CN210296404U

CN210296404U - LED chip structure

Info

Publication number: CN210296404U
Application number: CN201921568207.3U
Authority: CN
Inventors: 李成明; 许水珍; 倪绿军; 陈建; 杨功寿; 王�琦; 张国义
Original assignee: Dongguan Institute of Opto Electronics Peking University
Current assignee: Dongguan Institute of Opto Electronics Peking University
Priority date: 2019-09-19
Filing date: 2019-09-19
Publication date: 2020-04-10
Anticipated expiration: 2029-09-19

Abstract

The utility model relates to the field of semiconductor technology, concretely relates to LED chip structure, the utility model discloses a LED chip structure includes substrate and luminescence unit, and luminescence unit is connected with the substrate, still includes passivation layer and ohmic contact layer, and luminescence unit is equipped with the metal level with the substrate junction, and the passivation layer encloses to be located luminescence unit around, and passivation layer and metal level connection, and ohmic contact layer locates the passivation layer, and ohmic contact layer is connected with luminescence unit, the utility model provides a LED chip structure, reasonable in design, in the huge transfer process, need not to discern the electrode of LED chip, reduce the counterpoint degree of difficulty, the convenient transfer.

Description

LED chip structure

Technical Field

The utility model relates to the field of semiconductor technology, especially, relate to a LED chip structure.

Background

Light Emitting Diodes (LEDs) are widely used in the technical fields of illumination and display due to their advantages of small size, low power, long service life, high brightness, and active Light emission. Micro LEDs, also known as micro LEDs, mleds or muleds, are a new type of flat panel display technology, and have an LED array of individual pixel elements, which provides better contrast, faster response speed, and lower power consumption than currently widely used liquid crystal displays.

Since the micro LED is separately manufactured in the form of a chip, a huge amount of micro LED chips need to be transferred onto a substrate in the process of manufacturing a display device. At present, the huge transfer mode of the micro LED chip mainly comprises single picking, placing and transferring, fluid assembling, liquid surface self-assembling, electrostatic self-assembling, laser transferring, roller transferring and the like.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem, the utility model provides a LED chip structure, reasonable in design conveniently shifts.

The utility model adopts the technical proposal that: the LED chip structure comprises a substrate and a light emitting unit, wherein the light emitting unit is connected with the substrate, the LED chip structure further comprises a passivation layer and an ohmic contact layer, a metal layer is arranged at the joint of the light emitting unit and the substrate, the passivation layer surrounds the periphery of the light emitting unit and is connected with the metal layer, and the ohmic contact layer is arranged on the passivation layer and is connected with the light emitting unit.

The technical scheme is further improved in that the light-emitting unit comprises an LED epitaxial layer, a bonding layer and a buffer layer which are sequentially arranged, and the LED epitaxial layer is connected with the metal layer.

A further improvement of the above solution is that the substrate is made of an etchable material.

A further improvement to the above solution is that the substrate is made of silicon.

The further improvement of the technical scheme is that the bonding layer is made of NiAu, and an Au layer is arranged on the outermost layer of the bonding layer.

The utility model has the advantages as follows:

the utility model discloses a LED chip structure includes substrate and luminescence unit, and luminescence unit is connected with the substrate, still includes passivation layer and ohmic contact layer, and luminescence unit is equipped with the metal level with the substrate junction, and the passivation layer encloses to be located luminescence unit all around, and passivation layer and metal level connection, and ohmic contact layer is located the passivation layer, and ohmic contact layer is connected with luminescence unit, the utility model provides a LED chip structure, reasonable in design, ohmic contact layer is located the outside, need not to discern the electrode of LED chip in the huge transfer process, can reduce the counterpoint degree of difficulty, the convenient transfer.

Drawings

Fig. 1 is a schematic structural view of an LED chip of the present invention;

fig. 2 is a schematic view of the epitaxial structure of the present invention;

fig. 3 is a schematic structural view of the epitaxial material of the present invention;

fig. 4 is a schematic structural view of the bonding material of the present invention;

FIG. 5 is a schematic view of the structure of FIG. 4 with the sapphire substrate removed;

FIG. 6 is a schematic view of the template of FIG. 5 after implantation;

FIG. 7 is a schematic view of the structure of FIG. 6 after removal of the target substrate;

FIG. 8 is a schematic view of the structure of FIG. 7 after transfer to a target substrate;

FIG. 9 is a schematic view of the structure of FIG. 8 with the template removed;

FIG. 10 is a schematic view of the structure of FIG. 9 with the wax layer removed;

description of reference numerals: 1. the LED light source comprises a target substrate, 2 light emitting units, 3 LED epitaxial layers, 4 bonding layers, 5 metal layers, 6 passivation layers, 7 ohmic contact layers, 8 epitaxial structures, 9 templates, 10 target substrates, 11 wax layers, 12 limiting structures, 13 sapphire substrates and 14 buffer layers.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1-10, the LED chip structure of this embodiment, including substrate and luminescence unit 2, luminescence unit 2 is connected with the substrate, still includes passivation layer 6 and ohmic contact layer 7, and luminescence unit 2 is equipped with metal level 5 with the substrate junction, and passivation layer 6 encloses to be located luminescence unit 2 around, and passivation layer 6 is connected with metal level 5, and ohmic contact layer 7 wraps and locates passivation layer 6, and ohmic contact layer 7 is connected with luminescence unit 2, the utility model provides a LED chip structure, reasonable in design, ohmic contact layer 7 wraps and locates the outside, need not to discern the electrode of LED chip in the huge transfer process, can reduce the counterpoint degree of difficulty, the convenient transfer.

Luminous element 2 is connected with metal level 5 including the LED epitaxial layer 3, bonding layer 4 and the buffer layer 14 that set gradually, LED epitaxial layer 3, specifically, the utility model discloses a buffer layer 14 is gallium nitride buffer layer 14 and participates in miscellaneous layer, the utility model discloses such setting, the circuit switch-on of luminous element 2 and outside base plate of being convenient for, simultaneously the utility model discloses a setting of buffer layer 14 can make that crystal structure is the same or close, the lattice constant mismatch degree is little, crystallization performance is good, defect density is little.

The substrate is made of an etchable material, and the arrangement is mainly convenient for etching processing in the chip preparation process and reduces the processing and preparation difficulty.

Bonding layer 4 is made by NiAu, and such setting is mainly for better bonding, has great lattice mismatch and thermal expansion mismatch when effectively avoiding GaN and Si direct bonding for GaN is difficult to the direct bonding in Si material, and bonding layer 4 is outmost to be equipped with the Au layer, and the setting on Au layer, mainly used LED chip are electrically conductive, and electrically conductive effectual, convenient to use.

The preparation method of the LED chip structure comprises the following steps:

the method comprises the following steps: preparing an epitaxial structure 8;

step two: arranging a bonding layer 4 on the epitaxial structure 8 to prepare an epitaxial material with the bonding layer 4;

step three: transferring the epitaxial material in the second step to a target substrate 1, and bonding the epitaxial material and the target substrate 1 to form a bonding material;

step four: and etching the bonding material in the third step, and etching the bonding material from the side provided with the bonding layer 4 to the substrate to form the LED chip structure.

The epitaxial structure 8 comprises a sapphire substrate 13, a buffer layer 14 and an LED epitaxial layer 3 which are arranged in sequence.

After the epitaxial material and the target substrate 1 are bonded in step three, the sapphire substrate 13 is removed.

The preparation method provided by the invention is simple in process, the LED chip is processed by the processes of material bonding, etching and the like, the preparation is convenient, and the prepared LED chip is compact and reasonable in structure and good in use effect.

The method comprises implanting the LED chip structure into a template 9, removing the substrate by etching with acidic solution, such as hydrochloric acid solution, transferring the LED chip to a target substrate 10, solidifying, arranging a wax layer 11 on the template 9 close to the LED chip structure, arranging a limit structure 12 on the target substrate 10 for limiting the position of the LED chip structure, immersing the LED chip implanted in the template 9 in liquid, placing the target substrate 10 in the liquid, pushing the target substrate 10 to the lower part of the LED chip by the buoyancy of the liquid, inserting the LED chip into the limit structure 12 of the target substrate 10, positioning by the conventional positioning method in the photoetching, secondary photoetching or overlay process, increasing the accuracy of transfer, removing the target substrate 10 with the LED chip out of the liquid level, at the moment, a part of the wax layer 11 is melted by micro-heating, the template 9 is removed, then the LED chip and the target substrate 10 are subjected to die bonding, after die bonding, the wax layer 11 is completely melted, after the wax layer 11 is removed, huge transfer of the LED chip structure is completed, liquid for providing buoyancy for the target substrate 10 and the LED chip is organic solvent with small density, such as ethanol, acetone and the like, inorganic solvent, such as water, is selected, only after the huge transfer is completed, a drying step is required, such as the selection of the organic solvent, the liquid on the surface of the chip is volatilized, and drying is not required, the huge transfer method of the LED chip is to carry out the huge transfer of the LED chip by an etching process, in the huge transfer process of the LED chip, the position of the LED chip is limited firstly by arranging the template 9, but the wax layer 11 is preset at the connection position of the template 9 and the LED chip, and the wax layer 11 can be heated and melted very easily after the huge transfer is completed, when the wax layer 11 is partially melted, the template 9 is loosened and can be directly removed, after subsequent processing is finished, the wax layer 11 can be completely melted and removed, but in the processing process, the wax layer 11 does not need to be completely removed, and the wax layer 11 can play a role in protecting the LED chips.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. The LED chip structure comprises a substrate and a light emitting unit, wherein the light emitting unit is connected with the substrate, and the LED chip structure is characterized by further comprising a passivation layer and an ohmic contact layer, a metal layer is arranged at the joint of the light emitting unit and the substrate, the passivation layer is arranged around the light emitting unit and is connected with the metal layer, and the ohmic contact layer is arranged on the passivation layer and is connected with the light emitting unit.

2. The LED chip structure of claim 1, wherein the light-emitting unit comprises an LED epitaxial layer, a bonding layer and a buffer layer, which are sequentially disposed, and the LED epitaxial layer is connected to the metal layer.

3. The LED chip structure of claim 1, wherein the substrate is made of an etchable material.

4. The LED chip structure of claim 1, wherein the substrate is made of silicon.

5. The LED chip structure of claim 2, wherein the bonding layer is made of NiAu, and the outermost layer of the bonding layer is provided with an Au layer.