TW595015B - Bare-die type LED - Google Patents

Abstract

A bare-die type LED is disclosed, witch is to fabricate the LED die directly into SMD structure for use without the packaging process. Sapphire crystal is used as the best natural package substrate for GaN LED die. The electrode surface is fabricated into optically reflective surface by flip-chip technology. Electroplate an SiO2 passivation film layer, and fabricate the electrode bump, so as to fabricate micro lenses or nano dots, nano rods on the substrate surface for increasing the light output. The SMD bare-die type LED is then completed without the package process to connect the bare-die type LED with the circuit board. Its features are saving the cost, high yield rate, good heat dissipation, easy minimization, and it can function as a high-power light-emitting device.

Description

595015 Schematic illustrations _ * 5. Schematic descriptions of Schematics / parts, '' The diagram is the structure diagram of the traditional surface-adhesive light-emitting diode (SMD LED) 々 (circuit board type) · The diagram = The basic structure diagram of the bare-crystal light-emitting diode of the present invention (1) The third diagram is the basic structure diagram of the bare-crystal light-emitting diode of the present invention (ii) The f-picture is the basic structure of the bare-crystal light-emitting diode of the present invention Structure diagram (3) ff diagram is the basic structure diagram of the bare-crystal light-emitting diode of the present invention (four) picture is the structure of the bare-crystal light-emitting diode of the present invention and the circuit board connection diagram Structure of light-emitting diode and screen-printed fluorescent layer. Figure 8 is the structure of a bare-crystal light-emitting diode with a transparent cover according to the present invention. Figure No. 1, LED die 2, packaging resin 3, circuit board 4 Wafer substrate (alumina single crystal) 5. Epitaxial light emitting layer 6. Insulating layer 7. Negative electrode (N pole) 8. Positive electrode (P pole)

Page 12 595015 Abstract of Chinese Invention (Invention Name: Bare Crystal Light Emitting Diode) A variety of bare crystal hairs can be used on the surface. The single crystal (commonly known as flip-chip technology) is used to protect several layers or nanometer dots. The light-emitting diode is directly oxidized with the fine line and fine particles, which is a bare crystal light-emitting and heat-dissipating light diode (Si02 small lens), which is a light-emitting diode (LED), V. The white-and-white adhesive (SMD) structure 'no longer needs to be packaged with a GaN-based (blue light) LED chip substrate which is a transparent sapphire single crystal) as the best natural package. The electrode surface is made into a light reflecting surface and plated at the same time. One layer, and electrode bumps are made, and micro pillars are made on the surface of the substrate to enhance the output of light, that is, the body is completed, and there is no need to perform a packaging process, and the circuit board can be connected directly. Its feature is that it is easy to save and can be used as a high-power light-emitting element. Good car-

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595015 Schematic

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0 --——--Meal; Cantonese,; -._ —]. &Quot;: Case No. 92101158_Year Month and Amendment __ i. Description of the Invention (3) III. Summary of the Invention The present invention creates a bare-crystal light-emitting diode 2 The polar body is directly formed from the LED die to form an SMD component, which can be used without packaging. This creation is to combine high-power die (ρ 〇werchip) with flip-chip contacts (F 1 ipchip), using G a N series LED substrate uses transparent alumina single crystal (Sapphire) substrate as the transparent packaging substrate for light emission, and a light reflection electrode is made on the other side of the LED die, so that all the light energy is reflected to the oxidized single crystal substrate The surface emits light, and at the same time, a 3 丨 02 refractive layer and a micro lens are made to increase the light output brightness or nano-points and nano-pillars, that is, the flip-chip LED die becomes an SMD LED element, without further packaging process ( Traditional flip-chip LEDs need to be repackaged into SMD components, that is, bare-chip SMI LED types can be directly combined with other circuit boards. In this case, since the light-emitting diode substrate must be made of a light-transmitting substrate, the electrodes must be made on the same side. At present, the electrode is on the same side. The only manufacturing method is the gallium nitride (GaN) series blue made from an alumina single crystal substrate. Green light LED elements, and Sic single crystal substrates, because the substrate itself is a conductor, so blue LEDs with SiC as substrates usually have positive and negative electrodes on different sides, and red LEDs have different positive and negative electrodes. Private 4 L U Therefore, the inventions in this case must be designed so that their electrodes are on the same side so that JH Jr can be applied. This is one of the biggest features of the invention. The output of LED light is only 弁 太 台 anti-base ". 九 在 臣 时 界 角 (CriticalAngle) 0 State ^ ^ ^ ^ Seven ~ sin η2 / ηι (ηι is the refraction of the substrate material (Q,. Is generally 1) in this case Sapphire is used as the substrate, and the inner diameter is also ι., = · ... 71 n. Its refractive index is 丨 · 8, so the critical angle of light output is 0 sin γγγλ_〇〇- u. Bbb-, dd. 75, So if the LED is not sealed

Page 7 595015 92101158 _3. Said modified 1: 1 両 丽 7ί package, the bare crystal luminescence will be because the refractive index of the LED light-emitting substrate (1.8) and the refractive index of the air (1) have a large gap, will Some light cannot be emitted due to the large critical angle, and the brightness will decrease. If the LED die is packaged, it will have more light output. Because the refractive index of the packaging resin (EPOXY) is 1.5, the critical angle of light is 0 = sin-11 · 5/1 · 8 = 5 6.44 °. "Bare-type light-emitting diode" is not packaged. If it is used directly, part of the light cannot be emitted because of the refractive index. In order to solve the above disadvantages, the inventor has proposed the following solution to increase the brightness of the bare-LED. : 1. Make a lot of tiny lenses on the light-emitting surface of the sapphire substrate in this case to change the refraction of light output. At the same time, it has a lens focusing function to emit light to the front. The manufacturing method of tiny lenses can use photoresist. After exposure and development, The heating causes the photoresist to form a semi-circular micro lens structure, which can increase the light output. The size of the micro lens can be set to less than 100um, and the most ideal is about 10um. 2. Plating or coating a layer of lower refractive index material directly on the light-emitting surface of the sapphire substrate, the refractive index is between 1.0 and 1.8, such as Si024 transparent organic materials EPOXY, PMMA, PP, etc., and its refractive index About 1.5, the LED bare light output can also be increased. 3. Directly process the sapphire substrate to form tiny bumps on its surface to change the refractive index of light output. If the size of the tiny bumps is smaller than the wavelength of light, most of the light output will not be refracted. Increase the brightness of LED; for example, the blue light wavelength of LED is about 46 Onm. If the bumps on the light-emitting surface of the substrate are less than 40 Onm,

Claims (1)

595.015 \ q; 〇.々 一: '.,:, No. ^ Years and months ^ ^ Five' invention said. (5 "I ----- Bei J LED redundancy will increase a lot, this This kind of structure with bumps on the surface smaller than the wave, this case is called "sub-wavelength nano structure". The sapphire x stone substrate is a very hard material, no matter whether it is chemical or physical, ^, so the inventor of this case wanted One method is to first plate a transparent glass layer (.02 or 8 ^) on the light-emitting surface of the sapphire substrate, and then process the glass-breaking layer (Si〇2 or Si), such as using 6 4 * Surname engraving (wet, engraved) or plasma engraving (dry money engraving) can be successfully completed. 4. Another = a method of generating microstructures is to grow ZnO or Si024, a light-transmitting material, on the light-emitting surface of a sapphire substrate The nano-point or nano-column of nano-Si3N4 can greatly increase the light output of bare LED. The method of growing nano-column can use VLS (gas phase-liquid phase-solid phase method). Taiwan Patent Application No. 0 9 1 1 0 4 6 4 9 filed by the inventor. Fourth, the implementation mode is "bare crystal light emitting diode" in this case. Structure and characteristics, and with the exception give examples please refer to the drawings as follows: Please refer to the first picture for the structure of the traditional surface-adhesive light emitting diode stomach (SMD LED). The first (circuit board type) is to first fix the LED die 1 on the circuit board 3 electrode, and A wire is connected to another electrode, and then the molding resin (2) is molded into a SMD LED shape by molding (m0: Ulng). The second picture shows a bare crystal light-emitting diode of the present invention on the reflective electrode surface 8 of the crystal grains. An insulator layer 6 is required. Generally, a Si 02 film layer or a Sl3N4 film layer is used and is placed on the sapphire substrate 4. The surface is coated with Si 02 or Page 9 595015 Case No. Θ2101158_Year Month and Day V. Description of the invention (7) In the present invention, because the bare-type LED is not packaged, its light is emitted in all directions, and it cannot be focused on a certain point. It can effectively focus and emit the light it emits. It can be exported in advance ^ plastic ^. It will emit a transparent cover with a lens function. Directly cover the transparent cover 丨 7 on the bare LE D1 4 to make it focus. The function is shown in Figure 8. The invention of this case abandons the traditional concept, and the LED die needs to be packaged before it can be used. Because the invention does not require packaging, the manufacturing process is shortened, the yield is improved, and the cost is relatively low. Especially the metal bump contacts are used for better heat dissipation. The present invention is characterized in that a plurality of micro lenses, nano-dots, nano-grains, nano-pillars are fabricated on the surface of the LED die substrate, or a layer of low-refractive material is plated on the surface to increase the light output of the bare crystal. Using the "bare crystal A light-emitting diode" of the present invention, as long as a layer of phosphor powder is printed on the surface (light-emitting surface) of the screen, a white light LED can be turned on, and the light color is more uniform than that of traditional white light. LEDs use glue to distribute their phosphors unevenly). In addition, in this case, if a lens (e.g., pp, PMMA) is added to the surface of the LED, the light can be more concentrated and can be applied to various occasions. Therefore, this case has practical and commercial value, and it is technically creative. More forward-looking and reformative creation. In summary, the technical means of the invention in this case breaks through the traditional concept that LEDs can only be used after being sealed. Bare-crystal LEDs can also be used without packaging. The advantages are volume, long life, good quality, and cost savings, and are suitable for precision devices such as mobile phone keys. on. 595015: 9a 3, No. 92101158 W7tJ Schematic Illustrations 9. Low-refractive layer materials 1 1. Concave and convex microstructures 1. 2. Micro lenses 1. 3. Nano-points or nano-pillars 14. Bare-crystal LEDs 1. 5. Circuit board electrode contacts 16, fluorescent colloid 1 7, transparent cover said correction Page 13