KR102028639B1 - Method of mask, buffer substrate for supporting mask and producing method thereof - Google Patents

Abstract

The present invention relates to a mask support buffer substrate, a method for manufacturing the same, and a method for manufacturing a frame-integrated mask. According to the present invention, the method for manufacturing a mask support buffer substrate, as a method of manufacturing a buffer substrate (50) which supports an OLED pixel forming mask (100) and corresponds to a frame (200), comprises the steps of: (a) providing a mask metal film (110); (b) adhering the mask metal film (110) on the buffer substrate (50) having a temporary adhesive part (55) formed on one surface thereof; (c) forming a mask pattern (P) on the mask metal film (110); and (d) separating the mask metal film (110) on which the mask pattern (P) is formed from the buffer substrate (50).

Description

Mask manufacturing method, mask supporting buffer substrate and manufacturing method thereof {METHOD OF MASK, BUFFER SUBSTRATE FOR SUPPORTING MASK AND PRODUCING METHOD THEREOF}

A method of manufacturing a mask, a mask support buffer substrate, and a method of manufacturing the same. More specifically, the present invention relates to a method of manufacturing a mask, a mask supporting buffer substrate, and a method of manufacturing the mask, which can stably form a pattern on the mask and stably support and move without deformation of the mask.

As a technique for forming pixels in an OLED manufacturing process, a fine metal mask (FMM) method is used in which a thin metal mask is adhered to a substrate to deposit an organic material at a desired position.

In the case of ultra-high-definition OLED, QHD image quality is 500 ~ 600 pixel per inch (PPI), and the pixel size is about 30 ~ 50㎛. It has a resolution of. As such, considering the pixel size of the ultra-high-definition OLED, the alignment error between each cell should be reduced to several μm, and the error beyond this may lead to product failure, resulting in very low yield. Therefore, there is a need for development of a technique for preventing deformation, such as knocking or twisting of a mask and making alignment clear, a technique for fixing a mask to a frame, and the like.

Accordingly, an object of the present invention is to provide a mask manufacturing method capable of stably forming a pattern on a mask, which is devised to solve the above-mentioned problems of the prior art.

Another object of the present invention is to provide a mask support buffer substrate capable of stably supporting and moving a mask without deformation and a method of manufacturing the same.

The above object of the present invention is a method of manufacturing a mask for forming an OLED pixel, comprising the steps of: (a) providing a mask metal film; (b) adhering a mask metal film on a buffer substrate having a temporary adhesive portion formed on one surface thereof; (c) forming a mask pattern on the mask metal film; and (d) separating the mask metal film on which the mask pattern is formed from the buffer substrate.

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

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

The thickness reduction of the mask metal film may be performed by any one of chemical mechanical polishing (CMP), chemical wet etching, and dry etching.

When the mask metal film is produced by electroplating, the step (a) may include: (a1) forming a mask metal film on at least one surface of the conductive single crystal substrate; And (a2) separating the mask metal film from the conductive single crystal substrate.

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

The temporary adhesive part may be an adhesive or adhesive sheet that can be separated by applying heat, and an adhesive or adhesive sheet that can be separated by UV irradiation.

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

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

In step (b), 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 the rollers to perform adhesion.

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

The through-holes of the laser can be formed through the portion of the temporary bonding portion on the buffer substrate.

(c) step (c1) forming a patterned insulating portion on the mask metal film; (c2) etching a portion of the mask metal film exposed between the insulating parts to form a mask pattern; And (c3) removing the insulation.

After the step (c), the mask metal film may include a plurality of mask cells in which a plurality of mask patterns are formed.

After the step (c), the mask metal film may include one mask cell in which a plurality of mask patterns are formed.

Step (d) may be performed to separate the mask metal film and the buffer substrate by performing at least one of heat application, chemical treatment, ultrasonic application, and UV application to the temporary bonding portion.

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

The mask may be a material of any one of invar, super invar, nickel, and nickel-cobalt.

In addition, the above object of the present invention is a buffer substrate for supporting a mask for forming an OLED pixel, comprising: a buffer substrate; A temporary adhesive portion formed on the buffer substrate; And a mask bonded onto the buffer substrate via the temporary bonding portion and including a mask having a mask pattern formed thereon.

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

The temporary adhesive part may be an adhesive or adhesive sheet that can be separated by applying heat, and an adhesive or adhesive sheet that can be separated by UV irradiation.

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

The buffer substrate may include any one of a wafer, glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia. Can be.

Laser through holes may be formed in portions of the buffer substrate and the temporary bonding portions corresponding to the welding portions of the mask.

The mask may include a plurality of mask cells in which a plurality of mask patterns are formed.

The mask may include one mask cell in which a plurality of mask patterns are formed.

The mask may be composed of a metal sheet manufactured by a rolling process or an electroforming process.

In addition, the above object of the present invention is a method of manufacturing a buffer substrate (buffer substrate) for supporting a mask for forming an OLED pixel to correspond to a frame, comprising the steps of: (a) providing a mask metal film; (b) adhering a mask metal film on a buffer substrate having a temporary adhesive portion formed on one surface thereof; And (c) forming a mask pattern on the mask metal film to produce a mask.

According to the present invention configured as described above, there is an effect that can stably form a pattern on the mask.

In addition, according to the present invention, there is an effect capable of stably supporting and moving the mask without deformation.

1 is a schematic view showing a conventional mask for OLED pixel deposition.
2 is a schematic diagram showing a mask for forming a conventional high resolution OLED.
3 to 7 are schematic views showing a manufacturing process of a mask according to an embodiment of the present invention.
Figure 8 is an enlarged cross-sectional schematic diagram showing a temporary adhesive portion according to an embodiment of the present invention.
9 is a front and side cross-sectional view showing a frame-integrated mask according to an embodiment of the present invention.
10 is a front and side cross-sectional view showing a frame according to an embodiment of the present invention.
11 is a schematic diagram illustrating an OLED pixel deposition apparatus using a frame-integrated mask according to an embodiment of the present invention.

DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be embodied in other embodiments without departing from the spirit and scope of the invention with respect to one embodiment. In addition, it is to 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 invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. In the drawings, like reference numerals refer to the same or similar functions throughout the several aspects, and length, area, thickness, and the like may be exaggerated for convenience.

DETAILED DESCRIPTION Hereinafter, exemplary 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.

1 is a schematic diagram showing a conventional mask for depositing OLED pixels 10.

Referring to FIG. 1, the conventional mask 10 may be manufactured in a stick type or a plate type. The mask 10 shown in FIG. 1A is a stick type mask, and both sides of the stick may be welded and fixed to the OLED pixel deposition frame. The mask 10 shown in FIG. 1B is a plate-type mask, and may be used in a large area pixel forming process, and the edge of the plate is formed by the OLED pixel deposition frame 200 [see FIG. 11]. It can be used by fixing to welding. (C) is an enlarged side sectional view of A-A 'part.

A plurality of display cells C are provided in the body (or mask film 11) of the mask 10. One cell C corresponds to one display such as a smartphone. In the cell C, a pixel pattern P (mask pattern P) is formed so as to correspond to each pixel of the display. When the cell C is enlarged, a plurality of pixel patterns P corresponding to R, G, and B appear. For example, the pixel pattern P is formed in the cell C to have a resolution of 70 × 140. That is, a large number of pixel patterns P may be clustered to form one cell C, and a plurality of cells C may be formed in the mask 10.

The mask patterns P may have an inclined side portion and a taper shape. It is preferable that the mask pattern P has a substantially tapered shape having a shape that becomes wider or narrower from the top to the bottom, and the upper surface of the mask 100 is the target substrate 900 (see FIG. 11). It is more preferable that the mask pattern P has a shape that becomes wider in width from the top to the bottom because it is in close contact with

2 is a schematic diagram showing a mask for forming a conventional high resolution OLED.

In order to implement a high-resolution OLED, the size of the pattern is decreasing, and the thickness of the mask metal film used for this needs to be thinned. As shown in FIG. 2A, in order to implement the OLED pixel 6 having a high resolution, the pixel spacing and the pixel size of the mask 10 'must be reduced (PD-> PD'). Further, in order to prevent the OLED pixel 6 from being unevenly deposited due to the shadow effect, it is necessary to form the pattern 14 of the mask 10 'to be inclined. However, in the process of forming the inclined pattern 14 on the thick mask 10 'with a thickness T1 of about 30 to 50 µm, patterning 13 suitable for the minute pixel interval PD' and pixel size is formed. Since it is difficult to do this, it becomes a cause of a bad yield in a machining process. In other words, in order to form the pattern 14 to be inclined with a fine pixel interval PD ', a thin mask 10' must be used.

In particular, for high resolution of the UHD level, as shown in (b) of FIG. 2, fine patterning may be performed only by using a thin mask 10 'having a thickness T2 of about 20 μm or less. In addition, the use of a thin mask 10 ′ having a thickness T2 of about 10 μm may be considered for ultra high resolution of UHD or higher.

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 100 by manufacturing the mask metal film 110 'and supporting it on the buffer substrate 50 will be described.

3 is a schematic diagram illustrating a process of manufacturing a mask metal film by a rolling method according to an embodiment of the present invention. 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, the mask metal film 110 may be prepared. In an embodiment, the mask metal film 110 may be prepared by a rolling method.

Referring to FIG. 3A, the metal sheet generated by the rolling process may be used as the mask metal film 110 ′. The metal sheet manufactured by the rolling process may have a thickness of several tens to several hundred micrometers in the manufacturing process. As described above in FIG. 2, fine patterning may be performed by using a thin mask metal film 110 having a thickness of about 20 μm or less for UHD high resolution, and a thickness of about 10 μm for ultra high resolution of UHD or more. A thin mask metal film 110 having a must be used. However, since the mask metal film 110 ′ produced by the rolling process has a thickness of about 25 to 500 μm, the thickness of the mask metal film 110 ′ needs to be thinner.

Therefore, a process of planarizing (PS) one surface of the mask metal film 110 ′ may be further performed. Here, the planarization PS means that the thickness of the mask metal film 110 ′ is reduced by thinning one surface (upper surface) of the mask metal film 110 ′ and simultaneously removing a portion of the mask metal film 110 ′. Planarization (PS) may be performed by a chemical mechanical polishing (CMP) method, and known CMP methods may be used without limitation. In addition, the thickness of the mask metal layer 110 ′ may be reduced by chemical wet etching or dry etching. In addition, a process capable of flattening to thin the thickness of the mask metal film 110 ′ may be used without limitation.

In the process of performing a flattening (PS), in the CMP process, For example, a mask, a metal film (110 '), the surface roughness of the top surface (R _a) can be controlled. Preferably, mirroring may proceed with further reduction in surface roughness. Alternatively, another example, may be after performing a chemical wet etch or dry etch planarization process (PS) advances to, in addition to the polishing process, such as a separate CMP process after reducing the surface roughness (R _a).

As such, the thickness of the mask metal film 110 ′ may be made thinner than about 50 μm. Accordingly, the thickness of the mask metal film 110 may be about 2 μm to about 50 μm, and more preferably about 5 μm to about 20 μm. However, it is not necessarily limited thereto.

Referring to FIG. 3B, as in FIG. 3A, the mask metal film 110 may be manufactured by reducing the thickness of the mask metal film 110 ′ manufactured by the rolling process. However, the thickness of the mask metal film 110 ′ may be reduced by performing a planarization (PS) process in a state where the mask metal film 110 ′ is bonded to the buffer substrate 50 through the temporary adhesion part 55.

In another embodiment, the mask metal film 110 may be prepared by electroplating.

Referring to FIG. 4A, the conductive substrate 21 is prepared. In order to perform electroforming, the substrate 21 of the mother plate may be a conductive material. The mother plate can be used as a cathode electrode in electroplating.

As the conductive material, in the case of metal, metal oxides may be generated on the surface, impurities may be introduced during the metal manufacturing process, and in the case of the polycrystalline silicon substrate, inclusions or grain boundaries may exist, and the conductive polymer may be present. In the case of a base material, it is highly likely to contain an impurity, and strength. Acid resistance may be weak. Elements that interfere with the uniform formation of an electric field on the surface of the substrate (or negative electrode body), such as metal oxides, impurities, inclusions, grain boundaries, etc., are referred to as "defects." Due to the defect, a uniform electric field may not be applied to the cathode body of the above-described material, so that a part of the plating film 110 (or the mask metal film 110) may be unevenly formed.

Non-uniformity of the plating film and the plating film pattern (mask pattern P) may adversely affect the formation of the pixel in implementing a UHD-class or higher definition pixel. For example, QHD image quality is 500 ~ 600 pixel per inch (PPI), and the pixel size is about 30 ~ 50㎛, and 4K UHD, 8K UHD high definition is ~ 860 PPI, ~ 1600 PPI Have the same resolution. The micro display applied directly to the VR device, or the micro display used in the VR device, aims at an ultra-high quality of about 2,000 PPI or more, and the size of the pixel reaches about 5 to 10 μm. Since the pattern width of the FMM and shadow mask applied to this can be formed in a size of several to several tens of micrometers, preferably smaller than 30 micrometers, even a defect of several micrometers is large enough to occupy a large proportion of the pattern size of the mask. to be. In addition, an additional process for removing metal oxides, impurities, and the like may be performed to remove the defects in the cathode material of the material described above, and another defect such as etching of the anode material may be caused in this process. have.

Accordingly, the present invention can use a mother plate (or a negative electrode body) of a single crystal material. In particular, it is preferable that it is a single crystal silicon material. In order to have conductivity, a high concentration doping of 10 ¹⁹ / cm ³ or more may be performed on the single crystal silicon base plate. Doping may be performed on the entirety of the mother plate, or only on the surface portion of the mother plate.

On the other hand, as the single crystal material, metals such as Ti, Cu, Ag, carbon-based materials such as semiconductors such as GaN, SiC, GaAs, GaP, AlN, InN, InP, Ge, graphite, and graphene _{, CH 3 NH 3 PbCl 3,} CH 3 NH 3 PbBr 3, CH 3 NH 3 PbI 3, SrTiO 3 , etc. page containing the perovskite (perovskite) superconductor single crystalline ceramic, aircraft single crystal second heat-resistant alloy for components for such structures And the like can be used. Metal and carbon-based materials are basically conductive materials. In the case of a semiconductor material, a high concentration doping of 10 ¹⁹ / cm ³ or more may be performed to have conductivity. In the case of other materials, the conductivity may be formed by performing doping or forming oxygen vacancies. Doping may be performed on the entirety of the mother plate, or only on the surface portion of the mother plate.

Since there is no defect in the case of a single crystal material, there is an advantage in that a uniform plating film 110 may be generated due to the formation of a uniform electric field on all surfaces during electroplating. The frame-integrated masks 100 and 200 manufactured through the uniform plating layer may further improve the image quality level of the OLED pixel. In addition, since an additional process of eliminating and eliminating defects does not have to be performed, process costs are reduced and productivity is improved.

Referring back to FIG. 4A, next, the conductive substrate 21 is used as a mother plate (cathode body), and the anode body (not shown) is spaced apart on the conductive substrate 21. The plating film 110 (or the mask metal film 110) can be formed in the electroplating. The plating film 110 may be formed on the exposed top and side surfaces of the conductive substrate 21 facing the anode and capable of acting on an electric field. In addition to the side surface of the conductive substrate 21, the plating film 110 may be formed even on a part of the lower surface of the conductive substrate 21.

Next, the edge of the plating film 110 may be cut (D) with a laser, or a photoresist layer may be formed on the plating film 110, and only a portion of the exposed plating film 110 may be etched and removed (D). Can be. Accordingly, as shown in FIG. 4B, the plating film 110 can be separated from the conductive substrate 21.

On the other hand, before the plating film 110 is separated from the conductive substrate 21, heat treatment (H) may be performed. In order to reduce the thermal expansion coefficient of the mask 100 and to prevent deformation due to the heat of the mask 100 and the mask pattern P, the plating film (or the base plate, the cathode body) is formed from the plated film ( Before the separation 110, characterized in that the heat treatment (H) is performed. Heat treatment may be carried out at a temperature of 300 ℃ to 800 ℃.

In general, the Invar thin plate produced by electroplating has a higher coefficient of thermal expansion as compared to the Invar thin plate produced by rolling. Thus, the thermal expansion coefficient can be lowered by performing heat treatment on the Invar thin plate. In this heat treatment, peeling, deformation, etc. may occur on the Invar thin plate. This is a phenomenon that occurs because only the Invar thin plate is heat-treated, or the Invar thin plate temporarily bonded only to the upper surface of the conductive substrate 21. However, in the present invention, since the plating film 110 is formed not only on the upper surface of the conductive substrate 21 but also on part of the side surface and the lower surface, no peeling or deformation occurs even when the heat treatment (H) is performed. In other words, since the heat treatment is performed in a state in which the conductive base material 21 and the plating film 110 are closely adhered to each other, there is an advantage in that delamination, deformation, etc. due to heat treatment can be prevented and heat treatment can be stably performed.

The thickness of the mask metal film 110 generated by the electroplating process may be thinner than the rolling process. Accordingly, although the planarization (PS) process of reducing the thickness may be omitted, the etching characteristics may vary depending on the composition of the surface layer of the plating mask metal film 110 ′ and the crystal structure / fine structure. It is necessary to control the surface characteristics and thickness through.

5 to 7 are schematic views illustrating a process of manufacturing a mask support buffer substrate by adhering a mask metal layer 110 on a buffer substrate 50 and forming a mask 100 according to an embodiment of the present invention.

Referring to FIG. 5A, a buffer substrate 50 may be provided. When the buffer substrate 500 forms the mask pattern P on the mask metal film 110, a medium for supporting the mask metal film 110 or a state in which the manufactured mask 100 is attached and supported on one surface of the buffer substrate 500 is provided. It can be moved to. One surface of the buffer substrate 50 may be flat so as to support the flat mask 100 or the mask metal film 110. The central portion 50a may correspond to the mask cell C of the mask metal film 110, and the edge portion 50b may correspond to the dummy DM of the mask metal film 110. The buffer substrate 50 may have a flat plate shape having a larger area than that of the mask metal film 110 so that the mask metal film 110 may be entirely supported.

The buffer substrate 50 may be made of a transparent material so that the vision 100 may be easily observed in the process of aligning and bonding the mask 100 to the frame 200 in a subsequent process. In addition, the laser may penetrate the transparent material. As a transparent material, materials such as glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia may be used. For example, the buffer substrate 50 may use a BOROFLOAT ^® 33 material having excellent heat resistance, chemical durability, mechanical strength, transparency, and the like in borosilicate glass. In addition, BOROFLOAT ^® 33 has a thermal expansion coefficient of about 3.3, which is advantageous in controlling the mask metal film 110 because the difference between the Invar mask metal film 110 and the thermal expansion coefficient is small.

On the other hand, one surface of the buffer substrate 50 which is in contact with the mask metal film 110 so as not to generate an air gap between the interface with the mask metal film 110 (or the mask 100) is mirrored. Can be. In consideration of this, the surface roughness Ra of one surface of the buffer substrate 50 may be 100 nm or less. In order to implement the buffer substrate 50 having the surface roughness Ra of 100 nm or less, the buffer substrate 50 may use a wafer. Since a wafer has a surface roughness Ra of about 10 nm, many products on the market, and many surface treatment processes are known, the wafer can be used as the buffer substrate 50. Since the surface roughness Ra of the buffer substrate 50 is nm scale, there is no air gap or almost no air gap, and it is easy to generate the welding bead WB by laser welding, thereby affecting the alignment error of the mask pattern P. May not give.

The buffer substrate 50 has a laser passing hole in the buffer substrate 50 so that the laser L irradiated from the upper portion of the buffer substrate 50 can reach the welding part (region to be welded) of the mask 100. Not shown) may be formed. Laser through holes (not shown) may be formed in the buffer substrate 50 to correspond to the position and the number of welds. Since a plurality of welding parts are disposed along a predetermined interval at edges or dummy DM portions of the mask 100, a plurality of laser passing holes (not shown) may also be formed along the predetermined interval to correspond thereto. For example, since a plurality of welds are disposed at both sides (left / right) of the mask 100 at a portion of the dummy DM along a predetermined interval, the laser passing hole (not shown) also has the buffer substrate 50 at both sides (left / right). A plurality may be formed along a predetermined interval. Meanwhile, a laser through hole (not shown) may be formed in a state in which the temporary adhesive part 55 is formed on the buffer substrate 50. In this case, the laser through hole (not shown) may be formed to penetrate the buffer substrate 50 and the temporary adhesive part 55.

The laser through hole (not shown) does not necessarily correspond to the position and the number of welds. For example, welding may be performed by irradiating the laser L only to a part of the laser passing holes (not shown). In addition, some of the laser passing holes (not shown) corresponding to the welding part may be used instead of the alignment mark when the mask 100 and the buffer substrate 50 are aligned. If the material of the buffer substrate 50 is transparent to the laser light, laser pass holes (not shown) may not be formed.

A temporary adhesive part 55 may be formed on one surface of the buffer substrate 50. In the temporary adhesive part 55, the mask 100 (or the mask metal film 110) is temporarily bonded to one surface of the buffer substrate 50 until the mask 100 is bonded to the frame 200. ) Can be supported.

The temporary adhesive part 55 may use an adhesive or an adhesive sheet that can be separated by applying heat, an adhesive or an adhesive sheet that can be separated by UV irradiation.

For example, the temporary adhesive part 55 may use liquid wax. The liquid wax can use the same thing as the wax used in the polishing step of a semiconductor wafer, etc., The type is not specifically limited. Liquid waxes may mainly include solvents and materials such as acrylic, vinyl acetate, nylon and various polymers as resin components for controlling adhesion, impact resistance, and the like regarding holding force. For example, the temporary adhesive part 55 may use acrylonitrile butadiene rubber (ABR) as a resin component and SKYLIQUID ABR-4016 including n-propyl alcohol as a solvent component. Liquid wax may be formed on the temporary bond 55 using spin coating.

The temporary adhesive portion 55, which is a liquid wax, has a low viscosity at temperatures higher than 85 ° C to 100 ° C, and may become viscous at a temperature lower than 85 ° C and may be partially solid, such that the mask metal film 110 'and the buffer substrate ( 50) can be fixedly bonded.

Next, referring to FIG. 5B, the mask metal film 110 ′ may be adhered to the buffer substrate 50. After the liquid wax is heated to 85 ° C. or more and the mask metal film 110 ′ is brought into contact with the buffer substrate 50, the mask metal film 110 and the buffer substrate 50 may be passed between the rollers to perform adhesion. have.

According to one embodiment, the buffer substrate 50 may be baked at about 120 ° C. for 60 seconds to vaporize the solvent of the temporary adhesive part 55, and immediately proceed to a mask metal film lamination process. have. Lamination is performed by loading the mask metal film 110 ′ on the buffer substrate 50 having the temporary adhesive part 55 formed on one surface thereof, and passing it between an upper roll of about 100 ° C. and a lower roll of about 0 ° C. can do. As a result, the mask metal film 110 ′ may be contacted on the buffer substrate 50 via the temporary adhesive part 55.

8 is an enlarged cross-sectional schematic view of the temporary bonding portion 55 according to an embodiment of the present invention. As another example, the temporary adhesive part 55 may use a thermal release tape. In the heat-peelable tape, a core film 56 such as a PET film is disposed in the center, and thermal release adhesives 57a and 57b are arranged on both surfaces of the core film 56, and the adhesive layer 57a is provided. , 57b) may be in a form in which release films / release films 58a and 58b are disposed. Here, the adhesive layers 57a and 57b disposed on both surfaces of the core film 56 may have different temperatures at which they are peeled off.

According to one embodiment, with the release film / release film 58a, 58b removed, the bottom surface (second adhesive layer 57b) of the heat release tape is adhered to the buffer substrate 50, and the The upper surface (first adhesive layer 57a) may be adhered to the mask metal film 110 '. Since the temperature at which the first adhesive layer 57a and the second adhesive layer 57b are separated from each other is different, when the buffer substrate 50 is separated from the mask 100 in a subsequent process, the first adhesive layer 57a is formed. The mask 100 may be separated from the buffer substrate 50 and the temporary adhesive part 55 by applying heat to be separated.

Subsequently, referring to FIG. 5B, one surface of the mask metal film 110 ′ may be planarized (PS). As described above with reference to FIG. 3, the mask metal film 110 ′ manufactured by the rolling process may reduce the thickness 110 ′-> 110 by a planarization (PS) process. In addition, the mask metal film 110 manufactured by the electroplating process may be performed with a planarization (PS) process to control surface characteristics and thickness.

Accordingly, as shown in FIG. 5C, as the thickness of the mask metal film 110 ′ is reduced (110 ′-> 110), the mask metal film 110 may have a thickness of about 5 μm to 20 μm. Can be.

Next, referring to FIG. 6D, 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 using a printing method or the like.

Subsequently, etching of the mask metal layer 110 may be performed. Methods such as dry etching and wet etching may be used without limitation, and a portion of the mask metal film 110 exposed to the empty space 26 between the insulating portions 25 may be etched as a result of the etching. An etched portion of the mask metal layer 110 may constitute a mask pattern P. FIG.

Next, referring to FIG. 6E, the insulation portion 25 may be removed. If the insulating part 25 is removed, the mask 100 having the plurality of mask patterns P formed on the mask metal film 110 may be completed.

On the other hand, the mask 100 is supported on the buffer substrate 50 via the temporary adhesive part 55. By proceeding only to this step, by moving the buffer substrate 50 itself supported by the mask 100 to adhere the mask 100 to the frame 200, it can be used to manufacture a frame-integrated mask (see Fig. 9). . Alternatively, the mask 100 may be separated from the buffer substrate 50, and the mask 100 may be cut in a unit including one cell C to be used for manufacturing a frame-integrated mask. Hereinafter, it is assumed that the process of separating the mask 100 from the buffer substrate 50 is further performed.

Next, referring to FIG. 6F, after the mask 100 is adhered to the frame 200, the mask 100 and the buffer substrate 50 may be debonded. Separation of the mask 100 and the buffer substrate 50 may be performed through at least one of heat application (ET), chemical treatment (CM), ultrasonic application (US), and UV application (UV) to the temporary adhesive part 55. Can be.

For example, when heat (ET) at a temperature higher than 85 ° C. to 100 ° C. is applied, the viscosity of the temporary adhesive part 55 is lowered, and the adhesion between the mask 100 and the buffer substrate 50 is weakened. 100 and the buffer substrate 50 may be separated. As another example, the mask 100 and the buffer substrate 50 may be separated by dissolving and removing the temporary adhesive part 55 by dipping (CM) the temporary adhesive part 55 in chemical substances such as IPA, acetone, and ethanol. Can be. As another example, when the ultrasonic wave (US) or the UV (UV) is applied, the adhesion between the mask 100 and the buffer substrate 50 is weakened, so that the mask 100 and the buffer substrate 50 may be separated. .

In more detail, since the temporary bonding part 55 which mediates the adhesion between the mask 100 and the buffer substrate 50 is a TBDB adhesive material (temporary bonding & debonding adhesive), various debonding methods can be used.

For example, a solvent debonding method according to chemical treatment (CM) may be used. As the temporary adhesive part 55 is dissolved by penetration of a solvent, debonding may be performed. In this case, since the pattern P is formed in the mask 100, the solvent may penetrate through the mask pattern P and the interface between the mask 100 and the buffer substrate 50. Solvent debonding has the advantage of being relatively economical as compared to other debonding methods because it can be debonded at room temperature and does not require a separate, devised complex debonding facility.

As another example, a heat debonding method according to heat application ET may be used. Debonding may be performed in the vertical direction or the left and right directions when the decomposition of the temporary adhesive part 55 is induced using high temperature heat and the adhesive force between the mask 100 and the buffer substrate 50 is reduced.

As another example, a peelable adhesive debonding method according to heat application (ET), UV application (UV), or the like may be used. When the temporary adhesive part 55 is a heat-peelable tape, debonding may be performed by a peeling adhesive debonding method, which does not require high temperature heat treatment and expensive heat treatment equipment as a thermal debonding method. Has a relatively simple advantage.

As another example, a room temperature debonding method according to chemical treatment (CM), ultrasonic application (US), UV application (UV), or the like may be used. When the non-sticky process is applied to a part (center) of the mask 100 or the buffer substrate 50, only the edge part may be adhered by the temporary adhesive part 55. In addition, during the debonding, the solvent penetrates into the edge portion, and the debonding is performed by dissolution of the entrance-adhesion part 55. In this method, the remaining portions of the mask 100 and the buffer substrate 50 except for the edges of the mask 100 and the buffer substrate 50 are not directly lost during bonding and debonding, or defects due to the adhesive material residue during debonding do not occur. There is an advantage. In addition, unlike the thermal debonding method, since the high temperature heat treatment process is not required during debonding, there is an advantage in that the process cost can be relatively reduced.

Next, referring to FIG. 7G, the separation of the mask 100 and the buffer substrate 55 may be completed, and thus manufacturing of the mask 100 having the plurality of mask patterns P may be completed.

The mask 100 may be a large mask (FIG. 7 (h1)) in which a plurality of mask cells C are formed, or may be a mask (FIG. 7 (h2)) in which one mask cell C is formed. The mask 100 may include one or a plurality of mask cells C on which a plurality of mask patterns P are formed, and a dummy DM around the mask cells C. FIG. As described above, the mask 100 may be manufactured from a metal sheet generated by a rolling process, electroplating, or the like. The dummy DM corresponds to a portion of the mask film 110 (mask metal film 110) except for the cell C, includes only the mask film 110, or a predetermined dummy in a form similar to the mask pattern P. FIG. The patterned mask layer 110 may be included.

The width of the mask pattern P may be smaller than 40 μm, and the thickness of the mask 100 may be about 5 to 20 μm. Since the frame 200 includes a plurality of mask cell regions CR: CR11 to CR56, the mask 100 having mask cells C11 to C56 corresponding to the mask cell regions CR11 to CR56, respectively. ) Can also be provided in plurality.

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, Figure 10 is in accordance with an embodiment of the present invention It is a front view (FIG. 10 (a)) and a side cross-sectional view (FIG. 10 (b)) which show a frame.

9 and 10, the frame integrated mask may include a plurality of masks 100 and one frame 200. In other words, the plurality of masks 100 are bonded to the frame 200 one by one. Here, the mask 100 is assumed to use a mask 100 in which one mask cell C shown in FIG. 7 (h2) is formed. Hereinafter, for convenience of description, the rectangular mask 100 will be described as an example. However, the masks 100 may be provided with protrusions clamped at both sides before being bonded to the frame 200. The protrusions can be removed after they are glued.

A plurality of mask patterns P may be formed in each mask 100, and one cell C may be formed in one mask 100. One mask cell C may correspond to one display such as a smartphone.

The mask 100 may be an invar having a thermal expansion coefficient of about 1.0 × 10 ⁻⁶ / ° C. and a super invar material having about 1.0 × 10 ⁻⁷ / ° C. Since the mask 100 of this material has a very low coefficient of thermal expansion, there is little possibility that the pattern shape of the mask is deformed by thermal energy, and thus, the mask 100 may be used as a fine metal mask (FMM) or a shadow mask in high-resolution OLED manufacturing. In addition, in consideration of the recent development of techniques for performing the pixel deposition process in a range where the temperature change is not large, the mask 100 has a slightly larger thermal expansion coefficient than that of nickel (Ni) and nickel-cobalt (Ni-Co). It may be a material such as).

In the case of using a metal sheet manufactured by a rolling process, a planarization (PS) process may be necessary because it is thicker in thickness than a plated film formed by electroplating, but a separate heat treatment process may be performed because the coefficient of thermal expansion (CTE) is low. It does not need to be carried out and has the advantage of strong corrosion resistance.

In addition, the metal sheet produced | generated by electroforming can also be used, without necessarily using the metal sheet | seat produced by the rolling process. In this case, the thermal expansion coefficient of the electroplating sheet may be lowered by further performing a heat treatment process.

The frame 200 is formed to bond the plurality of masks 100. The frame 200 may include various edges formed in a first direction (eg, a horizontal direction) and a second direction (eg, a vertical direction) including an outermost edge. These various corners may define the area to which the mask 100 is 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 frame frame 210 may be hollow. That is, the frame frame portion 210 may include a hollow area. The frame 200 may be made of a metal material such as Invar, Super Invar, Aluminum, Titanium, etc., and may be made of Inbar, Super Invar, Nickel, or Nickel-Cobalt having the same thermal expansion coefficient as a mask in consideration of thermal deformation. Preferably, the materials may be applied to both the edge frame portion 210 and the mask cell sheet portion 220 which are components of the frame 200.

In addition, the frame 200 may include a plurality of mask cell regions CR and may include a mask cell sheet portion 220 connected to the edge frame portion 210. Like the mask 100, the mask cell sheet part 220 may be formed by rolling, or may be formed using another film forming process such as electroplating. In addition, the mask cell sheet part 220 may be connected to the edge frame part 210 after forming a plurality of mask cell areas CR through laser scribing or etching on a flat sheet. Alternatively, the mask cell sheet unit 220 may form a plurality of mask cell regions CR through laser scribing, etching, etc. after connecting the planar sheet to the edge frame unit 210.

The mask cell sheet part 220 may include at least one of the edge sheet part 221 and the first and second grid sheet parts 223 and 225. The edge sheet portion 221 and the first and second grid sheet portions 223 and 225 refer to respective portions partitioned from the same sheet, which are integrally formed with each other.

The edge sheet portion 221 may be substantially connected to the edge frame portion 210. Accordingly, the edge sheet part 221 may have a substantially rectangular shape and a rectangular frame shape corresponding to the edge frame part 210.

In addition, the first grid sheet part 223 may extend in a first direction (horizontal direction). The first grid sheet part 223 may be formed in a straight line shape and both ends thereof may be connected to the edge sheet part 221. When the mask cell sheet portion 220 includes the plurality of first grid sheet portions 223, each of the first grid sheet portions 223 may be equally spaced apart.

In addition, in addition, the second grid sheet part 225 may be formed to extend in a second direction (vertical direction). The second grid sheet part 225 may be formed in a straight line shape and both ends thereof may be connected to the edge sheet part 221. The first grid sheet portion 223 and the second grid sheet portion 225 may vertically cross each other. When the mask cell sheet portion 220 includes a plurality of second grid sheet portions 225, each of the second grid sheet portions 225 preferably has an equal interval.

Meanwhile, the spacing between the first grid sheet portions 223 and the spacing between the second grid sheet portions 225 may be the same or different according to the size of the mask cell C. FIG.

The first grid sheet portion 223 and the second grid sheet portion 225 have a thin thickness in the form of a thin film, but the shape of the cross section perpendicular to the longitudinal direction may be a rectangle, a square shape such as a parallelogram, a triangular shape, or the like. The edges, edges, and corners may be partially rounded. The cross-sectional shape is adjustable in the process of laser scribing, etching and the like.

The thickness of the edge frame portion 210 may be thicker than the thickness of the mask cell sheet portion 220. The edge frame part 210 may be formed to a thickness of several mm to several cm because it is responsible for the overall rigidity of the frame 200.

In the case of the mask cell sheet unit 220, a process of manufacturing a substantially thick sheet is difficult, and if the thickness is too thick, a path through which the organic source 600 (see FIG. 16) passes through the mask 100 in the OLED pixel deposition process. This can cause problems. On the contrary, if the thickness is too thin, it may be difficult to secure rigidity enough to support the mask 100. Accordingly, the mask cell sheet part 220 is thinner than the thickness of the edge frame part 210, but preferably thicker than the mask 100. The mask cell sheet part 220 may have a thickness of about 0.1 mm to about 1 mm. In addition, the widths of the first and second grid sheet parts 223 and 225 may be formed to about 1 to 5 mm.

A plurality of mask cell areas CR: CR11 to CR56 may be provided except for an area occupied by the edge sheet part 221 and the first and second grid sheet parts 223 and 225 in the planar sheet. In another aspect, the mask cell region CR is an area occupied by the edge sheet portion 221 and the first and second grid sheet portions 223 and 225 in the hollow region R of the edge frame portion 210. Except for, it may mean an empty area.

As the cell C of the mask 100 corresponds to the mask cell region CR, the mask C may be used as a passage through which the pixels of the OLED are deposited through the mask pattern P. FIG. As described above, one mask cell C corresponds to one display such as a smartphone. Mask patterns P constituting one cell C may be formed in one mask 100. Alternatively, one mask 100 may include a plurality of cells C, and each cell C may correspond to each cell region CR of the frame 200. It is necessary to avoid the large area mask 100, and the small area mask 100 provided with one cell C is preferable. Alternatively, one mask 100 having a plurality of cells C may correspond to one cell region CR of the frame 200. In this case, for clear alignment, it may be considered to correspond to the mask 100 having a small number of cells C of about 2-3.

The frame 200 may include a plurality of mask cell regions CR, and each mask 100 may be bonded such that one mask cell C corresponds to the mask cell region CR. The mask cell C may correspond to the mask cell region CR of the frame 200, and part or all of the dummy may be attached to the frame 200 (mask cell sheet portion 220). Accordingly, 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 by bonding the mask cell sheet portion 220 to the edge frame portion 210, the edge frame portion 210 in the hollow region (R) portion of the edge frame portion 210 ), A frame in which a grid frame (corresponding to the grid sheet portions 223 and 225) which is integral with one another can be used immediately. The frame of this type also includes at least one mask cell region CR, and the mask integrated region may be manufactured by corresponding the mask 100 to the mask cell region CR.

Since the mask 100 of FIGS. 9 and 10 has a short length including one cell C, the degree of distortion of the pixel position accuracy (PPA) may be reduced. For example, assuming that a length of a mask including a plurality of cells C1 to C6, ... is 1 m, and a PPA error of 10 µm occurs in the entire 1 m, the mask 100 of the present invention has a relative length. According to the reduction (corresponding to the reduction of the number of cells C), the above error range may be 1 / n. For example, if the length of the mask 100 of the present invention is 100mm, since it has a length reduced to 1/10 in 1m of the conventional mask, a PPA error of 1㎛ occurs in the entire 100mm length, alignment error There is an effect that is significantly reduced.

On the other hand, if the mask 100 is provided with a plurality of cells (C), each cell (C) corresponding to each cell region (CR) of the frame 200 is within a range that the alignment error is minimized, The mask 100 may correspond to the plurality of mask cell regions CR of the frame 200. Alternatively, the mask 100 having the plurality of cells C may correspond to one mask cell region CR. Also in this case, in consideration of the process time and productivity according to the alignment, it is preferable that the mask 100 has as few cells as possible.

In the case of the present invention, since only one cell C of the mask 100 needs to be corresponded and the alignment state checked, the plurality of cells C: C1 to C6 must be simultaneously associated and the alignment state must be confirmed. Compared with the conventional method, manufacturing time can be reduced significantly.

That is, in the method of manufacturing a frame-integrated mask of the present invention, each cell C11 to C16 included in the six masks 100 corresponds to one cell region CR11 to CR16, respectively, and checks the alignment state. Through the process, the time can be much shorter than the conventional method of simultaneously matching six cells C1 to C6 and simultaneously confirming the alignment of the six cells C1 to C6.

In addition, in the method of manufacturing a frame-integrated mask of the present invention, the product yield in 30 steps of matching and aligning 30 masks 100 with 30 cell areas CR: CR11 to CR56, respectively, results in six cells (C1). 5 masks each comprising ˜C6) may appear much higher than the conventional product yield in 5 steps of matching and aligning the frame. Since the conventional method of aligning six cells C1 to C6 in a region corresponding to six cells C at a time is much more cumbersome and difficult, the product yield is low.

11 is a schematic diagram illustrating 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 magnet plate 300 in which a magnet 310 is accommodated and a coolant line 350 is disposed, and an organic material source 600 from a lower portion of the magnet plate 300. And a deposition source supply unit (500) for supplying ().

A target substrate 900 such as glass on which the organic source 600 is deposited may be interposed between the magnet plate 300 and the source deposition unit 500. In the target substrate 900, the frame-integrated masks 100 and 200 (or FMMs) for allowing the organic material 600 to be deposited pixel by pixel may be closely attached or very close to each other. The magnet 310 may generate 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 supply the organic source 600 while reciprocating the left and right paths, and the organic source 600 supplied from the deposition source supply unit 500 may have patterns P formed in the frame integrated masks 100 and 200. ) May be deposited on one side of the target substrate 900. The deposited organic source 600 passing through the pattern P of the frame-integrated masks 100 and 200 can act as the pixel 700 of the OLED.

In order to prevent non-uniform deposition of the pixel 700 by the shadow effect, the pattern of the frame-integrated masks 100 and 200 may be formed to be inclined S (or formed into a tapered shape S). . Since the organic sources 600 passing through the pattern in a diagonal direction along the inclined surface may also contribute to the formation of the pixel 700, the pixel 700 may be uniformly deposited as a whole.

Since the mask 100 is adhesively fixed to the frame 200 at a first temperature higher than the pixel deposition process temperature, even if the mask 100 is raised to the process temperature for pixel deposition, the position of the mask pattern P is hardly affected. The PPA between the 100 and the neighboring mask 100 may be maintained not to exceed 3 μm.

Although the present invention has been shown and described with reference to preferred embodiments as described above, it is not limited to the above embodiments and various modifications made by those skilled in the art without departing from the spirit of the present invention. Modifications and variations are possible. Such modifications and variations are intended to fall within the scope of the invention and the appended claims.

50: buffer substrate
55: temporary adhesive
100: mask
110: mask film, mask metal film
200: frame
210: border frame portion
220: mask cell sheet portion
221: border sheet portion
223: first grid sheet portion
225: second grid sheet portion
1000: OLED pixel deposition device
C: cell, mask cell
CM: chemical treatment
CR: mask cell area
DM: Dummy, Mask Dummy
ET: Is heat
P: mask pattern
US: Ultrasound
UV: UV is applied

Claims (28)

As a method of manufacturing a mask for forming an OLED pixel,
(a) providing a mask metal film;
(b) adhering a mask metal film on a buffer substrate having a temporary adhesive portion formed on one 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;
Including,
The mask metal film is produced by a rolling or electroforming process,
The temporary adhesive is liquid wax or thermal release tape that can be separated by applying heat or can be separated by UV irradiation.
The buffer substrate is a mask made of any one of a wafer, glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia. Method of preparation. delete The method of claim 1,
between steps (b) and (c),
And reducing the thickness of the mask metal film adhered to the buffer substrate. The method of claim 3,
The thickness reduction of the mask metal film is performed by any one of chemical mechanical polishing (CMP), chemical wet etching, and dry etching. The method of claim 1,
When the mask metal film is produced by electroplating, the step (a) may include
(a1) forming a mask metal film on at least one surface of the conductive single crystal substrate; And
(a2) separating the mask metal film from the conductive single crystal substrate
It includes, the manufacturing method of the mask. The method of claim 5,
A method of manufacturing a mask, which further performs a step of heat-treating the mask metal film between steps (a1) and (a2). delete delete The method of claim 1,
Liquid wax is fixed to the mask metal film and the buffer substrate at a temperature lower than 85 ℃, manufacturing method of the mask. The method of claim 9,
In step (b), 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 between the rollers to perform adhesion. The method of claim 1,
In step (b), before the mask metal film is bonded, a laser passing hole is formed in a portion of the buffer substrate corresponding to the welded portion of the mask. The method of claim 11,
A method of manufacturing a mask, which penetrates through the laser through hole to a portion of the temporary bonding portion on the buffer substrate. The method of claim 1,
(c) step,
(c1) forming a patterned insulating portion on the mask metal film;
(c2) etching a portion of the mask metal film exposed between the insulating parts to form a mask pattern; And
(c3) removing the insulation
It includes, the manufacturing method of the mask. The method of claim 1,
After the step (c), the mask metal film comprises a plurality of mask cells in which a plurality of mask patterns are formed. The method of claim 1,
After step (c), the mask metal film includes one mask cell in which a plurality of mask patterns are formed. The method of claim 1,
Step (d) is a step of separating the mask metal film and the buffer substrate by performing at least one of heat application, chemical treatment, ultrasonic application, and UV application to the temporary bonding portion, the manufacturing method of the mask. The method of claim 15,
In step (d), any one of a solvent debonding, heat debonding, peelable adhesive debonding, and room temperature debonding method may be used. Manufacturing method. The method of claim 1,
The mask is a method of manufacturing a mask, which is a material of any one of invar, super invar, nickel, nickel-cobalt. A buffer substrate for supporting a mask for forming an OLED pixel,
Buffer substrate;
A temporary adhesive portion formed on the buffer substrate; And
A mask on which a mask pattern is formed by adhering on a buffer substrate through a temporary adhesive portion
Including,
The mask includes a mask metal film manufactured by a rolling or electroforming process,
The temporary adhesive is liquid wax or thermal release tape that can be separated by applying heat or can be separated by UV irradiation.
The buffer substrate is a mask made of any one of a wafer, glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia. Support buffer substrate. The method of claim 19,
A mask supporting buffer substrate, wherein the mask metal film has a thickness of 5 µm to 20 µm. delete delete delete The method of claim 19,
A mask support buffer substrate, wherein a laser passage hole is formed in a portion of the buffer substrate corresponding to the welded portion of the mask and the temporary bonded portion. The method of claim 19,
The mask support buffer substrate comprising a plurality of mask cells in which a plurality of mask patterns are formed. The method of claim 19,
The mask support buffer substrate comprising a mask cell in which a plurality of mask patterns are formed. delete A method of manufacturing a buffer substrate for supporting an OLED pixel forming mask and corresponding to a frame,
(a) providing a mask metal film;
(b) adhering a mask metal film on a buffer substrate having a temporary adhesive portion formed on one surface thereof; And
(c) forming a mask pattern on the mask metal film to manufacture a mask
Including,
The mask metal film is produced by a rolling or electroforming process,
The temporary adhesive is liquid wax or thermal release tape that can be separated by applying heat or can be separated by UV irradiation.
The buffer substrate is a mask made of any one of a wafer, glass, silica, heat-resistant glass, quartz, alumina (Al ₂ O ₃ ), borosilicate glass, and zirconia. Method for producing a support buffer substrate.

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