Wafer, manufacturing method of wafer, light-emitting chip and manufacturing method of light-emitting chip

Abstract

The invention relates to a wafer and a manufacturing method thereof, and a light-emitting chip and a manufacturing method thereof. The wafer comprises a substrate made of a hexagonal crystal material; the light-emitting units are arranged on the substrate, the short edge of each light-emitting unit is parallel to the M-direction crystal orientation of the hexagonal crystal system in the substrate, and the long edge of each light-emitting unit is perpendicular to the M-direction crystal orientation. The manufacturing method of the light-emitting chip comprises the following steps: providing the wafer; and cutting the substrate along the short sides of the light-emitting units and the long sides of the light-emitting units to form a plurality of independent light-emitting chips. The short edge of each light-emitting unit is parallel to the M-direction crystal orientation of the hexagonal system crystal, the processing of cutting and splitting along the M-direction crystal orientation in the subsequent manufacturing process is easier, relatively few laser punching points can be arranged at the part, corresponding to the short edge of the light-emitting chip, on the substrate during subsequent laser implicit cutting, the substrate side surface damage condition of the short edge of the light-emitting chip is improved, and the service life of the light-emitting chip is prolonged. And the light-emitting effect of the light-emitting chip is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a wafer and a manufacturing method, a light-emitting chip and a manufacturing method. Background Art

[0002] Mini LED (Mini Light Emitting Diode, sub-millimeter light-emitting diode), which has the advantages of high brightness, wide color gamut coverage, high contrast, and more saturated colors, has been sought after by various manufacturers.

[0003] At present, in the process of manufacturing Mini LED chips, it is necessary to perform laser hidden cutting and splitting on the produced chip source to form a single light-emitting chip. When the substrate of the chip source is a hexagonal crystal material (such as sapphire crystal), due to the hexagonal crystal structure, the part corresponding to the short side of the light-emitting chip is not easy to be split, and it is necessary to set more laser points on the part corresponding to the short side of the light-emitting chip on the substrate, which causes serious damage to the side of the substrate corresponding to the short side of the light-emitting chip after splitting, affecting the light-emitting effect of the light-emitting chip.

[0004] Therefore, how to improve the damage on the side of the substrate and enhance the light-emitting effect of the light-emitting chip is an urgent problem to be solved. Summary of the invention

[0005] In view of the deficiencies of the above-mentioned related technologies, the purpose of the present application is to provide a wafer and a manufacturing method, a light-emitting chip and a manufacturing method, aiming to solve the technical problem of damage to the side surface of the substrate of the light-emitting chip.

[0006] A wafer comprising:

[0007] A substrate of a hexagonal crystal material;

[0008] A plurality of light-emitting units are arranged on the substrate, wherein the short side of each light-emitting unit is parallel to the A direction of the hexagonal crystal in the substrate, and the long side of each light-emitting unit is parallel to the M direction of the hexagonal crystal in the substrate.

[0009] In the above wafer, the short side of each light-emitting unit is parallel to the M-direction of the hexagonal crystal, which is perpendicular to the M plane. The hexagonal crystal is in a zigzag zigzag shape that is easier to split in this direction, and it is easier to cut and split along the M-direction in the subsequent process. During the subsequent laser hidden cutting, a relatively small number of laser points can be set on the part of the substrate corresponding to the short side of the light-emitting chip, which improves the damage to the substrate side of the short side of the light-emitting chip and improves the light-emitting effect of the light-emitting chip.

[0010] Based on the same inventive concept, the present application also provides a method for manufacturing a wafer, comprising:

[0011] Providing a substrate of hexagonal crystal material, and growing an epitaxial layer on the substrate;

[0012] The epitaxial layer is etched to form a plurality of light-emitting units, wherein the short side of each light-emitting unit is etched along a first direction, and the long side of each light-emitting unit is etched along a second direction, wherein the first direction is parallel to the M-direction of the hexagonal crystal in the substrate, and the second direction is perpendicular to the M-direction.

[0013] In the above-mentioned wafer manufacturing method, the short side of the light-emitting unit is etched along the first direction, and the first direction is parallel to the M-direction of the hexagonal crystal in the substrate, and the M-direction is a direction perpendicular to the M-plane. The hexagonal crystal is in a zigzag-shaped sawtooth surface that is easier to split in this direction, and it is easier to cut and split along the M-direction in the subsequent process. During the subsequent laser hidden cutting, a relatively small number of laser points can be set on the part of the substrate corresponding to the short side of the light-emitting chip, which improves the damage of the substrate side of the short side of the light-emitting chip and improves the light-emitting effect of the light-emitting chip.

[0014] Based on the same inventive concept, the present application also provides a method for manufacturing a light-emitting chip, comprising:

[0015] Providing the wafer as described above;

[0016] The substrate is cut along the short sides of the light emitting units and the long sides of the light emitting units to form a plurality of independent light emitting chips.

[0017] In the above-mentioned method for manufacturing the light-emitting chip, since the short side of the light-emitting unit is parallel to the M-direction of the hexagonal crystal in the substrate, and the hexagonal crystal is in the M-direction, which is a zigzag surface that is easier to crack, it is easier to cut the substrate along the short side of the light-emitting unit, i.e., the M-direction. During laser hidden cutting, a relatively small number of laser points can be set on the part of the substrate corresponding to the short side of the light-emitting chip, which improves the damage to the substrate side of the short side of the light-emitting chip and improves the light-emitting effect of the light-emitting chip.

[0018] Based on the same inventive concept, the present application also provides a light-emitting chip manufactured by the light-emitting chip manufacturing method as described above, comprising:

[0019] A substrate unit of a hexagonal crystal material;

[0020] The light emitting unit is arranged on the substrate unit.

[0021] In the above-mentioned light-emitting chip, the short side of the substrate unit is cut along the M-direction crystal direction. A relatively small number of laser points can be set during the cutting process, which improves the damage of the substrate side on the short side of the light-emitting chip and improves the light-emitting effect of the light-emitting chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a wafer provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the M direction in a hexagonal crystal provided in an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the A direction in a hexagonal crystal provided in an embodiment of the present application;

[0025] Figure 4 Schematic diagram of cutting along the M direction and the A direction provided in the embodiment of the present application;

[0026] Figure 5 A flowchart of a method for manufacturing a wafer provided in another optional embodiment of the present application;

[0027] Figure 6 A schematic diagram of a layout of light-emitting chips provided in another optional embodiment of the present application;

[0028] Figure 7 A flowchart of a method for manufacturing a light-emitting chip provided in yet another optional embodiment of the present application;

[0029] Figure 8 A schematic diagram of positioning two rows of laser focal points on a substrate provided for yet another optional embodiment of the present application;

[0030] Fig. 9 A schematic structural diagram of a light-emitting chip provided in yet another optional embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1-substrate; 2-light-emitting unit; 201-short side; 202-long side; 3-reference flat side; 4-laser focus; 5-layout; 6-substrate unit. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] When the substrate of the source is a hexagonal crystal material, due to the hexagonal crystal structure, the portion corresponding to the short side of the light-emitting chip is not easy to be split, and it is necessary to set more laser points on the substrate corresponding to the short side of the light-emitting chip. As a result, the side of the substrate corresponding to the short side of the light-emitting chip after splitting is severely damaged, affecting the light-emitting effect of the light-emitting chip.

[0036] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0037] The present application embodiment provides a wafer, such as Figure 1 As shown, it includes a substrate 1 and a plurality of light-emitting units 2 arranged on the substrate 1 .

[0038] In this embodiment, the substrate 1 is a hexagonal crystal material. The crystal directions in the structure of the hexagonal crystal include: Figure 2 The M direction perpendicular to the M plane, such as Figure 3 The A direction perpendicular to the A surface, such as Figure 4 As shown, the M-direction in the hexagonal crystal has a zigzag E-shaped sawtooth surface, and the A-direction in the hexagonal crystal has a step-shaped sawtooth surface F-shaped sawtooth surface. Cutting along the zigzag sawtooth surface is easier than cutting along the step-shaped sawtooth surface. In some implementations, the substrate 1 in this embodiment may be sapphire or silicon carbide, or may be other hexagonal crystal materials that can be used as light-emitting chip substrates.

[0039] The light-emitting unit 2 in this embodiment may include an N-type semiconductor layer, a P-type semiconductor layer, and an active layer located between the N-type semiconductor layer and the P-type semiconductor layer. The active layer may include a quantum well layer and may also include other structures. In some embodiments, the light-emitting unit 2 also includes an N-electrode connected to the N-type semiconductor layer and a P-electrode connected to the P-type semiconductor layer. In this embodiment, the material of the N-electrode and the P-electrode is not specifically limited. For example, in some embodiments, the material of the electrode may include but is not limited to at least one of Cr, Ni, Al, Ti, Au, Pt, W, Pb, Rh, Sn, Cu, and Ag.

[0040] In this embodiment, the short side 201 of each light-emitting unit 2 is parallel to the M-direction of the hexagonal crystal in the substrate 1, and the long side 202 of each light-emitting unit 2 is perpendicular to the M-direction. It can be understood that the vertical projection of the light-emitting unit 2 on the substrate 1 in this embodiment is a rectangle, and the vertical projection is also a projection perpendicular to the direction of a side of the substrate 1 away from the light-emitting unit 2. The two short sides 201 of the light-emitting unit 2 correspond to the two shorter sides in the rectangular projection, and the two shorter sides are also parallel to the M-direction of the hexagonal crystal in the substrate 1; the two long sides 202 of the light-emitting unit 2 correspond to the two longer sides in the rectangular projection, and the two longer sides are also perpendicular to the M-direction of the hexagonal crystal in the substrate 1. For the light-emitting chip, the quality of the side wall on the short side 201 of the light-emitting chip will have a greater impact on the light-emitting effect of the light-emitting chip than the quality of the side wall on the long side 202 of the light-emitting chip. Therefore, when manufacturing the light-emitting chip, the processing quality of the side wall on the short side 201 of the light-emitting chip must be ensured. In this embodiment, the light-emitting chip emits light from the side where the substrate 1 is set.

[0041] In some embodiments, Figure 1 As shown, a reference flat edge 3 may be provided on the substrate 1 in this embodiment, and the short side 201 of the light-emitting unit 2 is perpendicular to the reference flat edge 3. In some embodiments, a certain portion on the circumference of the sapphire substrate 1 may be cut, and the cut edge is the reference flat edge 3. During the manufacturing process, the reference flat edge 3 may be used as a criterion for determining the crystal orientation of the M direction in the hexagonal crystal, making the manufacturing process easier and avoiding mis-processing. In other embodiments, other structures that can serve as a reference for the crystal orientation of the M direction may also be provided on the substrate 1, such as arrows, lines, grooves, bosses, etc.

[0042] In some embodiments, grid-shaped dot marks are set in the substrate 1 by laser hidden cutting, one light-emitting unit 2 corresponds to one grid, and the long side 202 of the light-emitting unit 2 corresponds to at least two rows of dot marks. It can be understood that the dot marks formed by laser hidden cutting are in a grid shape, and one light-emitting unit 2 corresponds to one grid, which can facilitate the subsequent use of the wafer. When used, multiple independent light-emitting chips can be formed by directly splitting along the grid-shaped dot marks. In addition, the long side 202 of the light-emitting unit 2 corresponds to at least two rows of dot marks, which can solve the problem of oblique cracking of the corresponding parts of the long side 202 of the substrate 1 and the light-emitting unit 2 during subsequent splitting. Because the long side 202 of the light-emitting unit 2 is perpendicular to the M-direction crystal direction, oblique cracking is prone to occur when cutting along this direction, and this problem can be solved by setting at least two rows of dot marks, which improves the color cast problem of the long sides 202 on both sides of the light-emitting surface of the light-emitting chip produced later, and can also make the sides of the short side 201 of the light-emitting chip nearly rectangular, further optimizing the light-emitting effect of the light-emitting chip. In this embodiment, the light emitting surface of the light emitting chip is a surface of the substrate 1 away from the light emitting unit 2 .

[0043] In the above wafer, the short side 201 of each light emitting unit 2 is parallel to the M direction of the hexagonal crystal, and the M direction is a direction perpendicular to the M plane. Figure 4 As shown, the hexagonal crystal presents a zigzag surface of the fold line E that is easier to split in this direction, and it is easier to cut and split along the M direction crystal direction in the subsequent process. During the subsequent laser hidden cutting, a relatively small number of laser points can be set on the portion of the substrate 1 corresponding to the short side 201 of the light-emitting chip, which improves the side damage of the substrate 1 on the short side 201 of the light-emitting chip and improves the light-emitting effect of the light-emitting chip. Moreover, there will be no oblique cracking phenomenon when the side of the substrate 1 is formed by cutting along the M direction crystal direction. The side wall of the short side 201 of the light-emitting chip formed by cutting is almost perpendicular to the surface of the substrate 1. The short sides 201 on both sides of the top light-emitting surface of the light-emitting chip will not have the problem of color cast, which optimizes the light-emitting effect of the light-emitting chip.

[0044] Another optional embodiment of the present application:

[0045] This embodiment provides a method for manufacturing a wafer, such as Figure 5 As shown, the following steps are included:

[0046] S101: providing a substrate of a hexagonal crystal material, and growing an epitaxial layer on the substrate 1 .

[0047] The substrate 1 in this embodiment may be sapphire or silicon carbide, or may be other hexagonal crystal materials that can be used as the light-emitting chip substrate 1. The epitaxial layer in this embodiment includes at least an N-type semiconductor layer, a P-type semiconductor layer, and an active layer located between the N-type semiconductor layer and the P-type semiconductor layer.

[0048] S102: etching the epitaxial layer to form a plurality of light-emitting units, wherein the short side of each light-emitting unit is etched along a first direction, and the long side of each light-emitting unit is etched along a second direction.

[0049] In this embodiment, the first direction is parallel to the M direction of the hexagonal crystal in the substrate 1, and the second direction is perpendicular to the M direction of the hexagonal crystal in the substrate 1. In this embodiment, the epitaxial layer is etched to form a plurality of light-emitting units 2, which can be specifically arranged by the following steps:

[0050] like Figure 6 As shown, the epitaxial layer is subjected to light-emitting chip Figure 5 Arrangement, layout version Figure 5 In the embodiment, the short side 201 of the light emitting chip is parallel to the M direction of the hexagonal crystal in the substrate 1, and the long side 202 of each light emitting chip is perpendicular to the M direction;

[0051] Re-edition Figure 5 The short side 201 and the long side 202 of the light-emitting chip are etched to form a plurality of light-emitting units 2. In this embodiment, the etching process can specifically adopt a dry etching process, and before the etching process of the epitaxial layer, it can also include steps such as setting a mask, performing exposure and development. In addition, the epitaxial layer can be further processed by evaporation, etching, deposition and other processes to form a light-emitting unit 2 with an N electrode and a P electrode.

[0052] After forming a plurality of light-emitting units 2, the method may further include:

[0053] The substrate 1 is laser cut to form grid-like dot marks, and one light-emitting unit 2 corresponds to one grid, and the long side 202 of the light-emitting unit 2 corresponds to at least two rows of dot marks. When in use, multiple independent light-emitting chips can be formed by directly splitting along the grid-like dot marks, which is convenient for the subsequent use of the wafer. Moreover, the long side 202 of the light-emitting unit 2 corresponds to at least two rows of dot marks, which can solve the problem of oblique cracking of the corresponding parts of the long side 202 of the substrate 1 and the light-emitting unit 2 during subsequent splitting. Because the long side 202 of the light-emitting unit 2 is perpendicular to the M-direction crystal direction, oblique cracking is prone to occur when cutting along this direction, and this problem can be solved by setting at least two rows of dot marks, which improves the color cast problem of the long sides 202 on both sides of the light-emitting surface of the light-emitting chip produced later, and can also make the side surfaces on both sides of the short side 201 of the light-emitting chip nearly rectangular, further optimizing the light-emitting effect of the light-emitting chip. In this embodiment, the light-emitting surface of the light-emitting chip is the side of the substrate 1 away from the light-emitting unit 2.

[0054] In the above wafer manufacturing method, the short side 201 of the light emitting unit 2 is etched along a first direction, and the first direction is parallel to the M direction of the hexagonal crystal in the substrate 1, and the M direction is a direction perpendicular to the M plane. Figure 4As shown, the hexagonal crystal presents a zigzag surface of the fold line E that is easier to split in this direction, and it is easier to cut and split along the M direction crystal direction in the subsequent process. During the subsequent laser hidden cutting, a relatively small number of laser points can be set on the portion of the substrate 1 corresponding to the short side 201 of the light-emitting chip, which improves the side damage of the substrate 1 on the short side 201 of the light-emitting chip and improves the light-emitting effect of the light-emitting chip. Moreover, there will be no oblique cracking phenomenon when the side of the substrate 1 is formed by cutting along the M direction crystal direction. The side wall of the short side 201 of the light-emitting chip formed by cutting is almost perpendicular to the surface of the substrate 1. The short sides 201 on both sides of the top light-emitting surface of the light-emitting chip will not have the problem of color cast, which optimizes the light-emitting effect of the light-emitting chip.

[0055] Another optional embodiment of the present application:

[0056] The present application provides a method for manufacturing a light-emitting chip. Figure 7 As shown, the following steps are included:

[0057] S201: Provide a wafer.

[0058] The wafer in this embodiment is the wafer shown in the above embodiment, and will not be described in detail here.

[0059] S202: cutting the substrate along the short sides of the light-emitting units and the long sides of the light-emitting units to form a plurality of independent light-emitting chips.

[0060] In some implementations, cutting the substrate 1 to form a plurality of independent light-emitting chips includes:

[0061] The laser focus 4 of the laser hidden cutting is positioned along the short side 201 of the light emitting unit 2 and the long side 202 of the light emitting unit 2, and the substrate 1 is laser hidden cut according to the positioned laser focus 4, wherein, Figure 8 As shown, the long side 202 of each light emitting unit 2 respectively positions at least two rows of laser focal points 4. It can be understood that in this embodiment, laser dotting can be performed on the substrate 1 once one laser focal point 4 is positioned.

[0062] Finally, the substrate 1 is split to form a plurality of independent light-emitting chips.

[0063] It can be understood that the laser focal points 4 positioned on the long sides 202 of each light emitting unit 2 are all located in the substrate 1, and specifically can be two rows, three rows or more. Each row of laser focal points 4 positioned on a long side 202 is located on the same plane and parallel to each other, and each row of laser focal points 4 is arranged in a direction parallel to the surface of the substrate 1.

[0064] Because the long side 202 of the light-emitting unit 2 is perpendicular to the M-direction crystal direction, oblique cracking is prone to occur when cutting along this direction. By positioning at least two rows of laser focus points 4 at positions corresponding to the long sides 202 of the light-emitting unit 2 on the substrate 1, the problem of oblique cracking of the corresponding parts of the substrate 1 and the long sides 202 of the light-emitting unit 2 during splitting can be solved, the problem of color cast of the long sides 202 on both sides of the top light-emitting surface of the light-emitting chip is improved, and the side surfaces on both sides of the short sides 201 of the light-emitting chip can be made nearly rectangular, further optimizing the light-emitting effect of the light-emitting chip.

[0065] In some embodiments, positioning the laser focus 4 of the laser hidden cutting along the short side 201 of the light emitting unit 2 and the long side 202 of the light emitting unit 2 includes:

[0066] At least two rows of laser focal points 4 are respectively positioned along the short sides 201 of each light emitting unit 2 .

[0067] At least two rows of laser focal points 4 are also positioned on the portion of the substrate 1 corresponding to the short side 201 of the light emitting unit 2, which is more conducive to the splitting of the portion of the substrate 1 corresponding to the short side 201 of the light emitting unit 2, so that the side morphology of the short side 201 of the light emitting chip formed after splitting is better and more conducive to light emission. In some application scenarios, only one row of laser focal points 4 can be positioned along the short side 201 of each light emitting unit 2, and one row of laser focal points 4 can also achieve splitting.

[0068] In one embodiment, if Figure 8 As shown, two rows of laser focuses 4 may be positioned along the long side 202 of each light emitting unit 2 and the short side 201 of the light emitting unit 2, respectively. The two rows of laser focuses 4 are stacked in a direction perpendicular to the bottom surface of the substrate 1, and the distance between one row of laser focuses 4 and the bottom surface is less than 1 / 2 of the thickness of the substrate 1, and the distance between the other row of laser focuses 4 and the bottom surface of the substrate 1 is greater than 1 / 2 of the thickness of the substrate 1, which is more conducive to the subsequent splitting process. The bottom surface of the substrate 1 is the side away from the light emitting unit 2, and the thickness of the substrate 1 is the thickness of the substrate 1 in a direction perpendicular to its bottom surface.

[0069] In the above-mentioned method for manufacturing the light-emitting chip, since the short side 201 of the light-emitting unit 2 is parallel to the M direction of the hexagonal crystal in the substrate 1, Figure 4As shown, the hexagonal crystal presents a zigzag surface of the folded line E that is easier to crack in the M-direction crystal direction, and it is easier to cut the substrate 1 along the short side 201 of the light-emitting unit 2, that is, the M-direction crystal direction. During laser hidden cutting, a relatively small number of laser points can be set on the portion of the substrate 1 corresponding to the short side 201 of the light-emitting chip, which improves the side damage of the substrate 1 on the short side 201 of the light-emitting chip and improves the light-emitting effect of the light-emitting chip. Moreover, there will be no oblique cracking on the side of the substrate 1 formed by cutting along the M-direction crystal direction. The side wall of the short side 201 of the light-emitting chip formed by cutting is almost perpendicular to the surface of the substrate 1. The short sides 201 on both sides of the light-emitting chip top light-emitting surface will not have the problem of color cast, which optimizes the light-emitting effect of the light-emitting chip.

[0070] Another optional embodiment of the present application:

[0071] This embodiment provides a light-emitting chip manufactured by the light-emitting chip manufacturing method as described above. Fig. 9 As shown, it includes a substrate unit 6 made of a hexagonal crystal material, and a light-emitting unit 2 arranged on the substrate unit 6 .

[0072] The substrate units 6 in this embodiment are formed by splitting the substrate 1 in the above embodiment, and are independent of each other and correspond one to one with the light-emitting units 2. The substrate 1 in this embodiment can be sapphire or silicon carbide, or can also be other hexagonal crystal materials that can be used as the light-emitting chip substrate 1. The light-emitting units 2 in this embodiment are the same as those in the above embodiment, and will not be described one by one here.

[0073] The light-emitting chip in this embodiment may be a micro LED chip, for example including but not limited to Mini LED (MiniLight Emitting Diode, sub-millimeter light-emitting diode), Micro LED (Micro Light Emitting Diode, micrometer-scale light-emitting diode), nanometer-scale light-emitting diode, and the like.

[0074] In some embodiments, the substrate unit 6 in this embodiment may have at least two rows of hidden laser cutting marks on the side corresponding to the long side 202 of the light emitting unit 2. By positioning at least two rows of laser focus points 4 at the position corresponding to the long side 202 of the light emitting unit 2 on the substrate 1 for processing, the problem of oblique cracking of the corresponding part of the substrate 1 and the long side 202 of the light emitting unit 2 during cleavage can be solved, the problem of color cast of the long sides 202 on both sides of the top light emitting surface of the light emitting chip can be improved, and the side surfaces on both sides of the short side 201 of the light emitting chip can be made nearly rectangular, further optimizing the light emitting effect of the light emitting chip.

[0075] In the above-mentioned light-emitting chip, the short side 201 of the substrate unit 6 is cut along the M-direction crystal direction. A relatively small number of laser points can be set during the cutting process, which improves the damage of the side surface of the substrate 1 on the short side 201 of the light-emitting chip, and the side morphology of the short side 201 of the light-emitting chip is better, thereby improving the light-emitting effect of the light-emitting chip. Moreover, there will be no oblique cracking phenomenon when the side surface of the substrate 1 is cut along the M-direction crystal direction. The side wall of the short side 201 of the light-emitting chip formed by the cutting is almost perpendicular to the surface of the substrate 1. The short sides 201 on both sides of the top light-emitting surface of the light-emitting chip will not have the problem of color cast, thereby optimizing the light-emitting effect of the light-emitting chip.

[0076] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A wafer, characterized in that: include: A substrate of a hexagonal crystal material; A plurality of light-emitting units are arranged on the substrate, wherein the short side of each of the light-emitting units is parallel to the M-direction of the hexagonal crystal in the substrate, and the long side of each of the light-emitting units is perpendicular to the M-direction.

2. The wafer according to claim 1, characterized in that The substrate comprises a sapphire substrate, a reference flat edge is arranged on the sapphire substrate, and a short side of the light emitting unit is perpendicular to the reference flat edge.

3. The wafer according to claim 1 or 2, characterized in that: The substrate is provided with grid-shaped dot marks by laser hidden cutting, one light-emitting unit corresponds to one grid, and the long side of the light-emitting unit corresponds to at least two rows of dot marks.

4. A method for manufacturing a wafer, characterized in that: include: Providing a substrate of hexagonal crystal material, and growing an epitaxial layer on the substrate; The epitaxial layer is etched to form a plurality of light-emitting units, wherein the short side of each light-emitting unit is etched along a first direction, and the long side of each light-emitting unit is etched along a second direction, wherein the first direction is parallel to the M-direction of the hexagonal crystal in the substrate, and the second direction is perpendicular to the M-direction.

5. A method for manufacturing a light-emitting chip, characterized in that: include: Providing a wafer as described in any one of claims 1 to 3; The substrate is cut along the short sides of the light emitting units and the long sides of the light emitting units to form a plurality of independent light emitting chips.

6. The method for manufacturing a light emitting chip according to claim 5, characterized in that: The step of cutting the substrate to form a plurality of independent light-emitting chips comprises: Positioning laser focal points of laser hidden cutting along the short sides of the light-emitting units and the long sides of the light-emitting units, and performing laser hidden cutting on the substrate according to the positioned laser focal points, wherein at least two rows of laser focal points are positioned on the long sides of each of the light-emitting units; The substrate is split to form a plurality of independent light-emitting chips.

7. The method for manufacturing a light-emitting chip according to claim 6, wherein the step of positioning the laser focus of the laser hidden cutting along the short side of the light-emitting unit and the long side of the light-emitting unit comprises: At least two rows of laser focal points are respectively positioned along the short sides of each of the light emitting units.

8. The method for manufacturing a light emitting chip according to claim 7, characterized in that: Positioning the laser focus of the laser hidden cutting along the short side of the light emitting unit and the long side of the light emitting unit comprises: Two rows of the laser focus are positioned along the long side of each of the light-emitting units and the short side of the light-emitting units, respectively, and the two rows of the laser focus are stacked in a direction perpendicular to the bottom surface of the substrate, and the distance between one row of the laser focus and the bottom surface is less than 1 / 2 of the thickness of the substrate, and the distance between the other row of the laser focus and the bottom surface is greater than 1 / 2 of the thickness of the substrate, and the bottom surface of the substrate is a side away from the light-emitting unit.

9. A light-emitting chip manufactured by the method for manufacturing a light-emitting chip according to any one of claims 5 to 8, characterized in that: include: Substrate unit of hexagonal crystal material; The light emitting unit is arranged on the substrate unit.

10. The light emitting chip according to claim 9, characterized in that: The side surface of the substrate unit corresponding to the long side of the light emitting unit has at least two rows of laser hidden cutting dot marks.

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