Micro-device integration method, micro-device and micro-led array integration method

Abstract

The present disclosure belongs to the technical field of microelectronic packaging and integration, and relates to a micro device integration method, a micro device and a Micro-LED array integration method. The micro device integration method comprises the following steps: preparing a cathode electrode and an anode electrode on a receiving substrate; arranging conductive bumps on the cathode electrode and the anode electrode of the receiving substrate respectively; arranging an electrically insulating separation structure, which prevents the cathode electrode and the anode electrode of the receiving substrate from being electrically connected; transferring the micro device to a target position, and initially bonding the micro device to the receiving substrate, wherein the electrically insulating separation structure prevents the cathode electrode and the anode electrode of the micro device from being electrically connected; and deforming the conductive bumps, so that the conductive bumps are raised after deformation, and the electrodes of the receiving substrate and the micro device are electrically connected. Through cooperation of the electrically insulating separation structure and the conductive bumps, the present disclosure reduces the probability of poor contact when the micro device is bonded, and does not need to mechanically press the micro device, thereby reducing damage to the micro device.

Description

Technical Field

[0001] This disclosure belongs to the field of microelectronic packaging and integration technology, and relates to a micro-device integration method, a micro-device and Micro-LED array integration method. Background Technology

[0002] With the rapid development of global electronic information technology, the requirements for the performance, functionality, and integration of electronic products are increasing. This directly drives the evolution of semiconductor devices towards miniaturization and high-density integration. Various micro-devices, such as micro-LEDs, micro-sensors, microelectromechanical systems (MEMS) devices, and other microchips in advanced packages, are being widely used in many cutting-edge fields such as high-resolution displays, wearable devices, the Internet of Things, medical electronics, and artificial intelligence hardware due to their unique performance advantages, becoming an important cornerstone for future technological development.

[0003] However, as the size of microdevices continues to shrink (typically from a few micrometers to tens of micrometers), their electrode spacing and effective bonding area also decrease dramatically, posing unprecedented challenges to large-scale, high-yield integration processes. Traditional integration and bonding technologies face numerous insurmountable problems when handling such delicate devices: Parallelism issues at the bonding interface: During large-scale integration, it is difficult to maintain ideal parallelism between the surfaces of the receiving substrate and the microdevice array, or slight warping and unevenness may exist. This causes the electrodes of some devices to fail to make effective contact with the corresponding electrodes of the receiving substrate, forming an open circuit, which seriously affects the integration yield.

[0004] The issue of bonding pressure uniformity: Even seemingly flat surfaces exhibit inhomogeneities at the microscale. Traditional bonding methods struggle to apply uniform bonding pressure across the entire array of microdevices, resulting in some areas having insufficient pressure and poor contact, while others have excessive pressure, potentially causing device damage or excessive deformation of the bonding material.

[0005] Short circuit between electrodes: With the miniaturization of device size and the reduction of electrode spacing, conductive bonding materials (such as solder) are prone to lateral propagation during bonding, leading to short circuits between adjacent electrodes, especially when bonding pressure is uneven or alignment is off. This not only reduces device reliability but also increases the failure rate.

[0006] Mechanical damage risk: Micro-devices are often fragile in structure, and traditional mechanical bonding methods may cause irreversible mechanical damage to the devices, such as cracks, scratches or damage to the internal structure, affecting their electrical and optical performance.

[0007] Efficiency and Cost Challenges: Currently, the industry largely employs a "detect-repair" strategy to address the aforementioned issues. This involves inspecting the entire array one by one after integration, and then repairing any defects found. However, for arrays composed of hundreds of thousands or even millions of microdevices, this strategy is inefficient, costly, and extremely time-consuming. It has become a core bottleneck restricting the large-scale commercial production of microdevices, severely limiting their widespread application and market expansion in various products. Summary of the Invention

[0008] To overcome the above problems, this disclosure provides a solution.

[0009] The technical solution disclosed herein is as follows: In a first aspect, this disclosure provides a method for integrating microdevices, including: A cathode electrode and an anode electrode are fabricated on a receiving substrate; Conductive bumps are respectively provided on the cathode electrode and anode electrode of the receiving substrate; An electrically insulating separation structure is provided to prevent the cathode electrode and anode electrode of the receiving substrate from being electrically connected. The microdevice is transferred to the target location and initially bonded to the receiving substrate, while the electrically insulating separation structure prevents the cathode and anode electrodes of the microdevice from being electrically connected. The conductive bumps are guided to deform and rise, thus electrically connecting the electrodes of the receiving substrate and the micro-device.

[0010] Furthermore, the material of the conductive bump is one of a low-melting-point metal or its alloy, a ductile conductive polymer, or a composite material containing deformable conductive particles.

[0011] Furthermore, the conductive bumps are deformed by heating, pressurizing, or ultrasonication.

[0012] Furthermore, the height of the electrically insulating separation structure is 2 micrometers to 2000 micrometers.

[0013] Furthermore, the electrically insulating separation structure can be a microwall, micropillar, isolation dam, or groove.

[0014] Furthermore, the material of the electrically insulating separation structure is one or more of photoresist, dielectric film, and polymer.

[0015] Furthermore, microdevices can be transferred using one of the following methods: thin-film assisted transfer, laser transfer, stamp transfer, electromagnetic transfer, pick-and-place technology, roller transfer, or fluid self-assembly transfer.

[0016] Secondly, this disclosure provides a microdevice that is integrated by the method described in the first aspect.

[0017] Furthermore, the micro-device is a Micro-LED, a micro-sensor, or a microelectromechanical system (MEMS) device.

[0018] Thirdly, this disclosure provides a method for integrating a Micro-LED array, including: An anode and a cathode electrode are fabricated on a driving substrate, and indium bumps are fabricated on the anode and cathode electrodes of the driving substrate, respectively. Microwalls are fabricated between the anode and cathode electrodes of the driving substrate using a photolithography process; The Micro-LED chip array is transferred to the target location and initially bonded to the driving substrate; The indium bumps are wet-reflowed to melt them and form a spherical structure, which is then electrically connected to the electrodes of the drive substrate and the Micro-LED chip.

[0019] This disclosure has the following beneficial effects: This disclosure provides an electrically insulating separation structure between the anode and cathode electrodes of the receiving substrate. The electrically insulating separation structure can guide the precise placement of microdevices during initial bonding and can also prevent short circuits caused by the lateral movement of conductive bumps when the conductive bumps deform.

[0020] After initial bonding, this method addresses situations where some electrodes have poor contact by increasing the height of the conductive bumps through deformation, thereby establishing a stable electrical connection between the poorly contacting electrodes. This method eliminates the need for mechanical pressing of the microdevice during bonding, reducing damage to the microdevice. Attached Figure Description

[0021] Figure 1 This is a partial schematic diagram of a Micro-LED device prepared according to an embodiment of the present disclosure.

[0022] Figure 2-6 This is a schematic diagram of the Micro-LED chip array integration method according to an embodiment of the present disclosure.

[0023] The reference numerals in the figure are as follows: 1. Driving substrate; 2. Anode electrode of driving substrate; 3. Cathode electrode of driving substrate; 4. Indium bump; 5. SU-8 microwall; 6. Micro-LED chip; 7. Micro-LED chip electrode; 8. Indium ball. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0025] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes. To keep the following description of the embodiments of this disclosure clear and concise, detailed descriptions of some known functions and components are omitted.

[0026] The present disclosure will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] In a first aspect, this disclosure provides a method for integrating microdevices, including: A cathode electrode and an anode electrode are fabricated on a receiving substrate; Conductive bumps are respectively provided on the cathode electrode and anode electrode of the receiving substrate; An electrically insulating separation structure is provided to prevent the cathode electrode and anode electrode of the receiving substrate from being electrically connected. The microdevice is transferred to the target location and initially bonded to the receiving substrate, while the electrically insulating separation structure prevents the cathode and anode electrodes of the microdevice from being electrically connected. The conductive bumps are guided to deform and rise, thus electrically connecting the electrodes of the receiving substrate and the micro-device.

[0028] In one embodiment of this disclosure, the material of the conductive bump is one of a low-melting-point metal or its alloy, a ductile conductive polymer, or a composite material containing deformable conductive particles.

[0029] In one embodiment of this disclosure, the conductive bumps are deformed by heating, pressurizing, or ultrasonication.

[0030] In one embodiment of this disclosure, the height of the electrically insulating separation structure is 2 micrometers to 2000 micrometers.

[0031] In one embodiment of this disclosure, the electrically insulating separation structure is a microwall, micropillar, isolation dam, or groove.

[0032] In one embodiment of this disclosure, the material of the electrically insulating separation structure is one or more combinations of photoresist, dielectric film, and polymer.

[0033] In one embodiment of this disclosure, a microdevice is transferred using one of the following methods: thin-film assisted transfer, laser transfer, stamp transfer, electromagnetic transfer, pick-and-place technology, roller transfer, and fluid self-assembly transfer.

[0034] Secondly, this disclosure provides a microdevice that is integrated by the method described in the first aspect.

[0035] In one embodiment of this disclosure, the micro-device is a Micro-LED, a micro-sensor, or a microelectromechanical system (MEMS) device.

[0036] Thirdly, refer to Figure 1-6 This disclosure provides a method for integrating a Micro-LED array, comprising: A driving substrate anode electrode 2 and a driving substrate cathode electrode 3 are fabricated on the driving substrate 1, and indium bumps 4 are fabricated on the driving substrate anode electrode 2 and the driving substrate cathode electrode 3, respectively. SU-8 microwalls 5 are fabricated between the anode electrode 2 and the cathode electrode 3 of the driving substrate using a SU-8 lithography machine via a photolithography process. The Micro-LED chip array is transferred to the target position and initially bonded to the driving substrate 1. During the initial bonding, there is poor contact between the Micro-LED chip electrode 7 of some Micro-LED chips 6 and the electrode of the driving substrate 1. The indium bump 4 is subjected to wet reflow to melt it and form a spherical structure, resulting in an indium ball 8, which is electrically connected to the electrodes of the driving substrate 1 and the Micro-LED chip 6.

[0037] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0038] The units described in the embodiments of this disclosure can be implemented in software or hardware. The names of the units are not, in some cases, intended to limit the specific unit.

[0039] The functions described above in this document can be performed at least in part by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), and so on.

[0040] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

[0041] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0042] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

[0043] The following points should be noted regarding this disclosure: (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0044] (2) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0045] The above description is merely an embodiment of this disclosure and does not limit the patent scope of this disclosure. Any equivalent structure made using the content of this disclosure and its drawings, or directly or indirectly applied to other related technical fields, is similarly included within the patent protection scope of this disclosure.

Claims

1. A method for integrating microdevices, characterized in that, include: A cathode electrode and an anode electrode are fabricated on a receiving substrate; Conductive bumps are respectively provided on the cathode electrode and anode electrode of the receiving substrate; An electrically insulating separation structure is provided to prevent the cathode electrode and anode electrode of the receiving substrate from being electrically connected. The microdevice is transferred to the target location and initially bonded to the receiving substrate, while the electrically insulating separation structure prevents the cathode and anode electrodes of the microdevice from being electrically connected. The conductive bumps are guided to deform and rise, thus electrically connecting the electrodes of the receiving substrate and the micro-device.

2. The microdevice integration method according to claim 1, characterized in that, The material of the conductive bump is one of a low-melting-point metal or its alloy, a ductile conductive polymer, or a composite material containing deformable conductive particles.

3. The microdevice integration method according to claim 2, characterized in that, The conductive bumps are deformed by heating, pressurizing, or ultrasonication.

4. The microdevice integration method according to claim 1, characterized in that, The height of the electrically insulating separation structure ranges from 2 micrometers to 2000 micrometers.

5. The microdevice integration method according to claim 1, characterized in that, Electrically insulating separation structures are microwalls, micropillars, isolation dams, or grooves.

6. The microdevice integration method according to claim 1, characterized in that, The material of the electrically insulating separation structure is one or more of photoresist, dielectric film, and polymer.

7. The microdevice integration method according to claim 1, characterized in that, Microdevices are transferred using one of the following methods: thin-film assisted transfer, laser transfer, stamp transfer, electromagnetic transfer, pick-and-place technology, roller transfer, and fluid self-assembly transfer.

8. A micro-device, characterized in that, It is obtained by integrating the method described in any one of claims 1-7.

9. The microdevice according to claim 8, characterized in that, This micro-device is a Micro-LED, a micro-sensor, or a microelectromechanical system (MEMS) device.

10. A method for integrating a Micro-LED array, characterized in that, include: An anode and a cathode electrode are fabricated on a driving substrate, and indium bumps are fabricated on the anode and cathode electrodes of the driving substrate, respectively. Microwalls are fabricated between the anode and cathode electrodes of the driving substrate using a photolithography process; The Micro-LED chip array is transferred to the target location and initially bonded to the driving substrate; The indium bumps are wet-reflowed to melt them and form a spherical structure, which is then electrically connected to the electrodes of the drive substrate and the Micro-LED chip.

Images