CN104600183A - Preparation method of LED white light diode - Google Patents

Abstract

The invention discloses a method for preparing an LED white light diode. The LED white light diode comprises first and second leads, a blue LED chip and an epoxy resin adhesive layer containing yellow fluorescent powder. The first and second leads are respectively integrated with each other. The first and second SMD base islands and the first and second pins, the blue LED chip is mounted on the first SMD base island and electrically connected to the first SMD base island, the surface of the blue LED chip is in contact with the first SMD base island The second patch base island is electrically connected, and the first patch base island, the second patch base island and the blue LED chip are covered in an epoxy resin adhesive layer containing yellow phosphor; and it: the The steps of the preparation method of LED white light diodes are: step a, preparing solid epoxy resin cake material containing fluorescent powder; step b, solid crystal; step c, bonding; step d, injection molding and curing; step e, molding; Prepared into LED white light diode. The preparation method of the invention is reasonable, has high production efficiency and low input cost.

Description

Preparation method of LED white light diode

technical field

The invention relates to a preparation method of an LED white light diode, belonging to the technical field of semiconductor packaging.

Background technique

At present, the lead frame of the existing white light diode has a cup-shaped cover made of EMC/PPA plastic, and the transparent glue containing phosphor is applied to the cover by air pressure screw dispensing method or syringe dispensing method. Injection, so that the periphery of the light-emitting chip forms a hemispherical lens layer, and the light-emitting chip reflects light through the cup-shaped cover. The encapsulation method of the above-mentioned air pressure screw dispensing method requires extremely high investment in equipment and mold costs; while the syringe dispensing method has uneven mixing of the phosphor powder and epoxy resin, and the phosphor powder will precipitate in the epoxy resin Reduced light extraction rate, and the amount of epoxy resin poured will cause unstable quality of the products produced, and because the production process of the two methods is easily limited by a single variety, it is difficult to package this method. Conversion to mass production mode, the production efficiency is also low.

Contents of the invention

The object of the present invention is to provide a method for preparing LED white light diodes that is not only reasonable in preparation method but also low in production input cost. The method can be transformed into a mass production mode and can be mass-produced quickly to overcome the shortcomings of the prior art.

In order to achieve the above object, the technical solution of the present invention is: a preparation method of LED white light diode, said LED white light diode includes a first lead, a second lead, a blue LED chip and an epoxy resin adhesive layer containing yellow phosphor powder , the first lead has a first patch base island and a first pin integrated with each other, the second lead has a second patch base island and a second pin integrated with each other, and the blue LED chip sticks Installed on the first patch base island and electrically connected to the first patch base island, the surface of the blue LED chip is electrically connected to the second patch base island, the first patch base island, the second patch base island The base island and the blue LED chip are covered in an epoxy resin adhesive layer containing yellow phosphor; and the steps of the preparation method of the LED white light diode are:

Step a, prepare solid epoxy resin cake material containing fluorescent powder; mix the mixture formed by yellow fluorescent powder and colorless transparent epoxy resin, stir evenly at normal temperature, measure its viscosity to reach  3000~4000mPas, then put it into the oven for drying and then take it out. After the mixed material is cooled, the mixed material will be in a cake-like solid state for later use; the temperature of the oven is controlled within the range of 150~170°C, and the drying time is controlled In the range of 1.5~2.5 hours;

Step b, crystal bonding; the crystal bonding is to mount the blue LED chip on the chip base island of the lead frame through an adhesive, and then place it in an oven to dry and then take it out. The temperature of the oven is controlled at 145 In the range of ~155℃, the drying time is controlled within the range of 1.5~2.5 hours;

Step c, bonding; the bonding is to place the workpiece obtained in step b in a wire bonding machine, and use gold wires to weld the positive and negative poles of the blue LED chip to the corresponding pins of the lead frame respectively, after welding Take out the workpiece;

Step d, injection molding and curing; place the workpiece obtained in step c in the lower mold of the forming mold, cover the upper mold of the forming mold, heat the forming mold and keep its temperature within the range of 175±5°C; then Place the phosphor-containing solid epoxy resin cake prepared in step a in the injection hole of the forming mold to be softened, inject it into the forming mold under a pressure of 3-8Mpa, and cure for 2-3 minutes; then Take out the workpiece and put it into an oven with a temperature of 145~155°C to bake, so that the internal stress of the solid epoxy resin containing phosphor is fully released, so that the outer periphery of the chip base island of the lead frame and the outer periphery of the blue LED chip An epoxy resin adhesive layer containing yellow phosphor powder is formed;

Step e, forming; the forming is to remove the remaining material of the lead frame from the workpiece obtained in step d through a stamping die or cutting, so as to prepare an LED white light diode.

In the above technical solution, the weight percentage of the yellow fluorescent powder and the colorless transparent epoxy resin of the solid epoxy resin cake containing fluorescent powder used in step a is 5-8:95-92.

In the above technical solution, step b also includes pretreatment of the lead frame; in the pretreatment, the lead frame is first plated with a nickel layer, then a copper layer, and finally a silver layer, wherein the thickness of the nickel layer is controlled at >0.1um Within the range, the thickness of the copper layer is controlled within the range of 0.2~0.3um, and the thickness of the silver layer is controlled within the range of >2.5um.

In the above technical solution, there are two ways to mount the blue LED chip on the chip base island of the lead frame in step b. One way is that the positive and negative poles of the blue LED chip are on the same On the surface, the blue LED chip is mounted on the chip base island of the lead frame through insulating glue; in another way, the positive and negative poles of the blue LED chip are respectively located on both sides, and the back side of the blue LED chip Mounted on the chip base island of the lead frame through silver glue.

In the above technical solution, the thickness of the epoxy resin adhesive layer containing yellow phosphor powder formed on the periphery of the blue LED chip in step d is controlled within the range of 0.4-1mm.

The positive effects of the present invention are: due to the adoption of the above-mentioned preparation method, the epoxy resin adhesive layer containing yellow fluorescent powder of the prepared LED white light diode is prepared in advance by mixing yellow fluorescent powder and colorless transparent epoxy resin to contain yellow fluorescent powder. Phosphor powder solid epoxy resin cake, and then place the phosphor powder-containing solid epoxy resin cake in the injection hole of the molding mold to be softened, inject it into the molding mold by pressure for injection molding, and then bake and solidify to form , instead of using air pressure screw dispensing method or syringe dispensing method to inject into the cup-shaped casing in the prior art, so that the epoxy resin adhesive layer containing yellow fluorescent powder is mixed evenly, not only will not appear The phenomenon of precipitation of yellow fluorescent powder and high light reflectivity ensure the quality of the final product. The method of the invention is not only simple and reasonable, but also the cost of production input is low. The method can be transformed into a mass production mode, and can be mass-produced rapidly, thereby realizing the purpose of the present invention.

Description of drawings

Fig. 1 is the structural representation of LED white light diode of the present invention;

Fig. 2 is a schematic structural view of the forming mold of the present invention, wherein, 5 is an upper mold, 6 is a lower mold, and 7 is an injection rod.

Detailed ways

The present invention will be further described below with the given examples, but not limited thereto.

As shown in Figures 1 and 2, a method for preparing an LED white light diode, the LED white light diode includes a first lead 1, a second lead 2, a blue LED chip 3 and an epoxy resin adhesive layer 4 containing yellow phosphor powder , the first lead 1 has a first patch base island 1-1 and a first pin 1-2 integrated with each other, and the second lead 2 has a second patch base island 2-1 and a first pin integrated with each other Two pins 2-2, the blue LED chip 3 is mounted on the first SMD base island 1-1 and electrically connected to the first SMD base island 1-1, the surface of the blue LED chip 3 is connected to the first SMD base island 1-1. The second patch base island 2-1 is electrically connected, and the first patch base island 1-1, the second patch base island 2-1 and the blue LED chip 3 are wrapped in a ring containing yellow phosphor In the epoxy resin adhesive layer 4; and it: the steps of the LED white light diode preparation method are:

Step a, prepare solid epoxy resin cake material containing fluorescent powder; mix the mixture formed by yellow fluorescent powder and colorless transparent epoxy resin, stir evenly at normal temperature, measure its viscosity to reach  3000~4000mPas, then put it into the oven for drying and then take it out. After the mixed material is cooled, the mixed material will be in a cake-like solid state for later use; the temperature of the oven is controlled within the range of 150~170°C, and the drying time is controlled In the range of 1.5~2.5 hours;

Step b, solid crystal; the solid crystal is to paste the blue LED chip on the patch base island of the lead frame through an adhesive, and then put it in an oven to dry and then take it out. The temperature of the oven is controlled at 145 In the range of ~155℃, the drying time is controlled within the range of 1.5~2.5 hours;

Step c, bonding; the bonding is to place the workpiece obtained in step b in a wire bonding machine, and use gold wires to weld the positive and negative poles of the blue LED chip to the corresponding pins of the lead frame respectively, after welding Take out the workpiece;

Step d, injection molding and curing; place the workpiece obtained in step c in the lower mold of the forming mold, cover the upper mold of the forming mold, heat the forming mold and keep its temperature within the range of 175±5°C; then Place the phosphor-containing solid epoxy resin cake prepared in step a in the injection hole of the forming mold to be softened, inject it into the forming mold under a pressure of 3-8Mpa, and cure for 2-3 minutes; then Take out the workpiece and put it into an oven with a temperature of 145~155°C to bake, so that the internal stress of the solid epoxy resin containing phosphor is fully released, so that the outer periphery of the chip base island of the lead frame and the outer periphery of the blue LED chip An epoxy resin adhesive layer containing yellow phosphor powder is formed, and the epoxy resin adhesive layer containing yellow phosphor powder can also play a role in concentrating light, significantly enhancing the light intensity of the LED white light diode;

Step e, forming; the forming is to remove the remaining material of the lead frame from the workpiece obtained in step d through a stamping die or cutting, so as to prepare an LED white light diode.

The weight percent of the yellow fluorescent powder and the colorless transparent epoxy resin of the solid epoxy resin cake material containing fluorescent powder used in step a of the present invention is 5-8:95-92. Among them, the yellow fluorescent powder is preferably produced by ntematix company, and the model is YAG-04 fluorescent powder.

Step b also includes the pretreatment of the lead frame; the pretreatment is first nickel-plated on the lead frame, then copper-plated, and finally silver-plated, wherein the thickness of the nickel layer is controlled within the range of >0.1um, and the thickness of the copper layer is The thickness is controlled in the range of 0.2~0.3um, and the thickness of the silver layer is controlled in the range of >2.5um.

There are two ways to mount the blue LED chip on the chip base island of the lead frame in step b. One way is that the positive and negative poles of the blue LED chip are on the same surface, and the blue LED chip The chip is mounted on the patch base island of the lead frame through insulating glue; in another way, the positive and negative poles of the blue LED chip are respectively located on both sides, and the back of the blue LED chip is mounted on the lead frame through silver glue. lead frame on the SMD base island.

The thickness of the epoxy resin adhesive layer containing yellow phosphor powder formed on the periphery of the blue LED chip in step d is controlled within the range of 0.4-1.0 mm.

Small test results of the present invention show that adopting the packaging method of the present invention is not only simple and reasonable, but also has low production input cost, high production efficiency, and can be produced in large quantities.

Claims (5)

1. A preparation method of LED white light diode, said LED white light diode comprises a first lead (1), a second lead (2), a blue LED chip (3) and an epoxy resin adhesive layer containing yellow phosphor powder ( 4), the first lead wire (1) has the first patch base island (1-1) and the first pin (1-2) integrated with each other, and the second lead wire (2) has the first patch base island (1-2) integrated with each other Two SMD base islands (2-1) and second pins (2-2), the blue LED chip (3) is mounted on the first SMD base island (1-1) and connected to the first SMD base island (1-1) The base island (1-1) is electrically connected, the surface of the blue LED chip (3) is electrically connected to the second base island (2-1), and the first base island (1-1) , the second chip base island (2-1) and the blue LED chip (3) are coated in the epoxy resin adhesive layer (4) containing yellow phosphor powder; it is characterized in that: the preparation method of the LED white light diode The steps are: Step a, prepare solid epoxy resin cake material containing fluorescent powder; mix the mixture formed by yellow fluorescent powder and colorless transparent epoxy resin, stir evenly at normal temperature, measure its viscosity to reach  3000~4000mPas, then put it into the oven for drying and then take it out. After the mixed material is cooled, the mixed material will be in a cake-like solid state for later use; the temperature of the oven is controlled within the range of 150~170°C, and the drying time is controlled In the range of 1.5~2.5 hours; Step b, crystal bonding; the crystal bonding is to mount the blue LED chip on the chip base island of the lead frame through an adhesive, and then place it in an oven to dry and then take it out. The temperature of the oven is controlled at 145 In the range of ~155℃, the drying time is controlled within the range of 1.5~2.5 hours; Step c, bonding; the bonding is to place the workpiece obtained in step b in a wire bonding machine, and use gold wires to weld the positive and negative poles of the blue LED chip to the corresponding pins of the lead frame respectively, after welding Take out the workpiece; Step d, injection molding and curing; place the workpiece obtained in step c in the lower mold of the forming mold, cover the upper mold of the forming mold, heat the forming mold and keep its temperature within the range of 175±5°C; then Place the phosphor-containing solid epoxy resin cake prepared in step a in the injection hole of the forming mold to be softened, inject it into the forming mold under a pressure of 3-8Mpa, and cure for 2-3 minutes; then Take out the workpiece and put it into an oven with a temperature of 145~155°C to bake, so that the internal stress of the solid epoxy resin containing phosphor is fully released, so that the outer periphery of the chip base island of the lead frame and the outer periphery of the blue LED chip An epoxy resin adhesive layer containing yellow phosphor powder is formed; Step e, forming; the forming is to remove the remaining material of the lead frame from the workpiece obtained in step d through a stamping die or cutting, so as to prepare an LED white light diode. 2. The preparation method of LED white light diode according to claim 1, is characterized in that: the weight percent of the yellow fluorescent powder of the solid epoxy resin cake material containing fluorescent powder used in step a and colorless transparent epoxy resin is 5~8: 95~92. 3. The preparation method of LED white light diode according to claim 1, characterized in that: the pretreatment of the lead frame is also included in the step b; in the pretreatment, the lead frame is first plated with a nickel layer, then a copper layer, and finally plated with a copper layer. The silver layer, wherein the thickness of the nickel layer is controlled within the range of >0.1um, the thickness of the copper layer is controlled within the range of 0.2~0.3um, and the thickness of the silver layer is controlled within the range of >2.5um. 4. The preparation method of LED white light diode according to claim 1, characterized in that: the blue LED chip in step b is mounted on the patch base island of the lead frame in two ways, one way Yes, the positive and negative poles of the blue LED chip are on the same surface, and the blue LED chip is mounted on the chip base island of the lead frame through insulating glue; another way is that the positive pole of the blue LED chip The negative electrode and the negative electrode are respectively located on the two sides thereof, and the back side of the blue LED chip is mounted on the patch base island of the lead frame through silver glue. 5. The preparation method of LED white light diode according to claim 1, characterized in that: the thickness of the epoxy resin adhesive layer containing yellow phosphor powder formed on the periphery of the blue LED chip in step d is controlled within the range of 0.4-1mm Inside.