CSP device and preparation method thereof, and light-emitting array structure

Abstract

The present invention provides a CSP device, a preparation method thereof, and a light-emitting array structure. Since the edge position of the light-emitting surface exceeds the edge position of the contact surface, the cross-section of the light conversion layer is an inverted trapezoid, and the light-emitting surface with a larger area is mounted on the surface of the LED chip with it facing upward. In combination with dry etching, the reflective layer of the light-emitting surface can be removed. Moreover, since the projected area of the light-emitting surface is larger than any other structure in the CSP device, a self-masking effect is formed during the dry etching process, and only the reflective layer on the light-emitting surface is precisely removed, effectively protecting other surfaces in the CSP device. This ensures that the dry etching process has no effect on the reflective layers on surfaces other than the light-emitting surface, especially the reflective layers on the side walls of the light conversion layer. Furthermore, no grinding is required during the entire preparation process, which effectively simplifies the packaging process and avoids product defects caused by grinding.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a CSP device and a preparation method thereof, and a light-emitting array structure. Background Art

[0002] As a next-generation packaging technology, CSP (Chip Scale Package) has attracted widespread attention due to its advantages, including small package size, high light output per unit area, and low manufacturing cost. Existing CSPs are typically compatible with flip-chip LED chips, and common packaging styles include five-sided and single-sided. Five-sided CSPs, due to a lack of shielding on all sides, suffer from poor light color uniformity and directivity, making them difficult to meet the stringent requirements of high-end applications. Single-sided CSPs employ a more ingenious design, using a light conversion layer as the white light conversion layer and a reflective layer to tightly wrap the package body, achieving an effect where only the front side emits light, while all other sides are effectively shielded.

[0003] Reflective layer materials vary, with the following three common types: 1) using metal as the reflective layer; 2) wrapping the LED chip with a high-reflectivity white glue made by doping silicone with reflective particles, such as TiO2; and 3) using a multi-layer DBR (distributed Bragg reflector) structure composed of two materials with different refractive indices alternating between them. While both metal and white glue offer excellent reflective properties, metal reflective layers are susceptible to contamination and damage during packaging. Excessive white glue thickness (up to 50µm, at least half the size of a single side of the LED chip) compresses the light-emitting area, hindering the creation of a compact, high-contrast light source. The DBR reflective layer's thickness is specifically designed to efficiently reflect specific wavelengths of light, making it a particularly advantageous option for single-sided CSPs, particularly in applications requiring high illumination and contrast, such as automotive lighting.

[0004] During the fabrication process, if the DBR structure is simultaneously deposited on the light-emitting surface of the package, it is usually necessary to grind and remove the light-emitting surface to ensure good directionality of the single-sided light emission of the package. Currently, the grinding process presents many challenges: on the one hand, the process is extremely difficult to control, and scratches can easily appear on the light-emitting surface; on the other hand, the thickness and uniformity of the grinding are difficult to control, which directly affects the uniformity of the chip's light output and the yield rate. In addition, high-precision grinding equipment is often expensive and consumes a large amount of grinding consumables such as grinding fluid and grinding wheels during use, which undoubtedly significantly increases production costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing CSP device needs to undergo a complex grinding process after DBR coating, resulting in poor light output of the product. To address this technical problem, the present invention provides a CSP device and a preparation method thereof, as well as a light-emitting array structure.

[0006] The technical solution provided by the present invention is:

[0007] In one aspect, the present invention provides a CSP device, comprising:

[0008] An LED chip having a light-emitting upper surface and a chip electrode, wherein the chip electrode includes an electrode surface opposite to the light-emitting upper surface;

[0009] The light conversion layer has a contact surface and a light emitting surface that match the shape of the light emitting surface of the LED chip, and a side wall connected between the contact surface and the light emitting surface is inclined;

[0010] The light conversion layer covers the light emitting surface of the LED chip through the contact surface, and along the vertical direction, the edge position of the light emitting surface exceeds the edge position of the contact surface;

[0011] The reflective layer covers all surfaces of the CSP device except the electrode surface and the light-emitting surface of the light conversion layer.

[0012] In another aspect, the present invention provides a method for preparing a CSP device, comprising:

[0013] Provide a whole light conversion layer and cut it according to the shape of the light-emitting surface of the LED chip to obtain a matching light conversion layer;

[0014] The light conversion layer obtained by cutting has a contact surface and a light emitting surface that match the shape of the light emitting surface of the LED chip, and the side wall connected between the contact surface and the light emitting surface is inclined;

[0015] Mounting a light conversion layer on the light emitting surface of the LED chip, wherein the light conversion layer covers the light emitting surface of the LED chip through the contact surface;

[0016] Depositing a reflective layer on the surface of the LED chip mounted with the light conversion layer, wherein the LED chip is arranged on the surface of the support film with the electrode facing downward, and the reflective layer is deposited on all surfaces except the electrode surface in contact with the support film;

[0017] Dry etching removes the reflective layer on the light-emitting surface of the light conversion layer in the vertical direction to form a reflective layer covering all surfaces except the electrode surface and the light-emitting surface of the light conversion layer;

[0018] The support film is removed to obtain a CSP device.

[0019] In another aspect, the present invention provides a light emitting array structure, comprising:

[0020] A supporting substrate having a conductive circuit configured on its surface;

[0021] A plurality of CSP devices as described above are fixed on the conductive circuit of the support substrate, and the arrangement thereof matches the conductive circuit.

[0022] The CSP device, preparation method thereof, and light-emitting array structure provided by the present invention have an inverted trapezoidal cross-section of the light conversion layer because the edge of the light-emitting surface extends beyond the edge of the contact surface. The larger light-emitting surface is mounted upward on the surface of the LED chip. Combined with dry etching, the reflective layer on the light-emitting surface can be removed. Furthermore, because the projected area of the light-emitting surface is larger than any other structure in the CSP device, a self-masking effect is formed during the dry etching process, thereby accurately removing the reflective layer on the light-emitting surface and effectively protecting other surfaces in the CSP device. This ensures that the dry etching process has no effect on the reflective layers on surfaces other than the light-emitting surface, especially on the reflective layers on the sidewalls of the light conversion layer. Furthermore, no grinding is required during the entire preparation process, effectively simplifying the packaging process and avoiding product defects caused by grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a CSP device according to an embodiment of the present invention;

[0024] Figure 2 is a schematic structural diagram of a light conversion layer in another embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of arranging LED chips on the surface of a support film in another embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of mounting a light conversion layer on the surface of an LED chip in another embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of depositing a reflective layer in another embodiment of the present invention;

[0028] Figure 6 FIG. 4 is a schematic diagram of dry etching a reflective layer according to another embodiment of the present invention.

[0029] Reference numerals:

[0030] 10-support film, 20-LED chip, 21-chip electrode, 22-light-emitting surface, 23-electrode surface, 30-adhesive layer, 40-light conversion layer, 41-contact surface, 42-light-emitting surface, 50-reflective layer. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0032] A first embodiment of the present invention provides a CSP device, comprising: an LED chip having a light-emitting top surface and a chip electrode, the chip electrode including an electrode surface opposite the light-emitting top surface; a light conversion layer having a contact surface and a light-emitting surface that match the shape of the light-emitting top surface of the LED chip, with an inclined sidewall connected between the contact surface and the light-emitting surface; the light conversion layer covering the light-emitting top surface of the LED chip via the contact surface, with the edge of the light-emitting surface extending vertically beyond the edge of the contact surface; and a reflective layer covering all surfaces of the CSP device except the electrode surface and the light-emitting surface of the light conversion layer.

[0033] In this embodiment, the LED chip is a flip-chip, with the surface where the chip electrode is located facing the light-emitting surface. The chip electrode is a protruding columnar shape formed by a combination of Sn or Cu, Ni, and Au, making it easy to solder the CSP device through the electrode after packaging. The light-emitting surface can be circular, square, polygonal, etc. Depending on the shape of the chip's light-emitting surface, the side surface connecting the light-emitting surface and the surface where the electrode is located can be a curved surface, or it can be composed of multiple planes connected. This embodiment does not impose any restrictions on this. As long as the chip electrode is connected to an appropriate current, the LED chip can emit light normally. Usually, the light-emitting surface of an LED chip is a quadrilateral, and the side surfaces are composed of four connected planes. The entire LED chip has six surfaces, including the surface where the chip electrode is located, the light-emitting surface opposite to the surface where the chip electrode is located, and four side surfaces between the electrode surface and the light-emitting surface. The light-emitting color of the LED chip itself is blue, red, etc. After the light enters the light conversion layer configured on the light-emitting surface, it is excited and converted into the light color and parameters required by the product. The light conversion layer contains a wavelength conversion material that converts the transmitted light into another wavelength. The wavelength conversion material is a phosphor that can be excited by the light emitted by the LED chip. Therefore, the color and other parameters of the light emitted from the light-emitting surface of the light conversion layer can change relative to the light color of the LED chip itself.

[0034] To achieve better light extraction, the shape of the light conversion layer is consistent with the light-emitting surface of the LED chip. When the light-emitting surface is square, the top view of the contact surface and the light-emitting surface of the light conversion layer are also square; when the light-emitting surface is circular, the top view of the contact surface and the light-emitting surface of the light conversion layer are also circular. Generally speaking, the shape of the light-emitting surface of the LED chip is a centrally symmetrical figure. Similarly, the light conversion layer (including the contact surface and the light-emitting surface) is also a centrally symmetrical figure. That is, the light conversion layer has a centrally symmetrical structure, and after mounting, the center of the light conversion layer coincides with the center of the light-emitting surface of the LED chip (within a certain error threshold range). In the vertical direction, the edge of the light-emitting surface extends beyond the edge of the contact surface, that is, the area of the light-emitting surface is larger than the area of the contact surface. There are no specific restrictions on the area of the light conversion layer or the inclination of the sidewalls between the light-emitting surface and the contact surface. In theory, as long as the sidewalls of the light conversion layer are inclined away from the LED chip and the angle between the inclined sidewalls and the light-emitting surface is an acute angle, it is sufficient. In this unique light conversion layer structure, the horizontal width gradually increases from the contact surface to the light-emitting surface, and the contact surface covers the light-emitting surface of the LED chip, allowing the projection of the light-emitting surface to cover the entire CSP device. This allows the reflective layer to be deposited simultaneously on the light-emitting surface of the light conversion layer during the fabrication process. This layer can then be precisely removed directly through dry etching, leveraging the self-masking effect. (Plasma bombardment only affects the light-emitting surface of the light conversion layer, etching the reflective layer there, without affecting other structures in the CSP device, particularly the reflective layer on the sidewalls of the light conversion layer.)

[0035] In order to further reduce the packaging volume of the CSP device, the area ratio between the light conversion layer and the light-emitting surface of the LED chip can be appropriately reduced without affecting the light output of the CSP device. For example, the area ratio between the contact surface and the light-emitting surface can be limited to 1.1:1, 1.05:1, etc., which are not specifically limited here. The light conversion layer is attached to the surface of the light-emitting surface of the LED chip through an adhesive layer. The adhesive layer is generally a material with high visible light transmittance that does not affect the light from the LED chip entering the light conversion layer, such as epoxy resin, thermosetting polyimide resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, thermosetting polyurethane resin and other thermosetting resins. The adhesive layer material is formed on the contact surface of the light conversion layer by dot coating in the preset position of the LED chip, so as to facilitate the light conversion layer and the LED chip to be firmly combined together. As long as the light conversion layer is located in the center of the light-emitting surface of the LED chip, it is sufficient.

[0036] The reflective layer covers all surfaces of the CSP device except the electrode surfaces and the light-emitting surface of the light conversion layer. Made of an insulating material, it exhibits a certain degree of reflectivity. It reflects light from the side of the CSP device, along with the sidewalls of the LED chip itself and the sidewalls of the light conversion layer. This ensures that light exits only from the light-emitting surface, isolating it from light from adjacent CSP devices and preventing optical crosstalk. The reflective layer is made of a periodic stack of low-refractive-index insulating oxide materials and high-refractive-index insulating oxide materials. The low-refractive-index material can be selected from relatively low-refractive-index insulating materials such as SiO2, MgF2, and Al2O3, while the high-refractive-index material can be selected from relatively high-refractive-index insulating materials such as TiO2 and Nb2O5. The layer closest to the LED chip is made of a low-refractive-index insulating oxide material, forming a distributed Bragg reflector (DBR) structure. The overall thickness of the DBR film ranges from 2µm to 4µm. The number of periodic structures can be determined based on actual conditions, as long as it satisfies the objective of preventing optical crosstalk. In one embodiment, SiO2 and TiO2 are alternately formed in 15 to 25 cycles to form a DBR film layer with a total thickness of about 3 μm to 4 μm as a reflective layer.

[0037] The reflective layer is formed using an ALD (atomic layer deposition) process. During the deposition process, the reflective material covers all external surfaces of the CSP device, including the sidewalls of the LED chip, the sidewalls of the chip electrodes, the sidewalls of the light conversion layer, the light-emitting surface, and the interface between the light conversion layer and the LED chip. Subsequently, the reflective layer on the light-emitting surface is removed by dry etching. Because the light conversion layer has an inverted trapezoidal cross-section, a self-masking effect is created during the dry etching process, allowing the reflective layer on the light-emitting surface to be precisely removed, resulting in the CSP device. Compared to traditional fabrication methods, this embodiment utilizes a light conversion layer with an inverted trapezoidal cross-section, combined with the precisely controlled dry etching process to create a self-masking effect. This eliminates the need for grinding during the entire fabrication process, effectively simplifying the packaging process and avoiding product defects caused by grinding.

[0038] In one embodiment, the structures in the CSP device are as follows Figure 1 As shown, two CSP devices with the same structure are shown in the figure. In each CSP device, the LED chip 20 has a light-emitting surface 22 and a chip electrode 21, and the chip electrode includes an electrode surface 23 opposite to the light-emitting surface. The light conversion layer 40 is attached to the light-emitting surface of the LED chip through an adhesive layer 30, and has a contact surface 41 and a light-emitting surface 42 that match the shape of the light-emitting surface of the LED chip, and the sidewall connected between the contact surface and the light-emitting surface is inclined. The light conversion layer covers the light-emitting surface of the LED chip through the contact surface, and the edge position of the light-emitting surface exceeds the edge position of the contact surface in the vertical direction. The reflective layer 50 covers all surfaces of the CSP device except the electrode surface 23 and the light-emitting surface 42 of the light conversion layer.

[0039] Another embodiment of the present invention provides a method for preparing a CSP device, such as Figure 2-Figure 6 Shown, including:

[0040] S10 provides a whole light conversion layer, which is cut according to the shape of the light-emitting surface of the LED chip to obtain a matching light conversion layer.

[0041] The light conversion layer is a pre-prepared and uncut piece of fluorescent film layer. It is cut according to the shape and area of the light-emitting surface of the LED chip to obtain a light conversion layer of matching size. Figure 2 As shown, the cut light conversion layer 40 has a contact surface 41 and a light emitting surface 42 that match the shape of the LED chip's light-emitting surface. The sidewall connecting the contact surface and the light-emitting surface is inclined. Generally speaking, the area of the light conversion layer is larger than the area of the LED chip's light-emitting surface. The area ratio can be determined based on actual conditions. To further reduce the package volume of the CSP device, the area ratio of the light conversion layer to the LED chip's light-emitting surface can be appropriately reduced without affecting the CSP device's light output. For example, the area ratio of the contact surface to the light-emitting surface can be limited to 1.1:1, 1.05:1, etc., but this is not specifically limited here.

[0042] In addition, it should be noted during the cutting process that the light conversion layer does not have a conventional vertical side wall, but an inclined side wall. A specific cutting method should be used, such as designing the cutting tool to a certain tilt angle before cutting the fluorescent film to make the side wall between the light emitting surface and the contact surface tilted to form a Figure 2 The structure in the CSP device is constructed (the horizontal width of the light conversion layer gradually increases from the contact surface to the light-emitting surface), and the projection of the light-emitting surface covers the entire CSP device. In this way, during the manufacturing process, after the reflective layer is synchronously deposited on the light-emitting surface of the light conversion layer, it can be precisely removed directly through dry etching using the self-masking effect (during plasma bombardment, the plasma only acts on the light-emitting surface of the light conversion layer and etches the reflective layer on its surface, without affecting other structures in the CSP device, especially the reflective layer on the sidewalls of the light conversion layer). There is no specific limit on the size of the tilt angle a. Theoretically, any angle can be acute, such as 89°, 85°, 80°, 75°, 70°, or even smaller. In practical applications, to ensure light emission from the CSP device, the tilt angle a can be designed to be greater than 45°.

[0043] S20: Mounting a light conversion layer on the light emitting surface of the LED chip, wherein the light conversion layer covers the light emitting surface of the LED chip through a contact surface.

[0044] The function of the support film is to support the LED chip and facilitate the subsequent packaging process. It can be a UV film or other film that is easy to remove after the packaging is completed. The LED chip is a flip-chip, and the surface where the chip electrode is located is opposite to the light-emitting surface. The chip electrode is a protruding columnar shape, formed by a combination of Sn or Cu, Ni and Au, which facilitates the soldering of the CSP device through the electrode after the packaging is completed. The light-emitting surface can be circular, square, polygonal, etc. Depending on the shape of the chip's light-emitting surface, the side surface connecting the light-emitting surface and the electrode surface can be a curved surface, or it can be composed of multiple planes connected. This embodiment does not impose any restrictions on this. As long as the chip electrode is connected to an appropriate current, the LED chip can emit light normally. Usually, the light-emitting surface of the LED chip is a quadrilateral, and the side surface is composed of four connected planes. The entire LED chip has six surfaces, including the surface where the chip electrode is located, the light-emitting surface opposite to the surface where the chip electrode is located, and four side surfaces between the electrode surface and the light-emitting surface. The light color of the LED chip itself is blue, red, etc. After the light enters the light conversion layer configured on the light-emitting surface, it is excited and converted into the light color and parameters required by the product. The light conversion layer contains a wavelength conversion material that converts the transmitted light into another wavelength. The wavelength conversion material is a phosphor that can be excited by the light emitted by the LED chip. Therefore, the color and other parameters of the light emitted from the light-emitting surface of the light conversion layer can change relative to the light color of the LED chip itself.

[0045] There are at least two ways to mount the light conversion layer on the light-emitting surface of the LED chip: one way is that after cutting the fluorescent film, the cross-section of the fluorescent film is arranged in a trapezoidal shape on the surface of the support film (the contact surface faces upward), and the LED chip (the light-emitting surface faces downward corresponding to the contact surface of the fluorescent film) is mounted on the surface of the fluorescent film. After the mounting is completed, since the electrode of the LED chip faces upward, in order to avoid the reflective layer from being deposited on the electrode surface and needing to be ground, the LED chip is subsequently flipped so that the electrode faces downward, and then the reflective layer is deposited.

[0046] Another method is to place the LED chips with their electrodes facing downward on the support film surface, and then attach the corresponding light conversion layers one by one to the light-emitting surface of the LED chips. Since the LED chips are facing downward, the reflective layer can be deposited directly without flipping them.

[0047] like Figure 3 and Figure 4As shown, LED chip 20 is arranged on the surface of support film 10 with its chip electrode facing downward and its luminous surface 22 facing upward. Light conversion layer 40 is attached to the luminous surface of the LED chip via adhesive layer 30. The adhesive layer is typically made of a material with high visible light transmittance that does not affect the passage of light from the LED chip into the light conversion layer. The adhesive layer may be a thermosetting resin such as epoxy resin, thermosetting polyimide resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, or thermosetting polyurethane resin. The adhesive layer is applied by dotting onto the contact surface of the light conversion layer, pre-determined to correspond to the position of the LED chip, so that the light conversion layer is positioned centrally on the luminous surface of the LED chip.

[0048] S30 deposits a reflective layer on the surface of the LED chip mounted with the light conversion layer, the LED chip is arranged on the surface of the support film with the electrode facing downward, and the reflective layer is deposited on all surfaces except the electrode surface in contact with the support film.

[0049] The reflective layer is made of a periodic stack of low-refractive-index insulating oxide materials and high-refractive-index insulating oxide materials. The low-refractive-index material can be selected from relatively low-refractive-index insulating materials such as SiO2, MgF2, and Al2O3, while the high-refractive-index material can be selected from relatively high-refractive-index insulating materials such as TiO2 and Nb2O5. The layer closest to the LED chip is made of the low-refractive-index insulating oxide material, forming a distributed Bragg reflector (DBR) structure. The overall thickness of the DBR film is 2µm to 4µm. The number of periodic structures can be determined based on actual conditions, as long as it can effectively prevent optical crosstalk. In one example, a DBR film with a total thickness of approximately 3µm to 4µm is formed by alternating SiO2 and TiO2 for 15 to 25 periods, serving as the reflective layer.

[0050] The reflective layer is formed by ALD (atomic layer deposition) process, such as Figure 5 As shown, before the reflective layer is deposited, the LED chip is arranged on the support film with its electrodes facing downward. Therefore, during the deposition process, the reflective layer 50 covers all external surfaces of the CSP device except the electrode surfaces. Since the LED chip is placed on the support film with its electrodes facing downward, only the electrode surfaces are directly in contact with the support film and are not covered by the reflective layer. Other external surfaces, including the sidewalls of the LED chip 20, the sidewalls of the chip electrode 21, the sidewalls and light-emitting surface of the light conversion layer 40, the connection surface between the light conversion layer and the LED chip, and the surface of the support film, are all covered by the reflective layer.

[0051] S40 Dry etching is performed along a vertical direction to remove the reflective layer on the light-emitting surface of the light conversion layer, so as to form a reflective layer covering all surfaces except the electrode surface and the light-emitting surface of the light conversion layer.

[0052] like Figure 6As shown, the inverted trapezoidal cross-section of the light conversion layer creates a self-masking effect during the dry etching process. During bombardment, plasma b acts only on the light-emitting surface of the light conversion layer 40 and etches the reflective layer thereon, without affecting other structures within the CSP device, particularly the reflective layer on the sidewalls of the light conversion layer. This allows the reflective layer on the light-emitting surface to be precisely removed to produce a CSP device. Compared to conventional fabrication methods, this embodiment utilizes the inverted trapezoidal cross-section of the light conversion layer, combined with the self-masking effect created by dry etching, eliminating the need for grinding during the entire fabrication process. This effectively simplifies the packaging process and avoids product defects caused by grinding.

[0053] The gas used in dry etching can be selected according to actual conditions, such as F-based chemical gas for dry etching. In order to increase the physical bombardment etching effect in the vertical direction, avoid etching the reflective layer on the side of the device (to prevent the reflective layer from reacting with the introduced gas), and improve the etching accuracy, CF4 / O2 / Ar mixed gas or SF6 / O2 / Ar mixed gas can be used for etching, and the mixed gas ratio is limited to (100±50) sccm: (0~20) sccm: (0~25) sccm, the source power is limited to 200w ~ 1000w, the bias power is limited to 0 ~ 500w, and the etching time is limited to 200s ~ 2000s.

[0054] S50: removing the support film to obtain a CSP device.

[0055] Finally, we get Figure 1 In the CSP device shown, the reflective layer 50 covers all surfaces of the CSP device except the electrode surface and the light-emitting surface of the light conversion layer.

[0056] In another embodiment of the present invention, a light-emitting array structure is provided. The light-emitting array structure comprises: a support substrate having a conductive circuit configured on its surface; and a plurality of CSP devices as described above, the CSP devices being fixed to the conductive circuits of the support substrate and arranged in a manner that matches the conductive circuits so that each CSP device can be independently controlled by the conductive circuits. The CSP devices used in this embodiment are soldered to the surface of the support substrate via chip electrodes and are switched on and off via the conductive circuits on the support substrate surface. Each CSP device reflects light from the side through a reflective layer provided on its sidewalls, achieving single-sided illumination. This prevents optical crosstalk between adjacent CSP devices and avoids crosstalk. This allows for a more uniform and compact arrangement, i.e., the spacing between CSP devices can be designed to be closer, improving overall light uniformity. Furthermore, each CSP device utilizes a light conversion layer with an inverted trapezoidal cross-section, and is mounted on the surface of the LED chip with the larger light-emitting surface facing upward. Dry etching can be used to remove the reflective layer on the light-emitting surface. This allows for precise removal of the reflective layer on the light-emitting surface, eliminating the need for grinding during the entire manufacturing process. This effectively simplifies the packaging process and avoids product defects caused by grinding.

[0057] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a CSP device, characterized in that: include: A whole light conversion layer is provided, and cut according to the shape of the light-emitting surface of the LED chip to obtain a light conversion layer that matches the shape of the light-emitting surface of the LED chip; the cut light conversion layer has a contact surface and a light-emitting surface that match the shape of the light-emitting surface of the LED chip, and a side wall connected between the contact surface and the light-emitting surface is inclined; A light conversion layer is mounted on the light emitting surface of the LED chip, wherein the light conversion layer covers the light emitting surface of the LED chip through the contact surface; in the vertical direction, the edge position of the light emitting surface exceeds the edge position of the contact surface; Depositing a reflective layer on the surface of the LED chip mounted with the light conversion layer, wherein the LED chip is arranged on the surface of the support film with the electrode facing downward, and the reflective layer is deposited on all surfaces except the electrode surface in contact with the support film; Dry etching removes the reflective layer on the light-emitting surface of the light conversion layer in the vertical direction to form a reflective layer covering all surfaces except the electrode surface and the light-emitting surface of the light conversion layer; The support film is removed to obtain a CSP device.

2. The method for preparing a CSP device according to claim 1, wherein: The reflective layer is made of periodically stacked low-refractive-index insulating oxide material and high-refractive-index insulating oxide material, and the layer closest to the LED chip is made of low-refractive-index insulating oxide material.

3. The method for preparing a CSP device according to claim 1 or 2, wherein: The thickness of the reflective layer is 2µm~4µm.

4. The method for preparing a CSP device according to claim 1 or 2, wherein: The light conversion layer has a central symmetrical structure.

5. A CSP device, characterized in that: Prepared by the method according to any one of claims 1 to 4, comprising: An LED chip having a light-emitting upper surface and a chip electrode, wherein the chip electrode includes an electrode surface opposite to the light-emitting upper surface; The light conversion layer has a contact surface and a light emitting surface that match the shape of the light emitting surface of the LED chip, and a side wall connected between the contact surface and the light emitting surface is inclined; the light conversion layer covers the light emitting surface of the LED chip through the contact surface, and in the vertical direction, the edge position of the light emitting surface exceeds the edge position of the contact surface; The reflective layer covers all surfaces of the CSP device except the electrode surface and the light-emitting surface of the light conversion layer.

6. The CSP device according to claim 5, wherein: The reflective layer is made of periodically stacked low-refractive-index insulating oxide material and high-refractive-index insulating oxide material, and the layer closest to the LED chip is made of low-refractive-index insulating oxide material.

7. The CSP device according to claim 5 or 6, characterized in that: The thickness of the reflective layer is 2µm~4µm.

8. The CSP device according to claim 5 or 6, wherein: The light conversion layer has a central symmetrical structure.

9. A light emitting array structure, characterized in that: The light emitting array structure comprises: A supporting substrate having a conductive circuit configured on its surface; A plurality of CSP devices according to any one of claims 5 to 8, wherein the CSP devices are fixed on the conductive circuit of the support substrate and arranged in a manner matching the conductive circuit.

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