KR20060058459A - Mask frame assembly, and method of manufacturing an organic electroluminesence device thereused - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a mask frame assembly in which a frame is bent in consideration of the deflection of a substrate, thereby improving pattern precision during deposition, and a method of manufacturing an organic light emitting display device using the same.

In order to achieve the above object, the present invention, the frame having an opening, a pattern portion that is supported in a state in which the tensile force is applied to the frame, the patterning is formed in a position corresponding to the opening is formed, the substrate to be deposited And a supporting mask, wherein at least a portion of the frame is curved to have a predetermined curvature with respect to the direction of the ground.

Description

Mask frame assembly, and method of manufacturing an organic electroluminescent device using the same {mask frame assembly, and method of manufacturing an organic electroluminesence device thereused}

1 is a schematic view of a deposition apparatus equipped with a mask frame assembly according to an embodiment of the present invention;

2 is an exploded perspective view of a mask frame assembly according to an embodiment of the present invention;

3 is a side view of the frame thereof;

4 is a cross-sectional view showing an alignment state of a mask frame assembly and a substrate;

5 is a cross-sectional view illustrating an example of an organic light emitting display device manufactured by the present invention.

<Brief description of the main parts of the drawing>

10: mask frame assembly 11: mask

12: frame 20: substrate

121: first sub frame 122: second sub frame

123: bent portion

The present invention relates to a deposition mask, and more particularly to a mask frame assembly that can be improved in precision, and a method of manufacturing an organic electroluminescent device using the same.

The electroluminescent device is a spontaneous light emitting display device and has attracted attention as a next generation display device because of its advantages of wide viewing angle, excellent contrast, and fast response speed.

The electroluminescent device is classified into an inorganic electroluminescent device and an organic electroluminescent device according to the material forming the light emitting layer. The organic electroluminescent device has excellent characteristics such as brightness, response speed, and the like as compared with the inorganic electroluminescent device. Its development has been actively underway since it has the advantage of being possible.

The organic electroluminescent device includes a first electrode formed in a predetermined pattern on a transparent insulating substrate, an organic film formed by vacuum deposition on the insulating substrate on which the first electrode is formed, and the organic electrode in a direction crossing the first electrode. Second electrodes formed on the upper surface of the film.

In fabricating the organic EL device configured as described above, the first electrode is usually made of indium tin oxide (ITO), and the patterning of the ITO is performed by photolithography.

By the way, the photolithography method as described above can be used at the stage before the organic film is formed, but there is a problem in its use after the organic film is formed. That is, the organic film is very vulnerable to moisture and must be thoroughly isolated from moisture even after its production process and production. Therefore, the photolithography method exposed to moisture in the resist stripping process and the etching process is not suitable for patterning the organic film and the second electrode layer.

In order to solve this problem, the organic light emitting material constituting the organic film and the material constituting the second electrode layer are frequently used in a vacuum deposition method using a mask having a predetermined pattern. In particular, although the second electrode layer may be patterned using a cathode separator, which is a predetermined isolation wall, it is known that the low molecular organic film is most suitably patterned by a vacuum deposition method using a deposition mask.

In the method of patterning an organic film or a 2nd electrode layer using a mask as mentioned above, the technique of patterning the organic film which is a light emitting layer is a very important technique in manufacturing a full color organic electroluminescent element.

Conventionally, the colorization method of the full-color organic electroluminescent element is known as a three-color independent deposition method in which each pixel of red (R), green (G), and blue (B) is independently deposited on a substrate, and blue light emission is used as a light emitting source. The color conversion method (CCM method) which provides a color conversion layer in a light extraction surface, the color filter system using a color filter using white light emission as a light emitting source, etc. are mentioned. Among them, the tricolor independent deposition method is the method that is attracting the most attention in that it shows excellent color purity and efficiency with a simple structure.

In the tricolor independent deposition method, red (R), green (G), and blue (B) pixels are independently deposited on a substrate using a deposition mask, wherein the deposition mask uses a material having a low coefficient of thermal expansion. Therefore, thermal deformation should not occur, and it should be a magnetic material when it adheres to the substrate with a magnet member.

On the other hand, the substrate used in the manufacturing process of the organic electroluminescent device is a large substrate is used to manufacture a plurality of organic electroluminescent devices in one process. However, since such a substrate is larger in size and is struck by gravity in the deposition process, there is a problem that it is difficult to increase the accuracy of the pattern when depositing through a mask as described above.

In order to compensate for the pattern precision generated in the deposition process, various methods have been proposed as follows.

Japanese Laid-Open Patent Publication No. 2001-247961 discloses a mask portion having partition walls partitioning a plurality of first openings by solving a problem of creep deformation of strips forming slots due to thermal expansion of the mask, and each of the above-mentioned. A mask having a screen portion including a plurality of second openings having an opening area smaller than the opening area of each of the first openings, and the plurality of second openings including magnetic materials disposed on the respective first openings of the mask portion. Is disclosed.

Japanese Laid-Open Patent Publication No. 2001-273979 discloses a structure of a magnetic mask, and Japanese Laid-Open Patent Publication No. 2001-254169 discloses a deposition mask in which a mask pattern corresponding to a deposition region is formed by masking a deposition portion in close contact with a deposition target. The frame has a mask pattern including a fine gap and a fine pattern portion that are difficult to support a predetermined dimension compared to the frame thickness, and has a structure in which the fine pattern portion of the mask pattern is supported by the fine ribs.

In addition, Japanese Laid-Open Patent Publication No. 2002-9098 is for solving the problem that the mask is partially expanded due to thermal expansion during deposition, thereby damaging the film already formed on the substrate. By using a support member for seating the mask on the stepped portion, the mask does not bend in a wave shape by the support member even when the mask is thermally expanded during film formation, and the magnetic member is formed on the other side of the mask during film formation. A pattern forming apparatus is disclosed in which a mask is brought into close contact with a substrate so that a gap is generated between the mask and the support member, thereby cooling the mask by using the gap.

Japanese Laid-Open Patent Publication No. 2002-8859 discloses a pattern forming apparatus for suppressing thermal expansion of a mask by heat during the film formation process, by forming a flow path inside a frame supporting the mask and circulating the coolant inside the flow path. It is.

Japanese Laid-Open Patent Publication Nos. 2000-48954, 2000-173769, 2001-203079, and 2001-110567 disclose metal masks further provided with reinforcement lines to prevent sagging of the mask shield between the mask and the frame.

By the way, all the above-mentioned methods are for preventing the deflection of the mask itself, and this deflection of the mask is relatively small compared to the deflection of the substrate. Therefore, there is a limit that cannot be a fundamental solution.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and in view of the sag of a substrate, a mask frame assembly having a curved frame may be introduced to improve pattern precision during deposition, and an organic light emitting display device using the same. It is an object to provide a manufacturing method.

In order to achieve the above object, the present invention, the frame having an opening, a pattern portion that is supported in a state in which the tensile force is applied to the frame, the patterning is formed in a position corresponding to the opening is formed, the substrate to be deposited And a supporting mask, wherein at least a portion of the frame is curved to have a predetermined curvature with respect to the direction of the ground.

In order to achieve the above object, the present invention also provides a method of manufacturing an organic light emitting display device in which a first electrode layer, an organic light emitting layer, and a second electrode layer are sequentially formed on a substrate, the organic light emitting layer and the second electrode layer. Formation is performed by depositing a mask frame assembly in the chamber with a mask frame assembly interposed therebetween, wherein the mask frame assembly is supported by a frame having an opening and a state in which tension is applied to the frame and corresponding to the opening. A patternable pattern portion is formed on the substrate, and includes a mask supporting a substrate to be deposited, wherein at least a portion of the frame is curved to have a predetermined curvature with respect to the direction of the paper. to provide.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a deposition apparatus equipped with a mask frame assembly 10 according to a preferred embodiment of the present invention.

Referring to the drawings, the mask frame assembly 10 according to the present invention is fixed on a cradle 32 installed in a vacuum chamber (not shown). In order to deposit the red, green, and blue thin films of the organic EL device, the mask frame assembly 10 is installed on the side corresponding to the deposition vessel 31 installed in the interior of the vacuum chamber 30, and the thin film is formed thereon. The substrate 20 to be formed is mounted. The support plate 33 is disposed on the substrate 20, and the magnet unit 34 is positioned on the support plate 33. As the magnet unit 34 pulls the mask 11, the substrate 20 is in close contact with the support plate 33 by the mask 11, and the mask 11 is also tightly fixed to the substrate 20.

In this state, the deposition material is evaporated by the operation of the deposition container 31 to deposit it on the substrate 20. The evaporated material is deposited on the substrate 300 through a pattern formed in the mask 11.

The present invention uses a mask frame assembly 10 as shown in FIGS. 2-4 when depositing organics or metals using such deposition apparatus.

Figure 2 is an exploded perspective view of the mask frame assembly according to an embodiment of the present invention, Figure 3 is a side view of the frame, Figure 4 is a cross-sectional view showing the alignment state of the mask frame assembly and the substrate.

Referring to the drawings, the mask frame assembly 10 according to an embodiment of the present invention includes a mask 11 and a frame 12.

The mask 11 has at least one unit masking pattern portion 111. Each unit masking pattern portion 111 is capable of depositing one element, and the patterning opening 112 is formed in a desired pattern.

The mask 11 is made of a magnetic thin plate, and may be made of nickel or an alloy of nickel and cobalt, and is preferably made of an alloy of nickel-cobalt that is easy to form a fine pattern and has a very good surface roughness. can do. In addition, the mask 11 having the patterning openings 112 may be formed by an electroforming method.

Such a mask 11 may be manufactured by an etching method as well, by using a photoresist to form a resist layer having a pattern of the patterning openings 112 in a thin sheet or to form a film having a pattern of the patterning openings 112. After attaching to the thin plate, it can be produced by etching the thin plate.

The mask 11 manufactured as described above is bonded to the frame 12 after applying a tensile force in the x-axis and y-axis directions in FIG. 2 with its edge fixed by a clamp or an adhesive. The frame 12 is formed in a hollow shape so as to support an edge portion except for a portion where each unit masking pattern portion 111 of the mask 11 is formed. As the bonding method, various methods such as bonding with an adhesive, laser welding, and resistance heating welding may be applied, but laser welding may be used in consideration of a change in precision.

The frame 12 is formed of a member having rigidity to support the mask 11, as shown in FIG. 2, a pair of first sub frames 121 parallel to each other and the first sub frame. It has a pair of second sub-frame 122 that connects both ends of the frame 121, respectively. The first sub frame 121 and the second sub frame 122 are integrally formed, but are not necessarily limited thereto, and may be separately manufactured and combined.

In a preferred embodiment of the present invention, the first sub-frame 121 and the second sub-frame 122 corresponds to the shape of the substrate 20, the length of the first sub-frame 121 is the second sub It may be greater than the length of the frame 122.

At this time, according to the present invention, as shown in Figure 3, a portion of the first sub-frame 121, for example, the central portion may be formed to be curved to have a predetermined curvature toward the direction of the ground. The curved portion 123 corresponds to the deflection of the substrate 20, and is formed to be deflected by the amount by which the substrate 20 is deflected. That is, the curvature of the curved portion 123 has a curvature corresponding to the curvature of the substrate 20 struck by gravity. Accordingly, the adhesion between the substrate 20 and the mask 11 can be further increased.

The curvature of the curved portion 123 of the first sub frame 121 may vary depending on the size of the substrate 20, and may be defined as follows.

In FIG. 4, the length of the long side of the substrate 20 is x1, the depth struck by the gravity of the substrate 20 is y1, and the radius of curvature of the portion struck in the approximately center portion of the substrate 20 is r1. In this regard, r1 can be obtained by the following formula.

r1 ² = (r1-y1) ² + (x1 / 2) ²

Since the radius of curvature of the curved portion of the substrate 20 and the radius of curvature of the curved portion 123 of the frame 12 coincide with each other, the radius of curvature of the curved portion 123 of the frame 12 is r2. The radius of curvature of the bent portion 123 of the frame 12 can be obtained by the above equation by the relationship of r1.

4, the length of the first sub frame 121 is referred to as x2, the bent depth of the first sub frame 121 is referred to as y2, and the bent portion 123 of the first sub frame 121 is referred to as FIG. 4. When the radius of curvature of r2 is r2, r2 can be obtained by the following equation in the same manner.

r2 ² = (r2-y2) ² + (x2 / 2) ²

As the frame 12 is bent in advance in response to the deflection of the substrate 20, the adhesion between the substrate 20 and the mask 11 can be further improved, and the pattern precision can be further improved.

In addition, when depositing using the deposition apparatus as shown in FIG. 1, the magnet unit 34 may not be used, and thus, the cost reduction effect may be increased, and the mask 11 may be forcibly pulled onto the substrate 20. As a result, the films previously formed on the substrate 20 can be prevented from being damaged by the mask 11 surface.

The mask frame assembly 10 may be used for depositing an organic light emitting layer or an upper electrode layer of an organic light emitting display device.

Next, a method of manufacturing an organic EL device using the deposition mask as described above will be described.

5 is a cross-sectional view of an active matrix organic organic light emitting display device manufactured using the mask frame assembly 10 of the present invention.

Referring to FIG. 5, the active mattress type organic light emitting display device is formed on a substrate 20. The substrate 20 may be formed of a transparent material such as glass or plastic. The buffer layer 21 is formed on the substrate 20 as a whole.

On the buffer layer 21, a TFT 40, a capacitor 50, and an organic EL device 60 as shown in FIG. 5 are formed.

On the upper surface of the buffer layer 21, semiconductor active layers 41 arranged in a predetermined pattern are formed. The semiconductor active layer 41 is filled with the gate insulating film 22. The active layer 41 may be formed of a p-type or n-type semiconductor.

The gate electrode 42 of the TFT 40 is formed on the top surface of the gate insulating layer 22 to correspond to the active layer 41. An interlayer insulating film 23 is formed to cover the gate electrode 42. After the interlayer insulating layer 23 is formed, a portion of the active layer 41 is exposed by etching the gate insulating layer 22 and the interlayer insulating layer 23 by an etching process such as dry etching to form a contact hole.

Next, a source / drain electrode 43 is formed on the interlayer insulating film 23, and is formed to contact the active layer 41 exposed through the contact hole. A passivation layer 24 is formed to cover the source / drain electrodes 43, and a portion of the drain electrode 43 is exposed through an etching process. An additional insulating layer may be further formed on the passivation layer 24 to planarize the passivation layer 24.

The organic EL device 60 emits red, green, and blue light according to the flow of current to display predetermined image information. The organic light emitting device 60 displays the first electrode 61 on the passivation layer 24. Form. The first electrode 61 is electrically connected to the drain electrode 43 of the TFT 40.

In addition, an insulating layer 25 is formed to cover the first electrode 61. After the predetermined opening 64 is formed in the insulating film 25, the organic light emitting film 63 is formed in the region defined by the opening 64. The second electrode 62 is formed on the organic emission layer 63.

As shown in FIG. 5, the insulating layer 25 is a pixel defining layer that divides each pixel. The insulating layer 25 is formed of an organic material, and particularly, a protective layer on a surface of the substrate on which the first electrode 61 is formed. The surface of 24 is planarized.

The first electrode 61 and the second electrode 62 are insulated from each other, and light is emitted by applying voltages of different polarities to the organic light emitting layer 63.

The organic light emitting layer 63 may be a low molecular weight or high molecular organic material. When the low molecular weight organic material is used, a hole injection layer (HIL), a hole transport layer (HTL), and an emission layer (EML) are emitted. ), An electron transport layer (ETL), an electron injection layer (EIL), or the like, may be formed by stacking a single or a complex structure, and the usable organic material may be copper phthalocyanine (CuPc). , N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), Various applications are possible, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic materials can be formed by a vacuum deposition method using the deposition apparatus as shown in FIG. 1 and the mask frame assembly of the present invention.

The organic light emitting film as described above is not necessarily limited thereto, and various embodiments may be applied. The first electrode 61 may function as an anode electrode, and the second electrode 62 may function as a cathode electrode. Of course, the first electrode 61 and the second electrode 62 may be used. ) May be reversed. The first electrode 61 may be patterned to correspond to the area of each pixel, and the second electrode 62 may be formed to cover all the pixels.

The first electrode 61 may be provided as a transparent electrode or a reflective electrode, and when used as a transparent electrode, may be formed of ITO, IZO, ZnO, or In 2 O 3, and when used as a reflective electrode, Ag, Mg, After the reflective layer is formed of Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, a compound thereof, or the like, a transparent electrode layer may be formed thereon with ITO, IZO, ZnO, or In 2 O 3. The first electrode 61 is formed by a sputtering method or the like and then patterned by a photolithography method or the like.

Meanwhile, the second electrode 62 may also be provided as a transparent electrode or a reflective electrode. When the second electrode 62 is used as a transparent electrode, since the second electrode 62 is used as a cathode, a metal having a small work function, namely, Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and compounds thereof are deposited to face the organic light emitting film 63, and thereafter, ITO, IZO, ZnO, In2O3, or the like. The auxiliary electrode layer and the bus electrode line can be formed. When used as a reflective electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and compounds thereof are formed by depositing the entire surface. At this time, the deposition may be formed by using the mask frame assembly of the present invention, as in the case of the organic light emitting film 63 described above.

In addition to the above, the present invention can also be used for deposition of organic TFTs and the like of organic TFTs, and can be applied to film forming processes of various other materials.

According to the present invention as described above, the following effects can be obtained.

First, it is possible to improve the pattern precision for the effective deposition area where the user wishes to deposit.

Second, when depositing several devices at the same time in a single process to improve the precision of the total pitch, it is possible to reduce the failure rate.

Third, the alignment position between the deposition mask and the substrate can be exactly matched.

Fourth, even when the mask is applied with tensile force, the pattern precision can be prevented from deteriorating.

In the present specification, the present invention has been described with reference to limited embodiments, but various embodiments are possible within the spirit of the present invention. And although not described, equivalent means will be included in the present invention. Therefore, the true scope of the present invention will be defined by the claims below.

Claims (10)

A frame having an opening; And And a mask that is supported while the tensile force is applied to the frame, and that is patternable to form a pattern at a position corresponding to the opening, and supports a substrate to be deposited. And at least a portion of the frame is curved to have a predetermined curvature with respect to the direction of the ground. The method of claim 1, And a curvature of the bent portion of the frame corresponds to a curvature of the deposited substrate by gravity. The method of claim 2, When the length of the long side of the substrate to be deposited is x1, the length of the substrate to be sag due to gravity is y1, and the radius of curvature of the bent portion of the frame is r, r satisfies Equation 1 below. Mask frame assembly, characterized in that. [Equation 1] r ² = (r-y1) ² + (x1 / 2) ² The method of claim 1, The frame, A pair of first sub-frames parallel to each other; And A pair of second sub-frames each of which is connected to an end of the first sub-frame, and whose length is equal to or less than the length of the first sub-frame; And a curved portion of the frame is the first sub frame. The method of claim 4, wherein When the length of the first sub frame is x2, the bent depth of the first sub frame is y2, and the radius of curvature of the bent portion of the first sub frame is r, r is expressed by Equation 2 below. Mask frame assembly, characterized in that. [Equation 2] r ² = (r-y2) ² + (x2 / 2) ² 1. A method of manufacturing an organic light emitting display device in which a first electrode layer, an organic light emitting layer, and a second electrode layer are sequentially formed on a substrate. The organic light emitting layer and the second electrode layer are formed by depositing a mask frame assembly on the substrate in a chamber. The mask frame assembly, A frame having an opening; And And a mask that is supported while the tensile force is applied to the frame, and that is patternable to form a pattern at a position corresponding to the opening, and supports a substrate to be deposited. And at least a portion of the frame is curved to have a predetermined curvature with respect to the direction of the paper surface. The method of claim 6, And a curvature of the bent portion of the frame corresponds to a curvature of the deposited substrate by gravity. The method of claim 7, wherein When the length of the long side of the substrate to be deposited is x1, the length of the substrate to be sag due to gravity is y1, and the radius of curvature of the bent portion of the frame is r, r satisfies Equation 1 below. A method of manufacturing an organic light emitting display, characterized in that [Equation 3] r ² = (r-y1) ² + (x1 / 2) ² The method of claim 6, The frame, A pair of first sub-frames parallel to each other; And A pair of second sub-frames each of which is connected to an end of the first sub-frame, and whose length is equal to or less than the length of the first sub-frame; And a curved portion of the frame is the first sub frame. The method of claim 9, When the length of the first sub frame is x2, the bent depth of the first sub frame is y2, and the radius of curvature of the bent portion of the first sub frame is r, r is expressed by Equation 2 below. A method of manufacturing an organic electroluminescent display, characterized in that it is satisfied. [Equation 4] r ² = (r-y2) ² + (x2 / 2) ²

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