KR20180115134A - Micro light emitting diode module and its manufacturing method - Google Patents

Abstract

The present invention relates to a micro-LED module and a method for manufacturing the same, which can implement a display device or a lighting device using a micro-LED. The method of the present invention comprises: a first substrate preparation step of preparing a first substrate having a first electrode layer formed thereon; a first conductive paste forming step of forming a first conductive paste on the first electrode layer; a chip mounting step of mounting a first surface of a micro-LED chip on the first conductive paste; a second substrate preparation step of preparing a second substrate having a second electrode layer formed thereon; a second conductive paste forming step of forming a second conductive paste on a second surface or the second electrode layer of the micro-LED chip; and a second substrate mounting step of turning over the second substrate, and mounting the second conductive paste on the second surface of the micro-LED chip.

Description

Technical Field [0001] The present invention relates to a micro-LED module,

The present invention relates to a micro LED module and a method of manufacturing a micro LED module. More particularly, the present invention relates to a micro LED module and a method of manufacturing a micro LED module that enable a display device or a lighting device to be implemented using a micro LED.

Since the commercialization of nitride semiconductor light-emitting diodes (hereinafter referred to as GaN-LEDs), GaN-LED has achieved remarkable improvement in performance and reliability owing to the continuous development of semiconductor thin film technology, process technology and device technology. Demand for light emitting diodes (LEDs) has been explosively rising due to rapid growth and continuous introduction of high brightness and high power applications.

In addition, unlike conventional incandescent lamps and fluorescent lamps, GaN-LEDs have many advantages such as small size, low power consumption, high efficiency, and environmental friendliness. Recently, they have been applied to mid- And is expanding its scope not only to automotive lighting but also to general lighting market.

However, GaN-LEDs developed to date require further improvement in terms of luminous efficiency, light output and cost, and in particular, in order to expand applications of GaN-LEDs as general illumination, It is considered a top priority.

That is, the light generated inside the GaN-LED generates total internal reflection due to the difference in refractive index between the semiconductor and air, thereby increasing the light extraction efficiency. As a result, the problem is that the GaN- Has come.

In order to obtain a high light extraction efficiency, a method of manufacturing a high-brightness micro-array light-emitting diode device that minimizes photons that are trapped in the device or converted into heat by damaging total reflection geometrically is required.

Particularly, in the manufacturing process of the high-brightness microarray light-emitting diode device, the alignment process or the planarization process of the microarray pattern for depositing the transparent electrode on the upper surface of the microarray pattern requires highly precise and high-level work.

However, depending on the result of the alignment process or the planarization process for the placement of the micro LED chips on the substrate, the production cost may be greatly increased or the structure of the surface on which the transparent electrode is deposited may become complicated or uneven, There is a problem that the productivity of the product, the reproducibility of the process, and the reliability are inferior because it can be connected to a problem causing disconnection or short-circuit in the multilayer wiring process.

The idea of the present invention is to solve these problems by using a conductive paste to facilitate electrical or mechanical coupling between parts and to use a hydrophilic first side coated with a micro LED chip and a second hydrophobic side The present invention provides a micro LED module and a method of manufacturing a micro LED module that enable rapid chip alignment and planarization to improve the reliability of a product and significantly increase productivity by reducing production time and cost of a product. However, these problems are illustrative, and thus the scope of the present invention is not limited thereto.

According to an aspect of the present invention, there is provided a method of manufacturing a micro LED module, comprising: preparing a first substrate having a first electrode layer; A first conductive paste forming step of forming a first conductive paste on the first electrode layer; A chip mounting step of mounting a first surface of the micro LED chip on the first conductive paste; A second substrate preparation step of preparing a second substrate on which a second electrode layer is formed; A second conductive paste forming step of forming a second conductive paste on the second surface of the micro LED chip or the second electrode layer; And a second substrate mounting step of mounting the second conductive paste on the second surface of the micro LED chip by reversing the second substrate.

In the method of manufacturing a micro LED module according to the present invention, after the first substrate preparation step, a first partition wall layer having a first through hole exposing at least a part of the first electrode layer is formed on the first substrate A first barrier rib layer forming step of forming a first barrier rib layer.

Further, according to the present invention, the first conductive paste forming step may fill the first conductive paste in at least a part of the first through hole.

The micro-LED module manufacturing method according to the present invention may further include a paste curing step of curing the first conductive paste by heating or irradiating light after the first conductive paste forming step have.

According to the present invention, the chip mounting step may include: forming a hydrophilic surface or a hydrophobic surface on the first surface or the second surface of the wafer for micro LEDs or a plurality of the micro LED chips; Placing a plurality of the micro LED chips in a water tank so that the hydrophilic surface floats in the water direction or the hydrophobic surface floats so as to be natural aligned in the water surface direction; A chip adsorption step of adsorbing at least one micro LED chip naturally aligned using a vacuum hole formed on a vacuum adsorption plate with vacuum pressure; And releasing the vacuum pressure to place the micro LED chip adsorbed on the first conductive paste.

According to an aspect of the present invention, there is provided a micro LED module including: a first substrate; A first electrode layer formed on the first substrate; A first conductive paste formed on the first electrode layer; A micro LED chip on which a first surface is mounted on the first conductive paste; A second conductive paste formed on a second side of the micro LED chip; A second electrode layer formed on the second conductive paste; And a second substrate formed on the second electrode layer, wherein the first surface of the micro LED chip is hydrophilic and the second surface is hydrophobic.

Further, according to the present invention, the first conductive paste may be hydrophilic and the second conductive paste may be hydrophobic.

Also, according to the present invention, the first electrode layer may include a copper component, and the second electrode layer may be a transparent electrode.

According to another aspect of the present invention, there is provided a micro LED module, comprising: a first partition wall layer formed between the first substrate and the second substrate and having a first through hole for receiving the first conductive paste; And a second barrier rib layer formed between the first barrier rib layer and the second substrate and having a second through hole for receiving the second conductive paste.

According to some embodiments of the present invention as described above, a conductive paste is used to facilitate electrical or mechanical coupling between parts, and a hydrophilic first side coated with a micro LED chip and a second hydrophobic side It is possible to perform rapid chip alignment and planarization, thereby improving the reliability of the product, reducing the production time and cost of the product, thereby significantly increasing the productivity and producing a high quality product. Of course, the scope of the present invention is not limited by these effects.

1 is a cross-sectional view illustrating a micro LED module according to some embodiments of the present invention.
FIGS. 2 to 7 are cross-sectional views showing steps of manufacturing the micro-LED module of FIG.
8 is a flow chart illustrating a method of fabricating a micro LED module in accordance with some embodiments of the present invention.
9 is a flow chart illustrating a method of fabricating a micro LED module in accordance with some alternative embodiments of the present invention.
10 is a flowchart showing the chip mounting step of FIG. 8 in more detail.

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

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thickness and size of each layer are exaggerated for convenience and clarity of explanation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

Hereinafter, a micro LED module and a micro LED module manufacturing method according to some embodiments of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view illustrating a micro LED module 100 in accordance with some embodiments of the present invention.

1, a micro LED module 100 according to some embodiments of the present invention includes a first substrate 10, a first electrode layer 11, a first conductive paste (not shown) 12, a micro LED chip C, a second conductive paste 22, a second electrode layer 21, and a second substrate 20.

1, the first substrate 10 includes the first electrode layer 11, the first conductive paste 12, the micro LED chip C, the second conductive paste 12, Various types of substrates having sufficient strength and durability to support the conductive paste 22, the second electrode layer 21, and the second substrate 20 can be applied.

More specifically, various synthetic resin materials such as polyethylene terephthalate (PET), which is a soft material, may be applied to the first substrate 10 so as to implement a flexible display device using a micro LED.

However, the first substrate 10 is not necessarily limited to this, and may be a variety of substrate materials such as various printed circuit boards, metal substrates, ceramic substrates, glass substrates, synthetic resin substrates, and composite substrates All of which can be applied.

1, the first electrode layer 11 may include a high-conductivity copper component, an aluminum component, a gold component, a silver component, a platinum component, and the like. However, the present invention is not limited to this, and various conductive transparent electrode materials such as ITO (Indium Tin Oxide) can be applied. More specifically, the first electrode layer 11 may be patterned on the first substrate 10 using an etching process.

Also, for example, as shown in FIG. 1, the first conductive paste 12 may be a conductive bonding medium formed on the first electrode layer 11.

The first conductive paste 12 may serve to firmly bond the first electrode layer 11 and the micro LED chip to be described later electrically and mechanically to each other. For example, the first conductive paste 12 may include a graphene component, Component, a silver component, a tin component, a copper component, various metal components, and the like. Therefore, the position initially applied by self weight may not deviate greatly. The first conductive paste 12 may include a polymer mixture that can be volatilized or cured by heating or UV light irradiation, or a thermosetting or UV-curable medium such as ceramic or silicon or a volatile medium. have. The mixing ratio of the conductive powder and the curable medium may be determined according to the specifications of the first electrode layer 11, the processing environment, and the like. More specifically, for example, the first conductive paste 12 may be a paste containing graphene or a CNT component, or an epoxy solder paste in which an epoxy-based resin is mixed with a solder powder . However, the present invention is not limited thereto, and a wide variety of conductive pastes such as silver paste can be applied.

1, the micro-LED chip C is a package in which the first surface C-1 is mounted on the first conductive paste 12, The term, "micro" element, "micro" pn diode or "micro" LED structure may refer to a descriptive size of certain elements or structures in accordance with embodiments of the present invention. As used herein, the term "micro" element or structure is intended to refer to a scale of 1 to 100 μm. However, it should be appreciated that embodiments of the present invention are not necessarily so limited, and that certain embodiments of the embodiments may be applicable with larger and possibly smaller size scales.

For example, an embodiment of the present invention can describe a method of treating a bulk LED substrate with an array of micro-LED structures with preparation for transport to a pick-up and receiving substrate. In this way, it is possible to integrate and assemble the micro-LED structure in a heterogeneous integrated system. The micro LED structures can be picked up and transported individually, in groups, or as an entire array. Thus, a micro-LED structure in an array of micro-LED structures can be used as a receiving substrate, such as a display substrate of any size, from pick-up and micro-display to large-area display. More specifically, for example, the array of micro-LED structures can be described as having a pitch of 10 μm × 10 μm, or a pitch of 5 μm × 5 μm. At this density, a 15.2 cm (6 inch) substrate can be fabricated using, for example, approximately 165 million micro LED structures with a 10 μm × 10 μm pitch, or approximately 600 million with a 5 μm × 5 μm pitch It can accommodate 60 million micro LED structures. However, the micro LED module and micro LED module manufacturing method described herein are not limited to micro LED structures, and can also be used in the manufacture of other micro devices.

1, the second conductive paste 22 is formed on the second surface C-2 of the micro LED chip C, and the second electrode layer 21 is formed on the second surface C- The second substrate 20 may be formed on the second conductive layer 22 and the second substrate 20 may be formed on the second electrode layer 21.

The second conductive layer 22 may have the same structure and function as the first conductive paste 12 described above and the second electrode layer 21 may be formed on the first electrode layer 11, And the second substrate 20 may have the same configuration and function as the first substrate 10.

However, the second conductive paste 22 and the second electrode layer 21 may be formed of indium tin oxide (ITO) or the like so as to increase the transparency, in order that the light generated from the micro LED chips C may be emitted upward. The first conductive layer 12, the first electrode layer 11, and the first substrate 10 may be applied as a reflective material, for example, a transparent or translucent material such as an epoxy solder paste, . However, the present invention is not limited thereto, and various types of materials can be applied.

For example, the micro-LED chip C may be hydrophilic and the second surface C-2 may be hydrophobic, using the coating process or the self-nature.

It is also possible that the hydrophilic property of the first conductive paste 12 and that of the second conductive paste 22 on the first surface C-1 and the hydrophobic second surface C- The first conductive paste 12 may be hydrophilic and the second conductive paste 22 may be hydrophobic in order to further strengthen the mechanical adhesion to prevent shorts and to improve the reliability of the product.

More specifically, for example, the first surface (C-1) of the micro LED chip may be coated with a hydrophilic material to form a hydrophilic surface, and the second surface (C-2) The first conductive paste 12 may contain a hydrophilic material and the second conductive paste 22 may contain a hydrophobic material to form a hydrophobic surface .

1, a micro LED module 100 according to some embodiments of the present invention is formed between the first substrate 10 and the second substrate 20, and the first conductive A first partition wall layer W1 in which a first through hole H1 for accommodating the paste 12 is formed and a second partition wall layer W2 formed between the first partition wall layer W1 and the second substrate 20, And a second partition wall layer W2 in which a second through hole H2 for accommodating the conductive paste 22 is formed. The first barrier rib layer W1 and the second barrier rib layer W2 may be made of various synthetic resin materials such as polyethylene (PE), for example.

The first barrier rib layer W1 and the second barrier rib layer W2 may serve as a kind of spacer between the first substrate 10 and the second substrate 20, The first conductive layer 12 and the second conductive paste 22 may be guided to the first electrode layer 11 and the second electrode layer 21, respectively.

Therefore, the above-described conductive paste 12 (22) is used to facilitate the electrical or mechanical coupling between the components, and the hydrophilic first surface (C-1) coated on the micro LED chip (C) It is possible to perform rapid chip alignment and planarization by using the two sides (C-2), thereby improving the reliability of the product, reducing the production time and cost of the product, thereby greatly increasing the productivity and producing high quality products.

FIGS. 2 to 7 are cross-sectional views showing steps of manufacturing the micro-LED module 100 of FIG.

2 to 7, the manufacturing process of the micro LED module 100 of FIG. 1 will be described step by step. First, as shown in FIG. 2, a first substrate 11 having a first electrode layer 11 formed thereon, (10) can be prepared. At this time, a first barrier layer W1 having a first through hole H1 exposing at least a part of the first electrode layer 11 may be formed on the first substrate 10. [

Then, as shown in FIG. 3, a first conductive paste 12 may be formed on the first electrode layer 11. At this time, the first conductive paste 12 is filled on the first electrode layer 11 in the first through hole H1 using various coating processes such as dispensing, dotting, inkjet printing, screen printing, .

4, in order to mount the first surface C-1 of the micro LED chip C on the first conductive paste 12, first, a wafer for a micro LED or a plurality of A hydrophilic surface or a hydrophobic surface is formed on the first surface (C-1) or the second surface (C-2) of the micro LED chips (C), and a plurality of micro LED chips (C) The hydrophilic surface can be floated so that it is naturally aligned in the water direction or the hydrophobic surface is naturally aligned in the water surface direction.

Next, as shown in FIG. 5, at least one micro-LED chip C naturally aligned as shown in FIG. 4 can be vacuum-suctioned by using the vacuum hole H3 formed in the vacuum adsorption plate 30 .

At this time, hydrophobic or hydrophilic coating may be applied to the surface of the vacuum adsorption plate 30 or the inside of the vacuum hole H3 while using the vacuum pressure, thereby facilitating the transfer of the micro LED chips C.

6, the internal vacuum pressure of the vacuum hole H3 of the vacuum adsorption plate 30 is released or a positive pressure is generated, and the adsorbed micro-LED chip C is transferred to the first conductive paste (12).

7, the second substrate 20 on which the second electrode layer 21 is formed is prepared and the second surface C-2 of the micro LED chip C or the second electrode layer And the second conductive paste 22 of the second substrate 20 is formed by inverting the second substrate 20 to form the micro LED chip 20 C on the second surface C-2. Here, the process of forming the second substrate 20, the second electrode layer 21, and the second conductive paste 22 is the same as that of the first substrate 10 illustrated in FIGS. 2 to 10, May be the same as the formation process of the first electrode layer 11 and the first conductive paste 12.

Next, though not shown, the first conductive paste 12 and the second conductive paste 22 are heated or irradiated with light such as UV light to form the first conductive paste 12 and the second conductive paste 22, The conductive paste 22 can be cured.

8 is a flow chart illustrating a method of fabricating a micro LED module in accordance with some embodiments of the present invention.

1 to 8, a method of fabricating a micro LED module according to some embodiments of the present invention includes a first substrate preparation step of preparing a first substrate 10 on which a first electrode layer 11 is formed A first conductive paste forming step S2 for forming a first conductive paste 12 on the first electrode layer 11 and a second conductive paste forming step S2 for forming a first conductive paste 12 on the first conductive paste 12, A chip mounting step S3 for mounting the first surface C-1 of the first electrode layer C on the first substrate 2, a second substrate preparing step S4 for preparing the second substrate 20 on which the second electrode layer 21 is formed, A second conductive paste forming step (S5) of forming a second conductive paste (22) on the second surface (C-2) of the micro LED chip (C) or the second electrode layer (21) (C-2) of the micro-LED chip (C), and a second conductive paste (22) of the second substrate (20) ) The substrate may include a second mounting step (S7).

9 is a flow chart illustrating a method of fabricating a micro LED module in accordance with some alternative embodiments of the present invention.

1 to 9, a method of manufacturing a micro LED module according to some other embodiments of the present invention includes a step of preparing a first substrate 10, (S8) forming a first barrier rib layer (W1) having a first through hole (H1) for exposing at least a part of the first electrode layer (11) on the first substrate layer Forming a second barrier layer W2 having a second through hole H2 exposing at least a portion of the second electrode layer 21 on the second substrate 20 after step S4, (S10) for hardening the first conductive paste 12 by heating or irradiating light after the step of forming the partition wall layer (S9) and the step of forming the first conductive paste .

Fig. 10 is a flowchart showing the chip mounting step S3 of Fig. 8 in more detail.

As shown in FIGS. 4 to 10, the chip mounting step S3 includes a step of mounting the micro LED chip or the plurality of micro LED chips C on the first surface C-1 or the second surface C- A hydrophilic surface forming step S31 for forming a hydrophilic surface or a hydrophobic surface on the hydrophilic surface 2 in the water tank 1 and a plurality of micro LED chips C are put into the water tank 1 as shown in FIG. As shown in FIG. 5, and a vacuum hole H3 formed in the vacuum adsorption plate 30, as shown in FIG. 5, to float the hydrophobic surface or the hydrophobic surface so that the hydrophobic surface is naturally aligned in the water surface direction, 6, the micro-LED chip C is attracted to the first conductive paste 12 (FIG. 6) by releasing the vacuum pressure, (Step S34). .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: first substrate
11: First electrode layer
12: first conductive paste
C: Micro LED chip
C-1: First side
C-2: Second side
20: second substrate
21: Second electrode layer
22: second conductive paste
W1: first partition wall layer
W2: second partition wall layer
H1: First through hole
H2: Second through hole
1: aquarium
30: Vacuum suction plate
H3: Vacuum hole
100: Micro LED module

Claims (9)

A first substrate preparation step of preparing a first substrate on which a first electrode layer is formed;
A first conductive paste forming step of forming a first conductive paste on the first electrode layer;
A chip mounting step of mounting a first surface of the micro LED chip on the first conductive paste;
A second substrate preparation step of preparing a second substrate on which a second electrode layer is formed;
A second conductive paste forming step of forming a second conductive paste on the second surface of the micro LED chip or the second electrode layer; And
A second substrate mounting step of mounting the second conductive paste on the second surface of the micro LED chip by reversing the second substrate;
≪ / RTI > The method according to claim 1,
After the first substrate preparation step,
A first barrier rib layer forming step of forming a first barrier rib layer having a first through hole exposing at least a part of the first electrode layer on the first substrate;
≪ / RTI > 3. The method of claim 2,
Wherein the forming of the first conductive paste comprises filling the first conductive paste in at least a portion of the first through hole. The method according to claim 1,
A paste curing step of curing the first conductive paste by heating or irradiating light after the first conductive paste forming step;
≪ / RTI > The method according to claim 1,
Wherein the chip mounting step includes:
Forming a hydrophilic surface or a hydrophobic surface on the first surface or the second surface of the wafer for micro LEDs or a plurality of the micro LED chips;
Placing a plurality of the micro LED chips in a water tank so that the hydrophilic surface floats in the water direction or the hydrophobic surface floats so as to be natural aligned in the water surface direction;
A chip adsorption step of adsorbing at least one micro LED chip naturally aligned using a vacuum hole formed on a vacuum adsorption plate with vacuum pressure; And
Releasing vacuum pressure to place the micro-LED chip adsorbed on the first conductive paste;
≪ / RTI > A first substrate;
A first electrode layer formed on the first substrate;
A first conductive paste formed on the first electrode layer;
A micro LED chip on which a first surface is mounted on the first conductive paste;
A second conductive paste formed on a second side of the micro LED chip;
A second electrode layer formed on the second conductive paste; And
And a second substrate formed on the second electrode layer,
Wherein the first side of the micro LED chip is hydrophilic and the second side is hydrophobic. The method according to claim 6,
Wherein the first conductive paste is hydrophilic and the second conductive paste is hydrophobic. The method according to claim 6,
Wherein the first electrode layer comprises a copper component and the second electrode layer is a transparent electrode. The method according to claim 6,
A first partition wall layer formed between the first substrate and the second substrate and having a first through hole for receiving the first conductive paste; And
A second partition wall layer formed between the first partition wall layer and the second substrate and having a second through hole for receiving the second conductive paste;
Further comprising a micro-LED module.

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