Light emitting chip manufacturing method and light emitting chip

Abstract

The application discloses a light emitting chip manufacturing method, which comprises the following steps: growing an epitaxial layer on a first surface of a growth substrate, forming a plurality of holes for accommodating light color conversion materials in the epitaxial layer, growing a light emitting structure for generating excitation light on a second surface of the growth substrate, and filling the holes with the light color conversion materials, so that the excitation light generated by the light emitting structure is converted from a first light color to a second light color and emitted.

Description

Technical Field

[0001] This invention relates to the field of display technology, and specifically to a method for manufacturing a light-emitting chip and the light-emitting chip itself. Background Technology

[0002] Due to their excellent energy-saving effect and high brightness, LED chips have become the most valued light source technology in recent years and are widely used in various industries of production and daily life.

[0003] In existing technologies, LED chips are typically made of gallium nitride (GaN). GaN-based LED chips can only emit blue and green light, not other colors like red, which doesn't meet application requirements. Therefore, when applying LED chips to the display field, a red LED chip from an AlInGaP quaternary system is needed to display full-color images. However, in small-pitch or micro-pitch LED displays, especially in fully flip-chip COB (chip-on-board) products, the cost of producing low-yield flip-chip red LED chips is high, and the chips are difficult to further miniaturize. Therefore, an alternative solution using quantum dots for color conversion to emit red light has been proposed. However, this solution faces reliability issues, such as the potential for the color conversion structure to detach. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing light-emitting chips that is simple in process and low in cost, as well as a light-emitting chip manufactured using this method.

[0005] To achieve the above objectives, the present invention provides a method for manufacturing a light-emitting chip, comprising:

[0006] An epitaxial layer is grown on the first surface of the growth substrate;

[0007] A light-emitting structure is grown on the second side of the growth substrate, the light-emitting structure being used to generate excitation light, the second side being opposite to the first side;

[0008] Multiple pores are formed in the epitaxial layer, and the pores are used to accommodate light-color conversion material;

[0009] The hole is filled with a light-color conversion material, which is used to convert the excitation light from a first light color to a second light color.

[0010] In some embodiments, the material of the epitaxial layer is different from the material of the growth substrate, and the structural layer in contact with the second surface of the light-emitting structure and the growth substrate is made of the same material as the epitaxial layer.

[0011] In some embodiments, the growth substrate is a sapphire substrate, and the epitaxial layer is a GaN epitaxial layer.

[0012] In some embodiments, growing an epitaxial layer on the first side of the growth substrate includes: growing a rough epitaxial layer on the growth substrate using hydride vapor phase epitaxy at a temperature of 880-980°C, a ratio of group V elements to group III elements of 10-50, and a high pressure of 400-650 torr.

[0013] In some embodiments, growing an epitaxial layer on the first side of the growth substrate includes: growing a flat n-type or p-type doped epitaxial layer on the growth substrate using hydride vapor phase epitaxy in a temperature environment of 1000-1050°C, a ratio of group V elements to group III elements greater than 50, a low pressure environment of 100-350 torr, and passing a dopant.

[0014] In some embodiments, if the light-emitting structure is first grown on the second side of the growth substrate and then the plurality of holes are formed on the epitaxial layer, the method further includes covering the light-emitting structure with a protective material to prevent corrosion of the light-emitting structure before the plurality of holes are formed on the epitaxial layer.

[0015] In some embodiments, after one of the epitaxial layer and the light-emitting structure is grown on the growth substrate, the thickness of the growth substrate is reduced, and then the other of the epitaxial layer and the light-emitting structure is grown on the growth substrate.

[0016] In some embodiments, after filling the holes with a light-color conversion material, the method further includes: covering the epitaxial layer with a filter structure, the filter structure covering the light-emitting side of the epitaxial layer except for the area corresponding to the holes, the filter structure preventing the transmission of light of the first color.

[0017] In some embodiments, after filling the holes with a light-color conversion material, the method further includes covering the light-color conversion material with a protective structure to prevent moisture and oxygen from contacting the light-color conversion material, thereby enhancing the lifespan and reliability of the light-color conversion material.

[0018] In some embodiments, the epitaxial layer includes a plurality of sub-epitaxy layers; each sub-epitaxy layer includes a growth end and an extension end opposite to each other, the growth end being disposed in contact with the growth substrate and the extension end being disposed away from the growth substrate; the plurality of sub-epitaxy layers are grown at intervals on a first surface of the growth substrate.

[0019] To achieve the above objectives, the present invention also provides a light-emitting chip, which is manufactured using the light-emitting chip manufacturing method described above.

[0020] The method for fabricating a light-emitting chip provided by this invention involves growing an epitaxial layer on a first surface of a growth substrate, forming multiple holes in the epitaxial layer to accommodate a light-color conversion material, and growing a light-emitting structure on a second surface of the growth substrate to generate excitation light. The excitation light generated by the light-emitting structure is then converted from a first color to a second color by filling the holes with the light-color conversion material. This method is applicable to fabricating complex light-emitting chips using existing techniques, such as flip-chip red light-emitting chips, using a light-emitting structure with a simple fabrication process, thereby simplifying the fabrication process and reducing manufacturing costs. Furthermore, since this invention grows the epitaxial layer and the light-emitting structure on two opposite surfaces of the growth substrate, there is no need for an additional step to fix the light-emitting surfaces of the light-color conversion material layer and the light-emitting structure, reducing the number of process steps. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process of fabricating a light-emitting chip according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of part of the process of a method for manufacturing a light-emitting chip according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of part of the process of a method for manufacturing a light-emitting chip according to another embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of a light-emitting structure fabricated according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of a light-emitting chip manufactured according to an embodiment of the present invention. Detailed Implementation

[0026] To explain in detail the content, structural features, objectives, and effects of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] In the description of this invention, it should be understood that the terms "upper," "lower," "vertical," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only used for the convenience of describing this invention and simplifying the description, and therefore should not be construed as limiting the scope of protection of this invention.

[0028] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

[0029] Please see Figure 1An embodiment of the present invention provides a method for manufacturing a light-emitting chip, comprising the following steps S1 to S5.

[0030] S1, an epitaxial layer 2 is grown on the first surface of the growth substrate 1, such as Figure 1 As shown in (a).

[0031] Specifically, the growth substrate 1 can be, for example, a sapphire substrate, and the epitaxial layer 2 can be, for example, a gallium nitride (GaN) epitaxial layer. The growth method of the epitaxial layer 2 can be MBE (molecular beam epitaxy), MOCVD (metal-organic chemical vapor deposition), HVPE (hydride vapor phase epitaxy), etc.

[0032] In this embodiment, a rough epitaxial layer 2 is grown on the first surface of the growth substrate 1 using hydride vapor phase epitaxy (HVPE) at a temperature of 880-980°C, a ratio of Group V to Group III elements of 10-50, and a high pressure of 400-650 torr. The rough epitaxial layer 1 is easy to etch in order to form holes 20 by performing the following step S3.

[0033] In one embodiment, a flat n-type doped epitaxial layer 2 is grown on the first surface of a growth substrate 1 using hydride vapor phase epitaxy under a temperature environment of 1000-1050°C, a ratio of group V elements to group III elements greater than 50, a low-pressure environment of 100-350 torr, and with the dopant silane introduced. During the etching process, the locations of the doped atoms are etched preferentially.

[0034] In this embodiment, an epitaxial layer 2 with an integral structure is formed on the first surface of the growth substrate 1, such as... Figure 1 As shown.

[0035] In some embodiments, a dam 21 located at the edge can be grown on the first surface of the growth substrate 1 using techniques such as masking. Figure 2 As shown in (a1), then, multiple interstitial sub-epithelial layers are grown within the space enclosed by the dam 21, as shown in... Figure 2As shown in (a2), the sub-epitaxial layer can be a protrusion 22, and the protrusion 22 and the dam 21 constitute the epitaxial layer 2. Alternatively, the dam 21 located at the edge position and multiple protrusions 22 with gaps are grown in one step on the first surface of the growth substrate 1 using techniques such as masking. Alternatively, multiple sub-epitaxial layers with gaps are grown on the first surface of the growth substrate 1 using techniques such as masking, and the multiple sub-epitaxial layers constitute the epitaxial layer 2. In the next step S3, the protrusions 22 / sub-epitaxial layers are further etched to obtain the holes 20 for accommodating the light color conversion material 4. In addition, multiple first protrusions 21 with gaps are grown on the first surface of the growth substrate 1 first, such as Figure 3 As shown in (a1), then, a second protrusion 22 is grown in the gap between each of the first protrusions 21, as shown in (a1). Figure 3 As shown in (a2), the first protrusion 21 and the second protrusion 22 constitute the epitaxial layer 2. In the next step S3, the first protrusion 21 and / or the second protrusion 22 are further etched to obtain the hole 20 for accommodating the light color conversion material 4. Since there are gaps between each protrusion 22 / sub-epitaxial layer, the stress between each protrusion 22 / sub-epitaxial layer will not be transmitted to each other, which can avoid the epitaxial layer 2 from being completely crushed due to etching damage to part of the structure.

[0036] like Figure 2 , Figure 3 The epitaxial layer 2 shown is a split structure. By etching the part of the protrusion 22 near the gap, or etching the part of the first protrusion 21 and / or the second protrusion 22 near the gap, the hole 20 is formed, which can avoid the epitaxial layer 2 from being completely crushed due to etching damage to part of the structure.

[0037] S2, a light-emitting structure 3 is grown on the second surface of the growth substrate 1, such as Figure 1 As shown in (b), the second side of the growth substrate 1 is the side of the growth substrate 1 opposite to the first side, and the light-emitting structure 3 is used to generate excitation light.

[0038] Specifically, firstly, an epitaxial layer structure of the light-emitting structure 3 is grown on the second side of the growth substrate 1 using metal-organic chemical vapor deposition (MOCVD), and then chip fabrication is performed. The light-emitting structure 3 after chip fabrication can be a right-side-mounted structure or a flip-chip structure. In this embodiment, the light-emitting structure 3 is a flip-chip structure.

[0039] In one embodiment, the flip-chip light-emitting chip includes a growth substrate, a buffer layer, an intrinsic semiconductor layer, an N-type epitaxial layer, a light-emitting layer, and a P-type epitaxial layer arranged sequentially. The side of the N-type epitaxial layer facing away from the intrinsic semiconductor layer and the side of the P-type epitaxial layer facing away from the N-type epitaxial layer are respectively provided with a P-type electrode and an N-type electrode.

[0040] like Figure 4As shown, the light-emitting structure 3 grown in one embodiment of the present invention includes a GaN buffer layer 31, an intrinsic semiconductor layer 32, an N-type GaN epitaxial layer 33, a light-emitting layer 34, and a P-type GaN epitaxial layer 35 arranged sequentially. An N-type electrode 36 is provided on the side of the N-type GaN epitaxial layer 33 facing away from the intrinsic semiconductor layer 32, and a P-type electrode 37 is provided on the side of the P-type GaN epitaxial layer 35 facing away from the N-type GaN epitaxial layer 33.

[0041] In embodiments where the material of the epitaxial layer 2 is different from that of the growth substrate 1, and the material of the structural layer in contact with the second side of the growth substrate 1 is also different from that of the growth substrate 1, for example, where the growth substrate 1 is a sapphire substrate, the epitaxial layer 2 is a GaN epitaxial layer, and the light-emitting structure 3 includes a GaN buffer layer, an intrinsic semiconductor layer, an N-type GaN epitaxial layer, a light-emitting layer, and a P-type GaN epitaxial layer sequentially stacked on the second side of the growth substrate 1, in step S1, when the epitaxial layer 2 is grown on the first side of the growth substrate 1, the growth substrate 1 will bend after the epitaxial layer 2 is grown because the material of the epitaxial layer 2 is different from that of the growth substrate 1; while in step S2, when the light-emitting structure 3 is grown on the second side of the growth substrate 1, the light-emitting structure 3 will cause the growth substrate 1 to bend in the opposite direction, which can compensate for the bending caused by the growth of the epitaxial layer 2 in step S1. Therefore, the growth substrate 1 of the final light-emitting chip is relatively flat. In this embodiment, the materials of the structural layer and the epitaxial layer 2 that are in contact with the second surface of the light-emitting structure 3 and the growth substrate 1 can be the same or different, as long as the growth substrate 1 can be bent in the direction of the structural layer or the epitaxial layer 2 that are in contact with the second surface of the growth substrate 1 during the growth process.

[0042] S3, Multiple pores 20 are formed in the epitaxial layer 2. The pores 20 are used to accommodate the light-color conversion material 4, such as... Figure 1 As shown in (c).

[0043] Specifically, the epitaxial layer 2 can be etched using electrochemical corrosion or other etching methods to form the holes 20.

[0044] S4, fill the hole 20 with light color conversion material 4. The light color conversion material 4 is used to convert the excitation light from the first light color to the second light color for emission, such as... Figure 1 As shown in (d).

[0045] The light-color conversion material 4 can be any material that can fill the pores 20 and convert the first light color into the second light color, such as quantum dots, phosphors, etc. The second light color and the first light color are not limited to a specific light color. In some embodiments, the second light color is red light and the first light color is blue light; in some embodiments, the second light color can be red light and the first light color can be green light, etc. The second light color can also be any light color other than red light.

[0046] S5, a filter structure 5 is applied to the epitaxial layer 2. The filter structure 5 covers the area of ​​the epitaxial layer 2 on the light-emitting side except for the area corresponding to the hole 20 (i.e., the upper surface of the epitaxial layer 2). Figure 1 (Taking the angle shown as an example) There is no area directly opposite hole 20, such as Figure 1 As shown in (e), the filter structure 5 blocks the transmission of light of the first color. Of course, in some embodiments, the filter structure 5 may also cover the entire light-emitting side of the epitaxial layer 2, as long as the filter structure 5 does not affect the transmission of light of the second color and blocks the transmission of light of the first color.

[0047] In the above embodiment, the light-emitting structure 3 is first grown on the second surface of the growth substrate 1, and then multiple holes 20 are formed in the epitaxial layer 2. This utilizes the fact that the epitaxial layer 2 continuously and slowly decomposes due to poor ammonia gas flow during the growth of the light-emitting structure 3, further increasing the roughness of the epitaxial layer 2, which facilitates etching to form the holes 20 in step S3. It can be understood that in some embodiments, multiple holes 20 may be formed in the epitaxial layer 2 first, and then the light-emitting structure 3 may be grown on the second surface of the growth substrate 1; that is, step S3 is performed first, followed by step S2.

[0048] In the above embodiments, the epitaxial layer 2 is first grown on the first surface of the growth substrate 1, and then the light-emitting structure 3 is grown on the second surface of the growth substrate 1. This is to avoid damaging the already grown light-emitting structure 3 during the growth of the epitaxial layer 2 when the light-emitting structure 3 is grown first. Of course, in some embodiments, the light-emitting structure 3 can also be grown on the second surface of the growth substrate 1 first, and then protected, before the epitaxial layer 2 is grown on the first surface of the growth substrate 1. That is, step S2 is performed first, and then step S1 is performed.

[0049] In some embodiments, before step S1, a heat insulation layer may be formed on the first side of the growth substrate 1 to block the heat emitted when the light-emitting structure 3 is lit, and to protect the light color conversion material 4.

[0050] In some embodiments, after performing step S1 and before performing step S2, the thickness of the growth substrate 1 is further reduced through thinning, grinding, and polishing processes to reduce the thickness of the final fabricated light-emitting chip. Simultaneously, this also allows the light-emitting area of ​​the fabricated light-emitting chip to be closer to the surface area of ​​the light-emitting side of the chip (within a certain range). Figure 1 Taking the angle shown as an example, it represents the area of ​​the upper surface of the light-emitting chip.

[0051] In some embodiments, after step S2, step S3 is performed to cover the light-emitting structure 3 with a protective material, such as wax, before the formation of a plurality of holes 20 in the epitaxial layer 2, in order to prevent corrosion of the light-emitting structure 3 during the etching of the epitaxial layer 2 to form the holes 20.

[0052] In some embodiments, after step S5, a protective layer is also applied to the light color conversion material 4 to block water vapor and oxygen, thereby protecting the light color conversion material 4.

[0053] Since the etching process of the epitaxial layer 2 to form the hole 20 may damage the epitaxial layer 2 and / or the growth substrate 1, the damaged area will refract light and change the light emission angle. Therefore, in some embodiments, the filling amount of the light color conversion material 4 is adjusted according to the light refraction of the growth substrate 1 so that the light emission intensity of the area of ​​the light emission side of the epitaxial layer 2 facing the hole 20 is equal to the light emission intensity of the area of ​​the light emission side of the epitaxial layer 2 other than the area facing the hole 20 (for ease of description, the area of ​​the light emission side of the epitaxial layer 2 facing each hole 20 is referred to as the first area, and each area of ​​the light emission side of the epitaxial layer 2 that does not face the hole 20 is referred to as the second area), so that the light-emitting chip emits light uniformly.

[0054] Specifically, the amount of light-color conversion material 4 filling each hole 20 is determined based on the following relationship.

[0055]

[0056] Among them, L 膜 L represents the brightness of a second region (the region on the light-emitting side of epitaxial layer 2 directly opposite a hole 20) measured vertically. 量 The brightness of a first region (a region on the light-emitting side of epitaxial layer 2 that is not directly opposite the hole 20) measured vertically is given. If the epitaxial layer 2 and / or the growth substrate 1 are damaged, the slope of a certain wound will refract the light emitted by the light-emitting structure 3, causing an angle θ (e.g., ...) that deviates from the original emission angle. Figure 5 As shown, the light deviates from the L1 direction to the L2 direction, and the angle between L1 and L2 is θ). 伤n This represents the area of ​​the inclined plane in the wound that refracts light, such as... Figure 5 S shown 伤1 S 伤2 S 量 This represents the area of ​​the light-color conversion material 4 filling the hole 20. This represents the brightness corresponding to the average area of ​​the light-color conversion material 4. Because the light travels a longer distance after its direction is changed due to refraction by the inclined plane of the wound, the intensity of the refracted light is reduced to... Since the direction of light emission deviates from the vertical after refraction, the luminous intensity measured in the vertical direction is expressed as:

[0057] In summary, the light-emitting chip fabrication method provided by this invention involves growing an epitaxial layer 2 on the first surface of a growth substrate 1, forming multiple holes 20 in the epitaxial layer 2 to accommodate a light-color conversion material 4, and growing a light-emitting structure 3 for generating excitation light on the second surface of the growth substrate 1. Then, by filling the holes 20 with the light-color conversion material 4, the excitation light generated by the light-emitting structure 3 is converted from a first light color to a second light color for emission. This method is applicable to fabricating complex light-emitting chips using existing technologies, such as flip-chip red LEDs, using a light-emitting structure with a simple fabrication process, thereby simplifying the fabrication process and saving manufacturing costs. Furthermore, this invention grows the epitaxial layer 2 and the light-emitting structure 3 on two opposite surfaces of the growth substrate 1, eliminating the need for additional steps to fix the light-color conversion material layer and the light-emitting surface of the light-emitting structure 3, thus reducing process steps. Compared to existing technologies that fix the light-color conversion material layer to the light-emitting surface of a blue LED using adhesive methods, this method avoids the problem of adhesive hindering cutting during dicing.

[0058] The above-disclosed examples are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are within the scope of the present invention.

Claims

1. A method for manufacturing a light-emitting chip, characterized in that, include: An epitaxial layer is grown on the first surface of the growth substrate; A light-emitting structure is grown on the second side of the growth substrate, the light-emitting structure being used to generate excitation light, the second side being opposite to the first side; Multiple pores are formed in the epitaxial layer, and the pores are used to accommodate light-color conversion material; The holes are filled with a light-color conversion material, which is used to convert the excitation light from a first light color to a second light color for emission. The growth substrate is a sapphire substrate, and the epitaxial layer is a GaN epitaxial layer; If the light-emitting structure is first grown on the second surface of the growth substrate, and then the plurality of holes are formed on the epitaxial layer, then before the plurality of holes are formed on the epitaxial layer, the process further includes: A protective material is applied to the light-emitting structure to prevent corrosion. After filling the holes with light-color conversion material, the process further includes: A filter structure is covered on the epitaxial layer. The filter structure covers the area of ​​the light-emitting side of the epitaxial layer except for the area corresponding to the hole. The filter structure prevents the light of the first color from passing through.

2. The method for manufacturing a light-emitting chip as described in claim 1, characterized in that, The material of the epitaxial layer is different from the material of the growth substrate, and the structural layer in contact with the second surface of the light-emitting structure and the growth substrate is made of the same material as the epitaxial layer.

3. The method for manufacturing a light-emitting chip as described in any one of claims 1 to 2, characterized in that, The process of growing an epitaxial layer on the first surface of the growth substrate includes: A rough epitaxial layer is grown on the substrate using hydride vapor phase epitaxy at a temperature of 880-980℃, a ratio of Group V to Group III elements of 10-50, and a high pressure of 400-650 torr; or, In a temperature environment of 1000-1050℃, with a ratio of group V elements to group III elements greater than 50, and a low pressure environment of 100-350 torr, and with dopant introduced, a flat n-type or p-type doped epitaxial layer is grown on the growth substrate using hydride vapor phase epitaxy.

4. The method for manufacturing a light-emitting chip as described in any one of claims 1 to 2, characterized in that, After one of the epitaxial layer and the light-emitting structure is grown on the growth substrate, the thickness of the growth substrate is reduced, and then the other of the epitaxial layer and the light-emitting structure is grown on the growth substrate.

5. The method for manufacturing a light-emitting chip as described in claim 1, characterized in that, The epitaxial layer includes multiple sub-epithelial layers; The sub-epitaxial layer includes a growth end and an extension end opposite to each other, the growth end being disposed in contact with the growth substrate, and the extension end being disposed away from the growth substrate; Multiple sub-epieptaxial layers are grown at intervals on the first surface of the growth substrate.

6. The method for manufacturing a light-emitting chip as described in claim 1, characterized in that, After filling the holes with a light-color conversion material, the method further includes: A protective structure is covered on the light-color conversion material to prevent water vapor and oxygen from contacting the light-color conversion material.

7. A light-emitting chip, characterized in that, The light-emitting chip is manufactured using the light-emitting chip manufacturing method as described in any one of claims 1-6.

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