TW444415B - Light emitting diode die and the manufacturing method thereof - Google Patents

Abstract

The present invention relates to a light emitting diode die and the manufacturing method thereof, especially to a manufacturing method with enhanced light-emitting efficiency of the light emitting diode of a compound semiconductor process for growing light emitting diode on an opaque substrate. According to the technology of the present invention, a plurality of concave grooves are formed on the epitaxial film in a dicing way or platform etching way after the electrodes on the front side and back side of the epitaxial film are manufactured, and part of the area of the substrate under the epitaxial film is removed in accordance with a wet or dry etching process to form a mushroom-like structure. By using this mushroom-like structure, when the light emitting diode is lighted, photons can be emitted from the region where the substrate is removed under the epitaxial layer without being absorbed by the substrate. Therefore the luminescent efficiency can be increased.

Description

444415 V. Description of the invention (i) [Scope of the invention] The present invention relates to a light-emitting diode crystal grain and a method for manufacturing the same, and particularly relates to a method for growing a light-emitting diode compound semiconductor material on an opaque substrate. The manufacturing process provides a manufacturing method capable of improving luminous efficiency of a light emitting diode. [Background of the invention] The technology of using a light emitting diode (LED) as a display or a light source generator is known. The structure of a traditional LED die is shown in "Figure 1", which includes: Substrate 1 0 is an opaque medium such as gallium (GaAs); an epitaxial layer 2 0 is grown on the substrate 10, which is a light-emitting diode compound semiconductor material; The front electrode 30 and a back electrode 40. • Limitations on the substrate 10 of some compound semiconductor materials during the manufacture of traditional LEDs, so that when the LED die emits light, photons are absorbed by the substrate 10 and do not transmit light (as shown in "Figure 2"). Due to the structural characteristics of the material, when the LED die is emitting light, the efficiency of photon emission is greatly reduced, and the defect that the luminous efficiency cannot be effectively displayed is an unavoidable obstacle in the manufacturing process of the traditional LED die. [Objective and Summary of the Invention] Therefore, the object of the present invention is to provide a structure different from the conventional LED die, which uses an etching process to remove a part of the substrate area from below the epitaxial layer to obtain a mushroom-like structure. LED die with a structure like structure, so that when the LED die is lit, photons can be emitted from the area where the substrate is removed under the epitaxial layer,

4 444 1 5 V. Description of the invention (2) To improve the luminous efficiency of the LED die. According to the above-mentioned object of the present invention, a method for manufacturing a light-emitting diode crystal grain includes at least the following steps: (1) providing a substrate, wherein the substrate is made of an opaque material (such as GaAs) (2) growing an epitaxial layer with a light-emitting diode structure on the substrate to form a worm wafer * wherein the worm-crystal layer is a light-emitting diode compound semiconductor material; (3) a metal ( For example, a P-type gold-beryllium alloy, or an N-type gold-germanium alloy) is plated on the front surface of the epitaxial wafer, and then annealed to generate a front electrode; (4) a metal (such as a P-type gold-beryllium alloy, or N-type gold-germanium alloy) is recorded on the back of the worm wafer, and then annealed to generate the back electrode; (5) Etching on the epitaxial wafer by cutting or platform etching (such as dry etching or wet etching). A plurality of grooves; (6) etching the substrate in the groove by wet or dry etching, and removing a part of the area of the substrate from below the epitaxial layer; and (7) cutting the Insect wafers to form light-emitting diode grains. Among them, the true technical core of the present invention is in steps (5) to (7). As for the purpose of steps (1) to (4), only an epitaxial wafer with front and back electrodes is prepared for subsequent processes. Some detailed processes are still included between steps (1) to (4). At the same time, these detailed processes can be changed with the process equipment and process planning. For example, in the process of forming the front and back electrodes on the epitaxial wafer, it may be Need to be coated

Page 5 4444 1 5 V. Description of the invention (3) Related processes such as marginal layer and conductive layer; or some processes between steps (1) to (4) can be omitted, such as steps (3) and (4) ) Annealing steps can be combined, that is, the metal is plated on the front and back of the epitaxial wafer to form the front and back electrodes, and then the annealing process is performed at the same time, but no matter which process, as long as a The worm wafer of the electrode can be subjected to subsequent etching steps. Therefore, in the present invention, the steps in between are not described in detail, and only the related technologies in steps (5) to (7) are discussed. In order to make the above and other purposes, features, and advantages of this creation more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings for detailed description as follows: [Schematic description of the drawings] Figure 1, It is a schematic diagram of the structure of a traditional LED die. Fig. 2 is a schematic diagram showing the light emission of the L E D crystal grains in "Fig. 1". Figures 3a to 3e are flowcharts of the manufacturing process of the mushroom-shaped LED particles of the present invention. Fig. 4 is a schematic diagram showing the structure of the mushroom-shaped LED crystal grains of the present invention. Fig. 5 shows the luminescence of the mushroom-shaped LED crystal grains shown in "Fig. 4". [Embodiment description] Please refer to "3a-3e", which is a flowchart of manufacturing the mushroom-shaped LED die of the present invention, in which Fig. 3a shows the structure of the epitaxial wafer which has completed the fabrication of the front and back electrodes. :

4444 1 5 V. Description of the Invention (4) A substrate 10 is made of opaque medium such as gallium arsenide (GaAs); an epitaxial layer 20 is grown on the substrate 10, to form an epitaxial wafer, in which the epitaxial layer 20 is a light emitting diode compound semiconductor material, such as aluminum gallium arsenide single heterostructure or double heterostructure (AlGaAs SH or DH Structure) and quaternary indium gallium Scale (InGaAlP) material; a front electrode 30, which is formed by bonding a metal (such as a P-type gold-beryllium alloy, or an N-type gold-germanium alloy) to a remote chip using a money bond (or vapor deposition) method. Front side 'and annealed front electrode 3 0 to form an ohmic contact (Ohmic Contact); and a back electrode 40, formed by sputtering (or steaming bell) the metal (such as a P-type gold-beryllium alloy) , Or N-type gold-germanium alloy) is plated on the back surface of the epitaxial wafer and annealed to form a back electrode 40 of the Ohmic Contact. The process disclosed in the present invention is to remove a part of the substrate from below the epitaxial layer 20 by an etching process after the front and back electrodes have completed ohmic contact between the metal and the semiconductor (as shown in FIG. 3a). An area of 10, so that the lower part of the worm crystal layer 20 is not completely in contact with the substrate 10, and when the led crystal grains are lit, photons can be emitted from the area where the substrate 10 is removed from under the telecrystal layer 20, Instead of being absorbed by the substrate 10, the luminous efficiency can be improved. In the present invention, in order to ensure that the area of a part of the substrate 10 can be removed from below the stupid crystal layer 20 after this inscription process, the above-mentioned silver inscription process is specifically divided into two steps. The first step is First use cutting method or flat

Page 7 444415 V. Description of the invention (5) The MESA etching method enables the wafer to form a plurality of grooves 2 2 (as shown in "Fig. 3-b"), followed by wet etching (W et Etching) or Dry Etching, the substrate 10 is etched in the groove 22, and the area of a part of the substrate 10 is removed from below the epitaxial layer 20. The appearance shape of the plurality of grooves 2 2 formed in the first etching step is not limited, and may be a V-shape, an inverted gate type, or a round shape. In the embodiment disclosed in the present invention, the groove 2 2 The appearance is a V-shaped semi-penetrating form as shown in "Figure 3-b". There are many implementations of the cutting and platform etching methods used in this step. For example, a cutting knife can be used for cutting. The platform etching method includes wet etching and dry etching. The former mainly uses chemical reactions to etch the epitaxial wafers, and the latter mainly uses physical effects to perform the epitaxial wafer etching (but not Completely) 'such as Plasma Etching, / Sputtering Etching, or Reactive Ion Etching (active Ion Etching, RIE), etc., no matter which kind of etching method', as long as it can achieve the epitaxial wafer The purpose of forming the plurality of grooves 22 can be implemented in the present invention. The definition of the V-type semi-penetrating form disclosed in this embodiment is: the longitudinal etching depth (Η) is greater than the thickness (h) of the epitaxial layer 20, as for how much H must be greater, there is no limitation in the present invention. According to the user's design, = Μ In this step, if the longitudinal etching depth (H) is greater than the thickness (h) of the epitaxial layer ^ 2, the more it can ensure that after the next etching step, the substrate 10 and Cross-section of substrate 10 between interfaces where epitaxial layer 20 contacts

4 4 4 4 1 9 V. Description of the invention (6) The product will be smaller than the wear area 5 of the epitaxial layer 20 and reach the J of the present invention @. Therefore, y can also be used to make the vertical money engraving depth in the first step. (H) is equal to or less than the thickness (h) of the epitaxial layer 20 (as shown in "Fig. 3-e J"), and a larger portion of the crystal layer 20 J is etched when the next step is performed. The same purpose can be achieved. No matter whether the step * is formed as shown in Fig. 3-bj or Fig. 3-6-, the second etching step is followed by the second etching step disclosed in the present invention. Wet or dry engraving removes the area of a part of the substrate 10 from under the crystal layer 20 and in the embodiment disclosed in the present invention, it uses— »Wet Engraving> to remove part of the substrate 1 0 The area y is so that the present invention selects a 4k etch solution 5 to make the silver The etching rate of the epitaxial layer 20 by the etching solution (defined as R1) is lower than the 4k etching rate of the substrate 10 (defined as R2) or the area of the substrate 1 0 is selectively etched to cause the crystal layer during the etching process. 2 0 The area to be engraved will be smaller than the area to be engraved on the substrate. 10> A wafer with a fragrant structure as shown in the factory's Fig. 3-cj is formed. The user can change the type or composition ratio of the etching solution to Control the size of the etching rate (R1 R2) of the crystal layer 2 0 and the substrate 1 0 at this moment, and control the area etched by the epitaxial layer 2 0 and the substrate 1 0 by M. Where the value of R1 is smaller than the value of R2, it represents The more selective the etching solution is, that is, the stronger the reactivity between the etching solution and the substrate 10 is, the more the area of the substrate 10 is engraved by the surname. When the R1 value is much smaller than the value of 1? 2, the etching solution Reactivity to substrate 1 0 is too strong, so only the substrate 1 0 There is no limit to the size of the 10 area of the 4k engraved base plate.

444415 Jade, description of the invention (7) As long as the purpose of the present invention can be achieved, only when the area of the substrate 10 is etched more, the ratio of photons absorbed by the substrate 10 will be lower, and the The higher the luminous efficiency, but this does not mean that the area of the substrate 10 can be etched indefinitely. The structure of the entire LED die still needs to be considered. Therefore, the user can select the material of the substrate 1 Q, epitaxial layer 20, R1, and Factors such as R2 and so on, select the type of etching solution in a timely manner to achieve the maximum luminous efficiency. The etching solution used in this embodiment is a mixed solution composed of ammonia (NH40H) and hydrogen peroxide (Η 2 0 2). The user can adjust the ratio of the etching solution by adjusting the mixing ratio of ammonia and hydrogen peroxide. The engraving rate of the epitaxial layer 20 and the substrate 10, and in the preferred embodiment disclosed in the present invention is a mixed solution of ammonia water and hydrogen peroxide at the same ratio at room temperature (that is, NΗ40Η: Η 2 0 2 = = 1: 1) The effect of the etching is the best. The worm-shaped structure of the insect wafer after the etching is as shown in FIG. 3-c. After obtaining the structure as shown in "Figure 3-c", this worm-shaped wafer with a zirconium structure is cut into one and one grains by a cutting knife, as shown in "Figure 3-d". Up to this step, the fabrication of the LED die with a mushroom-shaped structure of the present invention is completed. In order to more clearly explain the difference between the LED chip of the mushroom-shaped structure of the present invention and the traditional LED chip, an LED chip in "Figure 3-d" is enlarged to explain it, as shown in "Figure 4" Show. Comparing "Fig. 1" with "Fig. 4", it can be clearly seen that in the "Fig. 4", the epitaxial layer 20 is not completely in contact with the substrate 10, that is, the remote crystal layer 2 〇Part of the area below is bare to the outside environment, so when L e D is lit

Page 10 4444 1 5 V. Description of the invention (8), the photons can be emitted from the bare space under the crystal layer 20 (as shown in Figure 5 of the factory) to reduce the absorption rate of photons by the substrate 10 can be increased The luminous efficiency of LEDs. Although the present invention is disclosed in a preferred embodiment, it is not intended to limit the scope. 5 Anyone skilled in this art can make some changes and decorations without departing from the spirit and scope of this creation. For example, The appearance of the LED die of the present invention is not limited to the shape of shiitake mushrooms, but can also be changed to other geometric shapes. 3 This can be achieved through the planning of the selective engraving process of the melting and engraving solution, and its implementation is not difficult. The process of forming a wafer with front and back electrodes can also be changed for iBb because the focus of the present invention is on the subsequent silver engraving process and therefore the The process can be replaced by y * will not affect the subsequent engraving process, so as long as the cost of the invention can be removed by the engraving process from the '-' epitaxial layer part of the substrate area so that photons can be removed from the substrate under the worm crystal layer The purpose of improving the luminous efficiency of the LED die by shooting out the area can be implemented in the present invention regardless of any technical means. Therefore, the scope of protection of this creation shall be subject to the definition in the patent scope as attached. 0 [ Efficacy of the invention] Since the present invention removes a part of the substrate area J from a worm crystal layer through a 4k engraving process, when the LED die is lit, its photons can be emitted from the area removed by the substrate under the epitaxial layer. Decreasing the ratio of photons absorbed by the substrate can improve the luminous efficiency of the LED die. 3 [Explanation of Symbols 1 0 Substrate

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Claims (1)

444415 Case No. 88101545 Amendment 6. The scope of the patent application is a substrate of light-emitting diode crystals, which consists of a remote crystal layer and a surname engraving process. The wafer's area is used to expose the bare space to the outer particles, including: Made of light material; longer than the surface of the substrate to form an epitaxial layer removed from below the epitaxial layer, a portion of the area below the substrate is not in contact with the substrate to improve the luminescence of the light emitting diode grains Efficiency; 2 4 front electrode, back electrode, cutting process package) to cut several grooves (2) to wet-type the surface of the substrate in the no slot for the base, such as the crystal layer of the patent scope Of the etching process. For example, if the vertical etching depth of the engraving process of the second layer of the patent application range is greater than that of the application of the second layer of the etch process of the patent application range, such as # (1, a complex aa is formed on the front surface of the distant worm wafer. On the back of the insect wafer. The light-emitting diode die according to item 1, the method includes the following steps: a method or a platform etching method on the semiconductor chip; and a dry etching method or a dry etching method to etch on the board, and The product is transferred from below the epitaxial layer. The light-emitting diode grains described in item 2, the plurality of grooves in the epitaxial step (i) are V-half light-emitting diode grains described in item 3. The plurality of grooves in the insect step (1) are V-shaped and the thickness of the crystal layer. For the light-emitting diode grains described in item 2, the wet-type money engraving in the step (2) is selected. as well as P.13 4444 1 5 _Case No. 88101545_Year Month and Date ___ 6. Apply for a patent for etching solution, so that the etching efficiency of the etching solution to the epitaxial layer is less than the silver etching efficiency of the substrate or selective The substrate is engraved, and a part of the area of the substrate is removed from below the worm crystal layer. 6. According to the light-emitting diode grains described in item 5 of the scope of the patent application, the etching solution selected in the wet etching of step (2) of the epitaxial layer etching process is a mixed solution composed of ammonia and hydrogen peroxide. . 7. According to the light-emitting diode grains described in item 6 of the scope of the patent application, the etching solution selected in the wet etching of step (2) of the epitaxial layer etching process is a mixture of ammonia and hydrogen peroxide at room temperature. The preferred ratio is 1 ·· 108. The light-emitting diode grains are described in item 1 of the patent claim, and the material of the substrate is a shattered gallium compound. 9. According to the light-emitting diode grains described in item 1 of the scope of the patent application, the material of the epitaxial layer is selected from the group consisting of a single heterostructure, a double heterostructure, and a quaternary aluminum indium gallium filler. . 10. According to the light-emitting diode grains described in item 1 of the scope of the patent application, the material of the front electrode is selected from one of a P-type gold-beryllium alloy and an N-type gold-tallium alloy. 1 1. According to the light-emitting diode grains described in item 1 of the scope of the patent application, the material of the back electrode may be selected from one of a P-type gold-bond alloy and an N-type gold-alloy. 12. A method for manufacturing light-emitting diode crystal grains, comprising at least the following steps: (1) providing a substrate, wherein the substrate is an opaque material Page 4 of 4444 1 5 _Case No. 88101545_Year Month and Date__ VI. The patent application scope is made of quality; (2) On the substrate, a worm crystal layer with a light-emitting diode structure is grown to form · A remote wafer, (3) detecting the metal on the front surface of the worm wafer and then annealing to generate a front electrode, (4) plating the metal on the back surface of the epitaxial wafer, and then annealing to generate a back electrode; Cutting or platform etching to form a plurality of grooves on the epitaxial wafer; ('6) The substrate is etched in the groove by wet or dry etching and removed from under the epitaxial layer Part of the area of the substrate; and (e) cutting the epitaxial wafer to form light emitting diode crystals. 13. The method for manufacturing a light emitting diode crystal according to item 12 of the scope of patent application, wherein the material of the substrate may be a gallium arsenide compound. 14. The method for manufacturing a light-emitting diode crystal according to item 12 of the scope of the patent application, wherein the material of the stupid crystal layer may be a single heterostructure or a double heterostructure or a quaternary aluminum indium gallium. phosphorus. 15. The method for manufacturing a light-emitting diode crystal according to item 12 of the scope of patent application, wherein the material of the front electrode may be a P-type gold-bond alloy, an N-type gold-alloy, and the back electrode The material can be P-type gold-alloy alloy and N-type gold-alloy alloy. 16. A method for manufacturing a light-emitting diode die, which is attached to a stupid wafer that has been manufactured with front and back electrodes. P.15 4444 1 5 Page 16 Case No. 88101545 ^ _ Revision 6. The area of the substrate removed under the crystal layer on the wafer for patent application > The steps of the tapeworm engraving process include (1) cutting or platform contact A plurality of grooves are formed on the wafer by etching, and (2) a wet or dry 1 insect engraving method is used to etch the substrate in the groove J, and a portion of the substrate is removed from below the crystal layer Area Ό 1 7 The manufacturing method of the light-emitting diode crystal grains as described in item 16 of the patent scope, wherein the wet 1 insect engraving method in step (2) is to select a guest insect engraving solution to make the 1 insect The engraving efficiency of the engraving liquid on the crystal layer is less than the engraving efficiency of the substrate or 5 疋. Selectively engraving the substrate and removing a part of the substrate below the crystalline layer The area is 0 1 8 As described in the patent chapter, the method for manufacturing light-emitting diode crystals described in item 17 is described, wherein the tapeworm engraving solution can be ammonia water. A mixed solution composed of hydrogen peroxide and 〇1 9 N As described in item 18 of the patent application, the method of making light-emitting diode crystals is described in Method 1. The preferred ratio of mixing ammonia water with hydrogen peroxide is 20%. The luminescence described in item 6__ The manufacturing method of polar crystal grains, wherein the appearance shape of the plurality of grooves may be a V-shaped half form. The method of manufacturing polar body grains is defined as a semi-penetrating form in which the longitudinal depth is greater than the thickness of the epitaxial layer.