LED packaging structure and LED packaging method

Abstract

The invention discloses an LED packaging structure and an LED packaging method, and belongs to the technical field of chip packaging. The power supply electrode of the driving chip and the RGB electrode of the LED chip are led to the two layers of substrates respectively, amplification of the power supply electrode and the RGB electrode of the driving chip is achieved at the same time, on one hand, the size of the driving chip is enlarged in an electric connection mode, limitation on the size of the LED chip can be reduced, and the size of the LED chip can be reduced; compared with a traditional LED packaging structure, the LED packaging structure can adopt an LED chip with a larger size, so that the process mass production feasibility and the mass production efficiency can be improved; and on the other hand, a plurality of LED chips can be placed on the upper substrate, and the plurality of LED chips can be simultaneously driven through one driving chip, so that the integration level of the LED packaging structure can be improved, and the size of the LED packaging structure can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to an LED packaging structure and an LED packaging method. Background Art

[0002] Traditional light emitting diode (LED) packaging structures usually have multiple LED chips and multiple driver chips, and each driver chip is mounted with an LED chip, resulting in a larger size of this packaging structure. Moreover, the size of the driver chip directly determines the size of the LED chip. Since the size of the LED chip cannot exceed the size of the driver chip, the size of the LED chip is greatly limited. When preparing this packaging structure, it involves a large amount of transfer of extremely small LED chips, which will also reduce process efficiency and limit the yield. Summary of the invention

[0003] The object of the present invention is to provide an LED packaging structure and an LED packaging method, so as to improve process efficiency and reduce the size of the LED packaging structure.

[0004] To achieve the above object, the present invention provides an LED packaging structure, comprising: a first substrate, a second substrate, a driving chip and a plurality of LED chips;

[0005] The driving chip is disposed on the first surface of the second substrate; two first electrodes are disposed on the surface of the driving chip; and both of the two first electrodes are electrically connected to the first surface of the second substrate;

[0006] The first substrate is arranged on a side of the driver chip away from the second substrate; the first surfaces of the second substrates on both sides of the driver chip are electrically connected to the second surface of the first substrate; the second surface of the first substrate is electrically connected to the first surface of the first substrate; the first surface of the first substrate is the surface away from the driver chip; the second surface of the first substrate is the surface close to the driver chip;

[0007] The LED chip is disposed on the first surface of the first substrate and is electrically connected to the first surface of the first substrate.

[0008] Optionally, a first seed layer is disposed on the surfaces of the two first electrodes; a first conductive bump is disposed on the surface of the first seed layer; and the first conductive bump is electrically connected to the first surface of the second substrate.

[0009] Optionally, the second surface of the first substrate is provided with two second electrodes; the first surfaces of the second substrate on both sides of the driving chip are electrically connected to the two second electrodes one by one;

[0010] Two first slot structures are arranged in the first substrate; the two first slot structures are arranged on both sides of the driving chip respectively; and first conductive redistribution wiring is arranged on the inner surface of the first slot structure;

[0011] The first conductive redistribution wiring is led out from the top opening of the first slot structure and is electrically connected to the LED chip; the first conductive redistribution wiring is electrically connected to the second electrodes one by one through the bottom opening of the first slot structure.

[0012] Optionally, a first insulating layer is provided between the first conductive redistribution wiring and the inner surface of the first slot structure;

[0013] And / or, a first solder resist package is provided on a surface of the first conductive redistribution pattern away from the first slot structure; and a plurality of first through holes are provided in the first solder resist package;

[0014] The first conductive redistribution wiring is led out from the top opening of the first slot structure and is electrically connected to the LED chip through the first through hole.

[0015] Optionally, two third electrodes are provided on the second surface of the second substrate;

[0016] Two second slot structures are arranged in the second substrate; the two second slot structures are arranged on both sides of the driving chip respectively; and the inner surface of the second slot structure is provided with a second conductive redistribution wiring;

[0017] The second conductive redistribution wiring is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode one by one, and the other end is electrically connected to the second surface of the first substrate through a second conductive bump; a second seed layer is arranged between the second conductive bump and the second conductive redistribution wiring; the second conductive redistribution wiring is electrically connected to the third electrode one by one through the bottom opening of the second slot structure.

[0018] Optionally, a second insulating layer is provided between the second conductive redistribution wiring and the inner surface of the second slot structure;

[0019] And / or, a second solder resist package is provided on a surface of the second conductive redistribution pattern away from the second slot structure; and four second through holes are provided in the second solder resist package;

[0020] The second conductive redistribution wiring is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode one by one through the second through hole, and the other end is electrically connected to the second surface of the first substrate through the second conductive bump; the second conductive bump is located in the second through hole.

[0021] Optionally, the LED packaging structure further includes: plastic encapsulation glue; the plastic encapsulation glue is located on a side of the second conductive bump away from the driver chip and is arranged along the circumferential direction; the height of the plastic encapsulation glue is equal to the distance between the first substrate and the second substrate.

[0022] To achieve the above object, the present invention further provides an LED packaging method, comprising:

[0023] A driving chip, a first substrate and a second substrate are prepared; two first electrodes are arranged on the surface of the driving chip;

[0024] The driving chip is disposed on the first surface of the second substrate so that both of the first electrodes are electrically connected to the first surface of the second substrate;

[0025] The first substrate is arranged on a side of the driver chip away from the second substrate, so that the first surfaces of the second substrates on both sides of the driver chip are electrically connected to the second surface of the first substrate, and the second surface of the first substrate is electrically connected to the first surface of the first substrate; the first surface of the first substrate is the surface away from the driver chip; the second surface of the first substrate is the surface close to the driver chip;

[0026] An LED chip is disposed on the first surface of the first substrate, and the LED chip is electrically connected to the first surface of the first substrate to obtain an LED packaging structure.

[0027] Optionally, the step of preparing the driver chip, the first substrate and the second substrate includes:

[0028] Arranging a first seed layer on the surfaces of the two first electrodes, and arranging a first conductive bump on the surface of the first seed layer, to obtain the final driving chip;

[0029] Correspondingly, the first conductive bump is electrically connected to the first surface of the second substrate.

[0030] Optionally, the step of preparing the driver chip, the first substrate, and the second substrate includes:

[0031] Two second electrodes are arranged on the second surface of the first substrate, two first slot structures are arranged in the first substrate, and first conductive redistribution wiring is arranged on the inner surface of the first slot structure; the two first slot structures are arranged on both sides of the driving chip respectively; the first conductive redistribution wiring is led out from the top opening of the first slot structure, and the final second substrate is obtained;

[0032] Correspondingly, the first surface of the second substrate on both sides of the driving chip is electrically connected to the two second electrodes one by one; the first conductive redistribution is electrically connected to the second electrodes one by one through the bottom opening of the first slot structure; and the LED chip is electrically connected to the first conductive redistribution.

[0033] Obviously, the LED packaging structure provided by the present invention achieves the following beneficial effects by respectively leading the power electrode of the driver chip and the RGB electrodes of the LED chip to two layers of substrates, thereby simultaneously achieving the amplification of the power electrode and the RGB electrodes of the driver chip:

[0034] (1) Since the size of the driver chip is enlarged by electrical connection, the restriction on the size of the LED chip can be reduced. Therefore, compared with the traditional LED packaging structure, a larger LED chip can be used, thereby improving the feasibility of mass production and the efficiency of mass production;

[0035] (2) Multiple LED chips can be placed on the upper substrate, and multiple LED chips can be driven simultaneously by one driver chip, thereby improving the integration of the LED packaging structure and reducing the size of the LED packaging structure;

[0036] (3) The structure of three-dimensional integrated packaging of the driver chip through two layers of substrate is relatively simple, and has advantages in terms of feasibility and cost.

[0037] The present invention also provides an LED packaging method, which can prepare the above-mentioned LED packaging structure, and thus also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0039] Figure 1 A schematic diagram of an LED packaging structure provided by an embodiment of the present invention;

[0040] Figure 2 A flow chart of an LED packaging method provided by an embodiment of the present invention;

[0041] Figures 3 to 22 A schematic flow chart of an LED packaging method provided by an embodiment of the present invention.

[0042] The following are the descriptions of the reference numerals:

[0043] 101 - driving wafer; 102 - first electrode; 103 - first seed layer; 104 - photolithography film; 105 - first conductive bump;

[0044] 106 - first substrate; 107 - second electrode; 108 - first temporary bonding material; 109 - first glass; 110 - first insulating layer; 111 - first conductive redistribution; 112 - first solder resist encapsulation;

[0045] 113 - second substrate; 114 - third electrode; 115 - second temporary bonding material; 116 - second glass; 117 - second insulating layer; 118 - second conductive redistribution; 119 - second solder resist encapsulation; 120 - second seed layer; 121 - second conductive bump;

[0046] 122- plastic sealing adhesive; 123- LED chip. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Please refer to Figures 1 to 22 , an LED packaging structure provided by an embodiment of the present invention may include: a first substrate 106, a second substrate 113, a driving chip and a plurality of LED chips 123;

[0049] The driving chip is disposed on the first surface of the second substrate 113; two first electrodes 102 are disposed on the surface of the driving chip; the two first electrodes 102 are both electrically connected to the first surface of the second substrate 113;

[0050] The first substrate 106 is arranged on a side of the driver chip away from the second substrate 113; the first surfaces of the second substrates 113 on both sides of the driver chip are electrically connected to the second surface of the first substrate 106; the second surface of the first substrate 106 is electrically connected to the first surface of the first substrate 106; the first surface of the first substrate 106 is the surface away from the driver chip; the second surface of the first substrate 106 is the surface close to the driver chip;

[0051] The LED chip 123 is disposed on the first surface of the first substrate 106 and is electrically connected to the first surface of the first substrate 106 .

[0052] It should be noted that the first electrode 102 on the surface of the driver chip is a power supply electrode. The surface of the LED chip 123 is also provided with electrodes, which are RGB electrodes. The RGB electrodes are electrode structures for controlling and driving red (Red), green (Green) and blue (Blue) LED chips.

[0053] The present embodiment does not limit the specific structure of the driver chip, and may include but is not limited to the following structures: a first seed layer 103 is provided on the surface of both first electrodes 102; a first conductive bump 105 is provided on the surface of the first seed layer 103; the first conductive bump 105 is electrically connected to the first surface of the second substrate 113. The present embodiment does not limit the specific type of the first seed layer 103, and the first seed layer 103 may include but is not limited to a Ti layer and a Cu layer sequentially provided along the thickness direction. It should be noted that the Ti / Cu seed layer can enhance the bonding force of the subsequent preparation of the first conductive bump 105 and improve the quality of the first conductive bump 105. The present embodiment does not limit the specific type of the first conductive bump 105, and the first conductive bump 105 may include but is not limited to metal bumps such as copper bumps, nickel bumps, or tin-silver bumps.

[0054] This embodiment does not limit the specific structure of the first substrate 106, and may include but is not limited to the following structures:

[0055] Two second electrodes 107 are disposed on the second surface of the first substrate 106; the first surfaces of the second substrates 113 on both sides of the driving chip are electrically connected to the two second electrodes 107 one by one;

[0056] Two first slot structures are arranged in the first substrate 106; the two first slot structures are arranged on both sides of the driver chip respectively; the inner surface of the first slot structure is provided with a first conductive redistribution wiring 111;

[0057] The first conductive redistribution lines 111 are led out from the top opening of the first slot structure and are electrically connected to the LED chip 123 ; the first conductive redistribution lines 111 are electrically connected to the second electrodes 107 one by one through the bottom opening of the first slot structure.

[0058] This embodiment does not limit the specific type of the first substrate 106. The first substrate 106 may include, but is not limited to, a silicon substrate or a silicon dioxide substrate. The silicon dioxide substrate includes a silicon layer and a silicon dioxide layer sequentially arranged along the thickness direction.

[0059] This embodiment does not limit the specific type of the second electrode 107. The second electrode 107 may include but is not limited to a metal electrode. The material of the metal electrode may include but is not limited to one or more of gold, nickel, copper, tin, palladium, aluminum or titanium, and a multi-layer structure and material.

[0060] The present embodiment does not limit the specific type of the first conductive redistribution lines 111 , and the first conductive redistribution lines 111 may include, but are not limited to, metal redistribution lines.

[0061] This embodiment does not limit the specific shape of the first slot structure, and the first slot structure may be, but is not limited to, a stepped slot structure, and the size of the top opening of the stepped slot structure is larger than the size of the bottom opening. It should be noted that the first slot structure of this structure can be formed by TSV (Through-Silicon Via) packaging technology, which has a simple preparation process and is convenient for forming the first conductive redistribution wiring 111.

[0062] Further, in this embodiment, a first insulating layer 110 may be provided between the first conductive redistribution wiring 111 and the inner surface of the first slot structure. It should be noted that the first insulating layer 110 in this embodiment plays an insulating effect between the subsequent first conductive redistribution wiring 111 and the first substrate 106. This embodiment does not limit the specific type of the first insulating layer 110, and the first insulating layer 110 may be any insulating material. Further, the first insulating layer 110 may be a photoresist material.

[0063] Furthermore, in this embodiment, the surface of the first conductive redistribution 111 away from the first slot structure may be provided with a first solder resist encapsulation 112; a plurality of first through holes are provided in the first solder resist encapsulation 112; the first conductive redistribution 111 is led out from the top opening of the first slot structure, and is electrically connected to the LED chip 123 through the first through holes. It should be noted that the first solder resist encapsulation 112 in this embodiment can prevent oxidation, scratches / contamination and other abnormalities on the surface of the first conductive redistribution 111, thereby enhancing product reliability.

[0064] This embodiment does not limit the specific structure of the second substrate 113, and may include but is not limited to the following structures:

[0065] Two third electrodes 114 are disposed on the second surface of the second substrate 113;

[0066] Two second slot structures are disposed in the second substrate 113; the two second slot structures are disposed on both sides of the driver chip respectively; and the inner surface of the second slot structure is provided with a second conductive redistribution wiring 118;

[0067] The second conductive redistribution wiring 118 is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode 102 one by one, and the other end is electrically connected to the second surface of the first substrate 106 through the second conductive bump 121; a second seed layer 120 is arranged between the second conductive bump 121 and the second conductive redistribution wiring 118; the second conductive redistribution wiring 118 is electrically connected to the third electrode 114 one by one through the bottom opening of the second slot structure.

[0068] Furthermore, in this embodiment, a second insulating layer 117 may be disposed between the second conductive redistribution wiring 118 and the inner surface of the second slot structure.

[0069] Furthermore, in the present embodiment, a second solder resist package 119 may be provided on the surface of the second conductive redistribution wiring 118 facing away from the second slot structure; four second through holes are provided in the second solder resist package 119; the second conductive redistribution wiring 118 is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode 102 one by one through the second through hole, and the other end is electrically connected to the second surface of the first substrate 106 through the second conductive bump 121; the second conductive bump 121 is located in the second through hole.

[0070] It should be noted that, in this embodiment, two ends of each second conductive redistribution wiring 118 are provided with a second through hole.

[0071] It should be noted that, in this embodiment, the specific type of the second substrate 113, the specific type of the third electrode 114, the specific type of the second conductive redistribution 118 and the specific type of the second insulating layer 117 can all refer to the specific type of the first substrate 106, the specific type of the second electrode 107, the specific type of the first conductive redistribution 111 and the specific type of the first insulating layer 110, and will not be repeated here.

[0072] Furthermore, the LED packaging structure in this embodiment may further include: a plastic sealant 122; the plastic sealant 122 is located on the side of the second conductive bump 121 away from the driver chip and is arranged along the circumferential direction; the height of the plastic sealant 122 is equal to the distance between the first substrate 106 and the second substrate 113. It should be noted that the plastic sealant 122 in this embodiment can place the driver chip in a vacuum-tight environment, greatly improving the reliability of the product.

[0073] The present embodiment does not limit the specific type of the LED chip 123, and the LED chip 123 may be, but is not limited to, a micro-LED chip. The present embodiment does not limit the specific type of the LED chip 123, and the LED chip 123 may be, but is not limited to, an LED chip 123 in an LED lamp bead.

[0074] Based on the above embodiments, the present invention leads the power electrode of the driver chip and the RGB electrodes of the LED chip to two substrates respectively, thereby realizing the amplification of the power electrode and the RGB electrodes of the driver chip, and has the following beneficial effects:

[0075] (1) Since the size of the driver chip is enlarged by electrical connection, the restriction on the size of the LED chip can be reduced. Therefore, compared with the traditional LED packaging structure, a larger LED chip can be used, thereby improving the feasibility of mass production and the efficiency of mass production;

[0076] (2) Multiple LED chips can be placed on the upper substrate, and multiple LED chips can be driven simultaneously by one driver chip, thereby improving the integration of the LED packaging structure and reducing the size of the LED packaging structure;

[0077] (3) The structure of three-dimensional integrated packaging of the driver chip through two layers of substrate is relatively simple, and has advantages in terms of feasibility and cost.

[0078] Please refer to Figures 1 to 22 , an LED packaging method provided by an embodiment of the present invention may include:

[0079] S101: preparing a driving chip, a first substrate and a second substrate; two first electrodes are arranged on the surface of the driving chip.

[0080] This embodiment does not limit the specific order of preparing the driving chip, the first substrate 106 and the second substrate 113 .

[0081] This embodiment does not limit the specific method of preparing the driver chip, and can be but is not limited to the following method: a first seed layer 103 is set on the surface of the two first electrodes 102, and a first conductive bump 105 is set on the surface of the first seed layer 103 to obtain the final driver chip; accordingly, the first conductive bump 105 is electrically connected to the first surface of the second substrate 113.

[0082] This embodiment does not limit the specific method of preparing the first seed layer 103 and the first conductive bump 105, and can be but not limited to the following methods:

[0083] Step 1: forming a first seed layer 103 on the surface of a driving wafer 101; the driving wafer 101 includes a plurality of driving chips; and two first electrodes 102 are disposed on the surface of each driving chip.

[0084] The present embodiment does not limit the specific type of the first seed layer 103, and the first seed layer 103 may include, but is not limited to, a Ti layer and a Cu layer sequentially arranged along the thickness direction. It should be noted that the Ti / Cu seed layer can enhance the bonding force of the subsequent preparation of the first conductive bump 105 and improve the quality of the first conductive bump 105.

[0085] This embodiment does not limit the specific method of forming the first seed layer 103. The specific method of forming the first seed layer 103 can be determined according to the specific type of the first seed layer 103. For example, when the first seed layer 103 is a Ti / Cu seed layer, the first seed layer 103 can be formed on the surface of the driving wafer 101 through sputtering, evaporation and other process operations.

[0086] Step 2: Patterning is achieved by photolithography coating 104 on the surface of the first seed layer 103 facing away from the driving wafer 101 .

[0087] It should be noted that, in this embodiment, patterning is formed on the surface of the first seed layer 103 by photolithography coating 104 , so as to prepare for the subsequent preparation of the first conductive bumps 105 .

[0088] Step 3: After patterning is achieved, a first conductive bump 105 is formed on the surface of the first seed layer 103 away from the driving wafer 101 , and the first conductive bump 105 covers the first electrode 102 .

[0089] The present embodiment does not limit the specific type of the first conductive bump 105 , and the first conductive bump 105 may include, but is not limited to, metal bumps such as copper bumps, nickel bumps, or tin-silver bumps.

[0090] The present embodiment does not limit the specific method of forming the first conductive bump 105. The specific method of forming the first conductive bump 105 may be determined according to the specific type of the first conductive bump 105. For example, the first conductive bump 105 may be formed on the surface of the first seed layer 103 away from the driver wafer 101 by electroplating copper, nickel, tin-silver or other metals.

[0091] It should be noted that the electroplating process can improve the conductivity of metals, making them more suitable for application scenarios that require good conductivity.

[0092] Step 4: After forming the first conductive bump 105 , remove the photolithography film 104 and remove the exposed first seed layer 103 .

[0093] This embodiment does not limit the specific method of removing the first seed layer 103. The specific method of removing the first seed layer 103 can be determined according to the specific type of the first seed layer 103. For example, when the first seed layer 103 is a Ti / Cu seed layer, the exposed first seed layer 103 can be removed by wet etching.

[0094] It should be noted that, in the present embodiment, this step is to prepare for the subsequent separation of a single driver chip.

[0095] Step 5: After removing the exposed first seed layer 103 , separate a single driver chip from the driver wafer 101 .

[0096] It should be noted that the purpose of this step in the present embodiment is to separate a single driver chip on the driver wafer 101 to facilitate subsequent module processing and application.

[0097] This embodiment does not limit the specific method of separating a single driver chip, and a single driver chip can be separated from the driver wafer 101 by, but is not limited to, laser cutting, hidden cutting, or wheel cutting.

[0098] Furthermore, before step 5, the method may further include: changing the first conductive bump 105 into a spherical shape by reflow soldering.

[0099] It should be noted that, in the present embodiment, this step is to prepare for flip-chip bonding of the driving chip and the second substrate 113 .

[0100] Furthermore, before step 5, the method may also include: thinning the driver wafer 101 by grinding.

[0101] It should be noted that the purpose of this step in the present embodiment is to thin the driver wafer 101 to a suitable thickness to meet the process requirements of different driver chip thicknesses. Thinning can reduce the driver chip stress and improve the heat dissipation of the driver chip.

[0102] This embodiment does not limit the specific method of preparing the first substrate 106, and the following methods may be used but are not limited to:

[0103] Two second electrodes 107 are disposed on the second surface of the first substrate 106, and two first slot structures are disposed in the first substrate 106, and first conductive redistribution wiring 111 is disposed on the inner surface of the first slot structure; the two first slot structures are disposed on both sides of the driver chip respectively; the first conductive redistribution wiring 111 is led out from the top opening of the first slot structure, and the final second substrate 113 is obtained;

[0104] Correspondingly, the first surfaces of the second substrate 113 on both sides of the driving chip are electrically connected to the two second electrodes 107 one by one; the first conductive redistribution wiring 111 is electrically connected to the second electrodes 107 one by one through the bottom opening of the first slot structure; and the LED chip 123 is electrically connected to the first conductive redistribution wiring 111.

[0105] This embodiment does not limit the specific method of preparing the second electrode 107, the first slot structure and the first conductive redistribution wiring 111, and can be but not limited to the following methods:

[0106] Step 1: two second electrodes 107 are disposed on the second surface of the first substrate 106 .

[0107] The present embodiment does not limit the specific type of the second electrode 107. The second electrode 107 may include, but is not limited to, a metal electrode; the material of the metal electrode may include, but is not limited to, one or more of gold, nickel, copper, tin, palladium, aluminum, or titanium, a multi-layer structure, and a material. The present embodiment does not limit the specific manner of setting the second electrode 107. The specific manner of forming the second electrode 107 may be determined according to the specific type of the second electrode 107. For example, when the second electrode 107 is a metal electrode, a metal wiring layer may be implemented on the second surface of the first substrate 106 using wafer-level packaging technology; the metal wiring layer includes a plurality of pairs of second electrodes 107.

[0108] Step 2: After forming the two second electrodes 107 , two first slot structures are disposed in the first substrate 106 .

[0109] This embodiment does not limit the specific method of setting the first slot structure, and can be but not limited to the following method: using a photolithography process and a dry etching process to etch away excess first substrate 106, to carve grooves and through holes, to form the first slot structure.

[0110] The specific process is as follows: a photoresist material (such as photoresist) having photoresist properties is used to cover the first surface of the first substrate 106; a mask having a special pattern is then used to perform a photosensitive treatment under light of a specific wavelength, and then a chemical agent is used for development to produce a photoresist pattern; then the excess first substrate 106 is etched using a dry etching process; the portion not covered by the photoresist will be removed by an active fluorine ion etching reaction, thereby achieving the purpose of removing the excess first substrate 106; a wet etching process may also be used to replace the dry etching process; after the etching of the first substrate 106 is completed, the protective layer photoresist on the first surface of the first substrate 106 must also be removed; and finally, the first surface of the first substrate 106 is cleaned.

[0111] Furthermore, before step 2, the method may further include: coating a removable first temporary bonding material 108 on the surface of the first glass 109 to bond the first glass 109 to the second surface of the first substrate 106 .

[0112] It should be noted that, in the present embodiment, this step is for the first substrate 106 to serve as a carrier during the subsequent packaging and transmission process, thereby preventing the first substrate 106 from being broken into pieces due to being too thin.

[0113] The present embodiment does not limit the specific type of the first temporary bonding material 108, and the first temporary bonding material 108 may be a glue layer or a double-layer film. The present embodiment does not limit the specific bonding method, and the specific bonding method may be determined according to the specific type of the first temporary bonding material 108. For example, when the first temporary bonding material 108 is a glue layer (i.e., a temporary bonding glue), the first glass 109 may be bonded to the second surface of the first substrate 106 by using the viscosity of the temporary bonding glue, and by using parameters such as pressure, temperature, and UV (Ultraviolet Rays) characteristics.

[0114] It should be noted that, before step 4, the process also includes: performing debonding to separate the first glass 109 from the first substrate 106 .

[0115] This embodiment does not limit the specific method of debonding. According to the characteristics of the temporary bonding adhesive, debonding can be performed by heating, laser or UV photolysis.

[0116] Furthermore, before step 2, the method may further include: thinning the first substrate 106 .

[0117] It should be noted that in order to achieve ultra-thin first substrate 106 after packaging, the first substrate 106 needs to be thinned.

[0118] This embodiment does not limit the specific method of thinning, and can be but not limited to mechanical grinding process using a diamond grinding wheel, or mechanical chemical grinding and polishing, or plasma dry etching, or wet etching using a fluorine-containing solution to thin the first substrate 106. Preferably, the method of plasma dry etching is used after mechanical grinding with a diamond grinding wheel. It should be noted that the advantage of this method is that the mechanical grinding process is fast, but stress and a micro-damage layer will be generated on the surface of the first substrate 106. Then, the micro-damage layer is removed by a plasma dry etching method, the surface stress is released, and the warping problem of the first substrate 106 is eliminated.

[0119] This embodiment does not limit the specific thickness of the first substrate 106 after thinning, and the thickness can be adjusted arbitrarily according to specific application requirements. For example, the thickness of the first substrate 106 after thinning can be 20 μm to 200 μm, including both ends.

[0120] Step 3: After forming the first slot structure, a first conductive redistribution line 111 is disposed on the inner surface of the first slot structure.

[0121] This embodiment does not limit the specific type of the first conductive redistribution 111, and the first conductive redistribution 111 may include, but is not limited to, metal redistribution. This embodiment does not limit the specific manner of setting the first conductive redistribution 111, and the specific manner of setting the first conductive redistribution 111 may be determined according to the specific type of the first conductive redistribution 111. For example, when the first conductive redistribution 111 is metal redistribution, the following manner may be used:

[0122] A metal layer is uniformly formed on the first surface of the first substrate 106 by sputtering, evaporation and metal thickening processes; wherein the metal layer may include but is not limited to a Ti / Cu layer or an Al layer; the Ti / Cu layer includes a Ti layer and a Cu layer sequentially arranged along the thickness direction;

[0123] The photoresist is exposed and developed on the surface of the metal layer to form a circuit surface with photoresist retained, and the remaining part without photoresist protection is removed by wet etching to form a first conductive redistribution wiring 111 on the inner surface of the first slot structure, and the first conductive redistribution wiring 111 is led out from the top opening of the first slot structure.

[0124] Furthermore, before step 3, it can also include: coating a first insulating layer 110 on the first surface of the first substrate 106 having the first slot structure formed thereon, and opening the first insulating layer 110 above the second electrode 107 so that the first insulating layer 110 is arranged between the first conductive redistribution wiring 111 and the inner surface of the first slot structure.

[0125] It should be noted that the first insulating layer 110 in this embodiment serves as an insulation between the subsequent first conductive redistribution wiring 111 and the first substrate 106 . This step opens the first insulating layer 110 above the second electrode 107 to prepare for the subsequent first conductive redistribution wiring 111 .

[0126] The present embodiment does not limit the specific type of the first insulating layer 110, and the first insulating layer 110 can be any insulating material. Further, the first insulating layer 110 can be a photoresist material, and accordingly, the first insulating layer 110 above the second electrode 107 can be opened by exposure, development, and dielectric layer etching.

[0127] Furthermore, after step 3, the method may further include: coating a first solder resist package 112 on the first surface of the first substrate 106 after the first conductive redistribution line 111 is formed, and forming a plurality of first through holes in the first solder resist package 112 .

[0128] It should be noted that the first solder resist package 112 in this embodiment can prevent oxidation, scratches / contamination and other abnormalities on the surface of the first conductive redistribution line 111, thereby enhancing product reliability.

[0129] This embodiment does not limit the specific method of forming the first through holes, and multiple first through holes can be formed in the first solder resist package 112 by exposure and development of photoresist characteristics, but is not limited to it. It should be noted that the first through holes penetrate the first solder resist package 112 along the thickness direction, and the surface of the first conductive redistribution 111 will be exposed, and the exposed area can be used as a pad electrically connected to the LED chip 123.

[0130] Step 4: After forming the first conductive redistribution wiring 111 , a single first substrate 106 having a pair of second electrodes 107 is separated from the first substrate 106 .

[0131] It should be noted that the purpose of this step in the present embodiment is to separate a single first substrate 106 having a pair of second electrodes 107 on the first substrate 106 , so as to facilitate subsequent module processing and application.

[0132] This embodiment does not limit the specific method of separating a single first substrate 106 , and may be, but is not limited to, by laser, hidden cutting, or knife wheel cutting, etc., to have a pair of second electrodes 107 .

[0133] This embodiment does not limit the specific method of preparing the second substrate 113, and the following methods may be used but are not limited to:

[0134] Two third electrodes 114 are arranged on the second surface of the second substrate 113, and two second slot structures are arranged in the second substrate 113, a second conductive redistribution 118 is arranged on the inner surface of the second slot structure, and a second seed layer 120 and a second conductive bump 121 are arranged in sequence on one end surface of the second conductive redistribution 118; the two second slot structures are arranged on both sides of the driving chip respectively; the second conductive redistribution 118 is led out from the top opening of the first slot structure, and the final second substrate 113 is obtained;

[0135] Correspondingly, one end of the second conductive redistribution wiring 118 is electrically connected to the first electrode 102 one by one, and the other end is electrically connected to the second surface of the first substrate 106 through the second conductive bump 121; the second conductive redistribution wiring 118 is electrically connected to the third electrode 114 one by one through the bottom opening of the second slot structure.

[0136] It should be noted that the specific method of preparing the third electrode 114, the second slot structure, the second conductive redistribution 118, the second insulating layer 117 and the second solder resist encapsulation 119 in the second substrate 113 of this embodiment, as well as the specific method of bonding the second glass 116 and the specific type of the second temporary bonding material 115 used, can all refer to the specific method of preparing the second electrode 107, the first slot structure, the first conductive redistribution 111, the first insulating layer 110 and the first solder resist encapsulation 112 in the first substrate 106, as well as the specific method of bonding the first glass 109 and the specific type of the first temporary bonding material 108 used, which will not be repeated here. The specific method of preparing the second seed layer 120 and the second conductive bump 121 in the second substrate 113 of this embodiment can refer to the specific method of preparing the first seed layer 103 and the first conductive bump 105 in the driver chip, which will not be repeated here.

[0137] S102: Disposing a driving chip on the first surface of the second substrate, so that both the two first electrodes are electrically connected to the first surface of the second substrate.

[0138] This embodiment does not limit the specific method of arranging the driver chip, and can be but not limited to the following method: the driver chip is flip-chip bonded to the first surface of the second substrate 113. The specific process is:

[0139] Apply soldering flux to the flip-chip region of the first surface of the second substrate 113 (i.e., the surface of one end of the second conductive redistribution 118), or dip the flip-chip region of the driver chip (i.e., the surface of the first conductive bump 105) into soldering flux;

[0140] Align the first conductive bump 105 (which may be spherical) of the driver chip with the first surface of the second substrate 113 and then mount the chip;

[0141] The driver chip and the second substrate 113 after mounting are vacuum reflow soldered and cleaned.

[0142] S103: The first substrate is arranged on a side of the driving chip away from the second substrate, so that the first surfaces of the second substrates on both sides of the driving chip are electrically connected to the second surface of the first substrate, and the second surface of the first substrate is electrically connected to the first surface of the first substrate; the first surface of the first substrate is the surface away from the driving chip; the second surface of the first substrate is the surface close to the driving chip.

[0143] This embodiment does not limit the specific method of setting the first substrate 106, and can be but not limited to the following method: the first substrate 106 and the first surface of the second substrate 113 are flip-chip bonded. The specific process is:

[0144] Apply soldering flux to the flip-chip region of the first surface of the second substrate 113 (i.e., the surface of the second conductive bump 121), or dip the flip-chip region of the first substrate 106 (i.e., the surface of the second electrode 107) into soldering flux;

[0145] Align the second electrode 107 of the second substrate 113 with the second conductive bump 121 (which may be spherical) of the second substrate 113 and then perform chip bonding;

[0146] The first substrate 106 and the second substrate 113 after chip bonding are vacuum reflow soldered and cleaned.

[0147] Furthermore, in this embodiment, after step S103, wafer-level plastic encapsulation technology can be used to inject glue on the side of the second conductive bump 121 away from the driver chip to form a plastic encapsulation glue 122; the height of the plastic encapsulation glue 122 is equal to the spacing between the first substrate 106 and the second substrate 113, and is arranged along the circumferential direction. It should be noted that the plastic encapsulation glue 122 in this embodiment can put the driver chip in a vacuum-tight environment, greatly improving the reliability of the product.

[0148] S104: Disposing an LED chip on the first surface of the first substrate, so that the LED chip is electrically connected to the first surface of the first substrate, to obtain an LED packaging structure.

[0149] The present embodiment does not limit the specific method of disposing the LED chip 123, and may be, but is not limited to, the following method: attaching the LED chip 123 to the surface of the first conductive redistribution wiring 111 (which may be the surface of the first conductive redistribution wiring 111 exposed at the first through hole position).

[0150] Based on the above embodiments, the present invention can prepare the above LED packaging structure, so it also has the above beneficial effects.

[0151] The following is a specific example to illustrate the above LED packaging process. Please refer to Figure 1 , Figures 3 to 22 , the process is as follows:

[0152] 1. Preparation of driver chip:

[0153] In the first step, a first seed layer 103 is formed on the surface of the existing driver wafer 101 by sputtering, evaporation or other processes. In this embodiment, the first seed layer 103 is a Ti / Cu seed layer, and its structure is as follows: Figure 3 shown.

[0154] In the second step, the first seed layer 103 is patterned by photolithography coating 104 and the like, so as to prepare for the subsequent electroplating process of the first conductive bump 105. The structure is as follows: Figure 4 shown.

[0155] In the third step, the first conductive bump 105 is made by electroplating copper, nickel, tin, silver or other metals. In this embodiment, the first conductive bump 105 is a metal bump, and its structure is as follows: Figure 5 shown.

[0156] In the fourth step, after the first conductive bump 105 is completed, the photolithography film 104 of the second step is removed, and then wet etching is performed to remove the exposed first seed layer 103, so as to prepare for the subsequent reflow soldering and separation of the single driver chip. Figure 6 shown.

[0157] The fifth step is to change the first conductive bump 105 into a spherical shape by reflow soldering to prepare for subsequent flip-chip soldering with the second substrate 113. Figure 7 shown.

[0158] Step 6: Thinning the driver wafer 101 by grinding. Figure 8 shown.

[0159] The seventh step is to separate the individual driver chips through laser, hidden cutting or knife wheel cutting.

[0160] 2. Preparation of the first substrate 106:

[0161] In the first step, in this embodiment, the first substrate 106 is a silicon substrate, and a metal wiring layer is implemented on the first substrate 106 using wafer-level packaging technology. The structure is as follows: Fig. 9 shown.

[0162] In the second step, a removable first temporary bonding material 108 is coated on the surface of the first glass 109. In this embodiment, the first temporary bonding material 108 is a temporary bonding adhesive. The first glass 109 is bonded to the second surface of the first substrate 106 by using the viscosity of the temporary bonding adhesive and parameters such as pressure, temperature and UV characteristics. The structure is as follows: Fig.10 Show.

[0163] The third step is to thin the first substrate 106, which can be processed by mechanical grinding with a diamond wheel, or mechanical chemical grinding and polishing, or plasma dry etching, or wet etching with a fluorine-containing solution. Preferably, the method of mechanical grinding with a diamond wheel and then plasma dry etching is used, and its structure is as follows: Fig.11 shown.

[0164] The fourth step is to etch a first slot structure on the first surface of the thinned first substrate 106: the preferred and most mature method is to use photolithography and dry etching to etch away the excess first substrate 106, etch out grooves and through holes, and form a first slot structure. The specific process is: use a photoresist material (such as photoresist) with photoresist properties to cover the first surface of the first substrate 106; then use a mask with a special pattern to perform photosensitive treatment under light of a specific wavelength, and then use chemical agents for development to produce a photoresist pattern; then use a dry etching process to etch the excess first substrate 106; wherein, the portion not covered by the photoresist will be removed by the active fluorine ion etching reaction, thereby achieving the purpose of removing the excess first substrate 106; wet etching process can also be used instead of dry etching process; after the first substrate 106 is etched, the protective layer photoresist on the first surface of the first substrate 106 must also be removed; finally, the first surface of the first substrate 106 is cleaned, and its structure after etching is as follows Fig.12 shown.

[0165] In the fifth step, a first insulating layer 110 is coated on the first surface of the first substrate 106 formed with the first slot structure, which plays an insulating role between the subsequent first conductive redistribution wiring 111 and the first substrate 106. At the same time, the first insulating layer 110 is also a layer of photoresist material. By exposure, development and dielectric layer etching, the first insulating layer 110 above the second electrode 107 is opened to pave the subsequent first conductive redistribution wiring 111. Its structure is as follows: Fig.13 shown.

[0166] In the sixth step, a metal layer is uniformly formed on the first surface of the first substrate 106 by sputtering, evaporation and metal thickening processes, and then the surface of the metal layer is exposed and developed by photoresist to form a circuit surface with photoresist retained, and the remaining part without photoresist protection is removed by wet etching, and finally connected with the second electrode 107 on the second surface, and a first conductive redistribution wiring 111 is formed on the inner surface of the first slot structure, and the first conductive redistribution wiring 111 is led out from the top opening of the first slot structure, and its structure is as shown in FIG. Fig.14 shown.

[0167] Step 7: A plurality of first through holes are provided in the first solder resist package 112. At the same time, a plurality of first through holes are formed in the first solder resist package 112 by means of photoresist characteristic exposure and development, thereby opening the pad position on the surface of the first conductive redistribution wiring 111. The structure is as follows: Fig.15 shown.

[0168] The eighth step is to debond and separate the first glass 109 from the first substrate 106. According to the characteristics of the temporary bonding adhesive, the separation can be carried out by heating, laser or UV photolysis. The structure is as follows: Fig.16 shown.

[0169] In the ninth step, the first substrate 106 having a pair of second electrodes 107 is separated by laser, hidden cutting or wheel cutting.

[0170] 3. Preparation of the second substrate 113:

[0171] In the first step, the first to seventh steps of the first substrate 106 process are performed on the second substrate 113. The structure is as follows: Fig.17 shown.

[0172] The second step is Fig.17 The first to fifth steps of the driver chip are performed on the structure shown in FIG. Fig.18 shown.

[0173] The third step is to debond and separate the second glass 116 from the second substrate 113. According to the characteristics of the temporary bonding adhesive, the separation can be carried out by heating, laser or UV photolysis. The structure is as follows: Fig.19 shown.

[0174] In the fourth step, the second substrate 113 having a pair of third electrodes 114 is separated by laser, hidden cutting or wheel cutting.

[0175] 4. Stacked packaging:

[0176] The first step is to flip-chip solder the driver chip to the first surface of the second substrate 113. The specific process is: apply solder flux to the flip-chip soldering area on the first surface of the second substrate 113 (i.e., the surface of one end of the second conductive redistribution 118), or dip the flip-chip soldering area of ​​the driver chip (i.e., the surface of the first conductive bump 105) into solder flux; align the first conductive bump 105 (which can be spherical) of the driver chip with the first surface of the second substrate 113 and then mount the chip; vacuum reflow solder the preliminarily formed assembly and clean it. Its structure is as follows Fig. 20 shown.

[0177] The second step is to flip-chip solder the first substrate 106 and the first surface of the second substrate 113. The specific process is: apply solder flux to the flip-chip soldering area (i.e., the surface of the second conductive bump 121) on the first surface of the second substrate 113, or dip the solder flux into the flip-chip soldering area (i.e., the surface of the second electrode 107) of the first substrate 106; align the second electrode 107 of the second substrate 113 with the second conductive bump 121 (which can be spherical) of the second substrate 113 and then perform chip mounting; vacuum reflow soldering and cleaning of the initially formed assembly, the structure of which is as follows: Fig.21 As shown, in this embodiment, the second electrode 107 and the second conductive bump 121 are made of the same metal material, so the second electrode 107 is not marked in the figure.

[0178] In the third step, the wafer-level plastic packaging technology is used to inject glue around the structure to form a plastic packaging glue 122, the structure of which is as follows: Fig. 22 shown.

[0179] In the fourth step, the LED chip 123 is attached to the surface of the first conductive redistribution wiring 111 (which may be the surface of the first conductive redistribution wiring 111 exposed at the first through hole position) to complete the full process packaging. The structure is as follows: Figure 1 shown.

[0180] The principles and implementation methods of the present invention are described herein using specific examples, and the various embodiments are in a progressive relationship. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. For those of ordinary skill in the art, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the present invention.

[0181] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

Claims

1. An LED packaging structure, characterized in that: include: A first substrate, a second substrate, a driver chip and a plurality of LED chips; The driving chip is disposed on the first surface of the second substrate; two first electrodes are disposed on the surface of the driving chip; and both of the two first electrodes are electrically connected to the first surface of the second substrate; The first substrate is arranged on a side of the driving chip away from the second substrate; the first surfaces of the second substrates on both sides of the driving chip are electrically connected to the second surface of the first substrate; the second surface of the first substrate is electrically connected to the first surface of the first substrate; The first surface of the first substrate is a surface facing away from the driving chip; The second surface of the first substrate is a surface close to the driving chip; The LED chip is disposed on the first surface of the first substrate and is electrically connected to the first surface of the first substrate.

2. The LED packaging structure according to claim 1, characterized in that: A first seed layer is disposed on the surfaces of the two first electrodes; a first conductive bump is disposed on the surface of the first seed layer; and the first conductive bump is electrically connected to the first surface of the second substrate.

3. The LED packaging structure according to claim 1, characterized in that: The second surface of the first substrate is provided with two second electrodes; the first surfaces of the second substrate on both sides of the driving chip are electrically connected to the two second electrodes one by one; Two first slot structures are arranged in the first substrate; the two first slot structures are arranged on both sides of the driving chip respectively; The inner surface of the first slot structure is provided with a first conductive redistribution wiring; The first conductive redistribution wiring is led out from the top opening of the first slot structure and is electrically connected to the LED chip; the first conductive redistribution wiring is electrically connected to the second electrodes one by one through the bottom opening of the first slot structure.

4. The LED packaging structure according to claim 3, characterized in that: A first insulating layer is provided between the first conductive redistribution wiring and the inner surface of the first slot structure; And / or, a first solder resist package is provided on a surface of the first conductive redistribution pattern away from the first slot structure; and a plurality of first through holes are provided in the first solder resist package; The first conductive redistribution wiring is led out from the top opening of the first slot structure and is electrically connected to the LED chip through the first through hole.

5. The LED packaging structure according to any one of claims 1 to 4, characterized in that: The second surface of the second substrate is provided with two third electrodes; Two second slot structures are arranged in the second substrate; the two second slot structures are arranged on both sides of the driving chip respectively; The inner surface of the second slot structure is provided with a second conductive redistribution wiring; The second conductive redistribution wiring is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode one by one, and the other end is electrically connected to the second surface of the first substrate through a second conductive bump; a second seed layer is arranged between the second conductive bump and the second conductive redistribution wiring; the second conductive redistribution wiring is electrically connected to the third electrode one by one through the bottom opening of the second slot structure.

6. The LED packaging structure according to claim 5, characterized in that: A second insulating layer is provided between the second conductive redistribution wiring and the inner surface of the second slot structure; And / or, a second solder resist package is provided on a surface of the second conductive redistribution pattern away from the second slot structure; and four second through holes are provided in the second solder resist package; The second conductive redistribution wiring is led out from the top opening of the second slot structure, and one end is electrically connected to the first electrode one by one through the second through hole, and the other end is electrically connected to the second surface of the first substrate through the second conductive bump; the second conductive bump is located in the second through hole.

7. The LED packaging structure according to claim 5, characterized in that: Also includes: Plastic sealant; the plastic sealant is located on a side of the second conductive bump away from the driver chip and is arranged along the circumferential direction; the height of the plastic sealant is equal to the distance between the first substrate and the second substrate.

8. A LED packaging method, characterized in that: include: A driving chip, a first substrate and a second substrate are prepared; two first electrodes are arranged on the surface of the driving chip; The driving chip is disposed on the first surface of the second substrate so that both of the two first electrodes are electrically connected to the first surface of the second substrate; The first substrate is arranged on a side of the driving chip away from the second substrate, so that the first surfaces of the second substrate on both sides of the driving chip are electrically connected to the second surface of the first substrate, and the second surface of the first substrate is electrically connected to the first surface of the first substrate; The first surface of the first substrate is a surface facing away from the driving chip; The second surface of the first substrate is a surface close to the driving chip; An LED chip is disposed on the first surface of the first substrate, and the LED chip is electrically connected to the first surface of the first substrate to obtain an LED packaging structure.

9. The LED packaging method according to claim 8, characterized in that: The method of preparing the driving chip, the first substrate and the second substrate comprises: Arranging a first seed layer on the surfaces of the two first electrodes, and arranging a first conductive bump on the surface of the first seed layer, to obtain the final driving chip; Correspondingly, the first conductive bump is electrically connected to the first surface of the second substrate.

10. The LED packaging method according to claim 8, characterized in that: The method of preparing the driving chip, the first substrate and the second substrate comprises: Two second electrodes are arranged on the second surface of the first substrate, two first slot structures are arranged in the first substrate, and first conductive redistribution wiring is arranged on the inner surface of the first slot structure; the two first slot structures are arranged on both sides of the driving chip respectively; the first conductive redistribution wiring is led out from the top opening of the first slot structure, and the final second substrate is obtained; Correspondingly, the first surface of the second substrate on both sides of the driving chip is electrically connected to the two second electrodes one by one; the first conductive redistribution is electrically connected to the second electrodes one by one through the bottom opening of the first slot structure; and the LED chip is electrically connected to the first conductive redistribution.

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