KR20130068571A - Washing method for mask used in vapor deposition step in production of organic el device - Google Patents

Abstract

PURPOSE: A method for cleaning a deposition mask used in manufacturing an organic electroluminescence (EL) device is provided to perform a mask drying process easily, by simplifying a rinse process. CONSTITUTION: Tetra Hydro Furan (THF) solution is prepared in a cleaning chamber. The THF solution has temperature of 30~60°C. An organic EL mask is precipitated into the THF solution. The THF solution where the organic EL mask is precipitated is washed with ultrasonic wave. The washed organic EL mask is washed with deionized water. [Reference numerals] (AA) Start; (BB) Inject THF in a washing chamber; (CC) Precipitate an organic EL mask in the chamber; (DD) Wash the mask using ultrasonic waves; (EE) Precipitate the mask in a deionized water chamber; (FF) Dry the mask at 80°C using an oven; (GG) End

Description

Washing method for mask used in vapor deposition step in production of organic EL device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method, and more particularly, to a cleaning method for removing an organic EL material adhering to a mask generated in a deposition process of manufacturing an organic EL device.

Flat panel displays are attracting attention as display devices therefrom, but among them, display devices having liquid crystal displays and organic EL elements are excellent. While the liquid crystal display device consumes low power, it requires external illumination (backlighter) to obtain a bright image. On the other hand, a display device having an organic EL element is a liquid crystal display because the organic EL element is a self-luminous element. Since it does not require a back lighter like a device, it can reduce power consumption and also has a high brightness and wide viewing angle.

There are two types of organic EL devices, a low molecular type organic EL device and a high molecular type organic EL device, depending on the type of the organic material. The former forms a film by the vapor deposition method, the latter melt | dissolves in a solvent, and a film is formed by the spin coating method and the inkjet method.

The low molecular organic EL device has a layered structure in the order of (1) anode, (2) hole injection layer, (3) hole transport layer, (4) light emitting layer, (5) electron transport layer, and (6) cathode on glass substrate. Is formed by vacuum deposition using a mask.

The pattern formation of these layers requires the formation of a cathode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an anode by vacuum deposition, with the mask close to the substrate, but particularly fine patterning of the RGB layer. The vapor deposition mask is highly precise and therefore difficult to manufacture, and is very expensive. However, in the formation of the pattern of the organic layer in the low molecular organic EL device, when the same mask is deposited several times, organic materials are deposited and adhered onto the mask, so that a highly precise mask pattern cannot be accurately transferred to the substrate. Therefore, in order to realize a highly precise mask pattern, the expensive mask used several times must be discarded, which is one cause of difficulty in mass production in terms of production cost. In the field of organic EL which is in the development stage, attempts and considerations for reducing the cost by repeatedly using a mask have not been made at this stage.

As a conventional technique for solving such a problem, Korean Patent Laid-Open Publication No. 10-2005-0054452 provides a cleaning liquid and a cleaning method for a mask used in a vacuum deposition process of manufacturing a low molecular organic type EL device, but rinsing after removal of the organic EL Although there is a problem that the process is complicated and requires an additional rinse liquid, Korean Patent Laid-Open No. 10-2004-0072279 provides a mask cleaning device for organic electroluminescence (EL), but to vaporize and liquefy a solvent. In order to solve this problem, the apparatus is very complicated and takes a long time to clean.

KR 10-2005-0054452 A KR 10-2004-0072279 A

The present invention aims at simplifying the mask drying process by simplifying the rinse process as well as excellent EL solubility in order to solve the above problems of the prior art.

In order to achieve the above object,

The present invention provides a method for cleaning an organic EL mask comprising the steps of: (A) providing a tetrahydrofuran (THF, Tetrahydrofuran) solution in the cleaning chamber; Depositing an organic EL mask in the THF solution (B); Ultrasonic cleaning the THF solution having the organic EL mask deposited thereon (C); And (D) washing the cleaned organic EL mask with deionized water.

The cleaning method of the organic EL mask according to the present invention not only has excellent EL solubility but also provides an effect of simplifying and simplifying the mask drying process by simplifying the rinsing process.

1 is a flowchart illustrating one embodiment of a method for cleaning an organic EL mask according to the present invention.

Hereinafter, the cleaning method of the organic EL mask according to the present invention will be described in detail.

Tetrahydrofuran (THF, Tetrahydrofuran) solution can be used as the washing | cleaning liquid of this invention. Tetrahydrofuran has excellent cleaning properties even at low temperatures and can be used as a cleaning liquid for organic EL masks without a separate heating step.

After the THF cleaning liquid is filled in the cleaning chamber, the organic EL mask is dipped in the THF cleaning liquid. At this time, the THF cleaning liquid preferably has a temperature of 30 ~ 60 ℃.

Thereafter, ultrasonic waves are applied to the THF cleaning liquid on which the organic EL mask is deposited to clean the organic EL mask. In the case of the ultrasonic cleaning, the dissolution performance is improved and the cleaning time can be shortened.

After the ultrasonic cleaning is completed, the washed organic EL mask is washed with deionized water. In the case of the present invention, the tetrahydrofuran is excellent in solubility in water, so that the organic EL mask can be washed without using a separate rinse liquid.

The organic EL mask washed with deionized water is dried in an oven. It is preferable that the temperature of the said oven is 50-100 degreeC.

Although the Example and comparative example of this invention are shown below and this invention is demonstrated in detail, this invention is not limited to these Examples.

Examples 1-6 and Comparative Examples 1-6: Cleaning of Organic EL Mask

Example 1

After filling 20 liters of THF solution as a washing | cleaning liquid in the washing | cleaning chamber in an ultrasonic processing apparatus, the mask for organic EL vapor deposition by which organic EL was deposited was immersed in THF solution of normal temperature. The organic EL deposition mask was cleaned by sonicating the THF solution in which the organic EL deposition mask on which the organic EL was deposited was deposited. The organic EL deposition mask after the cleaning was rinsed once with deionized water. The organic EL deposition mask on which the organic EL having been cleaned is deposited is rinsed with deionized water once using a spray spraying device for 30 seconds.

[Example 2]

In Example 1, it carried out by the same method as Example 1 except having performed the rinse process using deionized water twice.

[Example 3]

In Example 1, the same procedure as in Example 1 was conducted except that the rinse treatment using deionized water was performed three times.

Example 4

In Example 1, it was carried out in the same manner as in Example 1 except that the washing temperature of the THF washing liquid is 50 ℃, not room temperature.

[Example 5]

In Example 4, the same method as in Example 4 was carried out except that the rinse treatment using deionized water was performed twice.

[Example 6]

In Example 4, the same procedure as in Example 4 was carried out except that the rinse treatment using deionized water was performed three times.

Comparative Example 1

In Example 1, it was carried out in the same manner as in Example 1 except that NMP solution was used instead of THF solution as the cleaning solution.

Comparative Example 2

In Comparative Example 1, the same procedure as in Comparative Example 1 was conducted except that the rinse treatment using deionized water was performed twice.

[Comparative Example 3]

In Comparative Example 1, the same procedure as in Comparative Example 1 was conducted except that the rinse treatment using deionized water was performed three times.

[Comparative Example 4]

In the comparative example 1, it carried out by the same method as the comparative example 1 except the washing temperature of the said NMP washing liquid is 50 degreeC instead of normal temperature.

[Comparative Example 5]

In Comparative Example 4, the same procedure as in Comparative Example 4 was conducted except that the rinse treatment using deionized water was performed twice.

[Comparative Example 6]

In Comparative Example 4, the same procedure as in Comparative Example 4 was carried out except that the rinse treatment using deionized water was performed three times.

Experimental Example 1. Evaluation of Detergency and Rinseability

The metal pieces of Examples 1 to 6 and Comparative Examples 1 to 6 were subjected to ultrasonic treatment to measure the time taken for the cleaning to be completed to evaluate the cleanability. The detergency was expressed as? When the organic matter was removed within 1 minute,? When removed within 3 minutes, and? When removed within 5 minutes.

In addition, the cleaned metal pieces were immersed in a chamber filled with deionized water for 1 minute, and the organic matter remaining in the immersed deionized water was irradiated to evaluate the rinsing properties. The evaluation of the rinsing property was indicated by o when the rinse became good, and X when the rinse state was insufficient.

Cleaning solution Cleaning temperature Deionized Water Rinse Cleanliness Rinse castle Example 1 THF Room temperature 1 time ◎ ○ Example 2 Episode 2 ◎ ○ Example 3 3rd time ◎ ○ Example 4 50 ℃ 1 time ◎ ○ Example 5 Episode 2 ◎ ○ Example 6 3rd time ◎ ○ Comparative Example 1 NMP Room temperature 1 time Δ Χ Comparative Example 2 Episode 2 Δ Χ Comparative Example 3 3rd time Δ ○ Comparative Example 4 50 ℃ 1 time ○ Χ Comparative Example 5 Episode 2 ○ Χ Comparative Example 6 3rd time ○ ○

As shown in Table 1, when using a conventional NMP solution as the cleaning liquid, when the high cleaning temperature of 50 ℃ as shown in Comparative Examples 4 to 6, the washability is relatively good, but as in Comparative Examples 1 to 3 It is understood that at room temperature, the washability is poor, and a heating step of the cleaning liquid is required prior to cleaning. In addition, in Comparative Examples 1 to 6 there is a problem that the rinsing process is not simple because it shows good rinsing properties only when the deionized water is washed three or more times.

On the contrary, in Examples 1 to 6, both the cleanability and the rinse property are good at room temperature and 50 ° C.

Claims (2)

Providing a tetrahydrofuran (THF, Tetrahydrofuran) solution in the cleaning chamber (A);
Depositing an organic EL mask in the THF solution (B);
Ultrasonic cleaning the THF solution having the organic EL mask deposited thereon (C); And
And washing the cleaned organic EL mask with deionized water (D). The method according to claim 1, wherein the THF solution is a room temperature cleaning method of an organic EL mask.

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