Method for reducing thickness of die bonding glue layer in LED lamp bead and LED lamp bead

Abstract

The invention discloses a method for reducing the thickness of a die bonding glue layer in an LED lamp bead and the LED lamp bead, and the method comprises the steps: providing a support, and placing the support on a die bonder support clamp; preheating the bracket to a first temperature range; dispensing die bonding glue on the bracket; pressing an LED chip to the surface, on which the solid crystal glue is dispensed, of the bracket, so that the bracket and the LED chip are bonded by the solid crystal glue; and baking and curing the solid crystal glue for bonding the bracket and the LED chip. According to the technical scheme, when the LED chip is pressed to the face, with the die bonding glue, of the support, the support is preheated firstly, and therefore after the die bonding glue is dispensed on the support, the viscosity of the die bonding glue is reduced due to the high temperature of the support, and when the swing arm on the die bonding machine table applies pressure to control the thickness of the die bonding glue, pressing is easier, and the production efficiency is improved. Therefore, the thickness of the formed solid crystal glue layer can be ensured to be consistent.

Description

Technical Field

[0001] The present invention relates to the technical field of LED packaging, and in particular to a method for reducing the thickness of a die-bonding adhesive layer in an LED lamp bead and the LED lamp bead. Background Art

[0002] When LED lamp beads are solidified, the LED chip and the bracket are bonded together by solidifying glue.

[0003] Currently, when bonding an LED chip to a bracket, the bracket to be bonded is placed on the bracket fixture of a bonding machine. A swing arm on the bonding machine then presses down on the LED chip, allowing the bonding adhesive on the bracket to bond the LED chip and the bracket together. When bonding the LED chip to the bracket, the thickness of the bonding adhesive layer is controlled by the pressure applied to the LED chip by the swing arm on the bonding machine. When dispensing glue onto the bracket, a dispensing head is used to dispense glue onto the bracket. However, when the bonding adhesive layer thickness is controlled by the swing arm on the bonding machine, the high viscosity of the bonding adhesive can result in inconsistent bonding adhesive layers, affecting heat dissipation.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for reducing the thickness of the solid crystal glue layer in LED lamp beads and LED lamp beads, so as to solve the problem in the prior art that the viscosity of the solid crystal glue is high, resulting in inconsistent thickness of the formed solid crystal glue layer, which affects the heat dissipation effect.

[0006] The technical solution adopted by the present invention to solve the technical problem is to provide a method for reducing the thickness of the die-bonding adhesive layer in LED lamp beads, comprising:

[0007] Providing a bracket, and placing the bracket on a bracket fixture of a die bonder;

[0008] preheating the support to a first temperature range;

[0009] Applying die-bonding glue to the bracket;

[0010] Pressing the LED chip onto the side of the bracket with the bonding adhesive, so that the bonding adhesive bonds the bracket and the LED chip;

[0011] The bonding adhesive for bonding the bracket and the LED chip is baked and cured.

[0012] According to a further aspect of the present invention, before the step of providing a bracket and placing the bracket on the bracket fixture of the die bonder, the step further includes:

[0013] The bracket is cleaned by using plasma, wherein the duration of cleaning the bracket by using plasma is within a first duration range.

[0014] According to a further configuration of the present invention, the first duration ranges from 60 seconds to 90 seconds.

[0015] According to a further configuration of the present invention, the first temperature range is 30°C to 70°C.

[0016] A further configuration of the present invention includes, before the step of providing a bracket and placing the bracket on the bracket fixture of the die bonder:

[0017] The bracket is dehumidified.

[0018] A further configuration of the present invention includes, before the step of applying the die-bonding adhesive to the bracket:

[0019] Fill the dispensing machine with die-bonding adhesive.

[0020] A further configuration of the present invention includes, before the step of adding the die-bonding glue into the dispensing machine:

[0021] Stabilize the die-bonding adhesive at low temperature.

[0022] A further configuration of the present invention includes, before the step of pressing the LED chip onto the side of the bracket with the bonding adhesive so that the bonding adhesive bonds the bracket to the LED chip, the step includes:

[0023] Expand the LED chip.

[0024] The present invention further provides an LED lamp bead, wherein the above-mentioned method of reducing the thickness of the die-bonding adhesive layer in the LED lamp bead is adopted during die-bonding of the LED lamp bead.

[0025] The beneficial effects of the present invention are:

[0026] The present invention discloses a method for reducing the thickness of the bonding adhesive layer in LED lamp beads and an LED lamp bead. The method comprises: providing a bracket, placing the bracket on a bracket fixture of a bonding machine; preheating the bracket to a first temperature range; applying bonding adhesive to the bracket; pressing an LED chip onto the side of the bracket where the bonding adhesive is applied, so that the bonding adhesive bonds the bracket to the LED chip; and baking and curing the bonding adhesive that bonds the bracket to the LED chip. In the technical solution of the present invention, the bracket is preheated before pressing the LED chip onto the side of the bracket where the bonding adhesive is applied. Therefore, after the bonding adhesive is applied to the bracket, the viscosity of the bonding adhesive is reduced due to the high temperature of the bracket. This makes it easier to apply pressure to control the thickness of the bonding adhesive by means of a swing arm on the bonding machine, thereby ensuring a consistent thickness of the formed bonding adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 The present invention is a flow chart of a method for reducing the thickness of a die-bonding adhesive layer in an LED lamp bead.

[0029] Figure 2 It is a diagram of the internal structure of the LED lamp bead of the present invention.

[0030] Figure 3 It is a schematic diagram of the structure of a crystal bonding machine bracket clamp equipped with a heating device in one embodiment of the present invention.

[0031] Figure 4 This is the experimental result diagram using water as the test object before the bracket is cleaned with plasma.

[0032] Figure 5 This figure shows the experimental results after plasma cleaning of the bracket using water as the test object.

[0033] Reference numerals in the accompanying drawings: 100 , bracket; 200 , bracket fixture of the crystal bonding machine; 300 , heating device. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution and do not indicate that the devices or components referred to must have specific directions. Therefore, they should not be understood as limiting the present invention.

[0035] like Figure 2 The figure shows the internal structure of an LED (Light Emitting Diode). Figure 2Where a represents the welding layer, b represents the filled sealing resin glue, c represents the wire, d represents the LED chip, e represents the resin filled with yellow phosphor, f represents the packaging substrate, g represents the heat flow path when the LED lamp bead dissipates heat, h represents the insulating film layer, and i represents the aluminum substrate; wherein, in the LED lamp bead, after the LED chip heats up, the heat of the LED chip is conducted downward through the solid crystal glue layer at the bottom of the LED lamp bead. wherein, when the thickness of the solid crystal glue layer is too thick, the thermal resistance of the LED lamp bead will be high, and the heat of the LED chip cannot be conducted away, thereby causing the LED chip to continue to be high temperature, affecting the service life of the LED lamp bead. wherein, the thermal resistance of the LED lamp bead is equal to the thermal conductive thickness of the solid crystal glue layer divided by (the thermal conductive cross-sectional area of ​​the solid crystal glue layer × the thermal conductivity coefficient of the solid crystal glue layer).

[0036] Currently, when forming the adhesive layer in LED lamp beads, the bracket to be bonded is placed on the bracket fixture of the bonding machine. The swing arm of the bonding machine presses down on the LED chip, allowing the adhesive on the bracket to bond the LED chip and the bracket together. When the LED chip and the bracket are bonded, the pressure applied to the LED chip by the swing arm of the bonding machine controls the thickness of the adhesive layer. When dispensing glue on the bracket, a dispensing head is used to apply glue to the bracket. However, when the thickness of the adhesive layer is controlled by the swing arm of the bonding machine, due to the high viscosity of the adhesive, the thickness of the formed adhesive layer is inconsistent, affecting the heat dissipation effect.

[0037] Based on the above problems, Figure 1 As shown, the present invention provides a method for reducing the thickness of the die-bonding adhesive layer in LED lamp beads, which may include the following steps:

[0038] S5. Provide a bracket and place the bracket on the bracket fixture of the die bonder;

[0039] S6, preheating the bracket to a first temperature range;

[0040] S7, apply die-bonding glue to the bracket;

[0041] S8, pressing the LED chip onto the side of the bracket with the bonding adhesive, so that the bonding adhesive bonds the bracket to the LED chip;

[0042] S9, baking and curing the die-bonding adhesive bonding the bracket and the LED chip.

[0043] Specifically, during die bonding, a bracket is placed on a bracket fixture of a die bonding machine and the bracket is preheated. Figure 3As shown, when preheating the bracket, a preheating device can be added to the base of the bracket fixture of the crystal bonder (a fixture for placing the bracket). For example, a heating wire can be added to the base of the bracket fixture of the crystal bonder. The bracket is preheated by the preheating device so that the bracket is within the first temperature range of the preset value. Afterwards, the dispensing head of the dispensing machine dispenses the crystal glue on the bracket. After the crystal glue is dispensed on the bracket, the swing arm of the crystal bonder table sucks the LED chip from the blue film, transports it to the top of the bracket, and presses the LED chip to the side of the bracket with the crystal glue, so that the crystal glue bonds the bracket to the LED chip. After the bracket and the LED chip are bonded, the bracket with the LED chip is placed in an oven for baking and curing to form a crystal glue layer.

[0044] In this embodiment, when the LED chip is pressed onto the side of the bracket with the bonding glue, the bracket is preheated first. Therefore, after the bonding glue is applied to the bracket, the viscosity of the bonding glue is reduced due to the high temperature of the bracket. Therefore, when the thickness of the bonding glue is controlled by applying pressure through the swing arm on the bonding machine, it is easier to press down, so that the thickness of the formed bonding glue layer can be guaranteed to be consistent.

[0045] In some embodiments, as Figure 1 As shown, a bracket is provided, and before the step of placing the bracket on the bracket fixture of the die bonder, the step further includes:

[0046] S4. Cleaning the bracket using plasma, wherein the duration of cleaning the bracket using plasma is within a first duration range.

[0047] In this step, plasma is used to clean the bracket. After plasma cleaning, the bonding glue will be diffused on the bracket, making it easier to press down when applying pressure through the swing arm on the bonding machine to control the thickness of the bonding glue, thereby thinning the thickness of the formed bonding glue layer.

[0048] like Figure 4 The figure shows the state of water droplets on the bracket when the bracket is not cleaned by plasma. Figure 4 It can be seen that the water droplets are in a non-diffusion state (the water drop angle is large, and the water drop angle refers to the angle between the tangent of the water drop arc at the point where the water drop contacts the plane and the plane. A large water drop angle means that the water droplets have not diffused on the surface of the bracket). In this state, it means that after the solid crystal glue is applied to the bracket, the solid crystal glue is also in a non-diffusion state on the bracket. When the solid crystal glue is in a non-diffusion state, the thickness of the formed solid crystal glue layer is relatively thick, which also affects the heat dissipation effect.

[0049] like Figure 5 As shown, the state of water droplets on the bracket after the bracket is cleaned by plasma. Figure 5It can be seen that the water droplets are in a diffused state (the water drop angle is small, which means that the water droplets are diffused on the surface of the bracket). In this state, after the solid crystal glue is applied to the bracket, the solid crystal glue is in a diffused state on the bracket. When the solid crystal glue is in a diffused state, the thickness of the formed solid crystal glue layer becomes thinner and the heat dissipation effect becomes better.

[0050] It should be noted that when using plasma to clean the bracket, because plasma cleaning is required after welding wires and gluing on the bracket, the number and time of plasma cleaning will affect the brightness of the bracket if it is too long. When the plasma cleaning time is short, the cleaning effect is poor and it cannot diffuse the solid crystal glue on the bracket. Therefore, when using plasma to clean the bracket, you need to pay attention to the cleaning time.

[0051] Furthermore, the first duration ranges from 60 seconds to 90 seconds.

[0052] Specifically, when plasma cleaning the bracket, the cleaning time can be but not limited to 60 seconds, 65 seconds, 68 seconds, 70 seconds, 80 seconds, 90 seconds, etc. Those skilled in the art can determine the time for plasma cleaning the bracket according to actual needs.

[0053] In some embodiments, the first temperature range is 30°C to 70°C.

[0054] Specifically, when preheating the bracket, the bracket can be preheated to but not limited to 30°C, 40°C, 45°C, 48°C, 50°C, 57°C, 60°C, 70°C, etc. Those skilled in the art can determine the preheating temperature of the bracket according to the specific situation.

[0055] It should be noted that when the bracket is preheated, if the preheating temperature is less than 30°C, the viscosity of the die-bonding adhesive on the bracket does not change. If the preheating temperature is greater than 70°C, the die-bonding adhesive on the bracket will solidify.

[0056] In some embodiments, as Figure 1 As shown, before providing a bracket and placing the bracket on the bracket fixture of the die bonder, the steps include:

[0057] S3. Dehumidify the bracket.

[0058] In this step, an oven may be used to dehumidify the bracket.

[0059] In some embodiments, as Figure 1 As shown, before the step of applying the die-bonding adhesive to the bracket, the following steps are included:

[0060] S2. Fill the dispensing machine with bonding glue.

[0061] In this step, a dispensing machine is used to dispense the bonding adhesive onto the bracket, wherein the dispensing machine is filled with the bonding adhesive before the bonding adhesive is dispensed onto the bracket.

[0062] In some embodiments, as Figure 1 As shown, the steps before filling the die-bonding adhesive in the dispensing machine include:

[0063] S1. Stabilize the die-bonding adhesive at low temperature.

[0064] The bonding adhesive is stored in a refrigerator or freezer, but when it is used, the ambient temperature is higher than the temperature of the bonding adhesive during refrigeration or freezing. If it is used directly, the performance of the bonding adhesive will be reduced or even poorly cured. Therefore, when the bonding adhesive is used, the temperature of the bonding adhesive needs to be stabilized so that the temperature of the bonding adhesive is close to the ambient temperature of use to avoid the formation of condensation water and ensure the quality and viscosity of the bonding adhesive.

[0065] In some embodiments, as Figure 1 As shown, before pressing the LED chip onto the side of the bracket with the bonding adhesive and allowing the bonding adhesive to bond the bracket to the LED chip, the steps include:

[0066] S0. Expand the LED chip.

[0067] Specifically, during crystal bonding, the LED chips are tightly arranged on the blue film. When the LED chips are transported by the swing arm of the crystal bonding machine, the LED chips on the blue film need to be expanded first to ensure that the spacing between the LED chips can meet the spacing between the LED chips when the LED chips are transported by the swing arm of the crystal bonding machine.

[0068] In some embodiments, the present invention further provides an LED lamp bead, wherein the method for reducing the thickness of the die-bonding adhesive layer in the LED lamp bead is used when the LED lamp bead is die-bonded, wherein the method may include the steps of:

[0069] S5. Provide a bracket and place the bracket on the bracket fixture of the die bonder;

[0070] S6, preheating the bracket to a first temperature range;

[0071] S7, apply die-bonding glue to the bracket;

[0072] S8, pressing the LED chip onto the side of the bracket with the bonding adhesive, so that the bonding adhesive bonds the bracket to the LED chip;

[0073] S9, baking and curing the die-bonding adhesive bonding the bracket and the LED chip.

[0074] Specifically, during the crystal bonding process, a bracket is placed on the bracket fixture of the crystal bonding machine and preheated. When preheating the bracket, a preheating device can be added to the base of the bracket fixture of the crystal bonding machine (a fixture for placing the bracket). The preheating device preheats the bracket so that the bracket is within a preset first temperature range. Subsequently, the dispensing head of the dispensing machine dispenses crystal bonding glue onto the bracket. After the crystal bonding glue is dispensed onto the bracket, the swing arm of the crystal bonding machine platform sucks the LED chip from the blue film, transports it to the top of the bracket, and presses the LED chip onto the side of the bracket with the crystal bonding glue, so that the crystal bonding glue bonds the bracket to the LED chip. After the bracket and the LED chip are bonded, the bracket with the LED chip bonded is placed in an oven for baking and curing to form a crystal bonding glue layer.

[0075] In this embodiment, when the LED chip is pressed onto the side of the bracket with the bonding glue, the bracket is preheated first. Therefore, after the bonding glue is applied to the bracket, the viscosity of the bonding glue is reduced due to the high temperature of the bracket. Therefore, when the thickness of the bonding glue is controlled by applying pressure through the swing arm on the bonding machine, it is easier to press down, so that the thickness of the formed bonding glue layer can be guaranteed to be consistent.

[0076] In some embodiments, providing a bracket, and before placing the bracket on a bracket fixture of a die bonder, further comprising:

[0077] S4, using plasma to clean the bracket, wherein the duration of using plasma to clean the bracket is within the first duration range. The details are as described in the embodiment of the above method for reducing the thickness of the die-bonding adhesive layer in the LED lamp bead, and will not be repeated here.

[0078] Furthermore, the first duration ranges from 60 seconds to 90 seconds.

[0079] Specifically, when plasma cleaning the bracket, the cleaning time can be but not limited to 60 seconds, 65 seconds, 68 seconds, 70 seconds, 80 seconds, 90 seconds, etc. Those skilled in the art can determine the time for plasma cleaning the bracket according to actual needs.

[0080] In some embodiments, the first temperature range is 30°C to 70°C.

[0081] Specifically, when preheating the bracket, the bracket can be preheated to but not limited to 30°C, 40°C, 45°C, 48°C, 50°C, 57°C, 60°C, 70°C, etc. Those skilled in the art can determine the preheating temperature of the bracket according to the specific situation.

[0082] It should be noted that when the bracket is preheated, if the preheating temperature is less than 30°C, the viscosity of the die-bonding adhesive on the bracket does not change. If the preheating temperature is greater than 70°C, the die-bonding adhesive on the bracket will solidify.

[0083] In some embodiments, before providing a bracket and placing the bracket on a bracket fixture of a die bonder, the method includes:

[0084] S3, dehumidifying the bracket. The details are as described in the above embodiment of a method for reducing the thickness of the die-bonding adhesive layer in the LED lamp bead, and will not be repeated here.

[0085] In some embodiments, before applying die-bonding adhesive to the bracket, the method includes:

[0086] S2, filling the dispensing machine with bonding adhesive. The details are as described in the above embodiment of a method for reducing the thickness of the bonding adhesive layer in LED lamp beads, and will not be repeated here.

[0087] In some embodiments, before the step of adding die-bonding adhesive to the dispensing machine, the method includes:

[0088] S1. Stabilizing the die-bonding adhesive at low temperature. The details are as described in the above embodiment of a method for reducing the thickness of the die-bonding adhesive layer in LED lamp beads, and will not be repeated here.

[0089] In some embodiments, before pressing the LED chip onto the side of the bracket with the bonding adhesive applied thereon so that the bonding adhesive bonds the bracket to the LED chip, the following steps are included:

[0090] S0, expanding the LED chip. The details are as described in the above embodiment of a method for reducing the thickness of the die-bonding adhesive layer in the LED lamp bead, and will not be repeated here.

[0091] In summary, the present invention provides a method for reducing the thickness of the die-bonding adhesive layer in LED lamp beads and LED lamp beads, which have the following beneficial effects:

[0092] When pressing the LED chip onto the side of the bracket with the bonding glue, the bracket is preheated first. Therefore, after the bonding glue is applied to the bracket, the viscosity of the bonding glue is reduced due to the high temperature of the bracket. Therefore, when the swing arm on the bonding machine applies pressure to control the thickness of the bonding glue, it is easier to press down, so that the thickness of the formed bonding glue layer can be guaranteed to be consistent.

[0093] It is understandable that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A method for reducing the thickness of a solid crystal adhesive layer in an LED lamp bead, characterized in that: include: Providing a bracket, and placing the bracket on a bracket fixture of a die bonder; preheating the support to a first temperature range; Applying a bonding adhesive to the bracket; Pressing the LED chip onto the side of the bracket with the bonding adhesive, so that the bonding adhesive bonds the bracket and the LED chip; The bonding adhesive for bonding the bracket and the LED chip is baked and cured.

2. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 1, characterized in that: Before the step of providing a bracket and placing the bracket on the bracket fixture of the die bonder, the step further includes: The support is cleaned by using plasma, wherein the duration of cleaning the support by using plasma is within a first duration range.

3. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 2, characterized in that: The first duration ranges from 60 seconds to 90 seconds.

4. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 1, characterized in that: The first temperature range is 30°C to 70°C.

5. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 1, characterized in that: Before the step of providing a bracket and placing the bracket on the bracket fixture of the die bonder, the step includes: The support is dehumidified.

6. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 1, characterized in that: Before the step of applying the bonding adhesive to the bracket, the method includes: Fill the dispensing machine with die-bonding glue.

7. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 6, characterized in that: Before the step of filling the die-bonding glue in the glue dispensing machine, the method includes: Stabilize the die-bonding adhesive at low temperature.

8. The method for reducing the thickness of the bonding layer in LED lamp beads according to claim 1, characterized in that: Before the step of pressing the LED chip onto the side of the bracket with the bonding adhesive so that the bonding adhesive bonds the bracket to the LED chip, the step includes: Expand the LED chip.

9. An LED lamp bead, characterized in that: When the LED lamp bead is being bonded, the method for reducing the thickness of the bonding adhesive layer in the LED lamp bead as claimed in any one of claims 1 to 8 is adopted.

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