Miniature light-emitting chip test method and test module

Abstract

The invention relates to a miniature light-emitting chip testing method and a testing module. The miniature light-emitting chip testing method comprises the following steps: providing a chip substrate provided with a plurality of miniature light-emitting chips; providing a detection substrate; transferring a large amount of micro light-emitting chips to a detection substrate, arranging each transferred micro light-emitting chip on a conductive unit, electrically connecting an electrode of the micro light-emitting chip with a pair of lead-out parts, and enabling each lead-out part to have an exposed bonding area on the transferred micro light-emitting chip; dividing the detection substrate into a plurality of test modules of which the sizes are larger than those of the micro light-emitting chips; performance detection is carried out on the test modules one by one, and in the performance detection process, the test circuit is electrically connected with the micro light-emitting chip through the bonding area. In some embodiments, detection of a single miniature light-emitting chip can be completed with low cost and simple processes.

Description

Technical Field

[0001] The present application relates to the field of chip testing, and in particular to a micro-light-emitting chip testing method and a testing module. Background Art

[0002] The Micro LED (Micro Light Emitting Diode) display panel is composed of an array of micron-scale semiconductor light-emitting chips. It is a comprehensive technology that integrates new display technology and LED (Light Emitting Diode) technology. It has the advantages of self-luminescence, high efficiency, low power consumption, high integration, high stability, and all-weather operation.

[0003] Due to the small chip size of micro LEDs, micro LED wafers cannot be cut into individual chips. In the actual development of micro LEDs, it is impossible to test the performance of a single micro LED in a similar way to the Mini LED (Mini Light Emitting Diode) chip. Due to the lack of performance data for a single micro LED, the performance optimization of micro LED products requires the use of a TFT (Thin Film Transistor) backplane after mass transfer, which is very costly and has a long process cycle.

[0004] Therefore, how to obtain the performance data of a single micro-LED at low cost is an urgent problem to be solved. Summary of the invention

[0005] In view of the deficiencies of the above-mentioned related technologies, the purpose of this application is to provide a micro-light-emitting chip testing method and a testing module, aiming to solve the problem that the performance optimization of micro-light-emitting diode products requires the use of a TFT backplane after mass transfer, which has high costs and long process cycles.

[0006] A micro-light emitting chip testing method, comprising:

[0007] Providing a chip substrate, on which a plurality of micro light-emitting chips are arranged;

[0008] Providing a detection substrate, the detection substrate comprising a plurality of conductive units corresponding to the micro-light-emitting chip, each of the conductive units comprising a pair of insulated lead-out portions;

[0009] Transferring the micro-light-emitting chips in bulk to the detection substrate, wherein each transferred micro-light-emitting chip is disposed on one of the conductive units, and the electrodes of the micro-light-emitting chips are electrically connected to a pair of the lead-out portions, and each of the lead-out portions has an exposed bonding area after the transfer of the micro-light-emitting chips;

[0010] Dividing the detection substrate into a plurality of test modules having a size larger than the micro-light-emitting chip, each of the test modules comprising a conductive unit and the micro-light-emitting chip located on the conductive unit;

[0011] The test modules are subjected to performance testing one by one. During the performance testing process, the test circuit is electrically connected to the micro light-emitting chip through the bonding area.

[0012] The above-mentioned micro-light-emitting chip testing method, by means of mass transfer and then splitting the detection substrate, forms the micro-light-emitting chip that is difficult to operate as a single unit into a larger and individually independent test module, which is easier to enter the subsequent detection process. In some embodiments, the detection of a single micro-light-emitting chip can be completed.

[0013] Optionally, the step of performing performance testing on the test modules one by one includes:

[0014] Providing at least two test jig substrates corresponding to different test items, each of which is provided with a test circuit;

[0015] The different test modules are respectively arranged on the test jig substrate of different test items, and each of the lead-out parts is correspondingly connected to the test circuit;

[0016] The corresponding micro light-emitting chips are driven by the test circuits on different test jig substrates to perform at least two different performance tests.

[0017] Different test modules are respectively set on the test jig substrates required for different test items to achieve the purpose of testing different performances of the micro-light-emitting chip. In some implementations, parallel testing can be performed, and the test efficiency is high.

[0018] Optionally, the test module is a quadrilateral with a shortest side not less than 100 um and a longest side not greater than 500 um.

[0019] A plurality of test modules can be formed on the same detection substrate, and the size of each test module can be easily operated individually, which avoids the situation that a single micro light-emitting chip is too small to be detected individually in some implementation processes.

[0020] Optionally, each of the lead-out portions includes a die-bonding region directly connected to the electrode of the micro-light-emitting chip, and a pad region connected to the die-bonding region, the pad region is larger than the die-bonding region, and the pad region is any one of the following:

[0021] A quadrilateral with the shortest side not less than 100um and the longest side not more than 300um;

[0022] A circle with a radius not less than 100um and not more than 300um.

[0023] In some implementations, the pad area can be electrically connected using traditional methods such as wire bonding, eliminating the need for a traditional TFT backplane to drive the micro-light-emitting chip array, thereby achieving simpler and lower-cost detection of a single micro-light-emitting chip.

[0024] Optionally, in each pair of the lead-out portions, a distance between two of the lead-out portions is greater than a distance between two of the electrodes on the micro light-emitting chip.

[0025] The slightly larger spacing between the lead-out parts can reduce the accuracy requirements of subsequent processing, and when the bonding material between the micro light-emitting chip and the detection substrate overflows, it is not easy to short-circuit directly because of the larger insulation spacing between the two lead-out parts.

[0026] Based on the same inventive concept, the present application also provides a test module, including:

[0027] A sub-base formed by dividing the detection base plate, the sub-base plate comprising a conductive unit, the conductive unit comprising a pair of insulated lead-out portions;

[0028] A micro-light-emitting chip is arranged on the conductive unit, and the size of the sub-substrate is larger than that of the micro-light-emitting chip; the electrodes of the micro-light-emitting chip are electrically connected to a pair of the lead-out parts, and each of the lead-out parts has an exposed bonding area after the micro-light-emitting chip is arranged, and the bonding area is used to electrically connect the test circuit with the micro-light-emitting chip during the performance detection process.

[0029] The micro-light-emitting chips that are difficult to operate individually are formed into larger and independent test modules, which are easier to enter the subsequent detection process. By using the test module of the present application, the detection of a single micro-light-emitting chip set thereon can be completed in some implementation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the basic process of testing a micro-light-emitting chip provided in an embodiment of the present application;

[0031] Figure 2 Schematic diagram of the correspondence between the conductive unit and the micro light-emitting chip provided in the embodiment of the present application Figure 1 ;

[0032] Figure 3 Schematic diagram of the correspondence between the conductive unit and the micro light-emitting chip provided in the embodiment of the present application Figure 2 ;

[0033] Figure 4 A schematic diagram of the spacing between a lead-out portion and an electrode of a micro light-emitting chip provided in an embodiment of the present application;

[0034] Figure 5 A schematic diagram of the structure of a test module provided in an embodiment of the present application;

[0035] Figure 6 A schematic diagram of a flow chart for performing performance testing of test modules one by one according to an embodiment of the present application;

[0036] Figure 7 Another schematic diagram of a process for performing performance testing on test modules one by one provided in an embodiment of the present application;

[0037] Figure 8 A schematic diagram of a process for manufacturing a detection substrate provided in an embodiment of the present application;

[0038] Fig. 9 A schematic diagram of the structure of a detection substrate provided in an embodiment of the present application;

[0039] Fig.10 A schematic diagram of the process of manufacturing a micro light-emitting chip provided in an embodiment of the present application;

[0040] Fig.11 A schematic diagram of the manufacturing process of a micro light-emitting chip provided in an embodiment of the present application;

[0041] Fig.12 Another schematic diagram of a process for testing a micro-light-emitting chip provided in an embodiment of the present application;

[0042] Fig.13 A schematic diagram of the bonding of a growth substrate and a detection substrate provided in an embodiment of the present application;

[0043] Fig.14 A schematic diagram of a detection substrate provided in an embodiment of the present application and provided with a micro-light-emitting chip;

[0044] Fig.15 A schematic diagram of a structure in which a test module provided in an embodiment of the present application is arranged on a test jig substrate;

[0045] Description of reference numerals:

[0046] 1-detection substrate; 11-test module; 2-conductive unit; 21-lead-out portion; 22-conductive through hole; 211-solidification area; 212-pad area; 3-chip substrate; 31-growth substrate; 4-micro light-emitting chip; 41-electrode; 42-N-type semiconductor layer; 43-active layer; 44-P-type semiconductor layer; 45-transparent conductive layer; 46-passivation layer; 5-test jig substrate; 51-test circuit; 52-conducting wire. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented 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 application more thoroughly and comprehensively understood.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0049] In the related art, the performance optimization of micro light-emitting diode products requires the use of a TFT backplane after mass transfer, which is very costly and has a long process cycle.

[0050] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0051] See also Figure 1 This embodiment provides a micro-light emitting chip testing method, which includes but is not limited to the following steps:

[0052] S101, providing a chip substrate, on which a plurality of micro light-emitting chips are arranged;

[0053] The micro-light-emitting chip 4 in the present application refers to a light-emitting chip with a size less than 100um, which can be a Micro LED chip or a Mini LED chip. The chip substrate 3 can be a growth substrate 31 on which an epitaxial layer is grown and an epitaxial layer is fabricated to form a micro-light-emitting chip 4. The material can be a semiconductor material capable of growing an epitaxial layer of the micro-light-emitting chip 4. For example, the material of the growth substrate 31 can be but not limited to sapphire, silicon carbide, silicon, gallium arsenide, or other semiconductor materials, which are not limited here. The chip substrate 3 can also be a substrate other than the growth substrate 31 on which the micro-light-emitting chip 4 can be provided. For example, the micro-light-emitting chip 4 is transferred from the growth substrate 31 to a temporary substrate for temporary storage. The material of these substrates can be but not limited to sapphire, glass, etc. In practical applications, based on the manufacturing process and the process of mass transfer, these micro-light-emitting chips 4 are usually arranged on the chip substrate 3 in a relatively dense array.

[0054] S102, providing a detection substrate, the detection substrate comprising a plurality of conductive units corresponding to the micro light-emitting chips, each conductive unit comprising a pair of lead-out portions;

[0055] The detection substrate 1 can be made of insulating materials such as sapphire, glass, silicon wafer, etc., at least on the surface. The conductive unit 2 on the detection substrate 1 can be in the form of a graphical conductive circuit, and its material can be at least one of conductive metals including but not limited to Cr, Ni, Al, Ti, Au, Pt, W, Pb, Rh, Sn, Cu, Ag, etc. The conductive unit 2 includes a pair of insulated lead-out portions 21. It should be noted that the lead-out portions 21 can also conduct electricity, but the two lead-out portions 21 of the same conductive unit 2 are not electrically connected, and there is a certain insulating gap between them. The lead-out portion 21 of the conductive unit 2 is used to connect to the two electrodes 41 of the micro-luminescent chip, and in the present application, the lead-out portion 21 is also used to connect to the test circuit 51, that is, the size of the lead-out portion 21 is larger than the size of the electrode 41 of the micro-luminescent chip to be tested. After the micro-luminescent chip is set on the detection substrate 1, it cannot completely block the lead-out portion 21. A single lead-out portion 21 may be disposed on one side of the detection substrate 1 , or may be formed on both sides of the detection substrate 1 by penetrating the detection substrate 1 through a conductive through hole 22 .

[0056] S103, transferring a large number of micro-light-emitting chips to a detection substrate;

[0057] Since the micro-light emitting chip 4 is small in size and cannot be operated individually, the micro-light emitting chip 4 is arranged in a mass transfer manner in this embodiment. It can be understood that the conductive unit 2 in this embodiment is formed according to the arrangement and size specifications of the micro-light emitting chip 4 on the chip substrate 3. Figure 2As shown, the conductive unit 2 corresponds to the micro-light emitting chip 4 on the chip substrate 3, and the arrangement rules of the two are completely consistent, and the position of the lead-out portion 21 is also corresponding to the position of the electrode 41 of the micro-light emitting chip 4. The number of the conductive unit 2 and the micro-light emitting chip 4 on the chip substrate 3 can be different, for example Figure 3 As shown, in order to leave a larger area for setting a larger area of ​​the lead-out portion 21, the conductive units 2 can be arranged relatively sparsely, so that each interval of a micro-light-emitting chip 4 corresponds to a conductive unit 2. In this way, the mass transfer process of the micro-light-emitting chips 4 can have a certain selectivity, that is, only the part of the micro-light-emitting chips 4 corresponding to the conductive unit 2 is transferred to the detection substrate 1. When a single detection substrate 1 cannot receive all the micro-light-emitting chips 4, two or more detection substrates 1 can be used to transfer the micro-light-emitting chips 4 on the chip substrate 3 to different detection substrates 1.

[0058] The mass transfer method of the micro-light-emitting chip 4 may include laser transfer, stamp transfer, etc., but in this embodiment, in order to ensure the electrical connection of a single micro-light-emitting chip 4, after the micro-light-emitting chip 4 is transferred to the detection substrate 1, the electrode 41 should be electrically connected to a pair of lead-out portions 21, that is, the electrode 41 falls on the lead-out portion 21. However, it can be understood that in this application, one electrode 41 is only connected to one of the lead-out portions 21, and the other electrode 41 is connected to the other of the lead-out portions 21. Therefore, in some mass transfer processes, such as stamp transfer, it is necessary to pre-adjust the orientation of the electrode 41 of the micro-light-emitting chip 4.

[0059] like Figure 2 and Figure 3 As shown, the size of the lead-out portion 21 is larger than the size of the electrode 41 of the micro-light-emitting chip to be tested, and in this embodiment, at least the electrode 41 of the micro-light-emitting chip 4 will shield the lead-out portion 21. In actual applications, the shielding of the lead-out portion 21 by the micro-light-emitting chip 4 is not limited to the electrode 41. In order to realize the driving and lighting of the micro-light-emitting chip 4 to complete the test, each lead-out portion 21 still has an exposed portion as a bonding area after the micro-light-emitting chip 4 is transferred.

[0060] In some embodiments, the area of ​​the region exposed by each lead-out portion 21 after the micro-light-emitting chip 4 is transferred can still be larger than the area of ​​a single electrode 41 of the micro-light-emitting chip 4. This will enable the micro-light-emitting chip 4 to be transferred to the detection substrate 1 and to achieve external electrical connection through the lead-out portion 21. The lead-out portion 21 increases the area that can be connected and reduces the difficulty of establishing an electrical connection with a single micro-light-emitting chip 4.

[0061] In some embodiments, see Figure 4, the interval d1 between the two lead-out portions 21 in each pair of lead-out portions 21 is greater than the interval d2 between the two electrodes 41 on the micro-light-emitting chip 4. In practical applications, setting a slightly larger interval between the lead-out portions 21 can reduce the accuracy requirements of subsequent processing. For example, the position deviation of the micro-light-emitting chip 4 when transferred to the detection substrate 1 is not likely to cause a single electrode 41 to cross over to the two lead-out portions 21 and cause a short circuit. When the bonding material between the micro-light-emitting chip 4 and the detection substrate 1 overflows, it is not likely to be directly short-circuited due to the larger insulation interval between the two lead-out portions 21.

[0062] S104, dividing the detection substrate into a plurality of test modules having a size larger than the micro light-emitting chip;

[0063] In this embodiment, a test module 11 includes a conductive unit 2 and a micro-light emitting chip 4 located on the conductive unit 2. The segmentation performed in step S104 refers to physically dividing the detection substrate 1 into a plurality of independent sub-substrates, each of which includes a conductive unit 2 and a micro-light emitting chip 4 disposed thereon. It is understandable that the size of the sub-substrate is larger than the size of a single micro-light emitting chip 4. In this embodiment, the micro-light emitting chip 4 that is difficult to operate as a single unit is formed into a larger and single independent test module 11 by segmenting the detection substrate 1 after mass transfer, which makes it easier to enter the subsequent detection process. In some embodiments, the detection of a single micro-light emitting chip 4 can be completed.

[0064] To facilitate subsequent detection steps, in some embodiments, for example Figure 5 As shown, the detection substrate 1 is divided into a quadrilateral test module 11 with a shortest side not less than 100um and a longest side not greater than 500um. Exemplarily, the test module 11 can be a quadrilateral with a width of 300um and a length of 500um as a whole, or it can also be formed as a quadrilateral with a width of 400um and a length of 450um. In other examples, the side length can also be, for example, 200um, 250um, 300um, etc. It can form more test modules 11 on the same detection substrate 1, and the size of each test module 11 can be easily operated individually, which avoids the situation in which a single micro-light-emitting chip 4 is too small to be detected individually in some implementation processes.

[0065] S105, performing performance testing on each test module one by one;

[0066] That is, the performance of the micro-light-emitting chip 4 in the test module 11 is tested, and the lead-out portion 21 in the test module 11 still retains an area exposed to the outside, and the electrical connection with the test circuit 51 can be achieved through the exposed area of ​​the lead-out portion 21 (that is, the bonding area). In the present application, the test module 11 can be tested one by one, so as to achieve the detection of a single micro-light-emitting chip 4.

[0067] In some embodiments, in order to improve the efficiency of performance testing and better compatibility with existing testing conditions, see Figure 6 As shown, the steps of performing performance testing on the test modules 11 one by one include:

[0068] S201, providing a test jig substrate, on which a test circuit is provided;

[0069] The test circuit 51 on the test fixture substrate 5 may also have a pad area 212 for electrical connection. The test circuit 51 on the test fixture substrate 5 is used to perform drive control on the micro light emitting chip 4 in response to meet the requirements of the corresponding test items.

[0070] S202, set the test module on the test jig substrate, and each lead-out portion is connected to the corresponding test circuit; the lead-out portion 21 and the test circuit 51 can be connected by means including but not limited to wire bonding, for example, wire bonding is performed between each lead-out portion 21 and the corresponding test circuit 51. In practical applications, the pad area 212 of the lead-out portion 21 can also be set on the other side of the detection substrate 1, and the connection can be achieved by mounting or other means. It should be understood that the overall size of the test module 11 is significantly larger than the micro-light-emitting chip 4 itself. Whether it is set on the test jig substrate 5 or in the process of wire bonding and other processes, the required operation requirements are lower than directly operating the micro-light-emitting chip 4 itself, and some implementation processes can be operated individually.

[0071] By forming the test module 11 and then cooperating with the test jig substrate 5, it is avoided to transfer the entire array of micro-light emitting chips 4 to the TFT backplane for testing, which reduces the process cycle and enables testing at a lower cost.

[0072] S203, driving the corresponding micro light-emitting chip through the test circuit to test it;

[0073] The test items include but are not limited to at least one of the photoelectric performance, luminous angle, and saturation current of a single Micro LED. At the same time, the photoelectric performance changes before and after the growth substrate 31 is peeled off can be compared, and the reliability of the micro light-emitting chip 4 can be verified. When testing, the test jig substrate can be sent to the corresponding test equipment to complete the test with the test equipment.

[0074] In some embodiments, see Figure 7 As shown, the step of performing performance testing on the test modules 11 one by one includes the step of providing a test jig substrate 5 including:

[0075] S301, providing at least two test fixture substrates corresponding to different test items, each of which is provided with a test circuit;

[0076] S302, respectively setting different test modules on the test jig substrates of different test items, and each lead-out portion is connected to a corresponding test circuit;

[0077] S303, driving corresponding micro light-emitting chips through test circuits on different test jig substrates to perform at least two different performance tests;

[0078] The test jig substrates 5 provided corresponding to different test items can be the same or different, and are configured according to the actual needs of different test equipment or test items. In the micro-luminescent chip testing method of this embodiment, the multiple test modules 11 divided from the detection substrate 1 can be divided into multiple groups, and each group of test modules 11 is respectively set on the test jig substrate 5 required for different test items, so as to achieve the purpose of testing different performances of the micro-luminescent chip 4. In some embodiments, parallel testing can be performed, and the test efficiency is high. It should be noted that the different test modules 11 provided in step S302 are not the same individually, but the test modules 11 in the test process can be the same in structure, and the micro-luminescent chip 4 set, etc. For example, they can be different test modules 11 divided from the same detection substrate 1.

[0079] In some embodiments, the conductive unit 2 of the detection substrate 1 may be a conductive metal disposed on the surface of the detection substrate 1. The conductive unit 2 has a large area, and more areas are still exposed after the micro light-emitting chip 4 is disposed.

[0080] In some embodiments, see Figure 8 As shown, the step of providing the detection substrate 1 includes:

[0081] S401, providing a substrate;

[0082] S402, providing a conductive metal layer on one side of the substrate;

[0083] S403, patterning the conductive metal layer to form a conductive unit;

[0084] The process of forming the conductive unit 2 on the detection substrate 1 is simple, and only requires the corresponding conductive metal to be arranged on the substrate. It is easy to manufacture and has low cost.

[0085] like Figure 5As shown, in one embodiment, the lead-out portion 21 includes a die-bonding region 211 directly connected to the electrode 41 of the micro-light-emitting chip 4, and a pad region 212 away from another lead-out portion 21, and the pad region 212 is larger than the die-bonding region 211. The die-bonding regions 211 of the two lead-out portions 21 are close to each other, and the interval between the die-bonding regions 211 is not less than the interval between the two electrodes 41 on the micro-light-emitting chip 4. The size of the die-bonding region 211 can be the same as or slightly larger than the size of the electrode 41 of the micro-light-emitting chip 4, and the pad region 212 can be respectively arranged on opposite sides to provide an electrically connectable area for subsequent test lighting. In some embodiments, the pad area 212 is a quadrilateral with the shortest side not less than 100um and the longest side not more than 300um, for example, the side length may be 150um, 200um, 250um, etc. In some embodiments, the pad area 212 may be a circle with a radius not less than 100um and not more than 300um, for example, the radius may be 150um, 200um, 250um, etc. Through the larger pad area 212, the small-sized chip below 100um is enlarged into a larger-sized test module 11. In some implementation processes, the pad area 212 can be electrically connected by traditional methods such as wire bonding, without the need to use a traditional TFT backplane to complete the driving of the micro-light-emitting chip 4 array, thereby achieving simpler and low-cost detection of a single micro-light-emitting chip 4. In some implementation processes, such as Figure 5 The lead-out portion 21 of the example is, after the micro-light-emitting chip 4 is arranged, the exposed bonding area is the pad area 212 .

[0086] In other embodiments, see Fig. 9 As shown, the conductive unit 2 can be arranged on both sides of the detection substrate 1, wherein the die-bonding area 211 is arranged on the first side, and the pad area 212 is arranged on the second side, and the die-bonding area 211 and the pad area 212 can be connected through a conductive through hole 22. The test module 11 formed in this way can be electrically connected to the test circuit 51 by mounting, without the need for wire bonding.

[0087] In order to better understand the micro-light emitting chip testing method of the present application, the following is an explanation of the specific micro-light emitting chip 4 manufacturing and testing process. In this example, the Micro LED chip is taken as an example. Fig.10 and Fig.11 The production process includes but is not limited to:

[0088] S501, providing a growth substrate, and growing an epitaxial layer on the growth substrate;

[0089] like Fig.11As shown in (a), an epitaxial layer is grown on one side of the growth substrate 31, and the epitaxial layer includes but is not limited to an N-type semiconductor layer 42, a P-type semiconductor layer 44, and an active layer 43 between the N-type semiconductor layer 42 and the P-type semiconductor layer 44. The material of the epitaxial layer mainly includes gallium nitride, but other semiconductor materials such as gallium arsenide may also be used in some implementation processes.

[0090] In this step, a mesa pattern is formed by photoetching on the epitaxial layer, so that the P-type semiconductor layer 44 and the active layer 43 in the epitaxial layer are partially removed, and the N-type semiconductor layer 42 is exposed. Taking gallium nitride as an example, the P-type semiconductor layer 44 and the active layer 43 can be etched by dry etching using BCl3Cl2 as an etching gas. The etching depth can be 1-2um. After the etching is completed, the residual photoresist is removed to obtain a mesa pattern.

[0091] S502, forming a transparent conductive layer;

[0092] like Fig.11 As shown in (b), a transparent conductive layer 45 is sputtered on the epitaxial layer, and the material of the transparent conductive layer 45 includes but is not limited to ITO (Indium Tin Oxide), and the thickness thereof can be 200-2000 Å. Exemplarily, a pattern is photoetched on the sputtered ITO material, and the ITO material is wet-etched and debonded to obtain the transparent conductive layer 45.

[0093] S503, forming a cutting path pattern;

[0094] like Fig.11 As shown in (c), after the transparent conductive layer 45 is manufactured, the epitaxial layer is etched to the growth substrate 31. The area etched to the growth substrate 31 is the cutting path, so that a plurality of independent epitaxial layer areas are divided on the epitaxial wafer, and each epitaxial layer area can be made into an independent micro-light-emitting chip 4. After the micro-light-emitting chip 4 is manufactured, the epitaxial wafer can be cut and split along the position of the cutting path, so that each micro-light-emitting chip 4 is separated into an independent individual. Exemplarily, the photoresist can be first exposed and developed to form a corresponding pattern of the photoresist, and then the cutting path is manufactured by dry etching process using the photoresist as a mask. When the main component of the epitaxial layer includes gallium nitride, the etching gas can include but is not limited to BCl3Cl2, and the etching depth is 4-8um. The cutting path pattern is obtained after degumming.

[0095] S504, forming a passivation layer;

[0096] like Fig.11As shown in (d), a passivation material is deposited and a passivation layer 46 is formed by photolithography. The passivation material can be removed by dry etching. The etching gas can include but is not limited to CF4O2Ar. After etching, the photoresist can be removed. Exemplarily, the passivation layer 46 can also be a DBR (Distributed Bragg Reflection) layer.

[0097] S505, forming electrodes;

[0098] like Fig.11 As shown in (e), the material of the electrode 41 is disposed on the surface of the passivation layer 46 by evaporation or the like, and the pattern of the electrode 41 is obtained by photolithography. The thickness of the electrode 41 can be 1-3 μm, and it is connected to the epitaxial layer through the through hole on the passivation layer 46. The wafer formed at this time can be cut to obtain a single micro light-emitting chip 4.

[0099] It is understandable that the micro-light emitting chip 4 in this embodiment can also be manufactured by steps including but not limited to the above-mentioned examples. This embodiment does not limit the manufacturing process of the micro-light emitting chip 4 and its specific structure.

[0100] See also Fig.12 After the micro-light emitting chip 4 is manufactured on the growth substrate 31, the micro-light emitting chip testing method performed includes but is not limited to:

[0101] S601, providing a detection substrate;

[0102] In this example, a plurality of conductive units 2 are formed on the detection substrate 1, and each conductive unit 2 matches the specifications of the micro-light-emitting chip 4 and is also arranged in an array on the detection substrate 1. A pair of lead-out portions 21 of the conductive unit 2 is composed of a die-bonding region 211 and a pad region 212, wherein the die-bonding regions 211 are close to each other and there is a gap slightly larger than the distance between the electrodes 41 of the micro-light-emitting chip 4, and the pad region 212 is located on the side of each die-bonding region 211 away from the other lead-out portion 21.

[0103] S602, placing the growth substrate and the detection substrate in relative contact;

[0104] like Fig.13As shown, in this example, the growth substrate 31 can be attached to the detection substrate 1; in some examples, the growth substrate 31 can also be set above the detection substrate 1 but not directly contacting the detection substrate 1. In this process, the electrode 41 of the micro-light-emitting chip 4 can be aligned with the conductive unit 2 on the detection substrate 1 by including but not limited to a CCD (charge coupled device) visual alignment system. When the growth substrate 31 is attached to the detection substrate 1, or when the micro-light-emitting chip 4 falls from the growth substrate 31 to the detection substrate 1, the electrode 41 of the micro-light-emitting chip 4 is in contact with the conductive unit 2.

[0105] S603, bonding the micro light emitting chip to the detection substrate;

[0106] The bonding method includes but is not limited to laser bonding. In this example, the micro-light emitting chips 4 completely correspond to the conductive units 2, and all the micro-light emitting chips 4 are bonded to the detection substrate 1. In practical applications, the arrangement of the micro-light emitting chips 4 can be more dense, and only a part of the micro-light emitting chips 4 corresponds to the conductive units 2, and these part of the micro-light emitting chips 4 can be selectively bonded.

[0107] S604, separating the growth substrate from the micro-light-emitting chip bonded to the detection substrate;

[0108] The growth substrate 31 and the micro-light emitting chip 4 may also be separated by methods including but not limited to laser lift-off. If only a portion of the micro-light emitting chip 4 is bonded to the conductive unit 2, the laser lift-off process is also performed selectively. Fig.14 The schematic diagram of the top view of the detection substrate 1 is shown, and a micro light-emitting chip 4 is arranged between the lead-out portions 21 of each conductive unit 2 .

[0109] S605, dividing the detection substrate into test modules;

[0110] The area corresponding to each conductive unit 2 is cut out separately to form a test module 11, which can be individually subjected to subsequent tests. Only a single micro-light-emitting chip 4 is arranged in the test module 11, so the performance of the single micro-light-emitting chip 4 can be measured.

[0111] S606, placing the test module on the test jig substrate;

[0112] like Fig.15As shown, the test module 11 is fixed on the test jig substrate 5 by wire bonding, and the pad area 212 of the conductive unit 2 is connected to the test circuit 51 (not fully shown in the figure) by a wire 52. The wire 52 can be, but is not limited to, a metal conductive wire such as a gold wire or an aluminum wire. According to the requirements of the test project, a single or multiple test modules 11 can be set on a test jig substrate 5. The test module 11 can be set on the test jig substrate 5 required for different test projects to achieve the purpose of testing different performances.

[0113] S607, driving the micro light-emitting chip through the test circuit of the test jig substrate to perform performance testing;

[0114] The present application also provides a test module, which includes a sub-substrate and a micro-light-emitting chip 4 divided from a test substrate 1; the sub-substrate is larger than the micro-light-emitting chip 4, and includes a conductive unit 2 thereon, and the conductive unit 2 includes a pair of insulated lead-out portions 21. The micro-light-emitting chip 4 is arranged on the conductive unit 2, and the electrodes 41 of the micro-light-emitting chip 4 are electrically connected to the pair of lead-out portions 21; each lead-out portion 21 has an exposed bonding area after the micro-light-emitting chip 4 is arranged, and the bonding area is used to electrically connect the test circuit with the micro-light-emitting chip 4 during the performance test process.

[0115] The micro-light emitting chip 4 can be set on the detection substrate 1 by mass transfer or other methods, and then divided to form the test module 11. It can be understood that the micro-light emitting chip 4 that is difficult to operate as a single unit is set on the sub-substrate to form a larger and single independent test module 11, which is easier to enter the subsequent detection process. The test module 11 of the present application can be used to complete the detection of a single micro-light emitting chip 4 set thereon in some implementation processes. It should be noted that the test module 11 can also refer to the content in the description of the aforementioned micro-light emitting chip test method, which will not be repeated here.

[0116] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A micro-light emitting chip testing method, characterized in that: include: Providing a chip substrate, on which a plurality of micro light-emitting chips are arranged; Providing a detection substrate, the detection substrate comprising a plurality of conductive units corresponding to the micro-light-emitting chip, each of the conductive units comprising a pair of insulated lead-out portions; Transferring the micro-light-emitting chips in bulk to the detection substrate, wherein each transferred micro-light-emitting chip is disposed on one of the conductive units, and the electrodes of the micro-light-emitting chips are electrically connected to a pair of the lead-out portions, and each of the lead-out portions has an exposed bonding area after the transfer of the micro-light-emitting chips; Dividing the detection substrate into a plurality of test modules having a size larger than the micro-light-emitting chip, each of the test modules comprising a conductive unit and the micro-light-emitting chip located on the conductive unit; The test modules are subjected to performance testing one by one. During the performance testing process, the test circuit is electrically connected to the micro light-emitting chip through the bonding area.

2. The micro-light emitting chip testing method according to claim 1, characterized in that: The step of providing a detection substrate comprises: providing a substrate; Disposing a conductive metal layer on one side of the substrate; The conductive metal layer is patterned to form the conductive unit.

3. The micro-light emitting chip testing method according to claim 1, characterized in that: The step of performing performance testing on the test modules one by one comprises: Providing a test jig substrate, on which a test circuit is provided; The test module is arranged on the test fixture substrate, and each of the lead-out portions is connected to the test circuit accordingly; The corresponding micro light-emitting chip is driven by the test circuit to perform performance testing on it.

4. The micro-light emitting chip testing method according to claim 1, characterized in that: The step of performing performance testing on the test modules one by one comprises: Providing at least two test jig substrates corresponding to different test items, each of which is provided with a test circuit; The different test modules are respectively arranged on the test jig substrate of different test items, and each of the lead-out parts is correspondingly connected to the test circuit; The corresponding micro light-emitting chips are driven by the test circuits on different test jig substrates to perform at least two different performance tests.

5. The micro-light emitting chip testing method according to claim 3 or 4, characterized in that: The step of arranging the test module on the test fixture substrate comprises: Wire bonding is performed between each lead-out portion and the corresponding test circuit.

6. The micro-light emitting chip testing method according to claim 1, characterized in that: The test module is a quadrilateral with a shortest side not less than 100um and a longest side not greater than 500um.

7. The micro-light emitting chip testing method according to claim 1, characterized in that: The area of ​​the bonding region exposed by each of the lead-out portions after the micro-light-emitting chip is transferred is not less than the area of ​​each electrode of the micro-light-emitting chip.

8. The micro-light emitting chip testing method according to claim 7, characterized in that: Each of the lead-out portions includes a die-bonding region directly connected to the electrode of the micro-light-emitting chip, and a pad region connected to the die-bonding region, the pad region is larger than the die-bonding region, and the pad region is any one of the following: A quadrilateral with the shortest side not less than 100um and the longest side not more than 300um; A circle with a radius not less than 100um and not more than 300um.

9. The micro-light emitting chip testing method according to any one of claims 6 to 8, characterized in that: In each pair of the lead-out portions, the interval between the two lead-out portions is greater than the interval between the two electrodes on the micro light-emitting chip.

10. A test module, characterized in that: include: A sub-base formed by dividing the detection base plate, the sub-base plate comprising a conductive unit, the conductive unit comprising a pair of insulated lead-out portions; A micro-light-emitting chip is arranged on the conductive unit, and the size of the sub-substrate is larger than that of the micro-light-emitting chip; the electrodes of the micro-light-emitting chip are electrically connected to a pair of the lead-out parts, and each of the lead-out parts has an exposed bonding area after the micro-light-emitting chip is arranged, and the bonding area is used to electrically connect the test circuit with the micro-light-emitting chip during the performance detection process.

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