KR20130024590A - Mask for manufacturing thin film and method of cleaning the same - Google Patents

Abstract

PURPOSE: A mask for manufacturing a thin film and a method for cleaning the same are provided to easily remove a foreign substance deposited on a mask by using a lift off method. CONSTITUTION: A mask pattern(300a) has a blocking part and an opening part. A mask is adhered on the mask pattern. The mask includes a film(300b) having alkali solubility. Cleaning solution(500) dissolves the film. A foreign substance(400) deposited on the film is lifted off.

Description

Thin film forming mask and cleaning method thereof {MASK FOR MANUFACTURING THIN FILM AND METHOD OF CLEANING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming mask, and more particularly, to a thin film forming mask and a cleaning method thereof capable of removing foreign substances deposited on the thin film forming mask without damaging the thin film forming mask.

Recently, with the development of the information society, the demand for a display device for outputting image information is increasing in various forms. Accordingly, a liquid crystal display (LCD) is used instead of a conventional CRT (Cathode Ray Tube). ), Flat panel displays such as plasma display panels (PDPs), organic luminescent emission diodes (OLEDs), and vacuum fluorescence displays (VFDs). have.

In particular, the organic light emitting diode display uses an organic light emitting layer, which is a self-luminous device that emits phosphors by recombination of electrons and holes, and has excellent display characteristics such as contrast ratio and response time. It is easy to implement a flexible display, attracting attention as the most ideal next-generation display among the flat panel display.

Hereinafter, an organic light emitting diode display will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a general organic light emitting display device.

As shown in FIG. 1, a general organic light emitting display device includes a substrate 10, an organic light emitting display device 20 formed on the substrate 10, and a capping layer 30 capping the organic light emitting display device 20. . The organic light emitting diode display 20 includes an anode 20a, an organic light emitting layer 20b, and a cathode 20c.

In the organic light emitting diode display 20, when a voltage is applied to the anode 20a and the cathode 20c through a pad portion (not shown) formed in the non-pixel region of the substrate 10, holes are formed in the anode 20a. Electrons are injected into the organic light emitting layer 20b from the cathode 20c. The light emitted by the binding energy when the electrons and holes injected into the organic light emitting layer 20b combine with each other.

In particular, the organic light emitting diode display 20 further includes a hole injection layer (HTL) and a hole injection layer (HIL) between the organic light emitting layer 20b and the anode 20a. An electron injection layer (EIL) and an electron injection layer (ETL) are further provided between the electrode 20b and the cathode 20c to easily inject holes and electrons into the organic light emitting layer 20b.

Meanwhile, the cathode 20c and the organic light emitting layer 20b of the organic light emitting diode display 20 as described above are formed using various masks such as a photo mask and a metal mask. For example, since the cathode 20c is formed only in the pixel region except for the pad portion, the cathode 20c is formed by depositing a metal material such as aluminum (Al) using a mask having an opening in a region corresponding to the pixel region. In addition, since the organic light emitting layer 20b is made of an organic material having poor chemical resistance, the organic light emitting layer 20b is formed by vaporizing an organic material rather than a photolithography method using general exposure and etching, and then selectively depositing it on a substrate using a mask. do.

However, when the metal material or the organic material is deposited using the mask, the organic material or the metal material is deposited on the surface of the mask, and the organic material or the metal material deposited on the mask may damage the accuracy of the mask and cause a thin film pattern defect. . Therefore, after a certain number of processes, the mask should be cleaned to remove foreign substances such as organic materials or metal materials.

FIG. 2 is a cross-sectional view illustrating a method of cleaning a mask for forming a thin film, in which a foreign material is deposited, wherein the foreign material may be a metal material or an organic material as described above.

As shown in FIG. 2, in the general mask cleaning method, the mask 30 having the foreign matter 40 deposited in the cleaning tank 60 containing the cleaning liquid 50 is dipped. Then, the foreign matter 40 is dissolved in the cleaning liquid 50 to remove the foreign matter 40 from the mask 30.

However, in general, since the mask 30 is formed of a metal material and the foreign material 40 is a metal material, since the cleaning liquid 50 may be used to remove the metal material, only the foreign material 40 may be formed by the cleaning liquid 50. The mask 30 may also be dissolved. Therefore, it is difficult to selectively remove only metal material during cleaning.

Furthermore, in recent years, since the cathode is formed of various metal materials, the cleaning liquid 50 needs to be changed according to the type of metal material used, which may cause the cleaning equipment to be corroded. Always check for damage.

The present invention has been made to solve the above problems, and provides a mask for forming a thin film and a cleaning method thereof that can remove the foreign matter deposited on the mask using a lift off method without damaging the mask. , Its purpose is.

Mask for forming a thin film for achieving the above object, the mask pattern having a blocking portion and an opening; It is attached on the mask pattern, and includes a film having alkali solubility.

The mask pattern is formed of one of iron, nickel, chromium or an alloy thereof.

The thickness of the film is 10 μm to 15 μm.

In addition, the cleaning method for a thin film forming mask for achieving the same object, the step of dipping a mask for forming a thin film comprising a mask pattern having a blocking portion and an opening and a film attached on the mask pattern and having an alkali solubility in a cleaning liquid. ; Dissolving the film in the cleaning solution to lift off the foreign matter deposited on the film.

The cleaning liquid is an alkaline solution.

In the step in which the foreign matter is lifted off, the foreign matter deposited on the film is separated while the film is dissolved in the cleaning liquid.

The thin film forming mask and cleaning method thereof according to the present invention as described above have the following effects.

First, since the foreign matter deposited on the mask is removed by using a lift off method, the mask may be cleaned without damaging the mask pattern. Specifically, the foreign matter deposited on the film can be removed from the mask by removing the film attached on the mask pattern using the cleaning liquid. Therefore, since the mask is cleaned using a cleaning liquid which can remove only the film, the mask can be cleaned without damaging the mask.

Second, there is no need to change the cleaning liquid according to the foreign material deposited on the mask, and the organic light emitting display device may be manufactured using various kinds of metal materials or organic materials.

1 is a cross-sectional view of a general organic light emitting display device.
2 is a cross-sectional view showing a method of cleaning a mask for forming a thin film in general.
3A is a perspective view of a mask for forming a thin film of the present invention.
3B is a cross-sectional view of the mask for forming a thin film of the present invention.
4 is a cross-sectional view of forming a thin film on a substrate using the thin film forming mask of the present invention.
5A and 5B are sectional views showing a cleaning method of a thin film forming mask of the present invention.
6a to 6c are photographs showing the degree of cleaning of the mask according to the thickness of the film.

In general, a thin film forming mask of an organic light emitting diode display has an opening and a blocking portion to form an organic light emitting layer or a cathode by depositing an organic material or a metal material on a substrate through the opening. However, the organic material or the metal material is not only deposited on the substrate exposed through the opening, but is also deposited on the front surface of the mask and foreign matter deposited on the mask impairs the accuracy of the mask. Therefore, after a certain number of processes, the mask should be cleaned to remove foreign substances such as organic materials or metal materials.

In the present invention, a foreign matter is deposited on the film other than the mask pattern by attaching the film on the mask pattern, and the foreign matter deposited on the film is removed from the mask by dissolving the film in the cleaning solution using the alkaline solution as the cleaning solution. Accordingly, the present invention relates to a mask for forming a thin film and a method for cleaning the mask, which can clean the mask without damaging the mask, and can clean the mask on which various kinds of metals or organic materials are deposited without changing the cleaning liquid or the cleaning apparatus. .

Hereinafter, a thin film forming mask and a cleaning method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

3A is a perspective view of a thin film forming mask of the present invention, and FIG. 3B is a cross-sectional view of the thin film forming mask of the present invention. 4 is a cross-sectional view of forming a thin film on a substrate using the thin film forming mask of the present invention.

As shown in FIG. 3A, the thin film forming mask 300 of the present invention includes a mask pattern 300a and a film 300b attached to the mask pattern 300a. The mask pattern 300a has an opening 300c so that an organic material or a metal material is deposited on the substrate through the opening 300c, and the film 300b also exposes the opening 300c of the mask pattern 300a. It is attached on the mask pattern 300a except the opening 300c. The mask pattern 300a is made of a metal material, and is preferably formed of one of iron (Fe), nickel (Ni), and chromium (Cr) or an alloy thereof.

Generally, when the metal material or the organic material is deposited through the opening 300c of the thin film forming mask 300, the metal material or the organic material is also deposited on the thin film forming mask 300. Therefore, after a predetermined number of times, the thin film forming mask 300 should be cleaned to remove foreign substances deposited on the thin film forming mask 300.

As described above, in general, a method for cleaning a thin film forming mask includes dipping a thin film forming mask in which a foreign material is deposited in a cleaning tank containing a cleaning liquid to remove only foreign matter. In this case, the foreign matter and the mask may be removed together. Therefore, a cleaning liquid that does not damage the mask should be used. Moreover, in recent years, since the negative electrode is formed of various metal materials, the cleaning liquid has to be changed according to the type of metal material used. As a result, it is difficult to corrode the cleaning equipment or selectively remove only the metal material during cleaning.

Therefore, in order to solve the above-mentioned problem, the mask for forming a thin film of the present invention attaches the film 300b on the mask pattern 300a. In particular, the film 300b is preferably a film 300b having alkali solubility so as to be removed by a cleaning liquid in a mask cleaning process to be described later.

As shown in FIG. 4, an organic material or a metal material is deposited on the substrate 700 using the thin film forming mask 300 to form a thin film 800. Specifically, one side of the mask pattern 300a to which the film 300b is not attached corresponds to the substrate 700, and the other side of the mask pattern 300a to which the film 300b is attached is a metal material or an organic material source. Corresponds to (Source) 900. Therefore, the metal material or the organic material deposited on the substrate 700 through the opening 300c is deposited not only on the substrate 700 but also on the mask 300 for forming a thin film, specifically, on the film 300b and thus the mask 300. ), The thin film pattern defect may occur.

That is, the thin film forming mask 300 of the present invention attaches the film 300b on the mask pattern 300a in order to prevent the foreign matter 400 from being directly deposited on the mask pattern 300a. Allow the foreign material 400 to be deposited on. Therefore, the thin film formation mask 300 may be cleaned by removing only the film 300b on which the foreign matter 400 is deposited.

At this time, if the thickness of the film 300b is too thin, the foreign matter 400 may not be completely removed even if the film 300b is removed, and if the thickness of the film 300b is too thick, the lift-off will not occur. . Therefore, it is preferable that the thickness of the film 300b is 10 micrometers-15 micrometers, and the cleaning degree related to the thickness of the film 300b is demonstrated concretely in the washing | cleaning method of the mask for thin film formation mentioned later.

Hereinafter, the cleaning method of the mask for forming a thin film of the present invention will be described in detail.

5A and 5B are cross-sectional views illustrating a cleaning method of a thin film forming mask of the present invention, and FIGS. 6A to 6C are photographs showing the degree of cleaning of the mask according to the thickness of the film.

As illustrated in FIG. 5A, a thin film forming mask 300 including a mask pattern 300a and a film 300b attached on the mask pattern 300a is dipped into a cleaning tank 600 containing a cleaning liquid 500. )do. The foreign material 400 such as an organic material or a metal material is deposited on the film 300b.

As illustrated in FIG. 5B, the foreign matter 400 deposited on the film 300b is removed using a lift off method. Specifically, since the film 300b has alkali solubility, only the film 300b is dissolved in the cleaning liquid 500 using the alkaline solution as the cleaning liquid 500. That is, the mask pattern 300a and the foreign matter 400 do not have any solubility with respect to the cleaning liquid 500.

As the film 300b is dissolved in the cleaning liquid 500, the foreign matter 400 deposited on the film 300b may be separated from the mask 300 for forming a thin film, thereby cleaning the mask 300 for forming a thin film.

In general, since the mask pattern 300b is formed of a metal material, when the foreign material 400 is a metal material, the cleaning liquid 500 may remove both the foreign material 400 and the mask pattern 300a. However, in the method for cleaning the thin film forming mask 300 according to the present invention, even if the mask pattern 300a is formed of a metal material, the foreign matter 400 is not directly removed, but is attached to the mask pattern 300a. Since the film 300b is dissolved in the cleaning liquid 500 and the foreign matter 400 is removed, the film 300b is not damaged.

In addition, even if the material to be deposited is changed, it is not necessary to change the cleaning liquid 500 or the cleaning apparatus according to the type of material, and only the film 300b may be removed to clean the mask 300 for forming a thin film.

In particular, the degree of cleaning of the thin film forming mask 300 varies depending on the thickness of the film 300b. 6A, when the film 300b has a thickness of 3 μm, the foreign matter 400 remains even when the film 300b is removed. As shown in FIG. 6B, the same applies to the case where the film 300b has a thickness of 8 μm. . That is, if the thickness of the film 300b is too thin as described above, even if the film 300b is removed, the foreign material 400 such as a metal material or an organic material may remain on the surface of the thin film forming mask 300.

 However, as shown in FIG. 6C, when the film 300b has a thickness of 10 μm, the foreign matter 400 is removed cleanly. In addition, if the thickness of the film 300b is too thick, it takes too much time for the film 300b to dissolve in the cleaning liquid 500, so that the lift-off may not be completed in a short time. Therefore, it is preferable that the thickness of the film 300b is 10 micrometers-15 micrometers.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

300: thin film forming mask 300a: mask pattern
300b: film 300c: opening
400: foreign matter 500: cleaning liquid
600: cleaning tank 700: substrate
800: thin film 900: source

Claims (6)

A mask pattern having a blocking portion and an opening;
And a film having alkali solubility attached to the mask pattern. The method of claim 1,
The mask pattern is a mask for forming a thin film, characterized in that formed of one or an alloy of iron, nickel, chromium. The method of claim 1,
The thickness of the film is a thin film forming mask, characterized in that 10㎛ to 15㎛. Dipping a mask for forming a thin film including a mask pattern having a blocking portion and an opening, and a film attached on the mask pattern and having an alkali solubility in a cleaning liquid;
And dissolving the film in the cleaning liquid so that the foreign matter deposited on the film is lifted off. The method of claim 4, wherein
The said cleaning liquid is an alkaline solution, The cleaning method of the mask for thin film formation characterized by the above-mentioned. The method of claim 4, wherein
Lifting off the foreign matter (Lift Off), the cleaning method of the mask for forming a thin film, characterized in that the foreign matter deposited on the film is separated as the film is dissolved in the cleaning liquid.

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