A flip-chip LED chip structure and manufacturing method thereof

Abstract

The present invention provides a flip-chip LED chip structure, comprising an LED bracket, the LED bracket comprising a bracket positive electrode and a bracket negative electrode; an LED chip flipped in a bowl cup of the LED bracket; and insulating reflective adhesive formed in the bowl cup of the LED bracket to cover the LED chip. The electrode areas of the bracket positive electrode and the bracket negative electrode where the LED chip is placed are higher than other areas of the bracket positive electrode and the bracket negative electrode, and the other areas include areas of the bracket positive electrode and the bracket negative electrode except for the electrode areas where the LED chip is placed. Compared with the flat-bottom structure of the electrode areas of the existing LED bracket, the insulating reflective adhesive can easily flow into the bottom of the LED chip through the raised electrode areas. The insulating reflective adhesive covers the LED chip on all sides, thereby avoiding the problem of micro-short circuit or even complete short circuit in the product, and also avoiding the problem of dark cracks or damage caused by thermal expansion of air at the bottom of the chip, thereby improving the reliability of the product.

Description

Technical Field

[0001] The present invention relates to the application field of LEDs, and in particular to a flip-chip LED chip structure and a manufacturing method thereof. Background Art

[0002] Today, LEDs are widely used in LCD backlighting and lighting applications. As their applications expand, market demands for them are also increasing. LED performance varies significantly depending on their structure, and optimizing their structure can improve their performance.

[0003] Currently, based on the structure of flip-chip LED chips, see Figure 1 , including LED bracket 101, flip-chip LED chip 102, white glue 103, specifically, first use solder 104 to fix the flip-chip LED chip 102 in the bowl of LED bracket 101, and fill the gap between LED chip 102 and LED bracket 101 with white glue 103, based on Figure 1 In the LED structure shown, since the solder thickness is generally only 10-25um, the height between the bottom of the LED chip and the bottom of the LED bracket is 10-25um, and the height gap between the LED chip and the LED bracket is small, when filling with white glue, the height difference between the positive and negative solders at the bottom of the LED chip due to the white glue flowing from the LED bracket is small, making it impossible for the white glue to flow between the positive and negative solders at the bottom of the LED chip, eventually causing a micro short circuit or even a complete short circuit in the product; at the same time, since there is no white glue at the bottom of the LED chip, when the product is used, the air at the bottom of the LED chip expands due to heat, which can easily cause dark cracks or damage to the LED chip. Summary of the Invention

[0004] The present invention provides a flip-chip LED chip structure and a manufacturing method thereof, which mainly solves the technical problem that: in the existing flip-chip LED chip structure, white glue cannot flow between the positive and negative solders at the bottom of the LED chip, resulting in the migration of solder between the positive and negative poles of the LED chip, resulting in a micro short circuit or even a complete short circuit in the product. At the same time, the air at the bottom of the LED chip expands due to heat when the product is used, which easily causes dark cracks or damage to the LED chip.

[0005] To solve the above technical problems, the present invention provides a flip-chip LED chip structure, comprising:

[0006] An LED bracket, the LED bracket comprising a bracket positive electrode, a bracket negative electrode; an LED chip flipped inside the LED bracket bowl; and an insulating reflective adhesive formed inside the LED bracket bowl to cover the LED chip;

[0007] The electrode area of the bracket positive electrode and the bracket negative electrode where the LED chip is placed is higher than other areas of the bracket positive electrode and the bracket negative electrode, and the other areas include the areas of the bracket positive electrode and the bracket negative electrode except the electrode area where the LED chip is placed.

[0008] Optionally, the insulating reflective adhesive fills the insulating gap between the positive electrode pin and the negative electrode pin at the bottom of the LED chip.

[0009] Optionally, the bottom of the LED chip has a positive pin and a negative pin, and the positive pin and the negative pin are electrically connected to the positive pole and the negative pole of the bracket respectively through solder provided on the electrode area, and the insulating reflective glue fills the insulating gap between the solders.

[0010] Optionally, the electrode area where the LED chip is placed is larger than the LED chip.

[0011] Optionally, the area of the solder is smaller than the area of the electrode region.

[0012] Furthermore, the present invention also provides a method for manufacturing the above-mentioned flip-chip LED structure, the manufacturing method comprising:

[0013] Step S1: Designing and manufacturing an LED bracket, wherein the electrode area of the LED bracket where the LED chip is placed is higher than other areas of the LED bracket electrode;

[0014] Step S2: printing solder on the raised electrode area;

[0015] Step S3: flip-mounting the LED chip on the solder;

[0016] Step S4: dispensing glue, after the insulating reflective glue flows into the bottom of the LED chip, curing the insulating reflective glue.

[0017] Optionally, in step S2, the solder is printed on the electrode area through a 3D steel mesh, and the opening size of the 3D steel mesh is smaller than the area of the electrode area.

[0018] Optionally, in step S3, when the solder comprises silver paste, the LED chip is placed on the solder and baked at a constant temperature of 170° C. for 1 hour;

[0019] When the solder comprises solder paste or flux, the LED chip is placed on the solder and reflowed for 30 seconds in a nitrogen environment at a maximum furnace temperature of 290°C.

[0020] Optionally, after step S3 and before step S4, the method further includes sticking a fluorescent sheet on the LED chip using a high-temperature resistant silicone resin and baking the fluorescent sheet at 150° C. for 3-4 hours.

[0021] Optionally, in step S4, the insulating reflective glue includes white glue, and a layer of white glue is sprayed around the fluorescent sheet and the LED bracket using a dispensing device, and the flip-chip LED structure is placed in an environment at 43°C for 1-2 hours to allow the white glue to flow into the bottom of the LED chip; or, the white glue is centrifugally precipitated by a centrifuge to allow the white glue to flow into the bottom of the LED chip. When the white glue completely fills the bottom of the LED chip, the flip-chip LED structure is placed in an environment at 150°C and baked for 3-4 hours to cure the white glue.

[0022] Beneficial effects

[0023] The present invention provides a flip-chip LED chip structure, comprising an LED bracket, the LED bracket including a bracket positive electrode and a bracket negative electrode; an LED chip flip-chip mounted in a bowl of the LED bracket; and insulating reflective adhesive formed in the bowl of the LED bracket to cover the LED chip. The electrode areas of the bracket positive electrode and the bracket negative electrode, where the LED chip is placed, are higher than other areas of the bracket positive electrode and the bracket negative electrode, where the other areas include areas of the bracket positive electrode and the bracket negative electrode excluding the electrode areas where the LED chip is placed. The flip-chip LED chip structure provided by the present invention has at least the following advantages:

[0024] 1. The flip-chip LED chip structure provided by the present invention has an electrode area where the LED chip is placed that is higher than the other areas of the bracket's positive and negative electrodes. Compared to the existing LED bracket structure with a flat bottom electrode area, the raised electrode area allows the insulating reflective adhesive to easily flow into the bottom of the LED chip.

[0025] 2. The flip-chip LED chip structure provided by the present invention has an insulating reflective adhesive coating the LED chip, so that the bottom and surrounding areas of the LED chip are completely covered by the insulating reflective adhesive, thereby preventing the product from having micro short circuits or even complete short circuits due to solder overflow or migration. It also avoids dark cracks or damage caused by thermal expansion of the air at the bottom of the chip, thereby improving product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of an existing flip-chip LED chip;

[0027] Figure 2 A schematic structural diagram of a flip-chip LED chip structure provided in Example 1 of the present invention;

[0028] Figure 3 Schematic diagram of the electrode area of the positive electrode and the negative electrode of the bracket provided in Example 1 of the present invention Figure 1 ;

[0029] Figure 4Schematic diagram of the electrode area of the positive electrode and the negative electrode of the bracket provided in Example 1 of the present invention Figure 2 ;

[0030] Figure 5 Schematic diagram of the embodiment 1 of the present invention, in which the electrode areas of the positive electrode and the negative electrode of the bracket are larger than the chip area;

[0031] Figure 6 A first detailed structural diagram of a flip-chip LED chip structure provided in the first embodiment of the present invention;

[0032] Figure 7 A second detailed structural diagram of the flip-chip LED chip structure provided in the first embodiment of the present invention;

[0033] Figure 8 A third detailed structural diagram of the flip-chip LED chip structure provided in the first embodiment of the present invention;

[0034] Figure 9 A flow chart of a method for manufacturing a flip-chip structure provided in the second embodiment of the present invention;

[0035] Figure 10 A schematic diagram of an LED bracket provided in Example 2 of the present invention;

[0036] Figure 11 Schematic diagram of printed solder provided in Example 2 of the present invention Figure 1 ;

[0037] Figure 12 Schematic diagram of printed solder provided in Example 2 of the present invention Figure 2 ;

[0038] Figure 13 A schematic diagram of a flip-chip LED chip provided in the second embodiment of the present invention;

[0039] Figure 14 A schematic diagram of attaching a fluorescent sheet according to the second embodiment of the present invention;

[0040] Figure 15 A schematic diagram of dispensing provided in Example 2 of the present invention;

[0041] Figure 16 This is a structural diagram of a flip-chip LED chip structure provided by the third embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the content of the present invention easier to understand, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1:

[0044] The existing flip-chip LED chip is first fixed in the bowl of the LED bracket with solder, and white glue is filled into the gap between the LED chip and the bracket. Based on the existing LED structure, the white glue cannot flow between the positive and negative solders at the bottom of the LED chip. After long-term use, it will cause the solder between the positive and negative poles of the LED chip to migrate (such as silver migration and solder paste drawing), and eventually cause the product to have a micro short circuit or even a complete short circuit. At the same time, since there is no white glue at the bottom of the LED chip, when the product is used, the air at the bottom of the LED chip expands due to heat, which can easily cause dark cracks or damage to the LED chip.

[0045] In order to solve the above problems, this embodiment provides a flip-chip LED chip structure. Figure 2 , the flip-chip LED chip structure includes:

[0046] LED bracket 201, LED bracket 201 includes a bracket positive pole 2011, a bracket negative pole 2012; an LED chip 202 is inverted in the bowl of LED bracket 201; an insulating reflective adhesive 203 is formed in the bowl of LED bracket 201 to cover the LED chip 202 on all sides; wherein the insulating reflective adhesive 203 covers the LED chip 202, including the bottom and surrounding of the LED chip 202 are covered by the insulating reflective adhesive 203; specifically, the LED chip 202 has a positive pin and a negative pin, and the insulating reflective adhesive 203 covers the surrounding of the LED chip 202 and between the positive pin and the negative pin at the bottom of the LED chip 202.

[0047] In this embodiment, if Figure 3 As shown, the electrode area 201a (the area corresponding to the dotted box in the figure) where the LED chip 202 is placed in the positive electrode 2011 and the negative electrode 2012 of the bracket is higher than the other areas 201b of the positive electrode 2011 and the negative electrode 2012 of the bracket. The other areas 201b include the areas of the positive electrode 2011 and the negative electrode 2012 of the bracket except the electrode area 201a where the LED chip 202 is placed; that is, part of the area in the bracket electrode of the flip-chip LED chip structure in this embodiment is raised, so that the electrode area 201a where the LED chip 202 is placed is the raised part.

[0048] In this embodiment, the LED bracket 201 can be an integrally formed structure, that is, the electrode region 201a of the bracket positive electrode 2011 and the bracket negative electrode 2012 and the other region 201b are formed as a whole. Figure 3In some embodiments, the electrode material corresponding to the bracket electrode 201a can be superimposed on the partial area of the bracket positive electrode 2011 and the bracket negative electrode 2012 to obtain the electrode area 201a. Of course, the electrode material can be completely consistent with the material of the bracket electrode, or it can be a conductive metal material, such as Figure 4 As shown, the electrode material 301 is superimposed on the bracket positive electrode 2011 and the bracket negative electrode 2012 to obtain a raised electrode area.

[0049] It can be understood that the electrode region 201a in this embodiment includes a positive electrode region and a negative electrode region. Of course, the height and shape of the positive electrode region and the negative electrode region are the same and they are symmetrical structures. Preferably, the height of the positive electrode region and the negative electrode region is 30-50um, that is, the electrode region 201a is 30-50um higher than the other regions 201b. When the LED chip 202 passes through the solder set on the electrode region 201a, since the solder thickness is generally only 10-25um, the distance between the LED chip 202 and the bottom surface of the LED bracket 201 is raised to 40-75um. When the insulating reflective glue is filled around the LED bracket 201, since the height difference between the LED bracket 201 and the bottom of the LED chip 202 is large, the insulating reflective glue naturally flows into the bottom of the LED chip 202 by utilizing the height difference. Then, when the LED chip 202 is manufactured, the insulating reflective glue 203 can flow from the periphery of the LED chip 202 to the bottom of the LED chip 202.

[0050] In this embodiment, the shape of the electrode region 201a can be a rectangle, a square, or other shapes, such as Figure 3 As shown, the electrode region 201a is rectangular in shape. It is worth noting that the area of the electrode region 201a is larger than the area of the LED chip 202 to avoid the LED chip 202 not being able to fully contact the LED bracket 201 electrode when placed. Figure 5 As shown, the area of the electrode region 201 a where the LED chip is placed is slightly larger than the area of the LED chip 202 .

[0051] It should be understood that if Figure 6As shown, in this embodiment, the bottom of the LED chip 202 includes a positive pin and a negative pin (not shown in the figure), and the positive pin and the negative pin are electrically connected to the positive electrode 2011 of the bracket and the negative electrode 2012 of the bracket respectively through the solder 204 set on the electrode area 201a; wherein the thickness of the solder 204 is included in 10-25um, so as to avoid the excessive thickness of the solder 204 affecting the heat dissipation of the LED chip 202. In this embodiment, the solder 204 includes but is not limited to silver glue, solder paste, and flux. Preferably, the area of the solder 204 is smaller than the area of the electrode area 201a. Of course, the area of the solder 204 can be smaller than the area of the LED chip 202, or it can be the same as the area of the LED chip 202, so as to avoid the problem of excessive solder 204 and the migration of the solder 204. Figure 6 As shown, the area of the electrode region 201a is slightly larger than the area of the LED chip 202, and the area of the solder 204 is the same as the area of the LED chip 202. In this embodiment, an insulating reflective adhesive 203 is provided between the positive and negative pins of the LED chip 204, and the positive and negative pins are bonded to the solder 204. Therefore, based on the bottom surface of the bracket 201 as the height starting surface, the height of the insulating reflective adhesive 203 between the positive and negative pins is equal to the height of the solder 204, and the width of the insulating reflective adhesive 203 layer can be less than or equal to the width of the gap between the solders 204, as shown in FIG. Figure 6 As shown, insulating reflective adhesive 203 is provided between the solders 204, and the height of the insulating reflective adhesive 203 is aligned with the height of the solders 204. The width of the insulating reflective adhesive 203 is the same as the width between the solders. The insulating reflective adhesive 203 is also provided in the gap between the positive electrode 2011 and the negative electrode 2012 of the LED bracket 201. The insulating reflective adhesive 203 on the positive and negative pins at the bottom of the LED chip 202 reliably isolates the positive and negative pins of the LED chip 202, preventing short circuits between the positive and negative pins. It also prevents air from entering the bottom of the LED chip 202, causing dark cracks or damage to the chip. It also reflects light that reaches the bottom of the LED chip 202, improving the light output of the LED chip 202 and preventing light leakage from the bottom of the LED chip 202.

[0052] It is worth noting that Figure 7 As shown, the flip-chip LED chip structure provided in this embodiment also includes a fluorescent sheet 205 formed in the bowl of the LED bracket 201 to cover the LED chip 202. The fluorescent sheet 205 is located directly above the LED chip 202. The size of the fluorescent sheet 205 is greater than or equal to the size of the LED chip 202. The size of the fluorescent sheet 205 is slightly larger than the size of the flip-chip to avoid blue light leakage. The material of the fluorescent sheet 205 includes but is not limited to silicone, ceramic or glass, and can be flexibly selected according to the power size and reliability of the product. In this embodiment, as Figure 7 As shown, the height of the fluorescent sheet 205 is the same as the height of the insulating reflective adhesive 203, that is, the surrounding of the fluorescent sheet 205 is also covered by the insulating reflective adhesive 203. Preferably, the insulating reflective adhesive 203 has a certain curvature, and the height of the insulating reflective adhesive 203 in contact with the fluorescent sheet 205 is the same as the height of the fluorescent sheet 205, and the height of the insulating reflective adhesive 203 in contact with the LED bracket 201 is the same as the height of the bowl of the LED bracket 201. In some embodiments, such as Figure 8 As shown, the insulating reflective adhesive 203 may also be a horizontal structure, that is, any height of the insulating reflective adhesive 203 in the horizontal direction is the same as the height of the fluorescent sheet 205; it should be noted that in order to prevent the fluorescent sheet 205 from being damaged during use or transportation of the product, the height of the fluorescent sheet 205 in this embodiment is 30-60 μm lower than the horizontal plane of the bowl rim of the LED bracket 201.

[0053] In this embodiment, the insulating reflective glue 203 may be any colloid having insulating and reflective properties. In practical applications, the insulating reflective glue 203 may be white glue. The white glue may be silica gel (or methyl silicone resin or phenyl silicone resin) containing titanium dioxide TiO2, sulfur dioxide SiO2, or aluminum oxide Al2O3, wherein the particle size of TiO2, SiO2, and Al2O3 is within a range of 20-40 μm.

[0054] This embodiment provides a flip-chip LED chip structure, including an LED bracket having an LED bracket positive electrode and a bracket negative electrode, an LED chip flipped in a bowl of the LED bracket, and insulating reflective adhesive covering the LED chip. The electrode area where the LED chip is placed is higher than other areas of the bracket positive electrode and the bracket negative electrode. Compared with the flat-bottom structure of the electrode area of the existing LED bracket, the raised electrode area allows the insulating reflective adhesive to easily flow into the bottom of the LED chip. As a result, the bottom and surrounding areas of the LED chip are completely covered by the insulating reflective adhesive, avoiding problems such as solder overflow and migration that may cause micro-short circuits or even complete short circuits in the product. At the same time, it also avoids problems such as dark cracks or damage caused by thermal expansion of air at the bottom of the chip, thereby improving product reliability.

[0055] Example 2:

[0056] This embodiment provides a method for manufacturing the flip chip LED structure in the first embodiment. Figure 9 As shown, the production method includes:

[0057] Step S901: Design and manufacture an LED bracket, wherein the electrode area of the LED bracket where the LED chip is placed is higher than other electrode areas of the LED bracket;

[0058] Step S902: printing solder on the raised electrode area;

[0059] Step S903: flip-chipping the LED chip onto the solder;

[0060] Step S904: dispensing glue. After the insulating reflective glue flows to the bottom of the LED chip, the insulating reflective glue is cured.

[0061] In this embodiment, the LED bracket is redesigned to elevate the electrode area where the LED chip is placed. Specifically, the LED bracket includes a positive electrode and a negative electrode. The electrode area of the positive and negative electrodes where the LED chip is placed is higher than the remaining areas of the positive and negative electrodes. The remaining areas include the areas of the positive and negative electrodes excluding the electrode area where the LED chip is placed. The electrode area 201a is 30-50 μm higher than the remaining area 201b. This electrode area is larger than the area of the LED chip, preventing the chip from completely contacting the bracket electrode when placed, as shown in Figure 10.

[0062] In this embodiment, in step S902, solder 1201 is printed on the electrode area through the 3D steel mesh 1101, wherein the solder 1201 includes but is not limited to silver glue, solder paste, and flux; the opening size of the 3D steel mesh 1101 is smaller than the area of the electrode area to prevent the solder 1201 from excessively migrating out of the raised electrode area, such as Figure 11 、 12 shown.

[0063] In this embodiment, in step S903, the specific process is different depending on the material of the solder 1201. When the solder 1201 includes silver glue, the LED chip 1301 is placed on the solder 1201 and baked at a constant temperature of 170°C for 1 hour; when the solder 1201 includes solder paste or flux, the LED chip 1301 is placed on the solder 1201 and reflowed in a nitrogen environment at a maximum furnace temperature of 290°C for 30 seconds. The purpose of reflowing in a nitrogen environment is to prevent the metal particles in the solder 1201 from being oxidized; the solder 1201 is melted by baking or reflowing and is fully combined with the LED chip 1301 and the LED bracket, such as Figure 13 shown.

[0064] It is worth noting that when the flip-chip LED structure includes a fluorescent sheet 1401, after step S903 and before step S904, it also includes attaching the fluorescent sheet 1401 to the LED chip 1301. Specifically, the fluorescent sheet 1401 is attached to the LED chip 1301 using high-temperature resistant silicone resin and baked at 150°C for 3-4 hours to completely combine the fluorescent sheet 1401 with the LED chip 1301. The fluorescent sheet 1401 can be made of silicone, ceramic or glass, and is selected according to the power and reliability requirements of the product. It is understandable that the size of the fluorescent sheet 1401 is slightly larger than the size of the flip chip to avoid blue light leakage. After the fluorescent sheet 1401 is attached, its height is slightly lower than the LED bracket bowl by 30-60um to avoid damage to the fluorescent sheet 1401 during use or transportation. Figure 14 shown.

[0065] It should be noted that, in this embodiment, in step S904, the insulating reflective glue includes white glue 1502, and a layer of white glue 1502 is sprayed around the fluorescent sheet 1401 and the LED bracket using a dispensing device 1501. The white glue 1502 may be a silica gel (or methyl silicone resin or phenyl silicone resin) of TiO2, SiO2, or Al2O3, and the particle size of the TiO2, SiO2, or Al2O3 is between 20 and 40 μm. The thickness of the white glue 1502 is level with the height of the fluorescent sheet 1401. After the white glue 1502 is dispensed, the flip-chip LED structure is left to stand in an environment of 43°C for 1-2 hours. At this time, the viscosity of the white glue 1502 reaches the lowest, and the LED structure is turned off. By adopting the LED bracket electrode pad setting, the bottom height of the LED chip 1301 is increased by 30-50um. The solder thickness of the existing LED bracket is generally only 10-25um, so the bottom height of the LED chip 1301 is 10-25um. Compared with the flip-chip LED structure, the bottom height of the chip is increased from the original 10-25um to 40-75um. At this time, the white glue 1502 can easily flow into the bottom of the chip; when the white glue 1502 completely fills the bottom of the LED chip 1301, the flip-chip LED structure is placed in a 150℃ environment and baked for 3-4 hours to cure the white glue 1502. Figure 15 Of course, in other embodiments, when the flip-chip LED structure does not include the phosphor sheet 1401, during glue dispensing, a layer of white glue 1502 is sprayed around the LED chip 1301 and the LED bracket using glue dispensing equipment, and the flip-chip LED structure is left to stand in a 43°C environment for 1-2 hours, so that the white glue 1502 flows into the bottom of the LED chip 1301.

[0066] In this embodiment, in addition to controlling the temperature and time parameters of the white glue 1502 so that the white glue 1502 is completely filled into the bottom of the LED chip 1301, tools such as a centrifuge can also be used; for example, after using the dispensing equipment 1501 to spray a layer of white glue 1502 around the fluorescent sheet 1401 and the LED bracket, the flip-chip LED chip 1301 is placed in a centrifuge, and the white glue 1502 is centrifugally precipitated by the centrifuge. During the operation of the centrifuge, the white glue 1502 gradually sinks due to the centrifugal force, causing the white glue 1502 to flow into the bottom of the LED chip 1301. The centrifugal time can be flexibly adjusted according to the centrifugal force. For example, when the speed of the centrifuge is 1000-1200rpm, the centrifugal time of the centrifuge is 150-300s, thereby accelerating the flow of the white glue into the bottom of the chip electrode through the centrifugal process. In some embodiments, the material of the white glue can be changed to speed up the flow of the white glue to the bottom of the chip. For example, a diluent can be added to the white glue to reduce the viscosity of the white glue, or a white glue with a relatively low viscosity can be selected. When the white glue 1502 completely fills the bottom of the LED chip 1301, the flip-chip LED structure is placed in a 150°C environment and baked for 3-4 hours to cure the white glue 1502. Figure 15 shown.

[0067] This embodiment provides a method for manufacturing a flip-chip LED. By designing a new bracket, printing solder, placing the flip chip, attaching the phosphor sheet, and applying glue, the bottom and surrounding areas of the LED chip are completely covered with white glue, preventing vulcanization, silver migration, and flux overflow. It also minimizes reliability issues caused by thermal expansion of air beneath the LED chip. Furthermore, since only the phosphor glue above the LED chip emits light, the product offers excellent light directionality, making it suitable for applications with specialized requirements.

[0068] Example 3:

[0069] This embodiment provides a flip-chip LED chip structure manufactured by the manufacturing method provided in the second embodiment, such as Figure 16 As shown, the LED flip-chip LED chip structure includes an LED bracket 1601, an LED bracket 1602 flipped in the bowl of the LED bracket 1601, an insulating reflective adhesive 1603 formed in the bowl of the LED bracket 1601 to wrap around the LED bracket 1602, and a fluorescent sheet 1604 formed in the bowl of the LED bracket 1601 to cover the LED bracket 1602.

[0070] LED bracket 1601 includes a positive electrode 16011 and a negative electrode 16012. Within positive and negative electrodes 16011 and 16012, electrode region 1601a, where LED bracket 1602 is placed, is higher than other regions 1601b of positive and negative electrodes 16011 and 16012. Other regions 1601b include the areas of positive and negative electrodes 16011 and 16012 excluding electrode region 1601a, where LED bracket 1602 is placed. Electrode region 1601a is 30-50 μm higher than other regions 1601b. Electrode region 1601a and other regions 1601b of LED bracket 1601 are integrally formed. Therefore, during the manufacture of LED bracket 1602, insulating reflective adhesive 1603 can flow from the periphery of LED bracket 1602 to the bottom of LED bracket 1602.

[0071] The electrode region 1601a in this embodiment includes a positive electrode region 1601a and a negative electrode region 1601a, and the flip-chip LED bracket 1602 structure also includes a solder layer 1605 respectively arranged on the positive electrode region 1601a and the negative electrode region 1601a, and the thickness of the solder layer 1605 is 10-25um; the positive pin and the negative pin at the bottom of the LED bracket 1602 are respectively connected to the positive electrode region 1601a and the negative electrode region 1601a through the solder layer 1605, wherein the area formed by the positive electrode region 1601a and the negative electrode region 1601a is larger than the area of the LED bracket 1602.

[0072] It is worth noting that the insulating reflective glue 1603 in this embodiment includes white glue, which is arranged around the LED bracket 1602 and between the solder layers 1605 on the positive electrode area 1601a and the negative electrode area 1601a, and the height of the white glue on the solder layer 1605 bracket is level with the solder layer 1605 and the width is the same. Of course, white glue is also provided in the gap between the positive pole of the LED bracket 1601 and the negative pole 16012 of the bracket.

[0073] In this embodiment, the fluorescent sheet 1604 is located directly above the LED bracket 1602. The size of the fluorescent sheet 1604 is slightly larger than the size of the flip chip to avoid blue light leakage. The height of the fluorescent sheet 1604 is level with the height of the insulating reflective glue 1603. Specifically, the height of the insulating reflective glue 1603 in contact with the fluorescent sheet 1604 is the same as the height of the fluorescent sheet 1604, and the height of the insulating reflective glue 1603 in contact with the LED bracket 1601 is the same as the height of the bowl of the LED bracket 1601. In order to prevent the fluorescent sheet 1604 from being damaged during use or transportation of the product, the height of the fluorescent sheet 1604 in this embodiment is 30-60um lower than the horizontal plane of the bowl of the LED bracket 1601.

[0074] The flip-chip LED chip structure provided in this embodiment includes an integrally formed LED bracket, which includes a bracket positive electrode and a bracket negative electrode. The electrode area where the LED chip is placed is higher than other areas of the bracket positive electrode and the bracket negative electrode, and the electrode area is larger than other areas to prevent the LED chip from being unable to fully contact the bracket electrode when placed. At the same time, the electrode area is 30-50 μm higher than other areas, so that the insulating reflective adhesive can easily flow from the periphery of the LED chip to the bottom of the LED chip. The insulating reflective adhesive then covers the periphery of the LED chip and between the positive and negative pins at the bottom of the LED chip, isolating the positive and negative pins at the bottom of the LED chip from solder by the insulating reflective adhesive. This prevents the flux or silver in the solder from overflowing onto the silver-plated layer of the bracket after the LED has been operated for a period of time in a high-temperature or high-humidity environment. By completely filling the bottom surface of the LED chip with insulating reflective adhesive, it prevents sulfur in the environment from penetrating into the interior of the LED bracket after the LED has been used for a period of time and reacting chemically with the silver-plated layer inside the LED bracket, thereby causing LED vulcanization. It also avoids reliability problems caused by thermal expansion of the air at the bottom of the LED chip. In addition, the flip-chip LED chip structure provided in this embodiment also includes a fluorescent sheet covering the LED chip, so that only the fluorescent sheet above the LED chip emits light, and the light directionality is good, thereby improving product reliability.

[0075] It should be understood that the flip-chip LED chip structure provided in this embodiment can be applied to various lighting fields. For example, it can be made into a backlight module for use in the display backlight field (which can be a backlight module for terminals such as televisions, monitors, and mobile phones). In this case, it can be applied to the backlight module. It can also be applied to the key backlight field, the photography field, the home lighting field, the medical lighting field, the decoration field, the automotive field, the transportation field, and the like. When applied to the key backlight field, it can be used as a key backlight light source for mobile phones, calculators, keyboards, and other key devices; when applied to the photography field, it can be made into a camera flash; when applied to the home lighting field, it can be made into a floor lamp, table lamp, lighting lamp, ceiling lamp, downlight, projection lamp, etc.; when applied to the medical lighting field, it can be made into an operating lamp, a low-electromagnetic lighting lamp, etc.; when applied to the decoration field, it can be made into various decorative lamps, such as various colored lights, landscape lighting lamps, and advertising lamps; when applied to the automotive field, it can be made into car lights, car indicator lights, etc.; when applied to the transportation field, it can be made into various traffic lights or various street lights. The above applications are merely examples of applications in this embodiment. It should be understood that the applications of chip-scale packaged LEDs are not limited to the above examples.

[0076] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A flip-chip LED structure, characterized in that: include: An LED bracket, the LED bracket comprising a bracket positive electrode and a bracket negative electrode; an LED chip flipped inside the LED bracket bowl; An insulating reflective adhesive is formed in the LED bracket bowl to cover the LED chip, wherein the insulating reflective adhesive is a colloid with insulating and light reflecting functions; The electrode area of the positive electrode and the negative electrode of the bracket where the LED chip is placed is higher than other areas of the positive electrode and the negative electrode of the bracket, so that the insulating reflective adhesive covers the periphery and bottom of the LED chip but does not cover the upper surface of the LED chip, and the other areas include the areas of the positive electrode and the negative electrode of the bracket except the electrode area where the LED chip is placed; The bottom of the LED chip is provided with a positive electrode pin and a negative electrode pin, and the insulating reflective glue fills the insulating gap between the positive electrode pin and the negative electrode pin at the bottom of the LED chip.

2. The flip-chip LED structure according to claim 1, wherein: The positive electrode pin and the negative electrode pin are electrically connected to the positive electrode of the bracket and the negative electrode of the bracket respectively through solder provided on the electrode area, and the insulating reflective glue fills the insulating gaps between the solders.

3. The flip-chip LED structure according to claim 1, wherein: The area of the electrode region where the LED chip is placed is larger than the area of the LED chip.

4. The flip-chip LED structure according to claim 2, wherein: The area of the solder is smaller than the area of the electrode region.

5. A method for manufacturing a flip-chip LED structure, characterized in that: The production method comprises: Step S1: Designing and manufacturing an LED bracket, wherein the electrode area of the LED bracket where the LED chip is placed is higher than other areas of the LED bracket electrode; Step S2: printing solder on the raised electrode area; Step S3: flip-mounting the LED chip on the solder; Step S4: Glue dispensing. After the insulating reflective glue flows into the bottom of the LED chip, the insulating reflective glue is cured so that the insulating reflective glue covers the periphery and bottom of the LED chip but does not cover the upper surface of the LED chip. The insulating reflective glue is a colloid with insulating and light-reflecting functions. The bottom of the LED chip has a positive pin and a negative pin. The insulating reflective glue fills the insulating gap between the positive pin and the negative pin at the bottom of the LED chip.

6. The method for manufacturing a flip-chip LED structure according to claim 5, wherein: In step S2, the solder is printed on the electrode region through a 3D steel mesh, and the opening size of the 3D steel mesh is smaller than the area of the electrode region.

7. The method for manufacturing a flip-chip LED structure according to claim 5, wherein: In step S3, when the solder includes silver paste, the LED chip is placed on the solder and baked at a constant temperature of 170° C. for 1 hour; When the solder comprises solder paste or flux, the LED chip is placed on the solder and reflowed for 30 seconds in a nitrogen environment at a maximum furnace temperature of 290°C.

8. The method for manufacturing a flip-chip LED structure according to any one of claims 5 to 7, wherein: After step S3 and before step S4, the method further includes sticking a fluorescent sheet on the LED chip using a high-temperature resistant silicone resin and baking the fluorescent sheet at 150° C. for 3-4 hours.

9. The method for manufacturing a flip-chip LED structure according to claim 8, wherein: In step S4, the insulating reflective glue includes white glue, and a layer of white glue is sprayed around the fluorescent sheet and the LED bracket using a dispensing device, and the flip-chip LED structure is left to stand in an environment of 43°C for 1-2 hours so that the white glue flows into the bottom of the LED chip; or, the white glue is centrifuged and precipitated by a centrifuge so that the white glue flows into the bottom of the LED chip; when the white glue completely fills the bottom of the LED chip, the flip-chip LED structure is placed in an environment of 150°C and baked for 3-4 hours to cure the white glue.

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