WO2023000632A1

WO2023000632A1 - Laser-assisted in-situ mass transfer method and system

Info

Publication number: WO2023000632A1
Application number: PCT/CN2022/072563
Authority: WO
Inventors: 张震; 杨伟; 刘义杰
Original assignee: 清华大学
Priority date: 2021-07-20
Filing date: 2022-01-18
Publication date: 2023-01-26
Also published as: CN113399822A; CN113399822B

Abstract

The present application discloses a laser-assisted in-situ mass transfer method and system, mainly comprising the following content: using the characteristics of a long infrared laser wavelength and a large laser light spot radius while ensuring the laser energy density to scan, by means of a laser galvanometer, a GaN/sapphire substrate on which Micro-LED chips are grown, and lifting off the Micro-LED chips from the substrate and transferring the Micro-LED chips to a temporary transfer structure; using the "cold processing" effect of an ultrashort pulse laser and the energy accumulation principle of the multi-pulse effect to perform point-by-point fast scanning on the temporary transfer structure by using the laser galvanometer to achieve the high-speed fixed-point mass transfer of the Micro-LED chips to a target substrate; and using a semi-transparent mirror to introduce two laser lights into a same laser processing light path, and providing a laser beam expanding device at an unused laser light outlet. In the present application, the mass transfer of Micro-LED chips is performed by using dual-laser beam scanning and pulse laser point-by-point scanning, so that the transfer rate is high and the yield rate is guaranteed.

Description

A laser-assisted in-situ mass transfer method and system

technical field

The application belongs to the field of semiconductor optoelectronic technology, and in particular relates to a laser-assisted in-situ mass transfer method and system.

Background technique

Micro-LED is a micro-light-emitting diode, which refers to a high-density integrated LED array, in which the distance between LED pixels in the array is on the order of 10 μm, and each LED pixel can emit light by itself. Compared with LCD and OLED technologies, Micro-LED has become a recognized next-generation display technology in the industry due to its high resolution, low power consumption, high brightness, high color saturation, fast response, thin thickness, and long life.

The Micro-LED manufacturing process mainly includes four key technologies, namely epitaxy and chip technology, mass transfer technology, bonding technology, and colorization scheme. Among them, the mass transfer technology mainly refers to the technology of quickly and accurately transferring the Micro-LED array grown on the epitaxial substrate to the driving circuit substrate, and forming a good electrical connection and mechanical fixation with the driving circuit. However, due to the large number of Micro-LED chips that need to be transferred, and the need for fast and accurate transfer, the traditional transfer solution has the problems of long time consumption and insufficient accuracy. Therefore, a time-efficient and high-accuracy method is required Mass transfer method.

The existing mass transfer methods mainly include elastic stamp method, laser-assisted transfer method, electrostatic transfer method, electromagnetic transfer method and fluid self-assembly method. Among them, the transfer yield of the elastic impression method can reach 99.99% at present, but because the transfer amount per hour can only reach 1.0 to 2.5×10 ⁴ units, the transfer area is small and transfer errors are prone to occur due to the deformation of the stamp. ; The electrostatic transfer method is easy to cause damage to the LED chip due to its high voltage, and the electromagnetic transfer method requires an additional ferromagnetic layer; the laser-assisted transfer method can transfer up to 1×10 ⁸ per hour under a small transfer error unit body, but its transfer yield can only reach 90%.

Therefore, how to provide a solution to the above technical problems is a problem that those skilled in the art need to solve.

Contents of the invention

In order to solve the problems of yield and efficiency in the existing mass transfer link, the present application provides a laser-assisted in-situ mass transfer method and system.

The present application provides a laser-assisted in-situ mass transfer method, which comprises the following steps:

S1. Prepare a substrate with Micro-LED chips grown in situ, a temporary transfer structure, a target substrate, a laser galvanometer system, a laser, and a motion table. The temporary transfer structure includes a transparent substrate, a heat-sensitive layer, and an adhesive layer;

S2. Bond the Micro-LED chip grown on the substrate in situ on the adhesive layer of the temporary transfer structure, and use the laser galvanometer system to act on the infrared laser in a continuous scanning manner. on the GaN/sapphire interface of the substrate, so that the GaN near the interface absorbs laser energy and is decomposed, so that the Micro-LED chip is peeled off from the substrate;

S3. Place the temporary transfer structure with the Micro-LED chip bonded directly above the target substrate, and use the motion table to ensure that the position where the Micro-LED chip needs to be placed on the target substrate is consistent with the temporary transfer Structural alignment of Micro-LED chips to be transferred;

S4. After the pulsed laser beam passes through the laser galvanometer system, it directly acts on the position of the Micro-LED chip to be transferred on the temporary transfer structure, and adopts a point-by-point laser scanning method, that is, on the temporary transfer structure Each position of the Micro-LED chip to be transferred uses the pulsed laser to continuously apply multiple pulses, and uses the principle of laser energy accumulation to make the laser energy act on the interface between the transparent substrate and the thermal layer, so that the Micro-LED chip can be selected positively fall onto the target substrate.

Further, in step S1, the heat-sensitive layer material in the temporary transfer structure is polyimide.

Further, in step S2, the substrate bonded with the temporary transfer structure is placed directly under the laser galvanometer system, and the Micro-LED chip surface in the temporary transfer structure is located in the laser galvanometer system The laser scans the back side of the surface so that the scanning range of the laser galvanometer system can act on the GaN/sapphire interface of the substrate to the maximum extent.

Further, in step S3, the distance between the temporary transfer structure on which the Micro-LED chip is bonded and the target substrate is d≈1.2h, where h is the maximum thickness of the placed Micro-LED chip.

Further, in step S4, according to the size of the Micro-LED, use

To determine the focal length required by the applied laser galvanometer system; where r is the maximum distance from the center of the Micro-LED chip to the edge, λ is the laser wavelength, and f is the focal length of the laser galvanometer.

Further, in step S4, the laser vibrating mirror system stays at one Micro-LED chip transfer position for several pulses and then directly transfers to the next Micro-LED chip transfer position, during which the laser light does not need to be switched on and off.

S1. Prepare a substrate with Micro-LED chips grown in situ, a temporary transfer structure, and a target substrate, where the temporary transfer structure includes a substrate, a heat-sensitive layer, and an adhesive layer;

S2. Bond the Micro-LED chip grown on the substrate in situ to the adhesive layer of the temporary transfer structure, and apply laser light to the interface of the substrate in a continuous scanning manner, so that The Micro-LED chip is peeled off from the substrate;

S3. Place the temporary transfer structure with the Micro-LED chip bonded directly above the target substrate, ensuring that the position where the Micro-LED chip needs to be placed on the target substrate is consistent with the position to be transferred on the temporary transfer structure Micro-LED chip position alignment;

S4. Adopt a point-by-point scanning laser scanning method, that is, use a pulsed laser to continuously act on multiple pulses at each position of the Micro-LED chip to be transferred on the temporary transfer structure, and use the principle of laser energy accumulation to make the laser act on the transparent substrate At the interface with the heat-sensitive layer, the Micro-LED chips are selectively dropped onto the target substrate.

Correspondingly, the present application also provides a laser-assisted in-situ mass transfer system, which is characterized in that it includes an infrared laser, an ultrashort pulse laser, an optical gate, a half-mirror system, a laser beam expander, a laser galvanometer system, a temporary Transfer structure, target substrate, motion stage;

Further, the ultrashort pulse laser emits laser with a pulse width less than or equal to 10 ps.

Further, the temporary transfer structure includes a transparent substrate, a heat-sensitive layer and an adhesive layer; grooves for receiving Micro-LED chips are provided on the target substrate.

Further, the motion table is an xyz three-dimensional precision motion table.

Further, the moving table is used to adjust the relative positional relationship between the target substrate and the temporary transfer structure, so that the micro-LED chip groove to be transferred on the target substrate is aligned with the micro-LED chip to be transferred.

Further, the half mirror system includes two light inlets and two light outlets perpendicular to each other, and the two light inlets are aligned with the infrared laser and the ultrashort pulse laser, so that the emitted laser light can be directly transmitted to the half-mirror system; optical gates are respectively arranged between the two light inlets of the half-mirror system and the infrared laser and the ultrashort pulse laser; one of the light-out of the half-mirror system The mouth is aligned with the laser galvanometer, so that the laser beam is applied to the mass transfer of Micro-LED chips, and a beam expander is installed at the other light outlet to expand the beam of the generated beam splitting laser so that its energy density reduce, prevent danger, and ensure the application safety of the device; the temporary transfer structure is installed above the target substrate, and the target substrate is installed on the moving platform.

The beneficial effects of this application are: this application uses parallel processing of infrared lasers and ultrashort pulse lasers at the same time, wherein the use of long-wavelength infrared lasers can expand the laser spot scanning area while ensuring the efficiency of laser energy transmission, effectively improving Separation efficiency of Micro-LED chips; positioning transfer of Micro-LED chips by using ultra-short pulse laser, in which, the "cold processing" effect of ultra-short pulse laser processing can effectively protect the unprocessed area of the temporary transfer structure and greatly avoid Contamination of Micro-LED chips; positioning transfer of Micro-LED chips using ultra-short pulse lasers, in which the Micro-LED chips are selectively transferred to the target by using the energy accumulation effect of multi-pulse processing of ultra-short pulse laser processing Since the pulse width of the ultrashort pulse laser is only on the order of picoseconds or even femtoseconds, and the number of laser pulses required for the accumulation of multi-pulse laser action energy is small, this method is used to process the huge amount of Micro-LED chips. The transfer can greatly increase the transfer efficiency on the basis of effectively improving the processing yield; using the laser galvanometer system to position and move the laser beam can better meet the required processing accuracy and the required laser beam moving speed, and better Realize high-efficiency mass transfer of Micro-LED chips; For the dual-laser coaxial processing system, the half-mirror system is used to convert the two laser beams, which can satisfy the use of the same laser processing optical path for the use of dual beams, and avoid The optical path adjustment is difficult due to the change of the optical path; for the extra laser component generated in the dual-laser coaxial processing system, the laser beam expansion system is added to keep its energy density at a low level and ensure the processing process. Safety.

Description of drawings

The application will be further described below in conjunction with the accompanying drawings and embodiments, in the accompanying drawings:

FIG. 1 is a schematic structural diagram of an embodiment of a laser-assisted in-situ mass transfer system of the present application;

Figures 2 to 3 are schematic diagrams of the process of transferring the Micro-LED chip on the substrate to the temporary transfer structure by using infrared laser;

4 to 6 are schematic diagrams of the process of transferring a Micro-LED chip to a target substrate by using an ultrashort pulse laser.

In the figure: 1-infrared laser; 2-ultrashort pulse laser; 3, 4-optical gate; 5-half mirror system; 6-laser beam expander; 7-laser galvanometer system; 8-temporary transfer structure; 9 -target substrate; 10-micro-adjustment motion table; 11-substrate with in-situ growth of Micro-LED chip; 801-adhesive layer; 802-thermal layer; 803-transparent substrate; 1101-sapphire substrate; 1102-GaN layer; 1103 - Micro-LED chips.

detailed description

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of this application, but not all of them. It should be understood that the specific embodiments described here are only used to explain the present application, not to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

As shown in Figures 1-6, a laser-assisted in-situ mass transfer method includes the following steps:

S1. Prepare the substrate 11 on which the Micro-LED chip 1103 is grown in situ, the temporary transfer structure 8, the target substrate 9, the laser galvanometer system 7, the

lasers

1, 2 and the moving table 10, the temporary transfer structure 8 includes a transparent substrate 801, heat sensitive layer 802 and adhesive layer 803;

S2. Bond the Micro-LED chip 1103 grown in-situ on the substrate 11 on the adhesive layer 803 of the temporary transfer structure 8, by using the laser vibrating mirror system 7 to adopt continuous scanning In this way, the infrared laser is applied to the GaN/sapphire interface of the substrate, so that the GaN near the interface absorbs the laser energy and is decomposed, so that the Micro-LED chip 1103 is peeled off from the substrate 11;

S3. Place the temporary transfer structure 8 bonded with the Micro-LED chip 1103 directly above the target substrate 9, and use the moving table 10 to ensure that the Micro-LED chip 1103 needs to be placed on the target substrate 9. The position is aligned with the Micro-LED chip 1103 to be transferred on the temporary transfer structure 8;

S4. After the pulsed laser beam passes through the laser galvanometer system 7, it directly acts on the position of the Micro-LED chip 1103 to be transferred on the temporary transfer structure 8, and adopts a point-by-point scanning laser scanning method, that is, in the temporary Each position of the Micro-LED chip to be transferred on the transfer structure uses a pulsed laser to continuously act on multiple pulses, and uses the principle of laser energy accumulation to make the laser act on the interface between the transparent substrate 801 and the heat-sensitive layer 802, so that the Micro-LED Chips 1103 are selectively dropped onto the target substrate 9 .

In a preferred embodiment of the present application, as shown in FIG. 2 and FIG. 3 , in step S1 , the material of the heat-sensitive layer 802 in the temporary transfer structure 8 is polyimide.

In a preferred embodiment of the present application, as shown in FIG. 2 and FIG. 3, in step S2, the substrate 11 bonded with the temporary transfer structure 8 is placed directly under the laser galvanometer system 7, and the The surface of the Micro-LED chip 1103 in the temporary transfer structure 8 is located on the back of the laser scanning surface in the laser galvanometer system 7, so that the scanning range of the laser galvanometer system can maximize the GaN/sapphire on the substrate interface.

Specifically, as shown in FIG. 2 and FIG. 3, the infrared laser beam rapidly acts on the substrate 11 of the in-situ grown Micro-LED chip through the laser galvanometer system 7, so that the GaN near the interface in the GaN layer 1102 absorbs The thermal energy generated by the laser light is decomposed by heat, so that the Micro-LED chip 1103 is quickly separated from the sapphire substrate 11 , and the Micro-LED chip 1103 is adhered to the temporary transfer structure 8 through the adhesive layer 801 .

In a preferred embodiment of the present application, as shown in FIG. 4, in step S3, the distance d≈1.2h between the temporary transfer structure 8 with the Micro-LED chips 1103 bonded thereto and the target substrate 9, wherein h is the maximum thickness of the placed Micro-LED chip 1103 .

In the preferred embodiment of the present application, as shown in Figure 4 to Figure 6, in step S4, according to the size of the Micro-LED chip 1103, use

To determine the focal length required by the laser galvanometer system 7 applied; where, r is the maximum distance from the center position of the Micro-LED chip 1103 to the edge, λ is the laser wavelength, and f is the laser galvanometer system 7 focal length.

In a preferred embodiment of the present application, as shown in Fig. 4 to Fig. 6, in step S4, the laser galvanometer system 7 stays in a Micro-LED chip transfer position for multiple pulses and then directly transfers to the next Micro-LED The position of the chip is transferred without changing the on-off of the laser.

Specifically, as shown in FIGS. 4 to 6, the ultrashort pulse laser emitted by the ultrashort pulse laser 2 passes through the laser galvanometer system 7 and then focuses on the interface between the transparent substrate 801 and the heat-sensitive layer 802 of the temporary transfer structure 8 to be transferred. At the position of Micro-LED chip 1103, through the control of the laser galvanometer system 7, the ultrashort pulse laser is continuously applied to multiple pulses at this position. Since the energy of the laser pulses used is low, only when multiple laser pulses act together The thermal effect generated by the energy accumulation effect generated at this position causes air bubbles to be generated between the heat-sensitive layer 802 and the transparent substrate 803 in the temporary transfer structure 8, and the Micro-LED chip 1103 is transferred to the target position in the target substrate 9; When multiple laser pulses act continuously so that the Micro-LED chip 1103 completes the transfer from the temporary transfer structure 8 to the target substrate 9, the action position of the ultrashort pulse laser beam starts to move to the next Micro-LED chip by controlling the laser galvanometer system. At the point where the LED chip is to be transferred, during the movement of the laser beam, due to the interaction between a single laser beam and the thermal layer 802, and the low energy of the set ultrafast laser beam, it is not enough to make it react on the thermal layer 802 Bubbles are produced between the transparent substrate 803, thus ensuring the yield rate during the Micro-LED chip transfer process; when transferring to the next Micro-LED chip to be transferred, the laser vibrating mirror system 7 is used to make the ultrashort pulse laser Multiple pulses are applied continuously here, and the micro-LED chip transfer at this position is completed by using the aforementioned energy accumulation principle.

Correspondingly, the present application also provides a laser-assisted in-situ mass transfer system, as shown in Figure 1, including an infrared laser 1; an ultrashort pulse laser 2;

optical gates

3 and 4; a half-mirror system 5; mirror 6; laser galvanometer system 7; temporary transfer structure 8; target substrate 9; The short-pulse laser light is transmitted through the shutter 4 to the half-mirror system 5 .

In a preferred embodiment of the present application, the ultrashort pulse laser emits laser with a pulse width less than or equal to 10 ps.

In a preferred embodiment of the present application, as shown in FIG. 1 , the temporary transfer structure 8 includes a transparent substrate 801, a heat-sensitive layer 802 and an adhesive layer 803; groove.

In a preferred embodiment of the present application, as shown in FIG. 1 , the motion table 10 is an xyz three-dimensional precision motion table.

In a preferred embodiment of the present application, as shown in FIG. 1, the moving table 10 is used to adjust the relative positional relationship between the target substrate 9 and the temporary transfer structure 8, so that the The groove of the micro-LED chip to be transferred is aligned with the micro-LED chip 1103 to be transferred.

In a preferred embodiment of the present application, as shown in FIG. 1 , the half mirror system 5 includes two light inlets and two light outlets perpendicular to each other, and the two light inlets are aligned with the infrared laser 1 and the ultrashort pulse laser 2, so that the emitted laser light can be directly transmitted to the half mirror system 5 after passing through the respective

optical gates

3 and 4; one of the light outlets is aligned with the laser galvanometer system 7, so that the laser beam Applied to the mass transfer of Micro-LED chips 1103, a laser beam expander 6 is installed at the other light outlet, and the beam splitting laser generated is expanded by using the principle of expanding the laser beam diameter and reducing its laser energy density, so that Its energy density is reduced, which prevents danger and ensures the application safety of the device.

This application has the following advantages:

1. This application adopts the parallel processing method of using infrared laser and ultrashort pulse laser at the same time, in which the use of long-wavelength infrared laser can expand the scanning area of laser spot while ensuring the efficiency of laser energy transmission, and effectively improve the separation of Micro-LED chips efficiency;

2. Utilize ultrashort pulse laser for positioning transfer of Micro-LED chips. Among them, the "cold processing" effect of ultrashort pulse laser processing can effectively protect the unprocessed area of the temporary transfer structure and greatly avoid damage to the Micro-LED chip. pollute;

3. Utilize ultrashort pulse laser for positioning transfer of Micro-LED chips, in which, the energy accumulation effect of multi-pulse processing of ultrashort pulse laser is used to selectively transfer Micro-LED chips to the target substrate, due to the ultrashort pulse The pulse width of the laser is only on the order of picoseconds or even femtoseconds, and the number of laser pulses required for the accumulation of multi-pulse laser energy is small. Therefore, using this method to transfer a large amount of Micro-LED chips can effectively improve the processing On the basis of yield rate, the transfer efficiency is greatly increased;

4. Using the laser galvanometer system to position and move the laser beam can better meet the required processing accuracy and the required moving speed of the laser beam, and better realize the high-efficiency mass transfer of Micro-LED chips;

5. For the dual-laser coaxial processing system, the half-mirror system is used to convert the two laser beams, which can satisfy the use of the same laser processing optical path for the use of dual beams, and avoid the difficulty of optical path adjustment caused by the change of the optical path;

6. For the extra laser component generated in the dual laser coaxial processing system, the laser beam expansion system is added to keep its energy density at a low level and ensure the safety during processing.

In the description of this application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientation or positional relationship indicated by "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and The description is simplified, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus should not be construed as limiting the application. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations. In addition, in the description of the present application, unless otherwise specified, "plurality" means two or more.

It should be understood that those skilled in the art may make improvements or transformations based on the above description, and all such improvements and transformations shall fall within the protection scope of the appended claims of the present application.

Claims

A laser-assisted in-situ mass transfer method, characterized in that it comprises the following steps:

S1. Prepare a substrate with Micro-LED chips grown in situ, a temporary transfer structure, a target substrate, a laser galvanometer system, a laser, and a motion table. The temporary transfer structure includes a transparent substrate, a heat-sensitive layer, and an adhesive layer;

S2. Bond the Micro-LED chip grown on the substrate in situ on the adhesive layer of the temporary transfer structure, and use the laser galvanometer system to act on the infrared laser in a continuous scanning manner. on the GaN/sapphire interface of the substrate, so that the GaN near the interface absorbs laser energy and is decomposed, so that the Micro-LED chip is peeled off from the substrate;

S3. Place the temporary transfer structure with the Micro-LED chip bonded directly above the target substrate, and use the motion table to ensure that the position where the Micro-LED chip needs to be placed on the target substrate is consistent with the temporary transfer Structural alignment of Micro-LED chips to be transferred;

S4. After the pulsed laser beam passes through the laser galvanometer system, it directly acts on the position of the Micro-LED chip to be transferred on the temporary transfer structure, and adopts a point-by-point laser scanning method, that is, on the temporary transfer structure Each position of the Micro-LED chip to be transferred uses a pulsed laser to continuously act on multiple pulses, and uses the principle of laser energy accumulation to make the laser act on the interface between the transparent substrate and the heat-sensitive layer, so that the Micro-LED chip can be selectively placed. into the target substrate.
A laser-assisted in-situ mass transfer method according to claim 1, characterized in that, in step S1, the heat-sensitive layer material in the temporary transfer structure is polyimide.
A laser-assisted in-situ mass transfer method according to claim 1, wherein in step S2, the substrate bonded with the temporary transfer structure is placed directly under the laser galvanometer system, so that The surface of the Micro-LED chip in the temporary transfer structure is located on the back of the laser scanning surface in the laser vibrating mirror system, so that the scanning range of the laser vibrating mirror can act on the GaN/sapphire interface of the substrate to the greatest extent.
The laser-assisted in-situ mass transfer method according to claim 1, wherein in step S3, the distance d≈ 1.2h, where h is the maximum thickness of the placed Micro-LED chip.
A laser-assisted in-situ mass transfer method according to claim 1, characterized in that in step S4, according to the size of the Micro-LED, use
To determine the focal length required by the applied laser galvanometer system; where r is the maximum distance from the center of the Micro-LED chip to the edge, λ is the laser wavelength, and f is the focal length of the laser galvanometer.
A laser-assisted in-situ mass transfer method according to claim 1, characterized in that in step S4, the laser vibrating mirror system stays in a Micro-LED chip transfer position for multiple pulses and then directly transfers to the next The position of the Micro-LED chip is transferred, and there is no need to change the laser on and off during the process.
A laser-assisted in-situ mass transfer method, characterized in that it comprises the following steps:

S1. Prepare a substrate with Micro-LED chips grown in situ, a temporary transfer structure, and a target substrate, where the temporary transfer structure includes a substrate, a heat-sensitive layer, and an adhesive layer;

S2. Bond the Micro-LED chip grown on the substrate in situ to the adhesive layer of the temporary transfer structure, and apply laser light to the interface of the substrate in a continuous scanning manner, so that The Micro-LED chip is peeled off from the substrate;

S3. Place the temporary transfer structure with the Micro-LED chip bonded directly above the target substrate, ensuring that the position where the Micro-LED chip needs to be placed on the target substrate is consistent with the position to be transferred on the temporary transfer structure Micro-LED chip position alignment;

S4. Adopt a point-by-point scanning laser scanning method, that is, use a pulsed laser to continuously act on multiple pulses at each position of the Micro-LED chip to be transferred on the temporary transfer structure, and use the principle of laser energy accumulation to make the laser act on the transparent substrate At the interface with the heat-sensitive layer, the Micro-LED chips are selectively dropped onto the target substrate.
A laser-assisted in-situ mass transfer system, characterized in that it includes an infrared laser, an ultrashort pulse laser, an optical gate, a half-reflecting mirror system, a laser beam expander, a laser galvanometer system, a temporary transfer structure, a target substrate, and a moving tower.
The laser-assisted in-situ mass transfer system according to claim 8, characterized in that the ultrashort pulse laser emits laser with a pulse width less than or equal to 10 picoseconds.
A laser-assisted in-situ mass transfer system according to claim 8, wherein the temporary transfer structure includes a transparent substrate, a heat-sensitive layer and an adhesive layer; Grooves for LED chips.
The laser-assisted in-situ mass transfer system according to claim 8, wherein the moving stage is used to adjust the relative positional relationship between the target substrate and the temporary transfer structure, so that the target The micro-LED chip groove to be transferred on the substrate is aligned with the micro-LED chip to be transferred.
The laser-assisted in-situ mass transfer system according to claim 8, characterized in that the motion table is an xyz three-dimensional precision motion table.
A laser-assisted in-situ mass transfer system according to claim 8, wherein the half-mirror system includes two light inlets and two light outlets perpendicular to each other, and the two light inlets are aligned between the infrared laser and the ultrashort pulse laser, so that the emitted laser light can be directly transmitted to the half mirror system; the two light inlets of the half mirror system are connected to the infrared laser and the ultrashort pulse laser Optical shutters are respectively arranged between them; one of the light outlets of the half-mirror system is aligned with the laser scanning galvanometer, so that the laser beam is applied to the mass transfer of Micro-LED chips, and an expander is set at the other light outlet. The beam mirror expands the beam of the generated beam splitting laser so as to reduce its energy density, prevent danger, and ensure the application safety of the device; the temporary transfer structure is installed above the target substrate, and the target substrate is installed on the exercise platform.