CN113451456A - Laser eutectic welding device and method for micro LED chip and control substrate - Google Patents
Laser eutectic welding device and method for micro LED chip and control substrate Download PDFInfo
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- CN113451456A CN113451456A CN202110692620.6A CN202110692620A CN113451456A CN 113451456 A CN113451456 A CN 113451456A CN 202110692620 A CN202110692620 A CN 202110692620A CN 113451456 A CN113451456 A CN 113451456A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
- B23K37/04—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work
- B23K37/0426—Fixtures for other work
- B23K37/0435—Clamps
- B23K37/0443—Jigs
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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
- H01L21/6838—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 with gripping and holding devices using a vacuum; Bernoulli devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier 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
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
- H01L2933/0066—Processes relating to semiconductor body packages relating to arrangements for conducting electric current to or from the semiconductor body
Abstract
The invention discloses a laser eutectic welding device for a micro LED chip and a control substrate, wherein a plurality of LED wafers in the micro LED chip (1) and the control substrate (2) are welded together by laser; the laser eutectic welding device includes: a negative pressure adsorption unit (4) for adsorbing the micro LED chip (1) and placing it on the control substrate (2); and the laser emitting system (6) is positioned above the micro LED chip (1) and is used for heating welding points of the plurality of first positive electrodes (13), the plurality of second positive electrodes (22) and the first negative electrode (12) and the second negative electrode (23) by emitting laser to complete simultaneous eutectic welding. According to the invention, the temperature of the heating area can be accurately controlled by adopting the laser heating temperature, modular transfer eutectic welding of the Micro LEDs is realized, and secondary melting of a single transfer eutectic welding point of a single Micro LED is avoided. Meanwhile, eutectic welding speed is high by transferring the micro LED modules in an array mode, and the eutectic speed is effectively improved.
Description
Technical Field
The invention belongs to the technical field of miniature LEDs, and particularly relates to a laser eutectic welding device and method for a miniature LED chip and a control substrate.
Background
Micro LED (Micro LED) technology is LED Micro matrixing technology, refers to a high-density Micro-micron LED array integrated on a chip, and is widely applied to the fields of display screens, visible light communication, intelligent portable equipment and the like. The LED has the advantages of stable performance, long service life and the like, and simultaneously has the advantages of low LED power consumption, high reaction speed, strong contrast and the like. Meanwhile, the advantages of low power consumption, color saturation, high reaction speed, high contrast and the like of the LED are also inherited, the brightness of the Micro LED is 30 times higher than that of the OLED, and the energy consumption is about 10% of that of the LCD and 50% of that of the OLED.
The Micro LED has great application prospect in the future, but the current problem of manufacturing cost of the Micro LED seriously affects the commercialization process of the Micro LED, the reason is that the bottleneck of a huge transfer technology is still broken through, the traditional huge transfer is single transfer single eutectic welding, the single transfer severely limits the mass production process of the Micro LED, as the resolution ratio of the Micro LED is higher, a very small Micro LED display screen contains a large number of LED wafers, such as a Micro LED display screen with about 0.39 inch, the number of the contained LED wafers is about 240 ten thousand, if a single transfer method is adopted, the time and labor are particularly consumed, the implementation is difficult, the single eutectic welding can greatly reduce the product qualification rate, the reason is that after one LED wafer is transferred, the control substrate is welded with the control substrate by heating, and after the next LED wafer is transferred, the control substrate is heated integrally, the second LED chip and the control substrate are welded together, and the welding point of the first LED chip is melted when the control substrate is heated integrally. The problem of secondary multiple melting occurs, the LED wafer is damaged, and the product percent of pass is seriously influenced.
To solve this problem, the present invention is proposed.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a Micro-LED chip eutectic method, which can realize eutectic of a chip with larger capacity and a control substrate. Mainly lie in the following several aspects: 1. the invention provides a method for acquiring position information of a Micro LED chip and a control substrate by adopting a high-definition camera and matching with a high-precision alignment platform to perform high-precision alignment of the Micro LED chip and the control substrate. 2. The invention provides a quartz negative pressure adsorption device made of colorless and transparent quartz materials and used as a Micro LED chip taking and fixing device 3. 4. In the eutectic process, a sapphire lining plate of a Micro LED is not required to be removed, and the sapphire lining plate is directly adsorbed by a quartz negative pressure adsorption device to enable the equipment to complete eutectic welding work. 5. The invention adopts a module transfer laser heating eutectic welding method. Laser plane light beam penetrates through the quartz negative pressure adsorption device to heat and weld the aligned and fixed Micro LED and the control substrate
The invention provides a laser eutectic welding device for a micro LED chip and a control substrate, aiming at simultaneously welding a plurality of LED wafers in the micro LED chip 1 and the control substrate 2 together by using laser;
the micro LED chip 1 comprises a chip substrate 15 and a plurality of LED chips 11 fixed on the chip substrate 15; the plurality of LED chips 11 have a common first negative electrode 12, and the plurality of LED chips 11 have independent first positive electrodes 13, respectively;
the control substrate 2 is positioned below the micro LED chip 1 and comprises a control substrate main body 21 and a plurality of second positive electrodes 22 and a second negative electrode 23 positioned on the control substrate main body 21;
the laser eutectic welding device includes:
a negative pressure adsorption unit 4 for adsorbing the micro LED chip 1 and placing it on the control substrate 2;
and the laser emitting system 6 is positioned above the micro LED chip 1 and is used for heating welding points of the first positive electrodes 13, the second positive electrodes 22 and the first negative electrodes 12 and the second negative electrodes 23 by emitting laser to complete simultaneous eutectic welding.
An LED chip, also known as an LED bead, is essentially an LED light emitting diode.
Preferably, the number of said second positive electrodes 22 is equal to the number of said first positive electrodes 13; and the positions of the first positive electrode 13 and the second positive electrode 22 correspond, and the precision deviation is less than 0.7 μm.
Preferably, the first negative electrode 12 and the second negative electrode 23 are both one and planar, and the plurality of LED chips 11 are electrically connected to the control substrate 2 in a manner of common cathode.
Preferably, the laser eutectic welding device further comprises an image acquisition unit 3, which is used for acquiring images of the micro LED chip 1 and the control substrate 2, wherein the image acquisition unit 3 is connected with an external computer host, and can send the acquired images to the external computer host; the image acquisition unit 3 includes a plurality of CCD cameras. The CCD camera adopts a high-resolution camera, so that the positioning is more accurate and the image acquisition is clearer.
Preferably, the negative pressure adsorption unit 4 includes a negative pressure adsorption unit main body 41, an air extraction opening 42 and a negative pressure adsorption hole 43, the air extraction opening 42 is connected with an air extraction device, air in the negative pressure adsorption unit main body 41 is extracted, so that the negative pressure adsorption hole 43 is in a negative pressure environment, and then a suction force is generated to absorb the micro LED chip 1. The middle of the negative pressure adsorption unit body 41 is a cavity, and two sides of the cavity are respectively provided with an air extraction opening 42, so that negative pressure is formed in the cavity to adsorb the tested component. One surface of the negative pressure adsorption unit for adsorbing the components is provided with a negative pressure adsorption hole 43.
The negative pressure adsorption unit body 41 is provided with an infrared reflection resistant or laser reflection resistant film, so that infrared or laser is prevented from being reflected by the negative pressure adsorption unit body 41. Therefore, the laser emitting system 6, emitting laser, passes through the negative pressure adsorption unit body 41 to heat the welding points of the first positive electrodes 13 and the second positive electrodes 22, and the first negative electrodes 12 and the second negative electrodes 23, thereby completing eutectic welding. This film is plated on quartz (negative pressure adsorption unit body 41), and the material may be selected from: silicon monoxide, magnesium fluoride, zinc sulfide, and the like.
Preferably, the negative pressure adsorption unit main body 41 is transparent and is selected from transparent materials such as quartz, glass and the like; the negative pressure adsorption holes 43 are distributed around the periphery outside the display area of the chip substrate 15 and avoid the positions of alignment target points, and the area occupied by the negative pressure adsorption holes 43 is smaller than that of the chip substrate 15. The high-light-transmission quartz material can enable the CCD high-resolution camera to better collect the positioning target and the Micro LED performance image on the Micro LED original piece. The negative pressure adsorption holes 43 are distributed around the periphery outside the display area of the chip substrate 15, so that the influence of the opening (the negative pressure adsorption holes 43) on the CCD high-resolution camera on the sampling and image acquisition of the micro LED chip can be avoided.
Alignment target points are first alignment target 14 and second alignment target 24.
Preferably, the chip substrate 15 further has a first alignment target 14 thereon, and the control substrate body 21 has a second alignment target 24 thereon; the first alignment target 14 and the second alignment target 24 are matched, so that the micro LED chip 1 corresponds to the control substrate 2, the first positive electrode 13 is electrically connected to the second positive electrode 22, and the first negative electrode 12 is electrically connected to the second negative electrode 23.
Preferably, the first alignment target 14 is a small square, and the second alignment target 24 is four separate small squares, wherein the four separate small squares are two by two juxtaposed to form a large square with a space cross shape in the middle, the four separate small squares are respectively located at four corners of the large square, the small square of the first alignment target 14 can just fit into the cross intersection of the space cross shape, and the space between the small squares of each of the second alignment targets 24 at the periphery is equal.
Preferably, the laser eutectic welding device further comprises a precise alignment platform 5, and the precise alignment platform 5 can control the control substrate 2 to move to align at X, Y, Z and theta axis;
the accurate alignment platform 5 is also connected with an external computer host, the micro LED chip 1 and the control substrate 2 are caused to correspond in position by the first alignment target 14 and the second alignment target 24, the image acquisition unit 3 acquires images of the first alignment target 14 and the second alignment target 24 and feeds the image information back to the external computer host, and the computer host further adjusts the positions of the first alignment target 14 and the second alignment target 24 by regulating and controlling the accurate alignment platform 5 according to the image information and a set value.
The second aspect of the present invention provides a laser eutectic bonding method for a micro LED chip, using the laser eutectic bonding apparatus of the first aspect of the present invention, comprising the steps of:
A. the negative pressure adsorption unit 4 adsorbs the micro LED chip 1 and places the micro LED chip on the control substrate 2;
B. the micro LED chip 1 and the control substrate 2 are aligned and attached together;
C. the laser eutectic welding system 6 works to heat the butt joint and complete the welding.
Preferably, the alignment between the micro LED chip 1 and the control substrate 2 is completed through the image acquisition unit 3 and the precise alignment platform 5.
According to the laser eutectic welding method, a laser system is adopted to heat, melt and attach metal electrodes in contact with welding points, firstly, a quartz negative pressure adsorption device takes materials from a material placing box, Micro LEDs and control substrate position information are collected through a high-definition camera, and alignment is carried out through a high-precision alignment platform. After the alignment is finished, the high-precision alignment platform rises to enable the Micro LED and the control substrate to be attached together. And then, the laser system works to heat the welding point, and finally the Micro LED and the control substrate are pasted, welded together.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the temperature of the heating area can be accurately controlled by adopting the laser heating temperature, modular transfer eutectic welding of the Micro LEDs is realized, and secondary melting of a single transfer eutectic welding point of a single Micro LED is avoided, so that the Micro LED is prevented from being damaged.
2. According to the invention, eutectic soldering speed is fast transferred in an array mode by using Micro LED modules, and the eutectic speed is effectively improved.
3. The Micro LED and a metal electrode (InSn) on the control basic surface are heated and melted by laser, and finally the Micro LED and the metal electrode are combined together without adding other solders. The working procedure of adding solder is reduced, and the production cost is saved.
4. The laser beam shaping system shapes the laser beam into a plane beam with uniform energy density distribution, and is matched with the focusing mirror to ensure that the size of a laser spot irradiated on the eutectic welding platform is matched with the size of the eutectic welding chip. When the size of the eutectic welding chip is changed, the size of the laser beam is correspondingly changed and adjusted.
5. The present invention electrically connects a plurality of LED chips 11 to the control board 2 in a common cathode manner.
6. The invention designs a negative pressure adsorption unit 4 independently, which is used for adsorbing the micro LED chip 1 and placing the micro LED chip on the control substrate 2. By adopting a negative pressure adsorption method, the Micro LED is more convenient to grab and is not easy to shift. Further, the negative pressure adsorption unit body 41 is made of transparent materials such as quartz and glass, and due to the high light transmittance of the negative pressure adsorption unit body 41, high-resolution shooting positioning can be accurate and Micro LED lighting information can be accurately collected.
7. The laser eutectic welding device further comprises an alignment target and a precise alignment platform 5, wherein the image acquisition unit 3 and the precise alignment platform 5 are connected with an external computer host, the micro LED chip 1 and the control substrate 2 are enabled to correspond in position through the first alignment target 14 and the second alignment target 24, the image acquisition unit 3 acquires images at the first alignment target 14 and the second alignment target 24 and feeds back the image information to the external computer host, and the computer host further adjusts the positions of the first alignment target 14 and the second alignment target 24 by regulating and controlling the precise alignment platform 5 according to the image information and a set value, so that the alignment of the micro LED chip and the control substrate 2 is accurate.
8. The first contraposition target 14 is a small square, the second contraposition target 24 is four separated small squares, wherein the four separated small squares are pairwise juxtaposed to form a large square with a space cross shape in the middle, the four separated small squares are respectively positioned at four corners of the large square, the small square of the first contraposition target 14 can be just arranged at the cross intersection of the space cross shape, the gap between the small squares of the second contraposition target 24 at the periphery is equal, and the corresponding accuracy or deviation value of the first positive electrode 13 and the second positive electrode 22 can be controlled by controlling the gap. The shape of the first alignment target 14 and the second alignment target 24 can precisely control the positions of the micro LED chips and the control substrate 2 to correspond in four directions, and the precision can be controlled to be less than 0.7 micrometers, the reason for limiting the position to be less than 0.7 micrometers is that the gap between two adjacent LED chips is 0.74 micrometers, and it is ensured that the offset error is less than 0.7 micrometers, so as to ensure that when the first positive electrode 13 and the second positive electrode 22 do not correspond in position even a little, a gap is still present between the first positive electrode 13 and the second positive electrode 22 beside the second positive electrode 22 that should correspond to the first positive electrode 13, so as to avoid short circuit. The shape of the alignment target is very critical, because for the transfer of a single LED chip, the accuracy of controlling the transfer of the single LED chip to the control substrate is easy due to the small size of the single LED chip, and for the micro LED array, the accuracy of controlling the transfer of the micro LED array to multiple directions is difficult due to the large size of the micro LED array. The alignment method can control the precision to be below 0.7 micron.
9. In the eutectic process, a sapphire lining plate of a Micro LED is not required to be removed, and the sapphire lining plate is directly adsorbed by a quartz negative pressure adsorption device to enable the equipment to complete eutectic welding work. In the prior art, a chip substrate of a sapphire lining plate is removed firstly, and then LED chips are normally arranged on a control substrate, the sapphire lining plate of a Micro LED is not required to be removed, the sapphire lining plate is directly adsorbed by a quartz negative pressure adsorption device and is inversely arranged on the control substrate, then the equipment finishes eutectic welding work, and the transfer and eutectic speed is effectively improved.
Drawings
FIG. 1 is a schematic structural view of a laser eutectic welding device for a micro LED chip and a control substrate according to the present invention;
fig. 2 is a top view of the control substrate 2 of the laser eutectic bonding apparatus of the present invention, wherein the first alignment target 14 and the second alignment target 24 are not matched;
FIG. 3 is a top view of the control substrate 2 after the first alignment target 14 and the second alignment target 24 have been mated according to the present invention;
FIG. 4 is a schematic structural view of the negative pressure adsorption unit 4 in the sorting apparatus according to the present invention;
FIG. 5 is a top view of the negative pressure adsorption unit 4 in the sorting apparatus according to the present invention;
FIG. 6 is a left side view of the negative pressure adsorption unit 4 in the sorting apparatus according to the present invention;
FIG. 7 is a flow chart of the method for detecting the quality of the micro LED chip according to the present invention;
the names of the reference symbols are: the system comprises a 1-micro LED chip, a 11-LED wafer, a 12-first negative electrode, a 13-first positive electrode, a 14-first alignment target, a 15-chip substrate, a 2-control substrate, a 21-control substrate main body, a 22-second positive electrode, a 23-second negative electrode, a 24-second alignment target, a 3-image acquisition unit, a 4-negative pressure adsorption unit, a 41-negative pressure adsorption unit main body, a 42-air extraction opening, a 43-negative pressure adsorption hole, a 5-precise alignment platform and a 6-laser emission system.
Detailed Description
The present invention will be described in further detail with reference to examples.
It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The materials or equipment used are not indicated by manufacturers, and all are conventional products available by purchase.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Further, "connected" as used herein may include wirelessly connected.
In the description of the present invention, "a plurality" means two or more unless otherwise specified. The terms "inner," "upper," "lower," and the like, refer to an orientation or a state relationship based on that shown in the drawings, which is for convenience in describing and simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "provided" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. To those of ordinary skill in the art, the specific meanings of the above terms in the present invention are understood according to specific situations.
It will be understood by those skilled in the art that, unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Example 1
The embodiment provides a laser eutectic welding device for a micro LED chip and a control substrate, and aims to weld a plurality of LED wafers in the micro LED chip 1 and the control substrate 2 together by using laser;
the micro LED chip 1 comprises a chip substrate 15 and a plurality of LED chips 11 fixed on the chip substrate 15; the plurality of LED chips 11 have a common first negative electrode 12, and the plurality of LED chips 11 have independent first positive electrodes 13, respectively;
the control substrate 2 is positioned below the micro LED chip 1 and comprises a control substrate main body 21 and a plurality of second positive electrodes 22 and a second negative electrode 23 positioned on the control substrate main body 21;
the laser eutectic welding device includes:
a negative pressure adsorption unit 4 for adsorbing the micro LED chip 1 and placing it on the control substrate 2;
and the laser emitting system 6 is positioned above the micro LED chip 1 and is used for heating welding points of the first positive electrodes 13, the second positive electrodes 22 and the first negative electrodes 12 and the second negative electrodes 23 by emitting laser to complete simultaneous eutectic welding.
An LED chip, also known as an LED bead, is essentially an LED light emitting diode.
The number of the second positive electrodes 22 is equal to the number of the first positive electrodes 13; and the positions of the first positive electrode 13 and the second positive electrode 22 correspond, and the precision deviation is less than 0.7 μm.
The first negative electrode 12 and the second negative electrode 23 are both one and planar, and the plurality of LED chips 11 are electrically connected to the control substrate 2 in a common cathode manner.
The laser eutectic welding device further comprises an image acquisition unit 3, the image acquisition unit 3 is used for acquiring images of the micro LED chip 1 and the control substrate 2, and the image acquisition unit 3 is connected with an external computer host and can send the acquired images to the external computer host; the image acquisition unit 3 includes a plurality of CCD cameras. The CCD camera adopts a high-resolution camera, so that the positioning is more accurate and the image acquisition is clearer.
The negative pressure adsorption unit 4 comprises a negative pressure adsorption unit main body 41, an air suction port 42 and a negative pressure adsorption hole 43, wherein the air suction port 42 is connected with an air suction device, air in the negative pressure adsorption unit main body 41 is sucked out, so that the negative pressure adsorption hole 43 is in a negative pressure environment, suction force is generated, and the micro LED chip 1 is sucked. The middle of the negative pressure adsorption unit body 41 is a cavity, and two sides of the cavity are respectively provided with an air extraction opening 42, so that negative pressure is formed in the cavity to adsorb the tested component. One surface of the negative pressure adsorption unit for adsorbing the components is provided with a negative pressure adsorption hole 43.
The negative pressure adsorption unit main body 41 is transparent and is made of quartz transparent materials; the negative pressure adsorption holes 43 are distributed around the periphery outside the display area of the chip substrate 15 and avoid the positions of alignment target points, and the area occupied by the negative pressure adsorption holes 43 is smaller than that of the chip substrate 15. The high-light-transmission quartz material can enable the CCD high-resolution camera to better collect the positioning target and the Micro LED performance image on the Micro LED original piece. The negative pressure adsorption holes 43 are distributed around the periphery outside the display area of the chip substrate 15, so that the influence of the opening (the negative pressure adsorption holes 43) on the CCD high-resolution camera on the sampling and image acquisition of the micro LED chip can be avoided.
Alignment target points are first alignment target 14 and second alignment target 24.
The chip substrate 15 is also provided with a first alignment target 14, and the control substrate body 21 is provided with a second alignment target 24; the first alignment target 14 and the second alignment target 24 are matched, so that the micro LED chip 1 corresponds to the control substrate 2, the first positive electrode 13 is electrically connected to the second positive electrode 22, and the first negative electrode 12 is electrically connected to the second negative electrode 23.
The first alignment target 14 is a small square, the second alignment target 24 is four separated small squares, the four separated small squares are two by two parallel to form a large square with a space cross shape in the middle, the four separated small squares are respectively positioned at four corners of the large square, the small square of the first alignment target 14 can be just arranged at the cross intersection of the space cross shape, and the gap between the small squares of the second alignment target 24 at the periphery is equal.
The laser eutectic welding device further comprises a precise alignment platform 5, wherein the precise alignment platform 5 can control the control substrate 2 to move to align at X, Y, Z and theta axis;
the accurate alignment platform 5 is also connected with an external computer host, the micro LED chip 1 and the control substrate 2 are caused to correspond in position by the first alignment target 14 and the second alignment target 24, the image acquisition unit 3 acquires images of the first alignment target 14 and the second alignment target 24 and feeds the image information back to the external computer host, and the computer host further adjusts the positions of the first alignment target 14 and the second alignment target 24 by regulating and controlling the accurate alignment platform 5 according to the image information and a set value.
The laser eutectic welding method for the micro LED chip by using the laser eutectic welding device comprises the following steps of:
A. the negative pressure adsorption unit 4 adsorbs the micro LED chip 1 and places the micro LED chip on the control substrate 2;
B. the micro LED chip 1 and the control substrate 2 are aligned and attached together;
C. the laser eutectic welding system 6 works to heat the butt joint and complete the welding.
The alignment of the micro LED chip 1 and the control substrate 2 is completed through the image acquisition unit 3 and the accurate alignment platform 5.
According to the laser eutectic welding method, a laser system is adopted to heat, melt and attach metal electrodes in contact with welding points, firstly, a quartz negative pressure adsorption device takes materials from a material placing box, Micro LEDs and control substrate position information are collected through a high-definition camera, and alignment is carried out through a high-precision alignment platform. After the alignment is finished, the high-precision alignment platform rises to enable the Micro LED and the control substrate to be attached together. And then, the laser system works to heat the welding point, and finally the Micro LED and the control substrate are pasted, welded together.
Claims (10)
1. A laser eutectic welding device for a micro LED chip and a control substrate is characterized in that a plurality of LED wafers in the micro LED chip (1) and the control substrate (2) are welded together by laser;
the micro LED chip (1) comprises a chip substrate (15) and a plurality of LED wafers (11) fixed on the chip substrate (15); the plurality of LED chips (11) are provided with a common first negative electrode (12), and the plurality of LED chips (11) are respectively provided with an independent first positive electrode (13);
the control substrate (2) is positioned below the micro LED chip (1) and comprises a control substrate main body (21) and a plurality of second positive electrodes (22) and a second negative electrode (23) which are positioned on the control substrate main body (21);
the laser eutectic welding device includes:
a negative pressure adsorption unit (4) for adsorbing the micro LED chip (1) and placing it on the control substrate (2);
and the laser emitting system (6) is positioned above the micro LED chip (1) and is used for heating welding points of the first positive electrodes (13), the second positive electrodes (22) and the first negative electrodes (12) and the second negative electrodes (23) by emitting laser to complete simultaneous eutectic welding.
2. Laser eutectic soldering device of micro LED chips according to claim 1, characterized in that the number of second positive electrodes (22) is equal to the number of first positive electrodes (13); the positions of the first positive electrode (13) and the second positive electrode (22) correspond, and the precision deviation is less than 0.7 mu m; the first negative electrode (12) and the second negative electrode (23) are both one and planar, and the plurality of LED chips (11) are electrically connected to the control substrate (2) in a manner of sharing a cathode.
3. The laser eutectic welding device of claim 1, characterized in that, the laser eutectic welding device further comprises an image acquisition unit (3) for acquiring images of the micro LED chip (1) and the control substrate (2), the image acquisition unit (3) is connected with an external host computer and can send the acquired images to the external host computer; the image acquisition unit (3) comprises a plurality of CCD cameras.
4. The laser eutectic welding device of claim 1, characterized in that the negative pressure adsorption unit (4) comprises a negative pressure adsorption unit body (41), an air extraction opening (42) and a negative pressure adsorption hole (43), wherein an air extraction device is connected to the air extraction opening (42) to extract air in the negative pressure adsorption unit body (41), so that the negative pressure adsorption hole (43) is in a negative pressure environment, thereby generating a suction force to absorb the micro LED chip (1).
5. The laser eutectic soldering device of claim 4, wherein the negative pressure suction unit body (41) is transparent and is selected from transparent materials such as quartz and glass; the negative pressure adsorption holes (43) are distributed on the periphery outside the display area of the chip substrate (15) and avoid the positions of the alignment target points, and the occupied area is smaller than that of the chip substrate (15).
6. Laser eutectic soldering device according to claim 1, characterized in that the chip substrate (15) further has a first alignment target (14) thereon, the control substrate body (21) has a second alignment target (24) thereon; the first alignment target (14) and the second alignment target (24) are matched, so that the micro LED chip (1) corresponds to the control substrate (2), the first positive electrode (13) is electrically connected with the second positive electrode (22), and the first negative electrode (12) is electrically connected with the second negative electrode (23).
7. The laser eutectic welding device of claim 6, characterized in that the first alignment target (14) is a small square, and the second alignment target (24) is four separate small squares, wherein the four separate small squares are two by two juxtaposed to form a large square with a cross shape in the middle, the four separate small squares are respectively located at the four corners of the large square, and the small square of the first alignment target (14) can just fit into the cross point of the cross shape and is equal to the gap between the small squares of each of the second alignment targets (24) at the periphery.
8. The laser eutectic welding device according to claim 1, characterized in that the laser eutectic welding device further comprises a precise alignment platform (5), wherein the precise alignment platform (5) can control the control substrate (2) to move to be aligned at X, Y, Z in theta axis;
the accurate alignment platform (5) is also connected with an external computer host, the micro LED chip (1) and the control substrate (2) are enabled to correspond in position through the first alignment target (14) and the second alignment target (24), the image acquisition unit (3) acquires images of the first alignment target (14) and the second alignment target (24) and feeds back image information to the external computer host, and the computer host further adjusts the positions of the first alignment target (14) and the second alignment target (24) by regulating and controlling the accurate alignment platform (5) according to the image information and a set value.
9. A laser eutectic welding method for a micro LED chip and a control substrate is characterized in that the laser eutectic welding device of any one of claims 1 to 8 is used, and the method comprises the following steps:
A. the negative pressure adsorption unit (4) adsorbs the micro LED chip (1) and places the micro LED chip on the control substrate (2);
B. the micro LED chip (1) and the control substrate (2) are aligned and attached together;
C. the laser eutectic welding system (6) works to heat the welding point and finish welding.
10. The laser eutectic soldering method of a micro LED chip and a control substrate according to claim 9, wherein the alignment of the micro LED chip (1) and the control substrate (2) is completed by an image acquisition unit (3) and a precise alignment platform (5).
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| CN2021105185216 | 2021-05-12 | ||
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114023862A (en) * | 2021-10-29 | 2022-02-08 | 厦门天马微电子有限公司 | Micro-LED substrate and preparation method and application thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114023862A (en) * | 2021-10-29 | 2022-02-08 | 厦门天马微电子有限公司 | Micro-LED substrate and preparation method and application thereof |
| CN114023862B (en) * | 2021-10-29 | 2022-08-30 | 厦门天马微电子有限公司 | Micro-LED substrate and preparation method and application thereof |
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