transfer substrate

Abstract

The embodiment of the present disclosure provides a transfer substrate for picking up electronic elements, comprising: a substrate body, a plurality of protrusions are arranged on a first surface of the substrate body along a first direction, the first direction being perpendicular to a plane on which the substrate body is located; and a first self-cleaning layer for cleaning the transfer substrate, the first self-cleaning layer being located on the same side of the substrate body as the protrusions, and the first self-cleaning layer and the protrusions not overlapping in the first direction. By arranging the first self-cleaning layer on the first surface of the substrate body, the first self-cleaning layer is less likely to adsorb particles than a high polymer material, and even if particles fall on the first self-cleaning layer, they are relatively easy to remove. In this way, during the transfer process of the transfer substrate for Micro LED and other electronic elements, the influence of particles on the transfer process of Micro LED and other electronic elements can be reduced, thereby reducing the influence of particles on the yield of Micro LED and reducing the cleaning frequency of the transfer substrate.

Description

[Technical Field]

[0001] This disclosure relates to the field of display technology, and more particularly to transfer substrates. [Background Technology]

[0002] Micro LED (Micro Light-Emitting Diode) is a display technology that miniaturizes and matrixes the structure of a traditional light-emitting diode (LED) and uses integrated circuit technology to fabricate a substrate for transfer. By transferring the Micro LED onto the substrate using mass transfer technology, the addressing control and individual driving of each pixel can be achieved.

[0003] MicroLED displays outperform LCD and OLED displays in terms of brightness, lifespan, contrast ratio, response time, energy consumption, viewing angle, and resolution. Combined with their self-emissive nature, simple structure, small size, and energy efficiency, they are considered the next generation of display technology and have garnered widespread attention.

[0004] In Micro-LED display technology, improving the yield of Micro-LEDs during the mass transfer process has always been a major challenge. [Summary of the Invention]

[0005] In view of the above, the first aspect of this disclosure provides a transfer substrate for picking up electronic components. The transfer substrate includes: a substrate body, a first surface of the substrate body having a plurality of protrusions along a first direction, the first direction being perpendicular to the plane in which the substrate body is located; and a first self-cleaning layer for cleaning the transfer substrate, the first self-cleaning layer and the protrusions being located on the same side of the substrate body, and the first self-cleaning layer and the protrusions not overlapping in the first direction.

[0006] This disclosure provides a first self-cleaning layer on the first surface of the substrate body. This first self-cleaning layer has self-cleaning capabilities, removing particles and other substances that fall into it. In this way, during the transfer of electronic components such as Micro LEDs by the transfer substrate, the negative impact of particles on the transfer process can be reduced, minimizing interference with Micro LED yield and indirectly reducing the number of times the transfer substrate needs to be cleaned, thus extending the lifespan of the transfer substrate. [Attached Image Description]

[0007] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a cross-sectional schematic diagram of a quantum dot display panel employing photoluminescence technology in related technologies;

[0009] Figure 2 A top view of a transfer substrate provided in one embodiment of this disclosure;

[0010] Figure 3 for Figure 2 A cross-sectional view of the provided transfer substrate along the A-A' direction;

[0011] Figure 4 Provided for another embodiment of this disclosure Figure 2 A cross-sectional view of the transfer substrate along the A-A' direction;

[0012] Figure 5 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure;

[0013] Figure 6 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure;

[0014] Figure 7 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure;

[0015] Figure 8 A top view of a transfer substrate provided in another embodiment of this disclosure;

[0016] Figure 9 for Figure 8 A cross-sectional view of the provided transfer substrate along the B-B' direction;

[0017] Figure 10 This is a cross-sectional view of the transfer substrate in another embodiment of this disclosure.

Detailed Implementation Methods

[0018] To better understand the technical solutions of this disclosure, the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0019] It should be understood that the described embodiments are merely some, not all, of the embodiments disclosed herein. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0020] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The singular forms “a,” “the,” and “the” as used in the embodiments of this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0022] See Figure 1 This is an example diagram of a transfer substrate 100' provided in the related art.

[0023] In related technologies, the transfer substrate 100' is used to pick up a light-emitting diode (LED) from the growth substrate. It is understood that the LED can be any type of LED in the prior art. Further, after picking up the LED, it is transferred to a target substrate. The target substrate may include a driving substrate. The driving substrate includes a thin-film transistor for driving the LED to emit light and bonding pads for bonding with the LED. These related technologies are all prior art and will not be described in detail here.

[0024] See also Figure 1 The transfer substrate 100' includes a substrate body 102' and a protrusion 104 located on one side of the transfer substrate 102', which is used to pick up light-emitting diodes.

[0025] The applicant discovered that in related technologies, the substrate body 102' is generally made of polymer materials such as polydimethylsiloxane, which readily adsorbs contaminants such as particles. These contaminants can negatively impact the yield of the transferred light-emitting diodes. To address this technical problem, existing technologies typically increase the number of cleaning cycles for the transfer substrate, but this shortens the substrate's lifespan.

[0026] To address the aforementioned technical problems, this disclosure provides a novel transfer substrate, as detailed below. Figure 2 -Appendix Figure 3 The transfer substrate 100 provided in this disclosure will be explained and described in detail.

[0027] See Figure 2 Specifically, this is a top view of a transfer substrate provided in one embodiment of this disclosure. Figure 3 for Figure 2A cross-sectional view of the provided transfer substrate 100 along the A-A' direction.

[0028] The transfer substrate 100 includes a substrate body 102. Along a first direction, a plurality of protrusions 104 are provided on a first surface of the substrate body 102, the first direction being perpendicular to the plane in which the substrate body 102 is located. It should be noted that the number of protrusions on the substrate body 102 in the accompanying drawings is merely exemplary and does not constitute a substantial limitation on the present disclosure. Those skilled in the art can flexibly set the number of protrusions as needed.

[0029] like Figure 3 As shown, along the first direction, a plurality of protrusions 104 are provided on the first surface 108 of the substrate body 102, which are used to pick up electronic components. It can be understood that the first surface 108 of the substrate body 102 is specifically the side surface of the substrate body 102 on which the protrusions 104 are provided. Further, the electronic component may include a Micro LED, or it may include a Mini Light-Emitting Diode (Mini LED). This disclosure does not specifically limit the type of LED.

[0030] The transfer substrate 100 also includes a first self-cleaning layer 106, which is used to clean the transfer substrate 100. The first self-cleaning layer 106 and the protrusion 104 are located on the same side of the substrate body 102, and the first self-cleaning layer 106 and the protrusion 104 do not overlap along the first direction.

[0031] The inventors discovered that by providing a first self-cleaning layer on the first surface of the substrate body, this disclosure enables the removal of particles and other substances that fall into the first self-cleaning layer. In this way, during the transfer of electronic components such as Micro LEDs by the transfer substrate, the negative impact of particles on the transfer process can be reduced, thus decreasing the interference of particles on the yield of Micro LEDs and indirectly reducing the number of times the transfer substrate needs to be cleaned.

[0032] See Figure 4 , Figure 4 Provided for another embodiment of this disclosure Figure 2 A cross-sectional view of the transfer substrate 100 along the A-A' direction.

[0033] and Figure 3 The difference between the embodiments shown is that, Figure 4 In the embodiment shown, along the second direction, the first self-cleaning layer 106 partially covers the side of the protrusion 104. It can be seen that the first direction intersects with the second direction. Optionally, the second direction is parallel to the plane where the substrate body 102 is located.

[0034] Furthermore, in this disclosure, the thickness of the first self-cleaning layer on the side of the protrusion 104 can be the same as or different from the thickness of the first self-cleaning layer on the first surface 108. It is understood that since the protrusion 104 is directly used to pick up electronic components such as Micro LEDs, partially covering the side of the protrusion 104 with the first cleaning layer 106 can better prevent excessive particles from adsorbing near the protrusion 104, thereby affecting the yield of Micro LEDs.

[0035] In one embodiment of this disclosure, the thickness of the first self-cleaning layer on the side of the protrusion 104 is less than the thickness of the first self-cleaning layer on the first surface 108. It is understood that contaminants such as particles on the transfer substrate generally fall onto the first surface 108 more due to gravity. Therefore, setting the thickness of the first self-cleaning layer on the first surface 108 to be greater than the thickness of the first self-cleaning layer on the side of the protrusion 104 can better clean contaminants such as particles.

[0036] In one embodiment of this disclosure, at least a portion of the side of the first self-cleaning layer 106 away from the substrate body 102 has a contact angle with water greater than 150°.

[0037] As shown above, in related technologies, transfer substrates are generally made of polymer materials, which easily adsorb particulate matter and other contaminants. Generally, the larger the contact angle between a substance and water, the stronger its hydrophobicity. In this disclosure, the first self-cleaning layer has a contact angle with water of at least 150 degrees, exhibiting strong hydrophobicity. When water droplets form on the surface of the first self-cleaning layer 106, they roll on the surface, carrying away particulate matter and other harmful substances, thus preventing the possibility of particulate interference during Micro LED transfer. Furthermore, when cleaning the transfer substrate, the first self-cleaning layer also provides some protection for the substrate body 102 and the protrusions 104.

[0038] In another embodiment of this disclosure, the first self-cleaning layer 106 may include a photocatalytic semiconductor coating. The photocatalytic semiconductor coating generally produces self-cleaning, anti-fogging, and decomposition of harmful gases in the environment based on effects such as oxidative decomposition. In one embodiment of this disclosure, in a first state, the contact angle between the first self-cleaning layer 106 and water is at least 70°, and in a second state, the contact angle between the first self-cleaning layer and water is less than 5°; wherein the ultraviolet light intensities of the first state and the second state are different.

[0039] The cleaning principle of the first self-cleaning layer 106, which is TiO2, will be explained and illustrated below.

[0040] Depending on the processing method and the environment, TiO2 can exhibit three effects: semiconductor effect, superamphilic effect, and oxidative decomposition effect. The latter two effects are primarily responsible for self-cleaning, anti-fogging, and decomposition of harmful gases in the environment. This disclosure focuses mainly on the self-cleaning effect of TiO2.

[0041] TiO2 is an N-type semiconductor that can absorb short-wavelength light (especially ultraviolet light) with a band gap greater than its width, causing its entrained electrons to jump to the conduction band and simultaneously forming holes. Specifically, TiO2 has continuous energy levels. The diameter of TiO2 nanoparticles is generally between 1-100 nm, so the Fermi levels of their electrons are independently distributed. There is an empty energy region in its molecular and atomic orbitals, which lies between the conduction band and the valence band and is called the band gap, with a width of 3.2 eV. When ultraviolet light with a wavelength below 387.5 nm irradiates nano-TiO2, the electrons in its internal bands absorb the energy of the photons and jump to the conduction band, thereby generating electron-hole pairs, i.e., generating photogenerated charge carriers. These carriers then rapidly transfer to the surface and activate the adsorbed oxygen and water molecules, thereby generating highly active free radicals and superoxide ion free radicals. When pollutants and bacteria are adsorbed onto the surface, the electrons in the generated electron-hole pairs can be used to reduce oxygen in the environment, while the holes play a role in adsorbing and decomposing these adsorbed substances, breaking them down into small molecules of water and carbon dioxide.

[0042] The self-cleaning effect of TiO2 is achieved not only through oxidative decomposition but also through its superamphilic effect under photocatalysis. The superamphilic effect refers to TiO2 exhibiting both hydrophilic and hydrophobic properties under different UV light intensities. Specifically, in darkness (i.e., without UV light), at least a portion of the TiO2 coating surface has a contact angle of at least 70 degrees with water droplets, exhibiting hydrophobicity. However, under UV light, the contact angle between at least a portion of the TiO2 coating surface and water droplets changes, becoming less than or equal to 5°, typically between 0-2°, making it superhydrophilic. Even after UV light exposure ceases, the surface hydrophilicity can be maintained for several hours to a week before slowly reverting to a hydrophobic state. When the TiO2 surface is in a superhydrophilic state, it exhibits characteristics such as easy cleaning and quick drying. In other words, this disclosure allows for easier cleaning and quicker drying of the first self-cleaning layer 106 when it is in a superhydrophilic state.

[0043] Furthermore, TiO2 generates holes under photocatalysis, which in turn generate hydroxyl radicals. These hydroxyl radicals can degrade most organic and inorganic pollutants, ultimately reducing them to easily cleanable substances such as carbon dioxide and water. Many particulate pollutants have oxidation potentials that are more negative than the valence band potential of TiO2, allowing them to be directly oxidized by these holes. Therefore, using a photocatalytic semiconductor coating such as TiO2 as the first self-cleaning layer effectively prevents particulate interference with micro-LED yield.

[0044] It should be noted that the photocatalytic semiconductor coating is not limited to TiO2 material. Those skilled in the art can select a photocatalytic semiconductor coating with the same or similar properties as TiO2 material as the self-cleaning layer in this disclosure, as needed. For example, at least one of ZnO, TiO2, WO3, SnO2, Fe2O3, ZnS, and SrTiO3 can also be selected as the photocatalytic semiconductor coating.

[0045] See Figure 5 , Figure 5 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure. Figure 5 In the embodiment shown, the substrate body 102 further includes at least one second surface 112 and / or a third surface 114. It can be seen that the second surface 112 intersects with the first surface 108, and the third surface 114 is disposed opposite to the first surface 108.

[0046] Furthermore, the transfer substrate provided in this disclosure may further include a second self-cleaning layer 110. Optionally, the second self-cleaning layer 110 may at least partially cover the second surface 112. It is understood that in related technologies, some particles may adhere to the sidewalls (i.e., the second surface 112) of the substrate body 102 and may fall into the first surface 108 during the micro-LED transfer process, negatively impacting yield. The second self-cleaning layer 110, by at least partially covering the second surface 112, reduces the likelihood of particles on the second surface 112 falling into the first surface 108 due to its self-cleaning function, thereby improving the yield of the micro-LED.

[0047] It should be noted that the first self-cleaning layer 106 and the second self-cleaning layer 110 of this disclosure can be formed by various methods. In one example of this disclosure, the first self-cleaning layer 106 and the second self-cleaning layer 110 can be formed by physical vapor deposition (PVD). Specifically, PVD can include ion beam assisted deposition, radio frequency sputtering, magnetron sputtering, activated reactive evaporation, DC sputtering, and filtered arc deposition, etc. Magnetron sputtering is commonly used in experiments. Its basic principle is to ionize some inert gas in a vacuum environment to generate plasma. Under a specific bias voltage, the plasma gas bombards the target material, sputtering out target metal ions, which are then deposited on the target substrate to form a thin film. In one example of this disclosure, the first self-cleaning layer 106 and the second self-cleaning layer 110 can also be prepared by chemical vapor deposition (CVD). CVD can include metal-organic chemical vapor deposition (MOCVD), plasma-enhanced chemical vapor deposition (PECVD), and laser chemical vapor deposition (LACVD). Metal-organic chemical vapor deposition is the lowest-cost and easiest-to-control thin film technology. This disclosure preferably uses this scheme to prepare the first self-cleaning layer 106 and the second self-cleaning layer 110.

[0048] See Figure 6 , Figure 6 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure. Figure 5 Unlike the illustrated embodiment, the second self-cleaning layer 110 at least partially covers the third surface 114. It is understood that in related technologies, some microparticles adhere to one side (i.e., the third surface 114) of the first surface 108 of the transfer body, and may fall into the first surface 108 during the micro-LED transfer process, negatively impacting yield. In this disclosure, the second self-cleaning layer 110 at least partially covers the third surface 114 of the basic body, reducing the possibility of microparticles on the third surface 114 falling into the first surface 108, thereby preventing microparticles from affecting the micro-LED yield.

[0049] See Figure 7 , Figure 7 A schematic diagram of the structure of a transfer substrate is provided for another embodiment of this disclosure. Figure 5 and Figure 6 Unlike the embodiment shown, the second self-cleaning layer 110 can at least partially cover the second surface 112 and the third surface 114 respectively, which better avoids particles from affecting the yield of micro-LEDs.

[0050] In one embodiment of this disclosure, the thickness of the second self-cleaning layer 110 is greater than the thickness of the first self-cleaning layer 106. The applicant also found that, to avoid the first self-cleaning layer 106 being too thick, resulting in too few protrusions exposed outside the first self-cleaning layer and affecting the pickup effect of the protrusions 104 on the micro-LED, the thickness of the first self-cleaning layer 106 needs to be limited to a certain extent. However, since the second surface 112 and the third surface 114 do not have protrusions 106, the thickness of the second self-cleaning layer 110 can be set to be slightly thicker than the first self-cleaning layer 106, in order to better reduce the probability of particles falling into the second surface 112 and the third surface 114, thus affecting the yield of the micro-LED.

[0051] In one embodiment of this disclosure, the ratio of the height of the protrusion 104 to the thickness of the first self-cleaning layer 106 ranges from 2 to 25, including the endpoint values. It is understood that the height of the protrusion 104 refers to the distance between the end of the protrusion 104 furthest from the substrate body 102 and the first surface 108 of the substrate body. It is understood that to ensure the protrusion 104 can pick up electronic components such as micro-LEDs, the height of the protrusion 104 must be greater than the thickness of the first self-cleaning layer 106. That is, if the thickness of the first self-cleaning layer 106 is too thick, resulting in too few protrusions exposed outside the first self-cleaning layer, it may affect the protrusion 104's ability to pick up micro-LEDs. However, if the thickness of the first self-cleaning layer 106 is too thin, it may affect its self-cleaning effect. Through significant cost expenditure, the inventors discovered that when the ratio of the height of the protrusion 104 to the thickness of the first self-cleaning layer 106 is in the range of 2 to 25, both the self-cleaning effect and the ability of the protrusion 104 to effectively pick up electronic components such as micro-LEDs can be guaranteed. Optionally, in a specific example of this disclosure, the thickness of the first self-cleaning layer is greater than or equal to 0.5 μm, and the height of the protrusion is greater than or equal to 10 μm.

[0052] In one embodiment of this disclosure, the protrusion is integrally formed with the substrate body. This arrangement simplifies the process of fabricating the transfer substrate and reduces manufacturing costs.

[0053] See Figure 8 and Figure 9 , Figure 8 A top view of a transfer substrate provided in another embodiment of this disclosure. Figure 9 for Figure 8 A cross-sectional view of the provided transfer substrate along the B-B' direction.

[0054] Figure 8 and Figure 9As shown, the first surface 108 of the substrate body 102 includes a central region 118 and an edge region 116, with the edge region 116 surrounding the central region 118. Since the edge region 116 is closer to the outer side than the central region 118, the protrusions 104 in the edge region 116 are more likely to adsorb particles during the transfer of electronic components such as micro-LEDs. Based on this, this disclosure allows the thickness of the first self-cleaning layer 106 in the central region 118 to be less than its thickness in the edge region 116. The thicker the first self-cleaning layer 106 in the edge region 116, the stronger the self-cleaning ability, which better reduces the possibility of the protrusions in the edge region 116 adsorbing contaminants such as particles, thus improving the yield of micro-LEDs. The central region 118, compared to the edge region 116, is less susceptible to contamination, and a thinner first self-cleaning layer can be provided in the central region 118. See also... Figure 10 ,exist Figure 10 In the embodiment, the middle region 118 may not have a first self-cleaning layer, which can reduce process costs while ensuring the cleanliness of the substrate body 102.

[0055] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A transfer substrate for picking up electronic components, characterized in that, include: The substrate body has a plurality of protrusions on its first surface along the second direction, the second direction intersects with the first direction, and the first direction is perpendicular to the plane in which the substrate body is located; A first self-cleaning layer is used to clean the transfer substrate. The first self-cleaning layer and the protrusion are located on the same side of the substrate body. The orthographic projection of the first self-cleaning layer on the first surface of the substrate body and the orthographic projection of the protrusion on the first surface of the substrate body do not overlap. The first self-cleaning layer includes a photocatalytic semiconductor coating; in, The first surface includes a central region and an edge region, the edge region being disposed around the central region; the thickness of the first self-cleaning layer in the central region is less than the thickness of the first self-cleaning layer in the edge region; or, The first surface includes a central region and an edge region, the edge region being disposed around the central region; the first self-cleaning layer is disposed only in the edge region; or, The protrusion includes a side extending along the first direction, and the first self-cleaning layer partially covers the side of the protrusion.

2. The transfer substrate according to claim 1, characterized in that, At least a portion of the first self-cleaning layer on the side away from the substrate body has a contact angle with water greater than 150°.

3. The transfer substrate according to claim 1, characterized in that, In the first state, the contact angle between the first self-cleaning layer and water is at least 70°; Under the second state condition, the contact angle between the first self-cleaning layer and water is less than 5°; The ultraviolet light intensities are different in the first state and the second state.

4. The transfer substrate according to claim 1, characterized in that, The photocatalytic semiconductor coating includes at least one of ZnO, TiO2, WO3, SnO2, Fe2O3, ZnS, and SrTiO3.

5. The transfer substrate according to claim 1, characterized in that, The substrate body further includes at least one second surface and / or a third surface, wherein the second surface intersects with the first surface and the third surface is disposed opposite to the first surface; The transfer substrate further includes a second self-cleaning layer, the second self-cleaning layer at least partially covering the second surface, and / or, The second self-cleaning layer at least partially covers the third surface.

6. The transfer substrate according to claim 5, characterized in that, The thickness of the second self-cleaning layer is greater than the thickness of the first self-cleaning layer.

7. The transfer substrate according to claim 1, characterized in that, In the first direction, the ratio of the height of the protrusion to the thickness of the first self-cleaning layer ranges from 2 to 25, including the endpoint values.

8. The transfer substrate according to claim 7, characterized in that, The thickness of the first self-cleaning layer is greater than or equal to 0.5 μm; The height of the protrusion is greater than or equal to 10 μm.

9. The transfer substrate according to claim 1, characterized in that, The protrusion is integrally formed with the substrate body.

10. The transfer substrate according to claim 1, characterized in that, The electronic components include mini-LEDs or micro-LEDs.

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