JP2005005071A - Metal mask and method for mounting same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To give a desired tension to a metal mask easily so as to keep the metal mask in a state without distortion and slack when the metal mask is fixed to a frame like a picture frame. <P>SOLUTION: A rough surface is formed on a clamped area 1b in the periphery of a metal mask 1. When a clamp clamps and pulls the clamped area, the clamp does not cause the slip to the metal mask. The desired tension is given to the metal mask, and the metal mask can be kept in the state without distortion and slack. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal mask that is used by being fixed to a frame-like frame, such as a printing metal mask and a metal mask for vapor deposition, and a method for attaching the metal mask to the frame, and in particular, a vapor deposition step in manufacturing an organic EL element. The present invention relates to a metal mask suitable for use in the present invention and a method for attaching the metal mask to a frame.
[0002]
[Prior art]
[Patent Document 1] Utility Model Registration No. 3082805 Conventionally, a metal mask has been used for printing and vapor deposition on a substrate, and in many cases, the metal mask is used by being fixed to a frame-like frame. Yes. As a method for fixing the metal mask to the frame, there are a method using an adhesive, a method using welding, and the like (see Patent Document 1).
[0003]
[Problems to be solved by the invention]
By the way, in recent years, there is a demand for miniaturizing a pattern formed on a metal mask and reducing the thickness of the metal mask itself. For example, as a metal mask used for vacuum deposition for forming an organic layer or cathode electrode of an organic EL element, a mask having a pattern portion in which a large number of slits are arranged in parallel at regular intervals is used. There is a demand for reducing the width and slit interval and reducing the plate thickness. However, when fixing a thin metal mask having such a fine pattern to a frame-shaped frame, simply placing the metal mask on the frame and fixing it with an adhesive or by welding will cause distortion and sagging in the metal mask. It was found that a desired pattern could not be obtained. Therefore, as a result of investigations to prevent distortion and sagging that occur in the metal mask, the present inventors applied the tension in both the vertical and horizontal directions to the metal mask before attaching the metal mask to the frame, and stretched the metal mask flatly. By making it possible to adjust the applied tension locally within each side of the metal mask, it is possible to prevent distortion and sagging of the metal mask and secure a desired fine pattern with high accuracy. It has been found that by welding and fixing to the frame, a certain amount of tension remains in the metal mask, the metal mask is held in a flat state without distortion and sagging, and a predetermined fine pattern can be secured with high accuracy.
[0004]
However, it has been found that there is a new problem when applying tension to the metal mask. That is, in order to apply tension to the metal mask, each side of the metal mask is held with an appropriate clamp, and the clamp may be pulled by an air cylinder or the like, but the metal mask is pulled without any distortion or sagging. In some cases, considerable tension may be required. In this case, slippage may occur at the contact point between the metal mask and the clamp, which may cause a problem that the desired tension may not be maintained. It was. In order to pull each side of the metal mask without slipping, it is considered that a pin hole is formed in each side of the metal mask, a pin is inserted into the pin hole, and the pin is pulled by an air cylinder or the like. However, in the method of applying tension using the pin hole and pin fitting, tension is applied mainly to the narrow region where the pin hole and the pin are fitted, and the tension difference between the region with and without the pin hole is large, This tension difference may cause wrinkle-like deflection, and it is extremely difficult to secure a desired fine pattern. In some cases, too much tension is applied to a narrow region where the pin hole and the pin are fitted, and the pattern portion of the metal mask may be damaged.
[0005]
The present invention has been made in view of such a situation, and a metal mask capable of applying a desired tension to a metal mask by clamping a peripheral portion of the metal mask without causing a slip, and attaching the metal mask to a frame. It is an object to provide a method.
[0006]
[Means for Solving the Problems]
In the metal mask of the present invention, a clamp region is formed outside the region to be fixed to the frame-like frame, and slipping does not occur when the clamp region is grasped and pulled. A rough surface is formed on at least one of the front and back surfaces of the clamp region to increase the frictional resistance against the clamp.
[0007]
Here, the rough surface is preferably formed by half etching. Since etching is generally used for patterning a metal mask, the metal mask manufacturing process can be simplified by forming a rough surface by half etching in the clamp region simultaneously with the etching of the pattern.
[0008]
Further, it is preferable that an easy-cut line is formed in the metal mask at a position surrounding an effective area fixed to the frame and used. In this way, if an easy cutting line is provided at a position surrounding the effective area, after the metal mask is fixed to the frame, an unnecessary part including the clamp area on the outside can be easily used by using the easy cutting line. Can be cut and removed.
[0009]
The use of the metal mask of the present invention can be used for arbitrary printing, vapor deposition, and the like, and particularly suitable applications include vapor deposition of an organic layer of an organic EL element or a cathode electrode. Since this application requires a very fine pattern, the effect of applying the present invention is great. Further, at that time, it is preferable to provide a plurality of pattern portions on the metal mask, so that multi-surface deposition can be performed and productivity can be increased.
[0010]
In the metal mask mounting method of the present invention, the rough surface of the clamp region formed on the periphery of the above-described metal mask is held by the clamp, and tension is applied to the metal mask by the clamp so that there is no distortion or sagging. It is configured to be held in a state and fixed to the frame in that state, so that even if it is a thin metal mask with a fine pattern, the metal mask is flat without distortion or sagging And a predetermined fine pattern can be secured with high accuracy.
[0011]
In this method, it is preferable that unnecessary portions including the clamp region are removed after the metal mask is fixed to the frame.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described by taking a multi-sided metal mask used for vapor deposition in an organic EL element manufacturing process as an example. 1 is a schematic perspective view of a metal mask and a frame to which the metal mask according to the embodiment of the present invention is attached, FIG. 2 is a schematic perspective view showing the metal mask fixed to the frame, and FIG. 3 is an enlarged view of a part of the metal mask. It is a schematic plan view shown. 1 to 3, reference numeral 1 denotes a metal mask, and reference numeral 2 denotes a frame-like frame for supporting the metal mask 1. The metal mask 1 is formed of a thin metal plate such as an invar material or stainless steel, and includes a plurality of pattern portions 3 formed by arranging a large number of fine slits in parallel. Further, as shown in FIG. 1, the metal mask 1 before being attached to the frame 2 is spotted by placing it on the frame 2 while holding the side edge portions 1b of the four sides with appropriate clamps and applying tension. It is made larger in both the vertical and horizontal directions than the frame 2 so that it can be welded. Hereinafter, the side edge portion 1b gripped by the clamp is referred to as a clamp region. Further, the metal mask 1 has an easy-to-cut line 4 formed at a position surrounding the effective area 1 a that remains to be fixed to the frame 2. The easy cutting lines 4 can be easily cut by bending the metal mask 1 along the easy cutting lines 4 and are formed by half cuts, perforations, or the like. When a half cut is used as the easy cutting line 4, it is preferably formed by performing half etching simultaneously with the etching of the pattern portion 3. The easy cutting line 4 has a strength that can withstand the tensile force applied to the metal mask 1. Further, at least one of the front and back surfaces of the clamp region 1b of the metal mask 1 is roughened so that it is difficult to slip when gripped by the clamp. The shape of the rough surface is arbitrary, for example, those having a large number of independent protrusions or dents, those having a large number of parallel grooves or ridges, those having a large number of grooves or protrusions arranged, etc. Can be illustrated. The method for forming the rough surface is arbitrary, but it is preferable to form it by half etching because it can be formed simultaneously with the etching of the pattern portion 3. The surface roughness of the rough surface may be determined so as not to cause slipping as much as possible with respect to the clamp. For example, when the rough surface is formed by half etching, the half etching depth is 60 times the thickness of the metal mask. % Is preferable.
[0013]
The frame 2 has a frame shape including an opening 5 having a size including a region where a large number of pattern portions 3 of the metal mask 1 are formed. Further, the frame 2 does not bend or sag due to the tension of the metal mask 1 even after the metal mask 1 in a state where tension is applied is fixed. The metal mask 1 is provided with a large rigidity so that the metal mask 1 can always be kept flat even during handling such as during vapor deposition operation, and the frame 2 is sufficient to provide the rigidity. Thickness and width are given. As the material of the frame 2, a metal material such as stainless steel or invar material is usually used.
[0014]
The thickness of the metal mask 1, the dimension of the pattern portion 3, the dimension of the slit formed thereon, etc. are not particularly limited, but as a typical example, the thickness of the metal mask 1 is 30 to 200 μm, As for the dimensions, the length is 50 to 70 mm, the width is 30 to 50 mm, the width of the slit is 50 to 100 μm, the width of the fine metal wire constituting the slit is 100 to 150 μm, and the like. Further, the thickness of the frame 2 can be about 2 mm to 30 mm, and the width (the distance between the inner peripheral surface of the opening 5 and the outer peripheral surface of the frame) can be about 5 mm to 50 mm.
[0015]
Next, a method for attaching the metal mask 1 to the frame 2 will be described. FIG. 4 schematically shows a metal mask attaching apparatus used for attaching the metal mask to the frame. In FIG. 4, first, a frame 2 (not shown) is positioned and fixed at a predetermined position on a support base of a metal mask mounting device, and then a metal mask 1 is placed on the frame 2 and the metal mask 1 Each of the clamp areas 1b on the four sides is gripped by a plurality of clamps 11, and driving means 12 such as an air cylinder connected to each clamp 11 is operated so that each clamp 11 is vertically and horizontally indicated by arrows. Pull and apply a tensile force to the metal mask 1. Here, the plurality of clamps 11 provided on each of the four sides of the metal mask 1 are arranged in accordance with the rows of the pattern portions 3 and the regions without the pattern portions, and accordingly, the pattern portions 3 of the metal mask 1. It is possible to pull the region where the pattern is formed and the region where there is no pattern portion with the separate clamps 11, and thereby pull the regions with different rigidity of the metal mask 1 with the separate clamps 11 to adjust the tension. The metal mask 1 having regions of different rigidity can be adjusted to a flat state without distortion or sagging and to a state in which the slits of the pattern portion 3 are aligned in parallel. At this time, the clamp 11 grips the rough surface formed in the clamp region 1b of the metal mask 1, so that the slip does not occur and the tensile force by the driving means 12 is correctly transmitted to the metal mask 1. A desired tension can be applied to the metal mask 1. Next, the metal mask 1 is positioned so as to be in a predetermined position in the vertical and horizontal directions with respect to the frame 2 in a state where tension is applied by the clamp 11, and spot welding by laser irradiation is performed by a spot welding machine (not shown). (In the figure, reference numeral 20 indicates a spot welding mark). Thereby, the metal mask 1 is fixed to the frame 2 by welding. Thereafter, the clamp 11 is removed, and unnecessary portions of the metal mask 1 are removed using the easy cutting lines 4. As described above, as shown in FIG. 2, a mask assembly 9 for vapor deposition in which the metal mask 1 is fixed to the frame 2 is formed.
[0016]
In the obtained mask assembly 9, the metal mask 1 is kept in a state in which there is no distortion or sagging, and the slits of the pattern portion 3 are accurately aligned in parallel. Thereafter, a predetermined vapor deposition operation is performed using the mask assembly 9. That is, a deposition target substrate is attached to the mask assembly 9 and set in a deposition machine, and the organic layer or cathode electrode of the organic EL element is deposited. Thereby, vapor deposition of a fine pattern can be performed with high accuracy, and a high-quality organic layer or cathode electrode can be formed.
[0017]
In the above-described embodiment, when the metal mask 1 is fixed to the frame 2, a plurality of four sides of the metal mask 1 corresponding to the region corresponding to the pattern portion 3 and the region having no pattern portion are provided. However, the means for pulling the metal mask 1 is not limited to this configuration, and the metal mask 1 is pulled in a flat state free from distortion and sagging, and the slits of the pattern portion are aligned in parallel. If possible, it can be changed as appropriate. For example, the number of clamps provided on each side of the metal mask 1 and the width of the clamps may be changed, or each corner of the metal mask 1 may be changed in a diagonal direction. Further, in the above-described embodiment, both vertical and horizontal tensions are applied to the metal mask 1, but depending on the metal mask, the tension is applied only in one direction in the vertical direction or the horizontal direction, so that there is no distortion or sagging. In such a case, it is not always necessary to provide clamp regions having a rough surface on the four sides of the metal mask.
[0018]
【The invention's effect】
As described above, the present invention has a configuration in which a rough surface is formed in a clamp region for holding by a clamp of a metal mask, so that when the metal mask is attached to a frame, the clamp region is The metal mask can be gripped and pulled without causing any slippage. Therefore, a desired tension can be applied to the metal mask, and the metal mask can be fixed to the frame in a flat state without deflection or sagging. For this reason, in the mask assembly made by fixing this metal mask to the frame, the metal mask is in a flat state without distortion and sagging, and the pattern of the pattern portion is accurately maintained in a predetermined pattern, so that the high precision Can be used for printing and vapor deposition.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a metal mask and a frame to which the metal mask is attached according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of a metal mask assembly having a structure in which a metal mask is fixed to the frame. ] Schematic plan view showing a part of the metal mask in an enlarged manner [FIG. 4] Schematic plan view showing a state in which the metal mask is mounted on the frame in the metal mask mounting apparatus [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal mask 1a Effective area | region 1b Clamp area | region 2 Frame 3 Pattern part 4 Easy cutting line 5 Opening part 9 Mask assembly 11 Clamp 12 Driving means (air cylinder)
20 Spot welding marks

Claims (6)

A metal mask used by being fixed to a frame-like frame, comprising a clamp region located outside a region to be fixed to the frame, and having a rough surface on at least one surface of the clamp region A metal mask characterized by being formed. The metal mask according to claim 1, wherein the rough surface is formed by half etching. The metal mask according to claim 1 or 2, further comprising an easy-cut line formed at a position surrounding an effective area fixed to the frame and used. The metal mask according to any one of claims 1 to 3, wherein the metal mask is a multi-faced metal mask provided with a plurality of pattern portions for vapor deposition of an organic layer or a cathode electrode of an organic EL element. . When attaching the metal mask according to any one of claims 1 to 4 to a frame-like frame, a clamp region of the metal mask is held by a clamp, and tension in both vertical and horizontal directions is applied to the metal mask by the clamp. A method for attaching a metal mask, wherein the metal mask is held in a state free from distortion and sagging and fixed to the frame in that state. 6. The method of attaching a metal mask according to claim 5, wherein after the metal mask is fixed to the frame, unnecessary portions including the clamp region are removed.

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