JP4126648B2 - Method for manufacturing metal mask member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a metal mask member capable of forming a highly accurate pattern as a metal mask for vapor deposition of an organic EL display or the like.
[0002]
[Prior art]
In recent years, full-color display, downsizing, and high-definition display devices represented by portable information devices have made rapid progress. In the manufacturing process of low-molecular-type organic EL displays that are in practical use, fine patterns such as light-emitting layers are formed by vapor deposition masks that have multiple through-holes. Metal masks are required to have a small and highly accurate aperture pattern.
A metal mask is a plate-like metal with a plurality of through-holes. The metal mask is opened by depositing organic substances, electrode materials, etc. on the substrate by vapor deposition or the like through a metal mask placed in front of the substrate. Pattern formation corresponding to the hole shape is performed.
[0003]
Such a metal mask having a plurality of through holes is generally manufactured by the following manufacturing method.
First, when a metal plate serving as a metal mask is prepared and a photoresist film having a desired pattern is formed on the surface of the metal plate and then etched, only a portion not covered with the resist is etched to form a through hole.
At this time, the direction of erosion of the metal mask material by the etching solution is not a single method, and proceeds not only in the thickness direction but also in the plane direction of the plate. Therefore, the through hole formed by etching has a problem that the opening area is larger than that of the original resist pattern.
[0004]
Since the degree of erosion in the plane direction is a major factor in processing time, it is considered the most effective means to reduce the thickness of the metal plate used as the metal mask in order to accurately form the aperture shape. It is done.
However, if the thickness of the metal plate serving as the metal mask is set to 20 μm or less, the following problem is newly generated.
Specifically, due to the deposition of the vapor deposition material, the weight of the deposited vapor deposition material becomes too heavy with respect to the metal plate serving as the metal mask, causing distortion. In addition, since the heat capacity is extremely small, distortion due to thermal expansion causes problems such as deterioration in mask position accuracy and insufficient pattern separation due to deposition wraparound.
In addition, when using a metal mask, tension is applied in advance to prevent distortion. However, a thin metal mask with a thickness of 20 μm or less has a large elongation with respect to the tension, and there is slight uneven tension. It becomes a cause of distortion and tension adjustment becomes difficult.
As means for solving the above problems, for example, Japanese Patent Application Laid-Open No. 10-50478 discloses a method of forming a hole with a thin plate material and reinforcing it.
[0005]
[Problems to be solved by the invention]
The method described in JP-A-10-50478 described above is to partially provide a reinforcing metal wire to prevent the thin metal mask from being bent. In such a portion, the deposition amount of the vapor deposition material is smaller than that in the portion without the reinforcing metal wire, and the film thickness is not uniform.
The objective of this invention is providing the manufacturing method of the member for metal masks which can form a highly accurate pattern film as a metal mask for vapor depositions, such as an organic EL display.
[0006]
[Means for Solving the Problems]
The inventor has intensively studied a method that does not use a wire as a reinforcing material, and a combination of a thin plate material for forming a through hole and a plate material for reinforcement is optimal, and further, a thin plate material for forming a through hole, As a result of studying the method of etching separately for the reinforcing plate material, the use of a laminated structure of a plurality of plate materials with different etching characteristics as the metal mask plate material improves the accuracy of the aperture shape, and the metal The inventors have found that the strength of the mask can be greatly improved and have reached the present invention.
[0007]
That is, the present invention comprises an opening forming layer for determining an opening size and a bonding layer for bonding the support layer, and the bonding layer is a dry film-forming layer, and the bonding layer is a hole-forming layer and a support layer. A layer is a manufacturing method of a member for a metal mask having different etching characteristics, and a dry film forming layer serving as a bonding layer is formed on a bonding surface of a plate material serving as a hole forming layer and a plate material serving as a support layer for determining a hole size. After the formation, a dry-bonded layer formed on the bonding surface with a pressure roll is pressure bonded to each other, and a laminate including a bonding layer for bonding a hole forming layer and a support layer for determining a hole size, It is a manufacturing method of the member for metal masks which performs heat diffusion heat processing to this laminated board .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As mentioned above, an important feature of the present invention lies in adopting a laminated structure of a plurality of metals as member for the metal mask.
The present invention is described in detail below.
First, the structure of a metal mask using the metal mask member of the present invention will be described with an example.
FIG. 1 is a schematic view showing an example of a cross-sectional structure of a metal mask using the metal mask member of the present invention. The metal mask shown in FIG. 1 joins a thin hole forming layer (1) made of a plate material, a support layer (3) made of a relatively thick plate material, and the hole forming layer (1) and the support layer (3). It is formed of three metal layers composed of the bonding layer (2).
By forming through holes (4) penetrating these layers in the hole forming layer (1), the support layer (3) and the bonding layer (2) by etching, a metal mask can be obtained.
[0009]
One of the important features in the cross-sectional structure of the metal mask using the metal mask member of the present invention is that all the layers constituting the metal mask can be easily etched. a) and the opening part (4-b) on the support layer side are etched with different etching patterns, and both hole shapes are different.
That is, the opening forming layer side opening portion (4-a) forms a small-diameter through hole in the through hole portion (4), and the opening forming layer side is formed on the thin opening forming layer (1) made of a thick plate material. By providing the opening portion (4-a), it is possible to form an opening size with high dimensional accuracy.
The thickness of the hole forming layer (1) made of a plate material is preferably as thin as possible in order to minimize the erosion in the plane direction when the hole is formed by etching, and is set to at least 10 μm or less. The dimensional accuracy of the through hole (4) can be suppressed to ± several μm.
[0010]
The thickness of the support layer (3) made of a plate material is preferably thick in terms of strength. However, if the thickness is too large, the through-hole portion (4) is shaded during vapor deposition, resulting in non-uniform deposition thickness.
Therefore, it is appropriate to set it to about 100 to 30 μm, which is about the same as or less than the minimum length of the through hole (4).
The bonding layer (2) serves as a binder for bonding the hole forming layer (1) and the support layer (3), and at the same time, the bonding layer is composed of the hole forming layer (1) and the support layer (3). When the metal having different etching characteristics is used, when the through hole portion (4) is formed by etching, the opening portion (4-a) on the opening forming layer (1) side and the support layer side opening portion (4-b) are formed. ) And a barrier for etching separately.
In the present invention, except the bonding layer due to the need for matching the thermal expansion characteristics, you thin bonding layer and those having different etching characteristics.
[0011]
In addition, although the thing of the above-mentioned three-layer structure was shown as an example of the metal mask using the member for metal masks of this invention, there also exists a two-layer structure, for example. In this case, the combination is an aperture forming layer and a support layer.
When manufacturing a metal mask member having such a two-layer structure, it is possible to overlap ordinary metal plates and join them together to reduce the thickness by rolling, or to laminate a metal on a support layer by a film forming method. It is good, but the method of stacking and joining ordinary metal plates together and reducing the thickness by rolling makes the thickness of the hole forming layer non-uniform or stacks the metal on the support layer by a film forming method Then, the metal to form into a film is limited, it cannot manufacture continuously as a strip | belt material, or manufacturing cost becomes high.
Therefore, in order to manufacture a metal mask member with a two-layer structure, two metal bands are unwound, dry etching is performed on the surfaces to be joined, an activated surface is formed, and pressure bonding is performed with a roll or the like at a low pressure reduction rate. This method is the most preferable method because it can not only continuously produce the band material, but also has little change in the thickness of the hole forming layer and the support layer.
However, the two-layer structure tends to warp during pattern deposition due to the difference in thermal expansion coefficient. Accordingly, the metal mask member of the present invention has a three-layer structure.
The metal mask member having a three-layer structure will be described below.
[0012]
As a method of manufacturing a laminated plate to be a member for a metal mask having a three-layer structure, a method of stacking and joining the metal plates described above and reducing the thickness by rolling, a method of sequentially forming a metal on the surface of the metal foil, A method of unwinding two metal laminated strips using a laminated material as a raw material, performing dry etching on the bonded surfaces to form an activated surface, and press-bonding with a roll or the like with a low pressure reduction rate, one or more pairs in a low pressure atmosphere There is a method in which a third metal is attached and formed on the surface of the metal foil and then joined by a pressure roll.
Among these, the method in which a third metal is dry-deposited on the surface of a pair of metal foils in a low-pressure atmosphere shown in 2001-162382 proposed by the applicant of the present invention, and then joined by a pressure roll is the most productive. Since the surface roughness of the hole forming layer is higher than that of plating, it is suitable as a method for producing the metal mask laminate.
In addition, since the dry film-forming layer is formed by adhesion, a bonding layer having a uniform thickness can be obtained, which is particularly preferable.
[0013]
In the present invention, of the support layer and the bonding layer formed of a hole forming layer and plate material made of a plate material, and more at least one, if the remaining layers in which etching characteristics different, selectively etching treatment It can be done.
Of the above-described layers, the metal material constituting the hole forming layer and the support layer can be any metal material having a low coefficient of thermal expansion in order to prevent a deposition pattern shift due to thermal expansion. Among these, considering availability and etching characteristics, it is particularly desirable to use, for example, an Fe—Ni alloy such as an Invar alloy or a 42% Ni alloy.
In addition, a super invar alloy to which Cr or Co is added, or an Fe-Ni-Cr alloy can be applied.
[0014]
At this time , if the hole forming layer (1) made of a plate material and the support layer (3) made of a plate material are made of the same material and the bonding layer is made of a different metal, the hole forming layer and the support layer are etched simultaneously. In addition, since it is necessary to match the thermal expansion characteristics except for the bonding layer, it is better to make the thin bonding layer have different etching characteristics. Desirably, the metal materials used for the hole forming layer and the support layer are the same. As the metal or alloy, the bonding layer may be a different metal.
[0015]
The material which comprises the joining layer of this invention is suitably selected from various metals as needed. For example, if the hole-forming layer made of a plate material and the support layer made of a plate material are made of an Fe—Ni based alloy as described above, it is preferable to have a high adhesive force and different etching characteristics from the Fe—Ni based alloy. It is preferable to use a metal such as Sn, Ag, or an alloy containing these as a main component.
As the thickness of the bonding layer, a thickness necessary for an etching barrier may be secured, and a thickness of about 1 μm is sufficient.
In the bonding of the hole forming layer and the support layer by the bonding layer, a heat diffusion heat treatment is combined in order to further increase the bonding force. At this time, a diffusion layer is newly formed. In the present invention, this diffusion layer is also defined as a bonding layer.
[0016]
【Example】
Hereinafter, the present invention will be described in detail based on examples and drawings.
FIG. 1 is a schematic view showing an example of a metal mask using the metal mask member of the present invention. The metal mask shown in FIG. 1 joins a thin hole forming layer (1) made of a plate material, a relatively thick support layer (3) made of a plate material, and the hole forming layer (1) and the support layer (3). It is formed of three metal layers composed of the bonding layer (2). Moreover, this cross-sectional microscope image is shown in FIG. The three-layer metal plate in FIG. 2 is a cross-sectional micrograph of a metal mask member and a schematic diagram thereof, the upper side being an aperture forming layer (1) made of a 10-μm thick Fe-42% Ni alloy, and the lower side being a 90 μm-thick Fe layer. A support layer (3) made of -42% Ni alloy, and a very thin layer at the center is a bonding layer (2) made of 1 μm Ti.
[0017]
As a method for producing a laminate for metal mask member comprising this metal mask, a Fe-42% Ni alloy serving as the hole forming layer in a low pressure atmosphere (10 [mu] m), a supporting layer Fe-42% Ni A method was adopted in which pure Ti was formed into a dry film (evaporated) on the bonding surface of the alloy (90 μm) and then bonded with a pressure roll.
Before joining, each Fe-42% Ni alloy is washed with hydrochloric acid to improve the joining strength. In this example, cleaning with hydrochloric acid was performed, but in addition to acid cleaning, a method such as dry etching that can be processed in a low-pressure atmosphere is also effective.
[0018]
The laminated plate made of the three-layer metal plate joined by the above method is slightly weak in bonding strength as it is, and it was 0.1 kN / m or less in the peeling test, so by performing heat diffusion heat treatment in an inert gas atmosphere, It was member for a metal mask by a bonding strength and strong.
In the peeling test after the heat diffusion heat treatment, the 10 μm-side Fe-42% Ni alloy as the hole forming layer was broken and could not be peeled off. Note that the heat diffusion heat treatment temperature for diffusion bonding of Ti in the bonding layer with each Fe-42% Ni alloy should be 400 ° C. or higher.
However, when heat-diffusion heat treatment is performed at about 650 ° C., the Fe-42% Ni alloy suddenly softens. Therefore, in order to improve the bonding strength without reducing the strength of the support layer material, the temperature is 400 ° C. to 500 ° C. Heat diffusion heat treatment is preferable.
[0019]
Opening portions were formed by selective etching using the above metal mask member, and the metal mask shown in FIG. 1 was created. A different etching pattern was used for each of the hole forming layer and the support layer. The etching pattern was a delta arrangement, and the width dimension of the aperture forming layer side aperture was 100 μm.
As the etching solution, ferric chloride was used for the hole forming layer and the support layer, and dilute hydrofluoric acid 3% was used for peeling the Ti layer.
The dimensions of the apertures were all in the range of 100 μm ± 5 μm, and a metal mask with high dimensional accuracy could be manufactured for high-definition display applications.
[0020]
【The invention's effect】
According to the present invention, the accuracy of vapor deposition pattern using a metal mask can be drastically improved, which is an indispensable technique for the practical use of a high-definition organic EL display.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of a metal mask using a metal mask member of the present invention.
FIG. 2 is a cross-sectional micrograph of a metal mask member of the present invention and a schematic diagram thereof.

Claims (1)

A bonding layer for bonding the hole forming layer for determining the hole size and the support layer; and the bonding layer is a dry film-forming layer, and the bonding layer is an etching characteristic of the hole forming layer and the support layer. Is a method of manufacturing a member for a metal mask having a different shape, and after forming a dry film forming layer to be a bonding layer on a bonding surface of a plate material to be a hole forming layer and a plate material to be a support layer for determining an opening dimension, press bonding A dry-bonded layer formed on the bonding surface with a roll is pressure-bonded to each other to form a laminated plate having a bonding layer for bonding a hole-forming layer for defining a hole size and a support layer, and the laminated plate is heated. A method for producing a metal mask member, comprising performing diffusion heat treatment.

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