KR20230175135A - Manufacturing method of metal mask for organic light emitting diode deposition with improved cell end sharpness by two-step processing - Google Patents

Abstract

A metal for OLED deposition that improves the sharpness of the cell ends through two-step processing that can minimize process defects due to damage to the substrate by selectively removing the sharp parts of the ends of the cells produced by two-step processing through laser processing to form a berm. Disclosed is a mask and its manufacturing method.

Description

Method for manufacturing metal mask for OLED deposition with improved sharpness of cell ends through two-step processing {MANUFACTURING METHOD OF METAL MASK FOR ORGANIC LIGHT EMITTING DIODE DEPOSITION WITH IMPROVED CELL END SHARPNESS BY TWO-STEP PROCESSING}

The present invention relates to a metal mask for OLED deposition that improves the sharpness of the cell ends by two-step processing and a manufacturing method thereof. More specifically, only the sharp parts of the cell ends produced by two-step processing are selectively removed through laser processing. It relates to a metal mask for OLED deposition that improves the sharpness of the cell ends through two-step processing that can minimize process defects due to substrate damage by forming a berm and a method of manufacturing the same.

In general, display devices are used and applied to various devices. These display devices are applied not only to small devices such as smartphones and tablet PCs, but also to large devices such as TVs, monitors, and public displays (PDs).

Recently, demand for ultra-high resolution (UHD) of 500 PPI (Pixel Per Inch) or higher is increasing, and high-resolution display devices are being applied to small and large devices. Accordingly, interest in technologies for low-power and high-resolution implementation is increasing.

Commonly used display devices can be largely divided into LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode) depending on the driving method. LCD is a display device driven using liquid crystal. It has a structure in which a light source including a CCFL (Cold Cathode Fluorescent Lamp) or LED (Light Emitting Diode) is placed at the bottom of the liquid crystal, and the liquid crystal is placed on the light source. It is a display device that is driven by controlling the amount of light emitted from the light source.

On the other hand, OLED is a display device driven using organic materials. It does not require a separate light source, and the organic material itself acts as a light source and can be driven with low power. In addition, OLED can express infinite contrast ratio, has a response speed about 1,000 times faster than LCD, and has an excellent viewing angle, so it is attracting attention as a display device that can replace LCD.

In particular, in an OLED display device, the organic material contained in the emitting layer can be deposited on the substrate by a metal mask for OLED deposition called a fine metal mask (FMM), and the deposited organic material is formed on the metal mask for OLED deposition. It is formed in a pattern corresponding to the mask pattern hole and can function as a pixel.

Additionally, the metal mask for OLED deposition may be made of a metal plate made of Invar alloy material containing iron (Fe) and nickel (Ni). At this time, mask pattern holes are formed on one side and the other side of the metal mask for OLED deposition, and the mask pattern holes may be formed at positions corresponding to the pixel patterns. Accordingly, organic materials such as red, green, and blue can pass through the mask pattern hole of the metal plate and be deposited on the substrate, and a pixel pattern can be formed on the substrate.

This metal mask for OLED deposition forms a mask pattern hole through upper etching and lower etching. During the process of forming the mask pattern hole, a sharp dummy pattern is formed at the cell end of the cross section of the mask sheet, which can scratch the substrate during organic material deposition. There was a problem that caused damage to the back.

Related prior literature includes Korean Patent Publication No. 10-1866382 (announced on June 12, 2018), which describes a fine metal mask for manufacturing organic light-emitting diode panels.

The purpose of the present invention is to improve the sharpness of the cell ends by two-step processing, which can minimize process defects due to damage to the substrate by selectively removing only the sharp parts of the ends of the cells produced by two-step processing through laser processing to form a berm. To provide a metal mask for OLED deposition and a method for manufacturing the same.

In order to achieve the above object, the method of manufacturing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to an embodiment of the present invention is (a) a mask cell area and a dummy disposed outside the mask cell area. Forming a first mask pattern and a second mask pattern on the upper and lower surfaces of a mask sheet having a region; (b) forming a first etching groove having a tapered cross-section whose thickness increases from the top to the bottom of the mask sheet on the upper surface of the mask sheet by primary etching using the first and second mask patterns; (c) removing the first and second mask patterns from the mask sheet on which the first etching groove is formed, and then forming a third mask pattern and a fourth mask pattern on the exposed upper and lower surfaces of the mask sheet; (d) removing a portion of the upper and lower surfaces of the mask sheet through secondary etching using the third and fourth mask patterns, and having a tapered cross-section whose thickness increases from the lower surface to the upper surface of the mask sheet. After forming grooves and mask pattern holes, removing the third and fourth mask patterns; and (e) removing part of the cell end portions of the mask sheet located on both opposing sides of the mask pattern hole through laser processing to form a bluntly cut laser processing surface. A method of manufacturing a metal mask for OLED deposition comprising a. , In step (e), the laser processing uses an ultrashort pulse laser, which is a femto sencond or pico second pulse laser, and in step (e), the laser processing surface is subjected to two-step processing. It is provided by forming a berm by selectively removing only the sharp portion of the cell end produced by laser processing, and the laser processing surface is located at the cell end portion of the mask sheet located at both ends facing the mask pattern hole. By being positioned at the inner end of the first etching groove disposed on the upper surface of the mask sheet, even if sagging occurs due to the load of the metal mask for OLED deposition during the process of depositing organic materials on the glass substrate, the glass Damage to the substrate is prevented, and in step (e), the laser processing surface is formed to be inclined at an angle of 50 to 80° with respect to the upper surface of the mask sheet by performing laser processing at an oblique angle. It is characterized by

The step (e) includes (e-1) aligning the laser processing device to an upper portion spaced apart from the cell end portions of the mask sheet located on both opposing sides of the mask pattern hole; (e-2) laser processing by locally irradiating only cell end portions of the mask sheet with a laser beam from the laser processing device; and (e-3) removing a portion of the cell end portion of the mask sheet through the laser processing to form a bluntly cut laser processing surface.

The metal mask for OLED deposition, which improves the sharpness of the cell ends by two-step processing according to the present invention, and its manufacturing method are based on forming a berm by selectively removing only the sharp parts of the cell ends produced by two-step processing through laser processing. This provides a laser processing surface.

Accordingly, the metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the present invention and its manufacturing method are used to reduce the risk of damage due to the load of the metal mask for OLED deposition when performing the process of depositing organic materials on the substrate. Even if the end of the cell bends in the direction of the glass substrate due to sagging, a laser-processed surface with a smooth berm formed by laser processing is located at the end of the cell of the mask sheet.

As a result, the metal mask for OLED deposition, which has improved the sharpness of the cell ends by two-step processing according to the first embodiment of the present invention, has a smooth laser processing surface located at the cell ends of the mask sheet, so it is a glass substrate. It is possible to minimize damage such as scratches, which ultimately has the effect of improving process yield.

Figure 1 is a cross-sectional view showing a general metal mask for OLED deposition.
Figure 2 is an enlarged cross-sectional view of part A of Figure 1.
Figure 3 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention.
Figure 4 is an enlarged cross-sectional view of part B of Figure 3.
Figure 5 is a schematic diagram illustrating the process of laser processing a metal mask for OLED deposition according to the first embodiment of the present invention.
Figure 6 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the second embodiment of the present invention.
Figure 7 is a schematic diagram illustrating the process of laser processing a metal mask for OLED deposition according to a third embodiment of the present invention.
Figure 8 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the third embodiment of the present invention.
Figure 9 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the fourth embodiment of the present invention.
Figure 10 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the fifth embodiment of the present invention.
Figures 11 to 17 are cross-sectional process views showing a method of manufacturing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is provided. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, with reference to the attached drawings, a detailed description will be given of a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to a preferred embodiment of the present invention and a method of manufacturing the same.

Figure 1 is a cross-sectional view showing a general metal mask for OLED deposition, and Figure 2 is a cross-sectional view showing an enlarged portion A of Figure 1.

As shown in FIGS. 1 and 2, a general metal mask 1 for OLED deposition includes a mask sheet 20, a first etching groove 40, and a second etching groove 60.

At this time, the mask sheet 20 has an upper surface 20a and a lower surface 20b opposite to the upper surface 20a. This mask sheet 20 has a mask cell area MA in which at least one mask pattern hole 25 is disposed, and a dummy area DA disposed outside the mask cell area MA.

The first etching groove 40 is disposed on the upper surface 20a of the mask sheet 20 and is disposed at a position corresponding to the mask pattern hole 25. In addition, the second etching groove 60 is disposed on the lower surface 20b of the mask sheet 20 and is disposed at a position corresponding to the mask pattern hole 25. Accordingly, the mask pattern hole 25 is disposed at a position overlapping the first etching groove 40 and the second etching groove 60 to penetrate the upper surface 20a and the lower surface 20b of the mask sheet 20. is formed

The general metal mask 1 for OLED deposition having the above-described configuration is formed by first etching the upper surface 20a of the mask sheet 20 to form the first etching groove 40, and the lower surface of the mask sheet 20 ( It is formed by two-step processing in which 20b) is secondarily etched to form the second etching groove 60. At this time, the mask pattern hole 25 is disposed at a position overlapping with the first etching groove 40 and the second etching groove 60 and is formed to penetrate the upper surface 20a and the lower surface 20b of the mask sheet 20. do.

However, the metal mask 1 for general OLED deposition is unavoidable during the process of forming the first etching groove 40 and the second etching groove 60 by wet etching to form the mask pattern hole 25 through two-step processing. The cell end portions (T) on both opposing sides of the cross section of the mask sheet 20 are sharply formed in the shape of a blade. During the organic material deposition process, the sharp cell end portion (T) of the mask sheet 20 is bent in the direction of the glass substrate (not shown) in close contact with the OLED deposition metal mask 1, causing scratches, etc. on the glass substrate. It causes damage, which ultimately acts as a problem that reduces process yield.

To solve this problem, the metal mask for OLED deposition, which improves the sharpness of the cell ends by two-step processing according to an embodiment of the present invention, selectively removes only the sharp parts of the cell ends produced by two-step processing through laser processing to create a berm. It is possible to minimize process defects due to damage to the substrate.

This will be described in more detail with reference to the attached drawings below.

Figure 3 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention, and Figure 4 is an enlarged cross-sectional view showing part B of Figure 3.

Referring to Figures 3 and 4, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention includes a mask sheet 120 and a first etching groove 140. ), a second etching groove 160, and a laser processing surface (L).

The mask sheet 120 has an upper surface 120a and a lower surface 120b opposite to the upper surface 120a. This mask sheet 120 has a mask cell area (MA) in which at least one mask pattern hole 125 penetrating the upper surface 120a and the lower surface 120b is disposed, and a mask cell area (MA) disposed outside the mask cell area (MA). It has a dummy area (DA).

At this time, the mask sheet 120 may be made of materials such as SUS 300 series, SUS 400 series, Invar, Ni alloy, etc., which prevents deformation of the metal mask 100 in the high temperature environment of the organic material deposition process. This is because there is an effect that can be minimized.

The mask pattern hole 125 is disposed in the mask cell area MA and penetrates the upper surface 120a and the lower surface 120b of the mask sheet 120. That is, the mask pattern holes 125 may be arranged to penetrate the upper surface 120a and lower surface 120b of the mask sheet 120 for each cell. In addition, the mask pattern hole 125 may be arranged to penetrate only a portion of the upper surface 120a and lower surface 120b of the mask sheet 120 for each cell.

The first etching groove 140 is disposed on the upper surface 120a of the mask sheet 120 and is disposed at a position corresponding to the mask pattern hole 125. Here, the first etching groove 140 has a first thickness and a first width. This first etching groove 140 may be formed by wet etching. Accordingly, the first etching groove 140 may have a tapered cross section whose thickness increases in the direction from the upper surface 120a to the lower surface 120b of the mask sheet 120.

The second etching groove 160 is disposed on the lower surface 120b of the mask sheet 120 and is disposed at a position corresponding to the mask pattern hole 125. Here, the second etching groove 160 may have a second thickness that is thicker than the first thickness and a second width that is narrower than the first width, but is not limited thereto. Like the first etching groove 140, the second etching groove 160 may be formed by wet etching. Accordingly, the second etching groove 160 may have a tapered cross section whose thickness increases in the direction from the lower surface 120b of the mask sheet 120 to the upper surface 120a.

In this way, the first etching groove 140 is disposed on the upper surface 120a of the mask sheet 120 and is disposed at a position corresponding to the mask pattern hole 125. In addition, the second etching groove 160 is disposed on the lower surface 120b of the mask sheet 120 and is disposed at a position corresponding to the mask pattern hole 125. Accordingly, the mask pattern hole 125 is disposed at a position overlapping the first etching groove 140 and the second etching groove 160 to penetrate the upper surface 120a and the lower surface 120b of the mask sheet 120. is formed

The laser processing surface (L) is located at the cell end portion (T) of the mask sheet 120 located on both sides facing the mask pattern hole 125. This laser processing surface (L) is formed by bluntly cutting the cell end portion (T) of the mask sheet 120 by partially removing it through laser processing.

That is, the laser processing surface (L) is formed by physically removing a portion of the sharp portion (T) at the cell end of the mask sheet 120 through laser processing. Here, the laser processing surface L is formed along a vertical direction that intersects the upper surface 120a of the mask sheet 120. Accordingly, the laser processing surface L has a smooth cross section cut along the vertical direction intersecting the upper surface 120a of the mask sheet 120 by laser processing.

As such, in the present invention, only the sharp portions (T) of the cell ends of the mask sheet 120 manufactured by two-step processing are selectively removed through laser processing to form a berm.

Accordingly, the metal mask 100 for OLED deposition, which has improved the sharpness of the cell end by two-step processing according to an embodiment of the present invention, is used when performing a process for depositing organic materials on a substrate. Even if the cell end portion (T) is bent in the direction of the glass substrate due to deflection due to the load of ), the cell end (T) of the mask sheet 120 has a smooth berm formed on the laser processing surface (L). This is located.

As a result, the metal mask 100 for OLED deposition, which has improved the sharpness of the cell ends by two-step processing according to an embodiment of the present invention, has a smooth laser processing surface (L) at the cell end portion of the mask sheet 120 ( Since it is located at T), it is possible to minimize damage such as scratches to the glass substrate, which ultimately has the effect of improving process yield.

Meanwhile, Figure 5 is a schematic diagram for explaining the process of laser processing a metal mask for OLED deposition according to the first embodiment of the present invention, and will be described in more detail in connection with Figures 3 and 4.

As shown in FIGS. 3 to 5, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention is a mask sheet 120 manufactured by two-step processing. In order to selectively laser process only the sharp portion (T) of the cell end of the mask sheet 120, the laser processing device 200 is aligned on the upper part spaced apart from the cell end portion (T) of the mask sheet 120.

At this time, the laser processing device 200 includes a laser generating unit 210, an optical unit 220 that processes the laser beam LB generated by the laser generating unit 210, and a laser processed by the optical unit 220. A reflector 230 for reflecting the beam LB in the direction of the mask sheet 120, and a laser beam LB reflected by the reflector 230 are focused to the cell end portion T of the mask sheet 120. It includes a focusing lens 240 for irradiation.

The laser generation unit 210 generates an ultrashort pulse laser, which may include a femto second or pico second laser. In this way, when laser processing is performed using an ultrashort pulse laser, it is possible to precisely cut the mask sheet 120 made of metal in a short time.

The optical unit 220 may include a half-wave plate, a polarizer, etc. for processing the laser beam LB generated by the laser generation unit 210. The optical unit 220 includes various optical systems and can change the laser beam LB in various ways depending on processing conditions.

A CCD camera 250 may be installed in the upper part spaced apart from the reflector 230. This CCD camera 250 captures the processing status of the mask sheet 120 in real time.

The focusing lens 240 serves to focus the laser beam LB changed by the reflector 230 on the mask sheet 120.

As such, in the present invention, after aligning the laser processing device 200 to the upper part spaced apart from the cell end portion (T) of the mask sheet 120 located on both opposing sides of the mask pattern hole 125, the laser processing device Laser processing is performed by locally irradiating the laser beam LB generated from 200 only to the cell end portion T of the mask sheet 120. Thereafter, only the sharp portions (T) of the cell ends of the mask sheet 120 are partially removed through laser processing to form a dull cut laser processing surface (L).

Here, the laser processing surface L may be formed along a vertical direction intersecting the upper surface 120a of the mask sheet 120.

For this purpose, the focusing lens 240 of the laser processing device 200 is preferably mounted to vertically cross the upper part spaced apart from the mask sheet 120, which means that the laser beam LB focused by the focusing lens 240 This is to irradiate in a direction perpendicular to the cell end portion (T) of the mask sheet 120. As a result, the laser processing surface L has a smooth cross section cut along the vertical direction intersecting the upper surface 120a of the mask sheet 120 by laser processing.

The metal mask for OLED deposition, which improves the sharpness of the cell ends by two-step processing according to the first embodiment of the present invention described above, creates a berm by selectively removing only the sharp parts of the cell ends produced by two-step processing through laser processing. By forming, a laser processing surface is provided.

Accordingly, the metal mask for OLED deposition, which has improved the sharpness of the cell ends by two-step processing according to the first embodiment of the present invention, is sensitive to the load of the metal mask for OLED deposition when performing the process of depositing organic materials on the substrate. Even if the end of the cell is bent in the direction of the glass substrate due to sagging, a laser-processed surface with a smooth berm formed by laser processing is located at the end of the cell of the mask sheet.

As a result, the metal mask for OLED deposition, which has improved the sharpness of the cell ends by two-step processing according to the first embodiment of the present invention, has a smooth laser processing surface located at the cell ends of the mask sheet, so it is a glass substrate. It is possible to minimize damage such as scratches, which ultimately has the effect of improving process yield.

Meanwhile, Figure 6 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the second embodiment of the present invention, and Figure 7 is a metal mask for OLED deposition according to the third embodiment of the present invention. This is a schematic diagram to explain the process of laser processing a metal mask.

As shown in FIGS. 6 and 7, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the second embodiment of the present invention is described with reference to FIGS. 3 and 4. The only difference between the metal mask for OLED deposition according to the first embodiment is the shape of the laser processing surface (L), and other components are substantially the same, so redundant description will be omitted and the description will focus on the differences.

That is, the laser processing surface L according to the second embodiment of the present invention does not perform laser processing in a vertical direction with respect to the upper surface 120a of the mask sheet 120, but at an oblique angle inclined at a certain angle. It is formed by performing processing.

This oblique angle laser processing may have lower processing precision than vertical laser processing, but has the advantage of being able to process the sharp portion (T) of the cell end of the mask sheet 120 to be more blunt.

For this purpose, the focusing lens 240 of the laser processing device 200 is preferably mounted at a certain angle on the upper part of the mask sheet 120, which is the laser beam focused by the focusing lens 240. This is to irradiate (LB) to the cell end portion (T) of the mask sheet 120 at an oblique angle.

As a result, in the second embodiment of the present invention, it is possible to process the sharp part (T) of the cell end of the mask sheet 120 more bluntly by performing laser processing at an oblique angle, so that the laser processing surface (L ) can be formed more smoothly.

For this purpose, the laser processing surface L is preferably formed to be inclined at an angle of 50 to 80 degrees with respect to the upper surface 120a of the mask sheet 120. If the laser processing surface (L) has an angle of less than 50° or more than 80° with respect to the upper surface (120a) of the mask sheet 120, the advantage of performing laser processing at an oblique angle may be lost. Therefore, it is not desirable.

Figure 8 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the third embodiment of the present invention.

As shown in FIG. 8, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the third embodiment of the present invention is the first embodiment described with reference to FIGS. 3 and 4. The only difference between the metal mask for OLED deposition according to the example is the shape of the laser processing surface (L), and other components are substantially the same, so redundant explanation will be omitted and the explanation will focus on the differences.

That is, the laser processing surface (L) according to the third embodiment of the present invention is formed in a step structure.

In this way, when the laser processing surface (L) is formed in a step structure, it becomes possible to control the sharp part (T) of the cell end of the mask sheet 120 to be more blunt due to the step difference in the step surface. .

Here, the laser processing surface (L) according to the third embodiment of the present invention includes a diagonal portion formed to have a constant inclination with respect to the upper surface (120a) of the mask sheet 120, an upper surface (120a) of the mask sheet 120, and It has a horizontal portion formed along a parallel horizontal direction and a vertical portion formed along a vertical direction intersecting the upper surface 120a of the mask sheet 120. Here, the laser processing surface L according to the third embodiment of the present invention can be formed by performing vertical laser processing and oblique angle laser processing in parallel.

Although not shown in the drawing, the laser processing surface (L) according to the third embodiment of the present invention has a diagonal portion formed to have a constant inclination with respect to the upper surface (120a) of the mask sheet 120 and the upper surface of the mask sheet 120 ( It may have only a vertical portion formed along a vertical direction intersecting 120a).

Figure 9 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the fourth embodiment of the present invention.

As shown in FIG. 9, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the fourth embodiment of the present invention includes a mask sheet 120 and a first etching groove 140. , It shows a structural difference from the first embodiment of the present invention in that it further includes a half pattern 180 in addition to the second etching groove 160 and the laser processing surface (L).

That is, in the fourth embodiment of the present invention, the half pattern 180 is used to form the first etching groove 140 by primarily processing the upper surface 120a of the mask sheet 120. It is formed by processing the lower surface (120b) of ) together. Accordingly, the half pattern 180 can be formed simultaneously with the first etching groove 140 without applying an additional process. Accordingly, the half pattern 180 has a third thickness that is the same or similar to the first thickness, which is the thickness of the first etching groove 140.

This half pattern 180 is formed to be disposed and integrally connected to the entire mask cell area MA of the lower surface 120b of the mask sheet 120, excluding the second etching groove 160.

In this way, when the half pattern 180 is formed on the lower surface 120b of the mask sheet 120, the stress concentrated on the cell end portion T of the mask sheet 120 is transferred to the lower surface 120b of the mask sheet 120. ) It is possible to offset stress by dispersing it to the edges. As a result, it is possible to alleviate the bending of the cell ends caused by two-step processing.

Figure 10 is a cross-sectional view showing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the fifth embodiment of the present invention.

As shown in FIG. 10, the metal mask 100 for OLED deposition with improved sharpness of the cell end by two-step processing according to the fifth embodiment of the present invention includes a mask sheet 120 and a first etching groove 140. , It shows a structural difference from the first embodiment of the present invention in that it further includes a half pattern 180 in addition to the second etching groove 160 and the laser processing surface (L).

That is, in the fifth embodiment of the present invention, a plurality of half patterns 180 are formed in the mask cell area MA of the lower surface 120b of the mask sheet 120 to be spaced apart from each other at equal intervals. In this way, when the plurality of half patterns 180 are arranged at equal intervals in the mask cell area (MA) of the lower surface 120b of the mask sheet 120, the cell end portions (T) of the mask sheet 120 The concentrated stress can be distributed to the edge of the lower surface 120b of the mask sheet 120 through the plurality of half patterns 180 to offset the stress. As a result, it is possible to alleviate the bending of the cell ends caused by two-step processing.

Hereinafter, a method of manufacturing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention will be described with reference to the attached drawings.

Figures 11 to 17 are cross-sectional process views showing a method of manufacturing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing according to the first embodiment of the present invention.

As shown in FIG. 11, on the upper surface 120a and lower surface 120b of the mask sheet 120 having a mask cell area MA and a dummy area DA disposed outside the mask cell area MA. A first mask pattern (M1) and a second mask pattern (M2) are formed.

Here, the first mask pattern M1 is formed to cover the entire portion of the upper surface 120a of the mask sheet 120 except for the central portion of the mask cell area MA. In addition, the second mask pattern M2 is formed to cover the entire lower surface 120b of the mask sheet 120.

These first and second mask patterns M1 and M2 are formed by selectively exposing and developing the first and second mask layers formed to cover the entire upper surface 120a and lower surface 120b of the mask sheet 120. It can be formed by carrying out.

Next, as shown in FIG. 12, a first etching groove 140 is formed on the upper surface 120a of the mask sheet 120 through primary etching using the first and second mask patterns M1 and M2. .

In this step, wet etching or dry etching may be used for the first etching. Among these, it is more preferable to use wet etching.

Here, the first etching groove 140 has a first thickness and a first width. The first etching groove 140 may have a tapered cross section whose thickness increases from the upper surface 120a to the lower surface 120b of the mask sheet 120.

Next, as shown in FIG. 13, the first and second mask patterns (M1 and M2 in FIG. 12) are removed from the mask sheet 120 on which the first etching groove 140 is formed.

Here, the first and second mask patterns may be removed by a strip process of spraying a strip liquid.

14 and 15, a third mask pattern M3 and a fourth mask are formed on the upper surface 120a and lower surface 120b of the mask sheet 120 exposed by removal of the first and second mask patterns. Form a pattern (M4).

Here, the third and fourth mask patterns M3 and M4 are formed to cover the entire upper surface 120a and lower surface 120b of the mask sheet 120 through a selective exposure and development process. It can be formed by carrying out . At this time, the third mask pattern M3 is formed to expose only a portion of the first etching groove 140, and the fourth mask pattern M4 is formed to expose the second etching groove formation area.

Next, part of the upper surface 120a and lower surface 120b of the mask sheet 120 are removed through secondary etching using the third and fourth mask patterns M3 and M4, and the second etching groove 160 and the mask are formed. A pattern hole 125 is formed.

In this step, wet etching or dry etching may be used for the secondary etching. Among these, it is more preferable to use wet etching.

Here, the second etching groove 160 may have a second thickness that is thicker than the first thickness and a second width that is narrower than the first width, but is not limited thereto. This second etching groove 160 may have a tapered cross section whose thickness increases in the direction from the lower surface 120b of the mask sheet 120 to the upper surface 120a.

Next, the third and fourth mask patterns M3 and M4 are removed from the mask sheet 120 on which the second etching groove 160 and the mask pattern hole 125 are formed.

Here, the third and fourth mask patterns M3 and M4 may be removed through a strip process of spraying a strip liquid.

As shown in FIGS. 16 and 17, the mask sheet 120 is located on both opposing sides of the mask pattern hole 125 exposed to the outside by removal of the third and fourth mask patterns (M3 and M4 in FIG. 15). ) of the cell end portion (T) is partially removed through laser processing to form a bluntly cut laser processing surface (L).

The step of forming the laser processing surface (L) will be described in more detail as follows.

First, the laser processing device 200 is aligned to the upper part spaced apart from the cell end portion (T) of the mask sheet 120 located on both opposing sides of the mask pattern hole 125.

Here, as shown in FIG. 6, the laser processing device 200 includes a laser generation unit 210, an optical unit 220 for processing the laser beam LB generated from the laser generation unit 210, and an optical unit ( A reflector 230 for reflecting the laser beam LB processed in 220 in the direction of the mask sheet 120, and a cell of the mask sheet 120 by focusing the laser beam LB reflected by the reflector 230. It includes a focusing lens 240 for irradiating to the end portion (T).

Next, laser processing is performed by locally irradiating only the cell end portions T of the mask sheet 120 with the laser beam LB from the laser processing device 20.

Here, for laser processing, an ultrashort pulse laser, which is a femto second or pico second pulse laser, is used. In this way, when laser processing is performed using an ultrashort pulse laser, it is possible to precisely cut the mask sheet 120 made of metal in a short time.

Next, a portion of the cell end portion (T) of the mask sheet 120 is removed through laser processing to form a bluntly cut laser processing surface (L).

Here, the laser processing surface L may be formed along a vertical direction intersecting the upper surface 120a of the mask sheet 120.

For this purpose, the focusing lens 240 of the laser processing device 200 is preferably mounted vertically on the upper part spaced apart from the mask sheet 120, which directs the laser beam LB focused by the focusing lens 240. This is to irradiate in a direction perpendicular to the cell end portion (T) of the mask sheet 120. As a result, the laser processing surface L has a smooth cross section cut along the vertical direction intersecting the upper surface 120a of the mask sheet 120 by laser processing.

Additionally, the laser processing surface L may be formed to be inclined at an angle of 50 to 80 degrees with respect to the upper surface 120a of the mask sheet 120.

In addition, the laser processing surface (L) includes an oblique portion formed to have a constant inclination with respect to the upper surface 120a of the mask sheet 120, and a horizontal portion formed along a horizontal direction parallel to the upper surface 120a of the mask sheet 120. It may also be formed as a step structure with a vertical portion formed along a vertical direction intersecting the upper surface 120a of the mask sheet 120.

With the above, the method of manufacturing a metal mask for OLED deposition that improves the sharpness of the cell end by two-step processing according to an embodiment of the present invention can be completed.

The method of manufacturing a metal mask for OLED deposition, which improves the sharpness of the cell end by two-step processing according to the first embodiment of the present invention described above, selectively removes only the sharp portion of the cell end produced by two-step processing through laser processing. By forming a berm, a laser processing surface is provided.

Accordingly, the method of manufacturing a metal mask for OLED deposition that improves the sharpness of the cell end by two-step processing according to the first embodiment of the present invention is a method of manufacturing a metal mask for OLED deposition when performing a process of depositing an organic material on a substrate. Even if the end of the cell bends in the direction of the glass substrate due to deflection due to load, a laser processed surface with a smooth berm formed by laser processing is located at the end of the cell of the mask sheet.

As a result, the method of manufacturing a metal mask for OLED deposition that improves the sharpness of the cell end by two-step processing according to the first embodiment of the present invention has a smooth laser processing surface located at the cell end of the mask sheet, so the glass material Damage such as scratches to the substrate can be minimized, which ultimately has the effect of improving process yield.

Although the above description focuses on the embodiments of the present invention, various changes or modifications can be made at the level of a person skilled in the art in the technical field to which the present invention pertains. These changes and modifications can be said to belong to the present invention as long as they do not depart from the scope of the technical idea provided by the present invention. Therefore, the scope of rights of the present invention should be determined by the claims described below.

100: metal mask 120: mask sheet
120a: Top surface of mask sheet 120b: Bottom surface of mask sheet
125: mask pattern hole 140: first etching groove
160: second etching groove 180: half pattern
L: Laser processing surface T: Cell end portion of mask sheet
MA: Mask cell area DA: Dummy area

Claims (2)

(a) forming a first mask pattern and a second mask pattern on the upper and lower surfaces of a mask sheet having a mask cell region and a dummy region disposed outside the mask cell region;
(b) forming a first etching groove having a tapered cross-section whose thickness increases from the top to the bottom of the mask sheet on the upper surface of the mask sheet by primary etching using the first and second mask patterns;
(c) removing the first and second mask patterns from the mask sheet on which the first etching groove is formed, and then forming a third mask pattern and a fourth mask pattern on the exposed upper and lower surfaces of the mask sheet;
(d) removing a portion of the upper and lower surfaces of the mask sheet through secondary etching using the third and fourth mask patterns, and having a tapered cross-section whose thickness increases from the lower surface to the upper surface of the mask sheet. After forming grooves and mask pattern holes, removing the third and fourth mask patterns; and
(e) removing part of the cell end portions of the mask sheet located on both opposing sides of the mask pattern hole through laser processing to form a bluntly cut laser processing surface. A method of manufacturing a metal mask for OLED deposition, comprising:
In step (e), the laser processing uses an ultrashort pulse laser, which is a femto second or pico second pulse laser,
In step (e), the laser processing surface is provided by selectively removing only the sharp portions of the ends of the cells produced by two-step processing to form a berm by laser processing,
The laser processing surface is disposed at the cell end portion of the mask sheet located at both opposite ends of the mask pattern hole, and is located at the inner end portion of the first etching groove disposed on the upper surface of the mask sheet, thereby forming a glass substrate. Even if sagging occurs due to the load of the metal mask for OLED deposition during the process of depositing organic materials, the glass substrate is prevented from being damaged,
In step (e), the laser processing surface is formed to be inclined at an angle of 50 to 80° with respect to the upper surface of the mask sheet by performing laser processing at an oblique angle. Cell by two-step processing, characterized in that Method of manufacturing a metal mask for OLED deposition with improved edge sharpness.
According to paragraph 1,
In step (e),
(e-1) aligning the laser processing device to the upper part spaced apart from the cell end portions of the mask sheet located on both opposing sides of the mask pattern hole;
(e-2) laser processing by locally irradiating only cell end portions of the mask sheet with a laser beam from the laser processing device; and
(e-3) removing a portion of the cell end portion of the mask sheet through the laser processing to form a bluntly cut laser processing surface;
A method of manufacturing a metal mask for OLED deposition with improved sharpness of the cell end by two-step processing, comprising: