TWI225315B - Method for forming LED - Google Patents

Abstract

The present invention relates to a method for forming LED. In the present invention, LED dies are defined by photolithographic and etching processes to replace a cutting step, and a metal substrate of the LED is formed by chemical or physical methods.

Description

1225315 V. Description of the invention (1) The technical field to which the invention belongs ... The present invention relates to a method for forming a light emitting diode, in particular to a method for forming a metal substrate of a light emitting diode by chemical or physical methods . Prior technology: Basically, the light-emitting diode (Light Emitting Diode 'LED) uses the inherent characteristics of semiconductors, which is different from the discharge and heat-emitting principle of conventional incandescent lamps. Therefore, light-emitting diodes are called cold Light source (c ο 1 d 1 ight). Compared with traditional incandescent or mercury lamps, light-emitting diodes have the advantages of high durability, long life, light weight, low power consumption, and no harmful substances such as mercury. The basic element structure of a light-emitting element is a P N diode structure, which includes a P-epitaxial layer and an N-epitaxial layer, with an active light-emitting layer sandwiched therebetween. Generally speaking, the current input of the light emitting diode is through two electrodes on the epitaxial. Due to the choice of materials for the epitaxial layer and the growth substrate, the electrodes on the light-emitting diode epitaxial layer can be located in the opposite direction or the same direction of the epitaxial layer, as shown in Figures A and B. Taking gallium nitride (G a N) -based light-emitting diodes as examples, the long-crystal substrates commonly used include non-conductive sapphire substrates (Sapphire, A1203) and conductive silicon carbide (SiC). After the epitaxial structure is completed, the shape of the gallium nitride light-emitting diode using Sapphire as the growth substrate 40 is shown in FIG. 1A, in which an N-type epitaxy is sequentially arranged on the substrate 40

Page 6 1225315 V. Description of the invention (2)-Layer 30, active light-emitting layer 20 and P-type epitaxial layer 10, and part of the exposed region of N-type epitaxial layer 30 and p-type epitaxial layer 10 are respectively The bonding electrodes (P ad) 2 5 and 15 were formed. The shape of the gallium nitride light-emitting diode using silicon carbide as the growth substrate is shown in FIG. 1B, and an N-type stupid crystal layer 30, an active light-emitting layer 20, and The P-type epitaxial layer 10 and the bonding electrodes 15 and 25 are formed on the upper surface of the P-type epitaxial layer 10 and the lower surface of the silicon carbide substrate 50, respectively. Because the bonding electrodes (Pad) 25 and 15 have the problem of covering or absorbing the light emitted from the crystal grains, in order to increase the brightness of the light emitting diode, some manufacturers switch to F 1 ip C hip Process technology. As shown in FIG. 1C, the structure of the light-emitting diode is opposite to that of the first A, and there are a P-type epitaxial layer 10, an active light-emitting layer 20, and an N-type epitaxial layer 30 in order from bottom to top, and a substrate is above 40, the light is mainly emitted upward from the 40 side of the substrate. The substrate 40 is a transparent substrate, so it does not encounter the problem of covering or absorbing. Generally, it will stick to another Submount 60, and a reflective layer can be made at the same time, so that the light emitted downward can also be reflected upward. And because the carrier can choose a material with better heat dissipation, such as metal, it can dissipate the heat generated by the light emitting diode, which is more conducive to operation under large current. Therefore, the LED can increase its luminous brightness after cladding, and its heat dissipation is better. Although the use of flip-chip technology has greatly improved the luminous brightness of the light-emitting diode, it is suitable for high-current operation. However, the current conventional flip-chip technology requires the use of bonding technology to connect the bonding electrode of the light-emitting diode and the carrier, and the yield of the bonding has not been low, which has caused the production of the light-emitting diode of the flip-chip. Yield has also been unable to effectively improve 'and cost improvement

Page 7 1225315 V. Description of Invention (3) South. Summary of the Invention: In view of the above, the brightness of the present invention is based on the body of the polar body of the present invention. The brightness of the polar body of the present invention is based on the cube of the body. In the background of the chemistry or the invention, there are many problems and disadvantages caused by the light emitting diode technology provided by the traditional method. The main purpose of the present invention is to provide a method for forming a light emitting diode to improve the light emitting diode rate. Another purpose is to form a light-emitting bimetal substrate by chemical or physical means to increase its electrical conductivity and heat dissipation. Another object is to form a reflective layer to increase the light emitting diode method. The layer is also lifted on the polar layer and the surface of the crystal layer. Physically, the purpose of forming the above-mentioned engraved crystal grains is to provide electricity. The present invention provides a method for forming a light emitting diode including the following steps. A light-emitting diode on a temporary substrate; lithographically etch the light-emitting diode into light-emitting diode grains; form a reflective layer thereon; chemically or physically form a metal layer as a permanent substrate; After the temporary base is removed, the light-emitting diode die is removed and the substrate is barely provided with a method for forming a light-emitting diode. The above method steps: forming a light-emitting diode epitaxial layer on a temporary formation of a reflective layer on the light-emitting diode grains; forming a metal layer on the reflective layer by a method; lithography

Page 8 1225315 V. Description of the invention (4) Etching removes the temporary and removes the temporary. Therefore, using the physical conductivity of this physical method requires only a good single-phase conductivity in time. It is suitable for the above-mentioned methods such as chemical CVD, Cut. Furthermore, the brightness of the light emitting diode. Die, moving the die to chemically or increase the substrate direction, the package substrate heat sinks the diode. PVD or PVD can be used to effectively etch the body's luminescent photodiode epitaxial layer into a luminescent diode substrate; and forming electrodes on the exposed surface of the luminescent diode substrate. Inventing the above method for forming a light emitting diode, forming a metal layer, as a permanent substrate, not only dissipates heat, but also can make electrodes on opposite wires, which can improve the yield of wire bonding, and because the metal operates at high current, it can produce high Power luminescence or physical methods include electroplating and electroless plating. These methods can control the thickness of the metal substrate: the cutting process can also reduce the light-emitting diode system to form a reflective layer on the light-emitting diode grains, and the light is guided in a single direction to enhance Light emitting diode implementation method: Some embodiments of the present invention will be described in detail as follows. However, with the exception of the embodiments described in detail, the present invention can also be widely implemented in other embodiments, and the scope of the present invention is not limited, which is subject to the scope of the subsequent patent applications. Furthermore, in order to provide a clearer description and easier understanding of the present invention, the parts in the diagram have not been drawn according to their relative dimensions, and some dimensions have been exaggerated compared to other related dimensions; irrelevant details have not been completely drawn.

Page 9 1225315 V. Description of the Invention (5) Draw out for simplicity of illustration. The main inventive spirit of the present invention is to recognize a metal layer as a permanent substrate in a manner of forming an inscription or a carbonized carbide substrate as a permanent substrate. For example, 3 f, the bipolar body is oxidized and dissipated, and the electrode can be made on the opposite side = plus = conductivity and wire, which can improve the yield of wire bonding, and Operation #, can produce high power "^ Applicable physical methods include the key, no electricity ·: PVD- and cj with 2 :? complexity of the light-emitting diode system. Furthermore, this is due to the metal layer and light-emitting diode crystal A two-emission layer is formed between the grains (or remote crystal layers), which can effectively guide the light emitted by the diode grains to the same direction, and increase the luminous brightness of the light-emitting diode. According to the spirit of the present invention, The present invention discloses several preferred embodiments to illustrate a method for forming a light-emitting diode having the advantages described above. The second and second drawings A to D are a process step of a preferred embodiment of the present invention. In the second diagram A, first, a light-emitting monopolar layer 105 is formed on a temporary substrate 丨 00, and a light-emitting worm is used to form a light-emitting monopolar layer on the crystalline layer 105. For the crystal grain 1 10, as shown in FIG. 2B, the preferred etching method for the light-emitting diode worm crystal layer 105 is dry etching. Then, a reflective layer 120 and a metal layer 130 are sequentially formed on the light-emitting diode crystal grains 110. The metal layer 130 is formed in an electrical manner. The metal layer 130 is connected between the crystal grains and the crystal grains. The thickness is about 5 ~ 3 0 // m to facilitate subsequent splitting of the metal layer 13 0, as shown in the second C diagram.

Page 10 1225315 V. Description of the invention (6) 'Next, the temporary substrate 100 is removed, and then formed on the exposed surface of each light-emitting diode die 1 110 after the temporary substrate 100 is removed. The electrode 1 40, as shown in the second D diagram, cleaves the metal substrate to form independent light-emitting diode grains. A process step of another preferred embodiment of the present invention is shown in FIGS. 3A to 3D. In FIG. 3A, first, a light emitting diode epitaxial layer 105, a reflective layer 12 and a metal layer 1 3 0 are sequentially formed on the temporary substrate 100, in which the metal layer 1 3 0 It is formed by electroplating, as shown in the third A diagram. Then, independent light-emitting diode crystals 1 1 0 are formed by lithographic etching, as shown in FIG. 3B. Next, the formed light-emitting diode is adhered to the blue film 150, and then the temporary substrate 100 is removed, as shown in the third figure C. Finally, an electrode 140 is formed on the exposed surface of each of the light-emitting diode grains 110 after the substrate 100 is removed, as shown in the third D diagram. In the present invention, the reflective layer can reflect the light of the light emitting diode to increase the external brightness of the light emitting diode. The preferred material of the reflective layer is silver, aluminum, rhodium, platinum, palladium, nickel, titanium, cobalt, gold Wait. However, if the light-emitting diode is a blue light-emitting diode (such as a gallium nitride light-emitting diode), and gold absorbs light in the blue band, it is not recommended to use gold as the material of the reflective layer. In addition, the preferred material of the metal layer is copper or other metal with good heat dissipation effect, which helps the heat dissipation of the light emitting diode, and improves the stability and service life of the light emitting diode. The preferred thickness of the metal layer is about 30-100 microns. According to the above, the present invention provides a method for forming a light emitting diode.

Page 11 1225315 V. Description of the invention (7) The above method includes the following: etching a light-emitting diode die on a temporary substrate; electroplating a single substrate; and forming a bare surface on the surface of the board. The present invention also provides: The method includes the following steps: A metal electrode plate is plated on the substrate, so that the bare silicon substrate can be wire-bonded, and the grains are oriented upwards and opposite to each other. The mentally stupid crystal layer and the shaped surface use the original metal substrate. The yield of the electrode system can be produced to form an anti-lifting. I learned this and formed a layer with the range on the etching to form the upper layer of the electrode invention. The method is used in the phase and due to the high power emission layer, the photodiode technology is not used. The steps made: forming a light-emitting diode epitaxial layer; lithographically etching the light-emitting diode epitaxial layer; forming a reflective layer on the light-emitting diode metal layer on the reflective layer ; Removing the temporary electrode and removing the substrate from the light emitting diode grains to form a light emitting diode. The above method forms a light-emitting diode epitaxial layer on a temporary reflective layer on the light-emitting diode epitaxial layer; on the reflective layer; lithographically etches the light-emitting diode crystal grains; In addition to the temporary method of forming a light-emitting diode, which is described later after removing the substrate from the light-emitting diode grains, the electroplating method is used as a permanent substrate instead of the traditional aluminum oxide or carbon to increase the conductivity and heat dissipation of the substrate. In this reverse direction, only a single wire is required when packaging, which can improve the heat dissipation of the metal substrate and is suitable for high-current operation of light-emitting diodes. Furthermore, the light-emitting diode crystal can effectively guide the light of the light-emitting diode to the light-emitting brightness of a single body. However, although the present invention is illustrated by a preferred example, the spirit of the present invention is limited. Modifications and similar arrangements that do not depart from the invention should be included below

Page 12 1225315 V. The scope of the patent application mentioned in the invention (8) should be consistent with the broadest interpretation covering all modifications and similar structures. Therefore, a preferred embodiment of the present invention described above can be used to identify various changes made without departing from the spirit and scope of the present invention.

Page 13 12315315 Brief description of the drawings and diagrams: The first diagram A to the first C are schematic diagrams of the structure of light-emitting diodes in the conventional art; the second diagram A to the second diagram D according to the present invention A schematic diagram of a method for forming a light-emitting diode shown in a preferred embodiment; and a schematic diagram of a method for forming a light-emitting diode shown in FIGS. 3A to 3D according to another preferred embodiment of the present invention. . Graphical symbol comparison table: P-type epitaxial layer 1 0 Bonding electrode 1 5 Active light-emitting layer 2 0 Bonding electrode 25 N-type epitaxial layer 3 0 Crystal substrate 4 0 Silicon carbide substrate 5 0 Substrate carrier 6 0 Temporarily Substrate 1 0 0 light emitting diode epitaxial layer 1 0 5 light emitting diode grain 1 1 0 reflective layer 1 2 0 metal layer 1 30 electrode 1 4 0 film 1 5 0

Claims (1)

1225315 6. Scope of patent application Patent scope of application 1. A method for forming a light-emitting diode to form a light-emitting diode epitaxial layer. The light-emitting diode epitaxial grain is temporarily etched by lithography; a reflective layer is formed on The light-emitting diode crystal forms a metal layer permanent metal substrate by chemical or physical methods; removing the temporary substrate; and forming an electrode on the light-emitting diode crystal to move on. Separate the metal substrate with mechanical stress, and use grains. 2. For example, the material of the reflective layer in the formation of item 1 of the patent application scope is one of silver, inscription, key and gold, or a combination thereof. 3. The chemical method as described in the formation of item 1 of the patent application scope includes one of electroplating, electroless electricity, or a combination thereof. 4. The method for forming a light-emitting diode as described in the first patent application scope, wherein the physical method includes physical vapor deposition. 5. If the formation of item 4 of the applied patent scope includes physical vapor deposition including vapor bonding and sputtering, the following steps are included: on the temporal substrate; the layer is etched on top of the light-emitting diode grains; and on the reflection As a method for forming an independent light-emitting diode on the exposed surface of the substrate after removing the substrate, the method of turning, turning, condensing, recording, Qin, and junction light-emitting diodes, its plating, chemical vapor deposition A method of emitting a light emitting diode, which is used for plating one or a combination thereof. Page 15 1225315 6. Scope of Patent Application 6. One of the methods of removing the temporary substrate in the scope of patent application item 1 or a combination thereof. 7. If the metal layer in item 1 of the scope of patent application is one of copper, aluminum, nickel handle, age, iron or 8. If the metal layer thickness in item 1 of the scope of patent application is greater than 30 // m 9. If In the scope of the patent application, the metal layer in each intergranular phase is 10. 10. A kind of light-emitting diode is formed, a light-emitting diode epitaxial layer is formed, a reflective layer is formed in the light-emitting diode by chemical or physical methods to form a permanent A substrate; etching the light-emitting diode layer with a lithography to make the light-emitting diode epitaxially remove the temporary substrate; and forming an electrode on the light-emitting diode. 11. If the scope of patent application is No. 10, where the material of the reflective layer is one or a combination of silver, cobalt and gold 12. If the scope of patent application is No. 10 The method of forming a light-emitting diode is a method of forming a light-emitting diode by grinding, etching, and laser peeling, which is a combination of I, M, Yan, silver, gold, titanium, cobalt. The method for forming a light-emitting diode, the method for forming a light-emitting diode, and the method of connecting the thickness between 5 and 30 // m include the following steps: On a temporary substrate; Above the crystal layer, a metal layer is on the reflective layer, and serves as an epitaxial layer, the reflective layer, and the metal layer are etched to form light emitting diode grains; the exposed surface items of the crystal grains after the substrate is removed form the light emitting diodes. The method of the polar body, the method of forming a light-emitting diode of the following items: Page 16 1225315 6. Scope of patent application, one of the chemical methods or a combination thereof 13. If applying for a patent, the physical method 14. If applying for a patent, the physical gas phase is combined with 0. 15. If applying for a patent, the removal is temporarily One of them or 16. If the patent is applied for, the metal layer is starting, concubine, iron, iron 17. If the patent is applied, the thickness of the metal layer includes electroplating, electroless plating, chemical vapor deposition A method for forming a light emitting diode includes physical vapor deposition. The method of forming a light-emitting diode in the range of item 13 includes one of vapor deposition and sputtering or a method of forming the light-emitting diode in the range of item 10, and the method of polishing a substrate is etching. And laser stripping combinations. The method for forming a light-emitting diode in the range of item 10, copper, Shao, nickel, I, town, silver, gold, titanium, one or a combination thereof. The method of forming a light emitting diode in the range of item 10 is greater than 3 0 // m Page 17