Flip chip LED and method for manufacturing the same

Abstract

The application discloses a flip LED chip and a preparation method thereof, and relates to the technical field of semiconductors. The passivation layer comprises a first sub-passivation layer and a second sub-passivation layer, and the metal adhesion layer comprises a first sub-metal adhesion layer and a second sub-metal adhesion layer. The first sub-metal adhesion layer is arranged on the first sub-passivation layer, the reflective layer is arranged on the first sub-metal adhesion layer, the second sub-metal adhesion layer is arranged on the reflective layer, and the second sub-passivation layer is arranged on the second sub-metal adhesion layer. The metal adhesion layer is arranged between the passivation layer and the reflective layer, the adhesion strength between the passivation layer and the reflective layer is enhanced, a gap is avoided, and the blistering rate of the flip LED chip product in the die bonding reflow soldering process is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a flip LED chip and a preparation method thereof. BACKGROUND

[0002] In the flip LED chip product, a plurality of high and low refractive index film layers are alternately deposited on the front surface of the LED chip as a reflection structure, so as to reflect the light emitted from the MQW multi-quantum well layer on the side away from the substrate to the substrate, which has the advantages of high brightness, large light emitting angle and low cost; however, in the process of die bonding and reflow soldering, the adhesion between the reflection structure and the silicon oxide interface is poor, and gaps are prone to occur, which are prone to thermal expansion, resulting in bubbling on the surface of the LED chip product, and further leading to failure of the LED chip. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art, and provides a flip LED chip and a preparation method thereof, which sets a metal adhesion layer between the passivation layer and the reflection layer, enhances the adhesion strength between the passivation layer and the reflection layer, avoids the occurrence of gaps, and reduces the bubbling rate of the flip LED chip product in the process of die bonding and reflow soldering.

[0004] The present application provides a flip LED chip, which comprises a passivation layer, a reflection layer and a metal adhesion layer, wherein:

[0005] The passivation layer comprises a first sub-passivation layer and a second sub-passivation layer, and the metal adhesion layer comprises a first sub-metal adhesion layer and a second sub-metal adhesion layer.

[0006] The first sub-metal adhesion layer is arranged on the first sub-passivation layer, the reflection layer is arranged on the first sub-metal adhesion layer, the second sub-metal adhesion layer is arranged on the reflection layer, and the second sub-passivation layer is arranged on the second sub-metal adhesion layer.

[0007] Specifically, the reflection layer is formed by cyclically laminating any two film layers selected from the group consisting of a SiO2 layer, a Ti3O5 layer, an Al2O3 layer, a TaO2 layer and a Nb2O5 layer.

[0008] Specifically, the reflection layer comprises 30-50 sub-reflection layers, and the optical thickness of any sub-reflection layer is L, wherein λ is one fourth of the central wavelength of the light emitted by the flip LED chip light emitting structure, and the relationship between L and λ is L=(2k+1)*λ, k∈N.

[0009] Specifically, the thickness of the first sub-passivation layer and the second sub-passivation layer is 0.5-1.5 nm.

[0010] Specifically, the thickness of the first sub-metal adhesion layer and the second sub-metal adhesion layer is 0.1-1.0 μm.

[0011] Specifically, the first sub-metal adhesion layer and the second sub-metal adhesion layer are one or more of Ti metal layer, Ni metal layer and Cr metal layer.

[0012] The application further provides a preparation method of the flip LED chip, comprising the following steps:

[0013] The substrate wafer source to be deposited with a passivation layer is subjected to a first water flushing treatment;

[0014] A first sub-passivation layer is deposited on the substrate wafer source after the first water flushing treatment;

[0015] The first sub-passivation layer is subjected to a second water flushing treatment;

[0016] A first sub-metal adhesion layer is evaporated on the first sub-passivation layer after the second water flushing treatment;

[0017] The first sub-metal adhesion layer is subjected to a third water flushing treatment;

[0018] The first sub-metal adhesion layer after the third water flushing treatment is subjected to ion source cleaning;

[0019] A reflective layer is deposited on the first sub-metal adhesion layer after the ion source cleaning;

[0020] The reflective layer is subjected to a fourth water flushing treatment;

[0021] A second sub-metal adhesion layer is evaporated on the reflective layer after the fourth water flushing treatment;

[0022] The second sub-metal adhesion layer is subjected to a fifth water flushing treatment;

[0023] A second sub-passivation layer is deposited on the second sub-metal adhesion layer after the fifth water flushing treatment.

[0024] Specifically, the first water flushing treatment, the second water flushing treatment, the third water flushing treatment, the fourth water flushing treatment and the fifth water flushing treatment each comprise the following steps:

[0025] Spraying, the substrate wafer source to be deposited with a film layer is put into a water flushing tank, and deionized water is sprayed to the substrate wafer source to be deposited with a film layer until the water flushing tank is filled;

[0026] Overflow and bubbling, the deionized water in the water flushing tank is overflowed for 30-60 s, and nitrogen gas is introduced into the water flushing tank for bubbling;

[0027] draining, after the overflow and the bubbling, draining the deionized water in the flushing tank;

[0028] The spraying, the overflowing, the bubbling and the draining are circularly performed 3-6 times.

[0029] Specifically, the depositing the first sub-passivation layer and the depositing the second sub-passivation layer both include:

[0030] In the PECVD, the first sub-passivation layer or the second sub-passivation layer is deposited at a temperature of 280-320 DEG C, a pressure of 90-120 Pa, a power of 90-150 W, a silane gas flow of 10-30 sccm and a dinitrogen monoxide gas flow of 1000-1500 sccm.

[0031] The evaporating the first sub-metal adhesion layer and the evaporating the second sub-metal adhesion layer both include:

[0032] In the electron beam evaporation machine, the first sub-metal adhesion layer or the second sub-metal adhesion layer is evaporated at a vacuum degree of 10 -6 ~ 5 * 10 -5 Pa, An evaporation rate of 10

[0033] The depositing the reflection layer includes:

[0034] In the ion source assisted electron beam evaporation equipment, the reflection layer is deposited at an ion gun voltage of 900-1300 V, an ion gun current of 900-1300 mA, an oxygen flow of 50-100 sccm and an argon flow of 5-15 sccm.

[0035] Specifically, the ion source cleaning includes:

[0036] In the ion source assisted electron beam evaporation equipment, the first sub-metal adhesion layer is cleaned for 60-100 s at an ion gun voltage of 600-800 V, an ion gun current of 500-800 mA, an oxygen flow of 60-80 sccm and an argon flow of 5-10 sccm.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] By arranging the metal adhesion layers, i.e. the first sub-metal adhesion layer and the second sub-metal adhesion layer, to sandwich the reflection layer to form a sandwich structure, and then sandwiching the sandwich structure by the first sub-passivation layer and the second sub-passivation layer to form a composite sandwich structure, the adhesion strength between the passivation layer and the reflection layer is enhanced, the gap is avoided and the bubbling rate of the flip chip LED product in the die bonding reflow soldering process is reduced.

[0039] The dust or particles on the surface of the film layer are removed by water flushing treatment, and then the corresponding film layer is prepared, so that the dust or particles can not affect the tightness between the film layers, the number of gaps is reduced, and the bubbling rate of the flip LED chip product in the die bonding reflow soldering process is reduced.

[0040] The attachments on the surface of the film layer are removed by ion source cleaning, a good interface environment is provided for deposition of the reflection layer, the reflection layer can be tightly combined to the first sub-metal adhesion layer, the gap is not easy to be generated, and the bubbling rate of the flip LED chip product in the die bonding reflow soldering process is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0042] Figure 1 FIG. 1 is a structural schematic diagram of a flip LED chip in an embodiment of the present application;

[0043] Figure 2 FIG. 2 is an enlarged schematic diagram of the a region in FIG. 1; Figure 1

[0044] Figure 3 FIG. 3 is a flow chart of a preparation method of a flip LED chip in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0046] Embodiment one:

[0047] Figure 1 ​The structure diagram of the flip LED chip in the embodiment of the present application is shown, which comprises a patterned substrate 100, and N-GaN layer 210, quantum well layer 220, P-GaN layer 230, current blocking layer 310, current spreading layer 320, electrode layer 400, sidewall protection layer 510, first sub-passivation layer 520, first sub-metal adhesion layer 530, reflective layer 540, second sub-metal adhesion layer 550, second sub-passivation layer 560 and pad layer 600 which are sequentially stacked on the patterned substrate 100; the first sub-passivation layer 520 and the second sub-passivation layer 560 both belong to passivation layers, and the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 both belong to metal adhesion layers.

[0048] Specifically, referring to Figure 2 , the first sub-metal adhesion layer 530 is arranged on the first sub-passivation layer 520, the reflective layer 540 is arranged on the first sub-metal adhesion layer 530, the second sub-metal adhesion layer 550 is arranged on the reflective layer 540, and the second sub-passivation layer 560 is arranged on the second sub-metal adhesion layer 550.

[0049] By arranging the metal adhesion layers, i.e. the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550, between the passivation layers and the reflective layer 540, the reflective layer 540 is sandwiched to form a sandwich structure, and then the first sub-passivation layer 520 and the second sub-passivation layer 560 sandwich the sandwich structure to form a composite sandwich structure, thereby enhancing the adhesion strength between the passivation layers and the reflective layer 540, avoiding the occurrence of gaps, and reducing the bubbling rate of the flip LED chip product in the die bonding reflow soldering process.

[0050] In some specific embodiments, the reflective layer 540 is formed by cyclically stacking any two film layers selected from the group consisting of SiO2 layer, Ti3O5 layer, Al2O3 layer, TaO2 layer and Nb2O5 layer, and the refractive indexes of these film layers are different. By cyclically stacking the film layers with different refractive indexes, the light reflection can be enhanced.

[0051] The refractive index of the SiO2 layer is 1.46, the refractive index of the Ti3O5 layer is 2.35, the refractive index of the Al2O3 layer is 1.63, the refractive index of the TaO2 layer is 2.10, and the refractive index of the Nb2O5 layer is 2.30. Preferably, the SiO2 layer and the Ti3O5 layer are alternately stacked to form the reflective layer 540, or the SiO2 layer and the TaO2 layer are alternately stacked to form the reflective layer 540, or the SiO2 layer and the Nb2O5 layer are alternately stacked to form the reflective layer 540, or the Al2O3 layer and the Ti3O5 layer are alternately stacked to form the reflective layer 540, or the Al2O3 layer and the TaO2 layer are alternately stacked to form the reflective layer 540, or the Al2O3 layer and the Nb2O5 layer are alternately stacked to form the reflective layer 540. The reflective layer 540 formed by alternately stacking the high-refractive-index film layer and the low-refractive-index film layer has a large refractive index difference between the film layers and has a better reflection effect.

[0052] In addition, by arranging the film layers with different refractive indices, the reflection of light of a certain wavelength can be selectively enhanced. When the number of layers is large and the reflection wavelength of the different film layers changes little, such a structure is a Bragg reflector that has a strong reflection effect on a continuous wavelength range.

[0053] Further, the reflective layer 540 includes 30-50 sub-reflection layers 540, and the optical thickness of any sub-reflection layer 540 is L, and λ is one-quarter of the central wavelength of the light emitted by the flip-chip LED chip. The relationship between L and λ is L=(2k+1)*λ, k∈N. The optical thickness is the product of the refractive index and the physical thickness, and N is a natural number. The number of layers of the film layer is large enough, and the optical thickness of the film layer is an odd multiple of λ, which can effectively enhance the reflection effect of the reflective layer 540 on light.

[0054] In some embodiments, the thickness of the first sub-passivation layer 520 and the second sub-passivation layer 560 is 0.5-2 μm. The first sub-passivation layer 520 and the second sub-passivation layer 560 can enhance the passivation effect of the surface of the flip-chip LED chip and prevent the chip from leaking current. The first sub-passivation layer 520 is also an adhesion layer of the reflective layer 540 and the substrate source. If the thickness of the first sub-passivation layer 520 is too small, the adhesion effect of the reflective layer 540 and the substrate source is poor. If the thickness of the first sub-passivation layer 520 is too large, the production capacity is wasted.

[0055] In some embodiments, the thickness of the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 is 0.5-2 μm. The thickness of the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 is appropriate, so that the adhesion effect between the reflection layer 540 and the first sub-passivation layer 520 and the second sub-passivation layer 560 is good; if the thickness of the metal adhesion layer is too thick, the light emitted by the flip LED chip light emitting structure will be absorbed, thereby weakening the brightness of the chip; if the thickness of the metal adhesion layer is too thin, the reflection layer 540 and the passivation layer cannot form good adhesion.

[0056] Further, the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 are one or more of a Ti metal layer, a Ni metal layer, and a Cr metal layer. Ti, Ni, Cr and other metal elements can be covalently bonded with part of the oxygen, achieving good adhesion performance, so that the reflection layer 540 and the passivation layer form good adhesion.

[0057] The present application provides a flip LED chip, by setting a metal adhesion layer between the passivation layer and the reflection layer 540, that is, the first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 sandwich the reflection layer 540 to form a sandwich structure, and then the first sub-passivation layer 520 and the second sub-passivation layer 560 sandwich the sandwich structure to form a composite sandwich structure, thereby enhancing the adhesion strength between the passivation layer and the reflection layer 540, avoiding the occurrence of gaps, and reducing the blistering rate of the flip LED chip product during the die bonding reflow soldering process.

[0058] The film layer with different refractive indexes is arranged in the reflection layer 540 to enhance the reflection of light; the reflection layer 540 formed by the high and low refractive index film layers in a circular stack has better reflection effect; in addition, by arranging the film layers with different refractive indexes, the reflection of light of a certain wavelength can be selectively enhanced; when the number of layers is large and the reflection wavelength between different film layers changes little, such a structure is a Bragg reflector that has strong reflection effect on a continuous wavelength segment; and the number of film layers in the reflection layer 540 is sufficient, and the optical thickness of the film layer is an odd multiple of λ, which can effectively enhance the reflection effect of the reflection layer 540 on light.

[0059] The first sub-passivation layer 520 and the second sub-passivation layer 560 with appropriate thickness can enhance the passivation effect of the surface of the flip LED chip and avoid chip leakage; and can also provide good adhesion effect for the reflection layer 540.

[0060] The first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 with appropriate elements and appropriate thickness have good adhesion effect, so that the reflection layer 540 and the passivation layer are closely attached, the generation of gaps is reduced, and the blistering rate of the flip LED chip product during the die bonding reflow soldering process is reduced.

[0061] Embodiment two:

[0062] Figure 3 A flow chart of the preparation method of the flip LED chip in the embodiment of the application is shown, comprising the following steps:

[0063] S1, performing first water flushing treatment on a substrate wafer source to be deposited with a passivation layer;

[0064] S2, depositing a first sub-passivation layer on the substrate wafer source after the first water flushing treatment;

[0065] S3, performing second water flushing treatment on the first sub-passivation layer;

[0066] S4, evaporating a first sub-metal adhesion layer on the first sub-passivation layer after the second water flushing treatment;

[0067] S5, performing third water flushing treatment on the first sub-metal adhesion layer;

[0068] S6, performing ion source cleaning on the first sub-metal adhesion layer after the third water flushing treatment;

[0069] S7, depositing a reflective layer on the first sub-metal adhesion layer after the ion source cleaning;

[0070] S8, performing fourth water flushing treatment on the reflective layer;

[0071] S9, evaporating a second sub-metal adhesion layer on the reflective layer after the fourth water flushing treatment;

[0072] S10, performing fifth water flushing treatment on the second sub-metal adhesion layer;

[0073] S11, depositing a second sub-passivation layer on the second sub-metal adhesion layer after the fifth water flushing treatment.

[0074] The first sub-metal adhesion layer 530 and the second sub-metal adhesion layer 550 make the reflective layer 540 form good adhesion between the first sub-passivation layer 520 and the second sub-passivation layer 560, avoid the occurrence of gaps, and reduce the blistering rate of the flip LED chip product in the die bonding reflow soldering process;

[0075] The dust or particles on the surface of the film layer are removed by water flushing treatment, and then the corresponding film layer is prepared, which can avoid the influence of the dust or particles on the tightness between the film layers, reduce the number of gaps, and reduce the blistering rate of the flip LED chip product in the die bonding reflow soldering process; and can also prevent the dust or particles from causing defects of the film layer and protect the photoelectric performance of the flip LED chip;

[0076] The adhesion of the reflective layer 540 to the first sub-metal adhesion layer 530 is improved, and the gap between the reflective layer 540 and the first sub-metal adhesion layer 530 is reduced, so that the bubble rate of the flip LED chip product in the die bonding and reflow soldering process is reduced.

[0077] Further, the first water flushing treatment, the second water flushing treatment, the third water flushing treatment, the fourth water flushing treatment and the fifth water flushing treatment each include the following steps:

[0078] Spraying, the substrate film source to be deposited is placed in a water flushing tank, and deionized water is sprayed to the substrate film source to be deposited until the water flushing tank is filled with the deionized water;

[0079] Overflow and bubbling, the deionized water in the water flushing tank is overflowed for 30-60 seconds, and nitrogen gas is introduced into the water flushing tank for bubbling;

[0080] Draining, after the overflow and the bubbling are completed, the deionized water in the water flushing tank is drained;

[0081] The spraying, the overflow, the bubbling and the draining are cyclically performed for 3-6 times.

[0082] The entire water flushing treatment process lasts for 300-600 seconds, and the time for one spraying to draining is about 100 seconds.

[0083] The spraying can flush the film layer to remove dust or particles; the overflow can continuously update the deionized water to remove dust or particles; the nitrogen bubbling can increase the flushing force of the deionized water and reduce the oxygen content in the deionized water; and the draining can remove dust or particles. The purpose of the water flushing treatment is to remove dust or particles on the surface of the film layer, so that the surface of the film layer is kept clean, the generation of defects, gaps and the like between the film layers is reduced, and the bubble rate of the flip LED chip product in the die bonding and reflow soldering process is reduced. The number of cycles and the duration of the water flushing treatment depend on the cleanliness of the surface of the film layer. If the number of cycles and the duration are too small, the dust or particles on the surface of the film layer cannot be cleaned. If the number of cycles and the duration are too large, resources are wasted.

[0084] Further, the deposition of the first sub-passivation layer 520 and the deposition of the second sub-passivation layer 560 each include: in a PECVD, the first sub-passivation layer 520 or the second sub-passivation layer 560 is deposited at a temperature of 280-320℃, a pressure of 90-120 Pa, a power of 90-150 W, a silane gas flow rate of 10-30 sccm and a dinitrogen monoxide gas flow rate of 1000-1500 sccm.

[0085] PECVD is to make the gas containing thin film composition atoms, form plasma in local by microwave or radio frequency, and the plasma chemical activity is very strong, so that the chemical reaction is easy to occur, and the expected thin film is deposited on the substrate source. The appropriate deposition temperature, deposition pressure, deposition power, silane gas flow, nitrous oxide gas flow are beneficial to enhance the passivation effect of the first sub-passivation layer 520 and the second sub-passivation layer 560, and avoid the leakage of flip-chip LED chip.

[0086] If the deposition temperature is too low, the deposition rate of the first sub-passivation layer 520 and the second sub-passivation layer 560 is too slow, and the chemical reaction is insufficient, which will reduce the compactness of the film layer; if the deposition temperature is too high, the active metal in the electrode will migrate, which will cause the leakage failure of the flip-chip LED chip product.

[0087] If the deposition pressure is too low, the chemical reaction is insufficient, which will cause the compactness of the passivation layer formed by deposition to be poor; if the deposition pressure is too high, the chemical reaction rate will be slow, and the by-products generated in the chemical reaction cannot be discharged in time, which will cause the compactness of the passivation layer formed by deposition to be poor.

[0088] If the deposition power is too low, the active reaction molecules cannot be effectively excited, which will cause the deposition rate of the passivation layer to be slow; if the deposition power is too high, the film layer will be damaged, which will affect the photoelectric performance of the flip-chip LED chip product.

[0089] If the silane gas flow is too low, the deposition rate of the passivation layer will be slow; if the silane gas flow is too high, the deposition rate of the passivation layer will be fast, which is not easy to control, and will affect the compactness and uniformity of the film layer.

[0090] If the nitrous oxide gas flow is too low, the deposition rate of the passivation layer will be slow; if the nitrous oxide gas flow is too high, the deposition rate of the passivation layer will be fast, which is not easy to control, and will affect the compactness and uniformity of the film layer.

[0091] Further, the evaporation of the first sub-metal adhesion layer 530 and the evaporation of the second sub-metal adhesion layer 550 each includes: in an electron beam evaporation machine, the first sub-metal adhesion layer 530 or the second sub-metal adhesion layer 550 is evaporated at a vacuum degree of 10 -6 ~ 5 × 10 -5 Pa, and an evaporation rate of 0.5 A / s.

[0092] The electron beam evaporation method is a kind of vacuum evaporation coating method. In the method, the electron beam is used to directly heat and evaporate the material under vacuum condition, so that the evaporated material gasifies and transports to the target area, and then condenses on the target area to form a thin film. Specifically, in the electron beam evaporation machine, the electron beam is used to bombard the metal source material to heat and evaporate it from solid to liquid and then to gas. After the gaseous metal reaches the surface of the substrate, it cools down to form a metal film layer.

[0093] If the vacuum degree is too low, there will be many impurity molecules in the cavity of the electron beam evaporation machine, which will hinder the gaseous metal from reaching the surface of the substrate, resulting in poor compactness of the metal adhesion layer formed by evaporation.

[0094] If the evaporation rate is too slow, the time required for the metal adhesion layer to form by evaporation will be long, and the efficiency will be low. If the evaporation rate is too fast, the thickness of the metal adhesion layer will be difficult to control, affecting the uniformity of the film layer.

[0095] Further, the deposition of the reflective layer 540 includes: in the ion source assisted electron beam evaporation device, the ion gun voltage is 900-1300V, the ion gun current is 900-1300mA, the oxygen flow is 50-100sccm, and the argon flow is 5-15sccm.

[0096] If the ion gun voltage is lower than 900V, the energy of the ion beam formed will be low, which cannot effectively improve the compactness of the reflective layer 540. If the ion gun voltage is higher than 1300V, the energy of the ion beam formed will be too high, which will easily damage the reflective layer 540 and the film layer below it.

[0097] If the ion gun current is lower than 900mA, the number of ions formed per unit area will be insufficient, which will easily lead to a lack of appropriate oxygen ions in the evaporation-condensation process of the reflective layer 540, so that the film layer material lacks oxygen elements, thereby enhancing the light absorption effect of the reflective layer 540. If the ion gun current is higher than 1300mA, there will be too many oxygen ions in the evaporation-condensation process of the reflective layer 540, which will cause the film layer material to form an oxygen-rich structure, thereby causing the reflective layer 540 to be foggy.

[0098] If the oxygen flow is too low, it will easily lead to a lack of appropriate oxygen ions in the evaporation-condensation process of the reflective layer 540, so that the film layer material lacks oxygen elements, thereby enhancing the light absorption effect of the reflective layer 540. If the oxygen flow is too high, there will be too many oxygen ions in the evaporation-condensation process of the reflective layer 540, which will cause the film layer material to form an oxygen-rich structure, thereby causing the reflective layer 540 to be foggy.

[0099] If the argon flow is too low, the ion source is difficult to start; if the argon flow is too high, it will cause bombardment damage to the film layer below the reflection layer 540.

[0100] The reflection layer 540 has a total of 30-50 layers, and the ion source assisted deposition technology helps to improve the density of the internal film layer of the reflection layer 540, reduce the voids in the reflection layer 540, and make the internal film layers of the reflection layer 540 adhere more closely, thereby reducing the bubble rate of the flip chip LED product during the die bonding reflow soldering process.

[0101] Further, the ion source cleaning includes: in the ion source assisted electron beam evaporation equipment, the first sub-metal adhesion layer 530 is cleaned for 60-100s with an ion gun voltage of 600-800V, an ion gun current of 500-800mA, an oxygen flow of 60-80sccm, and an argon flow of 5-10sccm.

[0102] If the ion gun voltage is lower than 600V, the ion beam energy formed is too low to remove the physically or chemically adsorbed substances on the surface of the first sub-metal adhesion layer 530; if the ion gun voltage is higher than 800V, the ion beam energy formed is too high, which is easy to produce ion implantation effect, causing damage to the first sub-metal adhesion layer 530.

[0103] If the ion gun current is lower than 500mA, the number of ions formed per unit area is insufficient to remove the physically or chemically adsorbed substances on the surface of the first sub-metal adhesion layer 530; if the ion gun current is higher than 800mA, the number of ions formed per unit area is too large, and the ions are easy to collide, thereby causing the ions to fail to reach the surface of the first sub-metal adhesion layer 530 or to reach the surface of the first sub-metal adhesion layer 530 with too low energy, weakening the cleaning effect.

[0104] If the oxygen flow is too low, it is difficult to remove the organic matter on the surface of the first sub-metal adhesion layer 530; if the oxygen flow is too high, it will cause bombardment damage to the first sub-metal adhesion layer 530.

[0105] If the argon flow is too low, the ion gun will fail to ignite, and it is difficult to remove the inorganic attachments on the surface of the first sub-metal adhesion layer 530; if the argon flow is too high, it will cause bombardment damage to the first sub-metal adhesion layer 530.

[0106] If the cleaning time is less than 60s, the surface of the first sub-metal adhesion layer 530 cannot be effectively cleaned; if the cleaning time is greater than 100s, the time is too long and the production capacity is wasted.

[0107] The application provides a preparation method of an inverted LED chip.

[0108] The application removes dust or particles on the surface of the film layer through water flushing treatment, keeps the surface of the film layer clean, reduces the generation of defects, gaps and the like between the film layers, reduces the blistering rate of the inverted LED chip product in the die bonding reflow soldering process, prevents the dust or particles from causing film layer defects, and protects the photoelectric performance of the inverted LED chip.

[0109] The application performs ion source cleaning on the first sub-metal adhesion layer 530 before depositing the reflection layer 540, removes the attachments on the surface of the film layer, provides a good interface environment for the deposition of the reflection layer 540, enables the reflection layer 540 to be closely combined to the first sub-metal adhesion layer 530, is not prone to generate gaps, reduces the blistering rate of the inverted LED chip product in the die bonding reflow soldering process, prevents the attachments from causing film layer defects, and protects the photoelectric performance of the inverted LED chip.

[0110] The application forms the reflection layer 540 through ion source assisted deposition technology, which is helpful to improve the compactness of the internal film layer of the reflection layer 540, reduce the cavities in the reflection layer 540, enable the internal film layers of the reflection layer 540 to be more closely combined, reduce the gaps between the film layers, and thus reduce the blistering rate of the inverted LED chip product in the die bonding reflow soldering process.

[0111] The application obtains the inverted LED chip with low blistering rate through the metal adhesion layer, ion source cleaning before the deposition of the reflection layer 540, and ion source assisted deposition of the reflection layer 540, and the blistering rate of the inverted LED chip product in the die bonding reflow soldering process can be reduced to 0%.

[0112] The above provides a detailed introduction to the inverted LED chip and the preparation method thereof provided by the embodiment of the application, and the principle and implementation mode of the application are described by using specific examples in this paper, and the above embodiment description is only used to help understand the method and the core idea of the application; meanwhile, for the general technical personnel in the art, the specific implementation mode and application range can be changed according to the idea of the application, and the above description should not be understood as the limitation of the application.

Claims

1. An inverted LED chip, characterized by, The passivation layer, the reflection layer and the metal adhesion layer, wherein: The passivation layer comprises a first sub-passivation layer and a second sub-passivation layer, and the metal adhesion layer comprises a first sub-metal adhesion layer and a second sub-metal adhesion layer; The first sub-metal adhesion layer is arranged on the first sub-passivation layer, the reflection layer is arranged on the first sub-metal adhesion layer, the second sub-metal adhesion layer is arranged on the reflection layer, and the second sub-passivation layer is arranged on the second sub-metal adhesion layer; The reflection layer is formed by cyclically laminating any two film layers selected from the group consisting of a SiO2 layer, a Ti3O5 layer, an Al2O3 layer, a TaO2 layer and a Nb2O5 layer; The reflection layer comprises 30-50 sub-reflection layers, and the optical thickness of any one of the sub-reflection layers is L, wherein λ is one quarter of the central wavelength of the light emitted by the flip-chip LED chip, and the relationship between L and λ is L=(2k+1)*λ, k∈N; The first sub-metal adhesion layer and the second sub-metal adhesion layer are one or more of a Ti metal layer, a Ni metal layer and a Cr metal layer.

2. The flip-chip LED chip of claim 1, wherein, The thickness of the first sub-passivation layer and the second sub-passivation layer is 2000-3000 Å.

3. The flip-chip LED chip of claim 1, wherein, The thickness of the first sub-metal adhesion layer and the second sub-metal adhesion layer is 10-50 Å.

4. A method of manufacturing the flip-chip LED chip according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: The first water flushing treatment is performed on a substrate wafer to be deposited with a passivation layer; The first sub-passivation layer is deposited on the substrate wafer after the first water flushing treatment; The second water flushing treatment is performed on the first sub-passivation layer; The first sub-metal adhesion layer is evaporated on the first sub-passivation layer after the second water flushing treatment; The third water flushing treatment is performed on the first sub-metal adhesion layer; The ion source cleaning is performed on the first sub-metal adhesion layer after the third water flushing treatment; The reflection layer is deposited on the first sub-metal adhesion layer after the ion source cleaning; The fourth water flushing treatment is performed on the reflection layer; The second sub-metal adhesion layer is evaporated on the reflection layer after the fourth water flushing treatment; The fifth water flushing treatment is performed on the second sub-metal adhesion layer; The second sub-passivation layer is deposited on the second sub-metal adhesion layer after the fifth water flushing treatment; The first water flushing treatment, the second water flushing treatment, the third water flushing treatment, the fourth water flushing treatment and the fifth water flushing treatment each comprise the following steps: Spraying, the substrate wafer to be deposited with a film layer is placed in a water flushing tank, and deionized water is sprayed to the substrate wafer to be deposited with a film layer until the water flushing tank is filled; Overflow and bubbling, the deionized water in the water flushing tank is overflowed for 30-60 s, and nitrogen gas is introduced into the water flushing tank for bubbling; Drainage, after the overflow and the bubbling are completed, the deionized water in the water flushing tank is drained; The spraying, the overflow, the bubbling and the drainage are cyclically performed for 3-6 times.

5. The method of claim 4, wherein, The deposition of the first sub-passivation layer and the deposition of the second sub-passivation layer each comprise: In the PECVD, the first sub-passivation layer or the second sub-passivation layer is deposited at a temperature of 280-320℃, a pressure of 90-120Pa, a power of 90-150W, a silane gas flow rate of 10-30sccm, and a nitrous oxide gas flow rate of 1000-1500sccm; The evaporation first sub-metal adhesion layer and the evaporation second sub-metal adhesion layer each comprise: In the electron beam evaporation machine, the first sub-metal adhesion layer or the second sub-metal adhesion layer is evaporated at a vacuum degree of 10 -6 ~5x10 -5 Pa, and an evaporation rate of 0.1~0.2 Å / S. The deposition reflective layer comprises: In the ion source assisted electron beam evaporation device, the reflective layer is deposited at an ion gun voltage of 900-1300V, an ion gun current of 900-1300mA, an oxygen flow rate of 50-100sccm, and an argon flow rate of 5-15sccm.

6. The method of claim 4, wherein, The ion source cleaning comprises: In the ion source assisted electron beam evaporation device, the first sub-metal adhesion layer is cleaned at an ion gun voltage of 600-800V, an ion gun current of 500-800mA, an oxygen flow rate of 60-80sccm, and an argon flow rate of 5-10sccm for 60-100s.

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