This application claims priority to Japanese Patent Application No. 2003-403070 filed Dec. 2, 2003 which is hereby expressly incorporated by reference herein in its entirety.
1. Field of the Invention
The present invention relates to a mask, a method for manufacturing a mask, and a method for manufacturing an organic electroluminescent device (EL) and an organic EL device.
2. Related Art
As a method for manufacturing a low-molecular full-color organic EL panel, there is a method in which a deposition pattern is selectively formed through a mask so as to separately color each red, blue, and green luminescent layer on a glass substrate. For example, when a metal mask is used as the mask, deposition is conducted in a condition where the mask is adhered to one side of the glass substrate by a permanent magnet placed on the other side of the. glass substrate. However, when a large-size panel is manufactured with a metal mask, there is a problem in which a position of the mask deviates from that of the glass substrate, since there is a large difference between a thermal expansion coefficient of the mask and that of the glass substrate.
Therefore, there have been developments of a deposition mask that has less difference in the thermal expansion coefficient between the mask and the glass substrate and that uses a single crystalline Si wafer that can be more finely processed by micro electro mechanical systems (MEMS). Also, Japanese Unexamined Patent Publication No. 2003-100460, for example, discloses a technique in which the mask strength is increased by mounting a plurality of small Si mask chips on a large-size substrate material provided with apertures.
However, by the technique of the above-mentioned Japanese Unexamined Patent Publication No. 2003-100460, a slight bending occurs when fixing a Si mask chip to an aperture. Because of this bending, a gap is created between the mask and a glass substrate used as a material to be deposited on (a layer-formation object material), and the resulting deposition pattern may possibly be unclear.
In view of these issues, the present invention aims to provide a mask that is reliable, for example, for deposition and that can form a desired high-precision layer pattern on, for example, a glass substrate used as a layer-formation object material, and a method for manufacturing the mask. Further, the present invention aims to provide a method for manufacturing an organic EL device using the mask.
To solve the problems, the mask of the present invention includes a first substrate having a first aperture and a plurality of second substrates each having second apertures serving as mask apertures of the mask of the invention, wherein the second apertures are placed inboard of the first aperture and the second substrate is partially bonded to the first substrate.
Upon a series of inquiries made by the present inventors, it has been discovered that the cause of the bending generated when fixing the above-mentioned Si mask chip to a large-size substrate material was in the fixation method, and thereby the present invention has been developed. That is to say, when a second substrate having an aperture for a mask is bonded to a first substrate having a first aperture, the problem of the bending created on the substrates is solved by partially bonding the second substrate to the first substrate even if an expansion and shrinkage of the substrates occur, since effect of the expansion and shrinkage of the substrates will be lessened at the non-bonded parts, and a desired high-precision layer pattern can be formed by, for example, depositing the mask. As a result, a gap between a mask and a layer-formation object material does not easily appear, and thereby a desired high-precision layer pattern can be formed. Moreover, because the second substrate is reinforced by the first substrate according to the present invention, the mask has very high strength.
Additionally, the second substrate and the first substrate can be bonded with an adhesive agent, which can be formed partially on one second substrate. In this case, also, a desired high-precision layer pattern can be formed. Moreover, since the bonding procedure using an adhesive agent is very simple, it is possible to provide the mask at low cost. Further, the second substrate can have a structure bonded to the first substrate over a plurality of points, and that, when an adhesive agent is used as described, the adhesive agent can be arranged over a plurality of places for one second substrate.
Further, the second substrate is formed rectangularly, and only a corner of the second substrate is bonded to the first substrate. Also, only one side each that opposes the other side of a primary surface of the second substrate is bonded partially to the first substrate (two adjacent sides are bonded). Moreover, only an area of the second substrate close to a center of a side having the largest expansion of all sides of a primary surface of the second substrate can be bonded to the first substrate. In any of these structures, a desired high-precision layer pattern can be formed using the mask.
Also, more than two second substrates can be bonded to the first substrate sharing the same adhesive agent. This can simplify the adhesive agent supply procedure at the same time as it can form a desired high-precision layer pattern using the mask.
Further, an alignment mark used when bonding the second substrate to the first substrate can be placed on each substrate, with each substrate being bonded in close proximity to the alignment mark. In this case, the procedure for aligning the first substrate and the second substrate will be relatively easy compared to when forming the bonding portion apart from an alignment mark.
For the mask of the present invention, the second substrate can be formed with a silicon wafer. By forming the second substrate with a silicon wafer, the difference between a thermal expansion coefficient of the mask and that of the glass substrate or the like as a layer-formation object material will be small, thereby preventing the position of the mask from deviating from the position of the layer-formation object material.
To solve the aforementioned problem, the method for manufacturing the mask of the present invention includes the steps of: laminating a first substrate having a first aperture and a plurality of second substrates each having second apertures serving as mask apertures so that the second apertures are placed inboard of the first aperture, and, in the laminating step, partially bonding the second substrates to the first substrate. By this manufacturing method, the above-described mask of the present invention can be suitably manufactured. Also, in the laminating step, the second substrate is partially bonded to the first substrate using an adhesive agent, which can be formed on a part of the first substrate and/or a part of the second substrate.
Further, by using a rectangular primary surface of a substrate as the second substrate, only a corner of the second substrate can be partially bonded to the first substrate in the laminating step. Also, in the laminating step, only one side each that opposes the other of the second substrate may be partially bonded to the first substrate (two adjacent sides are bonded). Moreover, in the laminating step, only an area of the second substrate close to a center of a side having the largest expansion coefficient of all sides of a primary surface of the second substrate may be partially bonded to the first substrate.
Next, the method of manufacturing an organic EL device according to the present invention includes forming an organic EL element using the mask of the present invention. Of organic EL elements, a luminescent material (organic material) that forms a luminescent layer, for example, can be formed into a layer by deposition. By conducting deposition through the mask, a highly reliable organic EL device having a luminescent layer in a predetermined pattern may be obtained.
FIGS. 1A-B are a flat pattern view and a cross sectional pattern view showing one embodiment of the mask of the present invention.
FIGS. 2A-B are a flat pattern view and a cross sectional pattern view showing an enlarged principal part of the mask in
FIGS. 8A-B are a flat pattern view and a cross pattern sectional view for describing one method for manufacturing the organic EL in accordance with the present invention.
FIGS. 9A-C are cross sectional pattern views for describing one method for manufacturing the organic EL in accordance with the present invention.
Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.
The first substrate 10 may be composed of a transparent substrate such as a glass substrate. On the first substrate 10, at least one (in
On the first substrate 10, a first alignment mark 14 is formed. The first alignment mark 14 is used for aligning the first substrate 10 with the second substrate 20 when bonding them together. The first alignment mark 14 may be formed with a metal film or by etching. Also, on the first substrate 10, a mask-positioning mark 16 is formed. The mask-positioning mark 16 is used for positioning the mask of the present embodiment when conducting deposition using the mask. The mask-positioning mark 16 can also be formed with a metal material. Further, the mask-positioning mark 16 may be formed on the second substrate 20.
The second substrate 20 is formed rectangularly, similarly outlining the aperture 12, and a plurality of through-holes 22 (see
On the second substrate 20, a second alignment mark 24 is formed. The first and the second substrates 10 and 20 are aligned with each other using the first and the second alignment marks 14 and 24. The second alignment mark 24 may be formed by etching the second substrate 20 or may be formed with a metal film.
A plurality of second substrates 20 are mounted on the first substrate 10. As shown in
The adhesive agent 91 is confined to a corner of the second substrate 20, which is bonded to the first substrate 10 only at the corner. Therefore, a degree of freedom of the substrates increases in comparison with a structure in which the entire periphery of the second substrate 20 is adhered to the first substrate 10. Even if there is a case in which the second substrate 20 is expanded due to heat or the like in the adhering procedure, a problem of the bending of the second substrate 20 does not easily take place.
Next,
In the second substrate 20, a plurality of through-holes 22 are formed. For their formation, etching (e.g. anisotropic etching having crystal-surface orientation dependency) may be applied. A wall surface of the through-hole 22 may be perpendicular to the surface (primary surface) of the second substrate 20 or may be tapered. As shown in
Next, the adhesive agent 91 is applied to one corner of the periphery of each aperture 12 of the first substrate 10. For the adhesive agent 91, a highly adhesive, epoxy UV curing adhesive agent (light curing resin) with low outgas in a vacuum may be employed, or a heat curing resin may be employed. In addition, the adhesive agent 91 may be applied, for example, to one corner of the rectangular second substrate 20 or to both a corner of the first substrate 10 and a corner of the second substrate 20.
The thus prepared first substrate 10 and the second substrate 20 are then aligned with each other, bonded with the adhesive agent 91 which has been applied thereon. Here, a plurality of second substrates 20 are arranged on one surface of the first substrate 10 in such a way that the second substrates 20 do not overlap one another. Additionally, for their alignment, the first and the second alignment marks 14 and 24 are used. After aligning, the first and the second substrates 10 and 20 are adhered to each other by illuminating the adhesive agent 91.
By this method, the second substrate 20 is reinforced by the first substrate 10, enabling a mask to be manufactured with a high strength. Further, even when expansion or shrinkage occurs on the first and/or the second substrate 10 and/or 20, the effect of expansion or shrinkage on the substrates will be lessened at the non-bonded (non-adhered) part since the adhesive agent 91 is applied to only one corner for bonding, and, therefore, a problem such as the bending of the substrates will be solved. As a result, a gap between a layer-formation object material and the mask will not easily appear, and thereby the mask of the present embodiment having a desired high-precision layer pattern can be formed by, for example, deposition.
In addition, as shown in
Furthermore, as shown in
In the present embodiment, a luminescent material is formed into a layer on a substrate (layer-formation object material) 54 using the mask 50. The substrate 54 is used for forming a plurality of organic EL devices and is a transparent substrate such as a glass substrate. On the substrate 54, as shown in
As shown in
In the present embodiment, the second substrate 20 serving as a screen is partially bonded to the first substrate 10. Therefore, the second substrate 20 has a high degree of freedom and does not easily bend or deform and shows a high repeatability in selective deposition and high productivity. With the mask 50 of the present embodiment, a plurality of apertures 12 are formed on the first substrate 10, and the second substrates 20 are placed corresponding to each aperture 12. Each second substrate 20 corresponds to one organic EL device. In other words, by using the mask 50, a plurality of unified organic EL devices can be manufactured. By cutting the substrate 54, separate. organic EL devices can be obtained.
As an example of an electronic apparatus having the organic EL device, a mobile phone 500 is illustrated in
Additionally, it is to be understood that the present invention is not limited to any of the embodiments as herein described, that modifications can be properly effected within the entire scope and spirit of the invention, and that any method for manufacturing a substrate used for an electro-optical device, any substrate used for electro-optical device, any electro-optical device, and any electronic apparatus associated with such modifications shall be included in the scope of the present invention.
Number | Date | Country | Kind |
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2003-403070 | Dec 2003 | JP | national |