TWI802062B - LED chip assembly, display panel and manufacturing method - Google Patents

Abstract

The invention relates to an LED chip component, a display panel and a preparation method. The LED chip assembly includes a substrate, a plurality of LED chips on the substrate, and at least two marking bases, the marking bases are formed on the same growth substrate as the LED chips, and can be transferred to the transient substrate together with the LED chips On the other hand, it is used for positioning during the transfer process of the LED chip. The LED chip assembly provides a solution for setting alignment marks on the transient substrate. In this solution, the transfer process of the LED chip and the marking base can be realized together to avoid After setting the marking base on the substrate other than the growth substrate, it is necessary to transfer the marking base and the LED chip to the transient substrate separately, which improves the setting efficiency of the alignment mark on the transient substrate, and is conducive to the improvement of mass transfer efficiency.

Description

LED chip assembly, display panel and manufacturing method

The present invention claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on October 28, 2020, with the application number 202011170615.0 and the title of the invention "LED chip assembly, display panel and manufacturing method", the entire contents of which are incorporated by reference In the present invention.

The invention relates to the technical field of LEDs, in particular to an LED chip assembly, a display panel and a preparation method.

The radiation theory and structure of light-emitting diodes (Light-Emitting Diode; LED) are different from traditional light sources, such as fluorescent lamps or incandescent lamps. LEDs have the advantages of low power consumption, long life and fast response time. In addition, LEDs are compact, shockproof, and environmentally friendly, so LEDs are widely adopted in the market. For example, LEDs can be used in display devices, indoor or outdoor lighting, data storage devices, communication devices, medical devices, and the like.

LED can be used as the backlight of the display device, or as the pixel unit of the display device after being reduced in size (micron level), and the mass transfer technology has become the key to making the small-sized LED the pixel unit. In the mass transfer of LED wafers, especially in the case of using excimer laser mass transfer, it is necessary to set alignment marks (Mark) on the transient substrate (Donor) and the drive substrate, and use the alignment marks to realize temporary The LED chip on the state substrate is aligned with the chip setting area on the drive substrate, so that multiple LED chips on the transient substrate are transferred to the drive substrate together. However, there is currently no reliable way of setting alignment marks on transient substrates.

Therefore, how to set the alignment mark on the transient substrate is an urgent problem to be solved.

In view of the deficiencies of the above-mentioned related technologies, the embodiments of the present invention provide an LED chip assembly, a display panel and a manufacturing method, which can solve the problem of setting alignment marks on the transient substrate.

A LED chip assembly, comprising: Substrate; a plurality of LED chips on the surface of the substrate; and At least two marked base pieces; Wherein, the marking base part and the LED chip are on the same surface of the substrate, and the marking base part and the LED chip are formed on the same growth substrate; the marking base part is used for positioning in the process of transferring multiple LED chips.

The above-mentioned LED chip assembly includes a substrate, a plurality of LED chips on the substrate, and at least two marking bases, which are formed on the same growth substrate as the LED chips, and can be transferred to a transient state together with the LED chips. On the substrate, it is used for positioning during the transfer process of the LED chip. The LED chip assembly provides a solution for setting alignment marks on the transient substrate. In this solution, the transfer process of the LED chip and the marking base can be realized together. It avoids the problem of transferring the marking base and the LED chip to the transient substrate separately after setting the marking base on the substrate other than the growth substrate, and improves the setting efficiency of the alignment mark on the transient substrate, which is conducive to improving the huge amount of transfer efficiency.

In at least one exemplary embodiment, at least part of the material of the marking base is the same as at least part of the material of the LED chip.

In the above-mentioned LED chip assembly, at least part of the material of the marking base part is the same as at least part of the material of the LED chip. Therefore, part of the forming materials of the marking base part and the LED chip can be shared, which simplifies the material preparation process before forming the marking base part and the LED chip. , improving production efficiency.

In at least one exemplary embodiment, the marking base member includes a plurality of layer structures, wherein n consecutive layer structures in the multiple layer structures constitute the first partial layer, and the continuous n layer structures in the LED wafer constitute the second partial layer, and n is greater than or equal to 2. The material for forming the first sub-layer is the same as the material for forming the second sub-layer, and the relative position of the layer structure of the same material in the first sub-layer is the same as that in the second sub-layer.

The marking base part in the above-mentioned LED chip assembly is also a composite layer structure, and wherein the forming material of the first partial layer structure is the same as that of the second partial layer structure in the LED chip, and the layer structure of the same material is in the first partial layer structure The relative position is the same as in the second partial layer structure. Therefore, the process of forming the first sub-layer structure of the marking base part and the process of forming the second part-layer structure of the LED chip can be carried out simultaneously using the same material, which helps to reduce the time spent forming the marking base part and reduce the cost of forming the mark. The additional burden brought by basic parts improves production efficiency and production benefits.

In at least one exemplary embodiment, the marking base comprises a dead pixel LED wafer grown on a growth substrate.

The marking base part in the above-mentioned LED chip assembly directly includes the LED chips with bad spots on the growth substrate. By growing the LED chips on the growth substrate, and then determining the bad spot LED chips in these LED chips as the marking base parts, not only eliminates the The process of specially preparing materials for the formation of marking base parts also avoids the process of specially forming marking base parts, which reduces the time-consuming and cost of forming marking bases; moreover, because LED chips with dead pixels are used to form marking base parts, it is effectively used The original useless LED chips with dead pixels are eliminated, the use value of the LED chips with dead pixels is given, and the utilization rate of the LED chips grown on the growth substrate is improved.

In at least one exemplary embodiment, the substrate includes a growth substrate or a transient substrate.

Based on the same inventive concept, an embodiment of the present invention also provides a method for manufacturing an LED chip assembly, including: Preparing LED wafers on growth substrates and forming marking bases; and The LED chip and the marking base are transferred from the growth substrate to the transient substrate to obtain an LED chip assembly; the marking base is used for positioning during the process of transferring the LED chip from the transient substrate to the driving substrate.

In the manufacturing method of the above-mentioned LED chip assembly, the LED chip is firstly prepared on the growth substrate and the marking base is formed, and then the LED chip and the marking base are transferred from the growth substrate to the transient substrate. Since the marking base can be formed on the growth substrate and transferred to the transient substrate together with the LED chip, it is used for positioning during the process of transferring the LED chip from the transient substrate to the driving substrate. The preparation method of the LED chip assembly provides a scheme for setting alignment marks on the transient substrate, in which the transfer process of the LED wafer and the marking base can be realized together, avoiding setting the marking base on the substrate other than the growth substrate After the parts are completed, it is necessary to transfer the marking base parts and LED chips to the transient substrate separately, which improves the setting efficiency of the alignment mark on the transient substrate and is conducive to improving the mass transfer efficiency.

In at least one exemplary embodiment, forming the marking base is achieved by one of the following methods: Way 1: using materials that form at least part of the layer structure of the LED chip to form a marking base in the free area of the growth substrate; wherein, the free area is the area outside the wafer growth area on the growth substrate; Method 2: After the LED chip is prepared, the LED chip is inspected to identify the defective LED chip, and the defective LED chip is used as a marking base.

In the above-mentioned LED chip preparation method, if the first method is used to form the marking base part, the material for preparing the partial layer structure of the LED wafer can be used to form the marking base part in the free area of the growth substrate, so the material forming the marking base part and the part of the LED chip The forming materials can be shared, which simplifies the material preparation process before forming the marking base part and the LED chip, and improves the production efficiency.

In the above-mentioned LED chip preparation method, if the second method is used to form the marking base, LED wafers can be grown on the growth substrate, and then the LED chips with dead spots in these LED chips can be determined as the marking base, which not only eliminates the need for The process of forming a special material preparation for the marking base part also avoids the process of specially forming the marking base part, which reduces the time-consuming and cost of forming the marking base; moreover, because the bad point LED chip is used to form the marking base part, it is effectively used The originally useless dead pixel LED chip gives the dead pixel LED chip a use value and improves the utilization rate of the LED chip grown on the growth substrate.

Based on the same inventive concept, an embodiment of the present invention also provides a display panel, which includes: drive substrate; A plurality of LED chips arranged in the chip setting area of the driving substrate and electrically connected to the driving circuit in the driving substrate; and At least two marking bases, the marking base and parts of the multiple LED chips are grown on the same growth substrate, and transferred to the driving substrate through the same transient substrate; the marking base is used to transfer from the transient substrate to the driving substrate It plays a positioning role in the process of transferring LED wafers.

The above display panel includes a driving substrate and at least two marking bases, wherein the marking base and part of the LED chips on the driving substrate are grown on the same growth substrate and can be transferred from the same transient substrate. In this way, a solution for setting alignment marks on the transient substrate is provided. In this solution, the transfer process of the LED wafer and the marking base can be realized together, avoiding the need to set the marking base on a substrate other than the growth substrate. , the need to transfer the marking base part and the LED chip to the transient substrate separately, which improves the setting efficiency of the alignment mark on the transient substrate, and is conducive to improving the mass transfer efficiency.

In at least one exemplary embodiment, the marking base comprises a dead pixel LED wafer grown on a growth substrate.

In the above-mentioned display panel, the marking base part directly includes the dead pixel LED chip on the growth substrate. By growing the LED chip on the growth substrate, and then determining the dead pixel LED chip in these LED chips as the marking base part, it not only eliminates the need for The process of forming a special material preparation for the marking base part also avoids the process of specially forming the marking base part, which reduces the time-consuming and cost of forming the marking base; moreover, because the bad point LED chip is used to form the marking base part, it is effectively used The originally useless dead pixel LED chip gives the dead pixel LED chip a use value and improves the utilization rate of the LED chip grown on the growth substrate.

Based on the same inventive concept, an embodiment of the present invention also provides a method for manufacturing a display panel, including: A driving substrate is provided; wherein, at least two second alignment marks are formed on the driving substrate; According to the positional relationship of the second alignment marks on the drive substrate, the LED chip assembly of any one of the foregoing is formed; Realize the alignment of the driving substrate and the LED chip assembly through the second alignment mark and the marking base; After the position alignment is completed, the LED chip is bonded to the driving substrate and peeled off from the substrate of the LED chip assembly.

In the above method of manufacturing a display panel, a driving substrate is provided first, and then a corresponding LED chip assembly is formed according to the positional relationship of the second alignment mark on the driving substrate, the LED chip assembly includes a first alignment mark, a first alignment mark The mark is formed by the mark base parts grown on the same growth substrate as the LED chip, and these mark base parts can be transferred to the transient substrate together with the LED chip to form the first alignment mark on the transient substrate, avoiding the After the first alignment mark (or marking base) is set on other substrates, it is necessary to transfer the alignment mark (or marking base) and the LED chip to the transient substrate, which improves the first alignment mark on the transient substrate. The high setting efficiency is beneficial to improve the mass transfer efficiency and the production efficiency of the display panel, and improve the production efficiency.

In at least one exemplary embodiment, after the alignment is completed, it also includes: The first alignment mark is transferred from the substrate of the LED chip assembly to the driving substrate.

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated accompanying drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention.

When using a transient substrate to process LED chips (including but not limited to Micro Light-Emitting Diode (Micro-LED), Mini Light-Emitting Diode (Mini Light-Emitting Diode; Mini-LED) or During mass transfer of organic light-emitting diodes (Organic Light-Emitting Diode; OLED, etc.), it is necessary to set alignment marks on the transient substrate and the driving substrate, so as to realize the LED chip on the transient substrate and the LED chip on the driving substrate. Alignment to ensure that the LED chip can be accurately set on the drive substrate, but currently there is no solution for setting alignment marks on the transient substrate that is generally recognized in the industry.

Based on this, embodiments of the present invention provide a solution capable of solving the above technical problems, and the details thereof will be described in subsequent embodiments.

An exemplary embodiment: This embodiment first provides an LED chip assembly, including a substrate, a plurality of LED chips on the surface of the substrate, and at least two marking bases.

Wherein, the marking base part and the LED chip are on the same surface of the substrate, and the marking base part and the LED chip are formed on the same growth substrate. The marking base is used for positioning during the process of transferring multiple LED chips.

In some examples of this embodiment, the substrate in the LED chip assembly can be a growth substrate or a transient substrate. In this embodiment, "growth substrate", "transient substrate" and "drive substrate" are involved, and these types of substrates are distinguished according to the function of the substrate relative to the LED chip. Among them, the growth substrate is the substrate for growing and preparing the LED chip; the transient substrate is the substrate that transfers the LED chip from the growth substrate, and then transfers the transferred LED chip to other substrates to temporarily carry the transferred LED chip; and The driver substrate is the substrate that actually uses the LED chip, and is the chip receiver of the LED chip.

It can be understood that, in some other examples of this embodiment, the names of "growth substrate", "transient substrate" and "driving substrate" may also be replaced by other names, for example, "first substrate", " The second substrate" and "third substrate" replace the "growth substrate", "transient substrate" and "drive substrate". Alternatively, a "temporary substrate" or a "transfer substrate" may be used instead of a "transient substrate".

Firstly, the LED chip assembly including the growth substrate will be introduced below. Please refer to FIG. The marking base 13 is used to form at least two first alignment marks on the transient substrate after being transferred onto the transient substrate. The first alignment mark is used to cooperate with the second alignment mark on the driving substrate to achieve alignment between the transient substrate and the driving substrate, thereby ensuring that the LED chip on the transient substrate is aligned with the chip installation area on the driving substrate. In this embodiment, the LED chip 12 and the marking base 13 are located on the same surface of the growth substrate 11 , and both are grown from the surface of the growth substrate 11 .

In some examples of this embodiment, at least part of the material of the marking base part 13 is the same as at least part of the material of the LED chip 12 . That is, assuming that the material set of the material forming the marking base 13 is the first set S1 , and the material set of the material forming the LED chip 12 is the second set S2 , there is an intersection between the first set S1 and the second set S2 .

In some examples, the first set S1 may be a subset of the second set S2, that is, the second set S2 includes the first set S1. It should be understood that the first set S1 is a subset of the second set S2, which includes the case where the first set S1 is a proper subset of the second set S2, and at this time, the marking base 13 can be formed from a portion of the LED wafer 12 Material formation; meanwhile, it also includes the case that the first set S1 and the second set S2 are equal, at this time, the marking base 13 can be formed from all the materials that form the LED chip 12 .

In some examples of this embodiment, the marking base member 13 is a composite layer structure including multiple layer structures, the continuous n layer structures in the marking base member 13 can constitute the first partial layer, and the continuous n layers in the LED chip 12 The structure can constitute the second partial layer, where the value of n is greater than or equal to 2. In this embodiment, the forming material of the first partial layer is the same as that of the second partial layer, and the relative position of the layer structure of the same forming material in the first partial layer is the same as that in the second partial layer. For example, it is assumed that the marking base member 13 includes three adjacent layer structures whose materials are respectively b1, b2, and b3, and the layers b1, b2, and b3 are arranged sequentially from bottom to top. At the same time, the LED chip 12 also includes layers b1, b2, and b3, and the lower surface and upper surface of the b2 layer are bonded to the b1 layer and the b3 layer respectively. It can be seen that the b1 layer, b2 layer and b3 layer in the marking base member 13 can constitute the first partial layer, while the b1 layer, b2 layer and b3 layer in the LED chip 12 can constitute the second partial layer.

In some examples of this embodiment, all the layer structures of the marking base member 13 exist in the LED wafer 12, and all the layer structures of the marking base member 13 can be used as the first partial layer. In the LED chip 12 , the second partial layer corresponding to the first partial layer may be constituted by all the layer structures, or a layer structure not present in the marking base material 13 may be included in addition to the second partial layer. In one example, as shown in FIG. 2 , the marking base member 13 includes a marking sacrificial layer 131 , a marking first semiconductor layer 132 , a marking active layer 133 , a marking second semiconductor layer 134 and a marking current spreading layer from bottom to top. 135, while the LED chip 12 includes a wafer sacrificial layer 121, a wafer first semiconductor layer 122, a wafer active layer 123, a wafer second semiconductor layer 124, and a wafer current spreading layer 125 from bottom to top. In addition, the LED wafer 12 also includes It includes a wafer metal layer 126 connected to the wafer current spreading layer 125 and the wafer first semiconductor layer 122 respectively. In FIG. 2 , the marking base 13 does not include a metal layer, but in some other examples, the marking base 13 may also include a metal layer.

It can be understood that the marking base member 13 may not form the first alignment mark on the growth substrate 11 , especially when the first alignment mark needs to be formed by splicing two or more marking base members. Therefore, in some examples, the relative positional relationship between the marking base 13 and the LED die 12 on the growth substrate 11 may be different from the relative positional relationship after being transferred onto the transient substrate. In the present embodiment, the specific position of the marking base part 13 on the growth substrate 11 is not even limited, and, in the case of selecting the dead point LED wafer as the marking base part 13, because the appearance position of the dead point LED chip is random Therefore, the position of the marking base part 13 cannot be specified.

Of course, there are also some examples where the position of the marking base member 13 on the growth substrate 11 can be controlled. For example, when the marking base member 13 is specially formed on the growth substrate, in order to avoid affecting the growth of the LED wafer 12, it can be placed on the growth substrate 11 wafer. The free area outside the growth area forms the marking base. For example, in FIG. 1 , the marking base 13 is located outside the growth substrate 11 because the central region of the growth substrate 11 is the wafer growth region.

In this embodiment, the shape of the marking base part 13 is not limited. For example, in some examples, the marking base part 13 is a cuboid or a cube, that is, the cross section of the marking base part 13 is a rectangle. In an example, the marking base 13 is cylindrical, and its cross section is circular. Alternatively, the cross-section of the marking base 13 may be triangular, and the whole may be in the shape of a triangular prism. In some other examples, the cross-section of the marking base 13 may be polygonal (such as hexagon, regular octagon, etc.), or the cross-section of the marking base 13 may be an irregular shape.

In the above examples, the structure of the marking base 13 is relatively similar to the LED chip 12 , but the marking base 13 is still slightly different from the LED chip 12 . However, in some other examples of this embodiment, the marking base 13 may include LED wafers grown from the growth substrate 11. For example, after the growth of the LED wafers is completed, at least two of the LED wafers may be arbitrarily designated as The marking base part, or at least two LED chips can be selected from a plurality of LED chips as the marking base part according to a certain principle. In some examples, one marking base component may be one LED chip, and in some other examples of this embodiment, one marking base component may also include two or more LED chips.

In this exemplary embodiment, the LED chip included in the marking base part 13 may be a dead point LED chip. After the growth of the LED chip on the growth substrate 11 is completed, the LED chip is usually tested to determine that the quality is not up to standard. LED chips or LED chips with faults, these LED chips are bad LED chips. In the case of using LED chips with dead pixels, the LED chips with dead pixels that have no value in use can be utilized, thereby improving the utilization rate of the LED chips grown on the growth substrate 11 .

In some other examples of this embodiment, LED wafers at certain positions on the growth substrate 11 can be designated as the marking base 13, whether good or bad. For example, when the wafer growth area on the growth substrate 11 is rectangular, it can be designated The four LED chips at the apices of the rectangle are used as the marking base part 13 . It can be understood that although in this scheme of setting the marking base part 13, the LED chip as the marking base part 13 may be a good-quality LED chip, the bad point LED chip still cannot be utilized, but this formation of the marking base part The solution of 13 can also reduce the time cost and process cost of forming the marking base part 13. After all, the LED chips are produced in batches on the growth substrate 11, so the formation of the marking base part 13 does not need to prepare additional materials or use additional preparation processes. .

This embodiment also provides another LED chip assembly including a transient substrate, as shown in FIG. 3 : the LED chip assembly includes a transient substrate 31, a plurality of LED chips 12 and at least two first alignment marks 33, The relative positional relationship between a pair of alignment marks 33 and the LED chip 12 is the same as that of the second alignment mark on the drive substrate and the wafer setting area. Therefore, as long as each first alignment mark 33 and the corresponding second pair If the bit marks are aligned, the LED chip 12 can be aligned with the chip setting area on the drive substrate.

In this embodiment, the first alignment mark 33 includes a marking base part, and in some examples, a first alignment mark 33 is only composed of one marking base part, but in some other examples of this embodiment, the first alignment mark A pair of positioning marks 33 can also be formed by splicing two or more marking base pieces. In some examples, only two first alignment marks 33 may be set on the transient substrate 31. For example, in these examples, a plurality of LED chips 12 on the transient substrate 31 are arranged in a rectangle, and the two The first alignment mark 32 can be arranged outside the same side of the rectangle, or the two first alignment marks 33 are respectively arranged at the diagonal vertex attachment of the rectangle, and both are on the extension line of the diagonal of the rectangle, see Fig. 4. In some examples of this embodiment, four first alignment marks 33 may be provided on the transient substrate 31, and these four first alignment marks 33 are respectively located at the vertices of the rectangle formed by the arrangement of the LED chips, please Continuing to refer to FIG. 3 , the face shapes between the four first alignment marks can also form a rectangle, but the area of the rectangle is slightly larger than the area of the rectangle formed by the LED chips 12 . Undoubtedly, in some other examples of this embodiment, the number of the first alignment marks 33 in the LED chip assembly can also be other values, for example, it can be 3, 5 or even more.

In this embodiment, the marking base part on the transient substrate 31 in this embodiment is transferred from the growth substrate of the LED chip 12 , that is, the marking base part and the LED chip 12 come from the same growth substrate. For example, in some examples, the LED wafer 12 on the transient substrate 31 may be part of the LED wafer 12 on the growth substrate 11; Marking on the base 13. Therefore, the structure of the marking base on the transient substrate 31 can refer to the introduction of the marking base 13 on the growth substrate 11, for example, in some examples, at least part of the material of the marking base is the same as at least part of the material of the LED chip 12; In some examples, the marking base includes a plurality of layer structures, and the continuous n layer structures in the multiple layer structures constitute the first partial layer, and the continuous n layer structures in the LED wafer 12 constitute the second partial layer, and n is greater than or equal to 2 ; the forming material of the first sub-layer is the same as the forming material of the second sub-layer, and the layer structure of the same forming material is in the same relative position in the first sub-layer as in the second sub-layer; in some examples, the marking base The parts can include LED chips, and the LED chips used as the marking base parts can be LED chips with up to standard quality, or LED chips with dead pixels. The specific structure of the marking base parts and the advantages of various structures will not be repeated here.

In an example of this embodiment, the first alignment mark 33 includes a three-dimensional pattern formed by splicing at least two marking base pieces. It can be understood that when the first alignment mark 33 is made of an LED chip, in order to be able to visually distinguish the LED chip as the marking base part from the LED chip as the transferred target device, the LED chip as the marking base part Splicing into some special patterns, for example, multiple LED chips are arranged side by side to form a rectangular pattern, multiple LED chips are spliced into a "ten" pattern, or multiple LED chips are spliced into a pattern similar to flowers, etc., so that it can be clearly The LED chip in the first alignment mark 33 is distinguished from other LED chips.

In addition, in this embodiment, the shapes of the first alignment marks 33 may or may not be completely the same, and in some examples of this embodiment, the shapes of each first alignment mark may even be different.

This embodiment also provides a method for preparing an LED chip assembly, please refer to the flow chart of the method for preparing an LED chip assembly shown in Figure 5:

Step S502: Prepare an LED wafer on the growth substrate, and form a marking base.

When preparing the LED wafer on the growth substrate, it is necessary to grow the epitaxial layer of the LED wafer: including the N-type semiconductor layer, the active layer and the P-type semiconductor layer, etc. In some cases, it is also necessary to grow layer structures such as a buffer layer and a current spreading layer. . Subsequently, the grown layer structure can be etched to expose the electrode setting area, and then an N electrode and a P electrode are set in the electrode setting area, wherein the N electrode is electrically connected to the N-type semiconductor layer, and the P electrode is electrically connected to the P-type semiconductor layer . Those skilled in the art can understand that the electrode is electrically connected to the corresponding semiconductor layer, which does not mean that the electrode must be in contact with the corresponding semiconductor layer. For example, in some examples of this embodiment, the P electrode can be set at the current On the ITO (indium tin oxide) layer of the expansion layer, the ITO layer is electrically connected to the P-type semiconductor layer. The specific process of preparing the LED chip will not be repeated here.

In some examples of this embodiment, the marking base part is directly formed by the LED chip on the growth substrate. For example, in some examples of this embodiment, the marking base part is a dead point LED chip on the growth substrate. The basic parts can be realized in the following manner: after the LED chips are prepared, each LED chip on the growth substrate is inspected to identify the LED chips with bad spots, and then the LED chips with dead spots are used as the marking base parts. Of course, in some other examples of this embodiment, the marking base part may not be limited to LED chips with bad pixels. Select the marked base part.

In some other examples of this embodiment, the marking base is prepared using a process different from that of the LED wafer, so in this case, the structure of the marking base is not completely consistent with the structure of the LED wafer, but , the marking base part and the LED chip may have part of the same material. In some examples, there is a first sub-layer composed of continuous n layer structures in the marking base, and there is a second sub-layer composed of continuous n layer structures in the LED wafer, the first sub-layer and the second sub-layer , the forming material of the first partial layer is the same as that of the second partial layer, and the relative position of the layer structure of the same forming material in the first partial layer is the same as that in the second partial layer, in this case, forming The process of forming the layer structure of a certain material in the first sub-layer can be performed simultaneously with the process of forming the layer structure of the same material in the second sub-layer. For example, assuming that the marking base includes an N-type semiconductor layer, an active layer attached to the upper surface of the N-type semiconductor layer, and a P-type semiconductor layer attached to the upper surface of the active layer, the three layer structures in the marking base are formed The process can be carried out simultaneously with the process of forming the epitaxial layer in the LED wafer: while forming the N-type semiconductor layer in the LED wafer, the N-type semiconductor layer in the marking base is formed at the same time, and the active layer in the LED wafer is formed while forming the marking base. The active layer is formed to form the P-type semiconductor layer in the LED wafer and at the same time form the P-type semiconductor layer in the marking base.

Step S504: Transfer the LED chip and the marking base from the growth substrate to the transient substrate to obtain an LED chip assembly.

After the LED chip is grown on the growth substrate and the marking base is formed, the LED chip and the marking base can be transferred to the transient substrate to form an LED chip assembly including the transient substrate. The marking base forms the first alignment mark when it is transferred to the transient substrate. In this embodiment, the relative positional relationship between the first alignment mark and the LED chip on the transient substrate is the same as the relative positional relationship between the second alignment mark on the drive substrate and the wafer installation area. When the LED chip and the marking base are transferred to the transient substrate, it needs to be transferred based on the arrangement of the second alignment mark and the chip setting area on the driving substrate. In some cases, the LED chip is transferred from the self-growth substrate to the driving substrate. During the process, it needs to undergo the transfer of two transient substrates. The first transient substrate can directly transfer all the LED chips on the growth substrate to one of its surfaces, while the second transient substrate will The LED chips on a transient substrate are selectively transferred, so that the pitch and position of the transferred LED chips meet the requirements of the driving substrate. Therefore, in this embodiment, the transient substrate carrying the LED chip and the first alignment mark arranged in accordance with the requirements of the driving substrate is actually the second transient substrate, and the LED chip and the marking base are transferred to the transient substrate Before the substrate, it may also need to experience the transfer of another transient substrate. Here, in order to distinguish the first transient substrate and the second transient substrate from the name, it is convenient to express, so the first transient substrate is called a temporary substrate. (It can also be called intermediate substrate, transfer substrate). Of course, there are also some examples where LED wafers can be directly transferred from the growth substrate to the transient substrate without undergoing the transfer of the temporary substrate. For example, in these examples, the LED wafers can be directly transferred according to the required arrangement by using the transfer head. onto the transient substrate, and at the same time transfer the marking base to the designated position of the transient substrate, thereby forming the first alignment mark.

This embodiment also provides a method for manufacturing a display panel, please refer to the flowchart shown in FIG. 6:

Step S602: providing a driving substrate.

The provided driving substrate includes a plurality of wafer setting areas and at least two second alignment marks.

Step S604: According to the positional relationship of each second alignment mark on the driving substrate, form the LED chip assembly according to any one of the above items.

The formed LED chip assembly includes a substrate, a plurality of LED chips on the substrate, and at least two marking bases. In this exemplary embodiment, the LED chip assembly formed here is an LED chip assembly including a transient substrate. The LED chip assembly can be manufactured with reference to the process shown in FIG. 5 . Based on the foregoing introduction, it can be seen that the transient substrate not only has a plurality of LED chips, but also includes at least two first alignment marks formed by the marking base. It should be understood that the relative positional relationship between the LED chip and the first alignment mark in the LED chip assembly should be the same as the relative positional relationship between the second alignment mark on the drive substrate and the wafer installation area. Therefore, the provided LED chip assembly It must be compatible with the drive substrate. Therefore, in this embodiment, the driving substrate can be provided first, and then the LED chip assembly can be formed according to the positional relationship of the second alignment mark on the driving substrate.

It can be understood that the number of the first alignment mark and the second alignment mark can be consistent or not, for example, in some examples, the number of the two is just the same, and each first alignment mark is on the driving substrate Each has a corresponding second alignment mark, and the first alignment mark and the second alignment mark exist in pairs. Moreover, the formation of the first alignment mark and the second alignment mark constituting a mark pair is also consistent. In some other examples, the number of the first pair of alignment marks is different from that of the second pair of alignment marks, but regardless of the number, there must be at least two pairs of marks.

Step S606: Realize the alignment of the driving substrate and the LED chip assembly through the second alignment mark and the marking base.

Before transferring the LED chip in the LED chip assembly to the corresponding wafer setting area, it is necessary to use the marking base in the LED chip assembly and the second alignment mark on the driving substrate to realize the alignment of the LED chip assembly and the driving substrate: for example , the LED chip assembly includes a transient substrate and a first alignment mark formed on the transient substrate, then the first alignment mark is aligned with the corresponding second alignment mark, and this process can be performed on a CCD (Charge Coupled Device ) is automated with the aid of a camera. However, when the wafer size is large enough, it can be realized manually.

Step S608: After the alignment is completed, the LED chip is bonded to the driving substrate and peeled off from the substrate of the LED chip assembly.

Taking the transient substrate included in the LED chip assembly as an example, after the alignment between the transient substrate and the driving substrate is completed, the LED chip can be transferred from the transient substrate to the corresponding chip setting area on the driving substrate. It can be understood that in order to realize the transfer of the LED chip from the LED chip assembly to the driving substrate, on the one hand, it is necessary to realize the combination of the LED chip and the driving substrate, and on the other hand, to realize the separation of the LED chip and the substrate in the LED chip assembly. There is a driving circuit on the driving substrate. For example, in some examples, there are two solder joints in each wafer setting area, which are used to electrically connect with the two electrodes of the LED chip respectively. Therefore, after aligning the LED chip and the wafer setting area , LED chip electrodes can be bonded to solder joints in the chip setting area, and after the LED chip is bonded to the chip setting area, the LED chip and the transient substrate are separated. In some examples of this embodiment, the bonding surface of the LED chip and the transient substrate may be irradiated with laser or infrared rays, and then the transient substrate is detached.

In some examples of this embodiment, only the LED chip on the transient substrate is transferred to the driving substrate, and the first alignment mark is not transferred, but in other examples of this embodiment, the first alignment mark The mark will also be transferred to the drive substrate along with the LED chip. For example, after the transient substrate and the drive substrate are aligned through the first alignment mark and the second alignment mark, the first alignment mark can also be The driving substrate is bonded, and then the first alignment mark is separated from the transient substrate, so that the first alignment mark is transferred to the driving substrate. In this case, the resulting display panel is shown in Figure 7:

The display panel 70 includes a driving substrate 71 , a plurality of LED chips 72 , at least two first alignment marks 73 and at least two second alignment marks 74 . Wherein, a plurality of LED chips 72 are respectively arranged in each chip arrangement area on the driving substrate 71 , and are electrically connected with the driving circuit in the driving substrate 71 . It can be understood that generally all the LED chips on the driving substrate 71 do not come from the same growth substrate, so the first alignment mark 73 usually does not come from the same growth substrate as all the LED chips on the driving substrate 71, but the first pair The bit marks 73 and some LED chips are from the same growth substrate.

The second alignment mark 74 and the LED chip installation area are located on the same surface of the drive substrate. In the display panel 70, the first alignment mark 73 and the second alignment mark 74 at least partially overlap, for example, in some examples of this embodiment , the line connecting the centers of the two is perpendicular to the surface of the driving substrate, that is, the centers of the two coincide in a direction parallel to the surface of the driving substrate (those skilled in the art can understand that the centers of the two may vary depending on the process level There are certain errors due to the influence).

In some examples of this embodiment, the second alignment mark 74 is a planar pattern, but in other examples of this embodiment, the second alignment mark 74 may also be a three-dimensional structure. For example, in some examples, the second alignment mark 74 is in the shape of a hollow tube, and its cross section may be rectangular or circular. In some other examples, the second alignment mark 74 may also be a solid three-dimensional structure, such as a cuboid, a cylinder, and the like. In FIG. 7 , the cross section of the first alignment mark 73 is a rectangle, but in some other examples of this embodiment, it may also be a circle, a "cross", a "T" shape, or a triangle. Moreover, the shapes of the cross-sections of the first alignment marks 73 may not be completely the same. The contour of the cross-section of the second alignment mark 74 can also be correspondingly circular, "ten", "T", triangle, etc., as shown in Figure 8, or do not follow the cross-sectional shape of the first alignment mark The shape changes, and it is always a more regular shape such as a circle or a rectangle.

In some examples, when the second alignment mark 74 is a planar figure, the cross-sectional specification of the second alignment mark 74 can be completely consistent with the specification of the cross-section of the first alignment mark 73, but in other examples, the second The alignment mark can be different in shape or size from the first alignment mark: in one example, the cross section of the first alignment mark 73 is a square, and the cross section of the second alignment mark 74 is also a square, but the second The side length of the alignment mark is slightly longer than the first alignment mark; in one example, the cross section of the first alignment mark 73 is a circle, and the cross section of the second alignment mark 74 is a square, in this exemplary implementation In this example, the sides of the square are slightly longer than the diameter of the circle. Therefore, if the second alignment mark 74 is in the shape of a hollow tube, and the cross-sectional size of the second alignment mark 74 is larger than the cross-sectional size of the first alignment mark 73, the first alignment mark 73 will be located at the second alignment mark. 74 middle.

The LED chip assembly, display panel, and display panel manufacturing method provided in this embodiment provide a new idea of setting the first alignment mark on the transient substrate: by forming the marking base part on the growth substrate, and then placing the first alignment mark on the growth substrate The LED wafer is transferred to the transient substrate along with the marking base, allowing the marking base to form a first alignment mark. Moreover, the material of the marking base and its formation process on the growth substrate can also partially overlap with the material and formation process of the LED chip, so that the two can be produced at the same time, reducing the formation cost of the marking base and improving the setup on the transient substrate. The efficiency of the first alignment mark improves production efficiency.

Another exemplary embodiment of the invention:

In order to make those skilled in the art more aware of the advantages and details of the LED chip assembly including the growth substrate, the LED chip assembly including the transient substrate, the display panel and the corresponding manufacturing method provided by the embodiment of the present invention, this embodiment will combine examples Continuing to explain the foregoing method, it can be understood that since the process of preparing the display panel includes the formation process of two kinds of LED chip assemblies, this embodiment is introduced in combination with the manufacturing process of the display panel, please refer to FIG. 9 A manufacturing flow chart of a display panel and a schematic diagram of process state changes shown in FIG. 10:

Step S902: Prepare an LED chip on the growth substrate, and form a marking base.

In this exemplary embodiment, the growth substrate 101 may be a sapphire wafer.

In this embodiment, the structure of the marking base 103 is different from that of the LED chip 102, so the marking base 103 needs to be formed separately. Figure 11 shows a schematic cross-sectional view of the marking base part 103 and the LED chip 102: the marking base part 103 includes a weakened structure layer and an epitaxial layer from bottom to top (the first semiconductor layer, the active layer and the first semiconductor layer from bottom to top). second semiconductor layer), an ITO layer and a silicon oxide layer. At the same time, the marking base member 103 also includes a metal layer disposed on the ITO layer after etching the silicon oxide layer; the LED chip 102 includes a weakened structure layer and an epitaxial layer in sequence from bottom to top (From bottom to top are the first semiconductor layer, active layer and second semiconductor layer), ITO layer and silicon oxide layer. At the same time, the LED chip 102 also includes a second electrode disposed on the ITO layer after etching the silicon oxide layer and the first electrode disposed on the first semiconductor layer after sequentially etching the silicon oxide layer, the ITO layer, the second semiconductor layer and the active layer. It can be seen from FIG. 11 that, compared with the formation process of the LED chip 102, the formation process of the marking base member 103 lacks the process of setting the first electrode. Therefore, compared with the LED chip 102, the marking base 103 has less etched area, and also has one less metal layer. In some other examples of this embodiment, the marking base part 103 can also have a layer structure that the LED chip 102 does not have, or the marking base part 103 has the same layer structure as the LED chip 102, but the difference between the layer structure and the layer structure The location relationship is different.

It can be understood that, after growing and forming the LED chip 102 and the marking base 103 on the growth substrate 101 , the LED chip assembly including the growth substrate, the LED chip and the marking base has been formed, please refer to (a) in FIG. 10 .

Step S904: Transfer the LED chip and the marking base from the growth substrate to the temporary substrate.

In this embodiment, after the LED chip 102 and the marking base 103 are grown on the growth substrate 101 , the LED chip 102 and the marking base 103 can be transferred to the temporary substrate 104 together. In this exemplary embodiment, the surface of the temporary substrate 104 with an adhesive layer is used to approach the growth substrate 101 until the LED chip 102 and the marking base 103 are adhered to the temporary substrate 104, and then the growth substrate 101 is removed by laser lift-off. , as shown in Figure 10(b).

In this embodiment, both the LED chip 102 and the marking base 103 on the growth substrate 101 are transferred to the temporary substrate 104 .

Step S906: providing a driving substrate and a second alignment mark disposed on the driving substrate.

In this embodiment, the second alignment mark 107 is a three-dimensional structure, and the shape of the cross section of the second alignment mark 107 is a rectangle, which is the same as the shape of the cross section of the first alignment mark 106, but the second alignment mark 107 The size of the cross section is larger than the size of the cross section of the first alignment mark 106 , as shown in FIG. 10( c ).

It can be understood that the driving substrate 108 and the second alignment mark 107 disposed on the driving substrate 108 can be prepared before the formation of the LED chip assembly including the transient substrate, for example, in this embodiment, including the transient substrate The LED chip assembly is formed according to the positional relationship of the second alignment mark on the driving substrate, so the driving substrate should be provided first, and then the LED chip assembly is formed. Of course, the positional relationship between the second alignment mark (or the first alignment mark) can also be determined in advance, and then the LED chip assembly and the driving substrate are prepared according to the determined positional relationship. In this case, the LED chip assembly It can be formed before the driving substrate, and the two preparation processes can also be carried out at the same time.

Step S908: Selectively transfer the LED chip to the transient substrate according to the positional relationship between the chip installation area on the driving substrate and the second alignment mark, and transfer the marking base part to the transient substrate to form the first alignment mark.

When transferring the LED chip 102 and the marking base 103 from the temporary substrate 104, it is selectively transferred. Only part of the LED chip 102 on the temporary substrate 104 will be transferred to the transient substrate 105, and after the transfer, each LED chip The pitch of is also different from that on the temporary substrate 104 . In addition, the marking base part will also be transferred to a specific position of the transient substrate 105 to form the first alignment mark 106. In this embodiment, a first alignment mark 106 is only composed of a marking base part 103, and the transient substrate Four first alignment marks 106 need to be set on 105 , therefore, only four mark base parts 103 can be transferred from the temporary substrate 104 on the transient substrate 105 , and even only four mark base parts 103 can be grown on the growth substrate 101 .

It can be understood that after the LED chip 102 and the marking base 103 are transferred to the transient substrate 105 according to the corresponding arrangement requirements, the LED chip assembly including the transient substrate, the LED chip and the first alignment mark has been formed. As shown in Figure 10(d).

Step S910: Realize the alignment of the transient substrate and the driving substrate through the first alignment mark and the second alignment mark.

Align the first alignment mark 106 with the corresponding second alignment mark 107 , and then realize the alignment of the transient substrate 105 and the driving substrate 108 , as shown in FIG. 10( e ).

Step S912: bonding the LED chip, the first alignment mark and the driving substrate.

In this embodiment, both the LED chip 102 and the first alignment mark 106 will be transferred to the drive substrate 108. Therefore, align the LED chip 102 with the corresponding wafer installation area, and align the first alignment mark 106 with the second alignment mark. After marking 107 , the LED chip 102 and the first alignment mark 106 can be bonded to the driving substrate 108 to realize the electrical connection between the LED chip 102 and the driving circuit in the driving substrate 108 . After the first alignment mark 106 is bonded to the driving substrate 108 , its center will coincide with the center of the second alignment mark 107 , as shown in FIG. 10( f ).

In some examples of this embodiment, the first alignment mark 106 may not be transferred to the driving substrate 108 , so in these examples, it is not necessary to bond the first alignment mark 106 and the driving substrate 108 .

Step S914: peeling off the transient substrate.

After bonding the LED chip 102, the first alignment mark 106 and the drive substrate 108, the combination between the LED chip 102 and the transient substrate 105, and the first alignment mark 106 and the transient substrate can be contacted by laser or infrared rays. 105 to realize the peeling of the transient substrate 105, please refer to FIG. 10(g).

After all the LED chips required by the display panel are transferred by the above transfer method, the display panel 10 is basically formed. In some examples, a protective layer for protecting the LED chips on the driving substrate 108 may be further provided.

In the display panel preparation scheme provided in this embodiment, in the process of preparing the display panel, in order to realize the transfer of the LED chip from the transient substrate to the driving substrate, the marking base can be formed on the growth substrate at the same time during the growth process of the LED chip . When transferring the LED chip to the transient substrate, the marking base is also transferred to form the first alignment mark corresponding to the second alignment mark on the drive substrate, and then use the first alignment mark and the second alignment mark The alignment of the mark realizes the alignment of the LED chip and the chip setting area in the driver substrate, and improves the quality of the display panel. In this embodiment, since the marking base of the first alignment mark on the transient substrate and the LED chip on the transient substrate can come from the same growth substrate, the marking base can be transferred to the transient state along with the LED wafer. On the substrate, the first alignment mark on the transient substrate is formed, which avoids the problem of transferring the first alignment mark and the LED chip to the transient substrate after setting the first alignment mark on other substrates, and improves the temporary The setting efficiency of the first alignment mark on the state substrate is conducive to improving the mass transfer efficiency and the manufacturing efficiency of the display panel, and improving the production efficiency.

It should be understood that the application of the present invention is not limited to the above-mentioned examples, and those of ordinary skill in the art can improve or change according to the above description, and all these improvements and changes should belong to the scope of protection of the appended patent scope of the present invention .

10: LED chip assembly 11: Growth substrate 12: LED chip 13: Mark the basic parts 121: wafer sacrificial layer 122: The first semiconductor layer of the wafer 123: Wafer active layer 124: The second semiconductor layer of the wafer 125: chip current spreading layer 126: Wafer metal layer 131: Mark the sacrificial layer 132: Mark the first semiconductor layer 133: mark the active layer 134: Mark the second semiconductor layer 135:Mark the current expansion layer 30: LED chip assembly 31: Transient Substrate 33: The first alignment mark 70: Display panel 71:Drive substrate 72:Multiple LED chips 73: The first alignment mark 74: Second alignment mark 101: Growth substrate 102:LED chip 103: Mark the basic parts 104:Temporary substrate 105:Transient Substrate 106: The first alignment mark 107: Second alignment mark 108: Drive substrate S502~S504: steps S602~608: steps S902~S914: steps

1 is a schematic diagram of an LED chip assembly including a growth substrate provided in an exemplary embodiment of the present invention; Fig. 2 is a schematic diagram of an optional structure of an LED chip and a marking base provided in an exemplary embodiment of the present invention; 3 is a schematic diagram of an LED chip assembly including a transient substrate provided in an exemplary embodiment of the present invention; 4 is another schematic diagram of an LED chip assembly including a growth substrate provided in an exemplary embodiment of the present invention; Fig. 5 is a flow chart of preparing an LED chip assembly including a transient substrate provided in an exemplary embodiment of the present invention; Fig. 6 is a flow chart of preparing a display panel provided in an exemplary embodiment of the present invention; Fig. 7 is a schematic diagram of a display panel provided in an exemplary embodiment of the present invention; FIG. 8 is another schematic diagram of a display panel provided in an exemplary embodiment of the present invention; Fig. 9 is a flow chart of preparing a display panel provided in another exemplary embodiment of the present invention; FIG. 10 is a schematic diagram of a process state change of the display panel in FIG. 9; Fig. 11 is a schematic diagram of an optional structure of an LED chip and a marking base provided in another exemplary embodiment of the present invention.

S502~S504: steps

Claims (8)

An LED chip assembly, comprising: a substrate; a plurality of LED chips located on the surface of the substrate; and at least two marking bases; wherein, the marking bases and the LED chips are on the same surface of the substrate, and The marking base part and the LED wafer are formed on the same growth substrate; the marking base part is used for positioning during the process of transferring a plurality of the LED wafers, wherein the marking base part includes a dead pixel LED Wafer, or using materials that form at least part of the layer structure of the LED chip to grow the marking base member in the idle area of the growth substrate, wherein the idle area is an area other than the wafer growth area on the growth substrate . The LED chip assembly according to claim 1, wherein at least part of the material of the marking base is the same as at least part of the material of the LED chip. The LED chip assembly according to claim 2, wherein the marking base member includes a plurality of layer structures, and the continuous n layer structures in the plurality of layer structures form the first partial layer, and the continuous n layer structures in the LED chip Two layer structures constitute the second partial layer, the n is greater than or equal to 2; the forming material of the first partial layer is the same as that of the second partial layer, and the layer structure of the same material is in the first partial layer The relative position is the same as in the second partial layer. The LED chip assembly according to any one of claims 1 to 3, wherein the substrate comprises a growth substrate or a transient substrate. A method for preparing an LED chip assembly, comprising the following steps: preparing an LED wafer on a growth substrate, and forming a marking base; and transferring the LED wafer and the marking base from the growth substrate to a transient substrate, to obtain LED chip assembly; the marking base part is used to play a positioning role in the process of transferring the LED chip from the transient substrate to the driving substrate, wherein the formation of the marking base part is realized by one of the following methods: Mode 1 : using materials forming at least part of the layer structure of the LED chip to grow the marking base member in the idle area of the growth substrate; wherein, the idle area is an area other than the wafer growth area on the growth substrate; and Method 2: After the LED chip is prepared, the LED chip is inspected to identify the LED chip with dead spots, and the LED chip with dead spots is used as the marking base. A display panel, comprising: a driving substrate; a plurality of LED chips arranged in a chip arrangement area of the driving substrate and electrically connected to a driving circuit in the driving substrate; and at least two marking bases , the marking base part is grown and formed on the same growth substrate as part of the plurality of LED chips, and transferred to the driving substrate through the same transient substrate; the marking base part is used for transferring from the transient substrate to the The driving substrate plays a positioning role in the process of transferring the LED chip, wherein the marking base member includes the bad pixel LED chip grown on the growth substrate, or adopts at least a partial layer structure that forms the LED chip The material grows on the idle area of the growth substrate to form the marking base member, wherein the idle area is an area other than the wafer growth area on the growth substrate. A method for manufacturing a display panel, comprising the following steps: providing a driving substrate; wherein at least two second alignment marks are formed on the driving substrate; according to the positions of the second alignment marks on the driving substrate, relationship, forming the LED chip assembly as described in any one of claims 1 to 4; realizing the alignment of the driving substrate and the LED chip assembly through the second alignment mark and the marking base; and After the position alignment is completed, the LED chip is bonded to the driving substrate and peeled off from the substrate of the LED chip assembly. The display panel manufacturing method according to claim 7, further comprising the following step after the alignment is completed: transferring the marking base member from the substrate of the LED chip assembly to the driving substrate.

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