WO2023015569A1 - 微型元件结构及其制备方法、led芯片的转移方法 - Google Patents

微型元件结构及其制备方法、led芯片的转移方法 Download PDF

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Publication number
WO2023015569A1
WO2023015569A1 PCT/CN2021/112585 CN2021112585W WO2023015569A1 WO 2023015569 A1 WO2023015569 A1 WO 2023015569A1 CN 2021112585 W CN2021112585 W CN 2021112585W WO 2023015569 A1 WO2023015569 A1 WO 2023015569A1
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Prior art keywords
adhesive layer
pyrolytic
photolytic
adhesive material
micro
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PCT/CN2021/112585
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English (en)
French (fr)
Inventor
邓霞
萧俊龙
蔡明达
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重庆康佳光电技术研究院有限公司
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Priority to PCT/CN2021/112585 priority Critical patent/WO2023015569A1/zh
Priority to US17/720,674 priority patent/US12132032B2/en
Publication of WO2023015569A1 publication Critical patent/WO2023015569A1/zh

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    • 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
    • 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
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
    • 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
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • 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
    • H01L33/005—Processes
    • H01L33/0095—Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
    • 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

Definitions

  • the present application relates to the display field, in particular to a micro-element structure, a preparation method thereof, and a transfer method of LED chips.
  • Micro light-emitting diode (micro light-emitting diode, micro LED) display panel, as a new generation of display technology, has the advantages of higher brightness, better luminous efficiency and lower power consumption, making micro LED display panels are widely used.
  • Stamp transfer is one of the mainstream mass transfer technologies at present. Its general process is: 1) Bond multiple LED chips on the growth substrate to a temporary substrate with an adhesive layer, and then peel off the growth substrate to realize chip transfer onto the temporary substrate; 2) Then use the transfer substrate to press the LED chip, and use the laser to act on the adhesive layer on the temporary substrate to peel off the temporary substrate to realize the transfer of the chip to the transfer substrate; 3) Finally, the LED chip on the transfer substrate is transferred to the display backplane.
  • the laser usually also acts on the chip (especially its two electrodes) to cause certain damage to the chip and reduce the chip transfer yield.
  • the purpose of this application is to provide a temporary substrate and its preparation method, and a method for transferring LED chips, aiming to solve the problems of large damage to the chip by the laser and low chip transfer yield during the chip transfer process. .
  • the first aspect of the present application provides a micro-component structure, including: a substrate, a plurality of stacked adhesive layer structures arranged at intervals on the first surface of the substrate, corresponding to a plurality of LED chips arranged on the plurality of stacked adhesive layer structures
  • the surface of the LED chip facing the stacked adhesive layer structure has two lead-out electrodes;
  • the stacked adhesive layer structure includes a stacked photolytic adhesive layer and a thermal adhesive layer, and the photolytic adhesive layer is in contact with the first surface;
  • the pyrolytic glue layer is located between the two lead-out electrodes, and the thickness of the pyrolytic glue layer is greater than the height of the lead-out electrodes.
  • the dissociation and The laser energy required for the photolytic adhesive layer in the stacked adhesive layer structure connected by the LED chip is low, and the damage to the LED chip is small;
  • the pyrolytic adhesive layer, and its thickness is greater than the height of the lead-out electrode of the chip.
  • the thermal melting temperature of the pyrolytic adhesive layer is lower than the thermal melting temperature of the photolytic adhesive layer, and the difference between the thermal melting temperature of the thermal adhesive layer and the photolytic adhesive layer is greater than 20°C.
  • the photolytic adhesive material corresponding to the photolytic adhesive layer can be well keep its configuration unchanged.
  • the thickness of the pyrolytic adhesive layer is greater than the thickness of the photolytic adhesive layer.
  • the photolytic adhesive layer can be subsequently debonded by a laser with low energy, and the thermal debonding adhesive layer can block the laser irradiation damage to the LED chip during the debonding process of the photolytic adhesive layer.
  • the width of the photolytic adhesive layer is greater than or equal to the width of the thermal adhesive layer.
  • a photolytic adhesive layer is relatively easy to prepare, and the photolytic adhesive layer can better support the pyrolytic adhesive layer and the LED chip.
  • the second aspect of the present application provides a method for preparing a micro-element structure, including:
  • the stacked adhesive layer structure includes a photolytic adhesive layer and a pyrolytic adhesive layer, and the photolytic adhesive layer is distributed at intervals on the first surface; the thermal adhesive layer is located on the between the two lead-out electrodes of the LED chip, and the thickness of the pyrolytic glue layer is greater than the height of the lead-out electrodes.
  • the preparation method of the above-mentioned micro-element structure has simple process, convenient operation, and high controllability.
  • the stacked adhesive layer structure formed on the obtained micro-element structure can well solve the problem of laser damage to the LED chip during the transfer process of the LED chip on it.
  • the multiple stacked adhesive layer structures formed by two-step etching have high dimensional uniformity, which is convenient for subsequent batch debonding of the photolytic adhesive layers in the multiple stacked adhesive layer structures, avoiding problems caused by inconsistent unbonding time. Some chips are vulnerable to damage.
  • the method of removing the pyrolytic adhesive between two adjacent LED chips includes: wet etching or dry etching; wherein, the wet etching uses acetone and N-methylpyrrolidone At least one of them is used as an etching solution; the etching gas used in the dry etching includes oxygen.
  • wet etching or dry etching can realize vertical etching of the pyrolytic adhesive material along its surface away from the photolytic adhesive material.
  • the etching of the remaining pyrolytic adhesive material and the photolytic adhesive material is dry etching, and the dry etching includes first etching with oxygen for 10-20 min, and then using Fluorine gas etching for 5-8min.
  • the specific dry etching process used in this step has high controllability, and it is easier to form a stacked adhesive layer structure with a finer structure, and the obtained stacked adhesive layer structure has a high degree of uniformity in size, and is not easy to cause damage to the LED chip.
  • the third aspect of the present application provides a method for transferring LED chips, including:
  • micro-element structure as described in the first aspect of the present application, attach the transfer substrate to the side of the micro-element structure on which the LED chip is disposed, and irradiate the photoresist layer with laser, so that the LED chips and the pyrolytic adhesive layer are transferred to the transfer substrate;
  • the method for transferring the above-mentioned LED chip when transferring the LED chip from the micro-component structure with a special stacked adhesive layer structure to the transfer substrate, can use lower laser energy to dissociate the photolytic adhesive layer connected to the chip, and better Prevent the laser from irradiating the LED chip, thereby greatly reducing the damage of the laser to the chip during the chip transfer process and improving its transfer yield.
  • the pyrolytic adhesive layer connected to the chip can also play a role in improving the bonding force between the LED chip and the display backplane after thermal melting and cooling.
  • the transferring the LED chips on the transfer substrate to the display backplane includes: providing a plurality of solder joints on the side of the transfer substrate with the LED chips and the display backplane.
  • One side of the pad group is placed opposite, and the lead-out electrode is electrically connected to the pad group through thermal bonding. After cooling, the space between the lead-out electrode and the pad group is filled with the Pyrolytic adhesive layer; peeling off the transfer substrate.
  • the bonding force between the LED chip and the display backplane can be improved.
  • the fourth aspect of the present application provides a display device, including a display backplane and a plurality of LED chips, and the plurality of LED chips are transferred to the display backplane by the transfer method described in the third aspect of the application.
  • a stacking adhesive layer structure distributed on the substrate at intervals is provided between the substrate of the micro-component structure and the LED chip.
  • the stack connected to the LED chip is dissociated.
  • the laser energy required for the photolytic adhesive layer is relatively low, and the damage to the LED chip is small; , and its thickness is greater than the height of the lead-out electrode of the chip.
  • the pyrolytic adhesive layer can block the laser from irradiating the LED chip to a certain extent, further reducing the damage of the laser to the LED chip, thereby significantly improving the performance of the chip. transfer yield.
  • Figure 1 to Figure 6 show the common process of mass transfer of LED chips to the display backplane.
  • FIG. 7 to FIG. 13 are a flow chart of preparation of a micro-component structure provided by an embodiment of the present application.
  • 14 to 18 are schematic process flow diagrams of a method for transferring LED chips provided by an embodiment of the present application.
  • the LED chip 20 is transferred to the display backplane 100, the red LED chip, the blue LED chip and the green LED chip are respectively transferred.
  • the following takes one kind of LED chip 20 as an example for illustration, and the remaining two kinds of LED chips The same reason will not be repeated in this application.
  • FIG. 1 to Figure 6 show the common process of mass transfer of LED chips to the display backplane.
  • the specific process includes the following steps S11, S12 and S13.
  • Step S11 as shown in FIG. 1 , a growth substrate 10 (wafer) is provided, on which LED chips 20 are grown. Then, the side of the growth substrate 10 with the LED chip 20 is bonded to the side of the temporary substrate 30 with an adhesive layer (generally photolytic glue), and the LED chip 20 is bonded to the temporary substrate 30 (as shown in FIG. 2 ). Show). Next, the growth substrate 10 on the LED chip 20 is peeled off. Thus, the LED chip 20 can be transferred to the temporary substrate 30 , as shown in FIG. 3 .
  • an adhesive layer generally photolytic glue
  • Step S12 Use the transfer substrate 40 to press-bond the LED chips on the temporary substrate 30, and focus the laser light on the photoresist where the LED chips 20 to be picked up are connected (as shown in Figure 4), so that the LED chips under the corresponding LED chips The photoresist dissociates to realize the selective transfer of the LED chip 20 to the transfer substrate 40 .
  • FIG. 5 shows that the transfer substrate 40 selectively picks up the LED chips 20 from the temporary substrate 30 .
  • Step S13 Transfer the LED chips 20 on the transfer substrate 40 to the display backplane 50 .
  • FIG. 6 shows a schematic diagram showing successful transfer of the LED chip 20 on the backplane 50 .
  • the photolytic adhesive layer on the temporary substrate 30 generally covers the entire surface of the temporary substrate 30.
  • the photolytic adhesive layer is irradiated with laser light to realize the pickup of the LED chip 20 as shown in FIG.
  • the laser energy required to dissociate the photolytic adhesive adhesive layer corresponding to the LED chip 20 is generally high, and the laser will inevitably hit the lead-out electrode 21 of the LED chip 20, which may damage the LED chip 20 and cause its electrical sexual abnormalities will naturally reduce the transfer yield of the LED chip 20 .
  • FIG. 13 is a schematic structural diagram of a micro-element structure used in the LED chip transfer method provided by an embodiment of the present application.
  • FIG. 7 to FIG. 13 are a flow chart of preparation of a micro-component structure provided by an embodiment of the present application. Wherein, the preparation method of the micro-element structure includes the following steps S110-S150.
  • S110 Provide a substrate 300 , referring to FIG. 7 , and sequentially prepare a layered photolytic adhesive material 31 and a pyrolytic adhesive material 32 on the first surface 300 a of the substrate 300 .
  • the substrate 300 has two opposite surfaces, where the first surface 300a refers to the surface on which the photolytic adhesive material 31 and the pyrolytic adhesive material 32 are to be disposed. As shown in FIG. 7 , the photolytic adhesive material 31 is continuously distributed on the first surface 300 a of the substrate 300 , which can completely cover the first surface 300 a of the substrate 300 . Correspondingly, the pyrolytic adhesive material 32 can also be continuously distributed on the photolytic adhesive material 31 , which can completely cover the surface of the photolytic adhesive material 31 away from the substrate 300 .
  • the photolytic adhesive material 31 can be degummed due to the reduction of viscosity under the irradiation of laser with a predetermined wavelength, and the pyrolytic adhesive material can recover its viscosity after cooling.
  • the pyrolytic glue material 32 can be degummed due to the decrease in viscosity when heated to a predetermined temperature. The pyrolytic adhesive 32 does not react with laser light.
  • the photolytic adhesive material 31 and the pyrolytic adhesive material 32 can be prepared by a coating method, which can be independently selected from any one of spin coating, brush coating, spray coating, and the like. After the photolytic adhesive material 31 is coated, it needs to be cured, and then the pyrolytic adhesive material 32 is coated on it and cured.
  • the thickness of the photoresist material 31 may be in the range of 2 ⁇ m-3 ⁇ m.
  • the photolytic adhesive material 31 with a suitable thickness can not only provide a good support for the LED chip (as shown in FIG. 13 ), but also facilitate the subsequent degumming by a laser with low energy.
  • the thermal melting temperature of the pyrolytic adhesive material 32 is lower than the thermal melting temperature of the photolytic adhesive material 31 .
  • the difference between the melting temperatures of the pyrolytic adhesive material 32 and the photolytic adhesive material 31 may be greater than or equal to 20°C. At this time, the difference between the melting temperatures of the two adhesive materials is appropriate, and when the pyrolytic adhesive material 32 melts, the photolytic adhesive material 31 can well maintain its configuration.
  • S120 As shown in FIG. 8 , perform thermal bonding on the growth substrate 10 on which a plurality of LED chips 20 are grown and the substrate 300 , so that the LED chips 20 are embedded in the pyrolytic adhesive material 32 , and the two lead-out electrodes of the LED chips 20 21 toward the photoresist material 31 (as shown in FIG. 9 ), and then peel off the growth substrate 10 (as shown in FIG. 10 ), to obtain the structure as shown in FIG. 11 .
  • step S120 during thermal bonding, the side of the growth substrate 10 with the LED chip 20 and the side of the substrate 300 with the pyrolytic adhesive 32 can be bonded together by a bonding device, and then heated and pressed Next, the LED chip 20 is embedded in the pyrolytic adhesive material 32 .
  • the thermal bonding temperature should be greater than or equal to the melting temperature of the pyrolytic adhesive material 32 , so that the pyrolytic adhesive material 32 can be heated and melted to realize the connection between the growth substrate 10 and the photolytic adhesive material 31 .
  • the thermal bonding temperature should be lower than the melting temperature of the photolytic adhesive material 31 to prevent the photolytic adhesive material 31 from being melted and deformed during thermal bonding.
  • the thickness of the above pyrolytic adhesive material 32 should be greater than or equal to the height of the LED chip 20 .
  • the surface of the pyrolytic adhesive material 32 facing away from the photolytic adhesive material 31 may be flush with the surface of the LED chip 20 facing away from the photolytic adhesive material 31 .
  • a plurality of LED chips 20 are arranged in an array on the growth substrate 10 , and there is an interval between any two adjacent LED chips 20 .
  • Each LED chip 20 generally has two electrodes 21, which are generally a positive electrode and a negative electrode, so as to be subsequently connected to the positive and negative pads on the display backplane correspondingly.
  • the growth substrate 10 is generally gallium-containing sapphire.
  • the above-mentioned lift-off of the growth substrate 10 may be performed by laser lift-off (LLO, Laser Lift Off) technology.
  • dilute hydrochloric acid is used to wash away the residual gallium metal on the LED chip 20 .
  • the stacked glue layer structure includes a photolytic glue layer 31' and a pyrolytic glue layer 32', and the photolytic glue layer 31' is distributed on the first surface of the substrate 300 at intervals; the pyrolytic glue layer 32' is located on the LED chip 20 between the two lead-out electrodes 21 , and the thickness of the pyrolytic glue layer 32 ′ is greater than the height of the lead-out electrodes 21 .
  • the method of removing the pyrolytic adhesive 32 between two adjacent LED chips 20 may include wet etching or dry etching.
  • the wet etching may use acetone, N-methylpyrrolidone (NMP), or a mixture of acetone and NMP as an etchant.
  • the etching solution can be coated on the surface of the pyrolytic adhesive material 32 facing away from the photolytic adhesive material 31 in FIG.
  • the selective etching of the pyrolytic adhesive material 32 between two adjacent LED chips 20 can be realized, that is, etching is performed along the surface perpendicular to the pyrolytic adhesive material 32 away from the photolytic adhesive material 31 (abbreviated as vertical etching), that is, etching is performed along the thickness direction of the pyrolytic adhesive material 32 .
  • etching is performed along the surface perpendicular to the pyrolytic adhesive material 32 away from the photolytic adhesive material 31 (abbreviated as vertical etching), that is, etching is performed along the thickness direction of the pyrolytic adhesive material 32 .
  • ethanol, water, etc. should be used to rinse the structure shown in FIG. 12 , so as to prevent the remaining etching solution from affecting the next step of etching.
  • the dry etching can use etching gas to vertically etch the pyrolytic glue 32 between two adjacent LED chips 20 .
  • the inverted LED chip 20 can still serve as a mask for dry etching, and no additional mask is needed.
  • the etching gas can be directed toward the surface of the pyrolytic adhesive material 32 facing away from the photolytic adhesive material 31 in FIG. 11 .
  • the etching gas may be oxygen (O 2 ).
  • the etching performed on the remaining pyrolytic adhesive material 32 and photolytic adhesive material 31 is dry etching.
  • dry etching is more controllable, and it is easier to form a finer microstructure, and it is less likely to cause damage to the LED chip, and the resulting stacked adhesive layer structure has a high degree of uniformity in size.
  • the dry etching includes first etching with oxygen for 10-20 min, and then etching with fluorine-containing gas for 5-8 min.
  • the fluorine-containing gas may be at least one of CF 4 and SF 6 , etc., for example, it may be CF 4 , or SF 6 , or a mixture of CF 4 and SF 6 . Because the etching rate of fluorine-containing gas is generally higher than that of oxygen, the etching time of fluorine-containing gas is shorter than that of oxygen, which can ensure a product with a higher degree of matching with the required microstructure.
  • the flow rate ratio of oxygen to fluorine-containing gas may be (5-40):1, such as 10:1, 15:1, 20:1, 25:1, 30:1, or 40:1.
  • step S130 the temperature of the chamber where the substrate is located is lower than the thermal melting temperature of the pyrolytic adhesive material 32, so that the pyrolytic adhesive material 32 and the photolytic adhesive material 31 are in the etching process. No melting occurs, and the desired microstructure is obtained after etching.
  • the micro-component structure shown in FIG. 13 includes a substrate 300, a plurality of stacked adhesive layer structures and a plurality of LED chips 20, wherein the plurality of stacked adhesive layer structures are distributed on the first surface 300a of the substrate 300 at intervals, and the LED chips 20 is located on the stacked glue layer structure, a plurality of LED chips 20 correspond to the stacked glue layer structures one by one, and each LED chip 20 has two lead-out electrodes 21 on the surface facing the stacked glue layer structure.
  • the stacked adhesive layer structure includes a stacked photolytic adhesive layer 31' and a pyrolytic adhesive layer 32', and the photolytic adhesive layer 31' is in contact with the first surface 300a; the thermal adhesive layer 32' is located on both sides of the LED chip 20 between the two lead-out electrodes 21, and the thickness of the pyrolytic glue layer 32' is greater than the height of the lead-out electrodes 21.
  • the meaning of “one-to-one correspondence” here is: each stacked adhesive layer structure is connected to one LED chip 20 , and the number of stacked adhesive layer structures is consistent with the number of LED chips 20 .
  • the photoresist layer 31' is not continuously distributed on the first surface 300a, but distributed at intervals, and the number thereof is consistent with the number of LED chips 20. Compared with the substrate covered with the photoresist layer, the total coverage of the photoresist layer 31' on the substrate 300 in this application is low. When it is necessary to transfer the LED chip on the micro-component structure shown in FIG. When transferring the substrate (see FIG.
  • the laser energy required to dissociate the photolytic adhesive layer 31' in the stacked adhesive layer structure connected to the LED chip 20 is relatively low, and accordingly the damage to the LED chip 20 is small; in addition, due to A pyrolytic adhesive layer 32' inserted between the two lead-out electrodes 21 of the chip is also provided between the LED chip 20 and the photolytic adhesive layer 31', and its thickness is greater than the height of the chip lead-out electrodes 21.
  • the pyrolytic adhesive layer 32' can block the laser from irradiating the LED chip 20, further reducing the damage of the laser to the LED chip 20, thereby significantly improving the transfer yield of the chip.
  • the thickness of the pyrolytic adhesive layer 32' is greater than the thickness of the photolytic adhesive layer 31'.
  • the photolytic adhesive layer 31' can be subsequently debonded by a laser with a low energy, and during the debonding process of the photolytic adhesive layer 31', the thermal debonding layer 32' can block the irradiation of the laser light on the LED chip 20 .
  • the thickness of the photoresist layer 31' is in the range of 2 ⁇ m-3 ⁇ m, such as 2.2 ⁇ m, 2.5 ⁇ m or 2.8 ⁇ m.
  • the photolytic adhesive layer 31' can play a good supporting role for the thermal adhesive layer 32' and the LED chip 20, and can facilitate subsequent degumming.
  • the thickness of the pyrolytic adhesive layer 32' is in the range of 4 ⁇ m-6 ⁇ m, such as 4.5 ⁇ m, 5 ⁇ m or 5.5 ⁇ m.
  • the width d2 of the pyrolytic adhesive layer 32' should be less than or equal to the width d2 between the two lead-out electrodes 21 of the LED chip 20. spacing.
  • the width d2 of the pyrolytic adhesive layer 32' can be in the range of 2 ⁇ m-6 ⁇ m, such as 2.5 ⁇ m, 3 ⁇ m, 4 ⁇ m or 5 ⁇ m.
  • the width d1 of the photolytic adhesive layer 31' is greater than or equal to the width d2 of the pyrolytic adhesive layer 32' (d1>d2 shown in FIG. 13 ).
  • the projection of the photo-adhesive layer 31' on the substrate 300 covers the projection of the thermal-adhesive layer 32' on the substrate 300.
  • This can help the photolytic adhesive layer 31' to better support the thermal adhesive layer 32' and the LED chip 20, and such a photolytic adhesive layer 31' is easier to realize through the above-mentioned etching process.
  • the width d1 of the photoresist layer 31' may be in the range of 4 ⁇ m-9 ⁇ m. Further, the width d1 of the photoresist layer 31' may also be smaller than or equal to the distance between the two lead-out electrodes 21 of the LED chip 20.
  • the distance between two adjacent photoresist layers 31' is 30 ⁇ m-40 ⁇ m. At this time, the total coverage of the photoresist layer 31' on the substrate 300 is low, which is convenient for subsequent laser disbonding.
  • the width d1 of the photoresist layer 31' may also be smaller than the width d2 of the pyrolytic layer 32'.
  • the larger width of the pyrolytic adhesive layer 32' on it can well block the laser from irradiating the LED chip 20 and greatly reduce the impact of the laser on the LED chip 20. Damage to chip 20 .
  • the preparation method of the above-mentioned micro-element structure provided by this application has simple process, convenient operation, and high controllability. Damage to the LED chip.
  • the multiple stacked adhesive layer structures formed by the two-step etching in the above step S130 have high uniformity, that is, the size difference of the stacked adhesive layer structures connected to each chip is small, which is convenient for subsequent processing of multiple stacked adhesive layers.
  • the photoresist layer 31 ′ in the layer structure is debonded in batches with the same laser energy, and the debonding time is similar, which avoids the problem that some chips are easily damaged due to inconsistent disbonding time.
  • the embodiment of the present application also provides a method for transferring LED chips (also referred to as a method for transferring LED chips), including the following steps S140 and S150.
  • S140 Provide the micro-component structure as described above in this application (as shown in FIG. 13 ) and provide a transfer substrate 40. Referring to FIG. 14, attach the transfer substrate 40 to the side of the micro-component structure with the LED chip 20 on it, Laser irradiation is performed on the photolytic adhesive layer 31 ′, so that the LED chips 20 and the thermal adhesive layer 32 ′ are transferred to the transfer substrate 40 (as shown in FIG. 15 ).
  • the transfer of the LED chips 20 in step S140 may be to transfer all the LED chips 20 on the micro-component structure to the transfer substrate 40, or to selectively transfer a part of the LED chips 20 to the transfer substrate 40 (or called selective pickup of chips).
  • the laser is focused on the micro-component structure by positioning the photolytic adhesive layer in the stacked adhesive layer structure connected to the LED chips to be picked up (it can be all chips, or some chips)
  • the photoresist layer 31' is irradiated with laser light to reduce its viscosity and debond, and the LED chip 20 is separated from the substrate 300, so that the LED chip 20 is transferred to the transfer substrate 40.
  • the viscosity of the thermal debonding layer 32 ′ hardly changes, therefore, the thermal debonding layer 32 ′ connected to the LED chip 20 is also transferred to the transfer substrate 50 accordingly.
  • the transfer substrate 40 bonded to the above-mentioned micro-element structure may have an adhesive layer, and the LED chips 20 may be selectively bonded to the transfer substrate 40 by means of the adhesive layer.
  • the material of the transfer substrate 40 may be polydimethylsiloxane (PDMS), polyurethane (PUA), ethylene-vinyl acetate copolymer (EVA), polymethylmethacrylate (PMMA) etc. one or more.
  • PDMS polydimethylsiloxane
  • PVA polyurethane
  • EVA ethylene-vinyl acetate copolymer
  • PMMA polymethylmethacrylate
  • the transfer substrate 40 has a certain degree of viscosity, and it is not necessary to provide an adhesive layer on the transfer substrate 40 , and it satisfies the above-mentioned characteristics of adhesive force.
  • PDMS is the most common material for the transfer substrate 40 .
  • step S150 specifically includes:
  • S151 As shown in FIG. 16 , place the side of the transfer substrate 40 with the LED chip 20 opposite to the side of the display backplane 50 provided with a plurality of pad groups 51, and thermally bond the side of the LED chip 20.
  • the lead-out electrode 21 is electrically connected to the pad group 51 correspondingly, and after cooling, the space between the lead-out electrode 21 and the pad group 51 is filled with a pyrolytic glue layer 32 ′, as shown in FIG. 17 ;
  • step S151 when the transfer substrate 40 and the display backplane 50 are placed facing each other, the transfer substrate 40 can be suspended above the display backplane 50 so that the plurality of LED chips 20 and the plurality of LED chips 20 on the display backplane 50 There is a one-to-one correspondence between the pad groups 51 .
  • the display backplane 50 may be a thin film transistor (Thin Film Transistor, TFT) circuit board.
  • TFT Thin Film Transistor
  • each pad group 51 is used for subsequent electrical connection with the two lead-out electrodes 21 (that is, the positive lead-out electrode and the negative lead-out electrode) of the LED chip 20, each pad group 51 includes two pads , can be called positive pad, negative pad.
  • the positive lead-out electrode of each LED chip 20 corresponds to a positive pad
  • the negative lead-out electrode corresponds to a negative pad.
  • thermal bonding in S151 it may be performed by pressurizing and heating the transfer substrate 40 and the display backplane 50 .
  • the lead-out electrode 21 of the LED chip 20 is fixedly connected to the pad group 51 of the display backplane 50, and the stability of the electrical connection between the two is guaranteed. welding.
  • pressure can be applied on the surface of the transfer substrate 40 away from the LED chips 20 (as shown in FIG.
  • the bonded structure is placed in a heated environment.
  • the above-mentioned transfer substrate 40 can be made of soft material such as PDMS, which has a certain deformation ability, it can prevent the LED chip 20 from being crushed when pressure is applied to it.
  • the pyrolytic glue layer 32' is greater than the height of the chip electrodes, the pyrolytic glue layer 32' can also be inserted between a pair of pads of the display backplane 50, and it can be melted by heat, and filled in after cooling.
  • the space between the lead-out electrode 21 and the pad group 51 further strengthens the bonding force between the LED chip 20 and the display backplane 50, and it is not necessary to additionally coat the display backplane 50 with an adhesive material like some prior art To strengthen its bonding force with the chip.
  • the thermal bonding temperature in step S151 should be greater than or equal to the thermal melting temperature of the pyrolytic adhesive layer 32'.
  • pressure can also be applied simultaneously on the surface of the transfer substrate 40 facing away from the LED chip 20 and the surface of the display backplane 50 that is not provided with the pad group 51, so that the two are bonded together, and the two Or the bonded structure is placed in a heated environment.
  • the peeling of the transfer substrate 40 in step S152 may be performed by mechanical peeling. This is mainly because the bonding force between the LED chip 20 and the display backplane 50 is stronger than the bonding force between the transfer substrate 40 and the LED chip 20 .
  • This method of peeling off the transfer substrate 40 is relatively simple. Certainly, if the transfer substrate 40 has an adhesive layer on it as shown in the above step S140 , peeling off the transfer substrate 40 can be achieved by debonding the adhesive layer between the transfer substrate 40 and the LED chips 20 .
  • the LED chip transfer method can transfer the LED chip 20 from the micro-component structure to the transfer substrate 40 by using the micro-component structure with a special stacked adhesive layer structure.
  • the low-energy laser can realize the debonding of the photolytic adhesive layer 31' connected to the chip, and the thermal adhesive layer 32' can also prevent the laser from irradiating the LED chip 20, thereby greatly reducing the cost of transferring the LED chip 20 by laser.
  • the damage to the chip during the process can significantly improve the transfer yield of the chip.
  • the pyrolytic adhesive layer 32' can also better fill the lead-out electrodes of the chips and the pads on the display backplane after thermal melting and cooling.
  • the gap between the groups further improves the bonding force between the LED chip 20 and the display backplane 50 . Therefore, the method for transferring the above-mentioned LED chip provided by the embodiment of the present application is simple, convenient to operate, has a high transfer yield of the LED chip, and has a strong bonding force between the LED chip and the display backplane.
  • the embodiment of the present application also provides a display device, which specifically includes a display backplane 50 and a plurality of LED chips 20, wherein the LED chips 20 adopt the above-mentioned
  • the transfer method provided by any embodiment is transferred to the display backplane 50 .
  • the display device can be an LED display panel, and equipment such as televisions, computers and industrial computers using the LED display panel.

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Abstract

一种微型元件结构及其制备方法、LED芯片的转移方法，其中微型元件结构包括衬底(300)、间隔设置在衬底(300)的第一表面(300a)上的多个堆叠胶层结构和对应设置在多个堆叠胶层结构上的多个LED芯片(20)，LED芯片(20)朝向堆叠胶层结构的表面具有两个引出电极(21)；堆叠胶层结构包括层叠设置的光解胶层(31')和热解胶层(32')，光解胶层(31')与第一表面(300a)接触，热解胶层(32')位于两个引出电极(21)之间，且热解胶层(32')的厚度大于引出电极(21)的高度。

Description

微型元件结构及其制备方法、LED芯片的转移方法 技术领域
本申请涉及显示领域，尤其涉及一种微型元件结构及其制备方法、LED芯片的转移方法。
 背景技术
微型发光二极管（micro light-emitting diode，micro LED）显示面板作为新一代显示技术，具有亮度更高、发光效率更好以及功耗更低等优势，使得micro LED显示面板被广泛使用。
在micro LED显示面板的制备过程中，需要通过巨量转移技术将三色LED芯片从各自的生长基板上转移到显示背板上。印章式转移是目前主流的巨量转移技术之一，其一般过程为：1）将生长基板上的多个LED芯片粘合到带粘附层的临时基板上，然后剥离生长基板，实现芯片转移到临时基板上；2）接着利用转移基板压合LED芯片，通过激光作用于临时基板上的粘附层来剥离临时基板而实现芯片转移至转移基板；3）最后该转移基板上的LED芯片转移到显示背板上。然而，在上述步骤2）的转移过程中，激光通常也会作用在芯片上（特别是其两电极上）而对芯片造成一定损伤，降低芯片转移良率。
 技术问题
鉴于上述现有技术的不足，本申请的目的在于提供一种临时基板及其制备方法、LED芯片的转移方法，旨在解决芯片转移过程中激光对芯片的损伤大、芯片转移良率低的问题。
 技术解决方案
本申请第一方面提供一种微型元件结构，包括：衬底，间隔设置在衬底的第一表面上的多个堆叠胶层结构，对应设置在多个堆叠胶层结构上的多个LED芯片，LED芯片朝向堆叠胶层结构的表面具有两个引出电极；堆叠胶层结构包括层叠设置的光解胶层和热解胶层，且所述光解胶层与所述第一表面接触；所述热解胶层位于两个所述引出电极之间，且所述热解胶层的厚度大于所述引出电极的高度。
本申请中，通过在微型元件结构的衬底与LED芯片之间设置间隔分布在衬底上的堆叠胶层结构，当需要将该微型元件结构上的LED芯片转移至转移基板时，解离与LED芯片连接的堆叠胶层结构中光解胶层所需的激光能量较低，对LED芯片的损伤小；且由于LED芯片与光解胶层之间还设置有插入在芯片两引出电极之间的热解胶层，且其厚度大于芯片引出电极高度，当采用激光解离光解胶层时，该热解胶层可在一定程度上阻挡激光照射到LED芯片上，进一步减少激光对LED芯片的损伤，从而显著提高芯片的转移良率。
可选地，所述热解胶层的热熔温度低于所述光解胶层的热熔温度，所述热解胶层与所述光解胶层的热熔温度之差大于20℃。这样，在该微型元件结构的制备过程中，通过热解胶层材料的熔化实现LED芯片的两电极之间嵌有热解胶层时，光解胶层对应的光解胶材能很好地保持其构型不变。
可选地，所述热解胶层的厚度大于所述光解胶层的厚度。这样，所述光解胶层后续可通过能量不是很高的激光进行解胶，且热解胶层能在光解胶层的解胶过程中阻挡激光对LED芯片的照射损伤。
可选地，所述光解胶层的宽度大于或等于所述热解胶层的宽度。这样的光解胶层较易制备，且该光解胶层能较好地支撑热解胶层和LED芯片。
本申请第二方面提供了一种微型元件结构的制备方法，包括：
在衬底的第一表面上依次制备层叠设置的光解胶材和热解胶材；
将生长有多个LED芯片的生长基板与所述衬底进行热键合，使所述LED芯片嵌入所述热解胶材中，且所述LED芯片的两个引出电极朝向所述光解胶材；
剥离所述生长基板；
去除相邻两个所述LED芯片之间的热解胶材，对剩下的热解胶材及所述光解胶材进行刻蚀，以在所述衬底和所述LED芯片之间形成堆叠胶层结构；其中，所述堆叠胶层结构包括光解胶层和热解胶层，且所述光解胶层在所述第一表面上间隔分布；所述热解胶层位于所述LED芯片的两个引出电极之间，且所述热解胶层的厚度大于所述引出电极的高度。
上述微型元件结构的制备方法，工艺简单、操作便捷，可控度高，所得微型元件结构上形成的堆叠胶层结构能很好地解决其上的LED芯片在转移过程中激光对LED芯片的损伤。此外，通过两步刻蚀形成的多个堆叠胶层结构的尺寸均一性高，便于后续对多个堆叠胶层结构中的光解胶层进行批量解胶，避免了因解胶时间不一致带来的某些芯片易损伤的问题。
可选地，去除相邻两个所述LED芯片之间的热解胶材的方式包括：湿法刻蚀或者干法刻蚀；其中，所述湿法刻蚀采用丙酮和N-甲基吡咯烷酮中的至少一种作为刻蚀液；所述干法刻蚀采用的刻蚀气体包括氧气。由此，借助LED芯片的掩膜，湿法刻蚀或者干法刻蚀均能对热解胶材实现沿其背离光解胶材的表面的垂直刻蚀。
可选地，对剩下的热解胶材及所述光解胶材进行的所述刻蚀为干法刻蚀，所述干法刻蚀包括先采用氧气刻蚀10-20min，再采用含氟气体刻蚀5-8min。该步采用的特定干法刻蚀工艺的可控性高，较易形成结构较精细的堆叠胶层结构，且所得堆叠胶层结构的尺寸均一度高，并不易对LED芯片造成破坏。
本申请第三方面提供了一种LED芯片的转移方法，包括：
提供如本申请第一方面所述的微型元件结构，将转移基板贴合至所述微型元件结构设置有所述LED芯片的一侧，对所述光解胶层进行激光照射，以使所述LED芯片和所述热解胶层转移到所述转移基板；
将所述转移基板上的所述LED芯片转移至显示背板。
上述LED芯片的转移方法，通过从带特殊堆叠胶层结构的微型元件结构上转移LED芯片至转移基板时，可采用较低的激光能量解离与芯片连接的光解胶层，且较好地阻挡激光照射到LED芯片上，从而大大减少芯片转移过程中激光对芯片的损伤，提高其转移良率。此外，当转移基板上的LED芯片转移至显示背板时，与芯片连接的热解胶层还可在热熔化、冷却后起到提高LED芯片和显示背板之间的键合力的作用。
可选地，所述将所述转移基板上的所述LED芯片转移至显示背板，包括：将所述转移基板带有所述LED芯片的一侧与所述显示背板设有多个焊盘组的一侧对向放置，经热键合，使所述引出电极与所述焊盘组对应电连接，冷却后，所述引出电极与所述焊盘组之间的空间填充有所述热解胶层；剥离所述转移基板。由此，可提高LED芯片与显示背板之间的结合力。
本申请第四方面提供了一种显示装置，包括显示背板和多个LED芯片，多个LED芯片通过本申请第三方面所述的转移方法转移至显示背板上。
 有益效果
上述微型元件结构的衬底与LED芯片之间设置间隔分布在衬底上的堆叠胶层结构，当需要将该微型元件结构上的LED芯片转移至转移基板时，解离与LED芯片连接的堆叠胶层结构中光解胶层所需的激光能量较低，对LED芯片的损伤小；且由于LED芯片与光解胶层之间还设置有插入在芯片两引出电极之间的热解胶层，且其厚度大于芯片引出电极高度，当采用激光解离光解胶层时，该热解胶层可在一定程度上阻挡激光照射到LED芯片上，进一步减少激光对LED芯片的损伤，从而显著提高芯片的转移良率。
 附图说明
图1至图6示出了LED芯片巨量转移至显示背板的常见流程。
图7至图13为本申请一实施例提供的微型元件结构的一种制备流程图。
图14至图18是本申请一实施例提供的LED芯片的转移方法的工艺流程示意图。
附图标记说明：10-生长基板，20-LED芯片，21-引出电极，30-临时基板，40-转移基板，50-显示背板，51-焊盘组，300-衬底，300a-第一表面，31-光解胶材，32-热解胶材，31’-光解胶层，32’-热解胶层。
 本发明的实施方式
为了便于理解本申请，下面将参照相关附图对本申请进行更全面的描述。附图中给出了本申请的较佳实施方式。但是，本申请可以以许多不同的形式来实现，并不限于本文所描述的实施方式。相反地，提供这些实施方式的目的是使对本申请的公开内容理解的更加透彻全面。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是旨在于限制本申请。
一般情况下，LED芯片20转移至显示背板100上时，分别将红色LED芯片、蓝色LED芯片和绿色LED芯片进行转移，下面以一种LED芯片20为例进行说明，其余两种LED芯片同样的道理，本申请中不再赘述。
图1至图6示出了LED芯片巨量转移至显示背板的常见流程。具体过程包括如下步骤S11、S12和S13。
步骤S11：如图1所示，提供生长基板10（wafer），生长基板10上生长有LED芯片20。然后将生长基板10带有LED芯片20的一侧与临时基板30带粘附层（一般是光解胶）的一侧贴合，将LED芯片20粘合到临时基板30上（如图2所示）。接着剥离LED芯片20上的生长基板10。由此可以将LED芯片20转移至临时基板30上，如图3所示。
步骤S12：利用转移基板40压合临时基板30上的LED芯片，并将激光聚焦到所需拾取的LED芯片20连接的光解胶处（如图4所示），以将对应LED芯片下的光解胶解离，实现选择性地将LED芯片20转移到转移基板40上。图5示出了转移基板40从临时基板30上选择性地拾取LED芯片20。
步骤S13：将转移基板40上的LED芯片20转移至显示背板50上。参考图6，图6显示出显示背板50上成功转移LED芯片20的示意图。
由上述图3可知，临时基板30上的光解胶粘附层一般是整面覆盖在临时基板30上，当像图4中激光照射该光解胶粘附层以实现LED芯片20的拾取时，解离与LED芯片20对应的光解胶粘附层所需要的激光能量一般较高，且激光将不可避免地打到LED芯片20的引出电极21上，可能损伤LED芯片20，导致其电性异常，自然也会降低LED芯片20的转移良率。
基于此，本申请希望提供一种能够解决上述技术问题的方案，其详细内容将在后续实施例中得以阐述。
参考图7至图13，图13为本申请一实施例提供的LED芯片的转移方法所用的微型元件结构的一种结构示意图。图7至图13为本申请一实施例提供的微型元件结构的一种制备流程图。其中，该微型元件结构的制备方法包括以下步骤S110-S150。
S110：提供衬底300，参见图7，在衬底300的第一表面300a上依次制备层叠设置的光解胶材31和热解胶材32。
衬底300具有相对设置的两表面，这里的第一表面300a是指其上待设置光解胶材31和热解胶材32的表面。如图7所示，光解胶材31在衬底300的第一表面300a上连续分布，其可以完全覆盖衬底300的第一表面300a。相应地，热解胶材32也可以在光解胶材31上连续分布，其可以完全覆盖光解胶材31远离衬底300的表面。其中，光解胶材31可以在预设波长的激光照射下因粘度降低而解胶，冷却后热解胶材可以恢复粘性。热解胶材32可以在被加热至预设温度时，因粘度降低而解胶。热解胶材32不与激光反应。
光解胶材31和热解胶材32可以通过涂覆法制备，具体可以独立地选自旋涂、刷涂、喷涂等中的任意一种。在涂覆光解胶材31后，需待其固化后，再在其上涂覆热解胶材32，并固化。可选地，光解胶材31的厚度可以在2μm-3μm的范围。合适厚度的光解胶材31，既可后续对LED芯片起良好支撑作用（如图13）外，又便于后续通过能量不高的激光进行解胶。
本申请实施方式中，热解胶材32的热熔温度低于光解胶材31的热熔温度。这样，当后续通过热解胶材32实现衬底100与生长有LED芯片的生长基板的连接时，光解胶材31仍能保持形貌不变。在一些实施方式中，热解胶材32与光解胶材31的热熔温度之差可以大于或等于20℃。此时，两种胶材的热熔温度的差值较合适，在热解胶材32发生熔化时，光解胶材31能很好地保持其构型。
S120：如图8所示，将生长有多个LED芯片20的生长基板10与衬底300进行热键合，使LED芯片20嵌入热解胶材32中，且LED芯片20的两个引出电极21朝向光解胶材31（如图9所示），然后剥离生长基板10（如图10所示），得到如图11所示的结构。
步骤S120中，在进行热键合时，可以通过键合设备将生长基板10带有LED芯片20的一侧与衬底300带有热解胶材32的一侧相贴合，在加热加压下实现LED芯片20嵌入热解胶材32中。其中，热键合的温度应大于或等于热解胶材32的热熔温度，这样热解胶材32可受热熔化，实现生长基板10与带光解胶材31的连接。当然，热键合的温度应低于光解胶材31的热熔温度，以免热键合时光解胶材31发生熔化变形。
其中，为实现LED芯片20嵌入热解胶材32中，上述热解胶材32的厚度应大于或等于LED芯片20的高度。在一些实施方式中，热解胶材32背离光解胶材31的表面可以与LED芯片20背离光解胶材31的表面齐平。
一般地，多个LED芯片20在生长基板10上阵列排布，且任意相邻的两个LED芯片20之间均具有间隔。每个LED芯片20一般具有两个电极21，这两个电极一般是正电极和负电极，以便后续与显示背板上的正、负焊盘对应连接。生长基板10一般是含镓的蓝宝石。上述生长基板10的剥离可以通过激光剥离（LLO，Laser Lift Off）技术进行。可选地，并在剥离完成后，采用稀释的盐酸清洗掉LED芯片20上的残留金属镓。
S130：去除相邻两个LED芯片20之间的热解胶材32，得到如图12所示的结构，再对剩下的热解胶材32及光解胶材31进行刻蚀，以在衬底300和每个LED芯片20之间形成堆叠胶层结构，得到如图13所示的微型元件结构。其中，堆叠胶层结构包括光解胶层31’和热解胶层32’，且光解胶层31’与在衬底300的第一表面上间隔分布；热解胶层32’位于LED芯片20的两个引出电极21之间，且热解胶层32’的厚度大于引出电极21的高度。
步骤S130中，去除相邻两个LED芯片20之间的热解胶材32的方式，可以包括湿法刻蚀或者干法刻蚀。其中，所述湿法刻蚀可以采用丙酮、N-甲基吡咯烷酮（NMP）、或者丙酮和NMP的混合等作为刻蚀液。具体可以将该蚀刻液涂覆在图11中热解胶材32背离光解胶材31的表面，此时倒置的LED芯片20可充当湿法蚀刻的掩膜板，无需再额外引入掩膜板，就能实现对相邻两个LED芯片20之间的热解胶材32的选择性刻蚀，即，沿垂直于热解胶材32背离光解胶材31的表面进行刻蚀（简称为垂直刻蚀），也即沿热解胶材32的厚度方向进行刻蚀。可选地，在湿法刻蚀后，应采用乙醇、水等冲洗图12所示的结构，以免残留的刻蚀液影响下一步的刻蚀。
所述干法刻蚀可以采用刻蚀气体对位于相邻两个LED芯片20之间的热解胶材32进行垂直刻蚀。倒置的LED芯片20仍可充当干法蚀刻的掩膜板，无需再额外引入掩膜板。该刻蚀气体可正对着朝图11中热解胶材32背离光解胶材31的表面朝向通入。该刻蚀气体可以是氧气（O 2）。
步骤S130中，对剩下的热解胶材32及光解胶材31进行的刻蚀为干法刻蚀。干法刻蚀相较于湿法刻蚀的可控性高，较易形成较精细的微结构，且不易对LED芯片造成破坏，且所得堆叠胶层结构的尺寸均一度高。在一些实施方式中，该干法刻蚀包括先采用氧气刻蚀10-20min，再采用含氟气体刻蚀5-8min。其中，含氟气体可以是CF 4和SF 6等中的至少一种，例如可以是CF 4、或者SF 6、或者为CF 4和SF 6的混合。因含氟气体的刻蚀速率一般高于氧气，故而采用含氟气体的刻蚀时间短于采用氧气的刻蚀时间，可保证得到与所需微结构匹配度更高的产品。可选地，氧气与含氟气体的通入流量比可以为（5-40）:1，例如10:1、15:1、20:1、25:1、30:1或40:1等。此外，可以理解的，步骤S130的刻蚀过程中，基材所处的腔室温度低于热解胶材32的热熔温度，以便热解胶材32和光解胶材31在刻蚀过程中不发生熔化，经刻蚀后得到所需微结构。
图13示出的微型元件结构，包括衬底300、多个堆叠胶层结构和多个LED芯片20，其中，多个堆叠胶层结构间隔分布在衬底300的第一表面300a上，LED芯片20位于堆叠胶层结构上，多个LED芯片20与多个堆叠胶层结构一一对应，每个LED芯片20朝向堆叠胶层结构的表面具有两个引出电极21。其中，堆叠胶层结构包括层叠设置的光解胶层31’和热解胶层32’，且光解胶层31’与第一表面300a接触；热解胶层32’位于LED芯片20的两个引出电极21之间，且热解胶层32’的厚度大于引出电极21的高度。这里的“一一对应”的含义是：每个堆叠胶层结构上都连接有一个LED芯片20，堆叠胶层结构的数目与LED芯片20的数目一致。
由图13可知，光解胶层31’不是在第一表面300a连续分布，而是间隔分布，其数目与LED芯片20的数目一致。与整面覆盖有光解胶层的衬底相比，本申请中光解胶层31’在衬底300上的总覆盖率低，当需要将图13所示微型元件结构上的LED芯片转移至转移基板时（参见图14），解离与LED芯片20连接的堆叠胶层结构中光解胶层31’所需的激光能量较低，相应地对LED芯片20的损伤小；另外，由于LED芯片20与光解胶层31’之间还设置有插入在芯片两引出电极21之间的热解胶层32’，且其厚度大于芯片引出电极21高度，当采用激光解离光解胶层31’时，热解胶层32’可阻挡激光照射到LED芯片20上，进一步减少激光对LED芯片20的损伤，从而显著提高芯片的转移良率。
本申请实施方式中，热解胶层32’的厚度大于光解胶层31’的厚度。这样，光解胶层31’后续可通过能量不是很高的激光进行解胶，且在光解胶层31’的解胶过程中，热解胶层32’能阻挡激光对LED芯片20的照射。在一些实施方式中，光解胶层31’的厚度在2μm-3μm的范围内，例如为2.2μm、2.5μm或2.8μm等。此时，光解胶层31’可对热解胶层32’、LED芯片20起到良好支撑作用，且能便于后续解胶。在一些实施方式中，热解胶层32’的厚度在4μm-6μm的范围内，例如为4.5μm、5μm或5.5μm等。
可以理解的是，由于热解胶层32’位于LED芯片20的两个引出电极21之间，热解胶层32’的宽度d2应小于或者等于LED芯片20的两个引出电极21之间的间距。在一些实施方式中，热解胶层32’的宽度d2可以在2μm-6μm的范围内，例如为2.5μm、3μm、4μm或5μm等。本申请一些实施方式中，光解胶层31’的宽度d1大于或者等于热解胶层32’的宽度d2（图13中所示的是d1＞d2）。换句话说，光解胶层31’在衬底300上的投影覆盖热解胶层32’在衬底300上的投影。这样可有助于光解胶层31’较好地支撑热解胶层32’和LED芯片20，且这样的光解胶层31’较易通过上述刻蚀工艺实现。其中，光解胶层31’的宽度d1可以在4μm-9μm的范围内。进一步地，光解胶层31’的宽度d1也可以小于或者等于LED芯片20的两个引出电极21之间的间距。以便在激光解离光解胶层31’时减少激光照射到芯片电极上。可选地，相邻的两个光解胶层31’之间的间距是30μm-40μm。此时光解胶层31’在衬底300上的总覆盖率低，便于后续激光解胶。
当然，本申请另一些实施方式中，光解胶层31’的宽度d1还可以小于热解胶层32’的宽度d2。此时，当后续对光解胶层31’进行激光解胶时，位于其上的宽度较大的热解胶层32’能可好地阻挡激光照射到LED芯片20上而大大减少激光对LED芯片20的损伤。
本申请提供的上述微型元件结构的制备方法，工艺简单、操作便捷，可控度高，所得微型元件结构上形成的堆叠胶层结构能很好地解决其上的LED芯片在转移过程中激光对LED芯片的损伤。此外，其中上述步骤S130中通过两步刻蚀形成的多个堆叠胶层结构的均一性高，即，与每颗芯片相连的堆叠胶层结构的尺寸差异较小，便于后续对多个堆叠胶层结构中的光解胶层31’采用同样的激光能量进行批量解胶，且解胶时间相近，避免了因解胶时间不一致带来的某些芯片易损伤的问题。
本申请实施例还提供了一种LED芯片的转移方法（也可称为LED芯片的转移方法），包括以下步骤S140和S150。
S140：提供本申请如上所述的微型元件结构（如图13所示）及提供一转移基板40，参见图14，将该转移基板40贴合至微型元件结构上有LED芯片20的一侧，对光解胶层31’进行激光照射，以使LED芯片20和热解胶层32’转移到转移基板40（如图15所示）。
步骤S140中对LED芯片20的转移，可以是将微型元件结构上的LED芯片20全部转移到转移基板40上，也可以是将选择性地将一部分LED芯片20转移到转移基板40上（也可以称为对芯片的选择性拾取）。在转移LED芯片20的过程中，通过定位将激光聚焦到微型元件结构上与待拾取的LED芯片（可以是所有芯片，也可以是部分芯片）相连接的堆叠胶层结构中的光解胶层31’处，对该光解胶层31’进行激光照射以使其粘性降低而解胶，LED芯片20与衬底300分离，从而实现将LED芯片20转移到转移基板40上，由于在对光解胶层31’解胶的过程中，热解胶层32’的粘性几乎不会发生变化，因此，与LED芯片20相连的热解胶层32’也相应转移到转移基板50。
可以理解的是，当对微型元件结构上的LED芯片20进行选择性拾取时，为保证不需拾取的LED芯片20不被转移基板40带走，转移基板40应与LED芯片20之间有一定粘合力，且该粘合力应小于微型元件结构的衬底300与光解胶层31’之间的粘合力。在本申请一些实施方式中，与上述微型元件结构进行贴合的转移基板40上可以带有粘附层，可借助该粘附层选择性地将LED芯片20粘合到转移基板40上。在本申请另一些实施方式中，转移基板40的材质可以是聚二甲基硅氧烷（PDMS）、聚胺脂（PUA）、乙烯-醋酸乙烯共聚物（EVA）、聚甲基丙烯酸甲酯（PMMA）等中的一种或多种。此时，转移基板40有一定粘性，可不必在转移基板40设置粘附层，且其满足上述粘合力特征。一般地，转移基板40以PDMS最为常见。
S150：将转移基板40上的LED芯片20转移至显示背板50。
在一些实施方式中，步骤S150具体包括：
S151：如图16所示，将转移基板40带有LED芯片20的一侧与显示背板50设有多个焊盘组51的一侧对向放置，经热键合，使LED芯片20的引出电极21与焊盘组51对应电连接，冷却后，引出电极21与焊盘组51之间的空间填充有热解胶层32’，如图17所示；
S152：剥离转移基板40，得到如图18所示的产品。
步骤S151中，在将转移基板40与显示背板50进行对向放置时，可将转移基板40悬空设置于显示背板50的上方，使多个LED芯片20与显示背板50上的多个焊盘组51一一对应。其中，显示背板50可以为薄膜晶体管（Thin Film Transistor，TFT）电路板。显示背板50具有相对设置的两表面，其中一个表面上带有多个焊盘组51。由于该焊盘组51是用于后续与LED芯片20的两个引出电极21（即，正引出电极、负引出电极）进行对应的电连接，因此，每个焊盘组51包括两个焊盘，可称为正焊盘、负焊盘。在上述对向放置时，使每个LED芯片20的正引出电极对应一个正焊盘，负引出电极对应一个负焊盘。
在S151中进行热键合时，可以通过对转移基板40和显示背板50进行加压加热的方式进行。在热键合完成时，LED芯片20的引出电极21与显示背板50的焊盘组51完成了固定连接，二者的电连接稳定性得到保障，也可称为LED芯片20完成了巨量焊接。
在一些实施方式中，可以在转移基板40背离LED芯片20的表面施加压力（如图17所示），以使转移基板40与显示背板50相贴合，并对显示背板50进行加热或者将二者贴合后的结构置于加热环境中。由于上述转移基板40可以采用PDMS等软质材料，具有一定变形能力，在对其施加压力时，可防止压伤LED芯片20。且由于热解胶层32’的厚度大于芯片电极的高度，热解胶层32’也可插入到显示背板50的一对焊盘之间，且其可受热熔化，并在冷却后填充在引出电极21与焊盘组51之间的空间，进一步加固了LED芯片20和显示背板50之间的键合力，且不必像一些现有技术还在显示背板50上额外涂覆粘合材料来加固其与芯片的结合力。类似地，步骤S151中热键合的温度应大于或等于热解胶层32’的热熔温度。
当然，在本申请另一些实施方式中，还可以在转移基板40背离LED芯片20的表面及显示背板50未设置焊盘组51的表面同时施加压力，以使二者贴合，并将二者贴合后的结构置于加热环境中。
本申请一些实施方式中，步骤S152中剥离转移基板40，可以通过机械剥离的方式进行。这主要是基于LED芯片20与显示背板50之间的结合力强于转移基板40与LED芯片20之间的粘合力。此种剥离转移基板40的方式较简便。当然，若如上述步骤S140中所示，转移基板40上带有粘附层，则此时剥离转移基板40可通过对转移基板40与LED芯片20之间的粘附层进行解胶实现。
由以上描述可知，本申请实施例提供的LED芯片的转移方法，通过借助具有特殊堆叠胶层结构的微型元件结构，可在从该微型元件结构上转移LED芯片20至转移基板40时，通过较低能量的激光就可实现对与芯片连接的光解胶层31’的解胶，且热解胶层32’还能阻挡激光照射到LED芯片20上，从而大大减少采用激光转移LED芯片20的过程中对芯片的损伤，显著提高芯片的转移良率。此外，当转移基板40上的LED芯片20再次转移至显示背板50时，热解胶层32’还可在热熔化、冷却后较好地填充芯片的引出电极和显示背板上的焊盘组之间的空隙，进一步提高LED芯片20和显示背板50之间的键合力。因此，本申请实施例提供的上述LED芯片的转移方法简单，操作便捷，对LED芯片的转移良率高，且LED芯片与显示背板之间的结合力强。
基于上述任意实施例提供的LED芯片的转移方法，参考图18，本申请实施例还提供一种显示装置，该显示装置具体包括显示背板50和多个LED芯片20，其中LED芯片20采用上述任意实施例提供的转移方法转移至显示背板50上。该显示装置可以为LED显示面板，以及使用该LED显示面板的电视、电脑和工业计算机等设备。
应当理解的是，本申请的应用不限于上述的举例，对本领域普通技术人员来说，可以根据上述说明加以改进或变换，所有这些改进和变换都应属于本申请所附权利要求的保护范围。

Claims (17)

  1. 一种微型元件结构，其特征在于，包括：
    衬底，所述衬底具有第一表面；
    间隔设置在所述第一表面上的多个堆叠胶层结构；
    对应设置在多个所述堆叠胶层结构上的多个LED芯片，所述LED芯片朝向所述堆叠胶层结构的表面具有两个引出电极；
    其中，所述堆叠胶层结构包括层叠设置的光解胶层和热解胶层，且所述光解胶层与所述第一表面接触，所述热解胶层位于两个所述引出电极之间，且所述热解胶层的厚度大于所述引出电极的高度。
  2. 根据权利要求1所述的微型元件结构，其特征在于，所述热解胶层的热熔温度低于所述光解胶层的热熔温度，所述热解胶层与所述光解胶层的热熔温度之差大于20℃。
  3. 根据权利要求1所述的微型元件结构，其特征在于，所述热解胶层的厚度大于所述光解胶层的厚度。
  4. 根据权利要求3所述的微型元件结构，其特征在于，所述光解胶层的厚度在2μm-3μm的范围内。
  5. 根据权利要求3所述的微型元件结构，其特征在于，所述热解胶层的厚度在4μm-6μm的范围内。
  6. 根据权利要求1-5中任一项所述的微型元件结构，其特征在于，所述光解胶层的宽度大于或等于所述热解胶层的宽度。
  7. 根据权利要求6所述的微型元件结构，其特征在于，所述光解胶层的宽度在4μm-9μm的范围内。
  8. 根据权利要求6所述的微型元件结构，其特征在于，所述热解胶层的宽度在2μm-6μm的范围内。
  9. 一种微型元件结构的制备方法，其特征在于，包括：
    在衬底的第一表面上依次制备层叠设置的光解胶材和热解胶材；
    将生长有多个LED芯片的生长基板与所述衬底进行热键合，使所述LED芯片嵌入所述热解胶材中，且所述LED芯片的两个引出电极朝向所述光解胶材；
    剥离所述生长基板；
    去除相邻两个所述LED芯片之间的热解胶材，对剩下的热解胶材及所述光解胶材进行刻蚀，以在所述衬底和每个所述LED芯片之间形成堆叠胶层结构；其中，所述堆叠胶层结构包括光解胶层和热解胶层，且所述光解胶层在所述第一表面上间隔分布；所述热解胶层位于所述LED芯片的两个引出电极之间，且所述热解胶层的厚度大于所述引出电极的高度。
  10. 根据权利要求9所述的制备方法，其特征在于，所述热解胶材的热熔温度低于所述光解胶材的热熔温度，所述热解胶材与所述光解胶材的热熔温度之差大于20℃。
  11. 根据权利要求9或10所述的制备方法，其特征在于，所述层叠设置的光解胶材和热解胶材中，所述热解胶材的厚度应大于或等于所述LED芯片的高度。
  12. 根据权利要求9或10所述的制备方法，其特征在于，所述层叠设置的光解胶材和热解胶材中，所述光解胶材的厚度在2μm-3μm的范围。
  13. 根据权利要求9所述的制备方法，其特征在于，所述去除相邻两个所述LED芯片之间的热解胶材的方式为湿法刻蚀；所述湿法刻蚀采用丙酮或N-甲基吡咯烷酮中的至少一种作为刻蚀液。
  14. 根据权利要求9所述的制备方法，其特征在于，所述去除相邻两个所述LED芯片之间的热解胶材的方式为干法刻蚀；所述干法刻蚀采用的刻蚀气体包括氧气。
  15. 根据权利要求11所述的制备方法，其特征在于，对剩下的热解胶材及所述光解胶材进行的所述刻蚀为干法刻蚀，所述干法刻蚀包括先采用氧气刻蚀10-20min，再采用含氟气体刻蚀5-8min。
  16. 一种LED芯片的转移方法，其特征在于，包括：
    提供根据权利要求1-8中任一项所述的微型元件结构，将转移基板贴合至所述微型元件结构设置有所述LED芯片的一侧，对所述光解胶层进行激光照射，以使所述LED芯片和所述热解胶层转移到所述转移基板；
    将所述转移基板上的所述LED芯片转移至显示背板。
  17. 根据权利要求16所述的LED芯片的转移方法，其特征在于，所述将所述转移基板上的所述LED芯片转移至显示背板，包括：
    将所述转移基板带有所述LED芯片的一侧与所述显示背板设有多个焊盘组的一侧对向放置，经热键合，使所述引出电极与所述焊盘组对应电连接，冷却后，所述引出电极与所述焊盘组之间的空间填充有所述热解胶层；
    剥离所述转移基板。
PCT/CN2021/112585 2021-08-13 2021-08-13 微型元件结构及其制备方法、led芯片的转移方法 WO2023015569A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110546751A (zh) * 2018-06-11 2019-12-06 厦门三安光电有限公司 发光组件
CN110828364A (zh) * 2019-11-20 2020-02-21 广东省半导体产业技术研究院 巨量转移方法、显示装置的制作方法和显示装置
CN111489991A (zh) * 2020-04-22 2020-08-04 京东方科技集团股份有限公司 显示面板及制作方法
CN112289908A (zh) * 2020-09-11 2021-01-29 罗化芯显示科技开发(江苏)有限公司 一种mini-LED芯片巨量转移的方法
CN112582520A (zh) * 2020-12-29 2021-03-30 苏州芯聚半导体有限公司 微发光二极管转移方法及显示面板
CN112968108A (zh) * 2020-08-24 2021-06-15 重庆康佳光电技术研究院有限公司 一种发光结构的转移方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110546751A (zh) * 2018-06-11 2019-12-06 厦门三安光电有限公司 发光组件
CN110828364A (zh) * 2019-11-20 2020-02-21 广东省半导体产业技术研究院 巨量转移方法、显示装置的制作方法和显示装置
CN111489991A (zh) * 2020-04-22 2020-08-04 京东方科技集团股份有限公司 显示面板及制作方法
CN112968108A (zh) * 2020-08-24 2021-06-15 重庆康佳光电技术研究院有限公司 一种发光结构的转移方法
CN112289908A (zh) * 2020-09-11 2021-01-29 罗化芯显示科技开发(江苏)有限公司 一种mini-LED芯片巨量转移的方法
CN112582520A (zh) * 2020-12-29 2021-03-30 苏州芯聚半导体有限公司 微发光二极管转移方法及显示面板

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