CN111373553A - A light-emitting device, preparation method thereof, and display device - Google Patents

Abstract

The invention discloses a light-emitting device, a preparation method thereof, and a display device. The light-emitting device comprises: an electrode, a solder layer arranged on the electrode, an anti-oxidation layer arranged on the solder layer, and an anti-oxidation layer arranged on the solder layer. The light-emitting element on the anti-oxidation layer; the solder layer can be thermally expanded and connected to the light-emitting element located above the solder layer; the anti-oxidation layer is used to protect the solder layer from oxidation. An anti-oxidation layer is provided on the solder layer, so that the solder will not be oxidized during heat treatment, and the solder layer will expand and connect to the light-emitting element. That is, the process of applying pressure in the prior art is omitted, thereby avoiding the problem of damage to the light-emitting element caused by the application of pressure.

Description

A light-emitting device, preparation method thereof, and display device

technical field

The present invention relates to the technical field of light-emitting devices, in particular to a light-emitting device, a preparation method thereof, and a display device.

Background technique

In the prior art, as shown in FIG. 1 , during the preparation of Micro-LED, millions of micro-LED chips of micron level are transferred to the substrate at the same time, so that the metal electrodes of the chip 3 and the metal circuit 1 of the backplane are connected to each other. The solder 2 is in contact with each other. After accurate alignment, heat treatment is applied, and appropriate pressure is applied to connect the metal electrode of the chip 3 to the metal circuit 1 of the backplane through the solder 2. If the pressure is slightly too large, it will cause the chip 3 If the structure is damaged, the damaged chip 3 cannot be lit.

Therefore, the existing technology still needs to be improved and developed.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a light-emitting device, a preparation method thereof, and a display device in view of the above-mentioned defects of the prior art, aiming to solve the problem of damage to the chip structure caused by pressure application in the prior art.

The technical scheme adopted by the present invention to solve the technical problem is as follows:

A light-emitting device, comprising: an electrode, a solder layer arranged on the electrode, an anti-oxidation layer arranged on the solder layer, and a light-emitting element arranged on the oxidation-resistant layer; the solder layer can be After thermal expansion, it is connected to the light-emitting element located above the solder layer; the anti-oxidation layer is used to protect the solder layer from oxidation.

In the light-emitting device, a solder groove is provided on the electrode, the solder layer is located in the solder groove, and the anti-oxidation layer is lower than the opening of the solder groove.

In the light-emitting device, a UBM layer is disposed on the electrode, the solder layer is located in the groove of the UBM layer, and the anti-oxidation layer is lower than the opening of the groove.

In the light-emitting device, the solder layer is one or more of an indium solder layer and a tin solder layer.

In the light-emitting device, the anti-oxidation layer is one or more of a silver layer, a molybdenum layer, a platinum layer, a gold layer, a palladium layer, a ruthenium layer, a rhodium layer, and an iridium layer.

In the light-emitting device, the thickness of the anti-oxidation layer is 20-200 nm.

A display device, comprising the light-emitting device according to any one of the above.

A preparation method of a light-emitting device, comprising the following steps:

providing an electrode on which a solder layer is dotted;

plating an anti-oxidation layer on the solder layer;

placing a light-emitting element over and aligned with the solder layer;

The heat treatment of the solder layer expands the solder layer and connects with the light-emitting element.

The preparation method of the light-emitting device, wherein the providing an electrode, and the spot solder layer on the electrode comprises:

An electrode is provided; wherein, a solder groove is provided on the electrode;

A solder layer is spotted in the solder bath.

The preparation method of the light-emitting device, wherein the providing an electrode, and the spot solder layer on the electrode comprises:

providing an electrode on which a UBM layer is disposed;

A solder layer is dotted within the grooves of the UBM layer.

Beneficial effects: an anti-oxidation layer is arranged on the solder layer, the solder will not be oxidized during heating treatment, and the solder layer will expand and be connected with the light-emitting element. That is, the process of applying pressure in the prior art is omitted, thereby avoiding the problem of damage to the light-emitting element due to the application of pressure.

Description of drawings

FIG. 1 is a schematic diagram of the preparation process of Micro-LED in the prior art.

FIG. 2 is a flow chart of the preparation of the light-emitting device in the present invention.

FIG. 3 is a schematic structural diagram of electrodes, solder layers and oxide layers in the present invention.

FIG. 4 is a schematic structural diagram of electrodes, solder layers, oxide layers, and Micro-LEDs in the present invention.

FIG. 5 is a schematic structural diagram of a light-emitting element in the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Please refer to FIGS. 3-5 at the same time, the present invention provides some embodiments of a light-emitting device.

As shown in FIG. 5 , a light-emitting device of the present invention includes: an electrode 10, a solder layer 20 arranged on the electrode 10, an anti-oxidation layer 30 arranged on the solder layer 20, and an anti-oxidation layer 30 arranged on the solder layer 20. The light-emitting element on the oxide layer 30; the solder layer 20 can be thermally expanded and connected to the light-emitting element located above the solder layer 20; the anti-oxidation layer 30 is used to protect the solder layer 20 from oxidation.

The light-emitting device in the present invention is prepared by the following steps:

S100 , an electrode 10 is provided, and a solder layer 20 is dotted on the electrode 10 .

S200 , plating an anti-oxidation layer 30 on the solder layer 20 .

S300 , placing the light-emitting element above the solder layer 20 and aligning it with the solder layer 20 .

S400 , heating the solder layer 20 to expand the solder layer 20 and connect it with the light emitting element.

It is worth noting that, if the anti-oxidation layer 30 is arranged on the solder layer 20, the solder will not be oxidized during the heat treatment (if the anti-oxidation layer 30 is not arranged, the solder will be oxidized, and will not expand, and will not connecting the light-emitting element), the solder layer 20 expands and connects with the light-emitting element. That is, the process of applying pressure in the prior art is omitted, thereby avoiding the problem of damage to the light-emitting element caused by applying pressure, thereby improving the yield.

In a preferred embodiment of the present invention, as shown in FIG. 3 to FIG. 4 , the electrode 10 is provided with a solder groove, the solder layer 20 is located in the solder groove, and the anti-oxidation layer 30 is lower than the opening of the solder groove.

Specifically, in order to prevent the expansion of the solder in the horizontal plane during the heat treatment expansion, a solder groove is provided on the electrode 10, the solder layer 20 is arranged in the solder groove, and the height of the solder groove is set as required, so that there will be no solder overflow. problem so that there is enough solder to connect with the light-emitting element.

The electrode 10 is provided with a UBM (Under bump Metallurgy, under bump metal structure) layer 11 , the solder layer 20 is located in the groove 12 of the UBM layer 11 ; the anti-oxidation layer 30 is lower than the concave The opening of the slot 12. Since the UBM layer 11 has grooves 12 , the problem of solder overflow can also be prevented, and the UBM layer 11 can increase the adhesion between the solder and the electrode 10 to prevent the solder layer 20 from falling off the electrode 10 . If the grooves 12 of the UBM layer 11 are not deep enough, the grooves 12 can be raised to prevent the solder from overflowing.

The shapes of the solder grooves and grooves 12 can be set as required, for example, set in a rectangular, circular and other shapes. It can be set according to the shape of the light-emitting element, so that the solder takes on the shape of the light-emitting element, so that the light-emitting element can be sufficiently adhered.

The number of solder grooves and grooves 12 can be set as required, for example, each light-emitting element corresponds to several solder grooves or grooves 12, which can reduce the possibility of the solder layer 20 being oxidized, and even if a small amount of the solder layer 20 appears If the overflow occurs, it will overflow to the position between two adjacent solder grooves (or grooves 12 ), thereby increasing the contact area between the solder layer 20 and the light-emitting element. The solder grooves or grooves 12 can be arranged in a matrix arrangement, or arranged according to the shape of the light emitting element. Of course, according to requirements, in order to reduce the amount of solder, solder grooves or grooves 12 in a specific arrangement can be used, for example, in a rectangular distribution, and the solder grooves or grooves 12 are distributed on each side of the rectangle.

In a preferred embodiment of the present invention, the solder layer 20 is one or more of an indium (In) solder layer and a tin (Sn) solder layer. Specifically, other solders can also be used to form the solder layer 20. Of course, the solder layer 20 needs to have better expansion performance during heat treatment (the temperature of the heat treatment is 100-300°C). When a variety of solders are used in combination, the composition of the solder with high thermal expansion coefficient can be increased. For example, when indium-tin solder is used, the content of indium can be increased and the content of tin can be reduced, thereby increasing the expansion coefficient of the solder. The content of each component is comprehensively considered to ensure expansion performance and adhesion performance, that is, to ensure that the expansion is high enough to adhere to the light-emitting element, and that the adhesion is stable enough to not cause the light-emitting element to loosen or fall off.

When using solder with multiple components, the solder layer 20 includes: several sub-solder layers arranged in sequence in the vertical direction. The expansion coefficient of each sub-solder layer increases sequentially from top to bottom. Each sub-solder layer is formed by arranging each solder in layers, for example, each sub-solder is sequentially dotted in the solder groove or groove 12 . The solder with a small expansion coefficient is arranged above, so as to avoid affecting the adhesion performance between the light-emitting element and the solder layer 20 when the solder cools down and shrinks. It should be noted that, after the light-emitting element and the solder layer 20 are adhered, even if the temperature drops, the solder layer 20 will be oxidized to a certain extent, but will not shrink to a large extent. However, since the solder in the solder groove and groove 12 (or the lower layer) is less accessible to oxygen and oxidized than the expanded (or upper layer) solder, it shrinks to a higher degree during cooling.

The depths of the solder grooves and grooves 12 need to be determined according to the expansion coefficient of the solder layer 20 and the temperature of the heating process. During the heating process, the solder layer 20 will not overflow into the solder grooves or grooves 12 due to excessive expansion. The solder grooves and grooves 12 cannot be set too high, which increases the difficulty of expansion of the solder layer 20 and prevents the problem that the solder layer 20 cannot be adhered to the light-emitting element.

In a preferred embodiment of the present invention, the anti-oxidation layer 30 is one or more of a silver layer, a molybdenum layer, a platinum layer, a gold layer, a palladium layer, a ruthenium layer, a rhodium layer, and an iridium layer. Specifically, the anti-oxidation layer 30 is deposited on the solder layer 20 by evaporation (including physical evaporation and chemical evaporation) or sputtering. Of course, other anti-oxidation materials can also be used to make the anti-oxidation layer 30, such as A material that does not react with oxygen in the air during heat treatment. The thickness of the anti-oxidation layer 30 is 20-200 nm. The thickness of the anti-oxidation layer 30 can be set according to the actual situation, and is not limited to the range of 20-200 nm. The thickness of the anti-oxidation layer 30 should not be too thick. Connection of the light-emitting element; the thickness of the anti-oxidation layer 30 should not be too thin, because if it is too thin, the anti-oxidation effect cannot be achieved. After the solder is oxidized, it cannot expand, and the connection with the light-emitting element cannot be realized.

In a preferred embodiment of the present invention, as shown in FIGS. 4-5 , the light-emitting element is a Micro-LED 40 . The Micro-LED 40 includes: a pad point 41 connected to the anti-oxidation layer 30 , and an LED chip 42 connected to the pad point 41 .

Specifically, when the solder layer 20 expands, the solder in the solder layer 20 breaks through the anti-oxidation layer 30 so as to be welded with the pad point 41 to realize the connection between the light-emitting element and the electrode 10 .

Based on the above-mentioned light-emitting device, the present invention also provides a preferred embodiment of a display device:

A display device according to an embodiment of the present invention includes the light-emitting device according to any one of the above embodiments.

Based on the above light-emitting device, the present invention also provides a preferred embodiment of a method for preparing a light-emitting device:

As shown in FIG. 2, the preparation method of the light-emitting device according to the embodiment of the present invention includes the following steps:

In step S100 , an electrode 10 is provided, and the solder layer 20 is dotted on the electrode 10 .

Specifically, the solder layer 20 in the present invention is one or more of an indium solder layer and a tin solder layer, as described above.

Specifically, there are two implementations of step S100. In the first implementation, step S100 includes:

In step S110a, an electrode 10 is provided; wherein, the electrode 10 is provided with a solder groove.

Step S120a, spot the solder layer 20 in the solder groove.

The solder bath can avoid the problem of overflow of the solder in the solder layer 20 during heating, as described above.

In the second embodiment, step S100 includes:

In step S110b, an electrode 10 is provided, and a UBM layer is arranged on the electrode 10.

It should be pointed out that the UBM layer 11 can be provided on the basis of the solder groove in the first embodiment, to further improve the adhesion between the solder layer 20 and the electrode 10 .

Step S120b , spot the solder layer 20 in the groove 12 of the UBM layer 11 .

The UBM layer 11 has a groove 12, and the solder layer 20 is located in the groove 12, which can also prevent the solder in the solder layer 20 from overflowing during heating.

Specifically, the solder grooves and UBM layer 11 are provided to obtain a predetermined shape, number and depth of the solder grooves and grooves 12 . Depending on the shape, number and depth of the solder grooves or recesses 12, the solder layer 20 is applied. When the solder layer 20 is spotted, the composition and amount of the solder layer 20 are determined. For example, when the solder layer 20 adopts several sub-solder layers, each sub-solder layer is sequentially dotted in the solder groove or groove 12 to obtain a sub-solder layer, thereby forming the solder layer 20 . When spotting each sub-solder, the sub-solder layer with the larger point expansion coefficient is first, and then the sub-solder layer with the smaller point expansion coefficient is placed.

Step S200 , plating an anti-oxidation layer 30 on the solder layer 20 .

In the present invention, the first one or more of silver layer, molybdenum layer, platinum layer, gold layer, palladium layer, ruthenium layer, rhodium layer and iridium layer are used as anti-oxidation layer 30, and evaporation (including physical evaporation and chemical evaporation) is adopted. It is deposited on the solder layer 20 by means of vapor deposition) or sputtering. Of course, other anti-oxidation materials can also be used to form the anti-oxidation layer 30 .

Step S300 , placing the light-emitting element on the solder layer 20 and aligning with the solder layer 20 .

Specifically, when the light-emitting element is located above the solder layer 20, there may be a gap between the light-emitting element and the solder layer 20. For example, the space between the light-emitting element and the solder layer 20 is determined according to the degree of expansion of the solder layer 20, or the height of the expansion. When one light-emitting element corresponds to multiple solder grooves or grooves 12, the light-emitting element can be directly placed on the solder grooves or grooves 12, and the plane between two adjacent solder grooves (or grooves 12) can be To support the light-emitting element, when the solder layer 20 expands, the solder can overflow onto the plane between two adjacent solder grooves (or grooves 12 ) so as to adhere to the light-emitting element. There may be no gap between the light-emitting element and the solder layer 20 , that is, the light-emitting element is in contact with the solder layer 20 . Of course, the light-emitting element and the solder layer 20 are aligned at this time.

The light-emitting element in the present invention adopts Micro-LED. When a Micro-LED with a smaller size is used, the Micro-LED is transferred to the top of the solder layer 20 by means of mass transfer.

Step S400 , heating the solder layer 20 to expand the solder layer 20 and connect it with the light-emitting element.

Specifically, the solder layer 20 can be heated from the back surface of the electrode 10 (the side on which the solder layer 20 is not provided) to expand the solder layer 20 to realize connection with the light-emitting element.

Specifically, the temperature of the heat treatment is determined according to the depth of the groove 12 or the solder groove, and the expansion coefficient of the solder layer 20 . That is, the solder layer 20 can expand and contact the light-emitting element and adhere to the light-emitting element. Of course, the solder layer 20 cannot be over-expanded, so that the solder overflows too much and causes a short circuit.

To sum up, the present invention provides a light-emitting device, a preparation method thereof, and a display device, wherein the light-emitting device comprises: an electrode, a solder layer arranged on the electrode, and an anti-oxidation device arranged on the solder layer. The anti-oxidation layer is used to protect the solder layer from oxidation. An anti-oxidation layer is provided on the solder layer, so that the solder will not be oxidized during heat treatment, and the solder layer will expand and connect to the light-emitting element. That is, the process of applying pressure in the prior art is omitted, thereby avoiding the problem of damage to the light-emitting element due to the application of pressure.

It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. A light emitting device, comprising: an electrode, a solder layer disposed on the electrode, an oxidation resistant layer disposed on the solder layer, a light emitting element disposed on the oxidation resistant layer; the solder layer can be connected with the light-emitting element positioned above the solder layer after being heated and expanded; the anti-oxidation layer is used for protecting the solder layer from oxidation.

2. The light-emitting device according to claim 1, wherein a solder groove is provided on the electrode, the solder layer is located in the solder groove, and the oxidation resistant layer is lower than an opening of the solder groove.

3. The light emitting device of claim 1, wherein the electrode has a UBM layer disposed thereon, the solder layer being located in a recess of the UBM layer; the anti-oxidation layer is lower than the opening of the groove.

4. The light emitting device of claim 1, wherein the solder layer is one or more of an indium solder layer and a tin solder layer.

5. The light emitting device of claim 1, wherein the oxidation resistant layer is a first or more of a layer of silver, a layer of molybdenum, a layer of platinum, a layer of gold, a layer of palladium, a layer of ruthenium, a layer of rhodium, a layer of iridium.

6. The light-emitting device according to claim 1, wherein the thickness of the oxidation resistant layer is 20 to 200 nm.

7. A display device comprising the light-emitting device according to any one of claims 1 to 7.

8. A method for manufacturing a light emitting device, comprising the steps of:

providing an electrode, and dotting a solder layer on the electrode;

plating an anti-oxidation layer on the solder layer;

placing a light emitting element over and in alignment with the solder layer;

and heating the solder layer to expand the solder layer and connect the solder layer with the light-emitting element.

9. The method of claim 8, wherein said providing an electrode on which a solder layer is dotted comprises:

providing an electrode; wherein, a solder groove is arranged on the electrode;

and dotting a solder layer in the solder groove.

10. The method of claim 8, wherein said providing an electrode on which a solder layer is dotted comprises:

providing an electrode, and arranging a UBM layer on the electrode;

and dotting a solder layer in the groove of the UBM layer.

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