CN113471339B - Mass transfer method of Micro-LED chips - Google Patents
Mass transfer method of Micro-LED chips Download PDFInfo
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- CN113471339B CN113471339B CN202111025739.4A CN202111025739A CN113471339B CN 113471339 B CN113471339 B CN 113471339B CN 202111025739 A CN202111025739 A CN 202111025739A CN 113471339 B CN113471339 B CN 113471339B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0095—Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
- H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
- H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
- H01L2221/68368—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
- H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
- H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
- H01L2221/68381—Details of chemical or physical process used for separating the auxiliary support from a device or wafer
- H01L2221/68386—Separation by peeling
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Abstract
The invention relates to a mass transfer method of Micro-LED chips. The first side face and the second side face of each Micro-LED chip are respectively provided with a plurality of first auxiliary portions and a plurality of second auxiliary portions, the first auxiliary portions and the second auxiliary portions are located in the peripheral auxiliary area, the non-active functional surface of the functional core area of each Micro-LED chip is etched to form a plurality of mutually separated first grooves, the contact area between the second bonding layer on the second transient substrate and the Micro-LED chip can be increased, the stability of the Micro-LED chip in the transfer process can be improved, and the first auxiliary portions and the second auxiliary portions are formed outside the functional core area instead of completely reserving the peripheral auxiliary area, so that the first auxiliary portions and the second auxiliary portions are removed after the transfer is completed. The transfer method can ensure the precision and yield of mass transfer.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a massive transfer method of Micro-LED chips.
Background
The display principle of the Micro-LED display is that after the traditional LED chip structure design is subjected to thinning, microminiaturization and arraying, the size of the formed Micro-LED chip is only about 1-10 mu m grade; then transferring the Micro-LED chips to a drive circuit substrate manufactured by adopting PCB, flexible PCB, CMOS/TFT integrated circuit technology and the like in batch mode, then completing the preparation of a protective layer and an upper electrode by utilizing physical vapor deposition and/or chemical vapor deposition technology, and finally packaging the upper substrate to obtain the Micro-LED display. Compared with the existing LCD display and OLED display, the Micro-LED display has advantages in brightness, luminous efficiency, contrast, energy consumption, reaction time, visual angle, resolution, service life and other indexes. Because the Micro-LED chips are too small and huge in quantity, how to transfer the Micro-LED chips in a huge manner is a core technical problem in the current Micro-LED industrialization process.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a mass transfer method of Micro-LED chips.
In order to achieve the above object, the present invention provides a bulk transfer method for Micro-LED chips, comprising the following steps:
step (1): providing a first semiconductor wafer, wherein the first semiconductor wafer comprises a plurality of Micro-LED chips arranged in a matrix, each Micro-LED chip is provided with a functional core area and a peripheral auxiliary area, and the peripheral auxiliary area surrounds the functional core area.
Step (2): providing a first temporary substrate, disposing a first adhesive layer on the first temporary substrate, and further disposing the first semiconductor wafer on the first adhesive layer with an active functional surface of the functional core area facing the first adhesive layer.
And (3): and then, etching the first semiconductor wafer to form a plurality of first auxiliary parts on a first side surface of each Micro-LED chip and a plurality of second auxiliary parts on a second side surface opposite to the first side surface, wherein the plurality of first auxiliary parts and the plurality of second auxiliary parts are all positioned in the peripheral auxiliary area, and the plurality of first auxiliary parts and the plurality of second auxiliary parts are respectively in one-to-one correspondence.
And (4): and then etching the non-active functional surface of the functional core area of each Micro-LED chip to form a plurality of first grooves separated from each other.
And (5): and then, cutting the first semiconductor wafer to form a plurality of discrete Micro-LED chips, wherein each Micro-LED chip is provided with a plurality of first auxiliary parts and a plurality of second auxiliary parts which are arranged oppositely, a first gap is formed between every two adjacent first auxiliary parts, and a second gap is formed between every two adjacent second auxiliary parts.
And (6): then, a second transient substrate is provided, a second bonding layer is arranged on the second transient substrate, the Micro-LED chips in the first semiconductor wafer are bonded to the second transient substrate through the second bonding layer, the second bonding layer is bonded with the first auxiliary parts and the second auxiliary parts of each Micro-LED chip, and a part of the second bonding layer is embedded into the first groove.
And (7): and then providing a target substrate, wherein a plurality of Micro-LED chip mounting areas are arranged on the target substrate, and then a first bulge corresponding to the first gap and a second bulge corresponding to the second gap are arranged on each Micro-LED chip mounting area.
And (8) selectively transferring the Micro-LED chips on the second transient substrate to the target substrate, wherein in the selective transfer process, the first and second protrusions are respectively embedded into the first and second gaps, so that the selectively transferred Micro-LED chips are separated from the second transient substrate.
And (9) cutting the transferred Micro-LED chip to completely remove the first auxiliary parts and the second auxiliary parts on the first side surface and the second side surface of the Micro-LED chip, and then flattening the transferred Micro-LED chip to eliminate the first groove and enable the inactive functional surface of the Micro-LED chip to be a flat surface.
As a preferred technical solution, in the step (1), each Micro-LED chip includes a substrate, and an N-type gallium nitride layer, a quantum well light-emitting layer, and a P-type gallium nitride layer disposed on the substrate.
As a preferable mode, in the step (1), the functional core region includes the substrate, the N-type gallium nitride layer, the quantum well light-emitting layer, and the P-type gallium nitride layer, and the peripheral auxiliary region includes only the substrate.
Preferably, in the step (3), a plurality of third auxiliary portions and a plurality of fourth auxiliary portions are formed on a third side surface and a fourth side surface adjacent to the first side surface of each Micro-LED chip, respectively, while the plurality of first and second auxiliary portions are formed.
Preferably, in the step (4), the plurality of first grooves are provided in the substrate and do not penetrate through the substrate.
Preferably, the first adhesive layer and the second adhesive layer are temporary adhesive layers, and the first and second temporary substrates are transparent substrates.
As a preferred technical scheme, when the color of the Micro-LED chip on the first semiconductor wafer is red, providing a second semiconductor wafer, wherein the color of the Micro-LED chip on the second semiconductor wafer is green, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chip on the second semiconductor wafer to the target substrate; providing a third semiconductor wafer, wherein the color of the Micro-LED chips on the third semiconductor wafer is blue, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the third semiconductor wafer to the target substrate.
The invention has the beneficial effects that:
in the mass transfer method of the Micro-LED chips, a plurality of first auxiliary parts are formed on a first side surface of each Micro-LED chip, a plurality of second auxiliary parts are formed on a second side surface opposite to the first side surface, the first auxiliary parts and the second auxiliary parts are all positioned in the peripheral auxiliary area, the first auxiliary parts and the second auxiliary parts are respectively in one-to-one correspondence, the inactive functional surface of the functional core area of each Micro-LED chip is etched to form a plurality of first grooves which are separated from each other, so that the contact area between the second adhesive layer on the second transient substrate and the Micro-LED chips can be increased, the stability of the Micro-LED chips in the transfer process can be improved, and the first auxiliary parts and the second auxiliary parts are formed outside the functional core area, instead of completely reserving the peripheral auxiliary area, it is convenient to remove the first and second auxiliary portions after the transfer is completed. Furthermore, by further arranging the third auxiliary part and the fourth auxiliary part, the Micro-LED chip can be further effectively prevented from falling off from the second transient substrate in the transfer process, and the precision and yield of mass transfer can be further ensured.
And then, cutting the transferred Micro-LED chip to completely remove the first auxiliary part and the second auxiliary part on the first side surface and the second side surface of the Micro-LED chip, and when a third auxiliary part and a fourth auxiliary part are arranged, simultaneously removing the third auxiliary part and the fourth auxiliary part in the cutting treatment.
Drawings
FIG. 1 is a schematic view of a semiconductor wafer according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a semiconductor wafer disposed on a first transient substrate according to an embodiment of the invention.
Fig. 3 is a schematic structural diagram illustrating a plurality of first and second auxiliary portions respectively formed on the first and second side surfaces of each Micro-LED chip according to an embodiment of the present invention.
Fig. 4 is a schematic structural diagram illustrating a plurality of first grooves separated from each other formed on the non-active functional surface of the functional core region of each of the Micro-LED chips according to an embodiment of the present invention.
FIG. 5 is a schematic structural diagram of a single Micro-LED chip according to an embodiment of the present invention.
Fig. 6 is a schematic structural diagram illustrating a plurality of Micro-LED chips disposed on a second temporary substrate according to an embodiment of the invention.
FIG. 7 is a schematic view of a target substrate according to an embodiment of the invention.
FIG. 8 is a schematic structural view illustrating the selective transfer of Micro-LED chips to a target substrate according to an embodiment of the present invention.
FIG. 9 is a schematic structural view illustrating a dicing process performed on the transferred Micro-LED chip according to an embodiment of the present invention.
Description of the reference numerals
A first semiconductor wafer 100; Micro-LED chip 101; a functional core area 102; a peripheral auxiliary area 103; a first transient substrate 104; a first adhesive layer 105; the first auxiliary portion 106; the second auxiliary portion 107; a third auxiliary portion 108; the fourth auxiliary portion 109; a first groove 110; the first gap 111; a second gap 112; a second transient substrate 200; a second adhesive layer 201; a target substrate 300; Micro-LED chip mounting area 301; a first protrusion 302; a second protrusion 303.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
As shown in fig. 1 to 9, the present embodiment provides a bulk transfer method for Micro-LED chips, which includes the following steps:
in a specific embodiment, as shown in fig. 1, in step (1), a first semiconductor wafer 100 is provided, where the first semiconductor wafer 100 includes a plurality of Micro-LED chips 101 arranged in a matrix, each of the Micro-LED chips 101 has a functional core region 102 and a peripheral auxiliary region 103, and the peripheral auxiliary region 103 surrounds the functional core region 102.
In a specific embodiment, each Micro-LED chip 101 includes a substrate, and an N-type gallium nitride layer, a quantum well light emitting layer, and a P-type gallium nitride layer disposed on the substrate.
In a specific embodiment, the Micro-LED chip 101 is a flip chip, that is, a P-type electrode and an N-type electrode are disposed on one side of the Micro-LED chip 101.
In a more preferred embodiment, the functional core region 102 has the substrate, the N-type gallium nitride layer, the quantum well light emitting layer, and the P-type gallium nitride layer, while the peripheral auxiliary region 103 has only the substrate.
More specifically, the substrate may be a silicon substrate, a silicon carbide substrate, a sapphire substrate, or a substrate such as a gallium nitride substrate that is suitable for manufacturing an epitaxial layer in the field, and further, an N-type gallium nitride layer, a quantum well light-emitting layer, and a P-type gallium nitride layer are epitaxially grown on the substrate in sequence to obtain the first semiconductor wafer 100, where the first semiconductor wafer 100 has a plurality of Micro-LED chips 101. Of course, in the present invention, the N-type layer and the P-type layer of the Micro-LED chip 101 may be made of gallium arsenide, silicon carbide, aluminum gallium nitride, or other suitable materials.
In the process of defining the functional core area 102 and the peripheral auxiliary area 103, the N-type gallium nitride layer, the quantum well light emitting layer and the P-type gallium nitride layer in the peripheral auxiliary area 103 can be removed under the coverage of the photoresist patterned mask by a wet etching or dry etching process, only the substrate is retained, and since only the substrate is retained, the stability of the junction between the transient substrate and the Micro-LED chip 101 is not hindered to be increased in the subsequent transfer process, and since the part of the substrate does not contact the target substrate in the subsequent process of removing the auxiliary part, the target substrate is not influenced or damaged by the removing process.
In a specific embodiment, as shown in fig. 2, in step (2), a first temporary substrate 104 is provided, a first adhesion layer 105 is disposed on the first temporary substrate 104, and the first semiconductor wafer 100 is further disposed on the first adhesion layer 105, with the active function of the functional core area 102 facing the first adhesion layer 105.
In a specific embodiment, the first adhesive layer 105 is a temporary adhesive layer, which may lose adhesiveness under heat or light, and thus facilitate adhesion or peeling, and the first transient substrate 104 is a transparent substrate, and more specifically, a tempered glass plate.
In a specific embodiment, as shown in fig. 3, in step (3), etching is performed on the first semiconductor wafer 100 to form a plurality of first auxiliary portions 106 on a first side surface of each Micro-LED chip, and a plurality of second auxiliary portions 107 on a second side surface opposite to the first side surface, where the plurality of first and second auxiliary portions 106 and 107 are located in the peripheral auxiliary region 103, and the plurality of first auxiliary portions 106 and the plurality of second auxiliary portions 107 are respectively in one-to-one correspondence.
In a more preferred embodiment, in the step (3), a plurality of third auxiliary portions 108 and a plurality of fourth auxiliary portions 109 are formed on a third side and a fourth side of each Micro-LED chip adjacent to the first side, while the plurality of first and second auxiliary portions 106 and 107 are formed.
In a specific embodiment, a portion of the substrate in the peripheral auxiliary region 103 is etched through a wet etching process or a dry etching process to form the first, second, third, and fourth auxiliary portions.
In a specific embodiment, as shown in fig. 4, in step (4), the non-active functional surface of the functional core area 102 of each of the Micro-LED chips 101 is etched to form a plurality of first grooves 110 separated from each other.
In a specific embodiment, the first plurality of grooves 110 is disposed in the substrate and does not extend through the substrate.
In a more specific embodiment, a plurality of first grooves 110 are formed in an array by an etching process, and further, the depth of the first grooves 110 is more than half of the thickness of the substrate.
In a specific embodiment, as shown in fig. 5, fig. 5 is a schematic structural diagram of a single Micro-LED chip, in step (5), the first semiconductor wafer 100 is then cut to form a plurality of discrete Micro-LED chips 101, each of the Micro-LED chips 101 has a plurality of first auxiliary portions 106 and a plurality of second auxiliary portions 107 disposed opposite to each other, a first gap 111 is formed between adjacent first auxiliary portions 106, and a second gap 112 is formed between adjacent second auxiliary portions 107.
In a specific embodiment, the discrete Micro-LED chips 101 are formed by a laser cutting process or a knife cutting process.
In a specific embodiment, as shown in fig. 6, in step (6), a second transient substrate 200 is then provided, a second adhesive layer 201 is disposed on the second transient substrate 200, the plurality of Micro-LED chips 101 in the first semiconductor wafer 100 are adhered to the second transient substrate 200 through the second adhesive layer 201, the second adhesive layer 201 adheres the plurality of first and second auxiliary portions 106 and 107 of each Micro-LED chip 101, a portion of the second adhesive layer 201 is embedded in the first groove 110, and then the first transient substrate 104 is removed.
In a specific embodiment, the second adhesive layer 201 is a temporary adhesive layer, and thus may lose adhesiveness under heat or light, and thus facilitate adhesion or peeling, and the second temporary substrate 200 is a transparent substrate, and more specifically, may be a tempered glass plate.
In a specific embodiment, as shown in fig. 7, in step (7), a target substrate 300 is then provided, a plurality of Micro-LED chip mounting areas 301 are disposed on the target substrate 300, and then a first bump 302 corresponding to the first gap 111 and a second bump 303 corresponding to the second gap 112 are disposed on each of the Micro-LED chip mounting areas 301.
In a specific embodiment, the Micro-LED chip mounting area 301 of the target substrate 300 is provided with conductive pads electrically connected to the P-type electrode and the N-type electrode of the Micro-LED chip, respectively.
In a specific embodiment, the first bump 302 and the second bump 303 may be formed by depositing a metal material, specifically, copper, and then forming the first bump 302 and the second bump 303 through a patterning process.
In a specific embodiment, as shown in fig. 8, in step (8), the Micro-LED chips on the second transient substrate 200 are then selectively transferred to the target substrate 300, so that the first and second bumps 302 and 303 are embedded into the first and second gaps 111 and 112, respectively, during the selective transfer process, thereby separating the selectively transferred Micro-LED chips 101 from the second transient substrate 200.
In a specific embodiment, the selective transfer of the Micro-LED chip is accomplished by selectively illuminating the second adhesive layer 201, thereby causing a portion of the second adhesive layer 201 to lose its adhesiveness, and further selectively peeling off the second temporary substrate 200.
In a specific embodiment, the first and second bumps 302 and 303 are embedded in the first and second gaps 111 and 112, respectively, to facilitate positioning of the Micro-LED chip and improve the accuracy of the transfer.
In a specific embodiment, as shown in fig. 9, in step (9), the transferred Micro-LED chip 101 is then subjected to a cutting process to completely remove the first and second auxiliary portions 106 and 107 on the first and second sides of the Micro-LED chip 101, and then the transferred Micro-LED chip is subjected to a planarization process to eliminate the first groove 110, so that the inactive functional surface of the Micro-LED chip 101 is a flat surface.
In a specific embodiment, the first and second auxiliary portions 106 and 107 are removed while the first and second bumps 302 and 303 are removed, thereby further miniaturizing the Micro-LED chip.
In a further embodiment, when the color of the Micro-LED chips on the first semiconductor wafer is red, providing a second semiconductor wafer, and the color of the Micro-LED chips on the second semiconductor wafer is green, repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the second semiconductor wafer to the target substrate; providing a third semiconductor wafer, wherein the color of the Micro-LED chips on the third semiconductor wafer is blue, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the third semiconductor wafer to the target substrate to form the Micro-LED display.
In another preferred embodiment, the present invention provides a bulk transfer method for Micro-LED chips, comprising the following steps:
step (1): providing a first semiconductor wafer, wherein the first semiconductor wafer comprises a plurality of Micro-LED chips arranged in a matrix, each Micro-LED chip is provided with a functional core area and a peripheral auxiliary area, and the peripheral auxiliary area surrounds the functional core area.
Step (2): providing a first temporary substrate, disposing a first adhesive layer on the first temporary substrate, and further disposing the first semiconductor wafer on the first adhesive layer with an active functional surface of the functional core area facing the first adhesive layer.
And (3): and then, etching the first semiconductor wafer to form a plurality of first auxiliary parts on a first side surface of each Micro-LED chip and a plurality of second auxiliary parts on a second side surface opposite to the first side surface, wherein the plurality of first auxiliary parts and the plurality of second auxiliary parts are all positioned in the peripheral auxiliary area, and the plurality of first auxiliary parts and the plurality of second auxiliary parts are respectively in one-to-one correspondence.
And (4): and then etching the non-active functional surface of the functional core area of each Micro-LED chip to form a plurality of first grooves separated from each other.
And (5): and then, cutting the first semiconductor wafer to form a plurality of discrete Micro-LED chips, wherein each Micro-LED chip is provided with a plurality of first auxiliary parts and a plurality of second auxiliary parts which are arranged oppositely, a first gap is formed between every two adjacent first auxiliary parts, and a second gap is formed between every two adjacent second auxiliary parts.
And (6): then, a second transient substrate is provided, a second bonding layer is arranged on the second transient substrate, the Micro-LED chips in the first semiconductor wafer are bonded to the second transient substrate through the second bonding layer, the second bonding layer is bonded with the first auxiliary parts and the second auxiliary parts of each Micro-LED chip, and a part of the second bonding layer is embedded into the first groove.
And (7): and then providing a target substrate, wherein a plurality of Micro-LED chip mounting areas are arranged on the target substrate, and then a first bulge corresponding to the first gap and a second bulge corresponding to the second gap are arranged on each Micro-LED chip mounting area.
And (8) selectively transferring the Micro-LED chips on the second transient substrate to the target substrate, wherein in the selective transfer process, the first and second protrusions are respectively embedded into the first and second gaps, so that the selectively transferred Micro-LED chips are separated from the second transient substrate.
And (9) cutting the transferred Micro-LED chip to completely remove the first auxiliary parts and the second auxiliary parts on the first side surface and the second side surface of the Micro-LED chip, and then flattening the transferred Micro-LED chip to eliminate the first groove and enable the inactive functional surface of the Micro-LED chip to be a flat surface.
In a preferred technical solution, in the step (1), each Micro-LED chip includes a substrate, and an N-type gallium nitride layer, a quantum well light-emitting layer, and a P-type gallium nitride layer disposed on the substrate.
In a preferred embodiment, in the step (1), the functional core region includes the substrate, the N-type gallium nitride layer, the quantum well light-emitting layer, and the P-type gallium nitride layer, and the peripheral auxiliary region includes only the substrate.
In a preferred embodiment, in the step (3), a plurality of third auxiliary portions and a plurality of fourth auxiliary portions are formed on a third side surface and a fourth side surface adjacent to the first side surface of each of the Micro-LED chips, respectively, while the plurality of first and second auxiliary portions are formed.
In a preferred embodiment, in the step (4), the plurality of first grooves are disposed in the substrate and do not penetrate through the substrate.
In a preferred embodiment, the first adhesive layer and the second adhesive layer are temporary adhesive layers, and the first transient substrate and the second transient substrate are transparent substrates.
In a preferred technical scheme, when the color of the Micro-LED chip on the first semiconductor wafer is red, providing a second semiconductor wafer, wherein the color of the Micro-LED chip on the second semiconductor wafer is green, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chip on the second semiconductor wafer to the target substrate; providing a third semiconductor wafer, wherein the color of the Micro-LED chips on the third semiconductor wafer is blue, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the third semiconductor wafer to the target substrate.
The invention has the beneficial effects that:
in the mass transfer method of the Micro-LED chips, a plurality of first auxiliary parts are formed on a first side surface of each Micro-LED chip, a plurality of second auxiliary parts are formed on a second side surface opposite to the first side surface, the first auxiliary parts and the second auxiliary parts are all positioned in the peripheral auxiliary area, the first auxiliary parts and the second auxiliary parts are respectively in one-to-one correspondence, the inactive functional surface of the functional core area of each Micro-LED chip is etched to form a plurality of first grooves which are separated from each other, so that the contact area between the second adhesive layer on the second transient substrate and the Micro-LED chips can be increased, the stability of the Micro-LED chips in the transfer process can be improved, and the first auxiliary parts and the second auxiliary parts are formed outside the functional core area, instead of completely reserving the peripheral auxiliary area, it is convenient to remove the first and second auxiliary portions after the transfer is completed. Furthermore, by further arranging the third auxiliary part and the fourth auxiliary part, the Micro-LED chip can be further effectively prevented from falling off from the second transient substrate in the transfer process, and the precision and yield of mass transfer can be further ensured.
And then, cutting the transferred Micro-LED chip to completely remove the first auxiliary part and the second auxiliary part on the first side surface and the second side surface of the Micro-LED chip, and when a third auxiliary part and a fourth auxiliary part are arranged, simultaneously removing the third auxiliary part and the fourth auxiliary part in the cutting treatment.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (7)
1. A mass transfer method of Micro-LED chips is characterized in that: the method comprises the following steps:
step (1): providing a first semiconductor wafer, wherein the first semiconductor wafer comprises a plurality of Micro-LED chips arranged in a matrix, each Micro-LED chip is provided with a functional core area and a peripheral auxiliary area, and the peripheral auxiliary area surrounds the functional core area;
step (2): providing a first temporary substrate, disposing a first adhesive layer on the first temporary substrate, and further disposing the first semiconductor wafer on the first adhesive layer with the active functional surface of the functional core area facing the first adhesive layer;
and (3): etching the first semiconductor wafer to form a plurality of first auxiliary parts on a first side surface of each Micro-LED chip and a plurality of second auxiliary parts on a second side surface opposite to the first side surface, wherein the first auxiliary parts and the second auxiliary parts are located in the peripheral auxiliary area, and the first auxiliary parts and the second auxiliary parts are respectively in one-to-one correspondence;
and (4): etching the non-active functional surface of the functional core area of each Micro-LED chip to form a plurality of mutually separated first grooves;
and (5): cutting the first semiconductor wafer to form a plurality of discrete Micro-LED chips, wherein each Micro-LED chip is provided with a plurality of first auxiliary parts and a plurality of second auxiliary parts which are arranged oppositely, a first gap is formed between every two adjacent first auxiliary parts, and a second gap is formed between every two adjacent second auxiliary parts;
and (6): then providing a second transient substrate, arranging a second bonding layer on the second transient substrate, bonding the plurality of Micro-LED chips in the first semiconductor wafer to the second transient substrate through the second bonding layer, wherein the second bonding layer bonds the plurality of first and second auxiliary parts of each Micro-LED chip and a part of the second bonding layer is embedded into the first groove;
and (7): then, providing a target substrate, wherein a plurality of Micro-LED chip mounting areas are arranged on the target substrate, and then, a first bulge corresponding to the first gap and a second bulge corresponding to the second gap are arranged on each Micro-LED chip mounting area;
step (8) selectively transferring the Micro-LED chips on the second transient substrate to the target substrate, wherein during the selective transfer, the first and second protrusions are respectively embedded into the first and second gaps, thereby separating the selectively transferred Micro-LED chips from the second transient substrate;
and (9) cutting the transferred Micro-LED chip to completely remove the first auxiliary parts and the second auxiliary parts on the first side surface and the second side surface of the Micro-LED chip, and then flattening the transferred Micro-LED chip to eliminate the first groove and enable the inactive functional surface of the Micro-LED chip to be a flat surface.
2. The macro transfer method of Micro-LED chips of claim 1, wherein: in the step (1), each Micro-LED chip includes a substrate, and an N-type gallium nitride layer, a quantum well light-emitting layer, and a P-type gallium nitride layer disposed on the substrate.
3. The macro transfer method of Micro-LED chips of claim 2, wherein: in the step (1), the functional core region has the substrate, the N-type gallium nitride layer, the quantum well light-emitting layer, and the P-type gallium nitride layer, and the peripheral auxiliary region has only the substrate.
4. The macro transfer method of Micro-LED chips of claim 1, wherein: in the step (3), while the first and second pluralities of auxiliary portions are formed, a plurality of third auxiliary portions and a plurality of fourth auxiliary portions are formed on third and fourth sides adjacent to the first side in each of the Micro-LED chips, respectively.
5. The macro transfer method of Micro-LED chips of claim 3, wherein: in the step (4), a plurality of the first grooves are provided in the substrate without penetrating the substrate.
6. The macro transfer method of Micro-LED chips of claim 1, wherein: the first bonding layer and the second bonding layer are temporary bonding layers, and the first transient substrate and the second transient substrate are transparent substrates.
7. The macro transfer method of Micro-LED chips of claim 1, wherein: when the color of the Micro-LED chips on the first semiconductor wafer is red, providing a second semiconductor wafer, wherein the color of the Micro-LED chips on the second semiconductor wafer is green, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the second semiconductor wafer to the target substrate; providing a third semiconductor wafer, wherein the color of the Micro-LED chips on the third semiconductor wafer is blue, and repeating the chip transfer process of the steps (2) to (9) to transfer the Micro-LED chips on the third semiconductor wafer to the target substrate.
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| CN110574174A (en) * | 2016-12-13 | 2019-12-13 | 香港北大青鸟显示有限公司 | Mass transfer of microstructures using adhesives |
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| CN112216627A (en) * | 2019-07-10 | 2021-01-12 | 美科米尚技术有限公司 | Method for transferring micro-components and component transfer system |
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| CN110574174A (en) * | 2016-12-13 | 2019-12-13 | 香港北大青鸟显示有限公司 | Mass transfer of microstructures using adhesives |
| CN112017550A (en) * | 2019-05-31 | 2020-12-01 | 云谷（固安）科技有限公司 | Display panel, manufacturing method thereof and display device |
| CN112216627A (en) * | 2019-07-10 | 2021-01-12 | 美科米尚技术有限公司 | Method for transferring micro-components and component transfer system |
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