereon, forming a pattern through an exposure and developing process, and then forming an IZO film. Etching forms a transparent electrode.

An indium zinc oxide film is a material that is not easily etched by a chemical reaction due to its excellent chemical resistance, and an example of an etchant that has been conventionally used to etch an indium zinc oxide film is aqua regia system disclosed in Korean Patent Publication No. 96-2903. (HCl + HNO ₃ ) etchant; An etchant consisting of one substance selected from hydrochloric acid, weak acid and alcohol described in Korean Laid-Open Patent Publication No. 97-65685; Iron chloride based (FeCl ₃ + HCl) etchant described in US Pat. No. 5,456,795; Oxalic acid described in Korean Laid-Open Patent Publication No. 2000-0017470, and an etchant having a salt or aluminum chloride thereof as a main component. U. S. Patent No. 5,340, 491 also discloses an etchant containing hydrogen iodide (HI) and iron chloride (FeCl ₃ ).

In addition, in Journal of the Electrochemical Society, Vol. 122, No. 122, 1975, "Properties of Sn-Doped In ₂ O ₃ films prepared by RF sputtering" by John CC Fan and Frank J. Bachner, et al. Concentrated sulfuric acid (conc. H ₂ SO ₄ , 96-98%) was used.

However, in the case of aqua regia solution, although the price of the etchant is cheap, there is a problem that the etching solution composition is large, because the etching of the pattern side is large, and the hydrochloric acid or nitric acid is volatilized after forming the etchant. In addition, even in the case of the iron chloride-based etching solution, there is a problem that the fluctuation of the components appear the same as the aqua regia system, since hydrochloric acid is the main etching solution. In addition, even though the etching solution made of oxalic acid is easy to etch, there is a problem in that precipitates are formed at low temperatures due to low solubility. In addition, in the case of the HI-based etching solution, the etching rate is high and the side etching is low, but the cost is high, the toxicity and corrosiveness are high, and the concentrated sulfuric acid affects the photoresist, resulting in uneven etching of the profile. There is a limit to use in the actual process.

On the other hand, in the case of conventional etching liquids, most of them have strong chemical activity, and may cause erosion of adjacent metals such as molybdenum, aluminum, and chromium having low chemical resistance during etching. For example, in the case of a TFT-LCD, many restrictions are placed on the selection of a material forming another film.

Furthermore, in the case of the etching liquid containing hydrochloric acid, there is a smoke, causing a problem of air pollution due to the fume (fume), thereby increasing the cost of equipment and problems of safe operation.

Accordingly, an object of the present invention is to provide a selectivity ratio with other films during etching of an IZO film laminated on an electronic component substrate or the like (i.e., an index indicating the influence on the film quality other than the IZO film. The ratio of the amount of etching) and to improve the reproducibility of the etching process, there is no generation of fumes, and to provide an etching liquid composition with high stability of the liquid with temperature.

In order to achieve the above object, the etching liquid composition of the IZO transparent conductive film according to the present invention is characterized in that using a sulfuric acid of a specific composition, more specifically 1 to 15% by weight of sulfuric acid and the remaining amount of water It is done.                     

In the compositions according to the invention, sulfuric acid used as the main oxidizing agent can be prepared according to commonly known methods, and it is particularly preferred to have a purity for semiconductor processing.

The water suitable for use in the etching liquid composition of the IZO membrane according to the present invention is not particularly limited, but preferably has a specific resistance value of deionized water, particularly preferably water of 18 dl / Deionized water of at least cm is used.

On the other hand, the etching liquid composition according to the present invention may contain any additives commonly used in the art in order to improve the etching performance. Although it does not specifically limit as an example of the said additive, In general, surfactant, a metal ion blocking agent, a corrosion inhibitor, etc. can be used. Surfactants may be added to the etchant composition to lower the surface tension to increase the uniformity of the etch, and as a preferred example of such a surfactant, a surfactant that is tolerant and compatible with the etchant, such as any anionic And cationic, amphoteric or nonionic surfactants. Also, preferably, a fluorine-based surfactant may be added to the etching solution composition according to the present invention as the surfactant.

In addition to the above, those skilled in the art can select various other additives which are obviously known in the art, in order to further improve the effect according to the present invention.

The additive may be added in the range of preferably 0.0001% by weight to 0.01% by weight based on the total weight of the composition.

The etching liquid composition according to the present invention, by using sulfuric acid of a specific composition, has an excellent etching performance for the IZO film used for electronic component substrates, etc., reduces the attack of the photoresist which is a photoreactive material during the etching process, and residues Has excellent properties not to leave. In addition, the etchant composition according to the present invention does not have a crystallization phenomenon of oxalic acid at 0 ° C. or less, which is known as a problem of conventional oxalic acid-based etching solutions, and does not affect the lower metal film appearing in the hydrochloric acid-based etching solution. Therefore, productivity can be improved in the manufacturing process of electronic components, such as a display apparatus using an IZO film | membrane.

On the other hand, the present invention also provides an etching method of the IZO film. The method according to the invention comprises the following steps:

1) forming an indium oxide film, in particular an IZO film, on an electronic component substrate;

2) selectively leaving a photoresist on the indium oxide film; And

3) etching using the etchant composition of the present invention.

Among the above methods, step 1 may include fabricating a display device structure, in particular a liquid crystal display device substrate, on a substrate and depositing an IZO film on the display device structure, in particular a liquid crystal display device substrate. .

The substrate in step 1) is usually a glass substrate, a quartz substrate, or the like, which is mainly used for a display device, and is preferably a glass substrate. On a substrate, an IZO film is prepared by a method generally known to those skilled in the art, for example by sputtering, for example, having a thickness of approximately 600 to 200 kPa. Meanwhile, a structure for a display device may be added between the substrate and the IZO film. The structure for a display device includes one or more films from a conductive film, such as an organic insulating film, a sputtering method, or a semiconductor film, such as an amorphous or polycrystalline silicon film, by a chemical vapor deposition method, or the like. It means a manufactured structure. It is also possible to carry out a conventional cleaning process on the substrate and deposit an IZO film.

In the step 2), the "optionally" substrate is coated with a photoreactive material such as a photoresist, irradiated to a predetermined region using a photomask, and then developed to form an etching pattern in the selected region. it means.

That is, in order to form an indium zinc oxide film on a selective site on the substrate, a photoreactive material (for example, a photoresist) is coated and selectively exposed using a mask to partially remove the photoreactive material with a developer. Done. For example, the photoresist is coated with a spin coater and coated with a thickness of about 1 μm. The photoreactive material may be a cathode or an anode reactant. In such a process, a conventional process such as ashing or heat treatment may also be added.

The etching process in step 3) may be performed according to a method well known in the art, and exemplifies dipping, spraying, and the like. The temperature of the etching solution in the etching process is 20 ~ 50 ℃, the appropriate temperature can be changed as needed by other processes and other factors.

Hereinafter, embodiments according to the present invention will be described in detail. These examples are merely illustrative of the present invention, but are not limited thereto, and it is apparent to those skilled in the art that various modifications are possible.

Examples 1-6

An IZO substrate was prepared. Sulfuric acid, a grade for semiconductor processing, was mixed with deionized water in the amounts listed in Table 1 below to prepare 180 kg of an etchant. An etching solution prepared in a spray etching test apparatus (manufactured by KDNS, model name: ETCHER (TFT)) was added thereto, heated to 40 ° C., and then etched when the temperature reached 40 ± 0.5 ° C. . O / E (Over Etch) was performed at 30% based on EPD (End Point Detection) of the pad portion. The substrate was inserted and spraying was started, and when the etching was completed, the substrate was taken out, washed with deionized water, dried using a hot air drying apparatus, and removed using a photoresist (PR) stripper. After washing and drying, an electron scanning microscope (SEM; manufactured by HITACHI, model name: S-4700) was used to evaluate the presence or absence of residues, photoresist attack, and the like. The results are shown in Table 1.

Example Membrane Sulfuric acid / deionized water Poor etching Residue Photoresist attack One IZO 1/99 X X X 2 3/97 X X X 3 5/95 X X X 4 7/93 X X X 5 10/90 X X X 6 15/85 X X X

Composition: weight%

Attack: Indicates a change in pattern.

The etching liquid compositions of the IZO film having the sulfuric acid content having the weight% defined in Examples 1 to 6 of the present invention showed a good etching state without affecting the photoresist, and partial etching failure and no metal etching residue. .

Comparative Examples 1 and 2

The performance was evaluated by etching in the same manner as in Examples 1 to 6, except that an etching solution prepared by combining sulfuric acid and deionized water at the weight% shown in Table 2 was used. The results are shown in Table 2.

Comparative example Membrane Sulfuric acid / deionized water Poor etching Residue Photoresist attack One IZO 0.1 / 99.9 Partial etch failure 0 X 2 30/70 Bad profile X O (tear phenomenon)

Composition: weight%

It can be seen that the etching liquid compositions of Comparative Examples 1 to 2, in which the content of each component does not have a weight percent defined in the present invention, exhibit problems such as partial etching failure, metal etching residue generation, and poor profile due to photoresist attack. have.

As described above, the etchant composition according to the present invention has no attack on photoreactive materials such as photoresist during the etching process, and does not affect residue generation and underlying layers after the etching process. Productivity can be improved in manufacture.

Claims (1)

1 to 15% by weight sulfuric acid and the balance of water, based on 100% by weight of the total composition.

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