WO2021096115A1

WO2021096115A1 - Mask for manufacturing oled, and oled manufacturing method

Info

Publication number: WO2021096115A1
Application number: PCT/KR2020/014922
Authority: WO
Inventors: 박진원; 이영호
Original assignee: (주)더숨
Priority date: 2019-11-11
Filing date: 2020-10-29
Publication date: 2021-05-20
Also published as: CN114555854A

Abstract

The present invention relates to an OLED mask and an OLED manufacturing method. A mask for manufacturing an OLED, according to the present invention, comprises: a mask housing of which at least one side is open and which provides space in which a deposition source supply part is arranged; and a mask sheet, which is provided on the open one side of a mask housing and has a plurality of mask patterns formed thereon.

Description

OLED manufacturing mask and OLED manufacturing method

The present invention relates to an OLED manufacturing mask and an OLED manufacturing method. More specifically, it relates to a mask for manufacturing an OLED and a method for manufacturing an OLED capable of performing organic material deposition for realizing a high-resolution pixel.

As a technology for forming pixels in the OLED manufacturing process, the FMM (Fine Metal Mask) method is mainly used in which an organic material is deposited at a desired location by attaching a thin metal mask to a substrate.

In the existing OLED manufacturing process, after manufacturing a mask thin film, the mask is welded and fixed to the OLED pixel deposition frame, but there is a problem in that the large-area mask is not well aligned in the fixing process. In addition, in the process of welding and fixing the frame, since the thickness of the mask film is too thin and has a large area, there is a problem that the mask is struck or warped by a load.

In the ultra-high-definition OLED manufacturing process, even a minute alignment error of several µm can lead to pixel deposition failure. Therefore, it is necessary to develop a technology that can prevent deformation such as the mask being struck or distorted, and to clarify the alignment. Actually.

Meanwhile, recently, a micro display applied to a virtual reality (VR)/augmented reality (AR) device has attracted attention. In order to display an image right in front of the user's eyes in a VR/AR device, the micro-display must have a smaller screen size than conventional displays, and must implement high quality within a small screen. Accordingly, a mask pattern having a smaller size than a mask used in a conventional ultra-high-definition OLED manufacturing process and a finer alignment of the mask before the pixel deposition process are required.

Accordingly, the present invention has been devised to solve the problems of the prior art as described above, and an object of the present invention is to provide a mask for manufacturing an OLED and a method for manufacturing an OLED capable of implementing ultra-high-resolution pixels.

In addition, an object of the present invention is to provide an OLED manufacturing mask and an OLED manufacturing method that can facilitate the alignment of the mask even when manufacturing a large area OLED.

It is an object of the present invention, at least one side is open and a mask housing to provide a space for disposing the deposition source supply; And a mask sheet installed on the open side of the mask housing and having a plurality of mask patterns formed thereon.

An organic material source may be generated to form an OLED pixel in the deposition source supply unit, and the organic material source may pass through the mask pattern of the mask sheet to form a pixel on the target substrate.

The target substrate is a silicon wafer, and a mask cell including a plurality of mask patterns may be formed to correspond to at least one or a plurality of die regions on the silicon wafer.

The resolution of the mask pattern may be at least 1,000 pixels per inch (PPI).

The material of the mask sheet may be any one of Invar, Super Invar, and Nickel Alloy.

It may further include a heating means for heating the mask sheet.

The mask sheet is made of a conductive material, and heating may be performed through electrical connection to the mask sheet or application of an induced magnetic field.

It may further include a shutter unit installed to face the mask sheet and formed with an opening to cover at least a portion of the mask sheet.

The opening includes a plurality of unit openings, and each unit opening may correspond to one or a plurality of die regions of the target substrate.

And, the above object of the present invention, (a) arranging the mask to correspond to the target substrate; (b) depositing pixels on a target substrate by supplying an organic material source from a deposition source supply unit disposed in the mask, wherein the mask includes: a mask housing having at least one side open and providing a space for disposing the deposition source supply unit; And a mask sheet installed on an open side of the mask housing and on which a plurality of mask patterns are formed.

The target substrate is a silicon wafer, and some regions may correspond to one or more die regions.

Step (a) includes: disposing a mask cell including a plurality of mask patterns to correspond to at least one or a plurality of die regions on a target substrate; and step (b) includes, (b1) corresponding to a mask cell Depositing a pixel on at least one or a plurality of die regions on the target substrate to be formed; And (b2) moving the mask cell or the target substrate, disposing the mask cell to correspond to at least one or more other die regions on the target substrate, and then depositing a pixel.

According to the present invention configured as described above, there is an effect of implementing an ultra-high definition pixel.

In addition, according to the present invention, there is an effect of facilitating the alignment of the mask even when manufacturing a large area OLED.

1 is a schematic diagram showing a conventional OLED manufacturing process.

2 is a schematic diagram showing a mask according to an embodiment of the present invention.

3 is a schematic diagram showing a mask according to another embodiment of the present invention.

4 is a schematic diagram showing an OLED manufacturing process according to an embodiment of the present invention.

5 to 7 are schematic diagrams showing an OLED manufacturing process according to another embodiment of the present invention.

10: mask

20: mask sheet

30: mask housing

40: heating means

50: shutter unit

51, 52, 53: opening, unit opening

500: deposition source supply

600: organic source

700: pixel

900: target substrate

1000: OLED pixel deposition device

C: mask cell

DM: dummy

P: mask pattern

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention described below refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other, but need not be mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in relation to one embodiment. In addition, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description to be described below is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all ranges equivalent to those claimed by the claims. In the drawings, similar reference numerals refer to the same or similar functions over various aspects, and the length, area, thickness, and the like may be exaggerated for convenience.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily implement the present invention.

1 is a schematic diagram showing a conventional OLED manufacturing process.

Referring to FIG. 1, the OLED pixel deposition apparatus 1000 includes a magnet plate 300 in which a magnet 310 is accommodated and a cooling water line 350 is disposed, and an organic material source 600 from a lower portion of the magnet plate 300. It includes a deposition source supply unit 500 to supply ).

A target substrate 900 such as glass on which the organic material source 600 is deposited may be interposed between the magnet plate 300 and the source deposition unit 500. A mask 100 (or FMM) that allows the organic material source 600 to be deposited for each pixel may be disposed on the target substrate 900 to be in close contact or very close to each other. The magnet 310 generates a magnetic field and may be in close contact with the target substrate 900 by the magnetic field.

The deposition source supply unit 500 may reciprocate the left and right path to supply the organic material source 600, and the organic material sources 600 supplied from the deposition source supply unit 500 pass through the pattern P formed on the mask 100 It may be deposited on one side of the target substrate 900. The deposited organic material source 600 passing through the pattern P of the mask 100 may function as the pixel 700 of the OLED.

In order to prevent non-uniform deposition of the pixel 700 due to a shadow effect, the pattern of the mask 100 may be formed to be inclined (S) (or formed in a tapered shape (S)). Organic material sources 600 passing through the pattern in a diagonal direction along the inclined surface may also contribute to the formation of the pixel 700.

However, the conventional mask 100 as shown in FIG. 1 has a size corresponding to the target substrate 900 having a large area. Since the mask 100 is a large area including a plurality of cells (patterns corresponding to the die) and has a very thin thickness of several tens of µm, it is easily struck or distorted by a load. In addition, it is very difficult to check the alignment between the cells in real time through a microscope while adjusting the tensile force to make all the cells flat.

In addition, since the organic material sources 600 are deposited on the target substrate 900 having a large area, it is not easy to deposit accurately enough to spread out and implement an ultra-high-definition pixel. In other words, since pixels corresponding to a plurality of cells of the target substrate 900 are formed through one deposition source supply unit 500, there is a problem that the organic material source 600 spreads without being concentrated in a specific cell.

In the present invention, in order to implement a microdisplay applied to a VR/AR device, a pixel deposition process may be performed on a silicon wafer rather than a large-area target substrate 900. Since the screen is positioned directly in front of the user's eyes, the micro-display has a screen that is about 1 to 2 inches smaller than the size of a large area. In addition, since it is located close to the user's eyes, the resolution needs to be implemented higher. Accordingly, the present invention is preferably considered to be performed on a silicon wafer of 200mm, 300mm, 450mm class, rather than used in the pixel formation process for the target substrate 900 of a large area.

For example, in the case of current QHD quality, the size of the pixel reaches about 30-50㎛ with 500~600 PPI (pixel per inch), and in the case of 4K UHD and 8K UHD high quality, ~860 PPI, ~1600 PPI, which is higher. And so on. Micro-displays applied directly to VR/AR devices, or micro-displays inserted into VR/AR devices, aim for ultra-high quality of about 1,000 PPI or higher, preferably about 2,000 PPI or higher, and the size of the pixel is about 5 It reaches about ~10㎛. In the case of a silicon wafer, it is advantageous to be employed as a substrate for a high-resolution micro-display because it enables a finer and more precise process compared to a glass substrate by utilizing the technology developed in the semiconductor process.

2 is a schematic diagram showing a mask according to an embodiment of the present invention. Fig. 2(a) shows a schematic cross-sectional view of the mask, and Fig. 2(b) shows a schematic plan view of the mask sheet 20.

Referring to FIG. 2, the mask 10 of the present invention includes a mask sheet 20 and a mask housing 30.

The mask sheet 20 has a mask pattern P formed on the mask body 21 and may play a role of a mask for masking and passing the organic material source 600. The mask sheet 20 may include a mask cell C on which a plurality of mask patterns P are formed and a dummy DM surrounding the mask cell C. The mask sheet 20 may be a coefficient of thermal expansion of about 1.0 X 10 ^-6 / ℃ of invar (invar), about 1.0 X 10 ^-7 / ℃ Super Invar (super invar) material. Since the mask sheet 20 made of this material has a very low coefficient of thermal expansion, it is less likely that the pattern shape of the mask is deformed by thermal energy, and thus can be used as a mask in high-resolution OLED manufacturing. In addition, considering the recent development of technologies for performing the pixel deposition process in a range where the temperature change value is not large, the mask sheet 20 is made of nickel (Ni) and nickel-cobalt (Ni- It may be a material such as Co).

The mask sheet 20 may be manufactured from a metal sheet produced by a rolling process or electroplating, and one or a plurality of mask cells C may be formed on the mask sheet 20. The mask cell C may be understood as a unit constituting one display or forming a pixel in one or a plurality of die regions of a silicon wafer. The dummy DM corresponds to a portion of the mask body 21 excluding the cell C, and includes only the mask body 21, or the mask body 21 in which a predetermined dummy pattern similar to the mask pattern P is formed. It may include. In the dummy DM, part or all of the dummy DM may be connected to the mask housing 30 in correspondence with the edge of the mask sheet 20. As described above, it is preferable that the mask pattern P is formed with a resolution of 1,000 PPI (pixel per inch) or more, preferably 2,000 to 3,000 PPI level or more so as to implement an ultra-high resolution OLED. To this end, the width of the mask pattern P may be about 2 to 20 μm, and the thickness of the mask sheet 20 may be about 2 to 20 μm. The pitch between the mask patterns P may be formed to be about 2 to 20 μm.

The mask housing 30 may have an empty interior and one side of the mask housing 30 open. A mask sheet 20 may be installed on one open side (eg, upper portion). The mask sheet 20 may be attached by welding or may be installed on the mask housing 30 through an adhesive means, a binding means, or the like. It is preferable that the size of the opening of the mask housing 30 corresponds to the mask sheet 20. The mask housing 30 is preferably formed of the same material as the mask sheet 20 and has the same thermal behavior (thermal flattening coefficient) in terms of pixel accuracy, but is not limited thereto. The mask housing 30 may have a size corresponding to one or a plurality of die regions of the target substrate 900, preferably, a wafer for implementing an ultra-high resolution OLED. The same is true for the size of the mask sheet 20.

The mask housing 30 may provide a space in which the deposition source supply unit 500 generating the organic material source 600 is disposed. In another aspect, the mask housing 30 may limit the space through which the organic material source 600 spreads. The deposition distance between the deposition source supply unit 500 disposed in the mask housing 30 and the target substrate 900 may be about 200 mm to 500 mm. It is preferable that the mask housing 30 is formed in a shape having a ratio having a larger vertical length than a horizontal width so that the movement path of the organic material source 600 can induce an angle close to the vertical as much as possible.

The organic material source 600 generated by the deposition source supply unit 500 generally rises in a vertical direction, and may rise at an angle within 0° to 50° based on a generally vertical direction. As shown in FIG. 1, when the deposition source supply unit 500 performs deposition at a distance from the target substrate 900, a significant portion of the organic material source 600 is spread at a large angle, and the deposition source supply unit 500 moves horizontally. Even if the deposition is performed while doing so, it is not desirable for intensive and detailed pixel formation. Therefore, it is important to consider that the organic material source 600 in the largest proportion as possible moves close to 0° based on the vertical direction.

In the present invention, the organic material source 600 generated from the deposition source supply unit 500 may move within the mask housing 30 and pass through the mask pattern P of the mask sheet 20 to be deposited on the target substrate 900. have. That is, since the organic material source 600 can be deposited by limited to the open side of the mask housing 30 or the size of the mask sheet 20, there is an advantage of realizing detailed deposition and thus realizing an ultra-high resolution OLED. have. In addition, since the path through which the organic material source 600 moves can be guided in the vertical direction according to the shape of the mask housing 30, there is an advantage that more detailed deposition is possible. In addition, since the mask sheet 20 can be made small without the need to have a large size corresponding to the target substrate 900 and supported on the mask housing 30, the mask sheet 20 is struck by a load or is not aligned. There is an advantage of minimizing the possibility of misalignment and improving clarity of alignment with respect to the mask sheet 20 having a small size.

The deposition source supply unit 500 is disposed inside the mask housing 30 to supply the organic material source 600 to the top, and the organic material sources 600 supplied from the deposition source supply unit 500 are formed on the mask sheet 20. It may be deposited on one side of the target substrate 900 by passing through the pattern P. The deposited organic material source 600 passing through the pattern P of the mask 100 may function as the pixel 700 of the OLED.

Meanwhile, when the deposition process of the OLED pixel 700 is repeatedly performed as shown in FIG. 3A, the organic material source 610 may gradually accumulate on the mask body 21. The thicker the organic material source 610 is accumulated on the mask sheet 20, the more the size of the mask pattern P may be affected. The width may be reduced to R2 by the organic material source 610 in which the mask pattern P having the width R1 is accumulated. Accordingly, after several hundred deposition processes, the accumulated organic material source 610 is removed through a process of cleaning the mask, but this may cause a decrease in productivity and damage the mask sheet 20.

Accordingly, as shown in FIG. 3B(b), the mask according to another embodiment is characterized in that it further includes a heating means 40 for heating the mask sheet 20. As the heating means 40 heats a portion of the mask sheet 20 to maintain a predetermined temperature, the organic material source 600 is volatilized to prevent the organic material source 600 from condensing or accumulating on the mask sheet 20. I can. As the heating means 40, a known means capable of heating the mask sheet 20 may be used. Or, as an example, considering that the mask sheet 20 is made of a conductive material such as Invar or super invar nickel alloy, heating is performed through direct electrical connection to the mask sheet 20 or , Heating can also be performed through the application of an induced magnetic field.

4 is a schematic diagram showing an OLED manufacturing process according to an embodiment of the present invention

Referring to FIG. 4A, first, the mask 10 (or the mask cell C) may be mapped to a specific die area of the target substrate 900 to be deposited. A specific die area may correspond to one die area or a plurality of die areas, such as two or four. As an example, the pixel 700 may be formed by depositing an organic material source 600 corresponding to the mask 10 for one die area. The mask 10 intensively deposits the organic material source 600 in a limited space corresponding to one die, and at the same time, the mask sheet 20 also has a mask pattern P having a resolution corresponding to ultra-high quality, so 1,000 PPI As described above, the pixel 700 can be formed.

Next, referring to FIG. 4B, the mask 10 may be moved (S1) to a specific die area of the next target to be deposited. While the mask 10 is fixed without moving, the target substrate 900 (for example, a wafer) may be moved (S2). Movement means not only the X, Y, and Z axes, but also the angle adjustment (θ) based on the XY, YZ, and ZX planes. In addition, a pixel 700 may be formed in the corresponding die area of the target substrate 900. By repeating this process, the mask 10 intensively deposits an organic material source 600 on a limited area corresponding to one die or a few dies, and after moving the position, the organic material source 600 is again in the corresponding die area. It becomes possible to deposit intensively. Accordingly, the pixel 700 can be formed in ultra-high quality for all die regions of the target substrate 900.

The mask 10 may further include a shutter unit 50. 5 to 7 illustrate that the shutter unit 50 is disposed between the mask 10 and the target substrate 900, the shutter unit 50 is coupled to the mask 10 so that the opening 51 It may be a configuration that changes the location.

The shutter unit 50 may be installed to face the mask sheet 20. That is, it may be disposed between the mask sheet 20 and the target substrate 900 to face each other so as to cover at least a part of the mask sheet 20. The shutter unit 50 may be installed to move (S1) in the horizontal direction with respect to the mask 10. Alternatively, the shutter unit 50 may be fixed (eg, fixedly installed on the mask 10), and the target substrate 900 may be moved (S2).

The shutter unit 50 may have an opening 51 formed therein. The opening 51 may be formed to have a size smaller than that of the mask sheet 20 so as to cover at least a portion of the mask sheet 20. Alternatively, as the shutter unit 50 is installed under the mask sheet 20, that is, inside the mask housing 30, at least a part of the mask sheet 20 may be covered.

For example, when the mask sheet 20 includes two cells C, the opening 51 may be formed to have a size corresponding to only one cell C. Since the opening 51 allows only one cell (C) to be opened and the other cell (C) is covered, the organic material source 600 generated by the mask 10 is an opening corresponding to one cell (C). It may be deposited on the target substrate 900 only through 51.

Accordingly, even if the size of the mask sheet 20 is not changed, the size of the opening 51 of the shutter unit 50 is changed, or the opening 51 covers the portions where the shutter unit 50 covers the mask sheet 20. By changing it, there is an advantage that the deposition area can be freely changed.

Referring to FIG. 5A, first, the mask 10 may correspond to the target substrate 900 to be deposited, and the opening 51 may correspond to a specific die region using the shutter unit 50. A specific die area may correspond to one die area or a plurality of die areas, such as two or four. For example, the pixel 700 may be formed by depositing an organic material source 600 corresponding to the opening 51 in one die area.

Next, referring to FIG. 5B, the mask 10 may be moved to a specific die area of the next target to be deposited. As much as the mask 10 has moved, the opening 51 of the shutter unit 50 is also moved to form the pixel 700 for the corresponding die area. By repeating this process, the pixel 700 may be formed in ultra-high quality for all die regions of the target substrate 900.

Referring to FIG. 6A, the opening of the shutter unit 50 may include not one, but a plurality of

unit openings

52 and 53. Each of the

unit openings

52 and 53 may correspond to one or a plurality of die regions of the target substrate 900. Accordingly, even if the mask pattern P is formed on the mask sheet 20 so that the mask pattern P forms one cell (C) without distinction of several cells (C), the

unit openings

52 and 53 It can be positioned so that cells can be distinguished. Consequently, even with one mask sheet 20, pixel deposition for several cells C may be possible.

As an example, the organic material source 600 may be deposited in correspondence with the two

unit openings

52 and 53 in the shutter unit 50 for the two die regions. Pixels 700 for two die regions (or two displays) may be formed in one deposition process.

Next, referring to FIG. 6B, the mask 10 may be moved to a specific die area of the next target to be deposited. As much as the mask 10 has moved, the

openings

52 and 53 of the shutter unit 50 are also moved to form the pixel 700 for the corresponding die area. By repeating this process, there is an advantage in that the pixels 700 for two die regions can be formed in ultra-high quality every time.

Referring to FIG. 7A, first, the mask 10 may correspond to the target substrate 900 to be deposited, and the opening 51 may correspond to a specific die region using the shutter unit 50. A specific die area may correspond to one die area or a plurality of die areas, such as two or four. As an example, the pixel 700 may be formed by depositing an organic material source 600 corresponding to the opening 51 for one die area.

Next, referring to FIG. 7B, the position of the mask 10 is fixed, and the target substrate 900 may be moved (S2) to a position where the specific die region and the mask 10 correspond to each other. The shutter unit 50 may be in a state in which the opening 51 is closed.

Next, referring to FIG. 7C, the opening 51 of the shutter unit 50 is opened, and an organic material source 600 is deposited on a specific die region corresponding to the opening 51 to form a pixel ( 700) can be formed. By repeating this process, the pixel 700 may be formed in ultra-high quality for all die regions of the target substrate 900.

As described above, according to the present invention, it is possible to implement ultra-high-definition pixels, and there is an effect of facilitating the alignment of the mask even when manufacturing a large-area OLED.

Although the present invention has been illustrated and described with reference to a preferred embodiment as described above, it is not limited to the above embodiment, and within the scope not departing from the spirit of the present invention, various It can be transformed and changed. Such modifications and variations should be viewed as falling within the scope of the present invention and the appended claims.

Claims

A mask housing having at least one side open and providing a space for disposing the deposition source supply unit; And

A mask sheet installed on the open side of the mask housing and having a plurality of mask patterns formed thereon

Containing, OLED manufacturing mask.
The method of claim 1,

A mask for manufacturing an OLED, in which an organic material source is generated to form an OLED pixel in a deposition source supply unit, and the organic material source passes through a mask pattern of a mask sheet to form a pixel on a target substrate.
The method of claim 2,

The target substrate is a silicon wafer, and a mask cell including a plurality of mask patterns is formed to correspond to at least one or a plurality of die regions on the silicon wafer.
The method of claim 1,

The resolution of the mask pattern is at least 1,000 PPI (Pixel Per Inch) greater than, OLED manufacturing mask.
The method of claim 1,

The material of the mask sheet is any one of Invar, Super Invar, and Nickel Alloy, an OLED manufacturing mask.
The method of claim 1,

A mask for manufacturing an OLED, further comprising a heating means for heating the mask sheet.
The method of claim 6,

The mask sheet is a conductive material, and heating is performed through an electrical connection or application of an induced magnetic field to the mask sheet, an OLED manufacturing mask.
The method of claim 1,

A mask for manufacturing an OLED, further comprising a shutter unit installed opposite to the mask sheet and formed with an opening to cover at least a portion of the mask sheet.
The method of claim 8,

The opening includes a plurality of unit openings, each unit opening corresponding to one or a plurality of die regions of the target substrate.
(a) arranging the mask to correspond to a partial area of the target substrate;

(b) depositing a pixel on a partial region of the target substrate by supplying an organic material source from a deposition source supply unit disposed in the mask;

Including,

The mask includes: a mask housing having at least one side open and providing a space for disposing a deposition source supply unit; And a mask sheet installed on an open side of the mask housing and having a plurality of mask patterns formed thereon.
The method of claim 10,

The target substrate is a silicon wafer and some regions correspond to one or a plurality of die regions.
The method of claim 11,

Step (a) includes: disposing a mask cell including a plurality of mask patterns to correspond to at least one or a plurality of die regions on a target substrate; and

Step (b) includes: (b1) depositing a pixel in at least one or a plurality of die regions on a target substrate corresponding to the mask cell; And (b2) moving the mask cell or the target substrate and disposing the mask cell to correspond to the other at least one or a plurality of die regions on the target substrate, and then depositing a pixel.