Magnetic spring needle for mass transfer

Abstract

The invention discloses a magnetic spring needle for mass transfer, which belongs to the technical field of chip mass transfer and comprises a magnetic needle rod, the lower end of the magnetic needle rod is connected with a connector, the lower end of the connector is connected with a positioning sleeve, the lower end of the positioning sleeve is connected with a connecting piece, and the lower end of the connecting piece is connected with a magnetic needle tip. A first magnet, a second magnet and a guide block which are sequentially arranged from top to bottom are arranged in the positioning sleeve, and the connector is connected with the magnetic needle rod and the first magnet; according to the magnetic spring needle for mass transfer, the elastic buffering function is achieved through repulsive force between the permanent magnets, a chip is transferred to a drive board without damage through the flexible material of the needle point of the magnetic needle, the expected service life of equipment is prolonged, and the equipment cost of mass transfer is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chip mass transfer, and in particular to a magnetic spring needle for mass transfer. Background Art

[0002] Micro LED (micro light-emitting diode) is regarded as the core direction of the next-generation display technology, with advantages such as ultra-high performance (self-luminous, high brightness, strong contrast, far exceeding OLED and LCD), extremely long lifespan (inorganic materials without screen burn, lifespan exceeding 100,000 hours), and extreme miniaturization (single chip <50μm, supporting 8K+ ultra-high resolution). However, the mass production bottleneck lies in the mass transfer process, which requires precise transfer of millions of chips with a yield >99.999%. Mass transfer is a core process in fields such as semiconductors and Micro LED. Existing solutions have defects. Traditional mechanical picking has low efficiency, laser lift-off has a thermal effect that damages components and limits substrate materials. Although the needle-punching technology has been widely and maturely applied, as the chip size shrinks, traditional contact tools are prone to picking failures, chip cracking, etc., and there are also problems of metal fatigue.

[0003] The existing authorized invention patent 202322635962.1, "A Piezoelectric Effect Needle-Punching Mass Transfer Device", uses the inverse piezoelectric effect to drive the ejector pin to achieve short-distance rapid start and stop, and the pneumatic system can reduce chip damage. However, the gas path is complex and costly, and there is also a hidden danger of gas source leakage. The existing authorized invention patent 202420574892.5, "A Spring Probe for Semiconductor Packaging and Testing", fixes the spring through a spring installation unit, enabling the probe to automatically reset when contracting. Although there is elastic buffering to reduce pressure fluctuations, due to the metal fatigue characteristics, the yield drops sharply with the number of uses. The existing application for invention patent 202410008647.2, "A Voice Coil Motor-Driven Hydraulic Needle-Punching Mass Transfer Mechanism", uses a voice coil motor to drive a buffer needle to achieve chip mass transfer. However, this solution relies on a sealed liquid to apply pressure to the needle-punching mechanism. Long-term high-frequency movement is prone to wear of the seal and leakage of the liquid to contaminate the chip, and the pressure transmission lags, making it difficult to meet the requirements of instantaneous precise control. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetic spring needle for mass transfer, which realizes magnetic buffering through the repulsive force between magnets, replaces the traditional mechanical spring, thereby avoiding metal fatigue and extending the service life to meet the mass transfer requirements of Micro LED and other semiconductor chips.

[0005] To achieve the above object, the present invention provides a magnetic spring needle for mass transfer, including a magnetic needle rod, a connector is connected to the lower end of the magnetic needle rod, a positioning sleeve is connected to the lower end of the connector, a connecting member is connected to the lower end of the positioning sleeve, and a magnetic needle tip is connected to the lower end of the connecting member. A first magnet, a second magnet and a guiding block are arranged in the positioning sleeve in sequence from top to bottom, and the connector connects the magnetic needle rod and the first magnet.

[0006] Preferably, the first magnet and the second magnet are neodymium iron boron permanent magnets, and the lower surface of the first magnet and the upper surface of the second magnet are of the same magnetic pole, forming a compressible magnetic elastic structure.

[0007] Preferably, the diameters of the first magnet and the second magnet are both 5 mm to 6 mm, the height of the first magnet is 8 mm to 10 mm, and the height of the second magnet is 6 mm to 8 mm.

[0008] Preferably, the elastic length range of the air gap between the first magnet and the second magnet is 2 mm to 5 mm. According to the magnetic force calculation formula, within the elastic length range, the generated magnetic force is 0.1 N to 0.7 N.

[0009] Preferably, the magnetic needle rod, the connector, the positioning sleeve, the connecting member and the guiding block are all made of non-magnetic materials, and the non-magnetic materials are one or more of stainless steel, aluminum alloy, copper alloy and ceramic.

[0010] Preferably, the inside of the positioning sleeve is coated with an anti-magnetic interference material to avoid the interference of external magnetic fields.

[0011] Preferably, the magnetic needle tip adopts a split structure and is fixedly connected to the connecting member through a detachable connection structure of snap connection. The detachable connection structure is used to replace different specifications of the needle tip in different occasions.

[0012] Preferably, the contact end of the magnetic needle tip is provided with a cylindrical working surface, and the surface of the working surface is coated with a flexible protective layer made of polyurethane or silica gel to avoid contact damage to the chip.

[0013] Preferably, a force sensor and a displacement sensor are arranged inside the magnetic needle tip to detect the changes of force and displacement during work and update the future movement direction of the spring magnetic needle in real time.

[0014] Therefore, the magnetic spring needle for mass transfer adopting the above structure in the present invention has the following beneficial effects:

[0015] (1) Two cylindrical permanent magnets arranged with opposite polarities up and down are used to replace the traditional mechanical spring with magnetic pole repulsion force, forming a non-contact elastic buffer mechanism, which completely solves the inherent defects of metal spring fatigue fracture and large pressure fluctuation;

[0016] (2) The magnetic repulsion force changes non-linearly with the distance, and can achieve flexible pressure self-adaptive adjustment within the micron-level displacement range. It can not only avoid contact damage to ultra-thin components such as Micro LED, but also accurately match the different height requirements of chips with different shapes;

[0017] (3) The modular design further strengthens the practicability. The detachable needle tip supports quick replacement of multiple specifications and adapts to different application scenarios;

[0018] (4) The design of neodymium iron boron magnet with anti-oxidation coating can maintain magnetic stability in different environments. The service life exceeds tens of millions of cycles, and the comprehensive operation and maintenance cost is greatly reduced compared with the traditional scheme. Brief Description of the Drawings

[0019] Figure 1 It is a cross-sectional view of the overall structure of a magnetic spring needle for mass transfer according to the present invention;

[0020] Figure 2 It is a schematic diagram of the overall structure of a magnetic spring needle for mass transfer according to the present invention;

[0021] Figure 3 It is a graph showing the change of magnetic force with distance of a magnetic spring needle for mass transfer according to the present invention;

[0022] Figure 4 It is an application schematic diagram of a magnetic spring needle for mass transfer according to the present invention;

[0023] Reference numerals: 1, magnetic needle rod; 2, connector; 3, positioning sleeve; 4, connecting piece; 5, magnetic needle tip; 6, first magnet; 7, second magnet; 8, guide block; 9, fixing component; 10, installation groove; 11, vision calibration system; 12, slide rail. Detailed Description of the Invention

[0024] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0025] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0026] Embodiment

[0027] As Figure 1 and Figure 2 shown, a magnetic spring needle for massive transfer includes a magnetic needle rod 1. A connector 2 is connected to the lower end of the magnetic needle rod 1. A positioning sleeve 3 is connected to the lower end of the connector 2. The interior of the positioning sleeve 3 is coated with an anti-magnetic interference material to avoid interference from external magnetic fields. A connector 4 is connected to the lower end of the positioning sleeve 3. A magnetic needle tip 5 is connected to the lower end of the connector 4. The magnetic needle rod 1, the connector 2, the positioning sleeve 3, the connector 4 and the guide block 8 are all made of non-magnetic materials, and the non-magnetic materials are one or more of stainless steel, aluminum alloy, copper alloy, and ceramic.

[0028] Inside the positioning sleeve 3, a first magnet 6, a second magnet 7 and a guide block 8 are arranged in sequence from top to bottom. The connector 2 connects the magnetic needle rod 1 and the first magnet 6. The first magnet 6 and the second magnet 7 are neodymium iron boron permanent magnets. The first magnet 6 and the second magnet 7 are pre-magnetized before assembly to ensure a uniform magnetic field. The surface of the permanent magnet is coated with an anti-oxidation layer to extend its service life. The lower surface of the first magnet 6 and the upper surface of the second magnet 7 are the same magnetic poles, forming a compressible magnetic elastic structure. The diameters of both the first magnet 6 and the second magnet 7 are 5 mm to 6 mm. The height of the first magnet 6 is 8 mm to 10 mm. The height of the second magnet 7 is 6 mm to 8 mm. The elastic length range of the air gap between the first magnet 6 and the second magnet 7 is 2 mm to 5 mm. According to the magnetic force calculation formula, within the elastic length range, the generated magnetic force is 0.1 N to 0.7 N. The curve of the magnetic force changing with distance is as Figure 3 shown.

[0029] The tip 5 of the magnetic needle adopts a split structure and is fixedly connected to the connecting member 4 through a detachable connection structure connected by a buckle. The detachable connection structure is used to replace tips of different specifications on different occasions. The contact end of the tip 5 of the magnetic needle is provided with a cylindrical working surface, and the surface of the working surface is coated with a flexible protective layer made of polyurethane or silica gel to avoid contact damage to the chip. A force sensor and a displacement sensor are arranged inside the tip 5 of the magnetic needle to detect changes in force and displacement during operation and update the future movement direction of the spring magnetic needle in real time.

[0030] Working principle: As Figure 4 shown, the magnetic spring needle is integrated on the moving platform of the mass transfer device through the fixing component 9 and is installed on two slide rails 12 together with the vision calibration system 11 to achieve synchronous movement. During operation, the substrate with the chip is fixed above the installation slot 10, and the substrate to be transferred is fixed below the installation slot 10. The two substrates are aligned by scanning the fiducial marks through the vision calibration system 11. During mass transfer, the magnetic spring needle pierces the chips one by one from above onto the substrate below and uses the vision calibration system 11 for positioning. The specific working process of the magnetic spring needle is that the needle rod 1 of the magnetic needle is positioned above the target chip under the drive of the slide rail 12, and the connector transmits the driving force of the moving platform to the first magnet 6, pushing the tip 5 of the magnetic needle to contact the surface of the chip. At this time, the first magnet 6 and the second magnet 7 with the same poles facing each other inside the positioning sleeve 3 generate a magnetic repulsive force buffer due to pressure, and the guiding block 8 restricts the second magnet 7 to axially compress the air gap to form a controllable elastic resistance. When the magnetic repulsive force reaches the threshold, the tip 5 of the magnetic needle fixes the chip through internal vacuum adsorption, and the connecting member 4 synchronously transmits the adsorption signal to the control system. Subsequently, the moving platform carries the magnetic spring needle to cross to the target position of the substrate to be transferred, and the magnetic repulsive force gradually weakens as the air gap expands. The tip 5 of the magnetic needle releases the chip. During the transfer process, the vision calibration system 11 detects the chip offset in real time and dynamically calibrates the position, and finally completes the high-precision and non-destructive transfer.

[0031] Therefore, the present invention adopts a magnetic spring needle for mass transfer with the above structure, realizes the elastic buffering function through the repulsive force between permanent magnets, and realizes the transfer of the chip to the driving board without damage through the flexible material of the tip of the magnetic needle, improves the expected service life of the device, and reduces the equipment cost of mass transfer; has the advantages of high precision, high reliability, strong compatibility, etc., and provides an efficient and zero-damage mass transfer solution for precision manufacturing fields such as Micro LED and semiconductor packaging.

[0032] Finally, it should be noted that the above embodiments are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent replacements or changes, and should be covered within the protection scope of the present invention.

Claims

1. A magnetic spring needle for mass transfer, characterized in that: It comprises a magnetic needle rod, the lower end of which is connected to a connector, the lower end of which is connected to a positioning sleeve, the lower end of which is connected to a connector, the lower end of which is connected to a magnetic needle tip, a first magnet, a second magnet and a guide block arranged in sequence from top to bottom are arranged inside the positioning sleeve, and the connector connects the magnetic needle rod and the first magnet.

2. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The first magnet and the second magnet are neodymium iron boron permanent magnets, and the lower surface of the first magnet and the upper surface of the second magnet have the same magnetic pole.

3. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The diameters of the first magnet and the second magnet are both 5 mm to 6 mm, the height of the first magnet is 8 mm to 10 mm, and the height of the second magnet is 6 mm to 8 mm.

4. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The elastic length of the air gap between the first magnet and the second magnet ranges from 2 mm to 5 mm, and the magnitude of the generated magnetic force ranges from 0.1 N to 0.7 N.

5. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The magnetic needle rod, the connector, the positioning sleeve, the connector and the guide block are all made of non-magnetic materials.

6. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The interior of the positioning sleeve is coated with anti-magnetic interference material.

7. The magnetic spring needle for mass transfer according to claim 1, characterized in that: The magnetic needle tip adopts a split structure and is fixedly connected to the connecting piece via a detachable connecting structure connected by a snap.

8. The magnetic spring needle for mass transfer according to claim 7, characterized in that: The contact end of the magnetic needle tip is provided with a cylindrical working surface, and the surface of the working surface is covered with a flexible protective layer of polyurethane or silicone material.

9. The magnetic spring needle for mass transfer according to claim 8, characterized in that: A force sensor and a displacement sensor are arranged inside the magnetic needle tip.

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