A method for manufacturing an LED chip with low cavity ratio

Abstract

The application discloses a kind of low cavity rate LED chip manufacturing method, it is related to light-emitting diode technical field, including the following steps: on epitaxial wafer according to LED chip process flow Manufacturing insulating film layer and metal film layer;After forming in each layer insulating film layer, corresponding insulating film layer is immersed in insulator nanoparticle fluid with epitaxial wafer and is heated and ultrasonic oscillation treatment;Then it is taken out and is cleaned, and is placed in N2 atmosphere and is high-temperature annealing treatment;When manufacturing each layer metal film layer, single alloy material ingot is used as single material source and is evaporated, or multiple metal single material ingot is used as multiple material source and is evaporated simultaneously to form each layer metal film layer.The method of the application reduces the cavity rate of film layer by heating, ultrasonic oscillation and high-temperature annealing treatment by immersing insulating film layer in nanoparticle fluid;The cavity rate of film layer is reduced by special PVD process to make metal film layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light emitting diode, in particular to a method for manufacturing low-cavity-rate LED chip. BACKGROUND

[0002] Figure 1 The structure diagram of the prior art LED chip is shown, the sidewall protection layer 11, the first passivation layer 12, the second passivation layer 13 and other insulating film layers are generally made by chemical vapor deposition (CVD) process, and the N-type current conducting layer 21, the P-type current conducting layer 22, the N-type electrode pad 23, the P-type electrode pad 24 and other metal film layers are generally made by physical vapor deposition (PVD) process.

[0003] However, due to the volatility of the deposition process and the aging of the equipment, the deposited insulating film layers and metal film layers will inevitably have film layer cavities, and the cavities will become more and more, making the film layer densification worse and worse, leading to more and more serious leakage of LED chip products, and also leading to the manufacturing yield of flip-chip LED chip products. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a method for manufacturing low-cavity-rate LED chip, which enhances the film layer densification, reduces the film layer cavity rate and the product leakage rate by heating, ultrasonic oscillation and high-temperature annealing treatment of the insulating film layer in the nano-particle fluid; and reduces the film layer cavity rate and improves the product reliability by special PVD process to make the metal film layer.

[0005] The present application provides a method for manufacturing low-cavity-rate LED chip, comprising the following steps:

[0006] 1) manufacturing insulating film layers and metal film layers on the epitaxial wafer according to the LED chip process flow;

[0007] 2) after the formation of each layer of insulating film layer, immersing the corresponding insulating film layer together with the epitaxial wafer in the insulator nano-particle fluid for heating and ultrasonic oscillation treatment; cleaning the epitaxial wafer with insulating film layer after heating and ultrasonic oscillation treatment, and placing it in N2 atmosphere for high-temperature annealing treatment;

[0008] 3) when manufacturing each layer of metal film layer, using a single alloy material ingot as a single material source for evaporation deposition to form each layer of metal film layer, or using multiple metal single material ingots as multiple material sources for simultaneous evaporation to form each layer of metal film layer.

[0009] Specifically, the insulating film layer is one or a combination of more than one of silicon dioxide film layer, silicon nitride film layer and silicon carbide film layer.

[0010] Specifically, the insulator nanoparticle fluid is formed by dispersing insulator nanoparticles in isopropyl alcohol or acetone; the insulator nanoparticles are one or a combination of silicon dioxide nanoparticles, silicon nitride nanoparticles and silicon carbide nanoparticles; and the insulator nanoparticles have a particle size of 1-10 nm.

[0011] Specifically, the heating temperature is 40-350 DEG C, the heating treatment time is 10-30 min; the ultrasonic oscillation frequency is 10-30 MHz, and the ultrasonic oscillation treatment time is 10-30 min.

[0012] Specifically, the cleaning of the epitaxial wafer with an insulating film layer after heating and ultrasonic oscillation treatment comprises: first, washing the surface of the epitaxial wafer with an insulating film layer with acetone or isopropyl alcohol, and then placing the epitaxial wafer with an insulating film layer in deionized water at 60-90 DEG C for ultrasonic cleaning for 30-60 min, the ultrasonic cleaning frequency being 10-30 MHz.

[0013] Specifically, the N2 flow rate is 10-100 sccm, and the N2 gas pressure is 0.01-0.1 mtorr.

[0014] Specifically, the high-temperature annealing treatment comprises: placing the cleaned epitaxial wafer with an insulating film layer in a temperature condition of 200-300 DEG C for 10-30 min, and then cooling to room temperature.

[0015] Specifically, the alloy material ingot comprises an aluminum-copper material ingot, a nickel-copper material ingot, a titanium-nickel material ingot or a titanium-platinum material ingot.

[0016] Specifically, the alloy material ingot is formed by uniformly mixing metal elementary particles with a particle size of 1-10 nm and then pressure casting, and the melting points of different kinds of the metal elementary particles differ by no more than 500 DEG C.

[0017] Specifically, the metal elementary material ingot comprises an aluminum ingot, a copper ingot, a nickel ingot, a titanium ingot or a platinum ingot.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The insulating film layer is immersed in the corresponding insulator nanoparticle fluid, heated and ultrasonically oscillated, so that the insulator nanoparticles are fully embedded in the cavities in the insulating film layer, and then high-temperature annealing treatment is performed, so that the insulator nanoparticles and the insulating film layer are recrystallized and tightly combined, the cavities in the insulating film layer are filled, the compactness of the insulating film layer is enhanced, the stress in the insulating film layer is reduced, and finally the leakage rate of the LED chip product is reduced and the manufacturing yield of the LED chip product is improved.

[0020] The special PVD process is used to mix different metal single element particles fully and uniformly, and the special alloy material ingot is formed by pressure casting to be a single material source for evaporation, or each metal single element material ingot is respectively loaded into a corresponding evaporation source, and then the multiple material sources are simultaneously evaporated to form a metal film layer which is formed by mutual embedding of the metal elements, the metal elements are well adhered to each other, there is no crack, the stress in the metal film layer is reduced, the void rate of the metal film layer is greatly reduced, and the reliability of the product is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of an existing LED chip;

[0022] Figure 2 is a flowchart of a manufacturing method of a low-void-rate LED chip in an embodiment of the present application.

[0023] In the drawings, 11 is a sidewall protection layer, 12 is a primary passivation layer, 13 is a secondary passivation layer, 21 is an N-type current conductive layer, 22 is a P-type current conductive layer, 23 is an N-type electrode pad, and 24 is a P-type electrode pad. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0025] Embodiment one:

[0026] Figure 2 A flowchart of a manufacturing method of a low-void-rate LED chip in an embodiment of the present application is shown, including the following steps:

[0027] S100, forming an insulating film layer and a metal film layer on an epitaxial wafer according to an LED chip process flow;

[0028] S211, after the insulating film layer is formed, heating and ultrasonic oscillation treatment are performed in an insulator nanoparticle fluid;

[0029] After each layer of the insulating film layer is formed, the corresponding insulating film layer is immersed in the insulator nanoparticle fluid together with the epitaxial wafer for heating and ultrasonic oscillation treatment, so that the insulator nanoparticles are fully embedded in the voids in the insulating film layer;

[0030] S212, cleaning;

[0031] The epitaxial wafer with the insulating film layer after the heating and ultrasonic oscillation treatment is cleaned to remove the excess insulating nanoparticle fluid;

[0032] S213, high-temperature annealing treatment in N2 atmosphere;

[0033] The cleaned epitaxial wafer with the insulating film layer is subjected to high-temperature annealing treatment in N2 atmosphere to make the insulating nanoparticles in the hollows and the insulating film layer recrystallize and tightly bond.

[0034] The insulating film layer is immersed in the corresponding insulating nanoparticle fluid and heated and ultrasonically oscillated to make the insulating nanoparticles fully embedded in the hollows in the insulating film layer, and then subjected to high-temperature annealing treatment to make the insulating nanoparticles and the insulating film layer recrystallize and tightly bond, fill the hollows in the insulating film layer, enhance the compactness of the insulating film layer, and reduce the stress in the insulating film layer, thereby reducing the leakage rate of the LED chip product and improving the manufacturing yield of the LED chip product.

[0035] S221, using a single alloy material ingot as a single material source to perform evaporation deposition to form a metal film layer, or using multiple metal single-element material ingots as multiple material sources to simultaneously perform evaporation deposition to form a metal film layer;

[0036] In the production of each layer of metal film layer, a single alloy material ingot is used as a single material source to perform evaporation deposition to form each layer of metal film layer, or multiple metal single-element material ingots are used as multiple material sources to simultaneously perform evaporation deposition to form each layer of metal film layer.

[0037] The metal film layer is generally produced by physical vapor deposition (PVD) process, which is a process of depositing metal single-element particles layer by layer. Fluctuations in parameters such as power and plating rate during deposition can cause metal hollows.

[0038] A special PVD process is used to produce the metal film layer. Different kinds of metal single-element particles are fully and uniformly mixed and pressure-cast to form a specific alloy material ingot as a single material source for evaporation deposition, or each metal single-element material ingot is loaded into a respective evaporation source, and then multiple material sources are simultaneously evaporated to form a metal film layer composed of several metal elements embedded in each other. These metal elements adhere well to each other without cracks, reducing the stress in the metal film layer and significantly reducing the hollow rate of the metal film layer, thereby improving the reliability of the product.

[0039] The multiple metal single material ingots are used as multiple material sources to evaporate simultaneously, so that the content, particle size, thickness and the like of multiple materials can be accurately controlled, but the process requirement is extremely high, a special machine is required to realize, the manufacturing cost is extremely high, and the process adaptability is low; the specific alloy material ingot in the form of powder metallurgy is used as a single material source to evaporate, the manufacturing cost is low, the current process requirement is met, and the process adaptability is high.

[0040] Embodiment two:

[0041] S100. Forming an insulating film layer and a metal film layer on the epitaxial wafer according to the LED chip process flow;

[0042] S211. After the insulating film layer is formed, the insulating film layer is immersed in an insulator nanoparticle fluid for heating and ultrasonic oscillation treatment;

[0043] The insulating film layer is one or a combination of a silicon dioxide film layer, a silicon nitride film layer, and a silicon carbide film layer; after each insulating film layer is formed, the corresponding insulating film layer is immersed in an insulator nanoparticle fluid together with the epitaxial wafer for heating and ultrasonic oscillation treatment.

[0044] The insulator nanoparticle fluid is formed by dispersing insulator nanoparticles in isopropyl alcohol or acetone; the insulator nanoparticles can be uniformly dispersed in an organic solvent such as isopropyl alcohol or acetone and are not prone to agglomeration; the specific organic solvent used depends on the concentration and stability of the dispersion of the insulator nanoparticles; preferably, isopropyl alcohol is used, which has a high dispersible concentration and high stability in isopropyl alcohol. The insulator nanoparticles are one or a combination of silicon dioxide nanoparticles, silicon nitride nanoparticles, and silicon carbide nanoparticles, corresponding to the material of the insulating film layer; the particle size of the insulator nanoparticles is 1-10 nm, and the insulator nanoparticles with this particle size can diffuse into the cavities of the insulating film layer.

[0045] The heating temperature is 40-350°C, preferably 100-350°C; if the heating temperature is lower than 40°C, the rate of diffusion of the insulator nanoparticles into the cavities of the insulating film layer is slow; if the heating temperature exceeds 350°C, other film layers will be damaged and deteriorated; when the heating temperature is lower than 100°C, water bath heating can be used, or when the heating temperature is lower than 200°C, oil bath heating can be used, so that the uniformity of the temperature is high; when the heating temperature is 40-350°C, an electric heating jacket can also be used for heating, which is convenient and fast.

[0046] The heating treatment time is 10-30 min. If the heating treatment time is too short, the process of the insulator nanoparticles diffusing into the cavities of the insulating film layer is insufficient, and the filling rate of the cavities is low. If the heating treatment time is too long, time and energy are wasted.

[0047] The frequency of the ultrasonic oscillation is 10-30 MHz, preferably 15-25 MHz. If the frequency of the ultrasonic oscillation is lower than 10 MHz, the movement of the insulator nanoparticles is slow, the diffusion effect is poor, and it is relatively difficult to fully fill the cavities of the insulating film layer. If the frequency of the ultrasonic oscillation is higher than 30 MHz, other film layers are easily broken and peeled off.

[0048] The treatment time of the ultrasonic oscillation is 10-30 min. The ultrasonic oscillation treatment can be performed simultaneously with the heating treatment, or before or after the heating treatment. Preferably, the heating treatment and the ultrasonic oscillation treatment are performed simultaneously. Both the heating treatment and the ultrasonic oscillation treatment are to enhance the movement of the insulator nanoparticles and accelerate the rate of the insulator nanoparticles diffusing into the cavities of the insulating film layer.

[0049] S212, cleaning;

[0050] The epitaxial wafer with the insulating film layer after the heating and ultrasonic oscillation treatment is cleaned. First, the surface of the epitaxial wafer with the insulating film layer is washed with acetone or isopropyl alcohol. The organic solvent such as acetone or isopropyl alcohol can remove the excess insulator nanoparticles on the surface of the epitaxial wafer with the insulating film layer without damaging the insulating film layer. Then, the epitaxial wafer with the insulating film layer is placed in deionized water at 60-90°C for ultrasonic cleaning for 30-60 min. The frequency of the ultrasonic cleaning is 10-30 MHz. If the temperature of the deionized water is too low or the ultrasonic cleaning time is too short, it is relatively difficult to completely remove the acetone or isopropyl alcohol. If the temperature of the deionized water is too high or the ultrasonic cleaning time is too long, other film layers are easily damaged and deteriorated.

[0051] S213, high-temperature annealing treatment in a N2 atmosphere;

[0052] The epitaxial wafer with the insulating film layer after cleaning is subjected to high-temperature annealing treatment in a N2 atmosphere. The N2 atmosphere is to isolate air and protect the epitaxial wafer with the insulating film layer from oxidation during the high-temperature annealing treatment. The flow rate of N2 is 10-100 sccm, and the gas pressure of N2 is 0.01-0.1 mtorr. If the flow rate of N2 is too small or the gas pressure of N2 is too low, the oxygen concentration in the high-temperature annealing treatment environment is relatively high, which causes the oxidation and deterioration of the film layer. If the flow rate of N2 is too large or the gas pressure of N2 is too high, the vacuum valve of the equipment is not easy to control, which causes unstable process.

[0053] The epitaxial wafer with the insulating film layer is placed in a temperature condition of 200-300℃ for 10-30min and then cooled to room temperature. In this process, the insulator nanoparticles further diffuse and embed into the voids in the insulating film layer, and the insulator nanoparticles also combine with the recrystallization of the insulating film layer, so that the density of the insulating film layer is enhanced and the stress is reduced. If the annealing temperature is too high and the holding time is too long, other film layers will be damaged and deteriorated. If the annealing temperature is too low and the holding time is too short, the effect of the insulator nanoparticles diffusing and embedding into the voids in the insulating film layer is poor, and the void rate is still high.

[0054] The insulating film layer is immersed in the corresponding insulator nanoparticle fluid and heated and ultrasonically oscillated, so that the insulator nanoparticles fully embed into the voids in the insulating film layer. Then, high-temperature annealing treatment is performed to make the insulator nanoparticles combine with the recrystallization of the insulating film layer, fill the voids in the insulating film layer, enhance the density of the insulating film layer, and reduce the stress in the insulating film layer. Finally, the leakage rate of the LED chip product is reduced, and the manufacturing yield of the LED chip product is improved.

[0055] S221, a single alloy material ingot is used as a single material source to perform evaporation to form a metal film layer, or multiple metal single-element material ingots are used as multiple material sources to simultaneously perform evaporation to form a metal film layer.

[0056] In the process of manufacturing each layer of metal film layer, a single alloy material ingot can be used as a single material source to perform evaporation deposition to form each layer of metal film layer. The alloy material ingot includes an aluminum-copper material ingot, a nickel-copper material ingot, a titanium-nickel material ingot, or a titanium-platinum material ingot. The alloy material ingot is formed by uniformly mixing metal single-element particles with a particle size of 1-10nm and then pressure casting. The melting points of different types of metal single-element particles differ by no more than 500℃.

[0057] Or multiple metal single-element material ingots can be used as multiple material sources to simultaneously perform evaporation to form each layer of metal film layer. The metal single-element material ingot includes an aluminum ingot, a copper ingot, a nickel ingot, a titanium ingot, or a platinum ingot.

[0058] Different types of metal single-element particles are uniformly mixed and pressure cast to form a specific alloy material ingot as a single material source for evaporation, or each metal single-element material ingot is separately placed in a respective evaporation source, and then multiple material sources simultaneously perform evaporation to form a metal film layer composed of multiple metal elements embedded with each other. These metal elements adhere to each other well without cracks, which reduces the stress in the metal film layer and also significantly reduces the void rate of the metal film layer, thereby improving the reliability of the product.

[0059] The multiple metal single-element material ingots are used as multiple material sources to evaporate simultaneously, so that the content, particle size, thickness and the like of multiple materials can be accurately controlled, but the process requirement is extremely high, a special machine is required to realize the process, the manufacturing cost is extremely high, and the process adaptability is low; the specific alloy material ingot in the form of powder metallurgy is used as a single material source to evaporate, the manufacturing cost is low, the current process requirement is met, and the process adaptability is high.

[0060] Embodiment three:

[0061] The silicon dioxide film layer and the aluminum copper film layer are formed on the epitaxial wafer according to the LED chip process flow.

[0062] After the silicon dioxide film layer is formed, the silicon dioxide film layer is immersed in a silicon dioxide nanoparticle fluid together with the epitaxial wafer for heating and ultrasonic oscillation treatment.

[0063] The silicon dioxide nanoparticle fluid is formed by dispersing silicon dioxide nanoparticles in isopropyl alcohol; the particle size of the silicon dioxide nanoparticles is 1-10 nm.

[0064] The heating temperature is 40-50°C, the heating is performed by water bath, and the treatment time is 30 min; the ultrasonic oscillation treatment is performed at the same time, and the frequency of the ultrasonic oscillation is 30 MHz.

[0065] The epitaxial wafer with the silicon dioxide film layer after the heating and ultrasonic oscillation treatment is cleaned, the surface of the epitaxial wafer with the silicon dioxide film layer is first washed with isopropyl alcohol, and then the epitaxial wafer with the silicon dioxide film layer is placed in deionized water at 80-90°C for ultrasonic cleaning for 50 min, and the frequency of the ultrasonic cleaning is 15 MHz.

[0066] The epitaxial wafer with the silicon dioxide film layer after the cleaning is placed in an N2 atmosphere for high-temperature annealing treatment, the flow rate of the N2 is 10-100 sccm, and the gas pressure of the N2 is 0.01-0.1 mtorr; the high-temperature annealing treatment is performed by placing the epitaxial wafer with the silicon dioxide film layer after the cleaning in a temperature condition of 200-210°C for 30 min and then cooling to room temperature.

[0067] The silicon dioxide film layer is immersed in the silicon dioxide nanoparticle fluid for heating and ultrasonic oscillation, so that the silicon dioxide nanoparticles are fully embedded in the cavities in the silicon dioxide film layer, and then the high-temperature annealing treatment is performed, so that the silicon dioxide nanoparticles and the silicon dioxide film layer are recrystallized and tightly combined, the cavities in the silicon dioxide film layer are filled, the compactness of the silicon dioxide film layer is enhanced, the stress in the silicon dioxide film layer is reduced, the leakage rate of the LED chip product is finally reduced, and the manufacturing yield of the LED chip product is improved.

[0068] In the process of making the aluminum-copper film layer, a single aluminum-copper material ingot is used as a single material source for evaporation deposition to form the aluminum-copper film layer; the aluminum-copper material ingot is formed by pressure casting after uniformly mixing aluminum and copper single-element particles with a particle size of 1-10 nm, and the melting point difference between the two kinds of metal single-element particles is 423℃; the formed aluminum-copper film layer is formed by embedding aluminum elements and copper elements into each other, and the aluminum elements and copper elements adhere to each other well without cracks, thereby reducing the stress in the aluminum-copper film layer and greatly reducing the porosity of the aluminum-copper film layer, and improving the reliability of the product.

[0069] Embodiment Four

[0070] The silicon dioxide-silicon nitride combined film layer and the titanium-nickel film layer are made on the epitaxial wafer according to the LED chip process flow.

[0071] After the formation of the silicon dioxide-silicon nitride combined film layer, the silicon dioxide-silicon nitride combined film layer is immersed together with the epitaxial wafer into a silicon dioxide-silicon nitride combined nanoparticle fluid for heating and ultrasonic oscillation treatment.

[0072] The silicon dioxide-silicon nitride combined nanoparticle fluid is formed by dispersing silicon dioxide nanoparticles and silicon nitride nanoparticles in acetone; the particle size of the silicon dioxide nanoparticles and the silicon nitride nanoparticles is 1-10 nm.

[0073] The heating temperature is 340-350℃, and an electric heating jacket is used for heating, and the treatment time is 10 min; after the heating treatment, ultrasonic oscillation treatment is performed, the frequency of the ultrasonic oscillation is 20 MHz, and the treatment time of the ultrasonic oscillation is 20 min.

[0074] The epitaxial wafer with the silicon dioxide-silicon nitride combined film layer after the heating and ultrasonic oscillation treatment is cleaned, the surface of the epitaxial wafer with the silicon dioxide-silicon nitride combined film layer is first washed with acetone, and then the epitaxial wafer with the silicon dioxide-silicon nitride combined film layer is placed in deionized water at 60-70℃ for ultrasonic cleaning for 40 min, and the frequency of the ultrasonic cleaning is 25 MHz.

[0075] The epitaxial wafer with the silicon dioxide-silicon nitride combined film layer after cleaning is placed in an N2 atmosphere for high-temperature annealing treatment, the flow rate of the N2 is 10-100 sccm, and the gas pressure of the N2 is 0.01-0.1 mtorr; in the high-temperature annealing treatment, the epitaxial wafer with the silicon dioxide-silicon nitride combined film layer after cleaning is placed at a temperature of 290-300℃ for 10 min and then cooled to room temperature.

[0076] The silicon dioxide-silicon nitride combined film layer is immersed in the silicon dioxide-silicon nitride combined nanoparticle fluid and heated and ultrasonically vibrated, so that the silicon dioxide nanoparticles and the silicon nitride nanoparticles are fully embedded in the cavities in the silicon dioxide-silicon nitride combined film layer, and then high-temperature annealing treatment is performed, so that the silicon dioxide nanoparticles, the silicon nitride nanoparticles and the silicon dioxide-silicon nitride combined film layer are recrystallized and closely combined, the cavities in the silicon dioxide-silicon nitride combined film layer are filled, the compactness of the silicon dioxide-silicon nitride combined film layer is enhanced, the stress in the silicon dioxide-silicon nitride combined film layer is reduced, and finally the leakage rate of the LED chip product is reduced and the manufacturing yield of the LED chip product is improved.

[0077] In the process of manufacturing the titanium-nickel film layer, multiple titanium ingots and multiple nickel ingots are used as multiple material sources to simultaneously perform evaporation to form the titanium-nickel film layer; the melting points of the titanium ingots and the nickel ingots differ by 215 DEG C; the titanium-nickel film layer is formed by titanium elements and nickel elements embedded in each other, the titanium elements and the nickel elements are well adhered to each other, there is no crack, the stress in the titanium-nickel film layer is reduced, and the cavity rate of the titanium-nickel film layer is greatly reduced, thereby improving the reliability of the product.

[0078] In summary, the method of the present application immerses the insulating film layer in the corresponding insulator nanoparticle fluid, heats and ultrasonically vibrates, so that the insulator nanoparticles are fully embedded in the cavities in the insulating film layer, and then high-temperature annealing treatment is performed, so that the insulator nanoparticles and the insulating film layer are recrystallized and closely combined, the cavities in the insulating film layer are filled, the compactness of the insulating film layer is enhanced, the stress in the insulating film layer is reduced, and finally the leakage rate of the LED chip product is reduced and the manufacturing yield of the LED chip product is improved.

[0079] By using a special PVD process, different kinds of metal element particles are fully and uniformly mixed and die-cast to form a specific alloy material ingot as a single material source for evaporation, or each metal element material ingot is loaded into a respective evaporation source, and then multiple material sources are simultaneously evaporated to form a metal film layer by embedding a plurality of metal elements in each other, the metal elements are well adhered to each other, there is no crack, the stress in the metal film layer is reduced, and the cavity rate of the metal film layer is greatly reduced, thereby improving the reliability of the product.

[0080] Generally, the cavity rate of the insulating film layer and the metal film layer is determined by the migration concentration and the migration rate of particles passing through the cavities, the cavity rate of the low-cavity-rate LED chip manufactured by the method of the present application is reduced by 30-50% compared with the LED chip before improvement, and the reliability qualified time of the low-cavity-rate LED chip under harsh conditions of high temperature and high humidity is extended to 2016 hours, which is doubled.

[0081] The above has carried out the detailed introduction to the manufacturing method of the low-cavity LED chip provided by the embodiment of the application, the principle and implementation mode of the application are described by adopting specific examples in this paper, the above embodiment description is only used for helping understanding the method of the application and its core idea; meanwhile, for the general technical personnel in the art, according to the idea of the application, the specific implementation mode and application range will have the change, and the above is described, the content of the specification should not be understood as the limitation of the application.

Claims

1. A method for fabricating a low void fraction LED chip, comprising: The method comprises the following steps: ​ 1) forming insulating film layers and metal film layers on an epitaxial wafer according to the process flow of LED chips; 2) after the formation of each insulating film layer, immersing the corresponding insulating film layer and the epitaxial wafer in an insulator nanoparticle fluid for heating and ultrasonic oscillation treatment, so that the insulator nanoparticles in the insulator nanoparticle fluid are fully embedded in the cavities in the insulating film layer; the insulator nanoparticle fluid is formed by dispersing insulator nanoparticles in isopropyl alcohol or acetone; the insulator nanoparticles are a combination of one or more of silicon dioxide nanoparticles, silicon nitride nanoparticles and silicon carbide nanoparticles; cleaning the epitaxial wafer with the insulating film layers after the heating and ultrasonic oscillation treatment, and performing high-temperature annealing treatment in a N2 atmosphere, so that the insulator nanoparticles and the insulating film layers recrystallize and tightly combine, and fill the cavities in the insulating film layers; 3) during the formation of each metal film layer, using a single alloy material ingot as a single material source for evaporation deposition to form the metal film layer; the alloy material ingot is formed by uniformly mixing metal elemental particles and then pressure casting, and the melting points of different types of metal elemental particles differ by no more than 500°C; or using multiple metal elemental material ingots as multiple material sources for simultaneous evaporation to form the metal film layer.

2. The method of claim 1, wherein the LED chip has a low void ratio. The insulating film layer is a combination of one or more of a silicon dioxide film layer, a silicon nitride film layer and a silicon carbide film layer.

3. The method of claim 1, wherein the method further comprises: The particle size of the insulator nanoparticles is 1-10 nm.

4. The method of claim 1, wherein the method further comprises: The heating temperature is 40-350°C, and the heating treatment time is 10-30 min; the ultrasonic oscillation frequency is 10-30 MHz, and the ultrasonic oscillation treatment time is 10-30 min.

5. The method of claim 1, wherein the method further comprises: The cleaning of the epitaxial wafer with the insulating film layers after the heating and ultrasonic oscillation treatment comprises: first, rinsing the surface of the epitaxial wafer with the insulating film layers with acetone or isopropyl alcohol, and then placing the epitaxial wafer with the insulating film layers in deionized water at 60-90°C for ultrasonic cleaning for 30-60 min, and the ultrasonic cleaning frequency is 10-30 MHz.

6. The method of claim 1, wherein the low void fraction LED chip is formed by: The N2 flow rate is 10-100 sccm, and the N2 gas pressure is 0.01-0.1 mtorr.

7. The method of claim 1, wherein the method further comprises: The high-temperature annealing treatment comprises: placing the cleaned epitaxial wafer with the insulating film layers in a temperature condition of 200-300°C for 10-30 min, and then cooling to room temperature.

8. The method of claim 1, wherein the low void fraction LED chip is formed by: The alloy material ingot comprises an aluminum-copper material ingot, a nickel-copper material ingot, a titanium-nickel material ingot or a titanium-platinum material ingot.

9. The method of claim 1, wherein the low void fraction LED chip is formed by: The alloy material ingot is formed by uniformly mixing metal elemental particles with a particle size of 1-10 nm and then pressure casting.

10. The method of claim 1, wherein the method further comprises: forming a plurality of LED chips on the substrate; and forming a plurality of trenches in the substrate, wherein the plurality of trenches are formed to be substantially parallel to each other and substantially perpendicular to the plurality of LED chips. The metal elemental material ingot comprises an aluminum ingot, a copper ingot, a nickel ingot, a titanium ingot or a platinum ingot.

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