KR101780385B1 - Oled encapsulation structure and manufacturing method thereof - Google Patents

Abstract

In order to realize an organic light emitting diode encapsulating structure having a low process temperature that does not damage the organic film inside the organic light emitting diode device and excellent blocking ability against penetration of moisture and air, Forming a heating layer; Forming a preliminary encapsulant composed of a mixture of a low melting point alloy and a polymer organic substance on the heat generating layer; Separating the preliminary sealing material into a low-melting-point alloy layer and a polymer organic material layer by using a Joule heat generated by applying a current to the heating layer; And curing the polymer organic material layer.

Description

TECHNICAL FIELD [0001] The present invention relates to an OLED encapsulation structure,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure and a manufacturing method thereof, and more particularly, to an organic light emitting diode sealing structure and a manufacturing method thereof.

Organic light emitting diodes (OLEDs) have attracted much attention as next generation display devices because they have many advantages such as self-luminescence and high reaction speed. One of the major obstacles to device performance in organic light emitting diodes is the presence of black spots, which are known to be responsible for the penetration of moisture and / or air into the device. To prevent this, an effective sealing technique is needed to prevent penetration of moisture and air.

As a representative encapsulation technique of an organic light emitting diode, there is a method of using a UV curable epoxy together with a moisture absorber. In this curing method using only epoxy, moisture and air penetration can not be completely blocked. Glass frit is used as an encapsulating material and a technique of sealing with a laser is widely used. This method has an advantage that it has excellent ability to block moisture and air infiltration. However, since the generated temperature is high, it can be used only for a glass substrate.

Recently, the best sealing method is a thin film encapsulation (TFE) technology that continuously deposits organic and inorganic thin film layers. For example, there is a thin-film encapsulation technique in which four layers of a polymeric polymer, AlO _x , are repeatedly deposited, and TFE techniques in which SiO ₂ and SiN _x are repeatedly deposited are studied. In addition, studies on the lifetime increase of CF _x and Si ₃ N ₄ layers are under way. In addition, studies on the characteristics and life span of PVAC, PMMA, and CYTOP polymer barriers have been conducted, and studies on TFE technology through repeated deposition of Al ₂ O ₃ and polymer polymers have been conducted. However, such a method may cause serious problems in reliability if pinholes or cracks are not completely removed during the deposition process, and the moisture shielding force in the direction perpendicular to the thin film sealing layer is good, but the shielding effect in the parallel direction It is showing the limit.

In conclusion, there is still a need for a new encapsulation technology that has a low process temperature that does not damage the organic film inside the device, and has excellent blocking ability against moisture and air infiltration.

An object of the present invention is to provide an organic light emitting diode encapsulating structure having a low process temperature that does not damage the organic film inside the organic light emitting diode device and has excellent blocking ability against penetration of moisture and air, and a manufacturing method thereof. However, these problems are exemplary and do not limit the scope of the present invention.

An organic light emitting diode encapsulating structure according to one aspect of the present invention is provided. Wherein the organic light emitting diode encapsulating structure is a pattern locally disposed on a substrate, the heat emitting layer being capable of generating joule heat by an applied electric current; A low melting point alloy (LMPA) layer formed on the heating layer; And a polymer organic material layer surrounding at least a part of the heat generating layer and the low melting point alloy layer.

In the organic light emitting diode encapsulating structure, the substrate may include a lower substrate and an upper substrate spaced apart from each other, wherein the organic light emitting diode device is disposed on at least one substrate of the lower substrate and the upper substrate, Wherein the heat generating layer is disposed apart from the organic light emitting diode device and the low melting point alloy layer is interposed between the lower substrate and the upper substrate so as to block penetration of moisture and / or air, The both sides of the alloy layer may be sealed and adhered to the substrate by being cured while continuing from the lower substrate to the upper substrate.

In the organic light emitting diode encapsulating structure, the heat generating layer may contain at least one selected from the group consisting of Mo, Ti, Ni and Al, and the low melting point alloy layer may contain at least one selected from Sn, Cd, In and Bi have.

A method for manufacturing an organic light emitting diode encapsulating structure according to another aspect of the present invention is provided. A method of fabricating an organic light emitting diode encapsulation structure includes: a first step of forming a heating layer that is a pattern locally disposed on a substrate; A second step of forming a preliminary sealing material composed of a mixture of a low melting point alloy and a polymer organic substance on the heating layer; And a third step of phase-separating the preliminary sealing material into a low-melting-point alloy layer and a polymer organic material layer using a Joule heat generated by applying a current to the heating layer. And a fourth step of curing the polymer organic material layer after the third step.

In the method for manufacturing an organic light emitting diode encapsulating structure, the phase separation may be performed prior to the curing step.

The method of manufacturing an organic light emitting diode encapsulation structure according to claim 1, wherein the first step further comprises forming a sacrificial layer on the heating layer, wherein the sacrificial layer is formed by the joule heat generated in the third step At least some of the materials react with at least some of the materials constituting the low melting point alloy layer to form a compound, so that the low melting point alloy layer may have selective wetting with the sacrificial layer. In this case, in the third step, the low melting point alloy layer is formed in contact with the sacrificial layer, and the polymer organic material layer may be formed on both sides of the low melting point alloy layer.

The first step of the manufacturing method may further include forming an insulating layer interposed between the heating layer and the sacrificial layer.

According to the embodiments of the present invention described above, an organic light emitting diode encapsulating structure having a low process temperature that does not damage the organic film inside the organic light emitting diode device and excellent blocking ability against penetration of moisture and air, and a manufacturing method thereof Can be provided. Of course, the scope of the present invention is not limited by these effects.

1 is a flowchart illustrating a method of manufacturing an organic light emitting diode encapsulation structure according to an embodiment of the present invention.
2A and 2B are cross-sectional views schematically illustrating a manufacturing method according to an embodiment of the present invention and an organic light emitting diode encapsulating structure implemented thereby.
3 is a state diagram of Sn-Cu for illustrating a sacrifice layer applied to a method of manufacturing an organic light-emitting diode encapsulation structure according to an embodiment of the present invention.
4A and 4B are DSC curves of an epoxy and a low melting point alloy layer constituting a preliminary encapsulant applied in the method of manufacturing an organic light emitting diode encapsulating structure according to an embodiment of the present invention.
FIG. 5 is a graph illustrating a temperature measured in the process of manufacturing the organic light emitting diode encapsulating structure according to an embodiment of the present invention. Referring to FIG.
FIGS. 6A and 6B are photographs showing changes in the structure of the organic light emitting diode encapsulant before and after heating the joule heat in the process of manufacturing the organic light emitting diode encapsulating structure according to an embodiment, by an optical microscope.
7 is a scanning electron microscope (SEM) image of the organic light emitting diode encapsulating structure after the curing step in the process of manufacturing the organic light emitting diode encapsulating structure according to an embodiment of the present invention.
8A to 8C are SEM mapping images after Joule heating according to various thicknesses of a sacrificial layer applied to a method of manufacturing an organic light emitting diode encapsulating structure according to an embodiment of the present invention.
9A is a view for explaining factors for defining a phase separation characteristic in a method of manufacturing an organic light emitting diode encapsulating structure according to an embodiment of the present invention.
9B is a graph illustrating the phase separation characteristics according to the epoxy content in the method of manufacturing the organic light emitting diode encapsulating structure according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, at least some of the components may be exaggerated or reduced in size for convenience of explanation. Like numbers refer to like elements throughout the drawings.

It is to be understood that throughout the specification, when an element such as a layer or a region is referred to as being "on" another element, the element may be directly "on" It will be understood that there may be other intervening components. On the other hand, when an element is referred to as being "directly on" another element, it is understood that there are no other elements intervening therebetween.

The present inventors have found that a low melting point alloy line which prevents moisture and air from penetrating by inducing phase separation by heating a sealing material obtained by mixing a low melting point alloy (LMPA) and epoxy in a heat treatment furnace, A double-line structure of the line is proposed. However, since the temperature of about 180 ° C. is applied to the entire organic light emitting diode device, it may be necessary to further lower the heat treatment temperature to 100 ° C. or less so as not to damage the organic film inside the device.

In order to accomplish this, a method of locally heating only an encapsulation region using Joule heating is proposed as a manufacturing method of an organic light emitting diode encapsulation structure according to an embodiment of the present invention. Joule heating can be understood as a method of applying electric current to a conductor to generate heat corresponding to the Joule's law and heating it by using it.

Hereinafter, in order to solve the problem of excessive heat being applied to the organic material inside the device in a new sealing technique of heating a mixed material of a low-melting-point alloy and a polymer organic material, a technique of locally heating the sealing area using Joule heating Will be described in detail.

FIG. 1 is a flowchart illustrating a method of manufacturing an organic light emitting diode encapsulating structure according to an embodiment of the present invention. FIGS. 2a and 2b are sectional views sequentially illustrating a manufacturing method according to an embodiment of the present invention.

Referring to FIGS. 1, 2A, and 2B, a method of fabricating an organic light emitting diode encapsulating structure according to an exemplary embodiment of the present invention includes steps of preparing a substrate (S10) (S20); (S30) forming a preliminary encapsulant 30 composed of a mixture of a low melting point alloy 32 and a polymer organic substance 34 on the heat generating layer 20; Phase separation of the preliminary encapsulant 30 into the low-melting-point alloy layer 32a and the polymer organic layer 34a using the joule heat generated by applying the current to the heat generating layer 20 (S40); And curing the polymer organic material layer 34a (S50).

First, a substrate will be described in a method of manufacturing an organic light emitting diode encapsulating structure according to an embodiment of the present invention. The substrate may comprise a glass substrate or a substrate of flexible material. For example, the substrate may include a lower substrate 10a and an upper substrate 10b that are spaced apart from each other. In this case, at least one of the lower substrate 10a and the upper substrate 10b An organic light emitting diode device (device) may be disposed on the substrate. The step in which the organic light emitting diode device is mounted on the substrate may be included in any one of the steps S10 to S50 described above or may be performed separately before or after the steps described above.

The substrate on which the heating layer 20 is formed in step S20 of forming the heating layer 20 locally disposed on the substrate may be formed on the lower substrate 10a and the upper substrate 10b, Not shown) may be mounted. In this case, the heat generating layer 20 and the organic light emitting diode device may be spaced apart from each other on the substrate on which the organic light emitting diode device and the heat generating layer 20 are mounted.

According to the modified embodiment, the substrate on which the heating layer 20 is formed in the step S20 of forming the heating layer 20, which is a pattern locally disposed on the substrate, includes the lower substrate 10a, (Not shown) may not be mounted on the organic light emitting diode 10b. In this case, the substrate on which the organic light emitting diode device and the heat generating layer 20 are disposed are different from each other, so that the heat generating layer 20 and the organic light emitting diode devices can be disposed apart from each other.

According to such a configuration, since the heat generating layer 20 and the organic light emitting diode elements are disposed apart from each other, the possibility that the local joule heat generated in the heat generating layer 20 affects the inside of the organic light emitting diode element becomes low.

In step S30 of forming the preliminary sealing material 30 composed of the mixture of the low melting point alloy 32 and the polymer organic material 34 on the heating layer 20, the low melting point alloy 32, which is the metal particles, 70% to 99.9% of the ash 30 may be constituted, and the polymer organic material 34 may be constituted of 0.1% to 30% of the preliminary encapsulant 30. The amount of the polymer organic material 34 that can be mixed with the low melting point alloy 32 as the metal particles is 0.1%, and if the amount of the polymer organic material 34 is too large, it may affect the organic light emitting diode It may be preferable to be within 30%.

Particularly, when the polymer organic material 34 is epoxy-based, it can be classified into a thermosetting type and a UV-curing type. In case of the UV curing type, the viscosity is low even when the mixing ratio of the polymer organic material 34 is 1% ), It may be preferable that the thickness is kept at 1% or less. In this case, strictly speaking, the low-melting alloy 32, which is the metal particle, can constitute 99% to 99.9% of the preliminary encapsulant 30 and the polymer organic material 34 can constitute 0.1% To 1%.

In the present invention, the low melting point alloy 32 is an alloy of a metal material practically used at a melting point of Pb melting at 327.4 占 폚, and may contain at least any one selected from Sn, Cd, In, Bi and Pb A Sn-Bi alloy, a Pb-Sn alloy, a Pb-Sn-Sb alloy, a Pb-Ag-Sn alloy or the like can be used. . In this case, the heat generating layer 20 may contain at least one selected from the group consisting of Mo, Ti, Ni and Al.

If the Joule heat is applied to the preliminary sealing material 30 in the step S40, the low melting point alloy 32, which is the metal particles constituting the preliminary sealing material 30 by self-organization of the low melting point metal, And the polymer organic material 34 constituting the preliminary sealing material 30 is separated into the polymer organic material layer 34a by phase separation with the alloy layer 32a. The low-melting-point alloy layer 32a serves as a barrier for protecting the organic light-emitting diode device from moisture and / or oxygen, and the polymeric organic layer 34a serves as a bonding strength between the substrate and the low melting point alloy layer 32a Voids or small cracks present at the interface can be covered. The polymer organic compound layer 34a may be adhered to the substrates 10a and 10b by sealing both side portions of the low melting point alloy layer 32a and curing while continuing from the lower substrate 10a to the upper substrate 10b.

Hereinafter, the sacrifice layer 24 introduced to control the line width of the low melting point alloy layer 32a will be described.

Step S20 of forming the heating layer 20 as a pattern locally disposed on the substrate includes forming the sacrifice layer 24 on the heating layer 20 after forming the heating layer 20 can do. The sacrificial layer 24 is made of a material having a low melting point alloy layer 32a having selective wetting so that the fluidity of the low melting point alloy 32 which is phase separated in the preliminary sealing material 30 is limited, The line width of the alloy layer 32a can be controlled. For example, by the Joule heat generated in the heating layer 20, at least some of the materials constituting the sacrificial layer 24 react with at least some of the materials constituting the low melting point alloy layer 32a to form a compound , The low melting point alloy layer 32a may have selective wettability with the sacrificial layer 24.

The sacrificial layer 24 is a metal layer having excellent wetting properties, and may be made of, for example, Cu. The sacrificial layer 24 may have a thickness of 1000 angstroms or more. When the sacrifice layer 24 is 1000 angstroms or less, it can not serve as a sacrificial layer for self-organization due to Cu-Sn reaction or the like, and can have fluidity. However, the sacrificial layer 24 of the present invention is not limited to the Cu layer, and may be formed of various materials. In one example, the sacrificial layer 24 may contain any one selected from Cu, Mo, Cr, Ni, and Al.

Further, the sacrificial layer 24 may be additionally formed on the substrate on which the heating layer 20 is not disposed, of the lower substrate 10a and the upper substrate 10b. In this case, the sacrifice layer 24 is disposed above and below the low melting point alloy layer 32a to effectively restrict the fluidity of the low melting point alloy 32 that is phase separated from the preliminary sealing material 30, It is possible to more precisely control the line width. On the other hand, the gap between the upper and lower sacrificial layers 24 may be 3 mm to 100 m. At this time, the lower limit of 100 μm is determined in consideration of the minimum space that the polymer organic material 34 can occupy, and the upper limit of 3 mm is determined in consideration of the distance at which the low melting point alloy 32, which is metal particles, . However, the technical idea of the present invention is not limited thereto, and may be variously determined in consideration of the material of the sacrificial layer 24 and the preliminary encapsulant 30.

Hereinafter, exemplary embodiments of the present invention for implementing the organic light-emitting diode encapsulating structure and the manufacturing method thereof will be described. It should be understood, however, that the invention is not limited to the disclosed exemplary embodiments, but is capable of other various forms of implementation. The following examples are intended to be illustrative of the present invention, Is provided to fully inform the user.

First, a seal pattern structure designed to generate joule heat will be described with reference to FIG. 2A. A base layer 25 having a thickness of several angstroms was formed in the form of a line in the form of a multilayer thin film pattern along the periphery of the substrate 10a and a bag made of a mixture of Sn-58Bi (32) and epoxy (34) The material 30 was applied by screen printing to complete the sealing pattern. When a current is applied to the multilayer thin film pattern to generate joule heat, phase separation occurs in the encapsulant 30 due to the heat, so that a double line as shown in FIG. 2B is formed and the upper substrate 10b and the lower substrate (10a). In the enlarged circle, the structure of the multilayer thin film pattern used as the underlayer is shown. Each production method will be described in detail as follows.

Fabrication of multilayer thin film pattern

Specifically, the multilayer thin film pattern includes a heating layer 20 for generating joule heat by flowing electric current, an insulating layer 22 for preventing sparking and electrical insulation, and a sacrificial layer 24 for improving phase separation and wettability. Structure. In the case of the heating layer 20, a material having a high electrical resistance should be selected to increase the amount of joule heat generation. In the case of the sacrificial layer 24, a material excellent in wetting with the Sn-58Bi material can be selected . The heating layer 20 and the sacrificial layer 24 are electrically insulated from each other to exert their respective independent functions.

Heating layer

The melting temperature of the Sn-58Bi material, which is the low melting point alloy (32) selected in this Experiment Example, was 139 占 폚, and the UV curable epoxy was used as the polymer organic material (34). UV hardening type epoxy was used without thermosetting epoxy due to insufficient amount of heat to cure Si series thermosetting epoxy by using Joule heat.

In this experimental example, a pattern of Mo, Ti, Ni, Al or the like was formed on the heating electrode 20 to compare the temperature rising behavior due to Joule heat generation. In the case of a material having a low resistivity, the thickness of the electrode pattern must be made thin in order to secure a certain line resistance required for the joule heat generation, thereby causing problems such as disconnection of the electrode frequently. As a result of the experiment, it was confirmed that the Sn-58Bi material can be stably fused in the shortest time in the case of Mo, and thus it was selected as the material constituting the heat generating layer 20. As the deposition condition of Mo, Ar gas was injected by DC sputtering method and coated at a thickness of 1,500 Å under a pressure of 500 mTorr.

Insulating layer

Since the surface of the exothermic electrode 20 often has a pinhole or a pore, sparks often occur when a current is applied. Therefore, the insulating layer 22 is coated on the surface of the exothermic electrode 20 to suppress the generation of sparks Respectively. Another reason for coating the insulating layer 22 is to maintain electrical insulation between the heating electrode 20 and the sacrificial layer 24.

As the material of the insulating layer 22, SiO ₂ was used. As a film forming condition, 150 W of power was applied by RF sputtering, and Ar gas was applied to coat the film to a thickness of 2,000 Å under a pressure of 500 mTorr.

Sacrificial layer

In this experiment, a Sn-58Bi composition with a melting temperature of 139 ° C was selected as a low-melting alloy (32). A sacrificial layer (24) capable of reacting with Sn-58Bi so that phase separation of Sn- ) Was introduced. FIG. 3 shows the state of Sn-Cu. It can be seen that Cu and Sn compounds are formed even at 100 ° C or lower. Therefore, in this experimental example, Cu was used as the sacrificial layer 24 to impart selective wettability to Sn-58Bi, which is a low melting point alloy (32) composition.

As the deposition conditions of Cu, Ar gas was injected by DC sputtering, and the coating was performed under a pressure of 500 mTorr. The coating thickness was varied to 1,500, 3,000 and 6,000 Å. The multilayer thin film pattern thus formed was patterned in the form of a line having a width of 0.5 mm and a thickness of several angstroms along the periphery of the substrate using photolithography and an aluminum etchant.

Manufacturing and printing of encapsulant

The sealing material 30 used a mixture of Sn-58Bi, which is a low melting point alloy 32, and an epoxy, which is a polymer organic material 34. [ The role of Sn-58Bi is to form a tight seal line to provide barrier against penetration of moisture and air. In this example, a Sn-58Bi composition with a melt temperature of 139 ° C was selected. The epoxy reinforces the adhesive force between the substrates 10a and 10b and plays a role of pinholes and voids existing in the sealing line.

First, comparative experiments were conducted for thermosetting and UV curing epoxy for the selection of suitable epoxy. FIGS. 4A and 4B are DSC curves for Sn-58Bi and thermosetting Si epoxy. As shown in FIG. 4B, the exothermic peak at 180.degree. C. and the endothermic peak at 139.degree. As a result of the basic experiment using Joule heating, it was judged that it is not effective to supply the amount of heat required for hardening by the Joule heating method in case of the thermosetting epoxy. On the other hand, in the case of the UV curable epoxy, the UV curable epoxy is selected in this experiment because it has a property of curing by reacting with UV more sensitively than heat. In order to stir the Sn-58Bi and the epoxy mixture, the mixture was stirred at 400 RPM for 20 minutes using a ball mill. The UV curing epoxy used in this experiment was one-pack type, and no curing agent was used.

The encapsulant 30 thus prepared was applied to the multilayer thin film pattern made of the base layer 25 by screen printing. A Cu pattern was formed on the upper glass substrate 10b as an additional sacrificial layer 24 in the same form as the foundation layer 25 for smooth phase separation. The printing line width of the sealing material 30 was designed to be equal to 0.5 mm, which is the line width of the multilayer thin film pattern, and the printing conditions were ST # 325 screen mask. When the content of epoxy in the mixture was 1.0 wt% or more, the viscosity of the mixture became very thin and was not suitable for printing using a screen mask. Therefore, the epoxy content was varied to 0.2, 0.5 and 1.0 wt% The effect was investigated.

When the epoxy is exposed to ultraviolet rays, the epoxy cures before the phase separation of Sn-58Bi and epoxy. In order to prevent this, all processes from preparation to printing of the mixture proceed under yellow fluorescent lamps blocked with ultraviolet rays.

Hereinafter, the results shown by the above-described experimental method will be discussed and explained.

Formation of double line by Joule heating

The current was applied to the encapsulated pattern using the power supply, and Joule heat was generated. Since the Mo thin film electrode used as the heating layer 20 tends to be damaged when the power of 6 W or more is applied, the experiment was performed by applying 5.8 W in this experiment. The thermocouple equipment DT-9828 and K-type thermocouple, which can measure the temperature once per second, were used to confirm the temperature of the joule heat generated in the encapsulation pattern.

FIG. 5 shows the temperature change with time when 5.8 W is applied. The temperature measurement is based on the temperature (a) at the sealing line and the temperature (b) at the position 5 mm from the sealing line on the glass substrate Respectively. The temperature of the sealing line was increased to 139 ° C above the melting temperature of Sn-58Bi after 60 seconds. The temperature of the glass substrate, which was 5 mm away from the sealing line, was measured at about 82 ° C (b). Under these conditions, it was judged that the organic light emitting layer inside the device would not be thermally damaged when fabricating the organic light emitting diode device. Therefore, in this experiment, the Joule heating condition was fixed by maintaining the condition at 5.8 W for 60 seconds.

Figs. 6A and 6B show changes in the encapsulation pattern structure before and after Joule heating with an optical microscope. As shown in FIG. 6A, the mixture 30 was printed so as to be wider than the line width of the pattern of the underlayer 25 (line width of the pattern indicated by the dotted line) before the Joule heating. However, after the Joule heating, It can be seen that the pattern is similar to the line width of the underlying layer 25 pattern. This means that the Sn-58Bi was melted by Joule heat and the molten Sn-58Bi was rearranged along the pattern of the sacrificial layer (24) under the encapsulant. Also, as shown in FIG. 6B, it can be seen that a double line structure is formed in a state where the epoxy component is separated from the pattern of the ground layer 25.

UV hardening of epoxy

In the structure of FIG. 6B, double lines were formed. However, it was found that the adhesive strength between the two substrates 10a and 10b was not secured yet. This is because the current state is that Sn-58Bi is melted and separated into double lines along the underlying layer 25 pattern, but the epoxy is still not cured. Therefore, after the phase separation, a two-step process of stabilizing the double line structure through epoxy curing can be performed to ensure adhesion.

The present inventor has conducted an experiment to obtain an adhesive force using a heating furnace. In this experiment, a two-step process was performed through UV curing, which is a method favorable for protecting devices. UV curing was carried out for 10 seconds with an ultraviolet lamp having wavelengths of 4.8 W and 365 nm.

FIG. 7 shows a cured seal pattern observed with a scanning electron microscope, showing a state in which Sn-58Bi was gathered along the encapsulation pattern and the epoxy was pushed out to the side and phase separation was obtained. Also, It can be seen that the glass substrate is well bonded.

Optimization of Cu thickness in underlayer

In this experiment, Cu was disposed as the sacrificial layer 24 at the top of the foundation layer 25 composed of three layers. As described in the state diagram of FIG. 3, when the Sn-58Bi mixture is printed on the Cu layer, It is used for the purpose of facilitating the phase separation through the reaction with Cu and the reaction product. As described above, since the reaction between Sn and Cu is the main cause of the phase separation in the present experimental example, if the sacrifice layer 24 is completely destroyed before the phase separation is completed, the phase separation can not be performed properly.

Therefore, in order to determine the minimum thickness required for the sacrificial layer 24, the thickness of the Cu layer was changed to 1,500 Å, 3,000 Å, and 6,000 Å using a sputtering machine. 8A is an SEM mapping image when the thickness of the Cu layer is 1,500 ANGSTROM, and no Cu was found at the interface because the entire amount of Cu diffused into the mixture due to the intermetallic reaction. In contrast, in FIGS. 8B and 8C in which the thicknesses of the Cu layers are 3,000 ㅕ and 6,000 Å, respectively, it can be seen that a part of Cu remains at the interface. Therefore, although both of the above conditions were valid for the purpose of this experiment, considering the economical efficiency, it was found to be appropriate to set the thickness of the Cu layer to 3,000 Å.

Optimize mixture content

When the content of epoxy in the mixture (30) was 1.0 wt% or more, the viscosity of the mixture (30) became very thin and was not suitable for printing using a screen mask. Therefore, the epoxy content was varied to 0.2, 0.5 and 1.0 wt% The effect was investigated.

FIG. 9A shows the phase separation of the mixture, where a is the line width of the base layer 25 described in FIG. 2B, b is the linewidth of the molten Sn-58Bi, c is the width of the epoxy separated from the mixture, It means. In the present experimental example, the target pattern shape requires that the pattern of Sn-58Bi completely covers the upper portion of the lower layer, and that the line width is not too larger than the line width of the lower layer. In addition, in the case of epoxy, it is required to completely separate the Sn-58Bi pattern outwardly. Considering the risk of penetration into the device, it is necessary that the degree of spreading be uniformly maintained within 2 to 3 times the line width of the underlayer . In order to quantify these phase separation characteristics, phase separation (α) and spreading factor (β) were defined as follows.

Phase separation (?) = B / a

Spread (β) = c / a

FIG. 9B shows changes in phase separation () and degree of spread () depending on the epoxy content. In case of 0.2 wt%, the degree of spread was low as 2.0, but the phase separation was large as 1.5. In this case, phase separation did not occur effectively. It can be explained that the phase separation of Sn-58Bi and epoxy is not complete because of the insufficient flowability of epoxy due to the small amount of epoxy contained in the mixture. In the case of 0.5 wt%, the phase separation was about 1.2, so that most of Sn-58Bi and Cu, which is a sacrificial layer, migrated, and the epoxy moved out of the pattern. The spread also increased to 2.5. In the case of 1.0 wt%, the phase separation was not different from 0.5 wt%, but the spreading degree was greatly increased to 3.5. This means that the viscosity of the epoxy is too low, which means that the epoxy is pushed up to 3.5 times the design width of the multilayer thin film pattern at the time of printing or phase separation, which may affect the luminescent material inside the encapsulation line. As a result, it was judged that the phase separation property was the most excellent when the epoxy content was 0.5 wt%.

conclusion

Sn-58Bi and epoxy were mixed with each other using Joule heating, thereby developing a sealing method that does not deteriorate the organic light emitting diode device. As the sealing material, a mixture of Sn-58Bi, which is a low melting point alloy, and UV curable epoxy was printed. As the base layer, a multilayer thin film pattern of Mo (heat generating layer), SiO ₂ (insulating layer) And induced phase separation by Sn-Cu reaction. 5.8 W was applied to the heating layer of Mo for 60 seconds. As a result, the sealing pattern region was locally heated to melt the Sn-58Bi and obtain a double line structure by phase separation with epoxy. After that, the epoxy was cured by irradiating UV to secure the adhesive force of the sealing portion. Through the experiment, the thickness of the Cu thin film as the sacrificial layer was optimized to 3,000 Å, and the epoxy content was optimized to 0.5 wt%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10a, 10b: substrate
20: heat generating layer 22: insulating layer
24: sacrificial layer 25: ground layer
32, 32a: Low melting point alloy (layer)
34, 34a: Polymer organic material (layer)

Claims (8)

delete delete delete delete A first step of forming a heating layer which is a pattern locally disposed on a substrate;
A second step of forming a preliminary sealing material composed of a mixture of a low melting point alloy and a polymer organic substance on the heat generating layer; And
A low-melting-point alloy layer for protecting the organic light-emitting diode device mounted on the substrate from moisture and oxygen using the joule heat generated by applying a current to the heating layer, A polymeric organic material layer covering a void or a crack existing at an interface between the polymeric organic material layer and the polymeric organic material layer to form a double-sealed structure;
/ RTI >
The first step further comprises forming a sacrificial layer on the heating layer,
By the joule heat generated in the third step, at least some of the materials constituting the sacrificial layer react with at least a part of materials constituting the low melting point alloy layer to form a compound, whereby the low melting point alloy layer is selectively removed from the sacrificial layer With wetting,
A method for manufacturing an organic light emitting diode encapsulating structure. 6. The method of claim 5,
In the third step, the low melting point alloy layer is formed in contact with the sacrificial layer, and the polymer organic material layer is formed on both sides of the low melting point alloy layer. 6. The method of claim 5,
Wherein the first step further comprises forming an insulating layer interposed between the heating layer and the sacrificial layer. A first step of forming a heating layer which is a pattern locally disposed on a substrate;
A second step of forming a preliminary sealing material composed of a mixture of a low melting point alloy and a polymer organic substance on the heat generating layer;
A low-melting-point alloy layer for protecting the organic light-emitting diode device mounted on the substrate from moisture and oxygen using the joule heat generated by applying a current to the heating layer, A polymeric organic material layer covering a void or a crack existing at an interface between the polymeric organic material layer and the polymeric organic material layer to form a double-sealed structure; And
A fourth step of curing the polymer organic material layer after the third step;
Wherein the organic light-emitting diode encapsulation structure is formed on the substrate.

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