JP2003231964A - Evaporation mask, its manufacturing process, organic electroluminescent device and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporation mask which can make the width of reinforcement line narrow as much as possible, its manufacturing process and an organic electroluminescent device having a large open area ratio using this evaporation mask. <P>SOLUTION: The evaporation mask has an aperture pattern corresponding to an evaporation pattern employed upon evaporating an evaporation material onto a substrate. The evaporation mask consists of multiple layers, wherein a first layer positioned at the substrate side upon evaporation comprises a mask part and reinforcement lines. Apertures a corresponding to the evaporation pattern are formed on the first layer, and apertures b, which are larger than the apertures a on the first layer, are formed on a second layer or layers beneath this. The apertures a and the reinforcement lines on the first layer are exposed through the apertures b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition mask used for forming a thin film pattern, a method for manufacturing the same, and an organic electroluminescence device having a thin film layer formed using the vapor deposition mask.

[0002]

2. Description of the Related Art An organic electroluminescence device emits light by recombining holes injected from an anode and electrons injected from a cathode in an organic light emitting layer sandwiched between both electrodes. A typical structure thereof is one in which a first electrode formed on a substrate, a thin film layer including at least a light emitting layer made of an organic compound, and a second electrode are laminated, and light emitted by driving is emitted from a transparent side of the device. Is taken out from the.
Such an organic electroluminescent device is capable of thin-type, high-luminance light emission under low-voltage driving, and multicolor light emission by selecting an organic compound in the light-emitting layer, and is applied to light-emitting devices, displays, and the like.

In manufacturing an organic electroluminescent device, it is necessary to pattern a light emitting layer and the like, and various manufacturing methods have been studied. When fine patterning is required, a photolithography method is used as a typical method. Although the photolithography method can be applied to the formation of the first electrode of the organic electroluminescent device, it is often difficult to apply the formation of the light emitting layer and the second electrode due to the problems associated with the wet process. Therefore, dry processes such as vacuum deposition, sputtering, and chemical vapor deposition (CVD) are applied to the formation of the light emitting layer and the second electrode. As a means for patterning and forming a thin film by such a process, a method using a vapor deposition mask is often applied.

The patterning precision of the light emitting layer of an organic electroluminescent device used as a display is considerably high.
In the simple matrix method, the light emitting layer is formed on the first electrode patterned in a stripe shape. The line width of the first electrode is usually 100 μm or less and the pitch thereof is about 100 μm. In addition, it is essential that the second electrode is formed in a stripe shape with a pitch of several 100 μm, has a low electric resistance in the length direction of the elongated electrode, and the electrodes adjacent to each other in the width method are completely insulated. is there. Also in the active matrix system, the light emitting layer is patterned with the same or higher definition.

Therefore, the vapor deposition mask used for the patterning also necessarily has high definition. Since such a mask has a large influence of deformation due to bending,
In order to maintain the pattern processing accuracy by maintaining the size and shape of the opening, a reinforcing wire partially introduced is often used as needed (for example, see Patent Document 1).

An example of a conventional vapor deposition mask used for patterning a light emitting layer is shown in FIG. It has an opening 32 corresponding to each pixel and a reinforcing line 33 for preventing its deformation. The opening is a pattern corresponding to the pixel of the organic electroluminescent device, and the reinforcing line is located in the non-light emitting area which is a gap between the pixels. If the cross section of the vapor deposition mask is vertical as shown in FIG. 11, the vapor deposition mask itself becomes a shadow on the vapor deposition material and a uniform pattern cannot be obtained. Therefore, as shown in FIGS. 12 and 13, there is disclosed a technique of reducing the influence of vapor deposition shadows by forming a cross section into a tapered shape (for example, Patent Document 2).
reference). Further, as shown in FIGS. 14 and 15, a technique is disclosed in which the cross section of the vapor deposition mask is T-shaped to reduce the influence of the vapor deposition shadow (for example, Patent Document 3,
4).

Generally, the dimensional error of a vapor deposition mask is proportional to its size. When manufacturing an organic electroluminescent device using a relatively large-sized substrate, a large vapor deposition mask is used, and thus the vapor deposition mask is required to have higher accuracy. In the so-called multi-chamber manufacturing in which many organic electroluminescent devices are manufactured from one substrate, the integrated mask method in which a plurality of vapor deposition masks correspond to one substrate is used, and patterning accuracy is deteriorated due to an increase in dimensional error of the vapor deposition masks. There is known a method for preventing the above (see Patent Documents 5 and 6, for example).

[0008]

[Patent Document 1] JP-A-11-214154 (paragraph number 29, FIG. 17)

[0009]

[Patent Document 2] Japanese Patent Laid-Open No. 10-298738 (claim 1, FIG. 2)

[0010]

[Patent Document 3] Japanese Unexamined Patent Publication No. 2001-126865 (paragraph number 26, FIG. 2B)

[0011]

[Patent Document 4] Japanese Patent Laid-Open No. 2001-237072 (paragraph number 12, FIG. 2)

[0012]

[Patent Document 5] Japanese Unexamined Patent Publication No. 2000-113978 (claim 4, paragraph number 24, example 1)

[0013]

[Patent Document 6] Japanese Patent Application Laid-Open No. 2002-83679 (Claim 1, Example 1, FIG. 1)

[0014]

However, in the tapered shape disclosed in Patent Document 2, the reinforcing wire has a trapezoidal cross section as shown in FIG. The minimum processing dimension of the vapor deposition mask is W1
Therefore, the reinforcing line width W2 on the substrate side inevitably has a larger value. The T-shape shown in Patent Document 4 also causes the same problem as shown in FIG. When the reinforcing line width is wide, it is necessary to increase the gap between pixels, that is, to design the non-light emitting region to be large, so that the aperture ratio, which is the area occupation ratio of the pixel, decreases. Therefore, there is a problem that the emission brightness and durability of the display are reduced. Further, even when the multi-faceted manufacturing is performed by the integrated mask method, since the reinforcing line width of each vapor deposition mask becomes wide as described above, there is a similar problem.

An object of the present invention is to provide a vapor deposition mask which solves such a problem and which can make the reinforcing line width as thin as possible, and a method for producing the same, and by using the vapor deposition mask, an organic film having a high aperture ratio can be obtained. An object of the present invention is to provide an electroluminescent device.

A further object of the present invention is to provide a method for producing an organic electroluminescent device having a high aperture ratio by multi-faced production with high productivity.

[0017]

SUMMARY OF THE INVENTION The present invention is a vapor deposition mask having an array of openings corresponding to a vapor deposition pattern used when vapor depositing a vapor deposition material on a substrate, the vapor deposition mask comprising a plurality of layers. The first layer, which is located on the substrate side during vapor deposition, is composed of a mask portion and a reinforcing line, the opening a corresponding to the vapor deposition pattern is formed in the first layer, and the second layer or the second and subsequent layers is formed. The vapor deposition mask is characterized in that an opening b larger than the opening of the first layer is formed in the layer, and the opening b exposes the opening a of the first layer and the reinforcing wire.

In a preferred embodiment, the vapor deposition mask of the present invention is composed of a second layer, and the opening b exposes the opening a and the reinforcing wire of the first layer.

The method of manufacturing a vapor deposition mask of the present invention is
It is characterized by including at least the following steps A to C. A: A step of forming a first layer on an electroforming mother die by an electroforming method. B: A step of forming a second layer or a layer after the second layer on the first layer. C: A step of peeling the laminate from the electroformed mother die.

Further, the organic electroluminescent device of the present invention is characterized in that the thin film layer of the organic electroluminescent device is formed using the vapor deposition mask.

Further, the method for manufacturing an organic electroluminescence device of the present invention is characterized in that a plurality of vapor deposition masks are arranged on one substrate and a thin film of the organic electroluminescence device is patterned.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The vapor deposition mask of the present invention is used when a vapor deposition material is vapor-deposited on a substrate, and is particularly preferably used for manufacturing an organic electroluminescence device.

The organic electroluminescent device has a first electrode, a thin film layer including a light emitting layer made of at least an organic compound, and a second electrode on a substrate. A method of manufacturing an organic electroluminescent device having such a laminated structure is roughly as follows, but the present invention is not limited to this.

A photolithography method is applied to a transparent substrate on which a transparent electrode film such as indium tin oxide (ITO) is formed to pattern-form a plurality of stripe-shaped first electrodes arranged at regular intervals. .

Next, a thin film layer including at least a light emitting layer made of an organic compound is formed on the patterned first electrode.

In the present invention, the structure of the thin film layer of the organic electroluminescence device is not particularly limited, and for example, 1) hole transport layer /
It may be any of a light emitting layer, 2) a hole transporting layer / a light emitting layer / an electron transporting layer, 3) a light emitting layer / an electron transporting layer, and 4) a light emitting layer in which a combination substance of the above is mixed in one layer. .

Of these, it is the light emitting layer that must be patterned. In the case of a full-color display, three types of light emitting layers are sequentially formed by using light emitting materials corresponding to three emission colors having emission peak wavelengths in three regions of red (R), green (G), and blue (B). Form.

Subsequently, a second electrode is formed. In the simple matrix method, a plurality of stripe-shaped second electrodes, which are arranged on the thin film layer so as to intersect with the first electrodes and are arranged at regular intervals, are patterned. On the other hand, in the active matrix method, the second electrode is often formed in a solid manner over the entire display area. Since the second electrode is required to have a function as a cathode capable of efficiently injecting electrons, a metal material is often used in consideration of the stability of the electrode.

After patterning the second electrode, sealing is performed,
An organic electroluminescent device is obtained by connecting a drive circuit. Note that the first electrode may be an opaque electrode and the second electrode may be transparent so that light can be extracted from the upper surface of the pixel. Further, the first electrode may be the cathode and the second electrode may be the anode.

The vapor deposition mask of the present invention is particularly preferably used for patterning a light emitting layer in the production of the above organic electroluminescent device. Furthermore, the exemplified R, G, B3
It can be applied not only to an organic electroluminescent device having a color light emitting region, but also to a vapor deposition mask for patterning a light emitting layer of a segment type or area (zone) color display. The display formed here may be a simple matrix type or an active matrix type using a TFT (thin film transistor) or the like.

An example of the vapor deposition mask of the present invention is shown in FIGS. An opening a (32 in the figure) having a shape corresponding to a light emitting layer pattern which is a vapor deposition pattern and a reinforcing wire 33 are provided in the first layer 30 located on the substrate side during vapor deposition.

The reinforcing wire is introduced to prevent the deformation of the opening a and is not intended to mask the deposit. Therefore, the reinforcing line is arranged so as to be located in the non-light emitting region in the gap between the pixels so that the shadow of the reinforcing line does not occur on the pixel.

The second layer 31 is provided with an opening b (34 in the figure) larger than the opening a of the first layer. When a plurality of layers of three or more layers are provided, an opening b larger than the opening a of the first layer may be provided in the third and subsequent layers.

When the vapor deposition mask is composed of two layers, the reinforcing line is provided only on the first layer, and when it is composed of three or more layers, the layer immediately before the layer having the opening b larger than the opening a of the first layer is provided. You can set up to. When the vapor deposition mask is composed of two layers, the opening b of the second layer exposes the opening a of the first layer and the reinforcing wire.

By adopting the above multi-layer structure, the first layer can be formed relatively thin and the opening a can be formed with high precision.
Moreover, the reinforcing wire can be thin. Since the vapor deposition pattern is defined by the opening a of the first layer, the accuracy of the target vapor deposition pattern is improved. Further, since the reinforcing wire can be made thin, the non-light emitting region can be designed small, and an organic electroluminescent device having a large aperture ratio and excellent durability can be obtained.

One of the purposes of providing the second and subsequent layers is to improve the strength of the vapor deposition mask. As shown in FIG. 1, the vapor deposition mask is often fixed to the frame 35 for easy handling. At this time, tension is applied to the vapor deposition mask, but the first layer alone cannot withstand this tension,
There may be a problem that the dimensions of the vapor deposition mask are elongated or wrinkles occur. This problem can be solved by adding the second and subsequent layers.

Further, by making the opening b of the second layer or the layers after the second layer larger than the opening of the first layer, the influence of the above-mentioned vapor deposition shadow is reduced. That is, the evaporation shadow can be reduced by making the angle θ in FIG. 2 larger than the incident angle of the evaporation material. It is more preferable that the cross section of the first layer is tapered. The taper shape of the thin first layer is superior in dimensional accuracy to the taper shape of the entire vapor deposition mask. Of course, the second layer may be tapered.

The method of aligning the vapor deposition mask and the substrate of the present invention is not particularly limited, but preferably, the vapor deposition mask is provided with a position mark for aligning the relative position with the substrate. This position mark is often formed by an opening, but a high-precision pattern is required because it serves as a position reference. Therefore, for example, as shown in FIG. 1, it is preferable that the position mark 36 is formed only on the first layer and an opening is provided on the second layer so that the position mark is completely exposed.

In the vapor deposition mask of the present invention, the first layer, which is directly related to the precision of the vapor deposition pattern and the position mark, should be as thin as possible. This is because the thinner one can be processed with higher accuracy. On the other hand, if the first layer is too thin, the breakage of the reinforcing wire and the influence of the surface condition of the second layer may cause problems. Therefore, the thickness of the first layer is preferably in the range of 1 to 30 μm, more preferably in the range of 5 to 20 μm.

When the vapor deposition mask of the present invention comprises two layers,
The thickness of the second layer is not particularly limited, but considering that its role is to improve the strength of the vapor deposition mask and it is important to reduce the vapor deposition shadow, it is thicker than the first layer and not excessively thick. It is preferable. Specifically, the thickness of the second layer is 1
It is preferably in the range of 0 to 100 μm, and 15 to 15
More preferably, it is within the range of 50 μm. If necessary, the third and subsequent layers may be formed. In that case,
Depending on the film structure, it is preferable to appropriately select the film thickness of the first and subsequent layers from the viewpoint described above. The method for controlling the film thickness is not particularly limited, and a known method can be used.

In the vapor deposition mask of the present invention, regarding the protrusion width W3 of the first layer, for example, the alignment error when forming the first layer and the second layer, the vapor deposition shadow, the strength of the first layer, etc. It is preferable to select the optimum value in consideration. Specifically, it is preferable to select from the range of 5 to 50 μm.
More preferably, it is in the range of 0 to 30 μm.

The vapor deposition mask of the present invention is made of, for example, a metallic material such as stainless steel, a copper alloy, an iron-nickel alloy, an aluminum alloy, or various resin materials, but the material used is not particularly limited. Absent. A magnetic material may be used as the vapor deposition mask material when the strength of the mask is not sufficient because the pattern is fine and it is necessary to improve the adhesion to the substrate of the organic electroluminescence device by magnetic force. Preferable examples are pure iron, carbon steel, W steel and Cr.
Quench hardening magnet materials such as steel, Co steel, KS steel, MK steel,
Precipitation hardening magnet materials such as AlNiCo steel, NKS steel, and CuNiCo steel, sintered magnet materials such as OP ferrite and Ba ferrite, and Sm-Co system and Nd-Fe-B.
Metallic core materials such as alloys (Permalloy), Mn-Zn
Examples thereof include ferrite magnetic core materials such as Ni-Zn series and Cu-Zn series, and powder magnetic core materials obtained by compression molding fine powder such as carbonyl iron, Mo permalloy, and Sendust together with a binder. It is preferable to manufacture the vapor deposition mask from a thin plate-shaped molding of these magnetic materials, and it is also preferable to use rubber or resin mixed with powder of the magnetic material and molded into a film.

The first layer of the vapor deposition mask of the present invention may come into contact with the substrate. Electrostatic discharge occurs between the board and
The formed thin film layer may be damaged. To prevent this, the first layer is preferably made of a conductive material. Specifically, the electrical resistivity is preferably 1 Ωcm or less. Further, the vapor deposition mask may be grounded through the vapor deposition apparatus by making the adhesive that adheres to the frame conductive. Fixing to the frame is not limited to a method using an adhesive, and a welding method using a laser or an electron beam or a mechanical fixing method using a screw or the like may be used.

The method for producing the vapor deposition mask of the present invention is not particularly limited, and examples thereof include etching method, mechanical polishing, sandblast method, sintering method, laser processing method, use of photosensitive resin, and the like. It is preferable to use an electroforming method which is excellent in processing accuracy.

A preferred method of manufacturing a vapor deposition mask is shown in FIG.
9 will be used for explanation.

First, a resist pattern 38 is formed on the electroformed mold 37 by using a normal photolithography method or the like (FIG. 4). This resist pattern corresponds to the pattern of the opening a of the first layer and the position mark. Next, Ni, a Ni—Co alloy, or the like is deposited on the electroforming mother die by electroforming to form a pattern of the first layer 30 in the mask portion (FIG. 5). After the resist pattern is once removed, the resist pattern 39 is formed again (FIG. 6). The pattern of the second layer 31 of the mask portion is formed on the first layer by electroforming (FIG. 7). The resist pattern is removed and the laminated body is peeled from the electroformed mold (FIG. 8). The vapor deposition mask is obtained by adhering to the frame 35 while applying tension to this laminated body (FIG. 9) and cutting off unnecessary portions. The first layer and the second layer do not necessarily have to be formed of the same material. The composition of each layer can be optimized as needed.

In the present invention, the vapor deposition material is not particularly limited, and, for example, suitable examples of the vapor deposition material for forming the organic electroluminescent device include a hole injection layer, a hole transport layer, and a light emitting layer (host and guest). Examples include organic materials that form the electron transport layer and the electron injection layer. Preferably, the molecular weight is 20
Low molecular weight organic materials of 0-2000 are used. The form of the low molecular weight organic material is not particularly limited, but is usually in the form of powder. Further, the metal material forming the second electrode in the organic electroluminescence device can also be mentioned as the vapor deposition material.

The process of depositing the vapor deposition material on the substrate to form the thin film layer is not particularly limited. For example, the vapor deposition material that is solid at room temperature is filled in the vapor deposition source, and the vapor deposition source is heated to melt the vapor deposition material. Or sublimate. A method in which a thin film layer is formed by depositing vapor of the vapor deposition material on a substrate is preferably used.

In the present invention, the material used for the substrate is not particularly limited, but for example, glass, ceramics,
Semiconductors and resins are preferably used. The glass, ceramics and semiconductor preferably have a thickness of 1.1 mm or less and 0.1 mm or more, and the resin has a thickness of 0.5 mm or less and 0.1 mm or less.
It is preferably in the form of a film of 05 mm or more. This is because a thinner substrate is advantageous in terms of weight and the like, and a substrate having a certain thickness or more is advantageous in manufacturing.

The mask vapor deposition method is a batch process for each substrate. Since the current organic electroluminescent device has many small-sized applications, multi-faceted manufacturing is usually used to improve the productivity.

Generally, a small organic electroluminescent device is required to be patterned more accurately than a large organic electroluminescent device. Furthermore, in order to obtain multiple surfaces, it is necessary to prepare a vapor deposition mask having a large number of precise aperture arrangement portions corresponding to the size of one organic electroluminescent device. Therefore,
A vapor deposition mask for manufacturing a small organic electroluminescent device using a large substrate has both local dimensional accuracy corresponding to one organic electroluminescent device and total dimensional accuracy in which a large number of them are arranged. It is necessary to be satisfied.

In the present invention, a large-sized vapor deposition mask may be prepared, and one thin film layer may be arranged for one large substrate to pattern the thin film layer, but preferably a relatively small vapor deposition mask. An integrated mask method is used in which a mask is formed, a plurality of vapor deposition masks are arranged on one substrate, and a thin film layer is patterned.

The smaller the vapor deposition mask, the easier it is to maintain the dimensional accuracy with high precision. Therefore, when the substrate becomes large, an integrated mask formed by aligning a plurality of small vapor deposition masks on the base plate is used. It is preferable to realize highly accurate patterning, and the effect of the present invention is more remarkably exhibited.

When the integrated mask is used, the number of vapor deposition masks arranged on one substrate is not particularly limited, but it is preferably in the range of 2 to 16 and more preferably 2 to 9 Is the range.

The thin film layer to be patterned in the present invention is not particularly limited, but it is preferably an R, G, B light emitting layer.

[0056]

The present invention will be described below with reference to examples.
The invention is not limited by these examples.

Example 1 (Preparation of Vapor Deposition Mask) A resist pattern was formed on a stainless steel electroformed mold by photolithography. Next, by the electroforming method, 1 is applied to the region of the mask portion where there is no resist pattern on the electroforming master.
Ni-Co alloy is deposited as a layer, 10 to 12 μm
Formed to a thickness of. After removing the resist pattern, a resist pattern was formed again by the photolithography method. A Ni—Co alloy was similarly deposited as a second layer of the mask portion in a region where there was no resist pattern on the first layer by electroforming to form a film having a thickness of 20 to 28 μm. After removing the resist pattern, the laminate was peeled off from the electroforming mother die, and the second layer side was adhered to a stainless steel frame having a width of 4 mm while applying tension to prepare a vapor deposition mask.

An outline of the produced vapor deposition mask is shown in FIGS.
Will be explained. The outer shape of the vapor deposition mask is 120 x 84 m
m. The opening a (32 in the figure), the reinforcing line 33, and the position mark 36 are formed in the first layer. Opening 32
Is a rectangle having a width of 100 μm and a length of 280 μm, 272 pieces at a pitch of 300 μm in the width direction, and 3 in the length direction.
200 pieces are formed at a pitch of 00 μm. The reinforcing line width is 20 μm, and the opening width of the position mark is 20 μm. The opening b (34 in the figure) of the second layer completely exposes the opening 32 of the first layer, the reinforcing line 33, and the position mark 36. That is, the second layer is not formed on the reinforcing wire 33. In FIG. 2, the projection width W from the first layer to the second layer
3 was 10 to 15 μm, and the angle θ was 20 degrees.
As shown in FIG. 1, the second layer is not formed in the area around the position mark. The dimensions of the opening, reinforcement line, position mark and distance between position marks are ±
It was less than 5 μm, and it was confirmed that the dimensional accuracy was high.

Comparative Example 1 An evaporation mask was tried to be produced in the same manner as in Example 1 except that the second layer was not formed. However,
The dimension of the distance between the position marks differs from the design value by 10 μm or more. Furthermore, only a wavy form was obtained as a whole, and the flatness of the vapor deposition mask deteriorated.

Comparative Example 2 A vapor deposition mask was prepared in the same manner as in Example 1 except that the second layer having a width of 20 μm was formed on the reinforcing wire of the first layer.
A study was conducted to narrow the reinforcing line width of the layer. This 20 μm
The value is a standard of the critical dimension when the vapor deposition mask is manufactured by the electroforming method. In order to reduce the influence of evaporation shadows, the protrusion width from the second layer of the first layer in the reinforcement line portion is secured to be 10 μm, and further the alignment error of the first layer and the second layer is expected to be ± 5 μm when manufacturing the evaporation mask. For this reason, the reinforcing line width of the first layer had to be 50 μm. That is, this comparative example 1 in which a second layer was further formed on the reinforcing wire of the first layer.
In comparison with Example 1, only a vapor deposition mask having a wider reinforcing line width could be obtained.

Comparative Example 3 A vapor deposition mask having a one-layer structure having a tapered cross section as shown in FIGS. 12 and 13 was produced by inclining the cross section of the resist pattern when producing the vapor deposition mask. The thickness of the vapor deposition mask was 35 ± 5 μm, which was approximately equal to the total thickness of the vapor deposition mask of Example 1. The minimum processing dimension W1 of the vapor deposition mask is about 20 μm, and the reinforcing line width W2 on the substrate side
Was about 45 μm. That is, only the vapor deposition mask having a wider reinforcing line width than in Example 1 was obtained. Further, since the opening width of the position mark was largely varied in the range of 5 to 30 μm, the alignment accuracy was poor.

Example 2 (Production of Organic Electroluminescent Device) A photoresist was applied on an ITO glass substrate having a size of 120 × 100 mm, exposed and developed to form an ITO film in a stripe shape having a length of 90 mm and a width of 80 μm. Patterned. 816 stripe-shaped first electrodes are arranged at a pitch of 100 μm.

Next, a positive photoresist ("OFPR-800" manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied by a spin coating method to a thickness of 3 μm on the substrate on which the first electrode was formed. The coating film was pattern-exposed through a photomask, developed to pattern the photoresist, and cured at 200 ° C. after development. In this insulating layer, there are 816 openings having a width of 70 μm and a length of 250 μm at a pitch of 100 μm in the width direction and 300 μm in the length direction.
200 pieces are arranged at a pitch. The insulating layer covers the edge portion of the ITO and the ITO is exposed from the opening. The thin film layer including the light emitting layer was formed by a vacuum evaporation method using a resistance wire heating method. The degree of vacuum during vapor deposition is 2 ×
The pressure was 10 ⁻⁴ Pa, and the substrate was rotated with respect to the vapor deposition source during vapor deposition. First, copper phthalocyanine is 15 nm and bis (N
-Ethylcarbazole) was evaporated to a thickness of 60 nm on the entire surface of the pixel area to form a hole transport layer. The vapor deposition mask of Example 1 was placed in front of the substrate to bring them into close contact with each other, and a ferrite plate magnet (YBM-1B manufactured by Hitachi Metals, Ltd.) was placed behind the substrate. At this time, the striped first electrode is located at the center of the opening of the vapor deposition mask, the reinforcing wire is located on the insulating layer,
In addition, the reinforcing wire and the insulating layer were placed in contact with each other. In this state, 0.3% by weight of 1,3,5,7,8-pentamethyl-4,4-difluoro-4-bora-3a, 4a-diaza-
Aluminum quinolinol complex doped with s-indacene (PM546 manufactured by Exxington) (hereinafter referred to as Al
(described as q3) was vapor-deposited to a thickness of 20 nm to pattern the green light emitting layer. Then, the shadow mask was aligned with the first electrode pattern at a position shifted by one pitch, and 1% by weight of 4- (dicyanomethylene) -2-methyl-6- (jurolidylstyryl) pyran (DCJT and Alq3 doped with (sometimes abbreviated) was vapor-deposited with a thickness of 15 nm to pattern the red light emitting layer. Further, the shadow mask was aligned with the first electrode pattern at a position shifted by one pitch, and 4,4′-bis (2,2′-diphenylvinyl) diphenyl was evaporated to a thickness of 20 nm to pattern the blue light emitting layer. The reinforcement line width of the vapor deposition mask is 20 μm, which is sufficiently smaller than the width of the insulating layer in the length direction of 50 μm. Therefore, when patterning the light emitting layer,
It was easy to align the substrate and the vapor deposition mask so that the reinforcing wire fits within the range where the insulating layer exists.
As a result, it was possible to completely cover the exposed portion of ITO, which is the first electrode, with each of the green, red, and blue light emitting layers.
Next, 4 parts of bathocuproin (phenanthroline derivative)
An electron transport layer was formed by vapor deposition on the entire surface of the 5 nm substrate. Then, the thin film layer was exposed to lithium vapor for doping (0.5 nm in film thickness conversion).

For patterning the second electrode, a shadow mask having a structure in which a gap exists between one surface of the mask portion and the reinforcing line was used. The shadow mask outline is 120
× 84 mm, the thickness of the mask portion is 100 μm, and 200 stripe-shaped openings having a length of 100 mm and a width of 260 μm are arranged at a pitch of 300 μm. On the mask portion, a mesh-shaped reinforcing wire having a regular hexagonal structure having a width of 38 μm, a thickness of 35 μm, and an interval between opposing two sides of 200 μm is formed. The height of the gap is 100 μm, which is equal to the thickness of the mask portion. The shadow mask is fixed to a stainless steel frame having the same outer shape and a width of 4 mm. The second electrode was formed by a vacuum evaporation method using a resistance wire heating method. The vacuum degree during vapor deposition is 3 × 10 ^-4 P
a or less, and the substrate was rotated with respect to the two vapor deposition sources during vapor deposition. Similar to the patterning of the light emitting layer, a shadow mask for the second electrode is placed in front of the substrate to bring them into close contact with each other,
A plate magnet was arranged behind the substrate. At this time, the both are arranged so that the insulating layer matches the mask portion. In this state, aluminum was vapor-deposited to a thickness of 240 nm to pattern the second electrode. A known partition wall method was used for patterning the second electrode. The substrate on which the patterning of the second electrode had been completed was taken out of the vapor deposition machine and transferred to an argon atmosphere having a dew point of -80 ° C or lower. In this low humidity atmosphere, the substrate and the sealing plate were attached and sealed using a curable epoxy resin. In this way, pitch 100 μm, number 81
A green light emitting layer, a red light emitting layer, and a blue light emitting layer which were patterned were formed on a stripe-shaped first electrode composed of six ITO films, and pitch 30 was formed so as to be orthogonal to the first electrode.
A simple matrix type color organic electroluminescent device in which 200 0 μm stripe-shaped second electrodes were arranged was produced. The aperture ratio is 58%. It was confirmed that a clear image display was possible when the obtained device was line-sequentially driven.

Comparative Example 4 An organic electroluminescent device was prepared in the same manner as in Example 2 except that the light emitting layer was patterned using the vapor deposition mask of Comparative Example 2. Since the reinforcing line width of the vapor deposition mask was 50 μm, which was about the same as the width of the insulating layer in the longitudinal direction of 50 μm, there was a portion where the light emitting layer could not completely cover the exposed portion of the ITO that was the first electrode. Therefore, a portion that does not emit light with desired characteristics is formed in a portion of the pixel.

In order to avoid this, the width of the insulating layer is set to 80.
It was necessary to design widely to about μm. In this case, the aperture ratio decreased to 51%. In order to obtain the same display brightness as that of the organic electroluminescence device manufactured in Example 2, it was necessary to increase the current density of the pixel by about 1.2 times. Therefore, the luminance half-life was reduced to about 80% of that of the organic electroluminescent device manufactured in Example 2.

Example 3 (Production of integrated mask) This will be described with reference to FIGS. 1 to 3, 16 and 17.

A mask portion 122 having a two-layer structure was produced in the same manner as in Example 1. The thickness of the first layer was about 10 μm and the thickness of the second layer was about 25 μm. While applying tension to the mask portion, the second layer side is made of a Kovar alloy frame 124.
To produce a vapor deposition mask 120. The outer shape of the frame is 82 mm x 103 mm, and the lower part is about 7 inside.
An opening of 0 mm × about 97 mm and an upper part of 63 mm × 90 mm was provided. The thickness of the frame is 2.
Two 5 mm ears 128 were provided.

The opening a32, the reinforcing line 33, and the position mark 126 are formed in the first layer. The openings a32 are rectangular with a width of 100 μm and a length of 280 μm, and 256 openings at a pitch of 300 μm in the width direction and 300 μ in the length direction.
200 pieces are formed at an m pitch. Reinforcement line width is 20μ
m, and the opening width of the position mark is also 20 μm.

Similar to the first embodiment, the opening b of the second layer completely exposes the opening a of the first layer, the reinforcing line and the position mark. That is, the second layer is not formed on the reinforcing line and in the peripheral area of the position mark. Four vapor deposition masks 120 were produced. It was confirmed that the dimensions of the openings, the reinforcing lines, the position marks, and the distance between the position marks of each vapor deposition mask were less than ± 5 μm with respect to the design value, and the dimensional accuracy was high.

Next, 220 mm × 235 mm, thickness 12 m
m Kovar alloy plate, the top is about 70 mm ×
Aperture 1 of about 97 mm and the lower part is about 93 mm x about 114 mm
The base plate 102 was provided with a total of four 10 in a 2 × 2 arrangement. The four vapor deposition masks were arranged so that the opening of each vapor deposition mask was at the center of the opening of the base plate.

A pressing plate 14 is provided for one vapor deposition mask.
2. Each of the vapor deposition masks was fixed on the base plate by the two engaging means 140 composed of 2, the compression spring 144, and the fulcrum 148, and the integrated mask 101 in which the rough alignment was performed was produced.

At the center of the base plate, a width of 4 mm and a length of 21
A glass plate 104 having a thickness of 0 mm and a thickness of about 6 mm is attached. On the upper surface 108, the cross-shaped reference mark 106
A and the cross-shaped substrate reference mark 106B are arranged at pitches of 68 m so as to be symmetrical in the length direction of the glass plate.
m and 180 mm were provided for each two pieces. The reference mark was formed of a chromium film. The surface with the reference mark was set to be almost at the same height as the upper surface of the vapor deposition mask attached to the base plate. The gap between the vapor deposition mask and the glass plate was 2 mm, and the gap between the vapor deposition masks adjacent to each other with the engaging means interposed was 18 mm.

The position of the vapor deposition mask was adjusted with reference to the reference mark 106A to perform precise alignment. The displacement amount from the predetermined position of the vapor deposition mask was 3 μm or less for all four.

The distance between the openings and the position marks of the integrated mask as a whole was less than ± 8 μm with respect to the design value, and an integrated mask with high dimensional accuracy was obtained.

Example 4 (Manufacturing of multiple sides of organic electroluminescent device) An ITO transparent electrode film as a first electrode having a thickness of 300 nm was sputtered on a non-alkali glass surface having a thickness of 0.7 mm and an outer shape of 200 mm × 214 mm. The entire surface was formed. The first electrode film was patterned by the photolithography method. One unit consists of 768 stripe-shaped first electrodes having a length of 90 mm and a width of 82 μm arranged at a pitch of 100 μm in the width direction, and the position of the stripe-shaped first electrodes of each unit corresponds to that of each vapor deposition mask of the integrated mask. A total of 4 units were provided in an array of 2 rows × 2 rows so as to coincide with the openings. The four unit first electrodes correspond to four organic electroluminescent devices.

A positive photosensitive polyimide precursor (DL-1000 manufactured by Toray Industries, Inc.) was applied to the entire surface of the substrate by spin coating. The coated film after drying was exposed through a photomask and then developed to pattern the polyimide precursor film. Then, curing was performed at 230 ° C. for 10 minutes. Four unit spacers were formed so as to cover the entire effective light emitting areas (regions occupied by the R, G, and B light emitting layers later) of the four organic electroluminescent devices. In the case of one unit of spacer, 70 μm in the width direction of the stripe-shaped first electrode and 240 μm in the length direction are provided with openings of 768 (100 μm pitch) and 200 (300 μm pitch) openings, respectively. The first electrodes were arranged in a grid pattern so that the central portion of the first electrodes was exposed.

Copper phthalocyanine of 15 nm and bis (N-ethylcarbazole) of 60 nm were vapor-deposited on the entire effective light emitting areas of the four organic electroluminescent devices to form a hole transport layer. The degree of vacuum during vapor deposition was set to 2 × 10 −4 Pa or less, and the substrate was rotated with respect to the vapor deposition source during vapor deposition.

The substrate was placed on the integrated mask prepared in Example 3 to deposit the emissive layer. On the substrate, two ITO transparent electrode films having a diameter of 300 μm are provided as reference marks so as to be center-symmetrical with a pitch of 180 mm. The position of the reference mark was detected, and the glass substrate and the integrated mask were aligned so as to match the substrate reference mark 106B of the integrated mask.

As a green light emitting layer, 0.3 wt% of 1,
3,5,7,8, -Pentamethyl-4,4-difluoro-
4-bora-3a, 4a-diaza-s-indacene (PM
8-hydroxyquinoline-aluminum complex (abbreviated as Alq3) doped with 546) was deposited to a thickness of 20 nm according to the pattern of the integrated mask.

After the positions of the substrate and the integrated mask are shifted by 100 μm (1 pitch) in the width direction of the ITO transparent electrode and aligned, 1% by weight of 4% of a red light emitting layer is formed.
15 nm of Alq3 doped with (dicyanomethylene) -2-methyl-6 (julolidylstyryl) pyran (abbreviated as DCJT) was deposited. Then, the position of the substrate and the integrated mask is further 100 μm (1 pitch)
After shifting and aligning, 4,4′-bis (2,2′-diphenylvinyl) diphenyl (abbreviated as DPVBi) was vapor-deposited in a thickness of 20 nm as a blue light emitting layer. These RGB light emitting layers respectively correspond to the stripe-shaped ITO transparent electrodes and completely covered the exposed portions of the ITO transparent electrodes.

As the electron transport layer, 60 n of 4,4′-bis (phenanthroline-2-yl) tetraphenylmethane was used.
m was vapor-deposited on the entire effective light emitting area of four organic electroluminescent devices. Next, lithium was vapor-deposited in a film thickness conversion amount of 0.5 nm to dope the electron transport layer.

Length 10 in the width direction of the stripe-shaped first electrode
0 mm, width 250 μ in the lengthwise direction of the striped first electrode
m stripe-shaped second electrodes made of aluminum of 200 stripes arranged at a pitch of 300 μm as one unit, and 4 units are arranged so as to cover the openings of the spacers formed on the substrate previously manufactured. As possible, aluminum was vapor-deposited to form a 240 nm thick second electrode. The same integrated mask as in Example 3 was used for vapor deposition of the metal electrodes. The degree of vacuum during vapor deposition was set to 3 × 10 ⁻⁴ Pa or less.

This substrate was transferred from the vapor deposition apparatus to an argon atmosphere with a dew point of -90 ° C. In this low-humidity atmosphere, the substrate and a 0.7 mm-thick glass plate for sealing were attached to each other using an adhesive made of an epoxy resin for sealing.

The substrate on which the four organic electroluminescent devices were formed as described above was cut and divided into four organic electroluminescent devices. In each organic electroluminescence device, an organic layer including patterned light emitting layers of RGB is formed on 768 stripe-shaped first electrodes made of ITO, and is orthogonal to the first electrodes on the organic layer. Thus, 200 stripe-shaped second electrodes made of aluminum were formed. Of the intersections of the first and second electrodes, only the openings of the spacer emitted light. Since each RGB light emitting unit forms one pixel, 256 × at a pitch of 300 μm
A simple matrix type color organic electroluminescent device having 200 pixels was manufactured.

Each of the organic electroluminescent devices produced could display a clear image, and all four could be used as a display. Since the light emitting layer was vapor-deposited by dividing the vapor deposition mask, all four light emitting devices having the same dimensional accuracy and performance could be manufactured. That is, it was confirmed that four displays can be efficiently produced from one relatively large-sized substrate. The positional deviation of the R, G, and B light emitting layers of all the four organic electroluminescent devices was less than ± 10 μm.

[0087]

According to the vapor deposition mask of the present invention, it is possible to achieve a highly accurate opening size and a narrow reinforcing wire. Further, it is possible to improve the mask strength and reduce vapor deposition shadows. By using the vapor deposition mask of the present invention, the aperture ratio is increased, and an organic electroluminescence device excellent in brightness and durability can be manufactured. INDUSTRIAL APPLICABILITY The present invention is particularly effective in the case where a large number of organic electroluminescent devices are produced in multiple planes from one large substrate using the integrated mask.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a vapor deposition mask of the present invention.

FIG. 2 is a sectional view taken along the line AA ′ of FIG.

FIG. 3 is a sectional view taken along the line BB ′ of FIG.

FIG. 4 is a sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (first-layer resist pattern forming step).

FIG. 5 is a cross-sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (first layer mask portion forming step).

FIG. 6 is a sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (second-layer resist pattern forming step).

FIG. 7 is a cross-sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (second mask layer forming step).

FIG. 8 is a cross-sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (laminate peeling step).

FIG. 9 is a sectional view showing an example of a method for manufacturing a vapor deposition mask of the present invention (frame bonding step).

FIG. 10 is a plan view showing an example of a conventional vapor deposition mask.

11 is a sectional view (rectangular section) taken along the line AA ′ of FIG.

12 is a sectional view (tapered section) taken along the line AA ′ of FIG.

13 is a sectional view (tapered section) taken along the line BB 'of FIG.

14 is a cross-sectional view (T-shaped cross section) taken along the line AA ′ in FIG.

15 is a cross-sectional view (T-shaped cross section) taken along the line BB ′ of FIG.

FIG. 16 is a perspective view showing an integrated mask produced in Example 3;

FIG. 17 is a perspective view showing a method of assembling the integrated mask manufactured in Example 3;

[Explanation of symbols]

30 Mask part (first layer) 31 Mask part (second layer) 32 opening a (first layer) 33 Reinforcement line 34 Opening b (second layer) 35 frames 36 position mark 37 Electroforming mother die 38 Resist pattern (first layer) 39 Resist pattern (2nd layer) 101 integrated mask 102 base plate 104 glass plate 106A fiducial mark (for vapor deposition mask) 106B Substrate reference mark 108 upper surface 110 openings 120 evaporation mask 122 Mask part 124 frames 126 position mark 128 ears 140 engagement means 142 Press plate 144 compression spring 148 fulcrum

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3K007 AB02 AB11 AB18 DB03 FA01                 4K029 AA09 AA11 AA24 BA62 BB03                       BD00 CA01 DB06 HA03 HA04

Claims (5)

[Claims] 1. A vapor deposition mask having an array of openings corresponding to a vapor deposition pattern used when vapor depositing a vapor deposition material on a substrate, wherein the vapor deposition mask is composed of a plurality of layers and is on the substrate side during vapor deposition. The first layer located at is composed of a mask portion and a reinforcing line, the opening a corresponding to the vapor deposition pattern is formed in the first layer, and the opening of the first layer is formed in the second layer or the second and subsequent layers. An opening b larger than the part a is formed,
The vapor deposition mask, wherein the opening b exposes the opening a and the reinforcing wire of the first layer. 2. The vapor deposition mask according to claim 1, wherein the vapor deposition mask is composed of two layers, and the opening b exposes the opening a and the reinforcing wire of the first layer. 3. A method of manufacturing a vapor deposition mask according to claim 1, comprising at least the steps A to C described below. A: A step of forming a first layer on an electroforming mother die by an electroforming method. B: A step of forming a second layer or a layer after the second layer on the first layer. C: A step of peeling the laminate from the electroformed mother die. 4. An organic electroluminescent device, characterized in that a thin film layer of the organic electroluminescent device is formed by using the vapor deposition mask according to claim 1. 5. A method of manufacturing an organic electroluminescent device, comprising: disposing a plurality of vapor deposition masks according to claim 1 or 2 on one substrate to pattern a thin film layer of the organic electroluminescent device.