TW201946311A - Manufacturing method of mask, buffer substrate for supporting mask and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a buffer substrate for supporting a mask, a method for manufacturing same, and a method for manufacturing a frame-integrated mask. The method for manufacturing a buffer substrate for supporting a mask according to the present invention, which is a method for manufacturing a buffer substrate that supports a mask for forming OLED pixels and makes the mask correspond to a frame, comprises: (a) a step for providing a mask metal film; (b) a step for adhering the mask metal film onto the buffer substrate having a temporary adhesive portion formed on a surface thereof; (c) a step for forming a mask pattern on the mask metal film; and (d) a step for separating, from the buffer substrate, the mask metal film having the mask pattern formed therein.

Description

Manufacturing method of mask, mask supporting buffer substrate and manufacturing method thereof

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a mask, a mask supporting buffer substrate, and a method for manufacturing the same. More specifically, it relates to a manufacturing method of a mask capable of stably forming a pattern on a mask and stably supporting and moving the mask without deforming it, a mask supporting buffer substrate, and a manufacturing method thereof.

BACKGROUND OF THE INVENTION As a technology for forming pixels in an OLED (Organic Light Emitting Diode) manufacturing process, a FMM (Fine Metal Mask, fine metal mask) method is mainly used. ) Close to the substrate and deposit organics on the desired location.

In ultra-high-definition OLEDs, the current QHD (Quarter High Definition) image quality is 500-600PPI (pixel per inch), the pixel size is about 30-50μm, and 4K UHD ( Ultra High Definition (Ultra High Definition) and 8K UHD have higher resolutions of ~ 860PPI, ~ 1600PPI, etc. In this way, considering the pixel size of the ultra-high-definition OLED, it is necessary to reduce the alignment error between the units to several μm, beyond which the product will be defective, so the yield may be extremely low. Therefore, it is necessary to develop a technique capable of preventing deformation of the mask from sagging or twisting, and achieving accurate alignment, a technique of fixing the mask to a frame, and the like.

SUMMARY OF THE INVENTION Technical Problem Accordingly, the present invention has been made in order to solve the above-mentioned problems in the prior art, and an object thereof is to provide a method for manufacturing a mask capable of stably forming a pattern on a mask.

Another object of the present invention is to provide a mask supporting buffer substrate and a manufacturing method thereof, which can stably support and move the mask without deforming it.
Technical solutions

The above object of the present invention is achieved by a mask manufacturing method for manufacturing a mask for forming an OLED pixel, which includes the following steps: (a) providing a mask metal film; (b) applying the mask metal film Adhered to a buffer substrate having a temporary adhesive portion formed on its surface; (c) forming a mask pattern on the mask metal film; (d) separating the mask on which the mask pattern is formed from the buffer substrate Mold metal film.

The mask metal film may be formed by rolling or electroforming.

The step (b) and the step (c) may further include a step of reducing a thickness of the mask metal film adhered to the buffer substrate.

When the mask metal film is formed by the electroforming, the step (a) may include the following steps: (a1) forming the mask metal film on at least one surface of a conductive single crystal substrate; and (A2) The mask metal film is separated from the conductive single crystal substrate.

Between the step (a1) and the step (a2), a step of heat-treating the mask metal film may be further included.

The temporary adhesive portion may be an adhesive or an adhesive sheet that can be separated by heating, an adhesive or an adhesive sheet that can be separated by UV irradiation.

The temporary adhesive portion may be a liquid wax or a thermal release tape.

The liquid wax may fix and adhere the mask metal film and the buffer substrate at a temperature lower than 85 ° C.

In the step (b), the liquid wax may be heated to more than 85 ° C, and after the mask metal film contacts the buffer substrate, the mask metal film and the buffer substrate are passed through two Between the two rollers for bonding.

In the step (b), before the mask metal film is adhered, a laser passing hole may be formed in a portion of the buffer substrate corresponding to a soldered portion of the mask.

The step (c) may include the following steps: (c1) forming a patterned insulating portion on the mask metal film; (c2) forming a mask metal film exposed from between the insulating portions Etching is partially performed to form the mask pattern; and (c3) removing the insulating portion.

In the step (d), the temporary bonding portion may be subjected to at least one of heating, chemical treatment, application of ultrasonic waves, and application of UV to separate the mask metal film and the buffer substrate.

In step (d), any one of solvent debonding, heat debonding, peelable adhesive debonding, and room temperature debonding may be performed. .

In addition, the object of the present invention is achieved by a mask supporting a buffer substrate for supporting a mask for forming an OLED pixel. The mask supporting buffer substrate includes: a buffer substrate; and a temporary adhesive portion formed on the buffer substrate. And a mask to form a mask pattern and adhere to the buffer substrate through the temporary adhesive portion.

The thickness of the mask metal film may be 5 μm to 20 μm.

The temporary adhesive portion may be an adhesive or an adhesive sheet that can be separated by heating, an adhesive or an adhesive sheet that can be separated by UV irradiation.

The buffer substrate may include a wafer, glass, silica, heat-resistant glass, quartz, Al ₂ O ₃ , borosilicate glass, and zirconia. (Zirconia).

A laser passing hole may be formed in a portion of the buffer substrate and the temporary adhesive portion corresponding to a soldered portion of the mask.

The mask may include one or more mask units formed with a plurality of the mask patterns.

In addition, the object of the present invention is achieved by a manufacturing method of a mask supporting buffer substrate, which is used for manufacturing a buffer substrate that supports an OLED pixel formation mask so as to correspond to a frame, and is characterized in that: The method includes the following steps: (a) providing a mask metal film; (b) adhering the mask metal film on a buffer substrate having a temporary adhesive portion formed on the surface; and (c) forming a mask on the mask metal film. Pattern to make a mask.

ADVANTAGE OF THE INVENTION According to this invention comprised as mentioned above, it has the effect that a mask pattern can be formed stably.

In addition, according to the present invention, it is possible to stably support and move the mask without deforming it.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention to be described later will refer to the accompanying drawings, which show specific embodiments capable of implementing the present invention as examples. These embodiments are described in sufficient detail to enable those skilled in the art to implement the invention. It should be understood that although various embodiments of the present invention are different from each other, they are not necessarily mutually exclusive. For example, the specific shapes, structures, and characteristics described herein are related to one embodiment, and can be implemented in other embodiments without departing from the spirit and scope of the invention. In addition, it should be understood that the position or arrangement of individual constituent elements in each disclosed embodiment can be changed without departing from the spirit and scope of the present invention. Therefore, the detailed description described below should not be regarded as limiting. As long as it is properly described, the scope of the present invention is limited only by the scope of the attached patent application and all equivalent scopes thereof. Similar reference numerals in the figure represent the same or similar functions from various aspects. For convenience, the length, area, thickness, and shape can be exaggerated.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the present invention.

FIG. 1 is a schematic view showing a conventional mask 10 for OLED pixel deposition.

Referring to FIG. 1, the existing mask 10 may be manufactured in a stick-type or a plate-type. The mask 10 shown in (a) of FIG. 1 is used as a stripe mask, and both sides of the stripe can be welded and fixed to the OLED pixel deposition frame and used. The mask 100 shown in FIG. 1 (b) is used as a plate mask, which can be used for a large area pixel formation process, and the edge of the plate can be welded and fixed to the OLED pixel deposition frame 200 (see FIG. 11). FIG. 1 (c) is an enlarged side sectional view of the AA ′ portion.

The main body (body or mask film 11) of the mask 10 includes a plurality of display units C. One unit C corresponds to one display of a smartphone or the like. A pixel pattern P (mask pattern P) is formed in the unit C so as to correspond to each pixel of the display. When the unit C is enlarged, a plurality of pixel patterns P corresponding to R, G, and B are displayed. As an example, a pixel pattern P is formed in the cell C so as to have a resolution of 70 × 140. That is, a large number of pixel patterns P are formed to form a unit C, and a plurality of units C may be formed on the mask 10.

The mask pattern P may have a shape in which sides are inclined, and a tapered shape. Preferably, the mask pattern P has a shape in which the width increases or decreases from the upper part to the lower part, that is, the shape is substantially tapered. More preferably, since the upper surface of the mask 100 is in close contact with the target substrate 900 (refer to FIG. 11), the mask pattern P has a shape in which the width increases from the upper part to the lower part.

FIG. 2 is a schematic view showing a conventional mask for forming a high-resolution OLED.

In order to achieve a high-resolution OLED, the size of the pattern is decreasing, and for this purpose, the thickness of the mask metal film used needs to be reduced. As shown in (a) of FIG. 2, in order to achieve a high-resolution OLED pixel 6, the pixel pitch and the pixel size should be reduced in the mask 10 ′ (PD-> PD ′). In addition, in order to prevent the OLED pixels 6 from being unevenly deposited due to the shadow effect, the pattern of the mask 10 ′ needs to be formed obliquely 14. However, in the process of forming 14 patterns obliquely on a thick mask 10 'having a thickness of T30 of about 30-50 μm, it is difficult to achieve patterning 13 suitable for fine pixel pitch PD' and pixel size, resulting in a decrease in yield during processing. . In other words, in order to have a fine pixel pitch PD ′ and to form the 14 pattern obliquely, a thin mask 10 ′ should be used.

In particular, for UHD level high resolution, as shown in (b) of FIG. 2, a thin mask 10 ′ having a thickness T2 of 20 μm or less should be used for fine patterning. In addition, for ultra-high resolution above UHD, it may be considered to use a thin mask 10 ′ having a thickness T2 of 10 μm.

3 to 7 are schematic views showing a manufacturing process of a mask according to an embodiment of the present invention.

Hereinafter, a series of processes for manufacturing the mask metal film 110 ′ and supporting it on the buffer substrate 50 to manufacture the mask 100 will be described.

FIG. 3 is a schematic view showing a process of manufacturing a mask metal film according to an embodiment of the present invention by rolling. FIG. 4 is a schematic diagram illustrating a process of manufacturing a mask metal film according to another embodiment of the present invention by electroforming.

First, a mask metal film 110 may be prepared. As an example, the mask metal film 110 may be prepared in a rolling manner.

Referring to FIG. 3 (a), a metal sheet produced through a rolling process may be used as the mask metal film 110 ′. The metal sheet word manufacturing process manufactured by the rolling process may have a thickness of several tens to several hundreds of μm. As shown in FIG. 2, for UHD level high resolution, a thin mask metal film 110 with a thickness of 20 μm or less should be used for fine patterning. For ultra high resolution above UHD, a thickness of A thin mask metal film 110 of 10 μm. However, since the thickness of the mask metal film 110 ′ produced by the rolling process is about 25 to 500 μm, it is necessary to make it thinner.

Therefore, a step of planarizing PS of one surface of the mask metal film 110 'can be further performed. Among them, the planarization PS means that while one surface (upper surface) of the mask metal film 110 ′ is mirror-finished, a part of the upper portion of the mask metal film 110 ′ is removed, thereby reducing the thickness. The planarization PS can be performed by a CMP (Chemical Mechanical Polishing) method, and a known CMP method can be used without limitation. In addition, the thickness of the mask metal film 110 ′ can be reduced by a chemical wet etching method or a dry etching method. In addition, a planarization step capable of reducing the thickness of the mask metal film 110 'can be used without limitation.

During the implementation of the planarization PS, the surface roughness R _{a of the} upper surface of the mask metal film 110 ′ can be controlled in the CMP process as an example. Preferably, specularization can be performed to further reduce the surface roughness. Or, as another example, after performing a chemical wet etching or dry etching in the planarization process PS, you can add other like polishing step CMP process to reduce surface roughness R _a.

In this way, the thickness of the mask metal film 110 ′ can be reduced to about 50 μm or less. Therefore, preferably, the thickness of the mask metal film 110 is formed to be about 2 μm to 50 μm, and more preferably, the thickness may be formed to be about 5 μm to 20 μm. However, it is not necessarily limited to this.

Referring to FIG. 3 (b), similarly to FIG. 3 (a), the thickness of the mask metal film 110 ′ manufactured by the rolling process can be reduced to produce the mask metal film 110. However, the mask metal film 110 ′ may be reduced in thickness by performing a planarization PS process in a state where the mask metal film 110 ′ is adhered by the temporary adhesive portion 55 on a buffer substrate 50 described later.

As another embodiment, the mask metal film 110 may be prepared by an electroforming method.

Referring to FIG. 4A, a conductive substrate 21 is prepared. The base material 21 of the mother board may be a conductive material so that electroforming can be performed. The motherboard can be used as a cathode body in electroforming.

As a conductive material, metal can generate metal oxides on the surface, and impurities can flow during the metal manufacturing process. Polycrystalline silicon substrates can have inclusions or grain boundaries. The conductive polymer substrate may contain impurities. It is high-strength, and may be weak in strength and acid resistance. Factors such as metal oxides, impurities, inclusions, grain boundaries, etc. that hinder the uniform formation of an electric field on the surface of the motherboard (or cathode body) are called "Defects". Due to defects, a uniform electric field cannot be applied to the cathode of the material, which may cause a part of the plating film 110 (or the mask metal film 110) to be unevenly formed.

In the realization of UHD pixels above UHD level, the unevenness of the coating film and the coating pattern (mask pattern P) may have a bad influence on the formation of pixels. For example, the current QHD image quality is 500-600PPI (pixel per inch) and the pixel size is about 30-50μm. It has higher quality of 4K UHD and 8K UHD than ~ 860PPI, ~ 1600PPI, etc. Resolution. Mini-displays directly applied to VR devices, or micro-displays used after being inserted into VR devices, aim at high resolutions above 2000PPI, and the pixel size is about 5-10 μm. The pattern width of the FMM and the shadow mask applied thereto can be formed to a size of several μm to several tens of μm, preferably less than 30 μm. Therefore, a defect of a few μm size also occupies a large proportion in the pattern size of the mask. In addition, in order to remove defects of the cathode of the material, an additional process for removing metal oxides, impurities, and the like may be performed, and other defects such as etching of the cathode material may be caused in the process.

Therefore, the present invention can use a mother board (or cathode body) of a single crystal silicon material. In particular, a single crystal silicon material is preferred. The mother board of the single crystal silicon material can be doped at a high concentration of 10 ¹⁹ / cm ³ or more so as to have conductivity. Doping can be performed on the entire mother board or only on a partial surface of the mother board.

On the other hand, for single crystal materials, metals such as Ti, Cu, and Ag; semiconductors such as GaN, SiC, GaAs, GaP, AlN, InN, InP, and Ge; carbon materials such as graphite and graphene; comprising a _{CH 3 NH 3 PbCl 3, CH} 3 NH 3 PbBr 3, CH 3 NH 3 PbI 3, SrTiO 3 perovskite-like (Transition of perovskite) crystal structure with a superconducting ceramics, single crystal superalloy aircraft parts Alloys, etc. Metal and carbon materials are usually conductive materials. The semiconductor material can be doped at a high concentration of 10 ¹⁹ / cm ³ or more so as to have conductivity. Other materials can be doped or oxygen vacancy formed to form conductivity. Doping may be performed on the entire motherboard or only on a part of the surface of the motherboard.

Since the single crystal material has no defects, a uniform plating film 110 is generated due to the formation of a uniform electric field on the entire surface during electroforming. The frame-integrated masks 100 and 200 manufactured by uniform coating can further improve the picture quality level of the OLED pixels. In addition, since no additional steps for removing and eliminating defects are required, it is possible to reduce process costs and improve productivity.

Referring to FIG. 4 (a), the conductive substrate 21 is then used as a mother board (cathode body), and an anode body (not shown) is disposed in a spaced apart manner. The plating film 110 (or the mask metal film 110) is formed by casting. The plating film 110 may be formed on the exposed upper surface and the side surface of the conductive substrate 21, which faces the anode and an electric field may be applied thereto. In addition to the side surface of the conductive base material 21, the plating film 110 may be formed to a part of the lower surface of the conductive base material 21.

Then, the edge portion of the plating film 110 may be cut by laser D, or a photoresist layer may be formed on the upper portion of the plating film 110, and only the exposed plating film 110 is etched to remove D. Therefore, as shown in FIG. 4 (b), the plating film 110 can be separated from the conductive substrate 21.

On the other hand, heat treatment H may be performed before the plating film 110 is separated from the conductive substrate 21. The present invention is characterized in that in order to reduce the thermal expansion coefficient of the mask 100 and prevent thermal deformation of the mask 100 and the mask pattern P, before the plating film 110 (or the mother board, the cathode body) is separated from the conductive substrate 21, Perform heat treatment H. The heat treatment may be performed at a temperature of 300 ° C to 800 ° C.

Generally, the thermal expansion coefficient of an Invar sheet produced by electroforming is higher than that of an Invar sheet produced by rolling. Therefore, heat treatment of the Invar alloy sheet can reduce the thermal expansion coefficient, but peeling, deformation, etc. may occur in the Invar alloy sheet during the heat treatment. This is a phenomenon caused by heat treatment only on the Invar alloy sheet, or only on Invar alloy sheet temporarily adhered to the upper surface of the conductive substrate 21. However, in the present invention, in addition to the upper surface of the conductive substrate 21, the plating film 110 is formed to the side surface and a portion to the lower surface. Therefore, even if the heat treatment H is performed, peeling, deformation, and the like do not occur. In other words, since the heat treatment is performed in a state where the conductive substrate 21 and the plating film 110 are closely adhered, it is possible to prevent peeling, deformation, and the like due to the heat treatment, and to perform the heat treatment stably.

The thickness of the mask metal film 110 generated by the electroforming process can be thinner than that of the rolling process. Therefore, it is possible to omit the planarization PS step of reducing the thickness, but the etching characteristics may be different depending on the composition of the surface layer, the crystal structure, and the fine structure of the plating mask metal film 110 ′. Therefore, the surface characteristics need to be controlled by planarizing the PS ,thickness.

5 to 7 are schematic diagrams illustrating a process of manufacturing a buffer substrate by bonding a mask metal film 110 to a buffer substrate 50 according to an embodiment of the present invention, and forming a mask of the mask 100.

Referring to (a) of FIG. 5, a buffer substrate 50 may be provided. The buffer substrate 500 is a medium that supports the mask metal film 110 when the mask pattern P is formed on the mask metal film 110, or the manufactured mask 100 can be attached to one surface and moved in a supported state. medium. Preferably, one surface of the buffer substrate 50 is flat so as to be able to support the flat mask 100 or the mask metal film 110. The buffer substrate 50 may have a large flat plate shape having an area larger than that of the mask metal film 110 so as to be able to support the entire mask metal film 110.

Preferably, the buffer substrate 50 is a transparent material in order to align the mask 100 with the frame 200 through a subsequent process, and it is easy to visually observe and the like during the bonding process. In addition, transparent materials can also transmit laser light. As the transparent material, glass, silica, heat-resistant glass, quartz, Al ₂ O ₃ , borosilicate glass, and zirconia can be used. ) And other materials. As an example, the buffer substrate 50 can be made of BOROFLOAT ^® 33 material, which has excellent heat resistance, chemical durability, mechanical strength, and transparency among borosilicate glass. In addition, the thermal expansion coefficient of BOROFLOAT ^® 33 is approximately 3.3, and the thermal expansion coefficient of the Invar alloy mask metal film 110 is small, so it is easy to control the mask metal film 110.

On the other hand, a surface of the buffer substrate 50 that is in contact with the mask metal film 110 may be a mirror surface so that an air gap does not occur between an interface with the mask metal film 110 (or the mask 100). In view of this, the surface roughness Ra of one surface of the buffer substrate 50 may be 100 nm or less. In order to realize the buffer substrate 50 having a surface roughness Ra of 100 nm or less, a wafer can be used as the buffer substrate 500. The surface roughness Ra of the wafer is about 10 nm, there are many products on the market, and the surface treatment process is widely known, so it can be used as the buffer substrate 50. Since the surface roughness Ra of the buffer substrate 50 is in the order of nm, there are no voids or almost no gaps, and the weld seam WB is easily generated by laser welding, so that the alignment error of the mask pattern P is not affected.

The buffer substrate 50 may be formed with a laser passing hole (not shown) so that the laser L irradiated from the upper portion of the buffer substrate 50 reaches the soldering portion (area to be soldered) of the mask 100. A laser passing hole (not shown) can be formed in the buffer substrate 50 so as to correspond to the position and the number of the welding portions. Since the plurality of soldering portions are arranged at a predetermined pitch on the edge of the mask 100 or the dummy portion DM, a plurality of laser passing holes (not shown) may be formed at a predetermined pitch in a corresponding manner. As an example, since the plurality of soldering portions 100 are arranged at a predetermined pitch on both sides (left / right) of the dummy portion DM of the mask 100, a plurality of buffer portions 50 may be formed at a predetermined pitch on both sides (left / right). Laser through hole (not shown). On the other hand, a laser passing hole (not shown) may be formed in a state where the temporary adhesive portion 55 is formed on the buffer substrate 50. At this time, a laser passing hole (not shown) may be formed to penetrate the buffer substrate 50 and the temporary bonding portion 55.

The laser passing hole (not shown) does not necessarily correspond to the position and number of the welded portions. For example, only a part of the laser passing hole (not shown) may be irradiated with the laser L to perform welding. When the mask 100 and the buffer substrate 50 are aligned, a part of a laser passing hole (not shown) that does not correspond to the soldering portion may be used instead of the alignment mark. If the material of the buffer substrate 50 is transparent to the laser L, the laser passing hole (not shown) may not be formed.

A temporary adhesive portion 55 may be formed on one surface of the buffer substrate 50. Until the mask 100 is adhered to the frame 200, the temporary adhesive portion 55 can temporarily adhere the mask 100 (or the mask metal film 110) to one surface of the buffer substrate 50 so as to be supported on the buffer substrate 50.

As the temporary adhesive portion 55, an adhesive or an adhesive sheet that can be separated by heating, an adhesive or an adhesive sheet that can be separated by UV (ultraviolet) irradiation can be used.

As an example, a liquid wax may be used as the temporary adhesive portion 55. The liquid wax can be the same as the wax used in the polishing step of the wafer or the like, and its type is not particularly limited. The liquid wax may contain a substance such as acrylic resin, vinyl acetate, nylon, and various polymers, and a solvent, and is a resin component mainly used for controlling the adhesive force, impact resistance, and the like regarding the holding force. As an example, SKYLIQUID ABR-4016 can be used as the temporary adhesive portion 55, which contains acrylonitrile butadiene rubber (ABR) as a resin component and n-propanol as a solvent component. The liquid wax may be formed on the temporary adhesive portion 55 using a spin coating method.

As a temporary adhesion portion 55 of liquid wax, the viscosity decreases at a temperature higher than 85 ° C to 100 ° C, and the viscosity increases at a temperature lower than 85 ° C. It can be partially solidified like a solid, thereby enabling the mask metal film 110 to be cured. 'And the buffer substrate 50 are fixed and bonded together.

Then, referring to FIG. 5 (b), the metal film 110 ′ may be adhered on the buffer substrate 50. After the liquid wax is heated to 85 ° C. or higher, the mask metal film 110 ′ is brought into contact with the buffer substrate 50, and then the mask metal film 110 and the buffer substrate 50 are passed between the two rollers, so that adhesion can be performed.

According to an embodiment, baking is performed on the buffer substrate 50 at about 120 ° C. for 60 seconds to vaporize the solvent of the temporary bonding portion 55, and a mask metal film lamination step can be directly performed. The lamination may be performed by loading a mask metal film 110 ′ on a buffer substrate 50 having a temporary adhesive portion 55 formed on a surface thereof, and passing the mask metal film 110 ′ between an upper roll at approximately 100 ° C. and a lower roll at approximately 0 ° C. As a result, the mask metal film 110 ′ can be in contact with the buffer substrate 50 through the temporary adhesive portion 55.

FIG. 8 is an enlarged cross-sectional schematic view showing a temporary adhesive portion 55 according to an embodiment of the present invention. As another example, a thermal release tape may be used as the temporary adhesive portion 55. A core film 56 such as a PET film is disposed in the middle of the thermal release tape, and thermal release adhesive layers 57a and 57b are disposed on both surfaces of the core film 56. A release film may be disposed on the outer frame of the adhesive layers 57a and 57b. The shape of the release films 58a and 58b. The temperature at which the adhesive layers 57 a and 57 b disposed on both surfaces of the core film 56 peel off from each other may be different.

According to an embodiment, in a state where the release film / release film 58a, 58b is removed, the lower surface (second adhesive layer 57b) of the thermal release tape is adhered to the buffer substrate 50, and the upper surface (first adhesive layer) of the thermal release tape 57a) may be adhered to the mask metal film 110 '. The temperatures at which the first adhesive layer 57a and the second adhesive layer 57b are peeled from each other are different. Therefore, when the mask 100 is separated from the buffer substrate 50 by a subsequent process, the mask 100 can be heated by applying heat for thermally peeling the first adhesive layer 57a. It is separated from the buffer substrate 50 and the temporary bonding portion 55.

Next, referring to FIG. 5 (b), one surface of the mask metal film 110 ′ can be planarized with PS. As shown in FIG. 3, the mask metal film 110 ′ made through the rolling process can be reduced in thickness (110 ′-> 110) by the planarization PS process. In addition, the mask metal film 110 produced by the electroforming process is subjected to a planarization PS process in order to control the surface characteristics and thickness.

Therefore, as shown in FIG. 5 (c), as the thickness of the mask metal film 110 ′ decreases (110 ′-> 110), the thickness of the mask metal film 110 may be formed to be about 5 μm to 20 μm.

Then, referring to (d) of FIG. 6, a patterned insulating portion 25 may be formed on the mask metal film 110. The insulating portion 25 may be formed of a photoresist material by a printing method or the like.

Next, the mask metal film 110 can be etched. A method such as dry etching, wet etching, and the like can be used without limitation, and a portion of the mask metal film 110 exposed to the gap space 26 between the insulating portions 25 as a result of the etching can be etched. The etched portion of the mask metal film 110 may constitute a mask pattern P.

Then, referring to (e) of FIG. 6, the insulating portion 25 may be removed. After the insulating portion 25 is removed, manufacturing of the mask 100 in which a plurality of mask patterns P are formed on the mask metal film 110 can be completed.

On the other hand, the mask 100 is in a state of being supported on the buffer substrate 50 by the temporary adhesive portion 55. By performing only this step, the buffer substrate 50 supporting the mask 100 is moved and the mask is adhered to the frame 200, and thus it can be used for manufacturing a frame-integrated mask (see FIG. 9). Alternatively, the mask 100 is separated from the buffer substrate 50, and the mask 100 is cut in a unit including one unit C so that the mask 100 can be used for manufacturing a frame-integrated mask. Hereinafter, it is assumed that the step of separating the mask 100 from the buffer substrate 50 is further described.

Then, referring to (f) of FIG. 6, after the mask 100 is adhered to the frame 200, the mask 100 and the buffer substrate 50 can be debonded. The separation mask 100 and the buffer substrate 50 can be heated by at least one of ET, chemical treatment CM, application of ultrasonic waves US, and application of UV to the temporary adhesive portion 55.

In more detail, as an example, when the ET is heated to a temperature higher than 85 ° C. to 100 ° C., the viscosity of the temporary adhesive portion 55 decreases and the adhesive force between the mask 100 and the buffer substrate 50 is reduced, so that the mask 100 and the buffer can be separated. Substrate 50. As another example, the CM temporary adhesive portion 55 is immersed in a chemical substance such as IPA (indole propionic acid), acetone, or ethanol to dissolve the temporary adhesive portion 55, and the mask 100 and the buffer substrate 50 can be separated by removal or the like. As another example, when ultrasonic wave US or UV is applied, the adhesive force between the mask 100 and the buffer substrate 50 becomes weak, and the mask 100 and the buffer substrate 50 can be separated.

Further, the temporary bonding portion 55 for bonding the mask 100 and the buffer substrate 50 is a TBDB bonding material (temporary bonding & debonding adhesive), so various debonding methods can be used.

As an example, a solvent debonding (Solvent Debonding) method based on chemical treatment CM can be used. As the temporary adhesive portion 55 is dissolved by the penetration of the solvent, debonding can be achieved. At this time, since the mask 100 is formed with the pattern P, the solvent can be penetrated through the mask pattern P and the interface between the mask 100 and the buffer substrate 50. Solvent debonding can be debonded at room temperature, and does not require other debonding equipment with complicated design, so it is relatively economical compared with other debonding methods.

As another example, a heat debonding method based on heated ET may be used. Decomposition of the temporary adhesive portion 55 is guided by high-temperature heat, and when the adhesive force between the mask 100 and the buffer substrate 50 is reduced, it can be separated in the vertical direction or the left-right direction.

As another example, a peelable adhesive debonding method based on heating ET, UV application, or the like can be used. When the temporary adhesive portion 55 is a thermal release tape, the adhesive can be removed by a release adhesive debonding method, which does not require high-temperature heat treatment and expensive heat treatment equipment like the thermal debonding method, and the process is relatively simple.

As another example, a room temperature debonding method based on chemical treatment of CM, application of ultrasound US, application of UV, etc. may be used. When a part (center portion) of the mask 100 or the buffer substrate 50 can be subjected to a non-sticky process, the temporary adhesive portion 55 can only be adhered to the edge portion. In addition, during the debonding, the solvent penetrates into the edge portion, and the debonding can be achieved by dissolving the temporary bonding portion 55. During the bonding and debonding, the method does not cause direct loss in the remaining parts except the edge area of the mask 100 and the buffer substrate 50 or does not cause defects due to the residue of the bonding material during debonding. . In addition, unlike the thermal debonding method, a high-temperature heat treatment process is not required during debonding, so the process cost can be saved relatively.

Then, referring to (g) of FIG. 7, separation of the mask 100 and the buffer substrate 55 is completed, so that the manufacture of the mask 100 in which the plurality of mask patterns P are formed can be completed.

The mask 100 may be a large-size mask (FIG. 7 (h1)) in which a plurality of mask units C are formed, or may be a mask (FIG. 7 (h2)) in which one mask unit C is formed. The mask 100 may include one or more mask units C on which a plurality of mask patterns P are formed, and a dummy portion (DM) located around the mask units C. As described above, the mask 100 can be made from a metal sheet through a rolling process, electroforming, or the like. The dummy portion DM corresponds to a portion of the mask film 110 (mask metal film 110) other than the cell C, and may include only the mask film 110 or a mask formed with a predetermined dummy portion pattern similar in shape to the mask pattern P.模 膜 110。 The film 110.

The width of the mask pattern P may be less than 40 μm, and the thickness of the mask 100 may be about 5 to 20 μm. The frame 200 has a plurality of mask unit regions CR (CR11 to CR56), and therefore may include a plurality of masks 100, and the mask units C (C11 to C56) of the plurality of masks correspond to the respective mask unit regions CR. (CR11 ~ CR56).

FIG. 9 is a front view (FIG. 9 (a)) and a side cross-sectional view (FIG. 9 (b)) showing a frame-integrated mask according to an embodiment of the present invention. FIG. 10 is a view showing a frame-integrated mask according to an embodiment of the present invention. A front view (FIG. 10 (a)) and a side cross-sectional view (FIG. 10 (b)) of the frame according to the embodiment.

9 and 10, the frame-integrated mask may include a plurality of masks 100 and a frame 200. In other words, each mask 100 is individually adhered to the frame 200. Here, it is assumed that the mask 100 uses the mask 100 in which one mask unit C is formed as shown in (h2) of FIG. 7. In the following, for convenience of explanation, a quadrangular mask 100 is used as an example for explanation. Before the mask 100 is adhered to the frame 200, the mask 100 may have a stripe mask shape with protrusions on both sides for clamping. After the frame 200, the protruding portion can be removed.

Each mask 100 is formed with a plurality of mask patterns P, and one mask 100 may be formed with one cell C. One mask unit C may correspond to one display of a smartphone or the like.

The mask 100 may be an invar with a thermal expansion coefficient of about 1.0 × 10 ⁻⁶ / ° C. or a super invar material of about 1.0 × 10 ⁻⁷ / ° C. Since the thermal expansion coefficient of the mask 100 of this material is very low, the possibility of deformation of the pattern shape of the mask due to thermal energy is small, and it can be used as a FMM and a shadow mask in manufacturing a high-resolution OLED. In addition, in consideration of a recently developed technology for performing a pixel deposition process in a range with a small temperature change value, the mask 100 may also be made of materials such as nickel (Ni), nickel-cobalt (Ni-Co), which have a slightly larger thermal expansion coefficient. .

When a metal sheet manufactured by a rolling process is used, the thickness is thicker than that of a plating film formed by electroforming, and thus a further planarization PS process may be required. However, since the thermal expansion coefficient CTE is low, no other process is required. Heat treatment process, and strong corrosion resistance.

On the other hand, it is not necessary to use a metal sheet produced by a rolling process, and a metal sheet produced by electroforming may be used. In this case, the thermal expansion step can be performed to reduce the thermal expansion coefficient of the electroformed sheet.

The frame 200 may be formed to adhere a plurality of masks 100. Including the outermost edge, the frame 200 may include a plurality of corners formed in a first direction (for example, a lateral direction) and a second direction (for example, a vertical direction). Such a plurality of corners may divide an area of the mask 200 to be bonded on the frame 200.

The frame 200 may include an edge frame portion 210 having a substantially rectangular shape and a rectangular frame shape. The inside of the edge frame portion 210 may be a hollow shape. That is, the edge frame portion 210 may include a hollow region R. The frame 200 may be formed of a metallic material such as Invar, Super Invar, Aluminum, Titanium. In consideration of thermal deformation, it is preferably made of Invar, Super Invar, Nickel, Nickel-Cobalt having the same thermal expansion coefficient as the mask And other materials, and these materials can be applied to all the edge frame portions 210 and the mask unit sheet portion 220 which are the constituent elements of the frame 200.

In addition, the frame 200 is provided with a plurality of mask unit regions CR, and may include a mask unit sheet portion 220 connected to the edge frame portion 210. The mask unit sheet portion 220 may be formed by rolling in the same manner as the mask 100, or may be formed by another film forming step such as electroforming. In addition, the mask unit sheet portion 220 may be connected to the edge frame portion 210 after forming a plurality of mask unit regions CR on a planar sheet by laser scribing, etching, or the like. Alternatively, the mask unit sheet portion 220 may connect a planar sheet to the edge frame portion 210 and then form a plurality of mask unit regions CR by laser scribing, etching, or the like.

The mask unit sheet portion 220 may include an edge sheet portion 221 and at least one of a first grid sheet portion 223 and a second grid sheet portion 225. The edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225 refer to respective portions divided on the same sheet, and they are formed as one body with each other.

The edge sheet portion 221 may be substantially connected to the edge frame portion 210. Therefore, the edge sheet portion 221 may have a substantially quadrangular shape or a square shape corresponding to the edge frame portion 210.

In addition, the first grid sheet portion 223 may be formed to extend in a first direction (lateral direction). The first grid sheet portion 223 is formed in a linear form, and both ends thereof may be connected to the edge sheet portion 221. When the mask unit sheet portion 220 includes a plurality of first grid sheet portions 223, each of the first grid sheet portions 223 preferably has the same pitch.

In addition, further, the second grid sheet portion 225 may be formed to extend along the second direction (vertical), the second grid sheet portion 225 is formed in a linear form, and both ends thereof may be connected to the edge sheet portion 221 . The first grid sheet portion 223 and the second grid sheet portion 225 may cross each other perpendicularly. When the mask unit sheet portion 220 includes a plurality of second grid sheet portions 225, each of the second grid sheet portions 225 preferably has the same pitch.

On the other hand, depending on the size of the mask unit C, the pitch between the first grid sheet portion 223 and the pitch between the second grid sheet portion 225 may be the same or different.

Although the first grid sheet portion 223 and the second grid sheet portion 225 have a thin thickness in the form of a thin film, the shape of a cross section perpendicular to the length direction may be a rectangular shape such as a rectangle, a parallelogram, a triangle, or the like. Part of the sides and corners can form a circle. The cross-sectional shape can be adjusted during laser scribing and etching.

The thickness of the edge frame portion 210 may be larger than the thickness of the mask unit sheet portion 220. Since the edge frame portion 210 is responsible for the overall rigidity of the frame 200, it can be formed in a thickness of several mm to several tens of cm.

The mask unit sheet portion 220 is actually difficult to manufacture a thick sheet, and if it is too thick, the organic matter source 600 (see FIG. 16) may block the path through the mask 100 during the OLED pixel deposition process. Conversely, if it is too thin, it may be difficult to ensure rigidity sufficient to support the mask 100. Therefore, the mask unit sheet portion 220 is preferably thinner than the edge frame portion 210 but thicker than the mask 100. The thickness of the mask unit sheet portion 220 may be about 0.1 mm to 1 mm. In addition, the width of the first grid sheet portion 223 and the second grid sheet portion 225 may be about 1 to 5 mm.

In the planar sheet, in addition to the area occupied by the edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225, a plurality of mask unit regions CR (CR11 to CR56) can be provided. . From another perspective, the mask unit region CR may refer to the hollow region R of the edge frame portion 210, except for the edge sheet portion 221, the first grid sheet portion 223, and the second grid sheet portion 225. A blank area outside the occupied area.

As the cell C of the mask 100 corresponds to the mask cell region CR, it can actually be used as a channel for depositing pixels of the OLED through the mask pattern P. As described above, one mask unit C corresponds to one display such as a smartphone. A mask 100 may be formed with a mask pattern P for forming a unit C. Alternatively, a mask 100 includes multiple cells C and each cell C can correspond to each cell region CR of the frame 200. However, in order to accurately align the mask 100, a large area mask 100 needs to be avoided. Small area mask 100. Alternatively, one mask 100 having a plurality of cells C may correspond to one cell region CR of the mask 200. At this time, in order to accurately align, it is considered that the mask 100 having 2-3 cells C corresponds to one cell region CR of the mask 200.

The mask 200 includes a plurality of mask cell regions CR, and each mask 100 can be bonded to each mask cell C corresponding to the mask cell region CR. The mask unit C corresponds to the mask unit region CR of the frame 200, and a part or all of the dummy portion may be adhered to the frame 200 (the mask unit sheet portion 220). Thus, the mask 100 and the frame 200 may form an integrated structure.

On the other hand, according to another embodiment, the frame is not manufactured in such a manner that the mask unit sheet portion 220 is adhered to the edge frame portion 210, but may be directly formed with the edge frame using the hollow region R portion of the edge frame portion 210. The portion 210 becomes a frame of an integrated grid frame (corresponding to the grid sheet portions 223 and 225). The frame in this form also includes at least one mask unit region CR, and the mask 100 can correspond to the mask unit region CR to manufacture a frame-integrated mask.

The mask 100 of FIG. 9 and FIG. 10 includes one unit C, and therefore has a short length, so that the degree of distortion of PPA (pixel position accuracy) can be reduced. Assuming that the length of the mask 10 including a plurality of cells C1 to C6,... Is 1 m, and a PPA error of 10 μm occurs in the total length of 1 m, the mask 100 of the present invention may decrease with the relative length (equivalent As the number of cells C decreases), the above error range becomes 1 / n. For example, if the length of the mask 100 of the present invention is 100 mm, it has a length reduced from 1 m to 1/10 of the existing mask 10, so a PPA error of 1 μm occurs in the total length of 100 mm, which significantly reduces the alignment error.

On the other hand, the mask 100 includes a plurality of cells C, and even if each cell C corresponds to each cell region CR of the frame 200 within a range where the alignment error is minimized, the mask 100 can be more compatible with the frame 200. Each mask cell region CR corresponds. Alternatively, the mask 100 having a plurality of cells C may correspond to one mask cell region CR. In this case, it is also considered that the mask 100 is provided with as few cells C as possible based on the alignment process time and productivity.

In the present invention, since it is only necessary to make one cell C of the mask 100 correspond and confirm the alignment state, it is compared with the existing method of matching multiple cells C (C1 to C6) at the same time and requiring confirmation of all alignment states. , Can significantly reduce manufacturing time.

That is, the manufacturing method of the frame-integrated mask of the present invention can significantly shorten the time compared with the conventional method. The conventional method is to make each of the cells C11 to C16 included in the six masks 100 and one cell region CR11 to CR16 respectively Correspond to and confirm the 6 processes of each alignment state, and match 6 units C1 ~ C6 at the same time, and all the confirmations need to confirm the alignment states of 6 units C1 ~ C6.

In addition, in the method for manufacturing a frame-integrated mask of the present invention, the yield of the product during the 30 times in which 30 masks 100 correspond to and align with 30 unit regions CR (CR11 to CR56) can be It is significantly higher than the output of the existing product during the 5 times of matching and aligning 5 masks including 6 units C1 to C6 with the frame. Since the existing method of aligning the six cells C1 to C6 in the area corresponding to the six cells C at a time is a significantly tedious and difficult operation, the product yield is low.

FIG. 11 is a schematic diagram showing an OLED pixel deposition apparatus 1000 using frame-integrated masks 100 and 200 according to an embodiment of the present invention.

Referring to FIG. 11, the OLED pixel deposition apparatus 1000 includes: a magnetic plate 300 that houses a magnet 310 and is arranged with cooling water pipes 350; a deposition source supply unit 500 that supplies an organic material raw material 600 from a lower portion of the magnetic plate 300.

A target substrate 900 such as glass for depositing an organic material source 600 may be interposed between the magnetic plate 300 and the deposition source deposition portion 500. The target substrate 900 may be provided with a frame-integrated mask 100 or 200 (or FMM) in which the organic substance source 600 is deposited in different pixels in a close or very close manner. The magnet 310 can generate a magnetic field, and can be closely attached to the target substrate 900 through the magnetic field.

The deposition source supply unit 500 can go back and forth to the left and right paths to supply the organic substance source 600, and the organic substance source 600 supplied by the deposition source supply unit 500 can be adhered to one side of the target substrate 900 through a pattern P formed on the frame-integrated masks 100 and 200. . The organic matter source 600 deposited after passing through the pattern P of the frame-integrated masks 100 and 200 can be used as the pixel 700 of the OLED.

In order to prevent uneven deposition of the pixels 700 due to a shadow effect, the pattern of the frame-integrated masks 100 and 200 may be formed S (or formed with an adhesive tape image S) obliquely. The organic matter source 600 passing the pattern in the diagonal direction along the inclined surface can also contribute to the formation of the pixels 700, and therefore, the pixels 700 can be uniformly deposited throughout the thickness.

At a first temperature higher than the temperature of the pixel deposition process, the mask 100 is adhered and fixed to the frame 200, so even if it is raised to the temperature used for the pixel deposition process, it has little effect on the position of the mask pattern P. The mask 100 The PPA between the adjacent mask 100 can be kept to not more than 3 μm.

As described above, the present invention has illustrated and described preferred embodiments, but is not limited to the above embodiments, and those skilled in the art can make various modifications and changes without departing from the spirit of the present invention. Such deformations and changes fall within the scope of the present invention and the attached patent application.

6‧‧‧OLED pixels

10, 10'‧‧‧ Mask

13‧‧‧Patterned

14‧‧‧ formed obliquely

21‧‧‧ conductive substrate

25‧‧‧Insulation Department

26‧‧‧ Gap Space

50‧‧‧ buffer substrate

55‧‧‧Temporary Adhesive Section

56‧‧‧ core film

57a‧‧‧first adhesive layer

57b‧‧‧Second adhesive layer

58a, 58b ‧‧‧ peeling film / release film

100‧‧‧Mask

110‧‧‧plating film, mask film, mask metal film

110'‧‧‧Mask metal film

200, 1000‧‧‧OLED pixel deposition device

210‧‧‧Edge Frame Department

220‧‧‧Mask unit sheet department

221‧‧‧Edge Sheet Department

223‧‧‧First grid sheet department

225‧‧‧Second Grid Sheet Department

300‧‧‧ Magnetic plate

310‧‧‧Magnet

350‧‧‧ cooling water pipe

500‧‧‧ buffer substrate

600‧‧‧ Organic Source

700‧‧‧ pixels

900‧‧‧ target substrate

C‧‧‧unit, mask unit

CM‧‧‧Chemical treatment

CR‧‧‧Mask unit area

DM‧‧‧Virtual Department, Mask Virtual Department

ET‧‧‧Heating

P‧‧‧mask pattern; pixel pattern

PS‧‧‧ Surface flattening

US‧‧‧ Applying Ultrasound

UV‧‧‧Apply UV

R _a ‧‧‧ surface roughness

T1, T2‧‧‧thickness

FIG. 1 is a schematic diagram showing a conventional OLED pixel deposition mask.

FIG. 2 is a schematic view showing a conventional mask for forming a high-resolution OLED.

3 to 7 are schematic views showing a manufacturing process of a mask according to an embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional schematic view showing a temporary adhesive portion according to an embodiment of the present invention.

9 is a front view and a side sectional view showing a frame-integrated mask according to an embodiment of the present invention.

10 is a front view and a side cross-sectional view showing a frame according to an embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating an OLED pixel deposition device using a frame-integrated mask according to an embodiment of the present invention.

Claims (20)

A manufacturing method of a mask for manufacturing a mask for forming an OLED pixel, which is characterized in that it includes the following steps: (A) providing a mask metal film; (B) bonding the mask metal film on a buffer substrate having a temporary bonding portion formed on the surface thereof; (C) forming a mask pattern on the mask metal film; (D) separating the mask metal film on which the mask pattern is formed from the buffer substrate. The method for manufacturing a mask according to claim 1, wherein The mask metal film is formed by rolling or electroforming. The method for manufacturing a mask according to claim 1, wherein Between step (b) and step (c), the method further includes a step of reducing a thickness of the mask metal film adhered to the buffer substrate. The method for manufacturing a mask according to claim 2, wherein When the mask metal film is formed by the electroforming, the step (a) includes the following steps: (A1) forming the mask metal film on at least one surface of a conductive single crystal substrate; and (A2) The mask metal film is separated from the conductive single crystal substrate. The method for manufacturing a mask according to claim 4, wherein The step (a1) and the step (a2) further include a step of performing a heat treatment on the mask metal film. The method for manufacturing a mask according to claim 1, wherein The temporary adhesive portion is an adhesive or an adhesive sheet that can be separated by heating, an adhesive or an adhesive sheet that can be separated by UV irradiation. The method for manufacturing a mask according to claim 6, wherein The temporary adhesive portion is a liquid wax or a thermal peeling tape. The method for manufacturing a mask according to claim 7, wherein The liquid wax fixes and adheres the mask metal film and the buffer substrate at a temperature lower than 85 ° C. The method for manufacturing a mask according to claim 8, wherein In the step (b), after the liquid wax is heated to 85 ° C or higher, the mask metal film is brought into contact with the buffer substrate, and then the mask metal film and the buffer substrate are passed through two Between the rollers for bonding. The method for manufacturing a mask according to claim 1, wherein In the step (b), before the mask metal film is adhered, a laser passing hole is formed in a portion of the buffer substrate corresponding to a soldered portion of the mask. The method for manufacturing a mask according to claim 1, wherein The step (c) includes the following steps: (C1) forming a patterned insulating portion on the mask metal film; (C2) etching the portion of the mask metal film exposed from between the insulating portions to form the mask pattern; and (C3) Remove the insulating portion. The method for manufacturing a mask according to claim 1, wherein In the step (d), the temporary bonding portion is subjected to at least one of heating, chemical treatment, application of ultrasonic waves, and application of UV to separate the mask metal film and the buffer substrate. The method for manufacturing a mask according to claim 12, wherein In step (d), any one of solvent debonding, thermal debonding, peelable adhesive debonding, and room temperature debonding is performed. A mask support buffer substrate for supporting a mask for forming an OLED pixel, which is characterized in that: Buffer substrate A temporary adhesive portion formed on the buffer substrate; and The mask is formed with a mask pattern, and is adhered to the buffer substrate through the temporary adhesive portion. The mask supporting buffer substrate according to claim 14, wherein The thickness of the mask metal film is 5 μm to 20 μm. The mask supporting buffer substrate according to claim 14, wherein The temporary adhesive portion is an adhesive or an adhesive sheet that can be separated by heating, an adhesive or an adhesive sheet that can be separated by UV irradiation. The mask supporting buffer substrate according to claim 14, wherein The buffer substrate includes any one of wafer, glass, silicon dioxide, heat-resistant glass, quartz, tri-alumina, borosilicate glass, and zirconia. The mask supporting buffer substrate according to claim 14, wherein Laser buffer holes are formed in portions of the buffer substrate and the temporary adhesive portions corresponding to the soldered portions of the mask. The mask supporting buffer substrate according to claim 14, wherein The mask includes one or more mask units formed with a plurality of the mask patterns. A manufacturing method of a mask supporting buffer substrate is used for manufacturing a buffer substrate. The buffer substrate supports a mask for forming an OLED pixel so as to correspond to a frame. The buffer substrate includes the following steps: (A) providing a mask metal film; (B) bonding the mask metal film on a buffer substrate having a temporary bonding portion formed on the surface; and (C) forming a mask pattern on the mask metal film to manufacture a mask.