Method for improving brightness of LED chip and novel LED chip

Abstract

The invention relates to the technical field of light emitting diode manufacturing, in particular to a method for improving the brightness of an LED chip and a novel LED chip. According to the method, the light emitted by the single LED wafer is focused through the light reflecting coating on the outer side of the single LED wafer to improve the brightness of the LED chip, and the light reflecting coating wraps the other faces of the single LED wafer except the side where the light rays are emitted. The light rays emitted by the LED chip are reflected by the reflective plating layer plated on the side surface of the single LED wafer, so that the LED chip can only emit the light rays from one surface, and the luminance of the LED chip is effectively improved. The LED chip comprises an electrode, a light-emitting area and a structural layer, a back gold layer is arranged on the side, away from the electrode and the light-emitting area, of the structural layer, and the side, provided with the back gold layer, of the structural layer and the adjacent side face are plated with side wall evaporation layers. And one side and the adjacent side surface of the back gold layer are plated with the side wall evaporation layer, so that the light condensation effect of the LED chip is improved, and the brightness of the LED chip is improved.

Description

Technical Field

[0001] The invention relates to the technical field of light emitting diode manufacturing, and in particular to a method for improving the brightness of an LED chip and a novel LED chip. Background Art

[0002] Light emitting diodes, or LEDs for short, have the advantages of high luminescence rate, low energy consumption, and long life. They are widely used in various light source fields such as household lighting, outdoor lighting, medical lighting, and displays. Like ordinary diodes, light emitting diodes are composed of a PN junction and also have unidirectional conductivity. When a forward voltage is applied to the light emitting diode, the holes injected from the P region into the N region and the electrons injected from the N region into the P region recombine with the electrons in the N region and the holes in the P region within a few microns near the PN junction, respectively, to produce spontaneously radiated fluorescence. The energy states of electrons and holes in different semiconductor materials are different. When electrons and holes recombine, the amount of energy released is different. The more energy released, the shorter the wavelength of the emitted light. Commonly used are diodes that emit red, green, or yellow light. The reverse breakdown voltage of a light emitting diode is greater than 5 volts, and its forward volt-ampere characteristic curve is very steep. When used, a current limiting resistor must be connected in series to control the current passing through the diode.

[0003] At present, improving the luminous efficiency of LED chips is still the focus of current industry development. When the light-emitting diode is lit, the light emitted from the light-emitting area will be emitted at multiple angles. Part of the light is confined inside the light-emitting diode due to total reflection and is eventually absorbed by the electrode or the light-emitting layer, making it difficult to increase the brightness. There is a metal layer on the back of the existing LED, so most of the light loss is through the side wall loss. Summary of the invention

[0004] In order to solve the problem that the brightness cannot be concentrated due to scattered light when an LED chip emits light, the present invention provides a method for improving the brightness of an LED chip and a novel LED chip.

[0005] On the one hand, the present invention provides a method for improving the brightness of an LED chip using the following technical solution:

[0006] A method for improving the brightness of an LED chip, using a reflective coating on the outer side of a single LED chip to focus the light emitted by the single LED chip to improve the brightness of the LED chip, wherein the reflective coating is wrapped around the other surfaces of the single LED chip except the side emitting light.

[0007] The reflective coating on the side of a single LED chip is used to reflect the light emitted by the LED chip, so that the LED chip can only emit light from one side, effectively improving the brightness of the LED chip.

[0008] Furthermore, the step of coating the LED wafer with a reflective coating comprises:

[0009] Paste the light-emitting side of the singulated LED chip onto the substrate;

[0010] Then, a reflective coating is evaporated on the surface of the pasted LED chip;

[0011] Wait for the reflective coating to firmly adhere to the surface of the LED chip, and then remove the LED chip from the substrate;

[0012] Finally, power on and test the light-emitting effect of a single LED chip.

[0013] Sticking the light-emitting side of the LED chip to the substrate is beneficial to prevent the evaporated layer from adhering to the light-emitting side during subsequent evaporation and hindering the light emission. The reflective material is effectively and firmly attached to the surface of the LED chip through evaporation. Powering on and testing the light-emitting effect of a single LED chip is beneficial to checking the evaporation effect and defective products.

[0014] Furthermore, the substrate adopts a sapphire substrate, and the specific steps of pasting the LED chip on the substrate include:

[0015] Clean the surface of the sapphire substrate;

[0016] Then, a layer of photosensitive adhesive is evenly coated on the cleaned sapphire substrate surface;

[0017] Singulating the LED wafer into singulated LED chips arranged at intervals;

[0018] Paste the singulated LED chip onto the photosensitive adhesive and leave it for 10 minutes;

[0019] Finally, a UV curing machine is used to irradiate the sapphire substrate coated with the photosensitive adhesive to cure the photosensitive adhesive.

[0020] The photosensitive adhesive can conveniently control the solidification and liquefaction of the colloid in a low temperature environment, thereby facilitating the fixing of singulated LED chips and reducing damage to the singulated LED chips.

[0021] Furthermore, after the LED wafer is singulated, the intervals between the singulated LED chips arranged at intervals are enlarged by 1.1 times;

[0022] After the UV curing machine is used to irradiate the side of the sapphire substrate coated with the photosensitive adhesive, the UV curing machine is then used to irradiate the side of the sapphire substrate not coated with the photosensitive adhesive, so that the photosensitive adhesive is fully and evenly cured.

[0023] Increasing the gap between singulated LED chips is beneficial for uniform evaporation on the surface of the singulated LED chips during subsequent evaporation, thereby reducing mutual adhesion.

[0024] Furthermore, before a reflective coating layer is evaporated on the surface of the LED wafer, the sapphire substrate on which the singulated LED chips are pasted is first cleaned and dried.

[0025] Cleaning and drying are helpful to remove dirt on the surface of sapphire substrate and avoid affecting the adhesion of photosensitive adhesive.

[0026] Furthermore, the specific steps of cleaning and drying the sapphire substrate on which the singulated LED chips are attached include:

[0027] First, rinse the sapphire substrate with the singulated LED chips attached;

[0028] Then dry the sapphire substrate with the singulated LED chips attached to it and wash it in an isopropyl alcohol solution;

[0029] Finally, a hot nitrogen dryer is used to dry the sapphire substrate with the singulated LED chips attached.

[0030] Flushing with water helps to rinse away obvious dirt, and isopropyl alcohol solution is used to clean water-insoluble organic micro-impurities, effectively and thoroughly cleaning them. Drying with a hot nitrogen dryer helps to reduce secondary contamination of the sapphire substrate.

[0031] Furthermore, when a reflective coating is evaporated on the surface of the LED chip, the sapphire substrate with the singulated LED chip pasted thereon is first mounted on a vapor deposition chuck, and then vapor deposition is performed at room temperature to form a sidewall vapor deposition layer, wherein the sidewall vapor deposition layer material includes titanium and gold, and finally the reflective coating is formed after the sidewall vapor deposition layer is firmly fixed.

[0032] Evaporation at room temperature is beneficial to protecting the LED chip and preventing high or low temperature from affecting and damaging the LED chip.

[0033] Furthermore, when removing the LED chip from the substrate, first stick the side of the sapphire substrate with the singulated LED chip onto the white film, then place the sapphire substrate, the singulated LED chip and the white film into a UV glue dissolving machine to decompose the photosensitive glue, and finally use the white film to remove the singulated LED chip from the sapphire substrate.

[0034] The white film is used to facilitate the removal of the singulated LED chips from the sapphire substrate.

[0035] Furthermore, after the singulated LED chip on the sapphire substrate is removed by using the white film, the residual photosensitive adhesive on the singulated LED chip is cleaned, and finally the singulated LED chip from which the residual photosensitive adhesive has been cleaned is placed in a hot nitrogen dryer for drying.

[0036] Clean the residual photosensitive adhesive on the singulated LED chips, effectively improving the quality of the finished products of the singulated LED chips.

[0037] On the other hand, the present invention provides a novel LED chip adopting the following technical solution:

[0038] A novel LED chip comprises an electrode, a light-emitting area and a structural layer, wherein the electrode, the light-emitting area and the structural layer are interconnected to form a light-emitting diode structure, a back gold layer is arranged on the side of the structural layer away from the electrode and the light-emitting area, and a side wall vapor-deposited layer is plated on the side of the structural layer provided with the back gold layer and the adjacent side surface.

[0039] One side of the back gold layer and the adjacent side surface are coated with a sidewall vapor deposition layer, which is beneficial to improving the focusing effect of the LED chip, thereby improving the brightness of the LED chip.

[0040] In summary, the present invention has the following beneficial technical effects:

[0041] 1. Use the reflective coating on the side of a single LED chip to reflect the light emitted by the LED chip, so that the LED chip can only emit light from one side, effectively improving the brightness of the LED chip. Paste the emitting side of the LED chip on the substrate, which is beneficial to prevent the evaporation layer from adhering to the emitting side during subsequent evaporation and hindering the light emission. Through evaporation, the reflective material is effectively firmly attached to the surface of the LED chip. Power on and test the luminous effect of a single LED chip, which is beneficial to check the evaporation effect and defective products.

[0042] 2. Photosensitive adhesive is convenient for controlling the solidification and liquefaction of the colloid under low temperature environment, convenient for fixing the singulated LED chip and reducing the damage to the singulated LED chip. Increasing the gap between the singulated LED chips is conducive to uniform evaporation on the surface of the singulated LED chip during subsequent evaporation, reducing mutual adhesion. Cleaning and drying are conducive to removing dirt on the surface of the sapphire substrate to avoid affecting the adhesion of the photosensitive adhesive. Flushing is conducive to rinsing away obvious dirt. Isopropyl alcohol solution is used to clean water-insoluble organic micro-impurities and effectively carry out thorough cleaning. Drying with a hot nitrogen dryer is conducive to reducing secondary pollution to the sapphire substrate. Evaporation at room temperature is conducive to protecting the LED chip and avoiding the influence and damage of high temperature or low temperature on the LED chip. The white film is convenient for removing the singulated LED chip from the sapphire substrate, cleaning the residual photosensitive adhesive on the singulated LED chip, and effectively improving the finished product quality of the singulated LED chip.

[0043] 3. One side of the back gold layer and the adjacent side are coated with a sidewall vapor deposition layer, which is beneficial to improving the focusing effect of the LED chip, thereby increasing the brightness of the LED chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the evaporation installation structure of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of the new LED chip of the present invention.

[0046] Description of reference numerals:

[0047] 1. Sapphire substrate, 2. Photosensitive adhesive, 3. Single LED chip, 4. Side wall evaporation layer, 5. Back gold layer, 6. Electrode, 7. Light-emitting area, 8. Structural layer. DETAILED DESCRIPTION

[0048] The following will be combined with the attached Figure 1-Figure 2 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] Embodiment 1:

[0051] The embodiment of the present invention discloses a method for improving the brightness of an LED chip, referring to Figure 1 and Figure 2 , the light emitted by a single LED chip is focused by using a reflective coating on the outer side of a single LED chip to improve the brightness of the LED chip, and the reflective coating is wrapped on the other surfaces of the single LED chip except the side that emits light.

[0052] Embodiment 2:

[0053] On the basis of Example 1, add:

[0054] Reference Figure 1 and Figure 2 The step of coating the LED chip with a reflective coating comprises:

[0055] Paste the light-emitting side of the singulated LED chip onto the substrate;

[0056] Then, a reflective coating is evaporated on the surface of the pasted LED chip;

[0057] Wait for the reflective coating to firmly adhere to the surface of the LED chip, and then remove the LED chip from the substrate;

[0058] Finally, power on and test the light-emitting effect of a single LED chip.

[0059] The substrate adopts a sapphire substrate 1, and the specific steps of pasting the LED chip on the substrate include:

[0060] Clean the surface of the sapphire substrate 1;

[0061] Then, a layer of photosensitive adhesive 2 is evenly coated on the surface of the cleaned sapphire substrate 1;

[0062] Cutting the LED wafer into individual LED chips 3 arranged at intervals;

[0063] Paste the singulated LED chip 3 onto the photosensitive adhesive 2 and leave it for 10 minutes;

[0064] Finally, a UV curing machine is used to irradiate the side of the sapphire substrate 1 coated with the photosensitive adhesive 2 to cure the photosensitive adhesive 2.

[0065] When the singulated LED chips 3 are pasted on the photosensitive adhesive 2 , the electrodes 6 and the light-emitting areas 7 are completely immersed in the photosensitive adhesive 2 .

[0066] After the LED wafer is singulated, the intervals between the singulated LED chips 3 arranged at intervals are enlarged by 1.1 times;

[0067] After the UV curing machine is used to irradiate the side of the sapphire substrate 1 coated with the photosensitive adhesive 2, the UV curing machine is then used to irradiate the side of the sapphire substrate 1 not coated with the photosensitive adhesive 2, so that the photosensitive adhesive 2 is fully and evenly cured.

[0068] Before a reflective coating layer is evaporated on the surface of the LED wafer, the sapphire substrate 1 on which the singulated LED chips 3 are attached is first cleaned and dried.

[0069] The specific steps of cleaning and drying the sapphire substrate 1 on which the singulated LED chips 3 are attached include:

[0070] First, rinse the sapphire substrate 1 with the singulated LED chips 3 attached thereto;

[0071] Then, the sapphire substrate 1 with the singulated LED chips 3 attached thereto is dried and then placed in an isopropyl alcohol solution for cleaning;

[0072] Finally, the sapphire substrate 1 with the singulated LED chips 3 attached thereto is dried using a hot nitrogen drying machine.

[0073] When a reflective coating is evaporated on the surface of the LED chip, the sapphire substrate 1 with the singulated LED chip 3 pasted thereon is first mounted on a vapor deposition chuck, and then vapor deposition is performed at room temperature to form a sidewall vapor deposition layer 4, wherein the sidewall vapor deposition layer 4 includes titanium and gold. Finally, the reflective coating is formed after the sidewall vapor deposition layer 4 is firmly fixed.

[0074] When the side wall deposition layer 4 is formed by evaporation, a layer of titanium is firstly evaporated, and then a layer of gold is evaporated.

[0075] When removing the LED chip from the substrate, first stick the side of the sapphire substrate 1 with the singulated LED chip 3 onto the white film, then place the sapphire substrate 1, the singulated LED chip 3 and the white film into a UV glue dissolving machine to decompose the photosensitive glue 2, and finally use the white film to remove the singulated LED chip 3 on the sapphire substrate 1.

[0076] After the singulated LED chip 3 on the sapphire substrate 1 is removed by using the white film, the residual photosensitive adhesive 2 on the singulated LED chip 3 is cleaned, and finally the singulated LED chip 3 from which the residual photosensitive adhesive 2 has been cleaned is placed in a hot nitrogen dryer for drying.

[0077] Embodiment 3:

[0078] The embodiment of the present invention discloses a new type of LED chip, referring to Figure 1 and Figure 2 , including an electrode 6, a light-emitting area 7 and a structural layer 8, wherein the electrode 6, the light-emitting area 7 and the structural layer 8 are interconnected to form a light-emitting diode structure, and a back gold layer 5 is provided on the side of the structural layer 8 away from the electrode 6 and the light-emitting area 7, and a side wall vapor-deposited layer 4 is plated on the side of the structural layer 8 provided with the back gold layer 5 and the adjacent side surface.

[0079] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for improving the brightness of an LED chip, characterized in that: The light emitted by a single LED chip is focused by using a reflective coating on the outer side of a single LED chip to improve the brightness of the LED chip. The reflective coating is wrapped on the other surfaces of the single LED chip except the side emitting light.

2. A method for improving the brightness of an LED chip according to claim 1, characterized in that: The step of coating the LED chip with a reflective coating layer comprises: Paste the light-emitting side of the singulated LED chip onto the substrate; Then, a reflective coating is evaporated on the surface of the pasted LED chip; Wait for the reflective coating to firmly adhere to the surface of the LED chip, and then remove the LED chip from the substrate; Finally, power on and test the light-emitting effect of a single LED chip.

3. A method for improving the brightness of an LED chip according to claim 2, characterized in that: The substrate adopts a sapphire substrate (1), and the specific steps of pasting the LED chip on the substrate include: Cleaning the surface of the sapphire substrate (1); Then, a layer of photosensitive adhesive (2) is evenly coated on the surface of the cleaned sapphire substrate (1); Singulating the LED wafer into singulated LED chips (3) arranged at intervals; Paste the singulated LED chip (3) onto the photosensitive adhesive (2) and leave it for 10 minutes; Finally, a UV curing machine is used to irradiate the side of the sapphire substrate (1) coated with the photosensitive adhesive (2) to cure the photosensitive adhesive (2).

4. A method for improving the brightness of an LED chip according to claim 3, characterized in that: After the LED wafer is singulated, the intervals between the singulated LED chips (3) arranged at intervals are enlarged by 1.1 times; After the UV curing machine is used to irradiate the side of the sapphire substrate (1) coated with the photosensitive adhesive (2), the UV curing machine is then used to irradiate the side of the sapphire substrate (1) not coated with the photosensitive adhesive (2), so that the photosensitive adhesive (2) is fully and evenly cured.

5. The method for improving the brightness of an LED chip according to claim 2, characterized in that: Before a reflective coating layer is evaporated on the surface of the LED wafer, the sapphire substrate (1) on which the singulated LED chips (3) are attached is first cleaned and dried.

6. A method for improving the brightness of an LED chip according to claim 5, characterized in that: The specific steps of cleaning and drying the sapphire substrate (1) on which the singulated LED chips (3) are attached include: First, the sapphire substrate (1) on which the singulated LED chips (3) are attached is rinsed with water; Then, the sapphire substrate (1) on which the singulated LED chips (3) are attached is dried and then placed in an isopropyl alcohol solution for cleaning; Finally, a hot nitrogen drying machine is used to dry the sapphire substrate (1) on which the singulated LED chips (3) are attached.

7. A method for improving the brightness of an LED chip according to claim 2, characterized in that: When a reflective coating layer is evaporated on the surface of the LED chip, the sapphire substrate (1) with the singulated LED chip (3) attached is first mounted on a vapor deposition chuck, and then vapor deposition is performed at room temperature to form a sidewall vapor deposition layer (4), wherein the sidewall vapor deposition layer (4) is made of titanium and gold, and finally the reflective coating layer is formed after the sidewall vapor deposition layer (4) is firmly formed.

8. The method for improving the brightness of an LED chip according to claim 2, characterized in that: When removing the LED wafer from the substrate, the sapphire substrate (1) is firstly pasted with one side of the singulated LED chip (3) onto the white film, and then the sapphire substrate (1), the singulated LED chip (3) and the white film are placed in a UV glue dissolving machine to decompose the photosensitive glue (2), and finally the singulated LED chip (3) on the sapphire substrate (1) is removed using the white film.

9. A method for improving the brightness of an LED chip according to claim 8, characterized in that: After the singulated LED chip (3) on the sapphire substrate (1) is removed by using the white film, the residual photosensitive adhesive (2) on the singulated LED chip (3) is cleaned, and finally the singulated LED chip (3) from which the residual photosensitive adhesive (2) has been cleaned is placed in a hot nitrogen dryer for drying.

10. A novel LED chip, comprising an electrode (6), a light-emitting area (7) and a structural layer (8), wherein the electrode (6), the light-emitting area (7) and the structural layer (8) are connected to each other to form a light-emitting diode structure, and a back gold layer (5) is provided on a side of the structural layer (8) away from the electrode (6) and the light-emitting area (7), characterized in that: The structural layer (8) is provided with a side surface of the back gold layer (5) and an adjacent side surface coated with a side wall vapor deposition layer (4).

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