Method for manufacturing light emitting diode capable of adjusting light beam shape of light output surface

Abstract

The present invention proposes a method capable of adjusting the light beam morphology of a light emitting diode, comprising the following steps: making an epitaxial layer on a substrate; processing the epitaxial layer to make an ohmic contact, defining the light beam morphology, and laser etching the corresponding area of ​​the substrate layer with the aid of corresponding alignment marks to obtain a corresponding graphic structure, thereby obtaining a chip having a preset light beam morphology. The present invention can obtain a light emitting diode chip with an adjustable light beam morphology on the light-emitting surface by a simple process, has a low production cost, and can be applied to light emitting diodes with different substrate structures.

Description

Technical Field

[0001] The invention relates to the field of chip manufacturing, and in particular to a method for manufacturing a light emitting diode capable of adjusting the light beam shape of a light emitting surface. Background Art

[0002] Light-emitting diodes, abbreviated as LEDs, are a type of semiconductor diode that can convert electrical energy into light energy. In some lighting applications that require high directivity, the shape of the LED spot needs to be strictly controlled. Currently, common light-emitting morphology control usually uses LED chips with vertical thin-film structures to make the light-emitting area into the shape of the target spot to achieve the target light-emitting morphology, or to make a structure that emits light from a transparent substrate surface, and perform secondary photolithography, metal plating or other opaque materials on the thinned and polished substrate surface to define the target spot. The above two processes have complex production processes and high costs, especially the vertical structure, which requires a substrate bonding process and expensive laser stripping equipment. When the flip-chip back is thinned and the back is lithographically processed and metal or opaque materials are produced, photolithography, coating, metal stripping and other processes need to be performed on the thinned substrate, which is prone to cracking, breakage and other problems that seriously affect the process yield, resulting in complex processes and high costs.

[0003] Traditional LED manufacturing methods usually use standard photolithography and etching techniques to define electrodes and light-emitting areas. Although these methods show high efficiency in mass production, they have limited ability to control the beam shape of the LED light-emitting surface. For applications that require specific light distribution, such as automotive headlights, special lighting, and decorative lighting, traditional technologies are difficult to achieve complex and customized spot effects, which limits the market adaptability and user experience of LED products.

[0004] In addition, the processing of LED substrates in the prior art is mostly focused on improving light transmittance or conductivity, and less attention is paid to optimizing the light spot shape through physical structural modification. For example, some improvement methods may include using substrates of different materials or structures to enhance light extraction efficiency, but this method often ignores the fine control of light distribution on the light-emitting surface. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a method for manufacturing a light emitting diode capable of adjusting the light beam shape of a light emitting surface.

[0006] The main contents of the present invention include:

[0007] A method for manufacturing a light emitting diode capable of adjusting the light beam shape of a light emitting surface comprises the following steps:

[0008] Manufacturing an epitaxial wafer, the epitaxial wafer comprising a substrate layer and an epitaxial layer grown on a first surface of the substrate layer; an alignment mark is provided on a surface of the epitaxial layer away from the substrate layer; the epitaxial layer comprises a light-emitting area and a non-light-emitting area surrounded by the light-emitting area;

[0009] According to the alignment mark, a light emitting area and a non-light emitting area of ​​the second surface of the substrate layer are determined; the second surface of the substrate is a surface opposite to the first surface of the substrate layer;

[0010] According to the type of substrate and the preset beam morphology, laser etching is performed on the corresponding area of ​​the second surface of the substrate layer to obtain a corresponding etching pattern.

[0011] Preferably, according to the type of substrate and the preset beam morphology, laser etching is performed on the corresponding area of ​​the second surface of the substrate layer to obtain a corresponding etching pattern, including:

[0012] When the substrate layer is a transparent or semi-transparent substrate, laser etching is performed on the non-light-emitting area of ​​the second surface of the substrate layer according to a preset beam shape to obtain a roughened structure, and the roughened structure is used to block the emission of light.

[0013] Preferably, the roughened structure is one or more of a pointed cone, a prism, and a cylinder.

[0014] The roughening structure includes a plurality of roughening monomers with different heights, wherein the height difference between the highest roughening monomer and the lowest roughening monomer is greater than or equal to 2 μm; and the minimum height difference between the root of the roughening structure and the second surface of the substrate layer is greater than or equal to 5 μm.

[0015] Preferably, according to the type of substrate and the preset beam morphology, laser etching is performed on the corresponding area of ​​the second surface of the substrate layer to obtain a corresponding etching pattern, including:

[0016] When the substrate layer is a non-transparent substrate, laser etching is performed on the light emitting area of ​​the second surface of the substrate layer according to a preset beam morphology to obtain a patterned light spot structure on the substrate layer;

[0017] The inner wall of the light spot structure and the surface of the epitaxial layer exposed in the light spot structure are smoothed to obtain an epitaxial wafer with a preset light beam morphology.

[0018] Preferably, the epitaxial layer includes a first conductive semiconductor layer grown on the substrate layer, an active layer grown on the first conductive semiconductor layer, a second conductive semiconductor layer grown on the active layer, and a first electrode electrically connected to the first conductive semiconductor layer and a second electrode electrically connected to the second conductive semiconductor layer.

[0019] Preferably, the steps of manufacturing the epitaxial wafer include:

[0020] A first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are grown on the first surface of the substrate layer and arranged in sequence from bottom to top;

[0021] According to the preset light beam morphology, a light emitting structure with a preset shape is etched on the second conductive semiconductor layer, wherein the light emitting structure extends from the surface of the second conductive semiconductor layer to a certain depth on the first conductive semiconductor layer; and the light emitting structure constitutes the light emitting area;

[0022] Depositing metal in the light-emitting area corresponding to the second conductive semiconductor layer to obtain a second electrode;

[0023] Depositing metal on the first conductive semiconductor layer exposed by the light emitting structure to obtain a first electrode;

[0024] The substrate layer is thinned to obtain the epitaxial wafer.

[0025] Preferably, the substrate layer is thinned to 50-300 microns.

[0026] Preferably, determining the light-emitting area and the non-light-emitting area of ​​the second surface of the substrate layer according to the alignment mark includes:

[0027] Arranging a camera on a side of the epitaxial wafer where the epitaxial layer is disposed, and arranging a laser on a side of the second surface of the substrate layer of the epitaxial wafer;

[0028] The camera sends the acquired alignment mark to the laser controller, and the laser controller calculates the position information of the epitaxial wafer according to a preset algorithm, wherein the position information of the epitaxial wafer includes the light-emitting area and the non-light-emitting area of ​​the epitaxial layer and the light-emitting area and the non-light-emitting area of ​​the second surface of the substrate layer;

[0029] The laser controller controls the laser to perform laser etching in the corresponding area according to the position information of the epitaxial wafer.

[0030] Compared with the prior art, the method for manufacturing a light-emitting diode capable of regulating the light beam morphology of the light-emitting surface proposed by the present invention has the following beneficial effects: for an epitaxial wafer with a transparent or translucent substrate layer, by means of alignment marks, a roughening structure is etched in the non-light-emitting area so that light is emitted only from the light-emitting area, thereby obtaining a preset light beam morphology; and for an epitaxial wafer with a non-transparent substrate layer, by means of alignment marks, a corresponding light-emitting structure is etched in the light-emitting area of ​​the substrate layer to obtain a preset light beam morphology. The present invention can achieve precise control over the formation of light beam morphologies of different epitaxial wafers by setting alignment marks on the side of the epitaxial layer away from the substrate layer and etching corresponding patterns in corresponding areas according to different substrate layer types. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of an epitaxial wafer without forming a first electrode and a second electrode;

[0032] Figure 2 A schematic diagram of the structure of an epitaxial wafer for forming a first electrode and a second electrode;

[0033] Figure 3 It is a schematic diagram of the structure of an epitaxial wafer having a transparent or semi-transparent substrate layer;

[0034] Figure 4 is a schematic diagram of the structure of an epitaxial wafer having a non-transparent substrate layer;

[0035] Reference numerals:

[0036] 10-substrate layer; 100-roughened structure; 110-light emitting structure; 101-first surface; 102-second surface; 11-first conductive semiconductor layer; 12-active layer; 13-second conductive semiconductor layer; 14-first electrode; 15-second electrode;

[0037] 2-camera; 200-luminous area; 210-non-luminous area;

[0038] 3-laser; 300-light-emitting area; 310-non-light-emitting area. DETAILED DESCRIPTION

[0039] The technical solution protected by the present invention is described in detail below with reference to the accompanying drawings.

[0040] The present invention proposes a method for manufacturing a light-emitting diode capable of regulating the beam shape of a light-emitting surface. For substrate layers with different types, a preset beam shape can be etched through laser etching. Specifically, through pre-set alignment marks, a camera is used to identify the corresponding alignment marks to distinguish between a light-emitting area and a non-light-emitting area of ​​the light-emitting surface, and then a laser is used to etch a corresponding pattern in the corresponding area according to the preset beam shape. Not only can a high-precision beam shape of the light-emitting surface be obtained, but the light-emitting diode can also be applied to light-emitting diodes with different requirements, so that the required beam shape can be conveniently manufactured.

[0041] The manufacturing method proposed in the present invention first needs to complete the manufacturing of the epitaxial wafer, please refer to Figure 1 and Figure 2 The epitaxial wafer includes a substrate layer 10 and an epitaxial layer further deposited on the substrate by various epitaxial techniques (such as vapor phase epitaxy and liquid phase epitaxy) on the first surface of the substrate layer 10; the epitaxial layer includes a first conductive semiconductor layer 11 grown on the substrate layer 10, an active layer 12 grown on the first conductive semiconductor layer 11, a second conductive semiconductor layer 13 grown on the active layer 12, a first electrode 14 electrically connected to the first conductive semiconductor layer 11, and a second electrode 15 electrically connected to the P-type semiconductor layer 13; wherein the substrate layer 10 can be a transparent, semi-transparent or non-transparent substrate, and can be made of silicon, sapphire, glass, gallium arsenide, gallium nitride, silicon carbide, lithium aluminate, etc.; the substrate layer 10 includes a first surface on which the epitaxial layer is grown and formed and a second surface 102 opposite to the first surface 101, such as Figure 1 As shown, the upper surface of the substrate layer 10 is the first surface, and the lower surface thereof is the second surface. An epitaxial layer is grown on the first surface, and this side is called the electrode side, and the side facing the second surface is called the light-emitting side. In one embodiment, the first conductive semiconductor layer is an N-type semiconductor layer, and correspondingly, the second conductive semiconductor layer is a P-type semiconductor layer. The active layer is a region that provides light radiation for the recombination of electrons and holes. Different materials can be selected according to different luminescent wavelengths. In one embodiment, the active layer can be a periodic structure of a single quantum well or multiple quantum wells.

[0042] The specific steps for making epitaxial wafers are as follows:

[0043] First, a first conductive semiconductor layer 11, an active layer 12, and a second conductive semiconductor layer 13 are grown on the first surface 101 of the substrate layer 10, which are arranged in sequence from bottom to top; wherein the active layer 12 is a light-emitting layer, which can realize effective recombination of electrons and holes to generate photon emission; Figure 1 The structure shown;

[0044] Next, a light-emitting area with a preset shape and size is formed in the epitaxial layer by wet etching, dry etching or imprinting technology, and etching is performed from the second conductive semiconductor layer 13 toward the first conductive semiconductor layer 11, and the etching stops after a certain depth of the first conductive semiconductor layer 11, thereby forming a light-emitting area I1 with a preset shape including a second conductive semiconductor layer, an active layer and a first conductive semiconductor layer, and then a corresponding conductive electrode is prepared in the light-emitting area. Specifically, a second electrode 15 electrically connected to the second conductive semiconductor layer 13 is made on the second conductive semiconductor layer 13, and the second electrode 15 has a high reflectivity, which is greater than or equal to 80%; at the same time, a first electrode 14 is made on the first conductive semiconductor layer exposed by the etching-formed light-emitting area I1, that is, an LED chip structure with the first electrode 14 and the second electrode 15 on the same side is obtained. Figure 2 The structure shown.

[0045] Then, the substrate layer 10 is thinned. In the present embodiment, the substrate layer 10 is thinned to 50-300 μm, and then the beam shape of the light emitting surface is adjusted. In other embodiments, for the purpose of adjusting the light emitting effect, the substrate layer may not be thinned to have a certain thickness, and then the beam shape of the light emitting surface is adjusted.

[0046] For different types of substrates, the present invention provides different processing methods, such as Figure 3The laser etching process for a transparent or translucent substrate layer 10 is shown. Specifically, a laser is arranged on the light-emitting side of the epitaxial wafer, and a camera for identifying the corresponding alignment mark is arranged on the electrode side thereof, wherein the alignment mark can be a set of graphics, which are formed by processes such as photolithography, etching, and coating during the process, and have a structure with a height difference from the surrounding material for optical identification, and are arranged in each step of the photolithography process; the laser communicates with a laser controller, and the laser controller can receive the alignment mark obtained by the camera, so as to calculate the light-emitting area I1 and the non-light-emitting area I2 of the corresponding epitaxial wafer, and then according to the preset beam morphology, the specific position and shape of the roughened structure that the laser needs to etch can be calculated. Specifically, the laser controller can calculate the second surface 102 of the substrate layer 10 for use The laser etches a corresponding roughening structure 100 in the non-light emitting area O2 according to the set roughening structure in the area (i.e., the light emitting area O1) and the non-light emitting area O2 surrounding the light emitting area. The roughening structure includes a plurality of roughening monomers, and the shapes of the roughening monomers are one or more of the shapes of a pointed cone, a prism, and a cylinder. The heights of the roughening monomers are different, and the corresponding roughening monomers are arranged regularly or irregularly, so that the roughening structure as a whole is uneven; and in order to ensure the effect of blocking the light emission, the height difference between the highest roughening monomer and the lowest roughening monomer should be greater than or equal to 2μm; at the same time, the minimum height between the root of the roughening structure and the second surface of the substrate layer should also be greater than or equal to 5μm. That is, the roughening structure 100 can block the light from being emitted from the laser-processed position, and only emits from the second surface 102 of the substrate layer 10 corresponding to the defined light emitting area, thereby obtaining an accurate preset beam morphology.

[0047] For a non-transparent substrate, such as the substrate layer 10 Figure 4 As shown, in order to obtain a precise light beam morphology, it is necessary to use a laser to etch the light emitting area O1 on the second surface 102 of the substrate layer 10, so as to obtain a patterned spot structure on the substrate layer; the spot structure extends from the second surface 102 to the surface of the first conductive semiconductor layer 11, so that part of the first conductive semiconductor layer 11 is exposed, and then the inner wall of the spot structure and the surface of the first conductive semiconductor layer 11 exposed in the spot structure are smoothed, that is, the light emitted by the LED is emitted through the exposed first conductive semiconductor layer 11 and the opening position of the substrate layer, thereby obtaining an epitaxial wafer with a preset light beam morphology.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface, characterized in that: The steps include: Manufacturing an epitaxial wafer, the epitaxial wafer comprising a substrate layer and an epitaxial layer grown on a first surface of the substrate layer; an alignment mark is provided on a surface of the epitaxial layer away from the substrate layer; the epitaxial layer comprises a light-emitting area and a non-light-emitting area surrounded by the light-emitting area; According to the alignment mark, a light emitting area and a non-light emitting area of ​​the second surface of the substrate layer are determined; the second surface of the substrate is a surface opposite to the first surface of the substrate layer; According to the type of substrate and the preset beam morphology, laser etching is performed on the corresponding area of ​​the second surface of the substrate layer to obtain a corresponding etching pattern; When the substrate layer is a transparent or semi-transparent substrate, laser etching is performed on the non-light-emitting area of ​​the second surface of the substrate layer according to a preset beam shape to obtain a roughened structure, wherein the roughened structure is used to block the emission of light; When the substrate layer is a non-transparent substrate, laser etching is performed on the light emitting area of ​​the second surface of the substrate layer according to a preset beam morphology to obtain a patterned light spot structure on the substrate layer; The inner wall of the light spot structure and the surface of the epitaxial layer exposed in the light spot structure are smoothed to obtain an epitaxial wafer with a preset light beam morphology.

2. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 1, characterized in that: The roughened structure is one or more of a pointed cone, a prism, and a cylinder.

3. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 2, characterized in that: The roughening structure includes a plurality of roughening monomers with different heights, wherein the height difference between the highest roughening monomer and the lowest roughening monomer is greater than or equal to 2 μm; and the minimum height difference between the root of the roughening structure and the second surface of the substrate layer is greater than or equal to 5 μm.

4. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 1, characterized in that: The epitaxial layer includes a first conductive semiconductor layer grown on the substrate layer, an active layer grown on the first conductive semiconductor layer, a second conductive semiconductor layer grown on the active layer, and a first electrode electrically connected to the first conductive semiconductor layer and a second electrode electrically connected to the second conductive semiconductor layer.

5. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 4, characterized in that: The manufacturing steps of the epitaxial wafer include: A first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are grown on the first surface of the substrate layer and arranged in sequence from bottom to top; According to the preset light beam morphology, a light emitting structure with a preset shape is etched on the second conductive semiconductor layer, wherein the light emitting structure extends from the surface of the second conductive semiconductor layer to a certain depth on the first conductive semiconductor layer; and the light emitting structure constitutes the light emitting area; Depositing metal in the light-emitting area corresponding to the second conductive semiconductor layer to obtain a second electrode; Depositing metal on the first conductive semiconductor layer exposed by the light emitting structure to obtain a first electrode; The substrate layer is thinned to obtain the epitaxial wafer.

6. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 5, characterized in that: The substrate layer is thinned to 50-300 microns.

7. The method for manufacturing a light emitting diode capable of adjusting the light beam shape of the light emitting surface according to claim 1, characterized in that: Determining the light-emitting area and the non-light-emitting area of ​​the second surface of the substrate layer according to the alignment mark includes: A camera is arranged on a side of the epitaxial wafer where the epitaxial layer is arranged, and a laser is arranged on a side of the second surface of the substrate layer of the epitaxial wafer; The camera sends the acquired alignment mark to the laser controller, and the laser controller calculates the position information of the epitaxial wafer according to a preset algorithm, wherein the position information of the epitaxial wafer includes the light-emitting area and the non-light-emitting area of ​​the epitaxial layer and the light-emitting area and the non-light-emitting area of ​​the second surface of the substrate layer; The laser controller controls the laser to perform laser etching in the corresponding area according to the position information of the epitaxial wafer.

Images