Flip-chip Mini / Micro-LED chips easy to weld, preparation method thereof, and packaging method thereof

Abstract

The present invention discloses an easy-to-weld flip-chip Mini / Micro-LED chip, a preparation method thereof, and a packaging method. The chip includes a substrate, a light-emitting structure disposed on the substrate, an electrode disposed on the light-emitting structure, and a welding layer disposed on the electrode. The Mini / Micro-LED chip of the present invention is easy to be welded and packaged, and has high packaging efficiency, high yield, and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of light-emitting diodes, and particularly to a flip-chip Mini / Micro-LED chip that is easy to weld, and a preparation method and a packaging method thereof. Background Art

[0002] The flip-chip LED chip has the characteristic of being non-encapsulated, thus greatly reducing the wire bonding and soldering time and cost of downstream packaging factories. Although the wire bonding and soldering steps can be omitted, solder and flux still need to be applied to the electrodes to form an electrical connection between the electrodes of the LED chip and the substrate.

[0003] The pads of Mini / Micro-LED chips are smaller, the amount of solder paste is less, and the chips are smaller, which puts higher requirements on process parameters such as the requirements for welding equipment and temperature uniformity. The current problems in welding include: 1. Chip displacement: The chip moves after welding, and the movement of the bare chip after welding needs to be reduced; 2. Chip rotation: Since the pitch of Mini / Micro-LED chips themselves is only 0.8 mm, 0.6 mm, 0.4 mm or even smaller, during the welding process, the chips are prone to rotate in the atmosphere environment, affecting the quality; 3. High void ratio: After welding by nitrogen reflow soldering, using solder paste with a low void ratio, the void ratio after welding can only be controlled to about 10%; for ordinary solder paste, the void ratio after welding may reach more than 15%. A too high void ratio may cause product defects due to heat conduction effects or reliability problems in long-term use. There are more than 9,000 chips on a circuit board, and a few defects leading to the defects of the final product are a very serious matter.

[0004] In addition, the existing methods for applying solder and flux are generally divided into the dot solder paste method and the brush solder paste method. Among them, the dot solder paste method is fast, but has low accuracy, uses a large amount of glue, is easy to overflow, and the chips are prone to displacement and short circuit; the brush solder paste method has high accuracy, but is slow, and the machine price is high. Therefore, the step of brushing solder paste for Mini / Micro-LED chips has a great barrier to the promotion of flip-chip products of Mini / Micro-LED chips. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a flip-chip Mini / Micro-LED chip that is easy to weld, and a preparation method thereof, which is easy to weld and package, and has high packaging efficiency, high yield and low cost.

[0006] The technical problem to be solved by the present invention is also to provide a packaging method for a flip-chip Mini / Micro-LED chip that is easy to weld, and has high packaging efficiency, high yield and low cost.

[0007] To solve the above technical problems, the present invention provides a flip-chip Mini / Micro-LED chip that is easy to weld, including a substrate, a light-emitting structure disposed on the substrate, an electrode disposed on the light-emitting structure, and a solder layer disposed on the electrode;

[0008] The solder layer includes a solder layer, a soldering aid layer disposed on the solder layer, and a protective layer disposed on the solder layer and the soldering aid layer and wrapping the soldering aid layer; wherein,

[0009] The soldering aid layer is made of a soldering aid, the viscosity of the soldering aid is 200-600 kcps, and the residue after reflow soldering is less than 50%;

[0010] The material of the soldering aid layer is selected from one or more of rosin, resin, and halogen-containing compounds;

[0011] The material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax.

[0012] As an improvement of the above solution, the material of the soldering aid layer is selected from rosin and / or resin;

[0013] The resin is a thermosetting resin and is selected from one or more of unsaturated polyester, vinyl ester, epoxy-type maleimide resin, phenolic-type maleimide resin, bismaleimide resin, and polyimide resin.

[0014] As an improvement of the above solution, the thickness of the solder layer is 10-100 μm;

[0015] The thickness of the soldering aid layer is 2-20 μm.

[0016] As an improvement of the above solution, the thickness of the protective layer is 1-10 μm.

[0017] Correspondingly, the present invention also provides a method for manufacturing a flip-chip Mini / Micro-LED chip that is easy to weld, including:

[0018] 1. Form a light-emitting structure on the substrate;

[0019] 2. Form an electrode on the light-emitting structure;

[0020] 3. Form a solder layer on the electrode, and the material of the solder layer is selected from one or more of tin-lead solder, silver solder, copper solder, and pure tin solder;

[0021] 4. Form a soldering aid layer on the solder layer, the soldering aid layer is made of a soldering aid, the viscosity of the soldering aid is 200-600 kcps, and the residue after reflow soldering is less than 50%;

[0022] V. A protective layer is formed on the solder layer and the solder mask layer. The protective layer wraps the solder mask layer, and the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax.

[0023] As an improvement to the above solution, a solder layer is formed on the electrode by means of yellow light evaporation coating or stencil printing, and the thickness of the solder layer is 10 - 100 μm.

[0024] In step (IV), a solder mask layer is formed on the solder layer by means of spin coating or spraying, and the thickness of the solder mask layer is 2 - 20 μm.

[0025] In step (V), a protective layer is formed on the solder mask layer by means of spin coating or spraying, and the thickness of the protective layer is 1 - 10 μm.

[0026] Correspondingly, the present invention also provides a packaging method for flip-chip Mini / Micro-LED chips, including:

[0027] A. Place the above-mentioned flip-chip Mini / Micro-LED chip on the substrate. Among them, the welding layer of the flip-chip Mini / Micro-LED chip is aligned with the pad on the substrate.

[0028] B. Heat the substrate, and the welding layer is bonded between the flip-chip Mini / Micro-LED chip and the substrate, and the solder mask layer and the pad form a carbon-containing compound.

[0029] As an improvement to the above solution, in step (B), the substrate is heated gradiently. Set the first temperature zone, the second temperature zone, the third temperature zone, the fourth temperature zone, the fifth temperature zone, the sixth temperature zone, and the seventh temperature zone. Among them, 150°C < the temperature of the first temperature zone < the temperature of the second temperature zone < the temperature of the third temperature zone < the temperature of the fourth temperature zone < the temperature of the fifth temperature zone < the temperature of the sixth temperature zone < the temperature of the seventh temperature zone < 250°C.

[0030] As an improvement to the above solution, the temperature of the first temperature zone is 160 - 165°C, the temperature of the second temperature zone is 170 - 175°C, the temperature of the third temperature zone is 180 - 185°C, the temperature of the fourth temperature zone is 190 - 195°C, the temperature of the fifth temperature zone is 200 - 205°C, the temperature of the sixth temperature zone is 210 - 215°C, and the temperature of the seventh temperature zone is 220 - 225°C.

[0031] Implementing the present invention has the following beneficial effects:

[0032] In the wafer stage of the LED, the present invention simultaneously forms a solder layer on the electrodes of multiple light-emitting structures. Compared with the encapsulation methods of applying solder paste point by point and brushing solder paste on each LED chip, the efficiency is greatly improved. Moreover, by controlling the thickness of the solder layer, the amount of solder paste can be accurately controlled, avoiding excessive or insufficient use of solder paste, effectively ensuring the bonding force between the chip and the substrate, and preventing the chip from rotating and shifting, thereby improving the soldering yield of the LED chip and the substrate.

[0033] In addition, the soldering aid layer of the present invention is provided on the solder layer to further fill the fine gaps between the electrode and the substrate. After soldering, the void ratio is less than 10%; more importantly, during soldering, the soldering aid layer can form a strong carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two.

[0034] Furthermore, the protective layer of the present invention is provided on the solder layer and the soldering aid layer and wraps the soldering aid layer, which is used to protect the soldering aid layer, prevent dust and impurities from adhering to the soldering aid layer, ensure the performance of the soldering aid layer, and facilitate storage and transportation at the same time.

[0035] The present invention uses the method of gradient zoning heating to fully melt the soldering layer and the soldering aid layer, perfectly bond them between the electrode and the substrate, effectively prevent solder overflow, and fully fill the fine gaps between the electrode and the substrate, further improving the bonding strength between the electrode and the substrate. After soldering, the void ratio is less than 10%; in addition, through gradient heating, the soldering aid layer can form more strong carbon-containing compounds with the metal on the substrate, further improving the bonding strength between the two.

[0036] The encapsulation method of the present invention saves equipment such as solder paste brushing machines and dispensing machines, simplifies the entire encapsulation production process, effectively shortens the encapsulation time, and greatly reduces costs. Description of the Drawings

[0037] Figure 1 is a schematic structural diagram of the flip-chip Mini / Micro-LED chip of the present invention. Detailed Embodiments

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] See Figure 1 , a flip-chip Mini / Micro-LED chip that is easy to solder provided by the present invention includes a substrate 10, a light-emitting structure 20 provided on the substrate 10, an electrode 30 provided on the light-emitting structure 20, and a soldering layer 40 provided on the electrode 30. Among them, the size of the flip-chip Mini / Micro-LED chip is less than 100 μm.

[0040] The welding layer 40 includes a solder layer 41, a soldering aid layer 42 disposed on the solder layer 41, and a protective layer 43 disposed on the solder layer 41 and the soldering aid layer 42 and wrapping the soldering aid layer 42.

[0041] The solder layer of the present invention is used to bond the electrode and the substrate. Therefore, the material of the solder layer must be a conductive material. In addition, in order to improve the bonding force between the electrode and the substrate, the solder layer is also used to fill the gap between the electrode and the substrate, reduce the unevenness between the chip and the substrate, reduce the void ratio between the chip and the substrate, and increase the reliability of the welding layer. Therefore, the material of the solder layer must have a certain softness. Preferably, the material of the solder layer is selected from one or more of tin-lead solder, silver solder, copper solder, and pure tin solder.

[0042] Among them, the thickness of the solder layer plays an important role in the subsequent welding and packaging of the chip. If the thickness of the solder layer is too thick, it is easy to overflow during welding, resulting in chip leakage. If the thickness of the solder layer is too small, the chip and the substrate are not firmly bonded, reducing the welding yield.

[0043] Preferably, the thickness of the solder layer is 10-100 μm. More preferably, the thickness of the solder layer is 20-80 μm. Most preferably, the thickness of the solder layer is 40-60 μm.

[0044] Specifically, the present invention forms a solder layer on the electrode by means of yellow light evaporation or stencil printing. In the wafer stage of the LED, the present invention simultaneously forms a solder layer on the electrodes of multiple light-emitting structures. Compared with the packaging method of individually applying solder paste and brushing solder paste to each LED chip, the efficiency is greatly improved, and the amount of solder paste can be accurately controlled by controlling the thickness of the solder layer, avoiding too much or too little solder paste, effectively ensuring the bonding force between the chip and the substrate, and preventing the chip from rotating and shifting, thereby improving the welding yield of the LED chip and the substrate.

[0045] The existing welding method for flip-chip LED chips is to mix solder and flux to form solder paste, then apply the solder paste on the pads of the substrate, then weld the flip-chip LED chips, and finally perform reflow soldering. Since the solder and flux are mixed together in the existing method, during the reflow soldering process, a long-time heat preservation is required to volatilize the flux in the solder paste completely to remove the oxides on the pads and the chip electrodes.

[0046] The present invention separates the solder and the flux to form a solder layer and a soldering aid layer. Among them, the soldering aid layer of the present invention is disposed on the solder layer, which can fill the fine gaps between the electrode and the substrate, and the void ratio after welding is less than 10%. More importantly, during welding, the soldering aid layer can form a strong carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two.

[0047] In addition, the solder layer and the soldering flux layer of the present invention are separated. During reflow soldering, the soldering flux layer can melt prior to the solder layer, form a firm carbon-containing compound with the metal on the substrate, and fully fill the minute gaps between the electrodes and the substrate. Since the present invention can adjust the thickness of the soldering flux layer through the process to control the amount of soldering flux used, the holding time during the reflow soldering process can be shortened.

[0048] Specifically, the soldering flux layer of the present invention is made of a soldering flux, and the viscosity of the soldering flux is 200 - 600 kcps, and the residue after reflow soldering is less than 50%.

[0049] Among them, the viscosity of the soldering flux plays an important role in the soldering of the chip. If the viscosity of the soldering flux is too low, it is difficult to form on the solder layer, and the thickness is difficult to control, and it is also easy to overflow during reflow soldering; if the viscosity of the soldering flux is too high, it is difficult to fully fill the minute gaps between the electrodes and the substrate during reflow soldering.

[0050] Theoretically, the smaller the residue of the soldering flux after reflow soldering, the better. Since the soldering flux of the present invention has been formed at the chip stage and its thickness can be controlled, the residue of the soldering flux of the present invention after reflow soldering only needs to be less than 50%.

[0051] Preferably, the viscosity of the soldering flux is 300 - 500 kcps, and the residue after reflow soldering is less than 40%.

[0052] More preferably, the viscosity of the soldering flux is 400 - 450 kcps, and the residue after reflow soldering is less than 40%.

[0053] Among them, the material of the soldering flux layer is selected from rosin and / or resin.

[0054] The resin is a thermosetting resin, selected from one or more of unsaturated polyester, vinyl ester, epoxy-type maleimide resin, phenolic-type maleimide resin, bismaleimide resin, and polyimide resin. The above resins can be quickly hardened by heat and are easy to volatilize, and become electrically conductive carbon atoms at high temperature, effectively filling the minute gaps between the electrodes and the substrate. The above materials can be formed by spin coating or spraying, and the manufacturing method is simple.

[0055] Preferably, the rosin contains 1% - 5% by mass of a halogen compound. Adding a certain amount of halogen compound to the rosin in the present invention can make the soldering flux form a more firm carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two. Among them, the halogen compound is a compound containing one or more elements of fluorine, chlorine, bromine, iodine, and astatine. Since the halogen itself has high activity, the reaction can be accelerated.

[0056] Among them, the thickness of the solder mask layer plays an important role in the subsequent packaging and soldering of the chip. If the thickness of the solder mask layer is too thick, it is likely to overflow during soldering, resulting in chip leakage. If the thickness of the solder mask layer is too small, the chip and the substrate will not be firmly bonded, reducing the soldering yield.

[0057] Preferably, the thickness of the solder mask layer is 2 - 20 μm. More preferably, the thickness of the solder mask layer is 5 - 15 μm. Most preferably, the thickness of the solder mask layer is 8 - 15 μm.

[0058] Since the solder mask layer has a certain viscosity, in order to avoid adhering some impurities on the solder mask layer and affecting the performance of the solder mask layer, the protective layer of the present invention is provided on the solder layer and the solder mask layer and wraps the solder mask layer for easy storage and transportation.

[0059] Preferably, the material of the protective layer is selected from one of polyethylene, ethylene - tetrafluoroethylene, and wax. The above materials can be formed by spin coating or spraying. The manufacturing method is simple, effectively protects the solder mask layer, and will not affect the solder mask layer and soldering. Specifically, the above materials will instantly shrink into a small molecular state at high temperature and do not affect soldering.

[0060] Among them, the thickness of the protective layer is 1 - 10 μm. Preferably, the thickness of the protective layer is 3 - 7 μm. More preferably, the thickness of the protective layer is 4 - 6 μm.

[0061] Correspondingly, the present invention also provides a method for manufacturing a flip - chip Mini / Micro - LED chip that is easy to solder, including the following steps:

[0062] 1. Form a light - emitting structure on the substrate;

[0063] Specifically, a plurality of light - emitting structures are provided on the substrate.

[0064] 2. Form electrodes on the light - emitting structure;

[0065] Among them, electrodes are provided on each light - emitting structure. The electrodes include a positive electrode and a negative electrode. The electrodes can be existing electrode structures, and the present invention does not make specific limitations.

[0066] 3. Form a solder layer on the electrodes;

[0067] The solder layer of the present invention is used to bond the electrodes and the substrate. Therefore, the material of the solder layer must be a conductive material. In addition, in order to improve the bonding force between the electrodes and the substrate, the solder layer is also used to fill the gaps between the electrodes and the substrate, reduce the unevenness between the chip and the substrate, reduce the void ratio between the chip and the substrate, and increase the reliability of the solder layer. Therefore, the material of the solder layer must have a certain softness. Preferably, the material of the solder layer is selected from one or several of tin - lead solder, silver solder, copper solder, and pure tin solder.

[0068] Among them, the thickness of the solder layer plays an important role in the subsequent packaging and soldering of the chip. If the thickness of the solder layer is too thick, it is easy to overflow during soldering, resulting in chip leakage; if the thickness of the solder layer is too small, the chip and the substrate are not firmly combined, reducing the soldering yield.

[0069] Preferably, the thickness of the solder layer is 10 - 100 μm. More preferably, the thickness of the solder layer is 20 - 80 μm. Most preferably, the thickness of the solder layer is 40 - 60 μm.

[0070] Specifically, the present invention forms a solder layer on the electrode by means of yellow light evaporation or stencil printing. In the wafer stage of the LED, the present invention simultaneously forms a solder layer on the electrodes of multiple light-emitting structures. Compared with the packaging method of applying solder paste and brushing solder paste to each LED chip one by one, the efficiency is greatly improved, and the amount of solder paste can be accurately controlled by controlling the thickness of the solder layer, avoiding too much or too little solder paste, effectively ensuring the bonding force between the chip and the substrate, and preventing the chip from rotating and shifting, thereby improving the soldering yield of the LED chip and the substrate.

[0071] IV. Form a soldering aid layer on the solder layer;

[0072] The soldering aid layer of the present invention is provided on the solder layer to further fill the fine gaps between the electrode and the substrate. More importantly, during soldering, the soldering aid layer can form a strong carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two.

[0073] The existing soldering method for flip-chip LED chips is to mix solder and soldering flux to form solder paste, then apply it on the solder pads of the substrate, then solder the flip-chip LED chips, and finally perform reflow soldering. Since the solder and the soldering flux are mixed together in the existing method, during the reflow soldering process, a long-time heat preservation is required to volatilize the soldering flux in the solder paste completely to remove the oxides on the solder pads and the chip electrodes.

[0074] The present invention separates the solder and the soldering flux to form a solder layer and a soldering aid layer. Among them, the soldering aid layer of the present invention is provided on the solder layer, which can fill the fine gaps between the electrode and the substrate, and the void ratio after soldering is less than 10%; more importantly, during soldering, the soldering aid layer can form a strong carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two.

[0075] In addition, since the solder layer and the soldering aid layer of the present invention are separated, during reflow soldering, the soldering aid layer can melt prior to the solder layer, form a strong carbon-containing compound with the metal on the substrate, and fully fill the fine gaps between the electrode and the substrate. Since the present invention can adjust the thickness of the soldering aid layer through the process to control the amount of the soldering flux, the heat preservation time during the reflow soldering process can be shortened.

[0076] Specifically, the soldering aid layer of the present invention is made of a soldering aid, and the viscosity of the soldering aid is 200-600 kcps, and the residue after reflow soldering is less than 50%.

[0077] Among them, the viscosity of the soldering aid plays an important role in the soldering of the chip. If the viscosity of the soldering aid is too low, it is difficult to form on the solder layer, and the thickness is difficult to control, and it is also easy to overflow during reflow soldering; if the viscosity of the soldering aid is too high, it is difficult to fully fill the fine gaps between the electrodes and the substrate during reflow soldering.

[0078] Theoretically, the smaller the residue of the soldering aid after reflow soldering, the better. Since the soldering aid of the present invention has been formed at the chip stage and its thickness can be controlled, the residue of the soldering aid of the present invention only needs to be less than 50% after reflow soldering.

[0079] Preferably, the viscosity of the soldering aid is 300-500 kcps, and the residue after reflow soldering is less than 40%.

[0080] More preferably, the viscosity of the soldering aid is 400-450 kcps, and the residue after reflow soldering is less than 40%.

[0081] Among them, the material of the soldering aid layer is selected from rosin and / or resin.

[0082] The resin is a thermosetting resin, and is selected from one or more of unsaturated polyester, vinyl ester, epoxy type maleimide resin, phenolic type maleimide resin, bismaleimide resin, and polyimide resin. The above resins can be quickly hardened by heat and are easy to volatilize, and become electrically conductive carbon atoms at high temperature, effectively filling the fine gaps between the electrodes and the substrate. The above materials can be formed by spin coating or spraying, and the manufacturing method is simple.

[0083] Preferably, the rosin contains 1%-5% by mass of a halogen compound. Adding a certain amount of halogen compound to the rosin in the present invention can make the soldering aid form a stronger carbon-containing compound with the metal on the substrate, further improving the bonding strength between the two. Among them, the halogen compound is a compound containing one or more elements of fluorine, chlorine, bromine, iodine, and astatine. Since the halogen itself has high activity, the reaction can be accelerated.

[0084] Specifically, the soldering aid layer is formed on the solder layer by spin coating or spraying.

[0085] Among them, the thickness of the soldering aid layer plays an important role in the subsequent packaging and soldering of the chip. If the thickness of the soldering aid layer is too thick, it is easy to overflow during soldering, resulting in chip leakage; if the thickness of the soldering aid layer is too small, the chip and the substrate are not firmly combined, reducing the soldering yield.

[0086] Preferably, the thickness of the soldering aid layer is 2-20 μm. More preferably, the thickness of the soldering aid layer is 5-15 μm. Most preferably, the thickness of the soldering aid layer is 8-15 μm.

[0087] V. A protective layer is formed on the solder layer and the soldering aid layer, and the protective layer wraps the soldering aid layer;

[0088] Since the soldering aid layer has a certain viscosity, in order to avoid adhesion of some impurities on the soldering aid layer and affect the performance of the soldering aid layer, the protective layer of the present invention is provided on the solder layer and the soldering aid layer and wraps the soldering aid layer for easy storage and transportation.

[0089] Preferably, the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene and wax. The above materials can be formed by spin coating or spraying. The manufacturing method is simple, effectively protects the soldering aid layer, and will not affect the soldering aid layer and soldering. Specifically, the above materials will instantly shrink into a small molecule state at high temperature and do not affect soldering.

[0090] Among them, the thickness of the protective layer is 1-10 μm. Preferably, the thickness of the protective layer is 3-7 μm. More preferably, the thickness of the protective layer is 4-6 μm.

[0091] Correspondingly, the present invention also provides a packaging method for flip-chip Mini / Micro-LED chips, including:

[0092] A. Place the above flip-chip Mini / Micro-LED chip on the substrate, wherein the welding layer of the flip-chip Mini / Micro-LED chip is aligned with the pad on the substrate;

[0093] B. Heat the substrate. After the welding layer melts, it adheres between the flip-chip Mini / Micro-LED chip and the substrate, and the soldering aid layer and the pad form a carbon-containing compound.

[0094] Preferably, in step (B), the substrate is heated in a gradient manner, and a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone and a seventh temperature zone are set. Among them, 150°C < the temperature of the first temperature zone < the temperature of the second temperature zone < the temperature of the third temperature zone < the temperature of the fourth temperature zone < the temperature of the fifth temperature zone < the temperature of the sixth temperature zone < the temperature of the seventh temperature zone < 250°C.

[0095] More preferably, the temperature of the first temperature zone is 160-165°C, the temperature of the second temperature zone is 170-175°C, the temperature of the third temperature zone is 180-185°C, the temperature of the fourth temperature zone is 190-195°C, the temperature of the fifth temperature zone is 200-205°C, the temperature of the sixth temperature zone is 210-215°C, and the temperature of the seventh temperature zone is 220-225°C.

[0096] Through the method of gradient zoning heating, the present invention enables the soldering layer and the solder assisting layer to be fully melted, perfectly bonded between the electrode and the substrate, effectively preventing solder overflow, and fully filling the fine gaps between the electrode and the substrate, further improving the bonding strength between the electrode and the substrate, with the void ratio after soldering being less than 10%. In addition, through gradient heating, the solder assisting layer can form more solid carbon-containing compounds with the metal on the substrate, further improving the bonding strength between the two.

[0097] The packaging method of the present invention saves equipment such as solder paste printers and dispensing machines, simplifies the entire packaging production process, effectively shortens the packaging time, and greatly reduces costs.

[0098] The above-disclosed is only a preferred embodiment of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. Flip-chip Mini / Micro-LED chips that are easy to solder, characterized in that, it includes a substrate, a light-emitting structure provided on the substrate, an electrode provided on the light-emitting structure, and a solder layer provided on the electrode; the solder layer includes a solder layer, a soldering aid layer provided on the solder layer, and a protective layer provided on the solder layer and the soldering aid layer and wrapping the soldering aid layer; wherein, the material of the solder layer is selected from one or more of tin-lead solder, silver solder, copper solder, and pure tin solder; the soldering aid layer is made of a soldering aid, the viscosity of the soldering aid is 200~600 kcps, and the residue after reflow soldering is less than 50%; when soldering, the soldering aid layer forms a carbon-containing compound with the metal on the substrate, and the thickness of the soldering aid layer is 2~20 μm; the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax; the material of the protective layer will instantly shrink into a small molecule state at high temperature and does not affect soldering; the thickness of the protective layer is 1~10 μm.

2. The flip-chip Mini / Micro-LED chip that is easy to solder according to claim 1, characterized in that, the material of the soldering aid layer is selected from rosin and / or resin; the resin is a thermosetting resin and is selected from one or more of unsaturated polyester, vinyl ester, epoxy-type maleimide resin, phenolic-type maleimide resin, bismaleimide resin, and polyimide resin.

3. The flip-chip Mini / Micro-LED chip that is easy to solder according to claim 2, characterized in that, the rosin contains 1%~5% by mass of a halogen compound, and the halogen compound is a compound containing one or more elements of fluorine, chlorine, bromine, iodine, and astatine.

4. The flip-chip Mini / Micro-LED chip that is easy to solder according to claim 1, characterized in that, the thickness of the solder layer is 10~100 μm.

5. A manufacturing method of a flip-chip Mini / Micro-LED chip that is easy to solder, characterized in that, it includes: I. Form a light-emitting structure on the substrate; II. Form an electrode on the light-emitting structure; III. Form a solder layer on the electrode, and the material of the solder layer is selected from one or more of tin-lead solder, silver solder, copper solder, and pure tin solder; IV. Form a soldering aid layer on the solder layer, the soldering aid layer is made of a soldering aid, the viscosity of the soldering aid is 200~600 kcps, and the residue after reflow soldering is less than 50%; when soldering, the soldering aid layer forms a carbon-containing compound with the metal on the substrate, and the thickness of the soldering aid layer is 2~20 μm; V. Form a protective layer on the solder layer and the soldering aid layer, the protective layer wraps the soldering aid layer, and the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax; the material of the protective layer will instantly shrink into a small molecule state at high temperature and does not affect soldering; the thickness of the protective layer is 1~10 μm.

6. The manufacturing method of the flip-chip Mini / Micro-LED chip that is easy to solder according to claim 5, characterized in that, In step (III), a solder layer is formed on the electrode by means of yellow light evaporation coating or stencil printing, and the thickness of the solder layer is 10 - 100 μm; In step (IV), a soldering aid layer is formed on the solder layer by means of spin coating or spraying; In step (V), a protective layer is formed on the soldering aid layer by means of spin coating or spraying.

7. A packaging method for a flip-chip Mini / Micro-LED chip, characterized in that, it includes: A. Place the flip-chip Mini / Micro-LED chip described in any one of claims 1 - 4 on a substrate, wherein the welding layer of the flip-chip Mini / Micro-LED chip is aligned with the pads on the substrate; B. Heat the substrate, and the welding layer adheres between the flip-chip Mini / Micro-LED chip and the substrate, and the soldering aid layer and the pads form a carbon-containing compound.

8. The packaging method for a flip-chip Mini / Micro-LED chip as claimed in claim 7, characterized in that, in step (B), the substrate is heated in a gradient manner, and the first temperature zone, the second temperature zone, the third temperature zone, the fourth temperature zone, the fifth temperature zone, the sixth temperature zone and the seventh temperature zone are set, wherein, 150°C < the temperature of the first temperature zone < the temperature of the second temperature zone < the temperature of the third temperature zone < the temperature of the fourth temperature zone < the temperature of the fifth temperature zone < the temperature of the sixth temperature zone < the temperature of the seventh temperature zone < 250°C.

9. The packaging method for a flip-chip Mini / Micro-LED chip as claimed in claim 8, characterized in that, the temperature of the first temperature zone is 160 - 165°C, the temperature of the second temperature zone is 170 - 175°C, the temperature of the third temperature zone is 180 - 185°C, the temperature of the fourth temperature zone is 190 - 195°C, the temperature of the fifth temperature zone is 200 - 205°C, the temperature of the sixth temperature zone is 210 - 215°C, and the temperature of the seventh temperature zone is 220 - 225°C.

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