CN114975712A - Miniature LED chip quality detection structure and detection method thereof - Google Patents
Miniature LED chip quality detection structure and detection method thereof Download PDFInfo
- Publication number
- CN114975712A CN114975712A CN202210402200.4A CN202210402200A CN114975712A CN 114975712 A CN114975712 A CN 114975712A CN 202210402200 A CN202210402200 A CN 202210402200A CN 114975712 A CN114975712 A CN 114975712A
- Authority
- CN
- China
- Prior art keywords
- layer
- detection
- gallium nitride
- led chip
- groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
- H01L33/38—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes with a particular shape
- H01L33/382—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes with a particular shape the electrode extending partially in or entirely through the semiconductor body
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
- G01R31/2607—Circuits therefor
- G01R31/2632—Circuits therefor for testing diodes
- G01R31/2635—Testing light-emitting diodes, laser diodes or photodiodes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/2851—Testing of integrated circuits [IC]
- G01R31/2894—Aspects of quality control [QC]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/30—Structural arrangements specially adapted for testing or measuring during manufacture or treatment, or specially adapted for reliability measurements
- H01L22/32—Additional lead-in metallisation on a device or substrate, e.g. additional pads or pad portions, lines in the scribe line, sacrificed conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
- H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/58—Optical field-shaping elements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0016—Processes relating to electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0025—Processes relating to coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
- H01L2933/0058—Processes relating to semiconductor body packages relating to optical field-shaping elements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
- H01L2933/0066—Processes relating to semiconductor body packages relating to arrangements for conducting electric current to or from the semiconductor body
Abstract
The invention discloses a micro LED chip quality detection structure and a detection method thereof, wherein a first groove (6) and a second groove (7) which are formed by concave pits and extend into an N-type gallium nitride layer (2) are formed on the surface of a P-type gallium nitride layer (5) of the micro LED chip quality detection structure, a first bulge (8) is arranged on the periphery of the first groove (6), a plurality of second bulges (9) are arranged on the inner ring of the first groove (6), and an N electrode layer (13) on the first bulge (8) and a P electrode layer (14) on the second bulge (9) have the same horizontal height; the N electrode layers (13) are connected together, and the P electrode layer (14) has a detection layer (17) thereon. The invention firstly prepares the N-pole-shared micro LED chip, then arranges the detection layer (17) on the surface of the P pole, and only needs to contact the probe with the N pole and the detection layer (17) during detection, thereby lightening all qualified LED chips. After detection, the detection layer (17) is removed by using a washing aluminum liquid pickling method, so that the difficulty of LED detection is solved.
Description
Technical Field
The invention belongs to the technical field of micro LEDs, and particularly relates to a micro LED chip quality detection structure and a detection method thereof.
Background
The Micro LED display technology is a display technology which takes self-luminous micrometer-scale LEDs as light-emitting pixel units and assembles the light-emitting pixel units on a driving panel to form a high-density LED array. Due to the characteristics of small size, high integration level, self-luminescence and the like of the micro LED chip, compared with an LCD and an OLED, the micro LED chip has the advantages of higher brightness, resolution, contrast, energy consumption, service life, response speed, thermal stability and the like in the aspect of display.
Micro LED applications will extend from flat panel displays to a number of areas such as AR/VR/MR, spatial displays, flexible transparent displays, wearable/implantable optoelectronic devices, optical communication/optical interconnects, medical detection, smart car lights, etc. It is expected that by 2025 Micro-LED technology based products such as high end televisions, cell phones, watches, etc. will come to market with market value exceeding 28 billion dollars. By 2035 years, China realizes a display module of a Micro-LED-based ultra-large scale integrated light-emitting unit and realizes a Micro-LED highly integrated system in illumination, space three-dimensional display, space positioning and information communication.
The Micro LED has great application prospect in the future, but the current problem of manufacturing cost of the Micro LED seriously affects the commercialization process of the Micro LED, the reason is that the bottleneck of a huge transfer technology is still broken through, the traditional huge transfer is single transfer single eutectic welding, the single transfer severely limits the mass production process of the Micro LED, as the resolution ratio of the Micro LED is higher, a very small Micro LED display screen contains a large number of LED wafers, such as a Micro LED display screen with about 0.39 inch, the number of the contained LED wafers is about 240 ten thousand, if a single transfer method is adopted, the time and labor are particularly consumed, the implementation is difficult, the single eutectic welding can greatly reduce the product qualification rate, the reason is that after one LED wafer is transferred, the control substrate is welded with the control substrate by heating, and after the next LED wafer is transferred, the control substrate is heated integrally, the second LED chip and the control substrate are welded together, and the welding point of the first LED chip is melted when the control substrate is heated integrally. The problem of secondary multiple melting occurs, the LED wafer is damaged, and the product percent of pass is seriously influenced.
More specifically, in the prior art, because the eutectic is heated on the circuit board side in a manner that one LED is placed on the control substrate, the heating is repeated once each time the eutectic is placed, the repeated heating damages the eutectic LED die and makes it difficult to realize the mass transfer of the LEDs. The invention adopts laser eutectic welding, which is an eutectic method that a whole LED array is welded on a control substrate in an alignment way at one time, and then a sapphire substrate is removed. The invention aligns and attaches the micro LED chip with a plurality of LED wafers and the control substrate together; and heating the butt welding point by using the laser eutectic welding system and completing welding. The secondary melting of the single transfer eutectic welding point of the single Micro LED can be effectively avoided, and the Micro LED is damaged.
However, the P-pole (positive pole) in the micro LED chip is located on top of the LED light-emitting layer, and the initial position of the P-pole (positive pole) is thicker than the N-pole (negative pole) by the thickness of the LED light-emitting layer, so that the P-pole (positive pole) in the micro LED chip and the positive pole of the control substrate are just in contact during eutectic crystal formation, and the N-pole (negative pole) in the micro LED chip and the negative pole of the control substrate cannot be in contact due to the small thickness of the LED light-emitting layer, because the problem cannot achieve the eutectic crystal effect. In order to solve the problem, if the N pole and the P pole of the micro LED chip are in the same height plane, the thickness of the N pole is larger than that of the P pole by one LED light emitting layer, which may cause the P pole to be melted and the N pole to be too thick and not to be melted during laser eutectic welding, and may cause damage to the LED chip due to too long heating time for ensuring the melting of the N pole, so that the two electrodes cannot be in contact with the positive pole and the negative pole of the control substrate at the same time, and the thicknesses of the two electrodes are the same, so that the eutectic can be melted and completed at the same time.
In addition, gaps are formed between the light emitting points of the prior micro LED chip, when eutectic crystals are heated by laser, the gaps are formed on two sides of the LED light emitting points by pressurizing, so that the LED light emitting points are not supported, the LED is deformed or even collapsed, the different LED light emitting points are one of different three primary colors when emitting light, and the gaps between the two LED light emitting points can influence each other to cause light mixing and influence the display effect.
One of the more critical issues is: because a very small Micro LED display screen contains a large number of LED wafers, for example, a Micro LED display screen of about 0.39 inches, wherein the number of the contained LED wafers is about 240 tens of thousands, the detection of the LED quality is also difficult, an independent luminous point is arranged below each anode of the LED chip, when the LED is inspected separately, if a single probe needle corresponds to each anode, the detection of electric quantity LED luminous points is not practical, because the number of the LED luminous points is too large, in addition, the detection is carried out by a hard detection platform, because the flatness and error problems can cause that the LED anode cannot contact with the detection platform, the detection of each luminous point cannot be accurately realized, and in addition, even if part of the luminous points are not lighted, the problem of the luminous points is not determined or is not flat, and the problem that the anode of the luminous point does not contact with the probe needle is not caused.
The present invention has been made to solve the above problems.
Disclosure of Invention
The invention aims to solve the problem that the anode and the cathode are not on the same plane when Micro LED is eutectic, and because the LED structure adopts a common-cathode structure, an LED cathode film layer and an LED anode film layer are not on the same plane, the eutectic point of the metal of the cathode and the anode is not on the same plane, and the eutectic effect can not be achieved due to the problem during eutectic. In addition, gaps between the LEDs are not filled, the formed gaps are not supported on two sides of the pressurized LEDs due to heating of laser during eutectic, the LEDs are deformed and even collapsed, and when the LEDs re-emit light, the LEDs can mutually influence to cause light mixing and influence the display effect. Therefore, the LED cathode is LED to the position on the same plane as the anode, the gap between the LED luminous point and the LED luminous point is filled with the infrared-resistant material, the material can form a retaining wall between the LEDs, the LEDs are prevented from being deformed and even collapsed due to heating during eutectic crystal, and light of the LED luminous points on two sides is prevented from being mixed.
In order to solve the difficulty of LED detection, the method comprises the steps of connecting a plurality of N electrode layers 13 together, connecting a plurality of P electrode layers 14 together, only arranging different numbers of detection probes on the positive electrode and the negative electrode of an LED according to the size of a module during detection, and electrifying the positive electrode and the negative electrode of the LED so as to light all qualified LED chips. After the detection is finished, the anode of each LED is separated through an etching process, but in the implementation process, it is very difficult to separate the P electrode layers 14 which are connected together, and since the gap between the adjacent P electrodes is very small, when the gap between the two P electrode layers is broken, the P electrodes on the two sides of the gap are affected, so that the quality condition of each LED light-emitting point is judged after the detection is finished, but the P electrodes are damaged in the separation process of the P electrode layers 14 which are connected together, and the condition that the LED light-emitting point is not lighted appears again, that is, the LED light-emitting point is qualified in quality inspection, but the LED light-emitting point is not lighted on the actually used LED chip.
In order to further solve the difficulty of LED detection, the invention firstly prepares a micro LED chip, then arranges the detection layer 17 on the surface of the P electrode layer 14, only needs to arrange different numbers of detection probes on the LED detection layer 17 according to the size of the module during detection, and then energizes the detection layer 17, thereby lightening all qualified LED chips. After the detection is finished, the detection layer 17 is removed by a method of aluminum washing liquid pickling, so that the difficulty of LED detection is solved. Further, the method for forming the detection layer 17 is plating by using PVD equipment, and the method for removing the detection layer is aluminum metal layer removal by aluminum washing liquid pickling, namely, the formation and removal of the detection layer 17 are very simple, the N electrode layer 13 and the P electrode layer 14 at the lower layer cannot be damaged, the qualified quality inspection result in detection is ensured, and the actually used LED chip is qualified.
The invention provides a micro LED chip quality detection structure which is a common cathode-common anode structure and comprises a substrate 1, a U-shaped gallium nitride layer 2, an N-shaped gallium nitride layer 3, a light emitting layer 4 and a P-shaped gallium nitride layer 5, wherein the U-shaped gallium nitride layer 2, the N-shaped gallium nitride layer 3, the light emitting layer 4 and the P-shaped gallium nitride layer 5 sequentially extend outwards from one side of the substrate 1;
the surface of the P-type gallium nitride layer 5 is provided with a first groove 6 and a second groove 7 which are formed in a concave mode and penetrate into the N-type gallium nitride layer 2,
a first bulge 8 is arranged on the periphery of the first groove 6, a plurality of second bulges 9 are arranged on the inner ring of the first groove 6, and the second bulges 9 are spaced by second grooves 7;
the P-type gallium nitride layer 5 is provided with an insulating layer 10, the insulating layer 10 is provided with a first opening 11 at the first groove 6, and the insulating layer 10 is provided with a second opening 12 at the second protrusion 9;
the first opening 11 is provided with an N electrode layer 13 which is in contact with the N-type gallium nitride layer 2 and extends from the first opening 11 to the first protrusion 8; the second opening 12 is provided with a P electrode layer 14 which is in contact with the P-type gallium nitride layer 2;
the N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same level;
the N electrode layers 13 are connected together and the P electrode layer 14 has a detection layer 17 thereon.
The N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same level. The cathode is LED out to be in the same plane structure with the anode, and the anode and the cathode of the Micro LED cannot be welded together at the same time in eutectic due to the fact that the anode and the cathode of the Micro LED are not in the same coating. The method adopted before solving the problem is to plate two layers of metal conductive materials on the lower negative electrode, so that the positive electrode and the negative electrode are theoretically on the same plane, and the defects of thick and uneven plating layer, easy generation of phenomena of welding leakage and excessive and overheated concentrated current of welding contact points, and metal overflow after excessive heating of solder during eutectic process are overcome. Therefore, the LED structure is improved, other film layers at the cathode of the Micro LED are reserved in the processing process, and then a layer of metal is plated to serve as a lead to lead the cathode out of a groove between the cathode and the LED to the reserved cathode grinding layer. From the bottom to the same plane as the anode. Therefore, the anode and the cathode can be ensured to be on the same plane to the maximum extent. The eutectic quality can be improved qualitatively.
Preferably, the P-type gallium nitride layer 5 is further provided with a flat conductive layer 15;
the surface of the flat conductive layer 15 is provided with a first groove 6 and a second groove 7 which are formed in a concave mode and penetrate into the N-type gallium nitride layer 2,
a first bulge 8 is arranged on the periphery of the first groove 6, a plurality of second bulges 9 are arranged on the inner ring of the first groove 6, and the second bulges 9 are spaced by second grooves 7;
the flat conductive layer 15 has an insulating layer 10 thereon, the insulating layer 10 has a first opening 11 at the first groove 6, and the insulating layer 10 has a second opening 12 at the second protrusion 9;
the first opening 11 is provided with an N electrode layer 13 which is in contact with the N-type gallium nitride layer 2 and extends from the first opening 11 to the first protrusion 8; the second opening 12 is provided with a P electrode layer 14 which is in contact with the flat conductive layer 15;
the N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same level.
The side away from the substrate 1 is "up" in the direction in the present invention.
Preferably, the material of the flat conductive layer 15 is an ITO material. The flat conductive layer 15 has the function that the light emitting layer 4 has poor light emitting effect due to uneven and uneven surface of the P-type gallium nitride layer 5, and the flat conductive layer 15 has the function of flattening the P-type gallium nitride layer 5 and having a conductive function so as to connect the P-electrode layer 14 to the P-type gallium nitride layer 2.
Preferably, the detection layer 17 is a conductive metal layer selected from metallic aluminum materials.
Preferably, there is one first groove 7 and a plurality of second grooves 8; the number of the first projections 8 is one, and the number of the second projections 9 is plural.
Preferably, the second groove 8 also contains a light-barrier 16 therein.
Preferably, the material of the light-shielding body 16 is a material that does not absorb infrared light, and is selected from but not limited to photoresist, which is a material commonly used in the art, and is a high molecular polymer derived from Biphenyl cyclobutene.
The light separator 16 functions in three ways: 1. the light condensing function prevents the light generated by the light emitting layer 4 from being dissipated into the second groove 7; 2. the light generated by the light-emitting layer 4 is the three primary colors of red, green and blue as required, and the light-isolating body 16 can avoid the problem of blending of the light with different colors at two sides; 3. since the material of the light-shielding body 16 is a material that does not absorb infrared light, and it is the infrared laser eutectic soldering that is used when the micro LED chip and the control substrate are eutectic, reference may be made to the application numbers that the applicant has filed: 2021106926206, the name is: a device and a method for laser eutectic welding of a micro LED chip and a control substrate are disclosed. The material of the light-isolating body 16 is a material which does not absorb infrared light, so that the light-isolating body is not heated and melted in the infrared laser eutectic welding process, and the structural stability of the micro LED chip is never ensured.
Preferably, the substrate 1 is selected from sapphire materials, which are also the less expensive substrate materials conventionally used in the art; the N electrode layer 13 and the P electrode layer 14 are made of Ti (titanium), Ni (nickel) and gold tin AuSn; the dimensions of the first opening 11 and the second opening 12 are also critical, and are determined according to the plated area and the magnitude of the current transmitted by the LED power consumption, and the second opening, i.e. the P-electrode opening, is relatively small, because too large an opening would result in a small influence on the flat surface of the plated metal layer on the subsequent eutectic.
The second aspect of the present invention provides a method for detecting the quality of a micro LED chip according to the first aspect of the present invention, which comprises the steps of preparing a micro LED chip, and then disposing a detection layer 17 on the surface of the micro LED chip:
1. taking the substrate 1, and sequentially extending a U-shaped gallium nitride layer 2, an N-shaped gallium nitride layer 3, a light emitting layer 4 and a P-shaped gallium nitride layer 5 on the surface of the substrate;
2. the surface of the P-type gallium nitride layer 5 is provided with a first groove 6 and a second groove 7 which are formed in a concave mode and penetrate into the N-type gallium nitride layer 2;
3. forming an insulating layer 10 on the P-type gallium nitride layer 5;
4. a first opening 11 is formed in the insulating layer 10 at the first groove 6, and a second opening 12 is formed in the second protrusion 9;
5. forming an N electrode layer 13 and a P electrode layer 14;
6. the detection is realized by plating a layer of aluminum metal film on the P electrode by using PVD equipment, so that the detection layer 17 which connects the P electrode layer 14 together is formed on the surface of the P electrode layer 14, and a probe of a detection device is directly contacted with the connected N electrode layer 13 and the detection layer 17.
Preferably, the detection layer 17 on the surface of the quality detection structure of the micro LED chip after quality detection is removed by using an aluminum washing liquid pickling method, and the detection layer is taken as eutectic crystal of the micro LED chip and the control substrate; the control substrate comprises a control substrate main body, and a control substrate negative electrode and a plurality of control substrate positive electrodes which are positioned on the control substrate main body; and aligning the N electrode layer 13 with the negative electrode of the control substrate, aligning the P electrode layer 14 with the positive electrode of the control substrate, and then eutectic-welding the micro LED chip and the control substrate together by laser.
The structure of the control substrate can refer to the patent with application number 2021109313035 filed by the applicant, which is named as a eutectic structure of a micro LED chip and a control substrate and a preparation method thereof. Likewise, the expression control substrate in this patent is equally applicable to the present invention. The eutectic welding device can refer to the application numbers which are already applied by the applicant: 2021106926206, the name is: a device and a method for laser eutectic welding of a micro LED chip and a control substrate are disclosed. Likewise, the expression eutectic bonding device in this patent is equally applicable to the present invention.
In conclusion, the key points of the invention are as follows:
key point 1: BM glue is filled between the LED luminous points, and light emitted by the LED can be reflected to achieve the purpose of condensing light and preventing astigmatism. Therefore, the mutual influence among the LED luminous points during the light emitting can be avoided, and the display picture quality of the screen is reduced. The BM glue is transparent material or photoetching material which can not absorb infrared light. One side absorbs laser infrared rays during laser eutectic, the filling material generates heat, melts and deforms, and the laser wavelength is near infrared light of 980 nm.
Key point 2: the cathode is LED out to be in the same plane structure with the anode, and the anode and the cathode of the Micro LED cannot be welded together at the same time in eutectic due to the fact that the anode and the cathode of the Micro LED are not in the same coating. The method adopted before solving the problem is to plate two layers of metal conductive materials on the lower negative electrode, so that the positive electrode and the negative electrode are theoretically on the same plane, and the defects of thick and uneven plating layer, easy generation of phenomena of welding leakage and excessive and overheated concentrated current of welding contact points, and metal overflow after excessive heating of solder during eutectic process are overcome. Therefore, the LED structure is improved, other film layers at the cathode of the Micro LED are reserved in the processing process, and then a layer of metal material is plated to serve as a lead to lead the cathode out of a groove between the cathode and the LED light-emitting point to the reserved cathode film layer. The eutectic powder is led to the same plane with the anode from the bottom, so that the anode and the cathode can be ensured to be on the same plane to the maximum extent, and the eutectic quality can be qualitatively improved.
The key point 3 is that a single LED is unrealistic to light when the LEDs are sorted, the number is too large, the detection is performed by a hard detection platform method before, and because the flatness and the error problem can cause that some LEDs cannot be contacted with the detection platform, the invention firstly prepares a micro LED chip, then arranges a detection layer 17 on the surface of a P electrode layer (14), only arranges different numbers of detection probes on the LED detection layer 17 according to the size of a module during detection, and then energizes the N electrode layer 13 and the detection layer 17 which are connected with each other, thereby lighting all qualified LED chips. After the detection is finished, the detection layer 17 is removed by a method of aluminum washing liquid pickling, so that the difficulty of LED detection is solved. Further, the method for forming the detection layer 17 is plating by PVD equipment, and the method for removing the detection layer is a method for pickling by using aluminum washing liquid, namely, the formation and removal of the detection layer 17 are very simple, the N electrode layer 13 and the P electrode layer 14 at the lower layer cannot be damaged, the qualified quality inspection result in detection is ensured, and the LED chip which is actually used is qualified.
Compared with the prior art, the invention has the following beneficial effects:
1. the N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same level. The cathode is LED out to be in the same plane structure with the anode, and the anode and the cathode of the Micro LED cannot be welded together at the same time in eutectic due to the fact that the anode and the cathode of the Micro LED are not in the same coating. The method adopted before solving the problem is to plate two layers of metal conductive materials on the lower negative electrode, so that the positive electrode and the negative electrode are theoretically on the same plane, and the defects of thick and uneven plating layer, easy generation of phenomena of welding leakage and excessive and overheated concentrated current of welding contact points, and metal overflow after excessive heating of solder during eutectic process are overcome. According to the invention, the LED structure is improved, other film layers at the cathode of the Micro LED are reserved in the processing process, and then a layer of metal is plated to be used as a lead, so that the cathode is LED out from a groove between the cathode and an LED light-emitting point to the reserved cathode grinding layer. The eutectic powder is led to the same plane with the anode from the bottom, so that the anode and the cathode can be ensured to be on the same plane to the maximum extent, and the eutectic quality can be qualitatively improved.
2. According to the invention, the micro LED chip is firstly prepared, then the detection layer 17 is arranged on the surface of the micro LED chip, when in detection, only different numbers of detection probes are required to be arranged on the LED detection layer 17 according to the size of the module, and then the N electrode layer 13 and the detection layer 17 which are connected are electrified, so that all qualified LED chips are lightened. After detection is finished, the detection layer 17 is removed by a method of washing aluminum liquid and pickling, so that the difficulty of LED detection is solved. Further, the method for forming the detection layer 17 is plating by PVD equipment, and the method for removing the detection layer is a method for pickling by using aluminum washing liquid, namely, the formation and removal of the detection layer 17 are very simple, the N electrode layer 13 and the P electrode layer 14 at the lower layer cannot be damaged, the qualified quality inspection result in detection is ensured, and the LED chip which is actually used is qualified.
3. In a preferred embodiment of the present invention, the P-type gallium nitride layer 5 further has a flat conductive layer 15 thereon, the flat conductive layer 15 is used for making the light emitting layer 4 have poor light emitting effect due to the uneven and uneven surface of the P-type gallium nitride layer 5, and the flat conductive layer 15 is used for flattening the P-type gallium nitride layer 5 and has a conductive function to connect the P-electrode layer 14 to the P-type gallium nitride layer 2.
4. In a preferred embodiment of the present invention, the second groove 8 further contains a light barrier 16 therein. The material of the light separator 16 is a material that does not absorb infrared light and is selected from photoresist. The light separator 16 functions in three ways: 1. the light condensing function prevents the light generated by the light emitting layer 4 from being dissipated into the second groove 7; 2. the light generated by the light-emitting layer 4 is the three primary colors of red, green and blue as required, and the light-isolating body 16 can avoid the problem of blending of the light with different colors at two sides; 3. the material of the light-isolating body 16 is a material which does not absorb infrared light, the material of the light-isolating body 16 is infrared laser eutectic welding when the micro LED chip and the control substrate are eutectic, and the material of the light-isolating body 16 is a material which does not absorb infrared light, so that the light-isolating body is not heated and melted in the infrared laser eutectic welding process, and the structural stability of the micro LED chip is never ensured.
Drawings
Fig. 1 is a schematic structural diagram of a quality detection structure of a micro LED chip.
Fig. 2 is a schematic structural diagram of a micro LED chip.
The names of the reference symbols are: the light-emitting diode comprises a substrate 1, a substrate 2, a U-shaped gallium nitride layer 3, an N-shaped gallium nitride layer 4, a light-emitting layer 5, a P-shaped gallium nitride layer 6, a first groove 7, a second groove 8, a first protrusion 9, a second protrusion 10, an insulating layer 11, a first opening 12, a second opening 12, an N-shaped electrode layer 13, a P-shaped electrode layer 14, a flat conducting layer 15, a light isolator 16 and a detection layer 17.
Detailed Description
The present invention will be described in further detail with reference to examples.
It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The materials or equipment used are not indicated by manufacturers, and all are conventional products available by purchase.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Further, "connected" as used herein may include wirelessly connected.
In the description of the present invention, "a plurality" means two or more unless otherwise specified. The terms "inner," "upper," "lower," and the like, refer to an orientation or a state relationship based on that shown in the drawings, which is for convenience in describing and simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "provided" are to be construed broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. To those of ordinary skill in the art, the specific meanings of the above terms in the present invention are understood according to specific situations.
It will be understood by those skilled in the art that, unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The electrode photoresist is photosensitive glue which is coated. The electrode photoresist is removed by soaking with the medicinal liquid and washing with clear water.
Example 1
Refer to fig. 1. The micro LED chip quality detection structure of the present embodiment is a common cathode, but the anode is a separate structure, and includes a substrate 1, and a U-shaped gallium nitride layer 2, an N-shaped gallium nitride layer 3, a light emitting layer 4, and a P-shaped gallium nitride layer 5 which extend outward from one side of the substrate 1 in sequence; the surface of the P-type gallium nitride layer 5 is provided with a first groove 6 and a second groove 7 which are formed in a concave manner and extend into the N-type gallium nitride layer 2, a first bulge 8 is arranged on the periphery of the first groove 6, a plurality of second bulges 9 are arranged on the inner ring of the first groove 6, and the second bulges 9 are spaced by the second grooves 7; the P-type gallium nitride layer 5 is provided with an insulating layer 10, the insulating layer 10 is provided with a first opening 11 at the first groove 6, and the insulating layer 10 is provided with a second opening 12 at the second protrusion 9; the first opening 11 is provided with an N electrode layer 13 which is in contact with the N-type gallium nitride layer 2 and extends from the first opening 11 to the first protrusion 8; the second opening 12 is provided with a P electrode layer 14 which is in contact with the P-type gallium nitride layer 2; the N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same horizontal height; the N electrode layers 13 on the first bumps 8 are connected together, and the P electrode layer 14 has a detection layer 17 thereon.
The P-type gallium nitride layer 5 is also provided with a flat conducting layer 15; the surface of the flat conducting layer 15 is provided with a first groove 6 and a second groove 7 which are formed in a concave manner and are deep into the N-type gallium nitride layer 2, a first bulge 8 is arranged on the periphery of the first groove 6, a plurality of second bulges 9 are arranged on the inner ring of the first groove 6, and the second bulges 9 are spaced by the second grooves 7; the flat conductive layer 15 has an insulating layer 10 thereon, the insulating layer 10 has a first opening 11 at the first groove 6, and the insulating layer 10 has a second opening 12 at the second protrusion 9; the first opening 11 is provided with an N electrode layer 13 which is in contact with the N-type gallium nitride layer 2 and extends from the first opening 11 to the first protrusion 8; the second opening 12 is provided with a P electrode layer 14 which is in contact with the flat conductive layer 15; the N electrode layer 13 on the first bump 8 and the P electrode layer 14 on the second bump 9 have the same level.
The side away from the substrate 1 in this embodiment is "up" in the direction.
The material of the flat conductive layer 15 is an ITO material. The number of the first grooves 7 is one, and the number of the second grooves 8 is multiple; one first projection 8 and a plurality of second projections 9 are formed.
The second groove 8 also contains a light-barrier 16. The material of the light separator 16 is a material that does not absorb infrared light and is selected from photoresist. The substrate 1 is selected from sapphire materials; the material of the N electrode layer 13 and the P electrode layer 14 is Ti (titanium) Ni (nickel) gold tin AuSn.
The specific preparation method of the micro LED chip comprises the following steps:
1. cleaning a material which is extended with a U-shaped gallium nitride layer 2, an N-shaped gallium nitride layer 3, a light-emitting layer 4 and a P-shaped gallium nitride layer 5;
2. plating a flat conductive layer 15ITO layer on the P-type gallium nitride layer 5;
3. applying a photoresist on the ITO layer;
4. exposing the photoresist by using an exposure and development method;
5. etching the ITO layer at the gap formed by exposure;
6. removing the photoresist;
7. continuing to apply the photoresist;
8. exposing the photoresist by using an exposure and development method;
9. etching the LED to form a first groove 6 and a second groove 7;
10. removing the photoresist;
11. plating of insulating layer 10, SiO 2 A layer;
12. defining the position of the opening, and continuing to apply the photoresist;
13. exposing light by using an exposure and development method;
14. etching SiO 2 A layer;
15. removing the photoresist;
16. filling photoresist in all the grooves to form the light isolator 16;
17. removing the photoresist in the first groove 6 and only keeping the photoresist in the second groove 7;
18. continuing to apply the photoresist;
19. exposing the photoresist by using an exposure and development method, forming a first opening 11 at the first groove 6, and forming a second opening 12 at the second protrusion 9;
20. plating an electrode layer at the opening to form an N electrode layer 13 and a P electrode layer 14;
21. forming a detection layer 17 on the surface of the P electrode layer 14 by using a PVD device;
22. and removing the photoresist to obtain the quality detection structure of the micro LED chip, as shown in figure 1.
23. And removing the detection layer 17 on the surface of the quality detection structure of the micro LED chip after the quality detection by using an aluminum washing liquid pickling method to obtain the micro LED chip, and the figure 2 shows that the quality of the micro LED chip is higher than that of the micro LED chip.
The micro LED chip of the present embodiment is eutectic with the control substrate.
The control substrate comprises a control substrate main body, and a control substrate negative electrode and a plurality of control substrate positive electrodes which are positioned on the control substrate main body;
and aligning the N electrode layer 13 with the negative electrode of the control substrate, aligning the P electrode layer 14 with the positive electrode of the control substrate, and then eutectic-welding the micro LED chip and the control substrate together by laser.
Claims (10)
1. A micro LED chip quality detection structure is characterized by being of a common cathode and common anode structure and comprising a substrate (1), and a U-shaped gallium nitride layer (2), an N-shaped gallium nitride layer (3), a light emitting layer (4) and a P-shaped gallium nitride layer (5) which extend outwards from one side of the substrate (1) in sequence;
the surface of the P-type gallium nitride layer (5) is provided with a first groove (6) and a second groove (7) which are formed in a concave manner and are deep into the N-type gallium nitride layer (2),
the periphery of the first groove (6) is provided with a first bulge (8), the inner ring of the first groove (6) is provided with a plurality of second bulges (9), and the second bulges (9) are spaced by a second groove (7);
the P-type gallium nitride layer (5) is provided with an insulating layer (10), the insulating layer (10) is provided with a first opening (11) at the first groove (6), and the insulating layer (10) is provided with a second opening (12) at the second protrusion (9);
the first opening (11) is provided with an N electrode layer (13) which is in contact with the N-type gallium nitride layer (2) and extends from the first opening (11) to the first protrusion (8); the second opening (12) is provided with a P electrode layer (14) which is in contact with the P type gallium nitride layer (2);
the N electrode layer (13) on the first bump (8) and the P electrode layer (14) on the second bump (9) have the same horizontal height;
the N electrode layers (13) are connected together, and the P electrode layer (14) is provided with a detection layer (17).
2. The micro LED chip quality detection structure according to claim 1, wherein said P-type gallium nitride layer (5) further has a flat conductive layer (15);
the surface of the flat conducting layer (15) is provided with a first groove (6) and a second groove (7) which are formed in a concave mode and penetrate into the N-type gallium nitride layer (2),
the periphery of the first groove (6) is provided with a first bulge (8), the inner ring of the first groove (6) is provided with a plurality of second bulges (9), and the second bulges (9) are spaced by a second groove (7);
the flat conductive layer (15) has an insulating layer (10) thereon, the insulating layer (10) has a first opening (11) at the first groove (6), the insulating layer (10) has a second opening (12) at the second protrusion (9);
the first opening (11) is provided with an N electrode layer (13) which is in contact with the N-type gallium nitride layer (2) and extends from the first opening (11) to the first protrusion (8); -at the second opening (12) a P-electrode layer (14) in contact with the flat conductive layer (15);
the N electrode layer (13) on the first bump (8) and the P electrode layer (14) on the second bump (9) have the same horizontal height.
3. The micro LED chip quality inspection structure according to claim 2, wherein the material of the flat conductive layer (15) is an ITO material.
4. The micro LED chip quality inspection structure according to claim 1, wherein the inspection layer (17) is a conductive metal layer selected from a metallic aluminum material.
5. The micro LED chip quality detection structure according to claim 1, wherein the number of the first grooves (7) is one, and the number of the second grooves (8) is plural; the number of the first protrusions (8) is one, and the number of the second protrusions (9) is plural.
6. The micro LED chip quality inspection structure according to claim 1, wherein the second recess (8) further contains a light isolator (16).
7. The micro LED chip quality inspection structure according to claim 1, wherein the material of the light separator (16) is a material that does not absorb infrared light, and is selected from a photoresist.
8. The micro LED chip quality inspection structure according to claim 1, wherein said substrate (1) is selected from sapphire materials; the N electrode layer (13) and the P electrode layer (14) are made of titanium, nickel or gold tin.
9. The method for detecting the quality of the micro LED chip as claimed in claims 1 to 8, wherein the micro LED chip is prepared and then the detection layer (17) is arranged on the surface of the micro LED chip, and the method comprises the following steps:
(1) taking the substrate (1), and sequentially extending a U-shaped gallium nitride layer (2), an N-shaped gallium nitride layer (3), a light-emitting layer (4) and a P-shaped gallium nitride layer (5) on the surface of the substrate;
(2) a first groove (6) and a second groove (7) which are formed in a concave mode and penetrate into the N-type gallium nitride layer (2) are formed in the surface of the P-type gallium nitride layer (5);
(3) forming an insulating layer (10) on the P-type gallium nitride layer (5);
(4) a first opening (11) is formed in the insulating layer (10) at the first groove (6), and a second opening (12) is formed in the second protrusion (9);
(5) forming an N electrode layer (13) and a P electrode layer (14);
(6) the detection is realized by plating an aluminum metal film on the P electrode to form a detection layer (17) which connects the P electrode layer (14) together on the surface of the P electrode layer (14) and directly contacting a probe of the detection device with the connected N electrode layer (13) and the detection layer (17).
10. The method for detecting the quality of the micro LED chip according to claim 9, wherein a detection layer (17) on the surface of the quality detection structure of the micro LED chip after quality detection is removed by a method of aluminum washing and pickling, and the detection layer is used as eutectic crystal of the micro LED chip and the control substrate;
the control substrate comprises a control substrate main body, and a control substrate negative electrode and a plurality of control substrate positive electrodes which are positioned on the control substrate main body;
and aligning the N electrode layer (13) with the negative electrode of the control substrate, aligning the P electrode layer (14) with the positive electrode of the control substrate, and then eutectic-welding the micro LED chip and the control substrate together by using laser.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210402200.4A CN114975712A (en) | 2022-04-18 | 2022-04-18 | Miniature LED chip quality detection structure and detection method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210402200.4A CN114975712A (en) | 2022-04-18 | 2022-04-18 | Miniature LED chip quality detection structure and detection method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114975712A true CN114975712A (en) | 2022-08-30 |
Family
ID=82978107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210402200.4A Withdrawn CN114975712A (en) | 2022-04-18 | 2022-04-18 | Miniature LED chip quality detection structure and detection method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114975712A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117080106A (en) * | 2023-09-21 | 2023-11-17 | 北京海炬电子科技有限公司 | Real-time co-location detection device for LED chip mass transfer and use method |
-
2022
- 2022-04-18 CN CN202210402200.4A patent/CN114975712A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117080106A (en) * | 2023-09-21 | 2023-11-17 | 北京海炬电子科技有限公司 | Real-time co-location detection device for LED chip mass transfer and use method |
| CN117080106B (en) * | 2023-09-21 | 2024-02-06 | 北京海炬电子科技有限公司 | Real-time co-location detection device for LED chip mass transfer and use method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10886257B2 (en) | Micro LED display device and method for manufacturing same | |
| TWI682436B (en) | Massive transferring method of micro leds and light-emitting panel module using the method | |
| TWI745206B (en) | Light emitting unit and display apparatus | |
| CN111725251B (en) | High-resolution full-color micro LED display | |
| US7683539B2 (en) | Light emitting device package and method for manufacturing the same | |
| EP3996139A1 (en) | Display device using micro led, and manufacturing method therefor | |
| US9119332B2 (en) | Method of mounting devices in substrate and device-mounting substrate structure thereof | |
| CN114175260A (en) | Method for manufacturing display device and substrate for manufacturing display device | |
| US20220367771A1 (en) | Display device using micro led, and manufacturing method therefor | |
| CN105304805A (en) | Light emitting device package | |
| CN106531867A (en) | Vertical structured chip having multiple color blocks independently emitting light and manufacturing method thereof | |
| CN109671764B (en) | Display device and forming method thereof | |
| KR20200106695A (en) | Led array package and manufacturing method thereof | |
| WO2011108664A1 (en) | Optical semiconductor device | |
| US20230068569A1 (en) | Method for soldering electronic component and method for manufacturing led display | |
| JP2002064112A (en) | Manufacturing method of photoelectron component | |
| CN114899298B (en) | Pixel unit and manufacturing method thereof, micro display screen and discrete device | |
| CN112652617A (en) | Preparation method of novel Micro-LED display device | |
| CN114975712A (en) | Miniature LED chip quality detection structure and detection method thereof | |
| CN110676368B (en) | Manufacturing method of detection device and detection method | |
| CN111525015B (en) | LED full-color display panel and packaging method thereof | |
| CN112117297A (en) | Full-color Micro LED array structure and preparation method thereof | |
| CN217086613U (en) | Miniature LED chip detects structure | |
| CN114373843A (en) | Micro LED chip detection structure and preparation method thereof | |
| CN216980600U (en) | Miniature LED chip and contain its eutectic structure |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20220830 |
|
| WW01 | Invention patent application withdrawn after publication |