CN115483337A - LED repairing method, display screen and electronic equipment - Google Patents

LED repairing method, display screen and electronic equipment Download PDF

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Publication number
CN115483337A
CN115483337A CN202110604539.8A CN202110604539A CN115483337A CN 115483337 A CN115483337 A CN 115483337A CN 202110604539 A CN202110604539 A CN 202110604539A CN 115483337 A CN115483337 A CN 115483337A
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China
Prior art keywords
led chip
repairing
repaired
bonding layer
repair
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李强
蔡明达
萧俊龙
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 CN202110604539.8A priority Critical patent/CN115483337A/en
Publication of CN115483337A publication Critical patent/CN115483337A/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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • 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
    • 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
    • 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)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Theoretical Computer Science (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

The invention relates to an LED repairing method, a display screen and electronic equipment, wherein a repairing bonding layer is additionally arranged on a repairing bonding area, so that the sum of the thickness of the repairing bonding layer and the height of a repaired LED chip is greater than the height of a qualified reserved LED chip, when a transfer head applies pressure to the repaired LED chip, the transfer head cannot contact the qualified reserved LED chip on a driving backboard, and the pressure can be effectively applied to the repaired LED chip, so that the reliability of bonding between the repaired LED chip and the driving backboard can be improved, the condition that the qualified reserved LED chip is damaged in the LED repairing process can be avoided, and the quality of the display screen is improved. Moreover, due to the existence of the bonding layer for repairing, the repairing process is realized without depending on melting of the initial bonding layer, the high temperature required by melting of the bonding materials is avoided, the qualified reserved LED chip and the repaired LED chip on the driving backboard are protected, and the quality of the display screen is enhanced.

Description

LED repairing method, display screen and electronic equipment
Technical Field
The invention relates to the technical field of LEDs, in particular to an LED repairing method, a display screen and electronic equipment.
Background
In the manufacturing process of the display screen, a Bonding material is usually disposed in an area to be disposed with the LED chip on the driving backplane, and then a large amount of LED chips transferred from the driving backplane are bonded to the driving backplane by using a hot pressing method. And after the LED chips are transferred and bonded to the driving backboard, the LED chips with the dead points on the driving backboard are detected by utilizing a lighting test, and the LED chips with the dead points are replaced and repaired by repairing the LED chips.
Under the condition, when the LED chip is bonded to the driving backboard, the transfer head is blocked by the qualified reserved LED chip, so that the transfer head cannot apply pressure to the repaired LED chip, the repaired LED chip cannot be reliably bonded to the driving backboard, and the reliability of the display screen is influenced; furthermore, the acceptable remaining LED chip is short-circuited by being subjected to pressure applied by the transfer head, or is firmly bonded to the transfer head by the pressure and is thus stuck by the transfer head.
Therefore, how to improve the bonding reliability between the repaired LED chip and the driving backplane without damaging the qualified reserved LED chip is an urgent problem to be solved.
Disclosure of Invention
In view of the above deficiencies of the related art, the present application aims to provide an LED repairing method, a display screen, and an electronic device, and aims to solve the problems that in an LED repairing process, a repaired LED chip cannot be reliably bonded with a driving backplane, and the LED chip is qualified and remains and is easily damaged.
The application also provides an LED repairing method, which comprises the following steps:
after the bad point LED chip on the driving backboard is removed, a bonding layer for repairing is additionally arranged on a repairing bonding area, the repairing bonding area is an area where the repairing LED chip is bonded with the driving backboard, and the sum of the thickness of the bonding layer for repairing and the height of the repairing LED chip is larger than the height of the qualified reserved LED chip on the driving backboard;
the transfer head is controlled to pick up the repaired LED chip, the repaired LED chip is aligned with a region to be repaired on the driving backboard, and the region to be repaired is a region for deploying the repaired LED chip on the driving backboard;
applying pressure towards the driving backboard to the repair LED chip through the transfer head so as to bond the repair LED chip to the driving backboard by using the bonding layer for repairing.
According to the LED repairing method, after the defective LED chip is removed, the bonding layer for repairing is additionally arranged on the repairing bonding area for bonding and repairing the LED chip, so that the effect that the sum of the thickness of the bonding layer for repairing and the height of the repaired LED chip is larger than the height of the qualified reserved LED chip is achieved, when the transfer head applies pressure to the repaired LED chip, the qualified reserved LED chip on the driving backboard is not contacted, the pressure can be effectively applied to the repaired LED chip, the reliability of bonding between the repaired LED chip and the driving backboard can be improved, the condition that the qualified reserved LED chip is damaged in the LED repairing process can be avoided, and the quality of the display screen is improved. Moreover, because the bonding layer for repairing is additionally arranged in the process of repairing the LED, the LED chip does not need to be bonded and repaired by melting the bonding material corresponding to the dead LED chip in the process of repairing the LED, so that the high temperature required by melting the bonding material is avoided, the qualified reserved LED chip and the repaired LED chip on the driving backboard are protected, and the quality of the display screen is enhanced.
Optionally, the repairing bonding region is located on an electrode of the repairing LED chip, and adding a bonding layer for repairing on the repairing bonding region includes: and arranging a bonding layer for repairing on the electrode of the LED chip.
Optionally, the step of providing a bonding layer for repairing on the electrode of the repaired LED chip comprises:
and evaporating a metal layer with the melting point lower than 200 ℃ on the electrode of the repaired LED chip to form a bonding layer for repairing.
According to the LED repairing method, the bonding layer for repairing is arranged on the electrode for repairing the LED chip, and the bonding layer for repairing is made of the metal material with the melting point lower than 200 ℃, so that the bonding between the LED chip for repairing and the driving backboard can be avoided by adopting an over-high temperature in the LED repairing process, the LED chip on the driving backboard is protected, the repairing effect is enhanced, and the quality of the display screen is improved.
Optionally, the repairing bonding region is located on the driving backplane, and adding a bonding layer for repairing on the repairing bonding region includes: and additionally arranging a bonding layer for repairing in the region to be repaired of the driving backboard.
Optionally, adding a bonding layer for repairing in a region to be repaired of the driving backplane includes:
paving an ACF (Anisotropic Conductive Film) as a bonding layer for repairing on one side of the driving backboard, which is provided with the qualified reserved LED chip, wherein the ACF covers the area to be repaired, and the area of the ACF is larger than that of the area to be repaired;
applying pressure towards the driving backplane to the repair LED chip by the transfer head to bond the repair LED chip to the driving backplane with the bonding layer for repair comprises:
the transfer head applies pressure towards the driving backboard to the repaired LED chip, so that the repaired LED chip drives the ACF to move towards the area to be repaired until the repaired LED chip and the area to be repaired are bonded together through the ACF, and the insulating film covering the conductive particles in the ACF is broken.
In the LED repairing method, the ACF is arranged on the driving backboard to serve as the bonding layer for repairing, so that the bonding material is not required to be melted by high temperature in the LED repairing process, and the LED chip is protected from being repaired and the qualified reserved LED chip is protected.
Optionally, after the repairing LED chip is bonded to the driving backplane by using the bonding layer for repairing, the method further includes:
placing the driving backboard in an NMP (N-methylpyrrolidone) solution, and removing redundant ACF by using the NMP solution;
and cleaning and drying the driving back plate.
Based on the same inventive concept, the present application further provides a display screen, which is characterized by comprising:
driving the back plate; and
the LED chips are arranged on the driving back plate and are electrically connected with the driving circuit in the driving back plate;
the LED chips comprise repaired LED chips and qualified reserved LED chips which are not repaired; a bonding layer for repairing is arranged between the repairing LED chip and the driving backboard and used for bonding the repairing LED chip and the driving backboard; the sum of the thickness of the bonding layer for repairing and the height of the repaired LED chip is larger than the height of the qualified reserved LED chip.
The LED chip in the display screen comprises a repaired LED chip and an unrepaired qualified reserved LED chip, a bonding layer for repairing is arranged between the repaired LED chip and the driving backboard, the sum of the thickness of the bonding layer for repairing and the height of the repaired LED chip is greater than the height of the qualified reserved LED chip, therefore, in the repairing process of the LED, when the transfer head applies pressure to the repaired LED chip, the qualified reserved LED chip on the driving backboard can not be contacted, the pressure can be effectively applied to the repaired LED chip, the reliability of bonding between the repaired LED chip and the driving backboard can be improved, the damaged condition of the qualified reserved LED chip in the repairing process of the LED can also be avoided, and the quality of the display screen is improved. Moreover, because the bonding layer for repairing is additionally arranged in the process of repairing the LED, the LED chip is not required to be bonded and repaired by melting the bonding material corresponding to the defective LED chip in the process of repairing the LED, so that the high temperature required by melting the bonding material is avoided, the qualified reserved LED chip and the repaired LED chip on the driving backboard are protected, and the quality of the display screen is enhanced.
Optionally, the specification of the repaired LED chip is consistent with the specification of the qualified reserved LED chip.
Optionally, the bonding layer for repairing includes at least one of a metal layer and an ACF, and the metal layer is made of a metal having a melting point lower than 200 ℃.
In the LED repairing method, the bonding layer for repairing comprises at least one of a metal layer and ACF, and the metal layer is made of metal with the melting point lower than 200 ℃. Therefore, the bonding of the LED chip and the driving backboard can be prevented from being repaired by adopting overhigh temperature in the LED repairing process, the LED chip on the driving backboard is protected, the repairing effect is enhanced, and the quality of the display screen is improved.
Based on the same inventive concept, the application further provides electronic equipment which comprises a processor and the display screen in any one of the preceding claims, wherein the display screen is in communication connection with the processor.
The LED chip in the display screen of the electronic equipment comprises a repaired LED chip and an unrepaired qualified reserved LED chip, a bonding layer for repairing is arranged between the repaired LED chip and the driving backboard, the sum of the thickness of the bonding layer for repairing and the height of the repaired LED chip is greater than the height of the qualified reserved LED chip, therefore, in the repairing process of the LED, when the transfer head applies pressure to the repaired LED chip, the qualified reserved LED chip on the driving backboard can not be contacted, the pressure can be effectively applied to the repaired LED chip, the reliability of bonding between the repaired LED chip and the driving backboard can be improved, the condition that the LED chip is damaged in the LED repairing process can be avoided, and the quality of the display screen is improved. Moreover, because the bonding layer for repairing is additionally arranged in the process of repairing the LED, the bonding material corresponding to the LED chip with the defective point is not required to be melted to bond and repair the LED chip in the process of repairing the LED, so that the high temperature required by melting the bonding material is avoided, the qualified reserved LED chip and the repaired LED chip on the driving backboard are protected, and the quality of the electronic equipment is enhanced.
Drawings
FIG. 1 is a schematic diagram illustrating a state of the art LED repair scheme according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for repairing an LED according to an alternative embodiment of the present invention;
FIG. 3 is a schematic diagram of an ACF disposed on a driving backplane as a bonding layer for repairing according to an alternative embodiment of the present invention;
FIG. 4 is a schematic diagram of an LED repair scheme shown in an alternative embodiment of the present invention;
FIG. 5 is a schematic diagram of an alternative embodiment of a display screen;
FIG. 6 is a flow chart of a method for repairing an LED provided in an alternative embodiment of the present invention;
FIG. 7 is a schematic view of a process state of the LED repairing method of FIG. 6;
FIG. 8 is a flow chart of a method of repairing an LED provided in an alternative embodiment of the present invention;
fig. 9 is a schematic diagram illustrating a process status of the LED repairing method in fig. 8.
Description of reference numerals:
100-driving a back plate; 101-an initial bonding layer; 102-an LED chip; 102 a-qualified reserved LED chip 102a;102 b-dead LED chips; 102 c-repairing the LED chip; 300-driving the back plate; 301-a region to be repaired; 302-ACF; 303-initial bonding layer; 400-driving the back plate; 401 — a bonding layer for repair; 402-repairing the LED chip; 404-a transfer head; 50-a display screen; 51-a drive backplane; 52-LED chip; 52 a-qualified retained LED chips; 52 b-repair of LED chips; 53-bonding layer for repair; 700 a-a growth substrate; 700 b-transient substrate; 700 c-a drive backplane; 71-repairing the LED chip; 72-a bonding layer for repairing; 73-qualified retention of the LED chip; 900 a-a drive backplane; 900 b-transient substrate; 91-repairing the LED chip; 92-ACF; 93-qualified to retain the LED chip.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application 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 application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
In recent years, micro-LEDs (Micro light emitting diodes) have been attracting attention due to their excellent display effects, but there are not few technical difficulties in the field of Micro-LED manufacturing, such as mass transfer, mass detection, and mass repair. For example, in a currently common manufacturing process, a thermal pressing method is mostly adopted to bond the LED chip to the driving backplane during mass transfer, and after the mass transfer, mass detection is performed on the LED chip on the driving backplane to detect a defective LED chip on the driving backplane, so that the defective LED chip can be repaired by using a repairing LED chip after the defective LED chip is removed by using a removing device. However, the thermal pressing process at the bulk transfer stage may cause the bonding material on the driving backplane to become low, the process of removing the defective LED chip may also cause the bonding material to become thin, and the bonding material to be oxidized and doped with impurities, thereby causing the melting point of the bonding material to become high, a higher temperature is required when the LED chip is repaired by thermal pressing, and the high temperature is likely to damage the repaired LED chip and the qualified remaining LED chip after the initial bulk transfer.
For example, referring to fig. 1 (a), an initial bonding layer 101 formed by a bonding material is disposed on the driving backplane 100, and a height of the initial bonding layer 101 is denoted as h1. In fig. 1 (b), the transfer head picks up the LED chip 102 and aligns with the initial bonding layer 101 on the driving backplane 100. After thermocompression, the height of the initial bonding layer 101 under the LED chip 102 becomes low, where the height of the initial bonding layer 101 is denoted as h2, and h2 is smaller than h1 in fig. 1 (c). In fig. 1 (d), a lighting test is performed on the LED chips on the driving back plate 100, and the qualified reserved LED chips 102a and the defective LED chips 102b in the LED chips 102 are tested. In fig. 1 (e), the dead LED chip 102b on the driving back plate 100 is removed with a removing device; in fig. 1 (f), the transfer head is used to pick up the repair LED chip 102c according to the arrangement of the defective LED chip 102b on the driving backplane 100, and align the repair LED chip 102c with the exposed region to be repaired on the driving backplane 100 after the defective LED chip 102b is removed. Subsequently, in (g) of fig. 1, the transfer head applies a pressure to the repair LED chip 102c toward the driving back plate 100, so that the repair LED chip 102c is bonded with the melted initial bonding layer in the region to be repaired.
In general, the specification of the repair LED chip 102c is consistent with the specification of the qualified and reserved LED chip 102a, which results in that the pressure applied by the transfer head to the repair LED chip 102c is more borne by the qualified and reserved LED chip 102a, and the repair LED chip 102c cannot be reliably bonded with the initial bonding layer thereunder; but the qualified LED chip 102a is left without short circuit due to the pressure of the transfer head. Moreover, since LLO (Laser Lift-Off) is used when the defective LED chip 102b is removed, the bonding material in the initial bonding layer 101 is oxidized, which results in high melting point, which results in higher hot pressing temperature when bonding and repairing the LED chip 102c, and the high temperature further damages the LED chip 102a and the repaired LED chip 102c.
Based on this, the present application intends to provide a solution to the above technical problem, the details of which will be set forth in the following embodiments.
An alternative embodiment:
first, the present embodiment provides an LED repairing method, please refer to the flowchart of the LED repairing method shown in fig. 2:
s202: and after the bad point LED chip on the driving backboard is removed, a bonding layer for repairing is additionally arranged on the repairing bonding area.
In this embodiment, after removing the defective LED chip on the driving backplane, a bonding layer for repairing may be added on the repairing bonding region, where the repairing bonding region is a region where the repairing LED chip is bonded with the driving backplane, and therefore, the repairing bonding region may be located on the repairing LED chip, or on the driving backplane, or on both the driving backplane and the repairing LED chip. For example, in some examples of the present embodiment, the repair bonding region is located on the repair LED chip, because the portion contacting and combining with the driving backplane is an electrode of the repair LED chip when the repair LED chip is bonded with the driving backplane, the repair bonding region may be located on the electrode of the repair LED chip; in other examples, the repair bonding region is located on the driving backplane, and the portion of the driving backplane, which is in contact bonding with the repair LED chip, is a region to be repaired in the driving backplane, so in one example, a bonding layer for repair may be added on the primary bonding layer in the region to be repaired. In some examples, a repairing bonding layer may be added on the initial bonding layer in the repairing region and the electrode of the LED chip.
The bonding layer for repairing is used for fixing the repaired LED chip and the driving backboard and electrically connecting the repaired LED chip and the driving backboard in the process of bonding the repaired LED chip to the driving backboard, so the bonding layer for repairing should have the capability of combining the driving backboard and the repaired LED chip and should also have conductivity.
In some examples of this embodiment, the repair bonding layer may be a metal layer. For example, in some examples of the present embodiment, the bonding layer for repairing may be a copper layer, a silver layer, or a gold layer, and in some examples of the present embodiment, in order to reduce the temperature required for bonding and repairing the LED chip, it may be considered that some metal material with a relatively low melting point is used to form the bonding layer for repairing, for example, the bonding layer for repairing may be a metal layer with a melting point lower than 200 ℃. For example, in some examples, the material of the repair bonding layer includes at least one of indium (melting point 158 ℃), bismuth (melting point 98 ℃).
In some examples of the embodiment, the bonding layer for repairing is a metal layer evaporated on the electrode of the repairing LED chip, for example, in one example of the embodiment, indium metal may be evaporated on the electrode of the repairing LED chip, so as to form the bonding layer for repairing. Of course, those skilled in the art will understand that, in other examples, the repairing bonding layer may also be evaporated in the region to be repaired of the driving backplane, for example, the repairing bonding layer may be further evaporated on the initial bonding layer.
In other examples of this embodiment, the repairing bonding layer may also have conductivity in some states and a film layer that does not have conductivity in other states, for example, in some examples, the repairing bonding layer may be an ACF, which is characterized by a significant difference between the Z-axis electrical conduction direction and the resistance characteristics of the XY insulation plane. The ACF may have conductivity in the Z-axis direction due to a rupture of an insulating film (e.g., a resin film) including conductive particles therein under pressure. In some examples, after the ACF is segmented into a size adaptive to the area of the region to be repaired on the driving backplane, the segmented ACF may be placed in the region to be repaired of the driving backplane; in still other examples, the segmented ACF may be attached to the electrodes of the repair LED chip.
In some examples of the embodiment, without dividing the ACF, after the LED chip with the defective pixel is removed, an ACF may be directly disposed on a side of the driving backplane where the LED chip is disposed, the ACF covers the region to be repaired, and an area of the ACF is larger than an area of the region to be repaired, and in general, an ACF may cover a plurality of regions to be repaired, and even in an example, an ACF302 may cover all the regions 301 to be repaired on the driving backplane 300, as shown in fig. 3. Although the ACF302 in fig. 3 is temporarily not in direct contact with the initial bonding layer 303 in the area to be repaired, as the transfer head applies pressure to the repaired LED chip, the repaired LED chip will move the ACF302 toward the driving backplane 300 until the ACF302 is bonded with the initial bonding layer 303 in the area to be repaired 301.
S204: and controlling the transfer head to pick up the repaired LED chip and aligning the repaired LED chip with the region to be repaired on the driving backboard.
In this embodiment, after the bonding layer for repairing is added, the transfer head can pick up and repair the LED chip. The transfer head may pick up the repaired LED chip from the temporary substrate using magnetic force, van der waals force, or the like. Optionally, the transfer head may obtain the repaired LED chips from the transient substrate according to the arrangement of the regions to be repaired on the driving backplane, and thus, the positions and distances between the repaired LED chips on the transfer head are the same as the positions and distances of the regions to be repaired on the driving backplane.
After picking up the repaired LED chip, the transfer head can carry the repaired LED chip to move above the driving backboard, and align the repaired LED chip with the region to be repaired on the driving backboard.
S206: applying pressure towards the driving backboard to the repair LED chip through the transfer head so as to bond the repair LED chip to the driving backboard by using the bonding layer for repairing.
After the repaired LED chip is aligned with the area to be repaired, the pressure towards the driving backboard from the repaired LED chip support can be applied through the transfer head, the transfer head can carry the repaired LED chip to move towards the driving backboard, and as the bonding layer for repairing is arranged in the repairing bonding area as shown in fig. 4, and the sum of the thickness of the bonding layer 401 for repairing and the height of the repaired LED chip 402 is larger than the height of the qualified reserved LED chip 403, the transfer head 404 can not touch the qualified reserved LED chip 403 when the repaired LED chip 402 is in contact with the driving backboard 400, so that the pressure applied to the repaired LED chip 402 by the transfer head 404 can not be borne by the qualified reserved LED chip 403, and the qualified reserved LED chip 403 can not be damaged and shorted due to the pressure naturally; the repaired LED chip 402 can be tightly bonded to the driving backplane 400 under pressure to achieve bonding.
It can be understood that, if the repairing bonding layer disposed in the repairing bonding region is a metal layer, when bonding the repairing LED chip, the repairing bonding layer needs to be melted to make the metal layer in a molten state, so that the electrode of the repairing LED chip can be connected to the initial bonding layer in the region to be repaired. For example, in some examples of the present embodiment, the bonding repair LED chip still employs a thermocompression process. If the bonding layer for repairing arranged in the repairing bonding area is the ACF, one surface of the ACF can be directly bonded on the initial bonding layer in the area to be repaired by pressure, and the other surface of the ACF is bonded on the electrode of the LED chip to be repaired. Meanwhile, the pressure applied by the transfer head should be sufficient to break the insulating film covering the conductive particles in the ACF, so that the ACF has conductivity.
If the added bonding layer for repairing is a large-area ACF corresponding to at least two areas to be repaired, which is arranged on the driving backboard, after the LED chip to be repaired is bonded to the corresponding area to be repaired by using the ACF, the actually useful area of the ACF is the area between the driving backboard and the LED chip to be repaired, and other areas are redundant areas, so that the redundant ACF also needs to be removed after the bonding of the LED chip to be repaired is completed. In some examples of the embodiment, the driving backplane may be placed in an ACF removal solution, and the ACFs may chemically react with the ACF removal solution to remove excess ACFs, and the useful ACFs placed in the driving backplane after bonding the repair LED chip may not be removed by the ACF removal solution due to the shielding of the repair LED chip. In some examples of this embodiment, the ACF removal solution may be an NMP (N-methylpyrrolidone) solution. The driving back plate is placed in NMP solution, and after redundant ACF is removed by the NMP solution, the driving back plate can be cleaned and dried.
As shown in fig. 5, the display screen 50 includes a driving back plate 51 and a plurality of LED chips 52, wherein the plurality of LED chips 52 include an LED chip 52a that is qualified after the first transfer, and a repaired LED chip 52b that is set in a subsequent repairing process. In the display screen 50, the repairing bonding layer 53 is arranged between the repairing LED chip 52b and the driving backboard 51, but the repairing bonding layer 53 is not arranged between the qualified reserved LED chip 52a and the driving backboard 51, and the sum of the thickness of the repairing bonding layer 53 and the height of the repairing LED chip 52b is greater than the height of the qualified reserved LED chip 52a, so that when the repairing LED chip 52b contacts the driving backboard 51, the transfer head does not touch the qualified reserved LED chip 52a, the pressure applied to the repairing LED chip 52b by the transfer head is naturally not born by the qualified reserved LED chip 52a, and the qualified reserved LED chip 52a is not damaged and short-circuited by the pressure; the repaired LED chip 52b can be tightly combined with the driving back plate 51 under the action of pressure, so as to improve the quality of the display screen 50.
Moreover, when the repaired LED chip 52b is bonded, the bonding material for bonding the repaired LED chip 52b and the driving back plate 51 is the bonding material in the bonding layer 53 for repairing, so that when the repaired LED chip 52b is bonded, the initial bonding layer does not need to be melted again, and the damage to the repaired LED chip 52b or the qualified reserved LED chip 52a caused by the high temperature required for melting the oxidized initial bonding layer is avoided.
In some examples of the embodiment, the repairing bonding layer 53 may include at least one of a metal layer and an ACF, and in some examples, the repairing bonding layer 53 may include both the metal layer and the ACF, for example, the metal layer may be disposed near an electrode of the repairing LED chip 52b, and the ACF is closer to the driving back plate 51. Alternatively, when the bonding layer 53 for repairing includes a metal layer, the metal layer may be composed of a metal having a melting point lower than 200 ℃, for example, the metal layer includes, but is not limited to, at least one of indium and bismuth.
In some examples of the present embodiment, the specifications of the repair LED chip 52b and the qualified reserved LED chip 52a may be different, but in other examples, the specifications of the repair LED chip 52b and the qualified reserved LED chip 52a are the same, and in these cases, as long as the repair bonding layer is provided in the repair bonding region, the sum of the thickness of the repair bonding layer 53 and the height of the repair LED chip 52b can be ensured to be greater than the height of the qualified reserved LED chip 52 a.
The LED chip on the driving back plate 51 may be an LED chip with a flip structure, or an LED chip with a forward mounting structure; meanwhile, the LED chips may be Micro-LEDs, or may be other types of LED chips, for example, but not limited to, mini-LEDs (mini-LEDs) or OLEDs (Organic Light-Emitting diodes).
The display screen 50 can be applied to various electronic devices, such as a mobile phone, a tablet computer, a wearable device, a desktop computer, etc., so the embodiment further provides an electronic device, which includes the display screen 50, it can be understood that, in the electronic device, besides the display screen 50, other devices, such as a processor, can be included, and the display screen 50 can be in communication connection with the processor and displays under the control of the processor. Besides, the electronic device may further include one or more of an RF (Radio Frequency) unit, a WiFi module, an audio output unit, an a/V (audio/video) input unit, a sensor, a user input unit, an interface unit, a memory, and the like. It is understood that the display screen may also be an LED screen applied outdoors.
The LED repairing method provided by the embodiment has the advantages that the bonding layer for repairing is additionally arranged in the repairing bonding area, the height of the LED chip for repairing is increased by the aid of the bonding layer for repairing, in the LED repairing process, when the transfer head applies pressure to the LED chip for repairing, the LED chip can not be remained in a qualified mode on the driving backboard, pressure can be effectively exerted on the LED chip for repairing, the reliability of bonding between the LED chip for repairing and the driving backboard can be improved, the condition that the LED chip is remained in a qualified mode in the LED repairing process can also be avoided, and the quality of a display screen is improved. Moreover, due to the existence of the bonding layer for repairing, the bonding material corresponding to the LED chip with the defective point does not need to be melted to bond and repair the LED chip in the LED repairing process, so that the high temperature required by melting the bonding material is avoided, the qualified reserved LED chip and the repaired LED chip on the driving backboard are protected, and the quality of the electronic equipment is enhanced.
Another alternative embodiment:
in this embodiment, an LED repairing method is provided, please refer to a flowchart of the LED repairing method shown in fig. 6 and a schematic diagram of a repairing process state shown in fig. 7:
s602: and after the defective LED chip on the driving backboard is removed, a bonding layer for repairing is arranged on the electrode for repairing the LED chip.
The specific process for removing the defective LED chip and the process before removing the defective LED chip have been described in detail above, and are not described herein again.
In this embodiment, when the defective LED chip on the driving backplane is removed, the initial bonding layer between the defective LED chip and the driving backplane is not removed.
In this embodiment, since the repair bonding region is located on the electrode of the repair LED chip, after the defective LED chip is removed, the repair bonding layer 72 needs to be added on the electrode of the repair LED chip 71, as shown in (a) and (b) of fig. 7, the repair LED chip 71 is located on the growth substrate 700a, and in this example, a metal layer may be disposed on the electrode of the repair LED chip 71 by using vapor deposition as the repair bonding layer 72. For example, the repair bonding layer 72 may be a metal layer containing indium or a metal layer containing bismuth. It can be understood that, since the bonding layer 72 for repairing is only required to be disposed on the electrode of the repaired LED chip 71, in order to prevent the metal layer from being formed on the epitaxial layer of the repaired LED chip during the evaporation process or on the growth substrate 700a, before the bonding layer 72 for repairing is formed by evaporation, a mask made of a photoresist material may be formed by coating the photoresist on the side of the growth substrate 700a where the repaired LED chip 71 is disposed, performing exposure, development, and the like, and the mask may shield the region where the metal layer is not required to be covered, and only expose the electrode of the repaired LED chip 71. In this case, the deposition is performed to ensure that the metal layer is formed only on the electrode. After the formation of the metal layer for the repair bonding layer 72 is completed, the photoresist is also removed.
It should be understood that, in some other examples, the process of providing the metal layer on the electrode of the repair LED chip 71 may be any one of other processes, such as sputtering, PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition), ALD (atomic layer Deposition), and PECVFD (plasma enhanced Chemical Vapor Deposition).
In the present embodiment, the repaired LED chip 71 and the qualified reserved LED chip transferred to the driving back plate may have the same specification, or even both of them may be LED chips grown in the same batch, so that the repaired LED chip 71 and the qualified reserved LED chip have the same height.
S604: and transferring the repaired LED chip to a temporary storage substrate.
In some examples, one side of the temporary storage substrate 700b is provided with a photoresist layer, and the side of the temporary storage substrate 700b provided with the photoresist layer is close to the repair LED chip 71 on the growth substrate 700a, as shown in fig. 7 (c), until the repair LED chip 71 is adhered to the photoresist layer, and then the repair LED chip 71 and the growth substrate 700a are peeled off by laser peeling, so that the repair LED chip 71 is transferred to the temporary storage substrate 700b, as shown in fig. 7 (d).
S606: and controlling the transfer head to selectively pick up and repair the LED chips from the temporary storage substrate according to the arrangement of the areas to be repaired on the driving back plate.
On one hand, the transfer head is used to adsorb the repair LED chips 71 to be picked up by magnetic force or van der waals force, and on the other hand, the laser is used to peel the repair LED chips 71 selected by the transfer head from the temporary storage substrate 700b, so that the transfer head picks up the repair LED chips 71, as shown in fig. 7 (e) and 7 (f).
S608: and controlling the transfer head to carry the repaired LED chip to move above the driving back plate, and aligning the repaired LED chip with the region to be repaired.
The transfer head will then move the LED chip 71 to be repaired above the driving backplane 700c, and the position of the repaired LED chip 71 is aligned with the region to be repaired on the driving backplane 700c, as shown in fig. 7 (g).
S610: and melting the bonding layer for repairing by adopting a hot pressing process to bond and repair the LED chip and the driving backboard.
Subsequently, the transfer head carries the repair LED chip 71 to be close to the driving back plate 700c, and the thermal compression process is used to melt the bonding layer 72 for repair on the electrode of the repair LED chip 71, so as to bond the repair LED chip 71 to the driving back plate 700c, as shown in fig. 7 (h).
It should be understood that, since the height of the qualified retained LED chip 73 is the same as the height of the repaired LED chip 71, and the initial bonding layer under the electrode of the defective LED chip is retained when the defective LED chip is removed, in general, as long as the bonding layer 72 for repairing is added, the sum of the thickness of the bonding layer 72 for repairing and the height of the repaired LED chip 71 can be greater than the height of the qualified retained LED chip 73, so that the transfer head can apply a pressure towards the driving backplane 700c to the repaired LED chip 71, which not only improves the bonding reliability of the repaired LED chip 71, but also avoids the problem that the qualified retained LED chip is damaged.
Yet another alternative embodiment:
this embodiment will be described with reference to the flow chart and the process status diagram shown in fig. 8 and fig. 9, wherein:
s802: and after the defective LED chips on the driving backboard are removed, paving ACF on one side of the driving backboard, which is provided with qualified reserved LED chips, as a bonding layer for repairing.
After the dead LED chips are removed, the remaining LED chips on the driving back plate 900a are qualified LED chips 93, as shown in fig. 9 (a).
In this embodiment, only one ACF 92 is disposed as a bonding layer for repairing in all regions to be repaired on the driving backplane 900a, as shown in fig. 9 (b), the ACF 92 can cover all regions to be repaired, and it can be ensured that the area of the ACF 92 can still cover all regions to be repaired after the repair LED chip 91 drives the ACF 92 to move toward the driving backplane.
S804: and transferring the repaired LED chip to a temporary storage substrate.
The repaired LED chip 91 in this embodiment is the same size as the qualified reserved LED chip 93 that has been transferred onto the driving back plate 900a, and both have the same height.
In some examples, one side of the temporary storage substrate 900b is provided with a photoresist layer, and the side of the temporary storage substrate 900b provided with the photoresist layer may be used to approach the repair LED chip 91 on the growth substrate, as shown in fig. 9 (c), until the repair LED chip 91 is adhered to the photoresist layer, and then, the repair LED chip 91 and the growth substrate are peeled off by laser peeling, so that the repair LED chip 91 is transferred to the temporary storage substrate 900b, as shown in fig. 9 (d).
S806: and controlling the transfer head to selectively pick up the repaired LED chips from the temporary storage substrate according to the arrangement of the areas to be repaired on the driving backboard.
While the transfer head is used to suck the repair LED chips 91 to be picked up, the repair LED chips 91 selected by the transfer head are peeled off from the temporary storage substrate 900b by using laser, so that the transfer head picks up the repair LED chips 91, as shown in fig. 9 (e) and 9 (f).
S808: and controlling the transfer head to carry the repaired LED chip to move above the driving back plate, and aligning the repaired LED chip with the region to be repaired.
Then the transfer head moves the LED chip 91 to the position above the driving backplane 900a, and the position of the LED chip 91 is aligned with the region to be repaired on the driving backplane 900a, as shown in fig. 9 (g).
S810: and applying pressure towards the driving backboard to the repaired LED chip through the transfer head, so that the repaired LED chip drives the ACF to move towards the area to be repaired until the repaired LED chip is successfully bonded with the driving backboard.
In this embodiment, the successful bonding of the repair LED chip 91 and the driving backplane 900a means that the repair LED chip 91 and the region to be repaired are bonded together by the ACF 92, as shown in fig. 9 (h), and meanwhile, the insulating film covering the conductive particles in the ACF 92 is broken, so that the ACF 92 has conductivity.
S812: and (3) placing the driving back plate in an NMP solution, removing redundant ACF by using the NMP solution, and cleaning and drying the driving back plate.
In the present embodiment, an NMP solution is used as the ACF removal solution, and the excess ACF is removed by reacting with the NMP solution. The ACF for bonding the repair LED chip 91 should be retained for shielding the repair LED chip 91, as shown in fig. 9 (i).
In the LED repairing method provided by this embodiment, the ACF is disposed on the driving backplane as the bonding layer for repairing, so that the reliability of bonding between the repaired LED chip and the driving backplane is improved, the problem of the LED chip being qualified and remaining damaged in the LED repairing process is avoided, the bonding between the repaired LED chip and the driving backplane by using an excessively high temperature is also avoided, the LED chip on the driving backplane is protected, the repairing effect is enhanced, and the quality of the display screen is improved.
In the present application, the LED is a Micro light emitting diode (Micro-LED).
It will be understood that the invention is not limited to the examples described above, but that modifications and variations will occur to those skilled in the art in light of the above teachings, and that all such modifications and variations are considered to be within the scope of the invention as defined by the appended claims.

Claims (10)

1. An LED repairing method, comprising:
after removing a defective LED chip on a driving backboard, additionally arranging a bonding layer for repairing on a repairing bonding area, wherein the repairing bonding area is an area where the repairing LED chip is bonded with the driving backboard, and the sum of the thickness of the bonding layer for repairing and the height of the repairing LED chip is greater than the height of the qualified reserved LED chip on the driving backboard;
controlling a transfer head to pick up the repaired LED chip and aligning the repaired LED chip with a region to be repaired on the driving backboard, wherein the region to be repaired is a region on the driving backboard for deploying the repaired LED chip;
applying pressure towards the driving backboard to the repair LED chip through the transfer head so as to bond the repair LED chip to the driving backboard by using the bonding layer for repairing.
2. The LED repair method of claim 1, wherein the repair bonding region is located on an electrode of the repair LED chip, and the adding of the repair bonding layer on the repair bonding region comprises: and arranging a bonding layer for repairing on the electrode of the repaired LED chip.
3. The LED repairing method according to claim 2, wherein the providing of the bonding layer for repairing on the electrode of the repaired LED chip comprises:
and evaporating a metal layer with the melting point lower than 200 ℃ on the electrode of the repaired LED chip to form the bonding layer for repairing.
4. The LED repair method of any of claims 1-3, wherein the repair bonding area is located on the driving backplane, and the adding a repair bonding layer on the repair bonding area comprises: and additionally arranging a bonding layer for repairing in the region to be repaired of the driving backboard.
5. The LED repairing method according to claim 4, wherein the adding of the bonding layer for repairing in the region to be repaired of the driving backboard comprises:
paving an Anisotropic Conductive Film (ACF) as a bonding layer for repairing on one side of the driving backboard, which is provided with the qualified reserved LED chip, wherein the ACF covers the region to be repaired, and the area of the ACF is larger than that of the region to be repaired;
the applying, by the transfer head, a pressure toward the driving backplane to the repair LED chip to bond the repair LED chip to the driving backplane with the bonding layer for repair includes:
applying pressure towards the driving backboard to the repaired LED chip through a transfer head, so that the repaired LED chip drives the ACF to move towards the area to be repaired until the repaired LED chip and the area to be repaired are bonded together through the ACF, and the insulating film covering the conductive particles in the ACF is broken.
6. The LED repair method of claim 5, wherein after bonding the repair LED chip to the driving back plate using the bonding layer for repair, further comprising:
placing the driving back plate in an N-methylpyrrolidone (NMP) solution, and removing redundant ACF by using the NMP solution;
and cleaning and drying the driving back plate.
7. A display screen, comprising:
driving the back plate; and
the LED chips are arranged on the driving back plate and electrically connected with the driving circuit in the driving back plate;
the LED chips comprise repaired LED chips and qualified reserved LED chips which are not repaired; a bonding layer for repairing is arranged between the repairing LED chip and the driving backboard, and the bonding layer for repairing is used for bonding the repairing LED chip and the driving backboard; and the sum of the thickness of the bonding layer for repairing and the height of the repaired LED chip is greater than the height of the qualified reserved LED chip.
8. The display screen of claim 7, wherein the specifications of the repair LED chips are in accordance with the specifications of the qualified reserve LED chips.
9. A display screen as recited in claim 7 or 8, wherein the repairing bonding layer comprises at least one of a metal layer and ACF, the metal layer being composed of a metal having a melting point below 200 ℃.
10. An electronic device comprising a processor and a display screen according to any one of claims 7-9, the display screen being communicatively coupled to the processor.
CN202110604539.8A 2021-05-31 2021-05-31 LED repairing method, display screen and electronic equipment Pending CN115483337A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110604539.8A CN115483337A (en) 2021-05-31 2021-05-31 LED repairing method, display screen and electronic equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110604539.8A CN115483337A (en) 2021-05-31 2021-05-31 LED repairing method, display screen and electronic equipment

Publications (1)

Publication Number Publication Date
CN115483337A true CN115483337A (en) 2022-12-16

Family

ID=84419207

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110604539.8A Pending CN115483337A (en) 2021-05-31 2021-05-31 LED repairing method, display screen and electronic equipment

Country Status (1)

Country Link
CN (1) CN115483337A (en)

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