WO2015000276A1 - Thin film led device and manufacturing method thereof - Google Patents

Abstract

A thin film LED device and manufacturing method thereof are provided. The LED device comprises a slice-type circuit board (1), a flip structure LED chip (2) without gold wires and a light transmission protecting film (3). Chip electrodes (21, 22) of the LED chip (2) are fixed on the slice-type board by eutectic welding way. An electric connection without gold wire bonding is achieved. The light transmission protecting film (3) covers on the surface of the chip (2) and the circuit board (1). Electrodes of the LED device are positioned at the bottom of the device for realizing the surface mount technology easily. The thickness of the LED device is between 0.25-0.6 mm. The LED device has the advantages of thin thickness, small size, large light-emitting angle, high light efficiency, high reliability, simple manufacturing process, low cost and the like, is suitable for high-power and common-power LED packaging, and can be widely applied in the fields of illumination, display and the like.

Description

 Thin film type LED device and manufacturing method thereof

Technical field

The invention relates to a thin film type LED device and a manufacturing method thereof, in particular to a structure of an LED device and a preparation method thereof, which belong to the field of semiconductor device manufacturing.

Background technique

LED light source has become a fourth-generation light source with its high luminous efficiency, energy saving, environmental protection, long life and short response time. It has gradually replaced traditional light sources and has shown great potential in the market. Especially for LED light sources, the amount of use in the field of lighting is very large. Driven by the emergence of emerging application markets, the LED market has grown rapidly in recent years. The demand for LEDs in the market has risen sharply, especially for small size, large light-emitting areas, and thin devices. In lighting products, many LED devices have to meet the requirements of light distribution due to the need for secondary lenses. The devices are faced with lens compression devices caused by assembly errors, resulting in device failures, etc., and backlights for LED devices, such as flat panel TV backlights. The source saves about 48% of power compared with the traditional cold cathode ray tube, and its color reproduction range can reach 105% or even 120% of the National Television System Committee (NTSC) standard, which has great promotion and application value. At present, the ultra-thin LED TV has become the mainstream trend, so the demand for ultra-thin LED devices is very urgent. At the same time, whether it is a direct-lit backlight or a side-in backlight, the device also has a light-shielded panel. The possibility of the gold line.

In addition, power-type LED devices typically require expensive molds for one-shot molding of lenses, and the cost of product modification and upgrades is extremely high. At the same time, the plastic packaging process requires extremely sophisticated and sophisticated equipment. The number of integrated devices for a single LED package substrate is limited by the size of the mold and the size of the special fixture. In the face of increasing market demand, the manufacturing methods limited by molds, fixtures and equipment will increasingly deviate from actual needs. In order to further improve production efficiency, new device structures and manufacturing methods are urgently needed.

Faced with the above problems, the new ultra-thin device has become a trend. At the same time, the reliability of the gold-free package structure is higher, and it will become the development direction of LED devices in the future. The invention is directed to the above technical defects and the development trend of the LED lighting market, and proposes a thin film type LED device and a manufacturing method thereof, the device is ultra-thin, the thickness range can be between 0.25-0.6 mm, and the gold-free wire flipping is adopted at the same time. The structure is packaged with high reliability and high luminous angle. The outer surface molding material adopts a self-proclaimed process. It does not need to use molds and complicated injection molding, and the hot pressing function equipment is simple and efficient in manufacturing method, and is very suitable for industrialization and backlighting. The promotion of lighting and other fields has an extremely broad market space.

Summary of the invention

In view of the above technical problems, the present invention aims to solve the above technical problems at least to some extent.

A primary object of the present invention is to provide a thin film type LED device. Another object of the present invention is to provide a method of fabricating a thin film type LED device.

In order to achieve the above object, a first aspect of the present invention provides a thin film type LED device, comprising a sheet type line bracket, a gold line-free flip-chip LED chip and a transparent protective film, the LED chip being positive The negative electrode is bonded to the upper surface circuit layer of the sheet-type line support by eutectic soldering, and the lower surface circuit layer of the thin-type line support is connected to the positive and negative circuit of the LED chip by connecting the upper surface circuit layer through the line. The light-transmissive protective film is tightly covered on the top and the periphery of the LED chip and on the upper surface wiring layer of the sheet-type line support.

Further, the sheet type line support is a double-layer printed circuit board having a circuit layer, and the upper surface circuit layer and the lower surface circuit layer are respectively provided with an insulating groove for blocking the circuit layer from being a positive electrode and a negative electrode, wherein the upper surface line The positive electrode of the layer is connected to the positive electrode of the LED chip, the negative electrode is connected to the negative electrode of the LED chip, the positive electrode and the positive electrode of the upper surface circuit layer and the lower surface circuit layer, and the negative electrode and the negative electrode are connected to each other;

Further, the surface of the upper surface wiring layer is etched or die-cut with a cross-shaped LED chip mounting mark.

Further, the lower surface wiring layer is further provided with an auxiliary pad for enhancing fixation and heat conduction.

Further, the thickness of the sheet-type line support is less than or equal to 0.2 mm, and the thickness of the upper surface circuit layer and the lower surface circuit layer is less than or equal to 0.1 mm.

Further, the light transmissive protective film is a polymer organic film sheet having a thickness of 0.1 mm or less.

Further, the light transmissive protective film is filled with scattering powder or yellow phosphor particles, and monochromatic light or mixed color light can be realized.

Compared with the conventional package structure, the thin film type LED device proposed by the invention is thinner, has a larger illumination angle, and has no gold wire in the conventional packaging process, and the device reliability is greatly increased. In addition, the plastic lens mold is compared with the conventional packaging process. And the equipment is expensive, resulting in an increase in product cost. The technical method proposed by the invention can greatly reduce the equipment input and reduce the product cost. In addition, the thin film type LED device electrode of the invention is located at the bottom of the device and belongs to the surface mount type device structure. It is suitable for reflow soldering and automated test braiding process, and is more suitable for downstream automatic patch installation and assembly of LED industry chain.

A second aspect of the present invention provides a method of fabricating a thin film type LED device, comprising the steps of:

S1. A flux on a center point of each of the bracket units of the sheet-type circuit substrate having the positioning holes at the edge, and the flux area is equivalent to the bottom electrode area of the LED chip;

S2, the LED chip is placed on the thin-type circuit substrate with the flux; the LED chip is placed according to the LED chip placement mark;

S3. placing a thin-film circuit substrate on which the LED chip is placed in a reflow furnace for eutectic solidification;

S4, uniformly spraying a layer of liquid adhesive on the eutectic solid crystal thin-film circuit substrate, laying a transparent protective film, and transferring it into a vacuum chamber, and placing it on the lower mold of the vacuum chamber to make the positioning hole and the lower mold The positioning pins are matched;

S5, the vacuum chamber is vacuum degassed by a vacuum pump, and when the vacuum pressure reaches 10-2 Pa or less, the upper mold frame is heated to 140-160 ° C and pressed down to realize the frame sealing and bonding of the transparent protective film and the sheet type circuit substrate. ;

S6, lifting up the upper mold, restoring the air pressure in the vacuum chamber, and taking out the sheet type circuit substrate with the transparent protective film;

S7, the sheet-type circuit substrate with a transparent protective film is placed in an oven and baked at a temperature of 140-160 ° C for 2-3 hours;

S8. The thin-film circuit substrate after curing is diced and divided along the dicing reference line to form a single thin film type LED device.

Further, the liquid adhesive is a homogenous material and the transparent protective film is cured at 140-160 ° C to achieve bonding and sealing of the transparent protective film and the sheet-type circuit substrate.

Further, the upper mold is a rectangular frame having a heating rod, and the length and width of the inner and outer sides are the same as or slightly larger than the frame size of the sheet-type circuit substrate, and the upper mold pressing operation is controlled by the hydraulic cylinder.

The invention relates to a method for manufacturing a thin film type LED device which can be carried out by using conventional technical equipment. The invention is innovative in that the device molding process is improved, and the LED device structure proposed by the invention is free of gold wires, and the LED chip is flipped. The structure has strong anti-pressure and impact resistance, and the transparent protective film can be adhered to the surface of the LED chip by vacuum adsorption and hot pressing, thereby reducing the use of special plastic sealing molds and equipment. The utility model can greatly reduce the manufacturing cost of the device and improve the production efficiency. The structural device can replace the bracket type device of the traditional PPA and PLCC materials, and is suitable for various fields such as backlight, indoor and outdoor lighting, and has wide application space and considerable industrialization prospect. In addition, the thin film type LED device proposed by the invention has the characteristics of ultra-thin, large light-emitting area and low thermal resistance, and the overall thickness of the device can be controlled at 0.25-0.6 mm, and the chip is heated due to the flip-chip structure and package form. The area is closer to the heat dissipation path and the thermal resistance is low, up to 4-6K/W.

 DRAWINGS

 Figure 1 is a cross-sectional view showing the structure of a thin film type LED device.

 Figure 2 shows a top view of the structure of a thin film LED device.

 Figure 3 is a top view of a substrate containing multiple thin film LED devices.

 Figure 4 is a schematic diagram of the degassing step of the vacuum chamber.

 Figure 5 is a schematic cross-sectional view of the lower pressure seal of the mold after the degassing is completed.

 Figure 6 is a schematic cross-sectional view of the LED substrate after the vacuum chamber is taken out.

 The figure shows: 1--sheet type line bracket; 11- upper surface circuit layer; 12- lower surface circuit layer; 13-LED Chip mounting mark; 14- auxiliary pad; 2- LED chip; 21- LED chip positive electrode; 22- LED chip negative electrode; 3- light transparent protective film; 4-sheet type circuit substrate; 41- Scratch reference line; 42- Locating pin hole; 5- Liquid adhesive; 6- Vacuum chamber; 7- Vacuum pump; 8-Mold; 81- Upper mold; 82- Lower mold; 83- Position the pin.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Embodiment 1:

 This embodiment provides a thin film type LED device. The present invention will now be described in detail with reference to FIGS. 1 and 2.

 1 is a cross-sectional view showing the structure of a thin film type LED device according to the present invention, as shown in the drawing,

A thin film type LED device comprises a sheet type line support 1, an LED chip 2 with no gold wire flip-chip structure and a transparent protective film 3, the LED chip 2 has a thickness of 0.1 mm, and the positive and negative electrodes of the LED chip 2 Bonded to the upper surface circuit layer 11 of the sheet-type line support 1 by eutectic soldering, the lower surface circuit layer 12 of the sheet-type line support 1 is connected to the positive and negative circuits of the LED chip 2 through the upper surface circuit layer In connection, the light-transmitting protective film 3 closely covers the top and the periphery of the LED chip 2 and the upper surface wiring layer 11 of the sheet-type line holder 1.

Further, the sheet-type line support 1 is a two-layer printed circuit board having a circuit layer, and the upper surface circuit layer 11 and the lower surface circuit layer 12 are each provided with an insulating groove for blocking the circuit layer from the positive electrode and the negative electrode, wherein The positive electrode of the upper surface wiring layer 11 is connected to the positive electrode 21 of the LED chip, the negative electrode is connected to the negative electrode 22 of the LED chip, and the positive electrode and the positive electrode of the upper surface wiring layer 11 and the lower surface wiring layer 12 are connected to each other, and the negative electrode and the negative electrode are connected to each other.

Further, the surface of the upper surface wiring layer 11 is etched or die-cut with a cross-shaped LED chip mounting mark 13.

Further, the lower surface wiring layer 12 is also provided with an auxiliary pad 14 for enhancing fixation and heat conduction.

Further, the thickness of the sheet-type line support 1 is 0.15 mm, and the thickness of the upper surface wiring layer 11 and the lower surface wiring layer 12 are both 0.025 mm.

Further, the light-transmitting protective film 3 is a polymer organic film sheet having a thickness of 0.1 mm.

Further, the light transmissive protective film 3 is internally filled with scattering powder or yellow phosphor particles, and monochromatic light or mixed color light can be realized.

The LED device illumination area is located on top of the device.

Embodiment 2:

This embodiment provides a method for manufacturing a thin film type LED device. The manufacturing method proposed by the present invention will be further described and illustrated in conjunction with FIGS. 3, 4 and 5.

A method of fabricating a thin film LED device, comprising the steps of:

S1, a flux on a center point of each of the bracket units of the sheet-type circuit substrate 4 having the positioning holes 42 at the edge, the flux area is equivalent to the bottom electrode area of the LED chip 2, and the flux is a rosin-like colloid;

S2, the LED chip 2 is placed on the thin-type circuit substrate 4 with the flux, and the LED chip 2 is positioned according to the LED chip mounting mark 13 when the LED chip 2 is placed;

S3, placing the sheet-type circuit substrate 4 on which the LED chip 2 is placed in a reflow furnace for eutectic solidification;

S4, uniformly spraying a layer of liquid adhesive agent 5 on the eutectic solid crystal chip substrate 4, laminating a transparent protective film 3, and transferring it into the vacuum chamber 6, and placing it under the mold 8 inside the vacuum chamber 6. On the mold 82, the positioning hole 42 is matched with the positioning pin 83 of the lower mold 82;

S5, the vacuum chamber 6 is vacuum degassed by the vacuum pump 7, and when the vacuum pressure reaches 10-2 Pa or less, the frame of the upper mold 81 is heated to 140 ° C and pressed down to realize the frame sealing of the transparent protective film 3 and the sheet type circuit substrate 4. And bonding;

S6, lift up the upper mold 81, restore the air pressure in the vacuum chamber 6, take out the sheet-type circuit substrate 4 with a light-transmissive protective film;

S7, the sheet-type circuit substrate 4 with a light-transmissive protective film is placed in an oven and baked at a temperature of 140 ° C for 3 hours;

S8. The sheet-type circuit substrate 4 which has been cured after baking is diced and divided along the dicing reference line 41 to form a single film type LED device.

Further, the liquid adhesive 5 and the light-transmitting protective film are homogenous materials, and are cured at 140-160 ° C to bond and seal the light-transmitting protective film 3 and the sheet-type circuit substrate 4.

Further, the upper mold 81 is a rectangular frame having a heating rod, and the length and width of the inner and outer sides thereof are the same as or slightly larger than the frame size of the sheet-type circuit substrate 4, and the pressing operation of the upper mold 81 is controlled by a hydraulic cylinder.

The positioning pin 42 is lower in height than the thickness of the sheet type wiring substrate 4.

Embodiment 3:

This embodiment provides a method for manufacturing a thin film type LED device. The manufacturing method proposed by the present invention will be further described and illustrated in conjunction with FIG. 3, FIG. 4 and FIG.

 A method of fabricating a thin film LED device, comprising the steps of:

S1, a flux on a center point of each of the bracket units of the sheet-type circuit substrate 4 having the positioning holes 42 at the edge, the flux area is equivalent to the bottom electrode area of the LED chip 2, and the flux is a rosin-like colloid;

S2, the LED chip 2 is placed on the thin-type circuit substrate 4 with the flux, and the LED chip 2 is positioned according to the LED chip mounting mark 13 when the LED chip 2 is placed;

S3, placing the sheet-type circuit substrate 4 on which the LED chip 2 is placed in a reflow furnace for eutectic solidification;

S4, uniformly spraying a layer of liquid adhesive agent 5 on the eutectic solid crystal chip substrate 4, laminating a transparent protective film 3, and transferring it into the vacuum chamber 6, and placing it on the lower mold 82 of the vacuum chamber 6. Aligning the positioning hole 42 with the positioning pin 83 of the lower mold 82;

S5, the vacuum chamber 6 is vacuum degassed by the vacuum pump 7, and when the vacuum pressure reaches 10-2 Pa or less, the frame of the upper mold 81 is heated to 150 ° C and pressed down to realize the frame sealing of the transparent protective film 3 and the sheet type circuit substrate 4. And bonding;

S6, lift up the upper mold 81, restore the air pressure in the vacuum chamber 6, take out the sheet-type circuit substrate 4 with a light-transmissive protective film;

S7, the sheet-type circuit substrate 4 with a light-transmissive protective film is placed in an oven and baked at a temperature of 150 ° C for 2 hours;

S8. The sheet-type circuit substrate 4 which has been cured after baking is diced and divided along the dicing reference line 41 to form a single film type LED device.

Further, the liquid adhesive 5 and the light-transmitting protective film are homogenous materials, and are cured at 140-160 ° C to bond and seal the light-transmitting protective film 3 and the sheet-type circuit substrate 4.

Further, the upper mold 81 is a rectangular frame having a heating rod, and the length and width of the inner and outer sides thereof are the same as or slightly larger than the frame size of the sheet-type circuit substrate 4, and the pressing operation of the upper mold 81 is controlled by a hydraulic cylinder.

The positioning pin 42 is lower in height than the thickness of the sheet type wiring substrate 4.

Embodiment 4:

This embodiment provides a method for manufacturing a thin film type LED device. The manufacturing method proposed by the present invention will be further described and illustrated in conjunction with FIGS. 3, 4 and 5.

A method of fabricating a thin film LED device, comprising the steps of:

S1, a flux on a center point of each of the bracket units of the sheet-type circuit substrate 4 having the positioning holes 42 at the edge, the flux area is equivalent to the bottom electrode area of the LED chip 2, and the flux is a rosin-like colloid;

S2, the LED chip 2 is placed on the thin-type circuit substrate 4 with the flux, and the LED chip 2 is positioned according to the LED chip mounting mark 13 when the LED chip 2 is placed;

S3, placing the sheet-type circuit substrate 4 on which the LED chip 2 is placed in a reflow furnace for eutectic solidification;

S4, uniformly spraying a layer of liquid adhesive agent 5 on the eutectic solid crystal chip substrate 4, laminating a transparent protective film 3, and transferring it into the vacuum chamber 6, and placing it on the lower mold 82 of the vacuum chamber 6. Aligning the positioning hole 42 with the positioning pin 83 of the lower mold 82;

S5, the vacuum chamber 6 is vacuum degassed by the vacuum pump 7, and when the vacuum pressure reaches 10-2 Pa or less, the frame of the upper mold 81 is heated to 160 ° C and pressed down to realize the frame sealing of the transparent protective film 3 and the sheet type circuit substrate 4. And bonding;

S6, lift up the upper mold 81, restore the air pressure in the vacuum chamber 6, take out the sheet-type circuit substrate 4 with a light-transmissive protective film;

S7, the sheet-type circuit substrate 4 with a light-transmissive protective film is placed in an oven and baked at a temperature of 160 ° C for 2 hours;

S8. The sheet-type circuit substrate 4 which has been cured after baking is diced and divided along the dicing reference line 41 to form a single film type LED device.

Further, the liquid adhesive 5 and the light-transmitting protective film are homogenous materials, and are cured at 140-160 ° C to bond and seal the light-transmitting protective film 3 and the sheet-type circuit substrate 4.

Further, the upper mold 81 is a rectangular frame having a heating rod, and the length and width of the inner and outer sides thereof are the same as or slightly larger than the frame size of the sheet-type circuit substrate 4, and the pressing operation of the upper mold 81 is controlled by a hydraulic cylinder.

The positioning pin 42 is lower in height than the thickness of the sheet type wiring substrate 4.

The above-described embodiments of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Other variations or modifications of the various forms may be made by those skilled in the art in light of the above description. There is no need and no way to exhaust all of the implementations. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the invention are intended to be included within the scope of the appended claims.

Claims (10)

A thin film type LED device comprises a sheet type line support (1), a gold wire flip-chip-free LED chip (2) and a light-transmissive protective film (3), characterized in that: the LED chip (2) The positive and negative electrodes are bonded to the upper surface circuit layer (11) of the sheet-type line support (1) by eutectic soldering, and the lower surface circuit layer (12) of the thin-type line support (1) is connected to the upper surface line by a line. The layers (11) are respectively connected to the positive and negative circuits of the LED chip (2), and the transparent protective film (3) closely covers the top and the periphery of the LED chip (2) and the upper surface of the sheet-type line support (1). On the circuit layer (11). The thin film type LED device according to claim 1, wherein said sheet type wiring support (1) is a two-layer printed wiring board having a wiring layer, and an upper surface wiring layer (11) and a lower surface wiring layer ( 12) Each is provided with an insulating groove for blocking the circuit layer from the positive electrode and the negative electrode, wherein the positive electrode of the upper surface circuit layer (11) is connected to the positive electrode (21) of the LED chip, and the negative electrode is connected to the negative electrode (22) of the LED chip. The positive electrode and the positive electrode of the surface wiring layer (11) and the lower surface wiring layer (12) communicate with each other between the negative electrode and the negative electrode. The thin film type LED device according to claim 2, characterized in that the surface of the upper surface wiring layer (11) is etched or die-cut with a cross-shaped LED chip mounting mark (13). A thin film type LED device according to claim 2, wherein said lower surface wiring layer (12) is further provided with an auxiliary pad (14) for enhancing fixation and heat conduction. The thin film type LED device according to claim 1, wherein the thickness of the sheet type wiring support (1) is 0.1 mm or less, and the thickness of the upper surface wiring layer (11) and the lower surface wiring layer (12) are smaller than Equal to 0.1mm. The thin film type LED device according to claim 1, wherein the light-transmitting protective film (3) is a polymer organic film sheet having a thickness of 0.1 mm or less. The thin film type LED device according to claim 1, wherein the light transmissive protective film (3) is internally filled with scattering powder or yellow phosphor particles, and monochromatic light or mixed color light can be realized. A method of manufacturing a thin film type LED device according to any of claims 1-7, comprising the steps of: S1, a flux on a center point of each of the bracket units of the sheet-type circuit substrate (4) having positioning holes (42) at the edges, and the flux area is equivalent to the bottom electrode area of the LED chip (2); S2, the LED chip (2) is placed on the thin-type circuit substrate (4) with the flux, and the LED chip (2) is positioned according to the LED chip mounting mark (13); S3, placing the thin-film circuit board (4) on which the LED chip is placed in a reflow furnace for eutectic solidification; S4. uniformly spray a layer of liquid adhesive (5) on the eutectic solid crystal chip substrate (4), cover a transparent protective film (3), and transfer it to the vacuum chamber (6) and place it. a vacuum chamber (6) is disposed on the inner lower mold (82) to match the positioning hole (42) with the positioning pin (83) of the lower mold (82); S5, the vacuum chamber (6) is vacuum degassed by a vacuum pump (7), and when the vacuum pressure reaches 10-2 Pa or less, the upper mold (81) frame is heated to 140-160 ° C and pressed down to realize a transparent protective film (3). ) sealing and bonding with the frame of the sheet-type circuit substrate (4); S6, lifting up the upper mold (81), restoring the air pressure in the vacuum chamber (6), and taking out the sheet type circuit substrate (4) with the transparent protective film; S7. The sheet-type circuit substrate (4) with a light-transmissive protective film is placed in an oven and baked at a temperature of 140-160 ° C for 2-3 hours. The method according to claim 7, wherein said impregnation die has at least three contact godet rollers and three pairs of non-contact godet rollers, and the glass fiber bundles are surrounded by a wrap angle of not more than 90 degrees. The godet roller and the slit passing through the pair of non-contact godet rollers. The method for manufacturing a thin film type LED device according to claim 8, wherein the liquid adhesive (5) and the light transmissive protective film (3) are homogenous materials, and are cured at 140-160 ° C to achieve transparency. Bonding and sealing of the photoprotective film (3) and the sheet type wiring substrate (4). A method of manufacturing a thin film type LED device according to claim 9, wherein said upper mold (81) is a rectangular frame having a heating rod, and a length and a width of the inner and outer sides thereof and a sheet type wiring substrate (1) The frame size is the same or slightly larger, and the pressing action of the upper mold (81) is controlled by the hydraulic cylinder.

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