CSP packaging structure of LED

Abstract

The utility model relates to the field of LED chip packaging, in particular to a CSP (Chip Scale Package) structure of an LED. The CSP packaging structure of the LED provided by the utility model can comprise an LED chip, two conducting strips and a fluorescent part. The two conducting strips are respectively arranged on two electrodes of the LED chip; and the LED chip and the two conducting strips are embedded in the bottom surface of the fluorescent part. According to the utility model, the welding area of the LED chip is increased through the conducting strip, so that the adhesive force after the single LED is welded to the bonding pad is increased, convenience is provided for the application of the single LED, and the single LED can be directly welded on a flexible substrate or other products and cannot fall off from the bonding pad due to the vibration deformation of the products. And the conducting strip and the electrode of the LED chip are connected and then are embedded into the bottom surface of the fluorescent part together, so that the conducting strip and the LED chip are packaged into a whole, the LED chip transmits current through the conducting strip, and missing solder during welding can be avoided.

Description

Technical Field

[0001] The utility model relates to the field of LED chip packaging, and particularly relates to a CSP packaging structure of an LED. Background Art

[0002] CSP (Chip Scale Package) packaged LEDs have attracted much attention and favor due to their high reliability and small size. However, due to the small size of the LEDs with CSP packaging structure, the effective welding area is small and the adhesion is small during actual welding, resulting in the LEDs being easily detached from the pads, reducing the reliability and yield of the products. Especially for extremely small-sized LED chips such as 0402 and 0201, the adhesion between them and the pads is even smaller, and they are extremely likely to fall off the pads due to vibrations and deformations of the products.

[0003] The Chinese utility model patent with the publication number CN215600370U discloses a CSP LED packaging structure. By arranging a metal layer with a spacing from the LED chip electrodes on the periphery of the LED chip and encapsulating the LED chip and the metal layer with a fluorescent glue, the metal layer acts as an extended pad for the LED chip electrodes, increasing the weldable area of the CSP. However, the technical solution of this patent may have the phenomenon of dry soldering during welding, that is, the metal layer contacts the pad through solder while the electrodes of the LED chip have poor contact with the pad. The technical solution of this patent has problems such as the thickness of the pressed fluorescent film, and the metal layer and the LED may not be on the same horizontal plane, resulting in dry soldering of the LED chip during welding. There may also be a situation where the area of the metal block around the LED chip is much larger than the area of the LED chip electrodes. After the solder melts, due to the surface tension of the solder, the solder will deflect from the chip part to the metal block, resulting in poor chip welding (dry soldering). Summary of the Invention

[0004] The invention object of the utility model is to: aiming at the problem of insufficient adhesion after a single CSP-packaged LED chip is welded to a pad in the prior art, provide a CSP packaging structure of an LED, so that the adsorbed force of the CSP-packaged LED chip after welding is sufficient and the conductivity is good.

[0005] In order to achieve the above object, the technical solution adopted by the utility model is:

[0006] A CSP packaging structure of an LED at least includes: an LED chip, two conductive sheets and a fluorescent part. Preferably, the two conductive sheets are respectively arranged on the two electrodes of the LED chip; and the LED chip and the two conductive sheets are embedded in the bottom surface of the fluorescent part.

[0007] According to a preferred embodiment, the two electrodes are arranged on the same plane of the LED chip.

[0008] According to a preferred embodiment, the conductive sheet covers the electrode connected thereto.

[0009] According to a preferred embodiment, the LED chip is rectangular, and the conductive sheet is also arranged to be rectangular.

[0010] According to a preferred embodiment, the length of the long side of the conductive sheet is at least 1.5 times the length of the short side of the LED chip.

[0011] According to a preferred embodiment, the length of the short side of the conductive sheet is at least 0.15 times the length of the long side of the LED chip.

[0012] According to a preferred embodiment, the distance between the two conductive sheets is at least 0.15 mm.

[0013] According to a preferred embodiment, the thickness of the conductive sheet does not exceed 0.3 mm.

[0014] According to a preferred embodiment, the fluorescent part is arranged in a box shape, a groove is formed in the bottom surface thereof, and the groove is engaged with the LED chip and the two conductive sheets connected together.

[0015] According to a preferred embodiment, the conductive sheet is at least composed of one of gold, silver, copper, iron, aluminum, and tin.

[0016] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present utility model are as follows:

[0017] 1. By providing a conductive sheet, the welding area of the LED is increased, thereby increasing the adhesion after a single LED is welded to the pad, facilitating the application of a single LED chip, enabling a single LED to be directly welded on a flexible substrate or other products, and preventing it from falling off the pad due to vibration or deformation of the product.

[0018] 2. After the conductive sheet is connected to the electrode of the LED chip, they are together embedded in the bottom surface of the fluorescent part, that is, the conductive sheet and the LED chip are encapsulated as a whole, and the LED chip transmits current through the conductive sheet, avoiding dry soldering during welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a CSP package structure of a preferred embodiment of the present utility model;

[0020] Figure 2 is a cross-sectional schematic diagram of a CSP package structure of a preferred embodiment of the present utility model;

[0021] Figure 3Inverted schematic diagram of the connection between the conductive sheet and the LED chip in a preferred embodiment of the present utility model;

[0022] Figure 4 Front view schematic diagram of the connection between the conductive sheet and the LED chip in a preferred embodiment of the present utility model.

[0023] Markings in the figure: 110 - LED chip, 111 - electrode, 120 - conductive sheet, 130 - fluorescent part. Specific embodiments

[0024] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. Any technology implemented based on the content of the present invention belongs to the scope of the present invention.

[0025] In the description of the specific embodiments of the present invention, without special instructions, the expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / device / device is commonly used. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0026] In addition, if terms such as "horizontal", "vertical", "hanging", "parallel" etc. appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but it can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in the directions of "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still play its role in the solution of the present invention.

[0027] In addition, the expressions such as "first", "second", "third", etc. in the terms are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0028] In addition, in the description of the embodiments of the present invention, "several", "multiple", and "a number of" represent at least two. It can be any case such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even more than 9.

[0029] In addition, in the description of the technical solutions of the present invention, unless otherwise clearly specified / defined / restricted, when the terms "set", "installed", "connected", "linked", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, and threaded connection. Such a connection can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components.

[0030] Embodiment 1

[0031] This embodiment provides a CSP packaging structure for an LED. Refer to Figure 1 and Figure 2 , the CSP packaging structure for an LED provided in this embodiment may include: an LED chip 110, two conductive sheets 120, and a fluorescent part 130. Preferably, the two conductive sheets 120 are respectively arranged on two electrodes 111 of the LED chip 110; and the LED chip 110 and the two conductive sheets 120 are embedded in the bottom surface of the fluorescent part 130.

[0032] Figure 1 The fluorescent part 130 shown by the dotted line in

[0033] is set in a box shape, and a groove is opened on its bottom surface. After the LED chip 110 and the two conductive sheets 120 are connected, they can be embedded in the groove opened on the bottom surface of the fluorescent part 130.

[0034] In this embodiment, the conductive sheet 120 increases the welding area of the LED chip 110, thereby increasing the adhesion force after a single LED is welded to the pad, providing convenience for the application of a single LED, enabling a single LED to be directly welded on a flexible substrate or other products, and preventing it from falling off the pad due to vibrations or deformations of the product.

[0035] Embodiment 2

[0036] This embodiment is a further improvement on Embodiment 1, and repeated content will not be elaborated. In this embodiment, preferably, the two electrodes 111 are arranged on the same plane of the LED chip 110.

[0037] Preferably, the conductive sheet 120 covers the electrode 111 connected thereto.

[0038] Preferably, the LED chip 110 is rectangular, and the conductive sheet 120 is also arranged to be rectangular.

[0039] Preferably, the length of the long side of the conductive sheet 120 is at least 1.5 times the length of the short side of the LED chip 110.

[0040] Preferably, the length of the short side of the conductive sheet 120 is at least 0.15 times the length of the long side of the LED chip 110.

[0041] Preferably, the distance between the two conductive sheets 120 is at least 0.1 mm.

[0042] Preferably, the thickness of the conductive sheet 120 does not exceed 0.3 mm.

[0043] Preferably, the fluorescent part 130 is arranged in a box shape, and a groove is formed on its bottom surface, and the groove is engaged with the LED chip 110 and the two conductive sheets 120 connected together.

[0044] Preferably, the conductive sheet 120 is at least composed of one of gold, silver, copper, iron, aluminum, and tin.

[0045] Embodiment 3

[0046] This embodiment is a further improvement on Embodiment 1 and Embodiment 2. In this embodiment, the conductive sheet 120 can be made of copper foil.

[0047] Preferably, the conductive sheet 120 can be bonded (booding, a chip packaging process) to the electrode 111 of the LED chip 110 through the existing die bonding and wire bonding process for chip packaging. When manufacturing the packaging structure provided in this embodiment, the conductive sheet 120 can be bonded to the electrode 111 of the LED chip 110 only by using the existing die bonding and wire bonding equipment. See Figure 3 and Figure 4, place the LED chip 110 with the electrode 111 facing upward, and then bond the conductive sheet 120 to the electrode 111; after the conductive sheet 120 and the electrode 111 are bonded, place the LED chip 110 with the electrode 111 facing downward, and then press-fit a fluorescent film on the LED chip 110 to form a fluorescent part 130 that fits with the LED chip 110 and the two conductive sheets 120. By using existing packaging equipment, only the packaging process flow of existing LEDs needs to be adaptively adjusted to manufacture the packaging structure provided in this embodiment, without the need to re-develop production equipment, thereby reducing the manufacturing cost of the packaging structure provided in this embodiment; and through the process of pressing the fluorescent film, it can be ensured that the two conductive sheets 120 are in the same plane of the packaging structure, so that void soldering can be avoided during soldering due to the height difference at the soldering position.

[0048] Preferably, the conductive sheet 120 can cover the electrode 111. Preferably, the short side length of the conductive sheet 120 can exceed the width of the electrode 111, but in order to reduce the risk of short circuit between the two conductive sheets 120 during actual soldering, the distance between the two conductive sheets 120 after being respectively bonded to the electrode 111 is not less than 0.1 mm. Preferably, the minimum distance between the two conductive sheets 120 after being respectively connected to the electrode 111 can be set to 0.15 mm.

[0049] See Figure 2 , preferably, in this embodiment, the short side length of the conductive sheet 120 can be the same as the width of the electrode 111.

[0050] See Figure 1 and Figure 2 , preferably, after the fluorescent part 130 fits with the LED chip 110 and the two conductive sheets 120, the two conductive sheets 120 are separated by the fluorescent part 130.

[0051] The CSP packaging structure provided by the present utility model is applicable to single LED, especially LEDs with small specifications such as 0402 and 0201. The LED adopting the CSP packaging structure provided by the present utility model is suitable for being installed on wearable devices, such as light therapy masks, eye protectors and other devices.

[0052] For devices such as light therapy masks and eye protectors, the substrates used for soldering LEDs are mostly flexible or substrates with a certain curvature. Therefore, it is necessary to use LEDs with small specifications such as 0402 and 0201. If larger-sized LEDs such as 0805 and 0603 packaging specifications are used, the bending deformation of the wearable device during use will be restricted. Existing LEDs with small specifications such as 0402 and 0201 have limited soldering areas, resulting in small adhesion after being soldered to the pads and being easily detached from the pads due to substrate deformation, vibration, etc.

[0053] The LED with the CSP packaging structure provided by the present utility model increases the welding area of the LED by arranging a conductive sheet 120 on the electrode 111 of the LED chip 110, and can improve the adhesion force after a single LED is welded to the pad. After welding the LED with the CSP packaging structure provided by the present utility model, it can withstand a force of more than 2 kgf.

[0054] In the CSP packaging structure provided by the present utility model, the electrode 111 of the LED chip 110 is electrically connected after overlapping with the conductive sheet 120. The LED chip 110 transmits current through the conductive sheet 120. The conductive sheet 120 can perform the function of the electrode 111, and can avoid the situation that the solder only contacts the conductive sheet 120 during welding and does not contact the electrode 111 of the LED chip 110, resulting in the LED being non-welded.

[0055] In the CSP packaging structure provided by the present utility model, after the conductive sheet 120 is connected to the electrode 111 of the LED chip 110, they are embedded together in the bottom surface of the fluorescent part 130, avoiding the influence on the size specifications of the CSP packaging structure.

[0056] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A CSP packaging structure of an LED, characterized in that: The invention at least comprises: an LED chip (110), two conductive sheets (120) and a fluorescent part (130), wherein the two conductive sheets (120) are respectively arranged on two electrodes (111) of the LED chip (110); and the LED chip (110) and the two conductive sheets (120) are embedded in the bottom surface of the fluorescent part (130); the conductive sheet (120) covers the electrode (111) connected thereto; the fluorescent part (130) is arranged in a box shape, and a groove is provided on the bottom surface thereof, and the groove is engaged with the LED chip (110) and the two conductive sheets (120) connected together; and the two conductive sheets (120) are separated by the fluorescent part (130).

2. The CSP packaging structure of LED according to claim 1, characterized in that: The two electrodes (111) are arranged on the same plane of the LED chip (110).

3. The CSP packaging structure of LED according to claim 1, characterized in that: The LED chip (110) is rectangular, and the conductive sheet (120) is also rectangular.

4. The CSP packaging structure of LED according to claim 3, characterized in that: The length of the long side of the conductive sheet (120) is at least 1.5 times the length of the short side of the LED chip (110).

5. The CSP packaging structure of LED according to claim 3, characterized in that: The length of the short side of the conductive sheet (120) is at least 0.15 times the length of the long side of the LED chip (110).

6. The CSP packaging structure of LED according to claim 3, characterized in that: The distance between the two conductive sheets (120) is at least 0.15 mm.

7. The CSP packaging structure of LED according to claim 1, characterized in that: The thickness of the conductive sheet (120) does not exceed 0.3 mm.

8. The CSP packaging structure of LED according to claim 1, characterized in that: The conductive sheet (120) is made of at least one of gold, silver, copper, iron, aluminum and tin.

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