CN112242477A - Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof - Google Patents
Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof Download PDFInfo
- Publication number
- CN112242477A CN112242477A CN202011116185.4A CN202011116185A CN112242477A CN 112242477 A CN112242477 A CN 112242477A CN 202011116185 A CN202011116185 A CN 202011116185A CN 112242477 A CN112242477 A CN 112242477A
- Authority
- CN
- China
- Prior art keywords
- layer
- welding
- solder
- temperature
- temperature zone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
- H01L2933/0066—Processes relating to semiconductor body packages relating to arrangements for conducting electric current to or from the semiconductor body
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Led Device Packages (AREA)
Abstract
The invention discloses an easily-welded inverted Mini/Micro-LED chip, a preparation method and a packaging method thereof. The Mini/Micro-LED chip is easy to weld and package, and has high packaging efficiency, high yield and low cost.
Description
Technical Field
The invention relates to the technical field of light emitting diodes, in particular to an easily-welded inverted Mini/Micro-LED chip and a preparation method and a packaging method thereof.
Background
The flip LED chip has the characteristic of no packaging, so that the wire bonding time and the cost of a downstream packaging factory are greatly reduced. Although the wire bonding step can be omitted, solder and flux are applied to the electrodes to electrically connect the electrodes of the LED chip and the substrate.
The Mini/Micro-LED chip has smaller bonding pad, less solder paste amount and smaller chip, and has higher requirements on the technological parameters of welding equipment, temperature uniformity and the like. Problems with current welding include: 1. chip displacement: movement after die bonding is required to be reduced; 2. chip rotation: because the distance between the Mini/Micro-LED chips is only 0.8mm, 0.6mm, 0.4mm or even smaller, the chips are easy to rotate under the atmosphere environment in the welding process, and the influence is bad; 3. the void ratio is high: after the prior nitrogen reflow soldering, the low voidage solder paste is adopted, and the voidage after the soldering is controlled to be about 10 percent; in the common solder paste, the voidage after soldering can reach more than 15%, and the voidage is too high, so that the product is poor due to the heat conduction effect or the reliability problem after long-term use. A circuit board with 9000 chips is a big thing with several defects that result in a defective final product.
In addition, the existing coating methods of the solder and the soldering flux are generally divided into a solder paste dispensing method and a solder paste brushing method, wherein the solder paste dispensing method has the advantages of high speed, low precision, large glue consumption, easy overflow and easy displacement and short circuit of a chip; the solder paste brushing method has high precision, but slow speed and high machine price. Therefore, the step of brushing the solder paste on the Mini/Micro-LED chip can greatly obstruct the pushing of the Mini/Micro-LED chip flip product.
Disclosure of Invention
The invention aims to solve the technical problem of providing an easily-welded inverted Mini/Micro-LED chip and a preparation method thereof, which are easy to weld and package, high in packaging efficiency, high in yield and low in cost.
The invention also aims to solve the technical problem of providing an easy-to-weld packaging method for the inverted Mini/Micro-LED chip, which has the advantages of high packaging efficiency, high yield and low cost.
In order to solve the technical problem, the invention provides an easily-welded inverted Mini/Micro-LED chip which comprises a substrate, a light-emitting structure arranged on the substrate, an electrode arranged on the light-emitting structure and a welding layer arranged on the electrode;
the welding layer comprises a welding flux layer, a welding-assistant layer arranged on the welding flux layer and a protective layer arranged on the welding flux layer and the welding-assistant layer and wrapping the welding-assistant layer; wherein the content of the first and second substances,
the welding-assistant layer is made of a soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%;
the material of the welding-assistant layer is selected from one or more of rosin, resin and halogen-containing compounds;
the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene and wax.
The material for improving the welding assistant layer in the scheme is selected from rosin and/or resin;
the resin is 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.
As an improvement of the scheme, the thickness of the solder layer is 10-100 μm;
the thickness of the welding-assistant layer is 2-20 mu m.
As an improvement of the scheme, the thickness of the protective layer is 1-10 mu m.
Correspondingly, the invention also provides a manufacturing method of the flip Mini/Micro-LED chip easy to weld, which comprises the following steps:
firstly, forming a light-emitting structure on a substrate;
secondly, forming an electrode on the light-emitting structure;
forming a solder layer on the electrode, wherein the solder layer is made of one or more materials selected from tin-lead solder, silver solder, copper solder and pure tin solder;
forming a soldering flux layer on the solder layer, wherein the soldering flux layer is made of soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%;
and fifthly, forming a protective layer on the solder layer and the welding-assistant layer, wherein the welding-assistant layer is wrapped by the protective layer, and the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene and wax.
As an improvement of the scheme, a solder layer is formed on the electrode by adopting a yellow light evaporation or steel mesh printing mode, and the thickness of the solder layer is 10-100 mu m;
in the step (IV), a welding-assistant layer is formed on the solder layer in a rotary coating or spraying mode, and the thickness of the welding-assistant layer is 2-20 microns;
and (V) forming a protective layer on the welding-assistant layer in a rotary coating or spraying mode, wherein the thickness of the protective layer is 1-10 mu m.
Correspondingly, the invention also provides a packaging method for the flip Mini/Micro-LED chip, which comprises the following steps:
A. placing the inverted Mini/Micro-LED chip on a substrate, wherein a welding layer of the inverted Mini/Micro-LED chip is aligned with a bonding pad on the substrate;
B. and heating the substrate, bonding the welding layer between the inverted Mini/Micro-LED chip and the substrate, and forming a carbon-containing compound between the welding-assistant layer and the bonding pad.
As an improvement of the above scheme, in the step (B), the substrate is subjected to gradient heating, 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 provided, wherein the temperature of the first temperature zone is higher than 150 ℃ < 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 ℃.
As an improvement of the scheme, the temperature of the first temperature zone is 160-165 ℃, the temperature of the second temperature zone is 170-175 ℃, the temperature of the third temperature zone is 180-185 ℃, the temperature of the fourth temperature zone is 190-195 ℃, the temperature of the fifth temperature zone is 200-205 ℃, the temperature of the sixth temperature zone is 210-215 ℃, and the temperature of the seventh temperature zone is 220-225 ℃.
The implementation of the invention has the following beneficial effects:
in the wafer stage of the LED, the solder layers are formed on the electrodes of the plurality of light-emitting structures simultaneously, compared with the packaging method of one-by-one LED chip solder paste dispensing and solder paste brushing, the efficiency is greatly improved, the using amount of the solder paste can be accurately controlled by controlling the thickness of the solder layer, the excessive or insufficient using amount of the solder paste is avoided, the bonding force between the chip and the substrate is effectively ensured, and meanwhile, the chip is prevented from rotating and shifting, so that the welding yield of the LED chip and the substrate is improved.
In addition, the welding-assistant layer is arranged on the solder layer, so that the gap of the detail between the electrode and the substrate is further filled, and the void ratio after welding is less than 10 percent; more importantly, the welding assistant layer can form a firm carbon-containing compound with the metal on the substrate during welding, and the bonding strength of the welding assistant layer and the metal on the substrate is further improved.
Furthermore, the protective layer is arranged on the solder layer and the welding-assistant layer and wraps the welding-assistant layer, so that the protective layer is used for protecting the welding-assistant layer, preventing dust, impurities and the like from being adhered to the welding-assistant layer, ensuring the performance of the welding-assistant layer and facilitating storage and transportation.
According to the invention, by adopting a gradient zone heating method, the welding layer and the welding-aid layer are fully melted and perfectly bonded between the electrode and the substrate, so that the solder is effectively prevented from overflowing, the gaps of the details between the electrode and the substrate are fully filled, the bonding strength of the electrode and the substrate is further improved, and the void ratio after welding is less than 10%; in addition, the soldering assistant layer can form more firm carbon-containing compounds with the metal on the substrate through gradual heating, and the bonding strength of the soldering assistant layer and the metal is further improved.
The packaging method saves devices such as a solder paste brushing machine, a glue dispenser and the like, simplifies the whole packaging production flow, effectively shortens the packaging time and greatly reduces the cost.
Drawings
FIG. 1 is a schematic structural diagram of a flip Mini/Micro-LED chip of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, the flip Mini/Micro-LED chip easy to solder provided by the present invention comprises a substrate 10, a light emitting structure 20 disposed on the substrate 10, an electrode 30 disposed on the light emitting structure 20, and a solder layer 40 disposed on the electrode 30, wherein the size of the flip Mini/Micro-LED chip is less than 100 μm.
The soldering layer 40 includes a solder layer 41, a solder assistant layer 42 disposed on the solder layer 41, and a passivation layer 43 disposed on the solder layer 41 and the solder assistant layer 42 and covering the solder assistant layer 42.
The solder layer of the present invention is used for bonding an electrode and a substrate, and 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 for filling up the gap between the electrode and the substrate, reducing the unevenness between the chip and the substrate, reducing the void ratio between the chip and the substrate, and increasing the reliability of the solder layer, so the material of the solder layer must have 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.
The thickness of the solder layer plays an important role in subsequent welding and packaging of the chip, and if the thickness of the solder layer is too thick, the solder layer is easy to overflow during welding, so that the chip leaks electricity; if the thickness of the solder layer is too small, the chip and the substrate are not firmly bonded, and the bonding yield is reduced.
Preferably, the thickness of the solder layer is 10 to 100 μm. More preferably, the thickness of the solder layer is 20-80 μm. Optimally, the thickness of the solder layer is 40-60 mu m.
Specifically, the invention adopts a yellow light evaporation or steel mesh printing mode to form a solder layer on the electrode. In the wafer stage of the LED, the solder layers are formed on the electrodes of the plurality of light-emitting structures simultaneously, compared with the packaging method of one-by-one LED chip solder paste dispensing and solder paste brushing, the efficiency is greatly improved, the using amount of the solder paste can be accurately controlled by controlling the thickness of the solder layer, the excessive or insufficient using amount of the solder paste is avoided, the bonding force between the chip and the substrate is effectively ensured, and meanwhile, the chip is prevented from rotating and shifting, so that the welding yield of the LED chip and the substrate is improved.
The existing welding method of the flip LED chip is to mix solder and soldering flux to form solder paste, then to coat the solder paste on a welding pad of a substrate, then to weld the flip LED chip, and finally to perform reflow welding. Because the solder and the soldering flux are mixed in the prior method, the soldering flux in the soldering paste can be volatilized completely to remove the oxides of the bonding pad and the chip electrode by carrying out long-time heat preservation in the reflow soldering process.
The welding flux and the soldering flux are separated to form the welding flux layer and the soldering assistant layer, wherein the soldering assistant layer is arranged on the welding flux layer, so that the gap of the details between the electrode and the substrate can be filled, and the voidage after welding is less than 10%; more importantly, the welding assistant layer can form a firm carbon-containing compound with the metal on the substrate during welding, and the bonding strength of the welding assistant layer and the metal on the substrate is further improved.
In addition, the solder layer and the soldering assistant layer are separated, and during reflow soldering, the soldering assistant layer can be melted before the solder layer, so that a firm carbon-containing compound is formed with the metal on the substrate and is fully filled in the gap of the detail between the electrode and the substrate. The invention can adjust the thickness of the soldering flux layer through the process, thereby controlling the dosage of the soldering flux, and shortening the heat preservation time in the reflow soldering process.
Specifically, the welding assistant layer is made of the soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%.
The viscosity of the flux plays an important role in the soldering of the chip, and if the viscosity of the flux is too low, the flux is difficult to form on a solder layer, the thickness of the flux is difficult to control, and the flux is easy to overflow during reflow soldering; if the viscosity of the flux is too high, it is difficult to sufficiently fill the gap in the fine portion between the electrode and the substrate during reflow soldering.
Theoretically, the smaller the residue after reflow soldering of the soldering flux, the better, since the soldering flux of the present invention is formed in the chip stage and the thickness of the soldering flux can be controlled, the residue after reflow soldering of the soldering flux of the present invention is only required to be less than 50%.
Preferably, the viscosity of the soldering flux is 300-500 kcps, and the residue after reflow is less than 40%.
Preferably, the viscosity of the soldering flux is 400-450 kcps, and the residue after reflow is less than 40%.
Wherein the material of the welding assistant layer is selected from rosin and/or resin.
The resin is thermosetting resin and is selected from one or more of unsaturated polyester, vinyl ester, epoxy maleimide resin, phenolic maleimide resin, bismaleimide resin and polyimide resin, the resin can be quickly hardened by heating and is easy to volatilize, and the resin becomes conductive carbon atoms at high temperature, so that gaps between the electrode and the substrate can be effectively filled. The material can be formed by spin coating or spraying, and the manufacturing method is simple.
Preferably, the rosin contains 1 to 5 mass% of a halogen compound. According to the invention, a certain amount of halogen compound is added into the rosin, so that a firmer carbon-containing compound is formed between the soldering flux and the metal on the substrate, and the bonding strength of the soldering flux and the metal on the substrate is further improved. Wherein, the halogen compound is a compound containing one or more elements of fluorine, chlorine, bromine, iodine and astatine, and the halogen has higher activity, so the reaction can be accelerated.
The thickness of the welding-assistant layer plays an important role in the subsequent packaging and welding of the chip, and if the thickness of the welding-assistant layer is too thick, the welding easily overflows to cause electric leakage of the chip; if the thickness of the solder mask layer is too small, the chip and the substrate are not firmly bonded, and the yield of soldering is reduced.
Preferably, the thickness of the welding assistant layer is 2-20 μm. Preferably, the thickness of the welding-assistant layer is 5-15 μm. Optimally, the thickness of the welding assistant layer is 8-15 mu m.
Because the welding-assistant layer has certain viscosity, in order to avoid the adhesion of impurities on the welding-assistant layer and influence the performance of the welding-assistant layer, the protective layer is arranged on the welding-assistant layer and wraps the welding-assistant layer, so that the welding-assistant layer is convenient to store and transport.
Preferably, the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax. The material can be formed in a spin coating or spraying mode, the manufacturing method is simple, the welding-assistant layer is effectively protected, the welding-assistant layer and welding cannot be affected, and specifically, the material can be instantly shrunk into a small molecular state at high temperature, and welding cannot be affected.
Wherein 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.
Correspondingly, the invention also provides a manufacturing method of the flip Mini/Micro-LED chip easy to weld, which comprises the following steps:
firstly, forming a light-emitting structure on a substrate;
specifically, a plurality of light emitting structures are arranged on the substrate.
Secondly, forming an electrode on the light-emitting structure;
wherein, each light emitting structure is provided with an electrode, the electrode comprises a positive electrode and a negative electrode, and the electrode can be an existing electrode structure, and the invention is not limited in particular.
Thirdly, forming a solder layer on the electrode;
the solder layer of the present invention is used for bonding an electrode and a substrate, and 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 for filling up the gap between the electrode and the substrate, reducing the unevenness between the chip and the substrate, reducing the void ratio between the chip and the substrate, and increasing the reliability of the solder layer, so the material of the solder layer must have 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.
The thickness of the solder layer plays an important role in the subsequent packaging and welding of the chip, and if the thickness of the solder layer is too thick, the solder layer is easy to overflow during welding, so that the chip leaks electricity; if the thickness of the solder layer is too small, the chip and the substrate are not firmly bonded, and the bonding yield is reduced.
Preferably, the thickness of the solder layer is 10 to 100 μm. More preferably, the thickness of the solder layer is 20-80 μm. Optimally, the thickness of the solder layer is 40-60 mu m.
Specifically, the invention adopts a yellow light evaporation or steel mesh printing mode to form a solder layer on the electrode. In the wafer stage of the LED, the solder layers are formed on the electrodes of the plurality of light-emitting structures simultaneously, compared with the packaging method of one-by-one LED chip solder paste dispensing and solder paste brushing, the efficiency is greatly improved, the using amount of the solder paste can be accurately controlled by controlling the thickness of the solder layer, the excessive or insufficient using amount of the solder paste is avoided, the bonding force between the chip and the substrate is effectively ensured, and meanwhile, the chip is prevented from rotating and shifting, so that the welding yield of the LED chip and the substrate is improved.
Fourthly, forming a soldering assistant layer on the solder layer;
the welding-assistant layer is arranged on the solder layer, so that the gap between the electrode and the substrate is further filled, more importantly, the welding-assistant layer can form firm carbon-containing compounds with metal on the substrate during welding, and the bonding strength of the welding-assistant layer and the metal on the substrate is further improved.
The existing welding method of the flip LED chip is to mix solder and soldering flux to form solder paste, then to coat the solder paste on a welding pad of a substrate, then to weld the flip LED chip, and finally to perform reflow welding. Because the solder and the soldering flux are mixed in the prior method, the soldering flux in the soldering paste can be volatilized completely to remove the oxides of the bonding pad and the chip electrode by carrying out long-time heat preservation in the reflow soldering process.
The welding flux and the soldering flux are separated to form the welding flux layer and the soldering assistant layer, wherein the soldering assistant layer is arranged on the welding flux layer, so that the gap of the details between the electrode and the substrate can be filled, and the voidage after welding is less than 10%; more importantly, the welding assistant layer can form a firm carbon-containing compound with the metal on the substrate during welding, and the bonding strength of the welding assistant layer and the metal on the substrate is further improved.
In addition, the solder layer and the soldering assistant layer are separated, and during reflow soldering, the soldering assistant layer can be melted before the solder layer, so that a firm carbon-containing compound is formed with the metal on the substrate and is fully filled in the gap of the detail between the electrode and the substrate. The invention can adjust the thickness of the soldering flux layer through the process, thereby controlling the dosage of the soldering flux, and shortening the heat preservation time in the reflow soldering process.
Specifically, the welding assistant layer is made of the soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%.
The viscosity of the flux plays an important role in the soldering of the chip, and if the viscosity of the flux is too low, the flux is difficult to form on a solder layer, the thickness of the flux is difficult to control, and the flux is easy to overflow during reflow soldering; if the viscosity of the flux is too high, it is difficult to sufficiently fill the gap in the fine portion between the electrode and the substrate during reflow soldering.
Theoretically, the smaller the residue after reflow soldering of the soldering flux, the better, since the soldering flux of the present invention is formed in the chip stage and the thickness of the soldering flux can be controlled, the residue after reflow soldering of the soldering flux of the present invention is only required to be less than 50%.
Preferably, the viscosity of the soldering flux is 300-500 kcps, and the residue after reflow is less than 40%.
Preferably, the viscosity of the soldering flux is 400-450 kcps, and the residue after reflow is less than 40%.
Wherein the material of the welding assistant layer is selected from rosin and/or resin.
The resin is thermosetting resin and is selected from one or more of unsaturated polyester, vinyl ester, epoxy maleimide resin, phenolic maleimide resin, bismaleimide resin and polyimide resin, the resin can be quickly hardened by heating and is easy to volatilize, and the resin becomes conductive carbon atoms at high temperature, so that gaps between the electrode and the substrate can be effectively filled. The material can be formed by spin coating or spraying, and the manufacturing method is simple.
Preferably, the rosin contains 1 to 5 mass% of a halogen compound. According to the invention, a certain amount of halogen compound is added into the rosin, so that a firmer carbon-containing compound is formed between the soldering flux and the metal on the substrate, and the bonding strength of the soldering flux and the metal on the substrate is further improved. Wherein, the halogen compound is a compound containing one or more elements of fluorine, chlorine, bromine, iodine and astatine, and the halogen has higher activity, so the reaction can be accelerated.
Specifically, the solder-assisting layer is formed on the solder layer by spin coating or spraying.
The thickness of the welding-assistant layer plays an important role in the subsequent packaging and welding of the chip, and if the thickness of the welding-assistant layer is too thick, the welding easily overflows to cause electric leakage of the chip; if the thickness of the solder mask layer is too small, the chip and the substrate are not firmly bonded, and the yield of soldering is reduced.
Preferably, the thickness of the welding assistant layer is 2-20 μm. Preferably, the thickness of the welding-assistant layer is 5-15 μm. Optimally, the thickness of the welding assistant layer is 8-15 mu m.
Fifthly, forming a protective layer on the solder layer and the soldering assistant layer, wherein the protective layer wraps the soldering assistant layer;
because the welding-assistant layer has certain viscosity, in order to avoid the adhesion of impurities on the welding-assistant layer and influence the performance of the welding-assistant layer, the protective layer is arranged on the welding-assistant layer and wraps the welding-assistant layer, so that the welding-assistant layer is convenient to store and transport.
Preferably, the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene, and wax. The material can be formed in a spin coating or spraying mode, the manufacturing method is simple, the welding-assistant layer is effectively protected, the welding-assistant layer and welding cannot be affected, and specifically, the material can be instantly shrunk into a small molecular state at high temperature, and welding cannot be affected.
Wherein 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.
Correspondingly, the invention also provides a packaging method for the flip Mini/Micro-LED chip, which comprises the following steps:
A. placing the inverted Mini/Micro-LED chip on a substrate, wherein a welding layer of the inverted Mini/Micro-LED chip is aligned with a bonding pad on the substrate;
B. and heating the substrate, bonding the welding layer between the inverted Mini/Micro-LED chip and the substrate after the welding layer is melted, and forming a carbon-containing compound between the welding-assistant layer and the bonding pad.
Preferably, in the step (B), the substrate is gradient-heated, 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 provided, wherein a temperature of 150 ℃ < the first temperature zone < a temperature of the second temperature zone < a temperature of the third temperature zone < a temperature of the fourth temperature zone < a temperature of the fifth temperature zone < a temperature of the sixth temperature zone < a temperature of the seventh temperature zone < 250 ℃.
Preferably, the temperature of the first temperature zone is 160-165 ℃, the temperature of the second temperature zone is 170-175 ℃, the temperature of the third temperature zone is 180-185 ℃, the temperature of the fourth temperature zone is 190-195 ℃, the temperature of the fifth temperature zone is 200-205 ℃, the temperature of the sixth temperature zone is 210-215 ℃, and the temperature of the seventh temperature zone is 220-225 ℃.
The invention leads the welding layer and the welding-aid layer to be fully melted by a gradient zone heating method and be perfectly adhered between the electrode and the substrate, thereby effectively preventing the solder from overflowing, fully filling the gap of the detail between the electrode and the substrate, further improving the bonding strength of the electrode and the substrate, and leading the void ratio after welding to be less than 10 percent. In addition, the soldering assistant layer can form more firm carbon-containing compounds with the metal on the substrate through gradual heating, and the bonding strength of the soldering assistant layer and the metal is further improved.
The packaging method saves devices such as a solder paste brushing machine, a glue dispenser and the like, simplifies the whole packaging production flow, effectively shortens the packaging time and greatly reduces the cost.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (10)
1. The flip Mini/Micro-LED chip easy to weld is characterized by comprising a substrate, a light-emitting structure arranged on the substrate, an electrode arranged on the light-emitting structure and a welding layer arranged on the electrode;
the welding layer comprises a welding flux layer, a welding-assistant layer arranged on the welding flux layer and a protective layer arranged on the welding flux layer and the welding-assistant layer and wrapping the welding-assistant layer; wherein the content of the first and second substances,
the solder layer is made of one or more materials selected from tin-lead solder, silver solder, copper solder and pure tin solder;
the welding-assistant layer is made of a soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%;
the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene and wax.
2. The easy-to-solder flip Mini/Micro-LED chip of claim 1, wherein the material of the solder flux layer is selected from rosin and/or resin;
the resin is 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 easy-to-solder flip-chip Mini/Micro-LED chip of claim 2, wherein the rosin comprises 1% to 5% by mass of a halogen compound comprising one or more of fluorine, chlorine, bromine, iodine and astatine.
4. The flip Mini/Micro-LED chip easy to solder according to claim 1, wherein the solder layer has a thickness of 10 to 100 μm;
the thickness of the welding-assistant layer is 2-20 mu m.
5. The flip-chip Mini/Micro-LED chip of claim 1, wherein the protective layer has a thickness of 1 to 10 μm.
6. A manufacturing method of an easily-welded inverted Mini/Micro-LED chip is characterized by comprising the following steps:
firstly, forming a light-emitting structure on a substrate;
secondly, forming an electrode on the light-emitting structure;
forming a solder layer on the electrode, wherein the solder layer is made of one or more materials selected from tin-lead solder, silver solder, copper solder and pure tin solder;
forming a soldering flux layer on the solder layer, wherein the soldering flux layer is made of soldering flux, the viscosity of the soldering flux is 200-600 kcps, and the residue after reflow is less than 50%;
and fifthly, forming a protective layer on the solder layer and the welding-assistant layer, wherein the welding-assistant layer is wrapped by the protective layer, and the material of the protective layer is selected from one of polyethylene, ethylene-tetrafluoroethylene and wax.
7. The method for manufacturing the flip Mini/Micro-LED chip easy to solder according to claim 6, wherein in the third step, a solder layer is formed on the electrode by yellow light evaporation or steel screen printing, and the thickness of the solder layer is 10-100 μm;
in the step (IV), a welding-assistant layer is formed on the solder layer in a rotary coating or spraying mode, and the thickness of the welding-assistant layer is 2-20 microns;
and (V) forming a protective layer on the welding-assistant layer in a rotary coating or spraying mode, wherein the thickness of the protective layer is 1-10 mu m.
8. A packaging method for flip-chip Mini/Micro-LED chips is characterized by comprising the following steps:
A. placing the flip Mini/Micro-LED chip of any of claims 1 to 5 on a substrate, wherein the solder layer of the flip Mini/Micro-LED chip is aligned with the pads on the substrate;
B. and heating the substrate, bonding the welding layer between the inverted Mini/Micro-LED chip and the substrate, and forming a carbon-containing compound between the welding-assistant layer and the bonding pad.
9. The method of claim 8, wherein in step (B), the substrate is subjected to gradient heating, 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 arranged, wherein the temperature of 150 ℃ < 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 ℃.
10. The flip-chip Mini/Micro-LED chip packaging method of claim 9, wherein the temperature of the first temperature zone is 160-165 ℃, the temperature of the second temperature zone is 170-175 ℃, the temperature of the third temperature zone is 180-185 ℃, the temperature of the fourth temperature zone is 190-195 ℃, the temperature of the fifth temperature zone is 200-205 ℃, the temperature of the sixth temperature zone is 210-215 ℃, and the temperature of the seventh temperature zone is 220-225 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011116185.4A CN112242477A (en) | 2020-10-19 | 2020-10-19 | Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011116185.4A CN112242477A (en) | 2020-10-19 | 2020-10-19 | Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112242477A true CN112242477A (en) | 2021-01-19 |
Family
ID=74169104
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011116185.4A Pending CN112242477A (en) | 2020-10-19 | 2020-10-19 | Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112242477A (en) |
-
2020
- 2020-10-19 CN CN202011116185.4A patent/CN112242477A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6333554B1 (en) | Semiconductor device with gold bumps, and method and apparatus of producing the same | |
| US5990564A (en) | Flip chip packaging of memory chips | |
| US8076232B2 (en) | Semiconductor device and method of forming composite bump-on-lead interconnection | |
| US9935091B2 (en) | Package-on-package structures and methods for forming the same | |
| JP2006261641A (en) | Semiconductor package assembly | |
| CN101958298A (en) | Semiconductor device and manufacture method thereof | |
| US20040235221A1 (en) | Electronic device and method for manufacturing the same | |
| TW201225210A (en) | Semiconductor device and method of forming high routing density interconnect sites on substrate | |
| US8431478B2 (en) | Solder cap bump in semiconductor package and method of manufacturing the same | |
| KR102006637B1 (en) | Method Of Forming Bump And Semiconductor device including The Same | |
| CN102208358A (en) | Method for soldering flip chip on base plate and packaging apparatus | |
| CN112242477A (en) | Easily-welded inverted Mini/Micro-LED chip and preparation method and packaging method thereof | |
| JP5560713B2 (en) | Electronic component mounting method, etc. | |
| CN213340422U (en) | Easily-welded inverted Mini/Micro-LED chip | |
| JP4366838B2 (en) | Method for manufacturing electronic circuit module | |
| US11239190B2 (en) | Solder-metal-solder stack for electronic interconnect | |
| CN114937661A (en) | Backlight module and manufacturing method thereof | |
| US20090026633A1 (en) | Flip chip package structure and method for manufacturing the same | |
| USRE44500E1 (en) | Semiconductor device and method of forming composite bump-on-lead interconnection | |
| US7944051B2 (en) | Semiconductor device having external connection terminals and method of manufacturing the same | |
| JP2012124427A (en) | Manufacturing method of electronic component and manufacturing method of semiconductor device | |
| JP4266956B2 (en) | Semiconductor device manufacturing method and manufacturing apparatus | |
| KR102101346B1 (en) | Light emitting diode flipchip array and bonding method of the same | |
| JP4302181B2 (en) | Semiconductor device manufacturing equipment | |
| JP3703808B2 (en) | Manufacturing method of semiconductor device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |