Patent Application
20210074919
This application is based upon and claims the benefit of priority from the prior Japanese Application No. 2019-165584, filed on Sep. 11, 2019, the entire contents of which are incorporated herein by reference.
One embodiment of the present invention relates to a vapor deposition mask and a method of manufacturing the vapor deposition mask. In particular, one embodiment relates to a vapor deposition mask with a thin film mask body and a process for manufacturing the vapor deposition mask.
In the display device, a light emitting element is provided in each pixel, and an image is displayed by controlling the light emission individually. For example, in organic EL display device using an organic EL element as the light emitting element, the organic EL element is provided in each pixel, and the organic EL element has a structure in which a layer containing an organic EL material (hereinafter referred to as “organic EL layer”) is sandwiched between a pair of electrodes consisting of a anode electrode and a cathode electrode. Organic EL layer is composed of a functional layer such as light emitting layer, an electron injecting layer, and a hole injecting layer, and can emit light with colors of various wavelengths by selecting these organic materials.
A vacuum deposition method is used for forming thin film of organic EL element using a low-molecular compound as a material. In the vacuum deposition method, the vapor deposition materials are sublimated by heating them with heater in high vacuum, and the deposition materials are deposited (vapor deposition) on the surfaces of substrate to form a thin film. At this time, by using a mask (vapor deposition mask) having a large number of fine opening patterns, a high-definition thin film pattern is formed through the opening of the mask.
The deposition mask is classified into a fine metal mask (FMM) which is patterned by etching and an electrofine forming mask (EFM) which uses electroforming technology, depending on the manufacturing method. For example, Japanese Unexamined Patent Application Publication No. 2017-210633 discloses a method in which a mask portion having a high-definition opening pattern is formed using an electroforming technique, and the mask portion is fixed to the frame body portion using an electroforming technique.
A vapor deposition mask in an embodiment according to the present invention includes a mask body having a first surface and a second surface opposite to the first surface, and a holding frame connected to the first surface. The mask body is arranged with a mask pattern region having at least one opening, and a peripheral region surrounding the mask pattern region and having at least one hole or concave part on the second surface side.
A method for manufacturing vapor deposition masks in an embodiment according to the present invention includes forming a first resist pattern in a region corresponding to a mask pattern region of a substrate and a second resist pattern in a region corresponding to a peripheral region surrounding the mask pattern region of the substrate, forming a mask body formed of a metal layer on the substrate, the mask body has at least one opening formed by the first resist pattern, and has at least one hole or concave part formed by the second resist pattern, forming an insulating layer exposing an outer peripheral of the mask body and covering the at least one opening, arranging a holding frame on the outer peripheral of the mask body, forming a connecting member between the mask body and the holding frame, removing the insulating layer, and peeling the substrate from the mask body.
Embodiments of the present invention will be described below with reference to the drawings and the like. However, one embodiment of the present invention can be implemented in various modes without departing from the gist thereof, and should not be construed as being limited to the description of the following exemplary embodiments.
In order to make the description clearer, the drawings may be schematically shown with respect to width, thickness, shape, and the like of the respective portion in comparison with the actual embodiments. However, the examples shown in the drawings are merely illustrative and do not limit the interpretation of one embodiment of the present invention. In this specification and each of the drawings, the same reference numerals are assigned to the same components as those described above with reference to the above mentioned drawings, and detailed description thereof may be omitted as appropriate.
In the present specification and claims, when expressing an aspect in which another structure is disposed on a structure, it is defined to include both a case in which another structure is disposed directly above the structure so as to be in contact with the structure, and a case in which another structure is disposed above the structure via yet another structure, unless otherwise specified.
The vapor deposition mask disclosed in the Japanese Unexamined Patent Application Publication 2017-210633 suppress the generation of strain of frame body due to thermal expansion by reducing the difference in the amount of expansion due to heat at the respective portions of the frame body. However, if the alignment accuracy of the vapor deposition mask with respect to substrate is poor, the yield of the products will be reduced. Further, if a long time is required for alignment of the vapor deposition mask, the productivity of the product will be reduced.
One embodiment of the present invention is to provide a vapor deposition mask with improved deposition position accuracy and productivity.
With reference to
As shown in
The deposition chamber 100 has a configuration capable of accommodating an object on which a vapor deposition film is formed. Hereinafter, an embodiment in which the plate-like substrate 104 is used as the object will be described. As shown in
The deposition source 112 is filled with a material to be vapor-deposited (hereinafter referred to as “vapor deposition material”). Deposition source 112 has a heating unit 122 for heating the vapor deposition material (see
As shown in
Although the example shown in
The container 120 is a member for holding vapor deposition materials. As the storage container 120, for example, a member such as a crucible can be used. The storage container 120 is detachably held in the heating unit 122. The container 120 may include, for example, a metal such as tungsten, tantalum, molybdenum, titanium, or nickel, or an alloy composed of these metals. The container 120 may include an inorganic insulator such as aluminum oxide, boron nitride, or zirconium oxide and the like.
Heating unit 122 in the interior of the vapor deposition holder 124 is detachably held. The heating unit 122 is configured to heat the storage container 120 by a resistance heating method. Specifically, the heating unit 122 has a heater 126. By energizing the heater 126, the heating unit 122 is heated, and the vapor deposition material in the storage container 120 is heated and vaporized. The vaporized vapor deposition material is released from the opening 130 of the storage container 120 to the outside of the storage container 120. The mesh-like metallic plate 128 disposed so as to cover the opening 130 suppresses the ejection of the bumped vapor deposition materials out of the storage container 120. The heating unit 122 and the vapor deposition holder 124 may include the same material as the container 120.
The pair of guide plates 132 is provided on the top of the deposition source 112. At least a part of the guiding plate 132 is inclined with respect to the side surface or vertical direction of the storage container 120. By the slope of the guide plate 132, the angle at which the vapor of the vapor deposition material spreads (hereinafter, referred to as an injection angle) is controlled, so that the vapor can have directivity in the flying direction. The injection angle is determined by the angle θe formed by the two guide plates 132. The angle θe is appropriately adjusted depending on the size of substrate 104 and the distance between the deposition source 112 and the substrate 104. The angle θe is, for example, 40° or more and 80° or less, preferably 50° or more and 70° or less. In the present embodiment, the angle θe is 60°. The surfaces formed by the inclined surfaces of the guide plate 132 are the critical surfaces 160a and 160b. The vapor of the vapor deposition material flies substantially in the space sandwiched between the critical interfaces 160a and 160b. Although not shown, when the deposition source 112 is a point source, the guide plate 132 may be provided in a conical shape.
The vapor deposition material may be selected from a variety of materials and may be either the organic compound or the inorganic compound. As the organic compound, for example, a light-emitting material or a carrier-transporting material can be used. As the inorganic compound, a metal, an alloy, a metal oxide, or the like can be used. A plurality of materials may be filled in one storage container 120, and a plurality of materials may be mixed when vaporized. Although not shown, using a plurality of deposition sources may be configured so that different vapor deposition materials can be deposited at the same time.
The configuration of a vapor deposition mask according to an embodiment of the present invention will be described with reference to
A plurality of mask pattern regions 315 and peripheral region 317 around each mask pattern region 315 are arranged on the mask body 310. When depositing the organic EL material on the substrate 104, each mask pattern region 315 of the mask body 310 is disposed so as to correspond to the display region of the display device. Peripheral region 317 of the masking body 310 is arranged to correspond to the peripheral region of the display device. The masking body 310 has a first surface 310a located on the substrate 104 side during the deposition and a second surface 310b opposed to the first surface 310a. The second surface 310b of the mask body 310 is fixed to the holding frame 330 via connection member 350.
In each mask pattern region 315, a plurality of openings 311 penetrating the mask body 310 are provided in accordance with the pixel pitch of the display device. The region other than the opening 311 of the masked body 310 is called a non-opening region 312. The non-opening region 312 surrounds each opening 311. Non-opening region 312 corresponds to the portion of each mask pattern region 315 that shields the vapor deposition material.
During deposition, alignment of the vapor deposition mask 300 and substrate 104 is performed so that the opening 311 corresponds to the deposition region (region to be formed thin film) on the substrate 104 and the non-opening region 312 and the non-deposition region on the substrate 104 overlaps. The vapor of the vapor deposition material reaches the substrate 104 through the opening 311, thereby depositing the vapor deposition material on the deposition region to form a thin film.
In the present embodiment, the diameter of the opening end of opening 311 on the first surface 310a side is smaller than the diameter of the opening end on the second surface 310b side. In the opening 311, the diameter of the opening end on the first surface 310a side is the smallest, and the diameter of the opening end on the second surface 310b side is the largest. In other words, the opening 311 has a tapered configuration in which the diameter linearly changes in the deposition direction (Z direction from the second surface 310b to the first surface 310a). Since the opening 311 has a reverse-tapered configuration at the first surface 310a (reverse Z-direction from the first surface 310a side to the second surface 310b side), the vapor deposition materials can be suppressed from circulating under the mask. However, the configuration of the opening 311 is not limited thereto, and the diameter of the opening end on the first surface 310a side and the diameter of the opening end on the second surface 310b side may be substantially the same. Since the opening 311 has such construction, thin film having a fine pattern can be deposited.
In the present embodiment, peripheral region 317 is provided with a hole part 313 which is a through hole. During deposition, the alignment spacer for alignment of substrate 104 to be described later is fitted to the hole part 313, and the alignment of the vapor deposition mask 300 and the substrate 104 is performed. The hole part 313 is blocked by fitting the alignment spacer. Therefore, the hole part 313 corresponds to the portion shielding the vapor deposition material in the peripheral region 317. The region other than hole part 313 of peripheral region 317 corresponds to the non-opening region 312.
In the present embodiment, the diameter of the opening end of hole part 313 on the first surface 310a side is larger than the diameter of the opening end on the second surface 310b side. In the hole part 313, the diameter of the opening end on the first surface 310a side is the largest, and the diameter of the opening end on the second surface 310b side is the smallest. In other words, hole part 313 has a tapered configuration in which the diameter linearly changes in the direction in which the alignment spacer is fitted, i.e., in the reverse Z direction from the first surface 310a side to the second surface 310b side. Since the hole part 313 has a tapered configuration at the first surface 310a (reverse Z-direction from the first surface 310a side to the second surface 310b side), the hole part 313 and the alignment spacer can be easily fitted to each other, and the position of the masking body 310 and substrate 104 can be easily aligned with each other. Also, the alignment spacers have same tapered configuration so that the distances between the masking body 310 and substrate 104 can be adjusted. Since the contact area between hole part 313 and the alignment spacer is large, the dust generation from scratches on the alignment spacer can be suppressed by dispersing the load applied to the alignment spacer, thereby improving productivity. However, the configuration of the hole part 313 is not limited thereto, and the diameter of the opening end on the first surface 310a side and the diameter of the opening end on the second surface 310b side may be substantially the same. Since hole part 313 has such configuration, peripheral region 317 can be narrowed.
In the present embodiment, the hole part 313 is circular in the planar view. That is, the hole part 313 is a truncated cone-shaped through hole. Such configuration of the hole part 313 facilitates the fitting of the hole part 313 and the alignment spacer, and the position of the mask body 310 and the substrate 104 are easily aligned. In addition, since the hole part 313 does not have any corner, dust generation from scratches of the alignment spacer can be suppressed by dispersing stresses applied to the alignment spacer, and productivity can be improved. However, one embodiment of the present invention is not limited thereto, and the hole part 313 may have a polygonal shape in the planar view. The hole part 313 may be a truncated pyramid shaped through hole. By hole part 313 has a corner portion, it is possible to align the positional deviation of the masking body 310 and substrate 104 in the rotational direction of the X-Z plane around the Y direction axis.
The position of the opening 311 of the mask body 310 and the deposition region of the substrate 104 is deviated due to the stress and strain of the mask body 310 itself. However, since stress and strain generally tend to affect uniformly in the entire mask body 310, the misalignment can be minimized by performing alignment with reference to the central portion of the mask body. Since the hole part 313 according to the present embodiment has the above-described configuration, it is suitable for the pre-alignment in the vicinity of the center of the masking body 310, which is a reference point of the alignment. Therefore, hole part 313 in the present embodiment is arranged near the center of the masked body 310 at the planar view. However, one embodiment of the present invention is not limited thereto, and the hole part 313 may be provided at the position other than the center of the masking body 310. In this embodiment, one hole part 313 is provided in the peripheral region 317 of the masking body 310. However, one embodiment of the present invention is not limited thereto, and a plurality of hole part 313 may be provided in the peripheral region 317 or may be provided in the non-opening region 312 of the mask pattern region 315. The deposition position accuracy can be improved by providing a plurality of hole parts 313.
The holding frame 330 and the connection member 350 are disposed on the outer periphery of the masking body 310. The connection member 350 is overlapped with the mask body 310 in a planar view, and surrounds a plurality of mask pattern regions 315, i.e., a plurality of openings 311 of mask body 310. The holding frame 330 is not overlapped with the mask body 310 in a planar view, and is provided on the extension of the second surface 310b of the mask body 310. That is, in the horizontal direction, the inner surface 330a of the holding frame 330 is provided outside the outer edge 310c of the masking body 310. The second surface 310b of the masking body 310 is fixed to the inner surface 330a of the holding frame 330 via a connection member 350. The connection member 350 is arranged in contact with the inner surface 330a of the holding frame 330 and the second surface 310b of the masking body 310. Note that the horizontal direction is a direction parallel to main surface of the masking body 310. The inner surface 330a of the holding frame 330 indicates an inner edge on the center side of the holding frame 330.
In the above configuration, the mask body 310 is a plating layer, the thickness of the mask body 310 in the Z-direction is 3 μm or more and 10 μm or less. The connection member 350 is a plating layer, and the thickness (Z direction) of the connection member 350 on the second surface 310b of the masking body 310 and the thickness (X direction) of the connection member 350 on the inner surface 330a of the holding frame 330 are preferably 50 μm or more and 2000 μm or less.
As described above, the vapor deposition mask 300 according to the present embodiment includes the hole part 313 having the structure described above, it is possible to improve the deposition position accuracy and productivity when fixing the vapor deposition mask 300 to the substrate 104 by a magnet or the like.
A method of manufacturing the vapor deposition mask 300 according to an embodiment of the present invention will be described with reference to
The connection member 350 can be selectively formed on the mask body 310 exposed from the second insulating layer 470 and on the holding frame 330 by an electroplating method which energizes the mask body 310 and the retaining frame 330. The material of connection member 350 is not particularly limited, and for example, a magnetic material such as nickel (Ni) or nickel alloys can be used. The thickness (in the Z direction) of the connection member 350 on the second surface 310b of the masking body 310 and the thickness (in the X direction) of the connection member 350 on the inner surface 330a of the holding frame 330 are preferably 50 μm or more and 2000 μm or less.
As described above, according to the method of manufacturing the vapor deposition mask 300 according to the present embodiment, The hole part 313 is formed together with the opening 311, so that when the vapor deposition mask 300 is fixed to the substrate 104 by a magnet or the like, the deposition position accuracy and productivity can be improved.
A vapor deposition method using a vapor deposition mask according to an embodiment of the present invention will be described with reference to
In the present embodiment, the diameter d1 of the upper end of the alignment spacer 530 is smaller than the diameter d2 of opening end of hole part 313 on the first surface 310a side, and the alignment spacer 530 and hole part 313 are tapered in the fitting direction (reverse Z direction from the first surface 310a side to the second surface 310b side). Since the hole part 313 and the alignment spacer 530 has such structure, even if the vapor deposition mask 300 and substrate 104 is slightly misaligned, the hole part 313 and the alignment spacer 530 can be easily fitted to each other, and the position of the mask body 310 and substrate 104 can be self-aligned (self-aligned). Further, by fitting the hole part 313 and the alignment spacer 530, the distance between the vapor deposition mask 300 and the substrate 104 can be matched. Since the contact area between the hole part 313 and the alignment spacer 530 is large, dust generation from scratches of the alignment spacer 530 can be suppressed by dispersing the load applied to the alignment spacer 530, and productivity can be improved.
As described above, according to the deposition method using the vapor deposition mask 300 according to the present embodiment, by fitting the alignment spacer 530 and hole part 313, the deposition position accuracy and productivity can be improved. In addition to the normal optical alignment marker, the physical alignment marker including the alignment spacer 530 and the hole part 313 according to the present embodiment can further improve the deposition position accuracy.
The configuration of a vapor deposition mask according to an embodiment of the present invention will be described with reference to
In the present embodiment, the peripheral region 317A is provided with a hole part 313A which is a bottomed hole. During the vapor deposition, the hole part 313A is fitted with the alignment spacers of the substrate 104A to align the vapor deposition mask 300A with the substrate 104A. The hole part 313A corresponds to a part of peripheral region 317A that shields vapor deposition materials. The region other than the hole part 313A of peripheral region 317A also corresponds to the non-opening region 312A.
The depth of the hole part 313A in the thickness direction (reverse Z direction) of the mask body 310A is preferably in the range of 1/2 or more and 4/5 or less of the thickness of the mask body 310A. Since the depth of the hole part 313A is 1/2 or more of the thickness of the mask body 310A, the fitting between the hole part 313A and the alignment spacer is stabilized, and the positions of the mask body 310A and substrate 104A are easily aligned. Since the depth of hole part 313A is equal to or less than 4/5 of the thickness of the mask body 310A, it is possible to stably receive the load from the alignment spacer without penetrating the bottom portion of the hole part 313A (the second surface 310Ab of the mask body 310A). Such configuration of the hole part 313A allows the distances between the masking body 310A and substrate 104A to be matched.
In the present embodiment, the diameter of the opening end of the hole part 313A on the first surface 310Aa side is larger than the diameter of the closed end on the second surface 310Ab side. In other words, the hole part 313A has a taper structure in the direction in which the alignment spacer is fitted (i.e., in the reverse Z direction from the first surface 310Aa side to the second surface 310Ab side). Since the hole part 313A has such configuration, the hole part 313A and the alignment spacer are easily fitted to each other, and the positions of the masking body 310A and the substrate 104A are easily aligned with each other. Since the contacts area between the hole part 313A and the alignment spacer is large, dust generation from scratches of the alignment spacer can be suppressed by dispersing the load applied to the alignment spacer, and productivity can be improved. However, one embodiment of the present invention is not limited thereto, and the diameter of the opening end of hole part 313A on the first surface 310Aa side and the diameter of the closed end on the second surface 310Ab side may be substantially the same. Since hole part 313A has such configuration, peripheral region 317A can be narrowed.
In the present embodiment, hole part 313A has a cross shape in a planar view. The hole part 313A is a frustro-shaped bottomed hole with a cross-shaped opening end. However, one embodiment of the present invention is not limited thereto, and the hole part 313A may be T-shaped or L-shaped in the planar view. Since the hole part 313A has such configuration, the hole part 313A and the alignment spacer are hardly displaced when they are fitted, and the locations of the masking body 310A and substrate 104A are easily maintained. Further, since hole part 313A has corner portion, it is possible to align the positional deviation between the masks body 310A and substrate 104A in the rotational direction of the X-Z plane around the Y direction.
Since the hole part 313A according to the present embodiment has the above-described configuration, it is suitable for the main alignment in the vicinity of the periphery of the masked body 310A after the pre-alignment is performed. Therefore, in the present embodiment, the hole part 313A is provided in the vicinity of the periphery of the masking body 310A in planar view. However, one embodiment of the present invention is not limited thereto, and the hole part 313A may be provided near the center of the masking body 310A. In this embodiment, four hole part 313A are provided in the peripheral region 317A of the masking body 310A. However, one embodiment of the present invention is not limited thereto, and one or more hole part 313A may be provided in the peripheral region 317A, or may be provided in the non-opening region 312A of the mask pattern region 315A. By providing a plurality of hole part 313A, the accuracy of the deposition position can be further improved.
The hole part 313A according to the present embodiment preferably further combines the hole part 313 according to the first embodiment with the pre-alignment in the vicinity of the center of the masking body 310A. In planar view, the diameter of the hole part 313 located near the center of the mask body is preferably larger than the diameter of the hole part 313A located near the periphery of the mask. Here, the diameter of hole part in planar view indicates the smallest diameter of opening end of hole part in planar view. Since the hole part 313 disposed in the vicinity of the center and the hole part 313A disposed in the vicinity of the periphery have differing shapes and diameters, two stages of pre-alignment and main alignment can be performed, and the deposition position accuracy can be further improved.
As described above, according to the vapor deposition mask 300A of the present embodiment, since the hole part 313A having the above-described structures is included, when the vapor deposition mask 300A is fixed to the substrate 104A by a magnet or the like, the precision of the vapor deposition location and the productivity can be improved.
The method of manufacturing the vapor deposition mask 300A according to the embodiment is the same as the method of the first embodiment except that the height of the first insulating layer 450b is formed smaller than the height of the first insulating layer 450a, and therefore the description thereof will not be repeated.
In the vapor deposition method using the vapor deposition mask 300A according to the present embodiment, it is the same as that of the first embodiment except for the height of the alignment spacer 530A, and therefore, a repetitive description thereof is omitted. Since hole part 313A of the vapor deposition mask 300A according to the embodiment of the present invention disclosure has a bottomed hole, the height of the alignment spacer 530A is formed smaller than the height of the spacer 510A.
As described above, according to the vapor deposition method using the vapor deposition mask 300A according to the present embodiment, the alignment spacer 530A and the hole part 313A are fitted to each other, whereby the precision of the vapor deposition position and the productivity can be improved. In addition to the normal optical alignment marker, the physical alignment marker including the alignment spacer 530A and the hole part 313A according to the present embodiment can further improve the deposition position accuracy.
Each of the embodiments and the modification described above as an embodiment of the present invention can be appropriately combined and implemented as long as they do not contradict each other. Further, one embodiment of the present invention includes, as long as the gist of the one embodiment of present invention is provided, addition, deletion, or change of designs of constituent elements, or addition, omit, or change of condition of process, which are appropriately performed by a person skilled in the art based on the display device of the respective embodiments.
In this specification, the case of EL display device is mainly exemplified as the disclosed example, but other examples of application include any flat-panel type display device such as other self-luminous type display device, electronic paper type display device having electrophoretic elements and the like. In addition, one embodiment of the present invention can be applied from a medium-sized and small-sized to a large-sized, without any particular limitation.
Even if it is other working effects which differ from the working effect brought about by the mode of each above-mentioned embodiment, what is clear from the description in this Description, or what can be easily predicted by the person skilled in the art is naturally understood to be brought about by one embodiment of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-165584 | Sep 2019 | JP | national |
