CN115241355A - Chip transfer method and device and display backboard - Google Patents

Chip transfer method and device and display backboard Download PDF

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Publication number
CN115241355A
CN115241355A CN202110444465.6A CN202110444465A CN115241355A CN 115241355 A CN115241355 A CN 115241355A CN 202110444465 A CN202110444465 A CN 202110444465A CN 115241355 A CN115241355 A CN 115241355A
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Prior art keywords
chip
bonding pad
transfer
bonding
substrate
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李强
汪楷伦
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Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
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Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
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Priority to CN202110444465.6A priority Critical patent/CN115241355A/en
Publication of CN115241355A publication Critical patent/CN115241355A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
    • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68372—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used to support a device or wafer when forming electrical connections thereto
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/812—Applying energy for connecting
    • H01L2224/81201—Compression bonding
    • H01L2224/81205—Ultrasonic bonding
    • 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

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Die Bonding (AREA)

Abstract

The invention relates to a chip transfer method, a device and a display back plate.A first bonding pad of a chip is butted with a corresponding second bonding pad on a circuit substrate in the transfer process of the chip, and then the first bonding pad and the second bonding pad are bonded by high-frequency mechanical vibration and pressure applied to the butted first bonding pad and the butted second bonding pad, so that the situation that the first bonding pad of the chip transferred before and the corresponding second bonding pad on the circuit substrate are separated due to non-bonding in the transfer process of subsequent batches of chips is avoided, and the bonding yield in the chip transfer process is improved; and the circuit substrate is not required to be heated at high temperature in the chip transferring process, so that various adverse effects caused by the high-temperature heating of the circuit substrate can be avoided, the reliability of the circuit substrate is improved, and the service life of the circuit substrate can be prolonged.

Description

Chip transfer method and device and display backboard
Technical Field
The invention relates to the technical field of chip transfer, in particular to a chip transfer method and device and a display back plate.
Background
Micro LEDs are called next generation display devices because of their advantages such as high brightness, wide color gamut coverage, and high contrast, and their popularity has been increasing in recent years; however, in the actual production process, there are many problems to be overcome, such as chip yield improvement, bulk transfer, bulk detection and repair, etc.;
in the related technology, a hot-press bonding mode is mostly used, an electrode pad of the Micro LED chip is contacted with a metal pad on the display substrate which is heated to a melting state at a high temperature, and after the display substrate is cooled, the metal pad on the Micro LED chip is changed from the melting state to a solidification state, and then the bonding of the electrode pad and the metal pad is completed.
The LED chip transfer can be completed through multiple batches, so that the whole surface of the display substrate needs to be heated at high temperature in the LED chip transfer process to enable the metal bonding pad on the display substrate to be kept in a molten state; when the chips in the current batch are transferred, the electrode bonding pads of the Micro LED chips which are transferred before are only contacted with the metal bonding pads in the melting state on the display substrate and are not fixed, namely bonding is not finished, so that the electrode bonding pads of the Micro LED chips which are transferred before are easily separated from the metal bonding pads on the circuit board in the transferring process of the LED chips at the back, and the yield is low; and after the multiple batches of LED chips are transferred and heated at high temperature, the display substrate is easily affected by heat, so that the reliability and the service life of the display substrate are influenced.
Therefore, how to improve the bonding yield in the chip transfer process and avoid heating the display substrate at high temperature is an urgent problem to be solved.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, an object of the present invention is to provide a chip transferring method, a chip transferring apparatus and a display backplane, which aim to solve the problems of low yield of bonding during chip transferring and high temperature heating of a display substrate in the related art.
A chip transfer apparatus, comprising:
the bearing table is configured to bear a circuit substrate, a chip bonding area is arranged on the circuit substrate, a second bonding pad corresponding to a first bonding pad on a chip is arranged in the chip bonding area, and when the circuit substrate is borne on the bearing table, the second bonding pad is far away from one surface of the bearing table, which is in contact with the circuit substrate;
a transfer head configured to pick up a chip from a transfer substrate, a first pad of the chip picked up by the transfer head, a side away from the chip in contact with the transfer head;
the motion control platform is configured to drive the transfer head and/or the bearing table to move so as to butt a first bonding pad of a chip picked up by the transfer head with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and generate relative pressure between the butted first bonding pad and the second bonding pad;
a vibration control platform configured to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the chip picked by the transfer head and/or the circuit substrate carried by the bearing platform, so that the first bonding pad and the second bonding pad which are butted are bonded under the high-frequency mechanical vibration and the pressure.
After a chip is picked up from a transfer substrate by a transfer head of the chip transfer device, the motion control platform drives the transfer head and/or a bearing platform of the chip transfer device to move so as to butt a first bonding pad of the chip picked up by the transfer head with a corresponding second bonding pad on a circuit substrate on the bearing platform and generate relative pressure between the butted first bonding pad and the second bonding pad; under the high-frequency mechanical vibration generated by a vibration control platform of the chip transfer device and acting on a chip picked by the transfer head and/or a circuit substrate borne by the bearing table, the butted first bonding pad and second bonding pad are bonded under the high-frequency mechanical vibration and pressure, so that the condition that the first bonding pad of the chip transferred before and the corresponding second bonding pad on the circuit substrate are separated due to non-bonding in the subsequent chip transfer process is avoided, and the bonding yield in the chip transfer process is improved; and because the second bonding pad on the circuit substrate is not required to be melted by heating the circuit substrate at high temperature, various adverse effects caused by heating the circuit substrate at high temperature can be avoided, the reliability of the circuit substrate is improved, and the service life of the circuit substrate is prolonged.
Based on the same inventive concept, the invention also provides a chip transfer method, which comprises the following steps:
arranging a circuit substrate on the bearing table of the chip transfer device;
picking up a chip from a transfer substrate by the transfer head;
controlling the transfer head and/or the bearing table to move so as to butt a first bonding pad of a chip picked up by the transfer head with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and generating relative pressure between the butted first bonding pad and the butted second bonding pad;
and controlling the vibration control platform to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on a chip picked by the transfer head and/or a circuit substrate carried by the bearing table, so that the butted first bonding pad and second bonding pad are bonded under the high-frequency mechanical vibration and the pressure.
According to the chip transfer method, after the first bonding pad of the chip picked up by the transfer head is butted with the corresponding second bonding pad on the circuit substrate, bonding is completed under the action of high-frequency mechanical vibration and pressure acting on the butted first bonding pad and the butted second bonding pad, namely the first bonding pad of each batch of transferred chips can be bonded with the corresponding second bonding pad on the circuit substrate in the batch transfer process, the situation that the first bonding pad of the previously transferred chip and the corresponding second bonding pad on the circuit substrate are separated due to non-bonding in the subsequent batch of chip transfer process is avoided, and the bonding yield in the chip transfer process is improved; and the high-temperature heating of the circuit substrate is not needed in the chip transfer process, so that various adverse effects caused by the high-temperature heating of the circuit substrate can be avoided, the reliability of the circuit substrate is improved, and the service life of the circuit substrate can be prolonged.
Based on the same inventive concept, the invention also provides a display back plate, which comprises a display substrate provided with a plurality of chip bonding areas and micro LED chips arranged in the chip bonding areas, wherein the micro LED chips are transferred to the chip bonding areas by the chip transfer method. Therefore, the display back plate is higher in yield, better in reliability and longer in service life.
Drawings
Fig. 1 is a first schematic structural diagram of a chip transfer device according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a chip transfer device according to a second embodiment of the present invention;
fig. 3 is a schematic structural diagram of a chip transfer device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a chip transfer device according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a chip transfer device according to a fifth embodiment of the present invention;
fig. 6 is a sixth schematic structural view of a chip transfer device according to an embodiment of the present invention;
fig. 7 is a seventh schematic structural diagram of a chip transfer device according to an embodiment of the present invention;
FIG. 8 is a first flowchart illustrating a chip transfer method according to an embodiment of the present invention;
FIG. 9 is a schematic diagram illustrating a chip repair process according to an embodiment of the present invention;
FIG. 10-1 is a schematic view of a Micro LED chip on a growth substrate according to an embodiment of the present invention;
FIG. 10-2 is a schematic view illustrating a bonding process between a growth substrate and a transfer substrate according to an embodiment of the present invention;
FIG. 10-3 is a schematic illustration of the lift-off of a growth substrate according to an embodiment of the present invention;
FIG. 10-4 is a schematic diagram of a growth substrate provided in an embodiment of the present invention after being peeled;
FIGS. 10-5 are schematic diagrams of display substrates according to embodiments of the present invention;
FIG. 11-1 is a schematic view of a mounting structure of a transfer head according to an embodiment of the present invention;
FIG. 11-2 is a schematic view of an installation configuration for a first horn provided by an embodiment of the present invention;
fig. 11-3 is a schematic structural view of a mounting fixture according to an embodiment of the present invention;
fig. 11-4 are schematic structural views of the installation jig plugged into the expansion hole according to the embodiment of the present invention;
fig. 11-5 are schematic views illustrating an expanded state of the mounting jig provided in the embodiment of the present invention after the mounting jig is rotated in the expansion hole;
fig. 12-1 is a schematic structural view of a transfer substrate carried by a carrier stage according to an embodiment of the invention;
fig. 12-2 is a schematic structural view illustrating a bonding structure between a transfer head and a transfer substrate according to an embodiment of the present invention;
fig. 12-3 is a schematic structural diagram of a transfer head picking up a chip from a transfer substrate according to an embodiment of the present invention;
fig. 12-4 are schematic structural diagrams of a display substrate carried by a carrier stage according to an embodiment of the invention;
fig. 12-5 are schematic structural diagrams illustrating alignment between a transfer head and a display substrate according to an embodiment of the invention;
fig. 12-6 are schematic structural diagrams illustrating a bonding structure between a transfer head and a display substrate according to an embodiment of the invention;
fig. 12-7 are schematic diagrams illustrating a bonding structure of a first pad and a second pad according to an embodiment of the present invention;
FIGS. 12-8 are schematic views of a transfer head according to an embodiment of the present invention away from a display substrate;
FIG. 13 is a second flowchart illustrating a chip transfer method according to an embodiment of the present invention;
description of the reference numerals:
1-a bearing platform, 2-a transfer head, 21-a connecting rod, 211-a connecting end, 31-a first electric signal generator, 32-a first transducer, 33-a first amplitude transformer, 331-an expansion hole, 332-a mounting hole, 35-a second electric signal generator, 36-a second transducer, 37-a second amplitude transformer, 41-X-Y axis moving platform, 42-Z axis moving platform, 51-an energy conversion part, 61-a growth substrate, 62-a Micro LED chip, 621-a first bonding pad, 63-a pyrolytic glue layer, 64-a transfer substrate, 71-a circuit substrate, 72-a second bonding pad, 73-a conductive channel layer, 8-a mounting jig and 81-a mounting end.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all 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. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
In the related art, when the LED chip is transferred, the entire surface of the display substrate needs to be heated at a high temperature so that the metal pad on the display substrate is kept in a molten state; because the electrode pad of the Micro LED chip which is transferred before is only contacted with the metal pad in a melting state on the display substrate and is not fixed, in the subsequent LED chip transferring process, the electrode pad of the Micro LED chip which is transferred before is easy to be separated from the metal pad on the circuit board, so that the yield is low; and after the multiple batches of LED chips are transferred and heated at high temperature, the display substrate is easily influenced by heat, and the reliability and the service life of the display substrate are influenced.
Based on this, the present invention intends to provide a solution to the above technical problem, the details of which will be explained in the following embodiments.
The embodiment provides a chip transfer device, which can be used for transferring chips, and the chips can include various semiconductor chips, such as light emitting chips (for example, LED chips, which can include common-sized LED chips, micro LED chips, mini LED chips), driving chips, control chips, resistance chips, capacitance chips, and the like. The transfer device can be used for transferring a single chip or a small number of chips and can also be used for transferring a large number of chips in batches.
The chip transfer device that this embodiment provided includes plummer, transfer head, motion control platform and vibration control platform, wherein:
and a carrier stage configured to carry the circuit substrate. The circuit substrate is provided with a chip bonding area, a second bonding pad corresponding to the first bonding pad on the chip is arranged in the chip bonding area, and when the circuit substrate is borne on the bearing platform, the second bonding pad is far away from one surface of the bearing platform, which is contacted with the circuit substrate, so as to be butted with the first bonding pad of the chip to be transferred; it should be understood that the circuit substrate in this embodiment can be flexibly configured according to a specific application scenario, for example, when the transferred chip is a light emitting chip, the circuit substrate can be, but is not limited to, a display substrate in a display field (the display substrate can be applied to, but is not limited to, a television, a display, a mobile terminal, a wearable device, an advertisement screen, and a sign), a lamp panel in a lighting field (the lamp panel can be applied to, but is not limited to, a household lighting field, a medical lighting field, a decoration field, an automobile field, and a traffic field).
A transfer head configured to pick up a chip from a transfer substrate, a first pad of the chip picked up by the transfer head being away from a face of the chip in contact with the transfer head so as to be opposed to a second pad; the transfer head in this embodiment can pick up the chip from the transfer substrate by, but not limited to, magnetic force, electrostatic, vacuum, or other absorption means; the transfer head in this embodiment can pick up one chip at a time from the transfer substrate, and can also pick up two or more chips (i.e., multiple chips) as required; the transfer substrate in this embodiment may be a growth substrate for a chip, or may be a transient substrate for carrying a chip transferred from the growth substrate.
And the motion control platform is configured to drive the transfer head and/or the bearing platform to move so as to butt a first bonding pad of the chip picked up by the transfer head with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and generate relative pressure between the butted first bonding pad and the butted second bonding pad. The motion control platform in this embodiment may drive at least one of the transfer head and the carrier stage to move and/or rotate in a direction beyond a corresponding direction, so that the first pad of the chip picked up by the transfer head is butted with the second pad in the corresponding chip bonding region on the circuit substrate (i.e., the first pad is in relative contact with the corresponding second pad), and after the first pad is butted with the second pad, at least one of the transfer head and the carrier stage is driven to move beyond the other side, so that a relative pressure is generated between the first pad and the second pad. For example, the transfer head may be controlled to move towards the carrier so that the first bonding pad of the chip picked up by the transfer head generates a pressure towards the corresponding second bonding pad of the circuit board, or the carrier may be controlled to move towards the transfer head so that the second bonding pad of the circuit board generates a pressure towards the first bonding pad of the chip picked up by the transfer head, or both the transfer head and the carrier may be controlled to move towards each other. And it should be understood that the pressure generated in this embodiment is sufficient to meet the bonding requirements of the first and second pads, and will not damage the first pad (or chip) and the second pad (or circuit substrate). For ease of understanding, the present embodiment exemplifies a specific motion control manner in the subsequent section.
And the vibration control platform is configured to generate high-frequency mechanical vibration, and the high-frequency mechanical vibration acts on the chip picked up by the transfer head and/or the circuit substrate carried by the bearing platform, so that the butted first bonding pad and second bonding pad are bonded under the high-frequency mechanical vibration and pressure. Because the first bonding pad and the second bonding pad are made of conductive materials, the bonding of the first bonding pad and the second bonding pad is essentially that under the action of pressure and high-frequency mechanical vibration, electron sharing and atomic diffusion are generated in the close contact of the first bonding pad and the second bonding pad, and then a conductive channel layer is formed to realize bonding. For example, when one of the first bonding pad and the second bonding pad comprises gold and the other comprises aluminum, under the action of pressure and high-frequency mechanical vibration, the first bonding pad and the second bonding pad generate electron sharing and atom diffusion in close contact with each other, and then an intermetallic compound layer, namely a conductive channel layer, is formed to realize bonding.
In addition, in the embodiment, when the oxide layer film is generated on the surface of the first pad and/or the second pad, the oxide layer film can be broken through high-frequency mechanical vibration, so that the success rate of bonding the first pad and the second pad can be improved.
The high-frequency mechanical vibration in the present embodiment refers to a mechanical vibration having a vibration frequency of 10KHZ or more, for example, the vibration frequency may be 10KHZ to 45 KHZ. And it should be understood that the vibration amplitude of the mechanical vibration in the present embodiment can be flexibly set, and the vibration amplitude is set so that the first bonding pad and the second bonding pad can be bonded without causing damage to the first bonding pad (or the chip) and the second bonding pad (or the circuit substrate).
It can be seen that, after the chip transfer device provided by this embodiment picks up a chip from a transfer substrate by using its transfer head, the motion control platform of the chip transfer device can drive the transfer head and/or the carrier of the chip transfer device to move, so as to butt-joint a first pad of the chip picked up by the transfer head with a corresponding second pad on a circuit substrate on the carrier, and generate a relative pressure between the butted first pad and second pad, and under the high-frequency mechanical vibration generated by the vibration control platform and acting on the chip picked up by the transfer head and/or the circuit substrate carried by the carrier, the butted first pad and second pad are bonded, and the circuit substrate does not need to be heated at high temperature, thereby avoiding various adverse effects on the circuit substrate caused by high-temperature heating; and in the subsequent chip transfer process, the first bonding pad of the chip transferred before and the corresponding second bonding pad on the circuit substrate are prevented from being separated due to non-bonding, and the bonding yield in the chip transfer process is improved.
In the present embodiment, the vibration control platform of the chip transfer apparatus may include at least one of a first vibration generating part and a second vibration generating part; wherein the first high-frequency mechanical vibration generated by the first vibration generating part acts on the transfer head so as to act on the chip picked up by the transfer head; the second high-frequency mechanical vibration generated by the second vibration generating component acts on the bearing table, thereby acting on the circuit substrate borne by the bearing table. That is, in the present embodiment, in order to bond the first pad and the second pad, only the first high-frequency mechanical vibration acting on the transfer head or only the second high-frequency mechanical vibration acting on the carrier stage may be generated according to the requirement, and the first high-frequency mechanical vibration acting on the transfer head and the second high-frequency mechanical vibration acting on the carrier stage may also be generated respectively according to the requirement. For ease of understanding, several examples of the arrangement are illustrated below.
Vibration control platform setup example one:
referring to fig. 1, the chip transfer apparatus includes a stage 1, a transfer head 2, and a first vibration generating member. Wherein the first vibration generating component comprises a first electric signal generator 31, a first transducer 32 and a first amplitude transformer 33, the first amplitude transformer 33 is positioned between the first transducer 32 and the transfer head 2, the first electric signal generator 31 is configured to generate a first high-frequency electric signal, the first transducer 32 is configured to convert the first high-frequency electric signal output by the first electric signal generator 31 into first high-frequency mechanical vibration, and the first amplitude transformer 33 is configured to amplify and transmit the amplitude of the first high-frequency mechanical vibration generated by the first transducer 32 to the transfer head so as to act on a chip picked up by the transfer head. The first electrical signal generator 31 in this example may be, but is not limited to, a first power source/ultrasonic controller configured to convert 50HZ electrical energy into 10KHZ to 45KHZ first high frequency electrical signals, for example, 10KHZ, 15KHZ, 20KHZ, 25KHZ, 30KHZ, 40KHZ or 45KHZ first high frequency electrical signals. In this example, the first vibration generating component may be controlled to generate the first high-frequency mechanical vibration only after the first pad of the chip captured by the transfer head is butted with the corresponding second pad on the circuit substrate, and the first vibration generating component may be turned off after the butted first pad and second pad are bonded; the first vibration generating part can be turned on all the time during each chip transfer process or during the whole chip transfer process according to the requirement to generate the first high-frequency mechanical vibration.
In this example, the transfer head 2 may be fixedly connected to one end of the first horn 33, or may be closely attached and not fixedly connected to the first horn, so that at least the first high-frequency mechanical vibration energy is transmitted to the transfer head 2.
Example two vibration control platform settings:
referring to fig. 2, the chip transfer apparatus includes a carrier 1, a transfer head 2, and a second vibration generating member. Wherein the second vibration generating component comprises a second electrical signal generator 35, a second transducer 36 and a second amplitude transformer 37, the second amplitude transformer 37 is positioned between the second transducer 36 and the carrier table 1, the second electrical signal generator 35 is configured to generate a second high-frequency electrical signal, the second transducer 36 is configured to convert the second high-frequency electrical signal output by the second electrical signal generator 35 into a second high-frequency mechanical vibration, and the second amplitude transformer 37 is configured to amplify and transmit the amplitude of the second high-frequency mechanical vibration generated by the second transducer 36 to the carrier table, so as to act on the circuit substrate carried by the carrier table. The second electrical signal generator 35 in this example may be, but is not limited to, a second power source/ultrasonic controller configured to convert 50HZ electrical energy into 10KHZ to 45KHZ second high frequency electrical signals, for example, 10KHZ, 18KHZ, 20KHZ, 26KHZ, 30KHZ, 40KHZ or 45KHZ second high frequency electrical signals. In this example, the second vibration generating component may be controlled to generate the second high-frequency mechanical vibration only after the first pad of the chip captured by the transfer head is butted with the corresponding second pad on the circuit substrate, and the second vibration generating component may be turned off after the butted first pad is bonded with the second pad; the second vibration generating part can be turned on all the time during each chip transfer process or during the whole chip transfer process according to the requirement to generate the second high-frequency mechanical vibration.
In this example, the carrier table 1 may be fixedly connected to the second horn 37, or may be tightly attached and not fixedly connected to the second horn, so as to ensure that at least the second high-frequency mechanical vibration energy is transmitted to the carrier table 1.
Example three vibration control platform settings:
referring to fig. 3, the chip transfer apparatus includes a first vibration generating member and a second vibration generating member, which are opposite to the chip transfer apparatus shown in fig. 1 and 2. In this example, only one of the first vibration generating means and the second vibration generating means may be controlled to be activated to produce the first high-frequency mechanical vibration or the second high-frequency mechanical vibration as required; the first vibration generating means and the second vibration generating means may also be controlled to be both activated to generate the first high frequency mechanical vibrations and the second high frequency mechanical vibrations as required.
In this example, when both the first vibration generating means and the second vibration generating means are controlled to be activated, at least one of the phases and frequencies of the first high-frequency electrical signal generated by the first electrical signal generator 31 and the first high-frequency electrical signal generated by the second electrical signal generator 35 may be controlled to be different, so as to improve the vibration effect of the first high-frequency mechanical vibration and the second high-frequency mechanical vibration, and further ensure the bonding quality of the first pad and the second pad.
In this example, the second vibration amplitude of the second high-frequency mechanical vibration may be set to be different from the first vibration amplitude of the first high-frequency mechanical vibration according to the requirement, and for example, the pseudo second vibration amplitude may be set to be larger than the first vibration amplitude.
It should be understood that the first electrical signal generator 31 and the second electrical signal generator 35 in this example may also multiplex one electrical signal generator in some application scenarios. The first transducer 32 and the second transducer 36 may also multiplex one transducer in some application scenarios.
In this embodiment, the motion control platform may drive the transfer head and/or the carrier stage to move in a corresponding direction, so as to butt a first bonding pad of a chip picked up by the transfer head against a second bonding pad in a corresponding chip bonding region on the circuit substrate, and generate a relative pressure between the butted first bonding pad and the second bonding pad. The motion control platform can control and drive the transfer head to move, can only control the bearing platform to move, and can also selectively control the transfer head and the bearing platform to move. And the mode of controlling the movement of the transfer head and/or the bearing table comprises moving and/or rotating, and the direction of controlling the movement of the transfer head and/or the bearing table can be flexibly set according to requirements. For the sake of easy understanding, the present embodiment will be described by taking as an example the case where the chip transfer device is located in a three-dimensional coordinate system. The motion control platform in this embodiment may include an X-Y axis moving platform for controlling the target object to move in the X axis or Y axis direction and a Z axis moving platform for controlling the target object to move in the Z axis direction, and may also include a rotation control platform for controlling the target object to rotate in the corresponding direction according to requirements. An example of the arrangement of the motion control platform shown in this embodiment is shown in fig. 1 to 6.
Referring to the three chip transferring devices shown in fig. 1 to fig. 3, the motion control platform includes a Z-axis moving platform 42 for driving the transferring head 2 to move along the Z-axis, and an X-Y-axis moving platform 41 for driving the carrier table 1 to move along the X-axis or the Y-axis, and the carrier table 1 can be controlled to move in the corresponding direction by the X-Y-axis moving platform 41, so that the chip bonding area on the circuit substrate on the carrier table 1 corresponds to the chip picked up by the transferring head 2 in position; the Z-axis moving platform 42 can control the moving of the transfer head 2 toward the direction close to the carrier 1, so that the first bonding pad of the chip picked up by the transfer head 2 is butted with the second bonding pad in the bonding pad of the corresponding chip on the circuit substrate, and after the two are butted, the trend that the transfer head 2 moves toward the direction close to the carrier 1 is continuously controlled, so that the first bonding pad generates a pressure toward the butted second bonding pad, and the pressure is a downward pressure in fig. 1-3.
Referring to fig. 4, the motion control platform of the chip transfer apparatus includes a Z-axis moving platform 42 for driving the carrier 1 to move along the Z-axis, and an X-Y-axis moving platform 41 for driving the transfer head 2 to move along the X-axis or the Y-axis, and the X-Y-axis moving platform 41 can control the movement of the transfer head 2 in the corresponding direction, so that the chip bonding area on the circuit substrate on the carrier 1 corresponds to the chip picked up by the transfer head 2 in position; the moving platform 42 can control the carrier 1 to move towards the direction close to the transfer head 2, so that the first bonding pad of the chip picked up by the transfer head 2 is butted with the second bonding pad in the bonding area of the corresponding chip on the circuit substrate, and the trend that the carrier 1 moves towards the direction close to the transfer head 2 is continuously controlled after the two are butted, so that the second bonding pad generates a pressure towards the butted first bonding pad. In fig. 4 the pressure is one directed upwards.
Referring to fig. 5, the motion control platform of the chip transfer apparatus includes a Z-axis moving platform 42 for driving the transfer head 2 to move along the Z-axis, and an X-Y-axis moving platform 41 for driving the transfer head 2 to move along the X-axis or the Y-axis, and the X-Y-axis moving platform 41 can control the movement of the transfer head 2 in the corresponding direction, so that the chip bonding area on the circuit substrate on the carrier table 1 corresponds to the chip picked up by the transfer head 2 in position; the Z-axis moving platform 42 can control the transfer head 2 to move towards the direction close to the bearing table 1, so that a first bonding pad of a chip picked up by the transfer head 2 is butted with a second bonding pad in a corresponding chip bonding area on the circuit substrate, and the trend that the transfer head 2 moves towards the direction close to the bearing table 1 is continuously controlled after the two are butted, so that the first bonding pad generates downward pressure towards the butted second bonding pad. In this example, the carrier table 1 can remain stationary during the chip transfer process.
Referring to fig. 6, the motion control platform of the chip transferring apparatus includes a Z-axis moving platform 42 for driving the carrier 1 to move along the Z-axis, and an X-Y-axis moving platform 41 for driving the carrier 1 to move along the X-axis or the Y-axis, and the carrier 1 is controlled by the X-Y-axis moving platform 41 to move in the corresponding direction, so that the chip bonding area on the circuit substrate on the carrier 1 corresponds to the chip picked up by the transferring head 2 in position; the moving platform 42 can control the carrier 1 to move towards the direction close to the transfer head 2, so that the first bonding pad of the chip picked up by the transfer head 2 is butted with the second bonding pad in the corresponding chip bonding area on the circuit substrate, and the trend that the carrier 1 moves towards the direction close to the transfer head 2 is continuously controlled after the two are butted, so that the second bonding pad generates an upward pressure towards the butted first bonding pad. In this example, the transfer head 2 may remain stationary after picking up a chip from the transfer substrate and reaching the set position.
Of course, it should be understood that the chip transfer arrangement in each of the above examples may further include a rotation control platform for controlling at least one of the transfer head 2 and the carrier table 1 to rotate in a predetermined direction, so that the first bonding pad and the second bonding pad are also aligned angularly when they are butted. Moreover, the above examples are only examples for easy understanding, and on this basis, other alternative combinations may be adopted according to the requirement, for example, the transfer head 2 and the carrier table 1 may be controlled to move along the X axis or the Y axis, or the transfer head 2 and the carrier table 1 may be controlled to move along the Z axis, and so on, which are not described herein again.
Another alternative embodiment:
the chip transfer device provided by the embodiment may further include a heating platform configured to heat the circuit substrate on the carrier table to a first temperature range, so as to promote atomic diffusion at the bonding interface of the butted first bonding pad and second bonding pad, and improve bonding efficiency and quality. The first temperature range in this embodiment is a low temperature range, and a maximum temperature value in the first temperature range is smaller than a first temperature critical value for melting the first pad and smaller than a second temperature critical value for melting the second pad. For example, the first temperature range may be, but not limited to, 70 ℃ to 150 ℃, and may be specifically set to 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, or 150 ℃.
In one example of this embodiment, the heating platform may heat the circuit substrate on the carrier by, but not limited to, converting electrical energy into thermal energy. In this example, the heating platform includes an energy conversion device for converting electrical energy into thermal energy, and the energy conversion device may be disposed on the susceptor or may not be disposed on the susceptor. In some application scenarios, when the energy conversion member is disposed on the plummer, the energy conversion member may be embedded in the plummer. For example, referring to the chip transfer device illustrated in fig. 1 to 6, the energy conversion element 51 may be embedded in the carrier 1 to improve the integration and simplify the structure of the device, and the carrier 1 has heat transfer characteristics. Of course, the energy conversion member may also be directly disposed on the surface of the carrier 1, for example, referring to the chip transferring device shown in fig. 7, the energy conversion member 51 is disposed on the upper surface of the carrier 1, and the circuit substrate may be directly disposed on the energy conversion member 51, so as to improve the heating efficiency and the energy utilization rate. Of course, in other application examples, a portion of the energy conversion member 51 may be exposed from the carrier, and a portion may be embedded in the carrier. The specific setting mode and the specific shape and size of the energy conversion member can be flexibly set, and are not described herein again.
In another example of the present embodiment, the carrier stage may be further configured to carry the transfer substrate. That is, in the present example, the carrier table may be used to carry the transfer substrate and the circuit substrate. It should be understood that the transfer substrate may be disposed at other positions instead of on the susceptor, and will not be described herein.
In this example, the heating platform may be further configured to heat the transfer substrate on the carrier table to a second temperature range, the second temperature range being a low temperature range, a maximum temperature value in the second temperature range being less than the first temperature threshold value and the second temperature threshold value. The second temperature range may be the same as or different from the first temperature range. For example, the value of the second temperature range may be, but is not limited to, 80 ℃ to 100 ℃, and may be specifically set to 80 ℃, 90 ℃, or 100 ℃ or the like; or the second temperature range is also 70 ℃ to 150 ℃. The heating platform heats the transfer substrate on the bearing table to a second temperature range, so that the first bonding pad on the chip is preheated to a certain temperature before being picked up by the transfer head, the bonding of the first bonding pad and the corresponding second bonding pad in the subsequent chip transfer process can be further promoted, and the bonding efficiency and quality are improved. And when the chip is fixed on the transfer substrate through the pyrolytic glue, the heating can be used for debonding, so that the situation that a heating device is independently arranged to debond the transfer substrate is avoided, the transfer process is further simplified, the transfer efficiency is improved, and the transfer cost is reduced.
Of course, it should be understood that, in some application examples of the present embodiment, the heating platform may not heat the transfer substrate.
In yet another example of this embodiment, the heating platform may be further configured to heat the circuit substrate on the carrier to a third temperature range after the second pad in each chip bonding region of the circuit substrate is bonded to the corresponding first pad of each chip, where the third temperature range is a high temperature range, and a minimum temperature value in the third temperature range is greater than or equal to the first temperature critical value and/or the second temperature critical value, so as to melt the first pad and/or the second pad, and thus after the first pad and/or the second pad is changed from a high-temperature melting state to a low-temperature curing state, the bonding quality between the bonded first pad and the bonded second pad may be further improved. And because only one-time high-temperature heating is needed to be carried out on the circuit substrate, the influence on the high-temperature heating of the circuit substrate can be reduced to the minimum.
According to the chip transfer device provided by the embodiment, after the first bonding pad of the chip is butted with the second bonding pad in the corresponding chip bonding area on the circuit substrate, under the pressure and high-frequency mechanical vibration acting between the first bonding pad and the second bonding pad, at least one of the first bonding pad and the second bonding pad of the heating platform can be heated to promote the bonding between the first bonding pad and the second bonding pad, so that the bonding efficiency and the bonding quality can be further improved.
Another alternative embodiment:
the present embodiment provides a chip transferring method of the chip transferring apparatus in the above examples, which is shown in fig. 8 and includes but is not limited to:
s801: the circuit substrate is arranged on the bearing table.
It should be understood that, in the embodiment, when the carrier stage is also configured to carry the circuit substrate, the circuit substrate may be disposed on the carrier stage, and may be disposed simultaneously with the circuit substrate, prior to the circuit substrate, or later than the circuit substrate.
S802: the chip is picked up from the transfer substrate by the transfer head.
The transfer head in this step can pick up the chip from the transfer substrate by, but not limited to, at least one of magnetic force, electrostatic, vacuum adsorption.
S803: and controlling the movement of the transfer head and/or the bearing platform so as to butt a first bonding pad of the chip picked up by the transfer head with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and generating relative pressure between the butted first bonding pad and the butted second bonding pad.
As shown in the above examples, in this embodiment, at least one of the transfer head and the carrier stage can be controlled to move in a direction beyond the corresponding direction, so that the first pad of the chip picked up by the transfer head is butted with the second pad in the corresponding chip bonding region on the circuit substrate, and a relative pressure is generated between the butted first pad and the butted second pad, which is not described herein again.
S804: and controlling the vibration control platform to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the chip picked by the transfer head and/or the circuit substrate carried by the bearing table, so that the butted first bonding pad and second bonding pad are bonded under the high-frequency mechanical vibration and pressure.
As shown in the above examples, in this embodiment, the vibration control platform can be controlled to generate at least one of a first high-frequency vibration acting on the transfer head and a second high-frequency vibration acting on the carrier table, so that the butted first bonding pad and second bonding pad can be bonded under high-frequency mechanical vibration and pressure, which will not be described herein again.
In an example of this embodiment, in order to improve the efficiency and quality of bonding the first pad and the second pad, before the bonded first pad and the bonded second pad are subjected to high-frequency mechanical vibration and pressure, the method may further include: and controlling a heating platform of the chip transfer device to heat the circuit substrate on the bearing table to a first temperature range. For example, in an application scenario, the heating platform of the chip transfer device may be controlled to pre-heat the circuit substrate on the carrier table to a first temperature range before the chip is picked up from the transfer substrate by the transfer head, and may be maintained in the first temperature range during a subsequent chip transfer process.
In a further example of the present embodiment, when the carrier stage is configured to also carry the transfer substrate, before picking up the chip from the transfer substrate by the transfer head, the method further includes:
arranging the transfer substrate on the bearing table, and controlling a heating platform of the chip transfer device to heat the transfer substrate on the bearing table to a second temperature range before picking up the chip from the transfer substrate through the transfer head; the first bonding pad on the chip is preheated to a certain temperature before being picked up by the transfer head, so that bonding between the first bonding pad and the corresponding second bonding pad in the subsequent chip transfer process can be further promoted, and the bonding efficiency and quality are improved. And when the chip is fixed on the transfer substrate through the pyrolytic glue, the chip can be subjected to glue-releasing treatment through the heating, so that the situation that a heating device is independently arranged to perform glue-releasing treatment on the transfer substrate is avoided, the transfer process is further simplified, the transfer efficiency is improved, and the transfer cost is reduced.
In this embodiment, in a chip transferring process, after the vibration control platform is controlled to generate high-frequency mechanical vibration so that the first and second pads which are butted are bonded under the high-frequency mechanical vibration and pressure, when the transfer head is controlled to be away from the circuit substrate, the adsorption force generated when the transfer head keeps picking up the chip can be controlled to be away from the circuit substrate;
when the residual chip is adsorbed on the transfer head, the chip transfer process indicates that part of the chip is not successfully transferred, and a repairing process needs to be executed. In this embodiment, other conventional repairing processes may be used to repair the chip. The new repairing process provided by this embodiment can also be performed, and the repairing process is shown in fig. 9 and includes:
s901: and removing the residual chip on the transfer head and obtaining the corresponding target chip bonding area of the residual chip on the circuit substrate.
S902: chips of the same type as the remaining chips are picked up from the transfer substrate by the transfer head as supplementary chips.
In an application scenario, after the chip is transferred from the other chip bonding regions on the circuit substrate, the repairing process is performed, and before the chip with the same type as the residual chip is picked up from the transfer substrate by the transfer head as a supplementary chip, the chip transferring method further includes transferring the chip on the transfer substrate to the other chip bonding regions on the circuit substrate by the transfer head.
In another application scenario, after the repairing process is performed first, the next chip transfer may be performed by the above-mentioned chip transfer method.
S903: and controlling the movement of the transfer head and/or the bearing platform to butt the first bonding pad of the supplementary chip picked up by the transfer head with the second bonding pad in the bonding area of the target chip on the circuit substrate, and generating relative pressure between the butted first bonding pad and the butted second bonding pad.
S904: and controlling the vibration control platform to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the supplementary chip and/or the circuit substrate, so that the butted first bonding pad and second bonding pad are bonded under the high-frequency mechanical vibration and pressure.
In another example of this embodiment, in order to further improve the overall bonding quality and reliability, after the second bonding pad in each chip bonding region of the circuit substrate is bonded to the first bonding pad of the corresponding chip, that is, after the chip transfer is completed, the method may further include:
and controlling the heating platform to heat the circuit substrate on the bearing table to a third temperature range, so that the bonded first bonding pad and/or the bonded second bonding pad are/is melted, and thus, after the first bonding pad and/or the bonded second bonding pad are/is changed from a high-temperature melting state to a low-temperature curing state, the bonding quality between the bonded first bonding pad and the bonded second bonding pad can be further improved. And because only one-time high-temperature heating is needed to be carried out on the circuit substrate, the influence on the high-temperature heating of the circuit substrate can be reduced to the minimum.
Yet another alternative embodiment:
for convenience of understanding, the present embodiment is described by taking a specific application scenario as an example on the basis of the foregoing embodiments.
In this embodiment, the material of the first bonding pad of the chip includes gold, such as gold; the material of the second bonding pad on the circuit substrate includes aluminum, for example, aluminum. The chip is a flip-chip Micro LED chip, and the circuit substrate is a display substrate. The following description will be made by taking as an example a process from the growth of the Micro LED chip to the transfer onto the circuit substrate, as shown in fig. 13, including:
s1301: and growing the Micro LED chip on the growth substrate.
For example, referring to fig. 10-1, a Micro LED Chip 62 is prepared On a growth substrate 61 by, but not limited to, epitaxy, exposure, development, etching, deposition, and other processes, where the Micro LED Chip is generally called as COW (Chip On Wafer), and a first pad 621 of the Micro LED Chip is made of gold metal by evaporation; the first pad 621 includes an electrode pad and may further include other pads as needed.
S1302: and (3) attaching the Micro LED chip on the growth substrate to one surface of a transfer substrate (also called as a temporary storage substrate) provided with the pyrolytic adhesive layer.
The transfer substrate in this example may be, but is not limited to, a sapphire substrate with a pyrolytic glue film or a sapphire substrate coated with a pyrolytic glue solution; referring to fig. 10-2, the Micro LED chip 62 on the growth substrate 61 is attached to the surface of the transfer substrate 64 having the thermal decomposition adhesive layer 63. Of course, the pyrolytic glue layer can be replaced by a pyrolytic glue layer or other types of glue layers, which will not be described herein.
S1303: the growth substrate was peeled off, and the Micro LED chips were transferred onto a transfer substrate.
For example, the growth substrate may be peeled using, but not limited to, LLO (Laser Lift Off) technology, which is based on a specific wavelength (e.g., 266 nm) Laser to decompose gallium nitride between the growth substrate and the Micro LED chip into metal gallium and nitrogen gas, thereby peeling the growth substrate. Referring to fig. 10-3, in which the arrows indicate the laser irradiation direction, the growth substrate 61 may be peeled off so that the Micro LED chips 62 are transferred onto the transfer substrate 64, and the transferred state is shown in fig. 10-4.
S1304: the transfer substrate is placed on a stage of a chip transfer apparatus.
In this example, the chip transfer apparatus shown in fig. 1 is employed, and referring to fig. 12-1, the carrier stage 1 is configured to also carry the transfer substrate 64. In one application example, the transfer head 2 of the chip transfer device shown in fig. 1 is fixedly connected to the first horn 33. And it should be understood that the manner of fixedly connecting the transfer head 2 with the first horn 33 can be flexibly set, for example, but not limited to, clamping, sleeving, screwing, pinning, matching with threaded screw holes, and the like, and the connection can be detachable or non-detachable. For ease of understanding, a specific fastening method will be described as an example, and reference will be made to fig. 11-1 to 11-5. In fig. 11-1, the transfer head 2 is provided with a connecting rod 21, one end of which is connected to the transfer head 2 and the other end of which is connected to the first horn 33 as a connecting end 211, the connecting end 211 in this example being provided as a cylindrical fixed terminal. Referring to fig. 11-2, the first horn 33 is connected at one end to the first transducer 32 and at the other end is provided with an expansion hole 331 and a mounting hole 332. Referring to the mounting fixture 8 shown in fig. 11-3, which has a mounting end 81, the mounting end 81 in this example is provided as an oval head. Referring to fig. 11-4, when mounting, the mounting end 81 of the mounting jig 8 is plugged into the expanding hole 331, the mounting end 81 is an elliptical head, the expanding hole 331 is also not elliptical, and the short radius of the mounting end 81 and the expanding hole 331 are parallel when plugging; then, the mounting end 81 is rotated to make the long radius of the mounting end 81 gradually approach to the short radius of the expanding hole 331, so that the short radius component of the expanding hole 331 is expanded, when the long radius of the mounting end 81 and the short radius of the expanding hole 331 approach to be perpendicular, the short radius of the mounting hole 332 (also set as an elliptical hole in this example) is also driven to be expanded to the maximum, at this time, the connecting end 211 of the connecting rod 21 can be plugged into the mounting hole 332, then the mounting end 81 is rotated to make the short radius thereof approach to be parallel to the short radius of the expanding hole 331, and then the mounting end 81 is taken out from the expanding hole 331, in this process, the short radii of the expanding hole 331 and the mounting hole 332 are contracted, and finally, the short radius of the mounting hole 332 is contracted to form a tight connection with the connecting end 211.
S1305: and controlling the heating platform to preheat the transfer substrate on the bearing table, and then controlling the transfer head to pick up the Micro LED chip from the transfer substrate on the bearing table.
Referring to fig. 12-1, the transfer substrate 64 on the carrier table 1 is preheated to a second temperature range by controlling the heating platform, in this example, the heating temperature is set to 80 ℃, and when the glue is released, the first solder feet of the Micro LED chips on the transfer substrate 64 are also heated, so as to facilitate subsequent bonding. Referring to fig. 12-1 and 12-3, the operation control platform controls the transfer head 2 and the carrier table 1 such that the transfer head 2 approaches the transfer substrate 64 on the carrier table 1, and finally picks up the Micro LED chips from the transfer substrate 64. The number of Micro LED chips picked up by the transfer head 2 at one time may be flexibly set, and may be a single chip or multiple chips, as shown in fig. 12-3, in this example, multiple chips are picked up as an example for description.
S1306: and placing the display substrate on a bearing table.
Referring to fig. 10-5, a plurality of chip bonding regions are disposed on the display substrate 71, and a second bonding pad 72 corresponding to the first bonding pad of the Micro LED chip is disposed in each chip bonding region. Referring to fig. 12-4, the display substrate 71 is placed on the carrier table 1, and the display substrate 71 is heated by the heating platform to a first temperature range, which is also set to 80 ℃ in this example. It should be understood that, in this example, the display substrate 71 may be simultaneously placed on the carrier table 1 of the chip transfer device in S1304, and the transfer substrate 64 and the display substrate 71 may be simultaneously heated, thereby saving the preheating time and improving the transfer efficiency.
In this example, it is assumed that the second pad 72 on the display substrate 71 is made of aluminum metal by evaporation, and since aluminum metal is rapidly oxidized in air to form an aluminum oxide thin film with a thickness of nanometer order, the aluminum oxide thin film is dense to prevent further oxidation inside.
S1307: and controlling the movement of the transfer head and the bearing table so as to butt the first bonding pad of the Micro LED chip picked up by the transfer head with the corresponding second bonding pad on the display substrate, and generating relative pressure between the butted first bonding pad and the butted second bonding pad.
Referring to fig. 12-5, the first bonding pads of the Micro LED chips on the transfer head 2 are aligned with the corresponding second bonding pads on the display substrate 71 by the Z-axis moving stage 42 and the X-Y-axis moving stage 41. Referring to fig. 12-6, after the Z-axis moving platform 42 is controlled to make the corresponding first pad and second pad abut against each other, the transfer head 2 is kept pressed down, so that the first pad of the Micro LED chip on the transfer head 2 is pressed downward (i.e. toward the second pad abutting against the first pad), thereby making the first pad and the second pad abutting against each other have an interactive pressure.
S1308: and controlling the vibration control platform to generate first high-frequency mechanical vibration, wherein the first high-frequency mechanical vibration acts on the Micro LED chip picked by the transfer head, so that the first bonding pad and the second bonding pad which are butted are bonded under the high-frequency mechanical vibration and the pressure.
Referring to fig. 12-6, the butted first and second pads are bonded under the action of a pressure F and a first high frequency mechanical vibration Z.
The nature of the bonding of the first pad and the second pad, which in this example are made of gold metal and the second pad on the display substrate is made of aluminum metal, is such that electron sharing and atomic diffusion at the bonding interface (gold-aluminum) in intimate contact produces intermetallic compounds (IMC) to form a conductive channel layer 73 as shown in fig. 12-7. The low-temperature heating of the transfer substrate 64 and the display substrate 71 by the heating platform can promote the atomic diffusion of the bonding interface, and improve the bonding efficiency and quality. And the first high-frequency mechanical vibration Z (which may be but is not limited to vibration generated by ultrasonic waves) may also break the oxide layer film on the surface of the second bonding pad on the display substrate, so that the bonding success rate is higher.
S1309: the lifting of the transfer head is controlled by the Z-axis moving platform.
Since the Micro LED chip is already bonded on the display substrate, the suction force of the transfer head for picking up the Micro LED chip is not enough to take away the bonded Micro LED chip, so that the suction force generated when picking up the chip can be maintained when controlling the transfer head to ascend in the present example; therefore, the Micro LED chips with bonding problems can be picked up by the transfer head to leave the display substrate, so that the chip bonding area with chip transfer failure can be found conveniently, and the subsequent repairing process is facilitated. For example, as shown in fig. 12 to 8, it is assumed that, in the current chip transfer process, there is a residual Micro LED chip C with a problem in bonding when the transfer head 2 is raised, and a target bonding area of the residual Micro LED chip C on the display substrate is obtained. So as to re-transfer the Micro LED chip to the target bonding area in the subsequent repairing process. The transition may be performed by, but not limited to, steps S1305 to S1309. Chip transfer can also be performed by adopting other chip transfer modes, which are not described herein again.
In some application scenes, the same COW can only generate Micro LED chips with a single light-emitting color in the production process, when three kinds of Micro LED chips of red, green and blue need to be transferred to a display substrate in batches in the production process, when the chip transfer device provided by the invention is used for chip transfer, required three kinds of Micro LED chip spacing arrangement of red, green and blue can be set in the production process of the COW, the chips are transferred to the display substrate in batches, and because the heating temperature of a bearing table is not high enough to melt the Micro LED chips which are bonded (wherein the melting point of gold is 1064.18 ℃, and the melting point of aluminum is 660.4 ℃), the Micro LED chips which are previously bonded in a transfer way cannot be influenced in the process of chip transfer of subsequent batches; and because the chip transfer device has the advantages, the chip transfer device is also particularly suitable for the repairing process of the Micro LED chip.
S1310: and controlling the heating platform to heat the display substrate on the bearing table to a third temperature range (for example, more than 660.4 ℃) and then stopping working, so that the bonded second bonding pad is melted.
Through the step, after the second bonding pad is changed from a high-temperature melting state to a low-temperature curing state, the bonding quality between the bonded first bonding pad and the bonded second bonding pad can be further improved. And because only once integral high-temperature heating is needed to be carried out on the display substrate, the influence on the high-temperature heating of the display substrate can be reduced to the minimum.
Another alternative embodiment:
the embodiment provides a display back plate, which comprises a display substrate, wherein a plurality of chip bonding areas are arranged on the display substrate, the display back plate further comprises micro LED chips arranged in the chip bonding areas, and at least one micro LED chip is transferred to the chip bonding areas by adopting the chip transfer method shown in the embodiment.
The embodiment also provides a display, which comprises a frame and the display back plate as shown above; the display back plate is fixed on the frame. The display can be various electronic devices which make display by using the display back plate as shown above, and examples of the electronic devices can include, but are not limited to, various intelligent mobile terminals, vehicle-mounted terminals, PCs, displays, electronic billboards and the like.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims (11)

1. A chip transfer apparatus, comprising:
the circuit board comprises a bearing table, a first bonding pad and a second bonding pad, wherein the bearing table is configured to bear a circuit board, a chip bonding area is arranged on the circuit board, the second bonding pad corresponding to the first bonding pad on the chip is arranged in the chip bonding area, and when the circuit board is borne on the bearing table, the second bonding pad is far away from one surface of the bearing table, which is in contact with the circuit board;
a transfer head configured to pick up a chip from a transfer substrate, a first pad of the chip picked up by the transfer head, a side away from the chip in contact with the transfer head;
the motion control platform is configured to drive the transfer head and/or the bearing table to move so as to butt a first bonding pad of a chip picked up by the transfer head with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and generate relative pressure between the butted first bonding pad and the second bonding pad;
a vibration control platform configured to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the chip picked by the transfer head and/or the circuit substrate carried by the bearing platform, so that the first bonding pad and the second bonding pad which are butted are bonded under the high-frequency mechanical vibration and the pressure.
2. The chip transfer apparatus according to claim 1, wherein the vibration control stage includes at least one of a first vibration generating component and a second vibration generating component;
the first vibration generating component comprises a first electric signal generator, a first transducer and a first amplitude transformer, wherein the first amplitude transformer is positioned between the first transducer and the transfer head, and the first transducer is configured to convert a first high-frequency electric signal output by the first electric signal generator into first high-frequency mechanical vibration and transmit the first high-frequency mechanical vibration to a chip picked up by the transfer head through the first amplitude transformer;
the second vibration generating component comprises a second electric signal generator, a second transducer and a second amplitude transformer, wherein the second amplitude transformer is positioned between the second transducer and the bearing platform, and the second transducer is configured to convert a second high-frequency electric signal output by the second electric signal generator into second high-frequency mechanical vibration and transmit the second high-frequency mechanical vibration to the circuit substrate on the bearing platform through the second amplitude transformer.
3. The chip transfer apparatus according to claim 2, wherein when the vibration control stage includes a first vibration generating part and a second vibration generating part, at least one of a phase and a frequency of the first high-frequency electric signal and the second high-frequency electric signal is different.
4. The chip transfer device according to any one of claims 1 to 3, further comprising a heating stage configured to heat the circuit substrate on the carrier table to a first temperature range, a maximum temperature value in the first temperature range being less than a first temperature threshold value at which the first bonding pad melts and less than a second temperature threshold value at which the second bonding pad melts.
5. The chip transfer device according to claim 4, wherein the carrier stage is further configured to carry the transfer substrate, and the heating platform is further configured to heat the transfer substrate on the carrier stage to a second temperature range, wherein a maximum temperature value in the second temperature range is smaller than the first temperature critical value and the second temperature critical value.
6. The chip transfer apparatus according to claim 4, wherein the heating platform is further configured to heat the circuit substrate on the carrier table to a third temperature range after the second bonding pad in each chip bonding region of the circuit substrate is bonded to the first bonding pad of the corresponding chip, and a minimum temperature value in the third temperature range is greater than or equal to the first temperature critical value and/or the second temperature critical value.
7. A method of chip transfer, comprising:
disposing a circuit substrate on a stage of the chip transfer apparatus according to any one of claims 1 to 6;
picking up a chip from a transfer substrate by the transfer head;
controlling the transfer head and/or the bearing table to move so as to enable a first bonding pad of a chip picked up by the transfer head to be butted with a second bonding pad in the corresponding chip bonding area on the circuit substrate, and enabling relative pressure to be generated between the butted first bonding pad and the butted second bonding pad;
and controlling the vibration control platform to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the chip picked by the transfer head and/or the circuit substrate borne by the bearing table, so that the first bonding pad and the second bonding pad which are butted are bonded under the high-frequency mechanical vibration and the pressure.
8. The chip transfer method according to claim 7, further comprising, before the butted first and second pads complete bonding under the high frequency mechanical vibration and the pressure:
and controlling a heating platform of the chip transfer device to heat the circuit substrate on the bearing table to a first temperature range, wherein the maximum temperature value in the first temperature range is smaller than a first temperature critical value for melting the first bonding pad and is smaller than a second temperature critical value for melting the second bonding pad.
9. The chip transfer method according to claim 8, further comprising, before picking up a chip from a transfer substrate by the transfer head:
arranging the transfer substrate on the bearing table;
controlling a heating platform of the chip transfer device to heat the transfer substrate on the bearing table to a second temperature range; the maximum temperature value in the second temperature range is smaller than a first temperature critical value for melting the first bonding pad and smaller than a second temperature critical value for melting the second bonding pad.
10. The chip transfer method according to claim 8, wherein the controlling the vibration control platform to generate high-frequency mechanical vibration so that the first and second pads that are butted are bonded under the high-frequency mechanical vibration and the pressure, further comprises:
controlling the transfer head to be away from the circuit substrate in a state of maintaining an adsorption force generated when the chip is picked up;
when the transfer head adsorbs a residual chip, removing the residual chip and obtaining a target chip bonding area corresponding to the residual chip on the circuit substrate;
picking up a chip of the same type as the residual chip from a transfer substrate as a supplementary chip by the transfer head;
controlling the transfer head and/or the bearing table to move so as to butt a first bonding pad of a supplementary chip picked up by the transfer head with a second bonding pad in the target chip bonding area on the circuit substrate, and generating relative pressure between the butted first bonding pad and the butted second bonding pad;
and controlling the vibration control platform to generate high-frequency mechanical vibration, wherein the high-frequency mechanical vibration acts on the supplementary chip and/or the circuit substrate, so that the first bonding pad and the second bonding pad which are butted are bonded under the high-frequency mechanical vibration and the pressure.
11. A display backplane comprising a display substrate provided with a plurality of chip bonding regions, and micro LED chips provided within the plurality of chip bonding regions, the micro LED chips being transferred to the chip bonding regions by the chip transfer method according to any one of claims 7 to 10.
CN202110444465.6A 2021-04-23 2021-04-23 Chip transfer method and device and display backboard Pending CN115241355A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110444465.6A CN115241355A (en) 2021-04-23 2021-04-23 Chip transfer method and device and display backboard

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110444465.6A CN115241355A (en) 2021-04-23 2021-04-23 Chip transfer method and device and display backboard

Publications (1)

Publication Number Publication Date
CN115241355A true CN115241355A (en) 2022-10-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110444465.6A Pending CN115241355A (en) 2021-04-23 2021-04-23 Chip transfer method and device and display backboard

Country Status (1)

Country Link
CN (1) CN115241355A (en)

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