CN115377256A - A kind of colored conversion LED chip and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of LED preparation, and discloses a colored conversion LED chip and a preparation method thereof, wherein the preparation method comprises the following steps: sequentially forming a light-emitting structure and an electrode structure on a transparent substrate to form an LED wafer; forming a porous structure layer on a silicon substrate, and filling quantum dot materials into the porous structure layer to form a color conversion device; bonding the LED wafer and the color conversion device to form a color conversion combination device; and removing the silicon substrate in the color conversion combination device to form the color conversion LED chip. The invention can replace the red light LED chip in the prior art to be applied to the LED display screen, is beneficial to improving the preparation yield and efficiency of the colored conversion LED chip, and further reduces the production cost of the colored conversion LED chip. In addition, the reserved transparent substrate can enhance the structural strength of the color conversion LED chip and improve the reliability of the color conversion LED chip, and the transparent substrate can enlarge light spots of the color conversion LED chip, so that the light emitting effect is enhanced.

Description

A kind of colored conversion LED chip and preparation method thereof

technical field

The invention relates to the technical field of LED preparation, in particular to a colored conversion LED chip and a preparation method thereof.

Background technique

With the continuous improvement of indoor display application technology, currently used projection, DLP (Digital Light Processing, digital light processing), LCD (Liquid Crystal Display, liquid crystal display), PDP (Plasma Display Panel, plasma display panel) and other display application products can no longer be completely To meet market application requirements, LED (LightEmitting Diode, light-emitting diode) full-color display screens overcome many of the defects of the above-mentioned products. LED chips have better energy-saving effects and higher brightness, and are used in various industries of production and life. Now it has become the first choice for indoor and outdoor large-screen display, such as command center, outdoor advertising screen, conference center and other occasions.

In order to realize the full-color display of the display screen, three kinds of Mini LED chips of red, green and blue are required, and in the COB process, these chips are all flip chips. Since the red LED is a quaternary LED, its substrate is opaque GaAs. When flipping the red LED, it is necessary to bond the red wafer to the sapphire substrate and then remove the GaAs substrate. The process is complicated and the GaAs substrate must be removed. It is easy to cause damage to the light-emitting structure of the red light wafer, resulting in low production efficiency and production yield of flip-chip red LEDs. Therefore, in small-pitch or micro-pitch LED displays, the cost of flip-chip red LEDs accounts for a large Great proportions. In addition, compared with GaN (gallium nitride) materials, the AlInGaP epitaxial layer of red light is brittle and fragile, and device failures caused by epitaxial film peeling often occur during use, which is difficult to meet actual application requirements.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a colored conversion LED chip and a preparation method thereof, which solves the problem in the prior art that the manufacturing efficiency and yield of the red LED chip are low, resulting in high cost.

To achieve the above object, the present invention provides the following technical solutions:

A method for preparing a colored conversion LED chip, comprising:

Form a light-emitting structure and an electrode structure sequentially on a transparent substrate to form an LED wafer;

forming a porous structure layer on a silicon substrate, filling the porous structure layer with quantum dot materials to form a color conversion device;

bonding the LED wafer and the color conversion device to form a color conversion combination device;

The silicon substrate in the color conversion combination device is removed to form a color conversion LED chip.

Optionally, the bonding of the LED wafer and the color conversion device includes:

bonding the porous structure layer of the color conversion device to the transparent substrate of the LED wafer.

Optionally, the forming a porous structure layer on the silicon substrate includes:

forming a gallium nitride layer on the silicon substrate;

A plurality of concave holes are made in the gallium nitride layer to form the porous structure layer.

Optionally, the concave holes are blind holes distributed on the outer surface of the porous structure layer.

Optionally, the bonding of the LED wafer and the color conversion device includes:

The outer surface of the porous structure layer in the color conversion device is bonded to the transparent substrate of the LED wafer.

Optionally, the removal of the silicon substrate in the color conversion combination device includes:

Etching the silicon substrate to expose the porous structure layer.

Optionally, the etching the silicon substrate includes:

The silicon substrate is etched by a wet etching process.

Optionally, the electrode structure includes two electrodes with opposite polarities.

Optionally, forming a light emitting structure and an electrode structure sequentially on a transparent substrate to form an LED wafer further includes:

thinning the transparent substrate.

The present invention also provides a colored conversion LED chip, which is prepared by the preparation method of the colored conversion LED chip described in any one of the above.

Compared with the prior art, the present invention has the following beneficial effects:

The invention provides a colored conversion LED chip and a preparation method thereof. The LED wafer and a color conversion device are bonded to form a colored conversion LED chip with a color conversion function, which can replace the red LED chip of the prior art for application In LED display screens; since there is no need to peel off the transparent substrate in the LED wafer, it can avoid the damage of the LED wafer when peeling off the substrate, which is conducive to improving the preparation yield and efficiency of colored conversion LED chips, thereby reducing Color conversion LED chip production cost.

In addition, the retained transparent substrate can enhance the structural strength of the colored conversion LED chip and improve its reliability, and the transparent substrate can enlarge the light spot of the colored converted LED chip, thereby enhancing the luminous effect.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is a structural schematic diagram of a method for preparing a colored conversion LED chip provided by the present invention;

Fig. 2 is a structural schematic diagram of an LED wafer in a method for preparing a colored conversion LED chip provided by the present invention;

3 is a structural schematic diagram of a color conversion structure in a method for preparing a color conversion LED chip provided by the present invention;

Fig. 4 is a structural schematic diagram of bonding an LED wafer and a color conversion structure in a method for preparing a color conversion LED chip provided by the present invention;

Fig. 5 is a structural schematic diagram after the LED wafer and the color conversion structure are bonded and the silicon substrate is removed in a method for preparing a color conversion LED chip provided by the present invention;

Fig. 6 is a schematic structural diagram of a colored conversion LED chip provided by the present invention.

In the above figure: 100, LED wafer; 101, transparent substrate; 102, light emitting structure; 1031, first electrode; 1032, second electrode; 200, color conversion structure; 201, silicon substrate; 202, porous structure layer ; 203. Quantum dot materials.

Detailed ways

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the following description The embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

It should be understood that in the description of the present invention, specific embodiments are only used to explain the present invention, rather than limit the present invention. Wherein, the exemplary embodiments are described as processes or methods depicted as flowcharts; although the flowcharts describe operations or steps in a certain order, many of the operations or steps can be performed in parallel, concurrently, or are performed simultaneously, and the order of operations can be rearranged. A corresponding process may be terminated when its operations or steps are complete, and may also have additional steps not included in the figures. The aforementioned processes may correspond to methods, functions, procedures, subroutines, subroutines, etc., and the embodiments and features in the embodiments of the present invention may be combined with each other if there is no conflict.

The term "comprising" and its variants used in the present invention are open to include, ie "including but not limited to". The term "based on" is "based at least in part on". The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods; it can be understood that, for the convenience of description, the accompanying drawings only show some but not all structures related to the present invention.

With the continuous improvement of indoor display application technology, currently used projection, DLP (Digital Light Processing, digital light processing), LCD (Liquid Crystal Display, liquid crystal display), PDP (Plasma Display Panel, plasma display panel) and other display application products can no longer be completely Meet market application needs. There are also some defects in various aspects so that it cannot break through the development of technology. And LED (Light Emitting Diode, light-emitting diode) full-color display overcomes the many defects of the above-mentioned products, and has become the first choice for indoor and outdoor large-screen displays, such as command centers, outdoor advertising screens, conference centers and other occasions.

LED chips have good energy-saving effect and high brightness, and are used in various industries of production and life. Usually, the LED display is seamlessly spliced into a large-size display through a certain number of small-size display modules. Among them, one of the common manufacturing methods of the small-pitch display module is Chip On Board (COB for short). In the current process of making small-pitch LED displays using the COB method, the chips used are flip-chip Mini LED chips. In order to realize full-color display, three kinds of Mini LED chips of red, green and blue are needed. However, LED chips in the prior art are usually made of gallium nitride-based materials. Using gallium nitride-based chips to make blue LEDs and green LEDs is a mature process, which is simple to make and use, but red LEDs are quaternary LEDs. , the substrate is opaque GaAs, if you want to obtain flip-chip red LEDs, you need to bond the red wafer to the sapphire substrate and then remove the GaAs substrate, the process is complex, especially in small-pitch or micro-pitch LED displays Among them, the cost of flip-chip red light chips accounts for a large proportion, and the production yield of this process is low. In addition, compared with GaN (gallium nitride) materials, the red AlInGaP epitaxial layer is brittle and fragile, and device failures caused by epitaxial film peeling often occur during use. The above process leads to good flip-chip red LEDs. The efficiency is low and the cost is high, so it cannot meet the application requirements.

Based on the above problems in the prior art, the present invention aims to provide a color-converted LED chip and its preparation scheme, so as to provide a color-switchable color-converted LED chip suitable for small-pitch or micro-pitch LED displays to replace existing Some LED chips.

Please refer to Figure 1 to Figure 6 together, a method for preparing a colored conversion LED chip, including:

S1 , sequentially forming a light emitting structure 102 and an electrode structure on a transparent substrate 101 to form an LED wafer 100 .

Please refer to FIG. 2 , in this step, the transparent substrate 101 is a growth substrate of the LED wafer 100 , specifically a sapphire substrate or a silicon carbide substrate. Adopting the transparent substrate 101 not only facilitates light emission, but also plays a supporting role.

Wherein, the electrode structure includes two electrodes with opposite polarities, specifically the first electrode 1031 and the second electrode 1032 .

In one of the optional implementation manners, in this step, after sequentially forming the light emitting structure 102 and the electrode structure on the transparent substrate 101, further include:

The transparent substrate 101 is thinned.

By thinning the transparent substrate 101 , the thickness of the finally obtained colored conversion LED chip can be made moderate.

S2. Form a porous structure layer 202 on the silicon substrate 201, and fill the porous structure layer 202 with quantum dot material 203 to form a color conversion device.

Please refer to FIG. 3, in this step, a porous structure layer 202 is formed on a silicon substrate 201, specifically including:

Firstly, a gallium nitride layer is formed on the silicon substrate 201 ; then, a plurality of concave holes are made in the gallium nitride layer to form the porous structure layer 202 . Among them, the production of the concave hole can be realized by methods such as etching or laser etching. Specifically, the gallium nitride layer is n-type gallium nitride, and a plurality of concave holes are formed by electrochemical etching.

Further, the concave holes are blind holes distributed on the outer surface of the porous structure layer 202 , so that the filled quantum dot material 203 can be exposed on the outer surface of the porous structure layer 202 . In order to realize the fixing of the quantum dot material 203 in the concave hole, the quantum dot material 203 can adopt a curable material, such as photocuring or thermal curing, etc., the quantum dot material 203 of the fluid is filled in the concave hole, and then the quantum dot material 203 is curing to ensure the fixation of the quantum dot material 203 in the concave hole.

In this embodiment, light conversion can be realized by using quantum dot material 203; for example, when filling red light quantum dot material 203, blue light can be converted into red light, so that it can be used as a red light LED chip; when filling green light quantum dot material When the material 203 is used, blue light can be converted into green light, so that it can be used as a green LED chip.

S3, bonding the LED wafer 100 and the color conversion device to form a color conversion combination device.

Please refer to Fig. 4, in this step, when bonding the LED wafer 100 and the color conversion device, the porous structure layer 202 of the color conversion device is bonded to the transparent substrate 101 of the LED wafer 100; specifically, the color conversion The outer surface of the porous structure layer 202 in the device is bonded to the transparent substrate 101 of the LED wafer 100, which is conducive to shortening the distance between the quantum dot material 203 and the light-emitting structure 102 in the LED wafer 100, thereby enhancing the luminous effect of the colored conversion LED chip .

S4, removing the silicon substrate 201 in the color conversion combination device to form a color conversion LED chip.

Please refer to FIG. 5 and FIG. 6 , in this step, the silicon substrate 201 is removed by etching to expose the porous structure layer 202 .

Specifically, the silicon substrate 201 of the color conversion device is etched by a wet etching process to achieve the effect of a moderate thickness of the color conversion combination device, which can avoid the damage of the LED wafer 100 by the laser lift-off growth substrate process of the conventional method .

The color conversion LED chip obtained through this step includes the following structures in sequence: a porous structure layer 202 , a transparent substrate 101 , a light emitting structure 102 and an electrode structure. By retaining the growth substrate of the LED wafer 100, the colored conversion LED chip can have a certain structural strength, and the formed light spot can also be enlarged (the light-emitting angle of the LED chip is an obtuse angle), thereby effectively enhancing the color conversion LED chip. glow effect. At the same time, the reservation of the transparent substrate 101 makes the color conversion LED chip have a certain thickness, but not too thick, so that it can realize relatively simple transfer under the existing conditions and apply it to the LED display screen.

Please refer to FIG. 6 again. Based on the foregoing embodiments, the embodiment of the present invention also provides a colored conversion LED chip, which is manufactured by any one of the methods for preparing a colored conversion LED chip.

Specifically, the structures included in the color conversion LED chip are: a porous structure layer 202, a transparent substrate 101, a light emitting structure 102 and an electrode structure.

Retaining the growth substrate of the LED wafer 100 can make the colored conversion LED chip have a certain structural strength, and can also expand the formed light spot (the light emitting angle of the LED chip is an obtuse angle), thereby effectively enhancing the light emission of the colored conversion LED chip Effect. At the same time, the reservation of the transparent substrate 101 makes the color conversion LED chip have a certain thickness, but not too thick, so that it can realize relatively simple transfer under the existing conditions and apply it to the LED display screen.

Based on the above-mentioned embodiments, the present invention bonds the LED wafer 100 and the color conversion device to form a color conversion LED chip with a color conversion function, which can replace the red LED chip of the prior art and be applied to an LED display; Since there is no need to peel off the transparent substrate 101 in the LED wafer 100, it can avoid the damage of the LED wafer 100 when peeling off the substrate, which is conducive to improving the production yield and efficiency of the colored conversion LED chip, thereby reducing the cost of the color conversion LED chip. Chip production costs.

In addition, the retained transparent substrate 101 can enhance the structural strength of the colored conversion LED chip and improve its reliability, and the transparent substrate 101 can enlarge the light spot of the colored converted LED chip, thereby enhancing the luminous effect.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A method for preparing a colored conversion LED chip, characterized in that, comprising: Form a light-emitting structure and an electrode structure sequentially on a transparent substrate to form an LED wafer; forming a porous structure layer on a silicon substrate, filling the porous structure layer with quantum dot materials to form a color conversion device; bonding the LED wafer and the color conversion device to form a color conversion combination device; The silicon substrate in the color conversion combination device is removed to form a color conversion LED chip. 2. The method for preparing a colored conversion LED chip according to claim 1, wherein the bonding of the LED wafer and the color conversion device comprises: bonding the porous structure layer of the color conversion device to the transparent substrate of the LED wafer. 3. The method for preparing a colored conversion LED chip according to claim 1, wherein said forming a porous structure layer on a silicon substrate comprises: forming a gallium nitride layer on the silicon substrate; A plurality of concave holes are made in the gallium nitride layer to form the porous structure layer. 4. The method for preparing a colored conversion LED chip according to claim 3, wherein the concave holes are blind holes distributed on the outer surface of the porous structure layer. 5. The method for preparing a colored conversion LED chip according to claim 4, wherein the bonding of the LED wafer and the color conversion device comprises: The outer surface of the porous structure layer in the color conversion device is bonded to the transparent substrate of the LED wafer. 6. The method for preparing a colored conversion LED chip according to claim 1, wherein the removal of the silicon substrate in the color conversion combined device comprises: Etching the silicon substrate to expose the porous structure layer. 7. The method for preparing a colored conversion LED chip according to claim 6, wherein said etching said silicon substrate comprises: The silicon substrate is etched by a wet etching process. 8. The method for manufacturing a colored conversion LED chip according to claim 1, wherein the electrode structure comprises two electrodes with opposite polarities. 9. The method for preparing a colored conversion LED chip according to claim 1, wherein said sequentially forming a light-emitting structure and an electrode structure on a transparent substrate to form an LED wafer further comprises: thinning the transparent substrate. 10. A colored conversion LED chip, characterized in that it is produced by the method for preparing a colored conversion LED chip according to any one of claims 1 to 9.

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