Test methods and techniques for light-emitting devices

Abstract

The present invention provides a testing method and technique for light-emitting devices. The electrical and optical properties of light-emitting devices are measured using a probe card. According to one aspect of this disclosure, electroluminescence and photoluminescence testing of a light-emitting device is performed in the manufacturing process using a probe card. According to the embodiment of this disclosure, the probe card comprises millions of probe chips, which are simultaneously in close proximity to or in contact with the light-emitting device.

Description

Cross-reference of related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 515,773, “Test Method and Technique for Light-Emitting Devices,” filed on 26 July 2023. That application is incorporated herein by reference in its entirety. [Technical Field]

[0002] This disclosure relates in general to test methods and techniques for light-emitting devices. The electrical and optical responses of light-emitting devices are supplied and measured using probe cards. [Background technology]

[0003] As computing becomes increasingly integrated into daily life through smartphones, games, augmented reality (AR), and virtual reality (VR), the demand for smaller, higher-resolution, and more energy-efficient displays is constantly increasing. Since display components are typically the largest power consumers in mobile devices, there is significant pressure to reduce screen power consumption to extend battery life. To address this challenge, substantial investment and research have been made towards the development of micro-light-emitting diodes (micro-LEDs). Micro-LEDs are considered a next-generation display technology, offering higher resolution, superior color reproduction, high brightness, fast display refresh rates, and, most importantly, significantly improved energy efficiency. Micro-LEDs are a self-emissive display technology that operates at less than half the power consumption of conventional displays.

[0004] However, the introduction of new materials into the micro-LED manufacturing process, as well as yield issues arising from chip transfer and array-driver bonding, are hindering the commercialization of micro-LEDs. The human eye is highly sensitive and can detect a single defective micro-LED pixel in a display. Therefore, extensive optical and electrical testing of micro-LEDs is essential during the manufacturing and packaging processes. Unfortunately, the quality and functionality of existing probe cards and micro-scale testing technologies have not kept pace with the miniaturization of micro-LEDs, and the micro-LED industry is facing difficulties because systematic and random defects in the manufacturing process can persist across multiple lots, negatively impacting yield and time to market. [Overview of the project]

[0005] This disclosure generally relates to test methods and techniques for light-emitting devices. The electrical and optical properties of light-emitting devices are measured using probe cards.

[0006] According to one aspect of the present disclosure, a probe card is used to perform electroluminescence and photoluminescence testing of a light-emitting device in a manufacturing process. According to an embodiment of the present disclosure, the probe card comprises millions of probe chips that are positioned in close proximity to or in contact with the light-emitting device.

[0007] This disclosure provides early, actionable insights into which light-emitting devices are suitable for transitions, demonstrating the potential to reduce device design costs by 25%, double manufacturing iterations, and accelerate time to market by four months by identifying potential process variations. The testing paradigm enabled by this disclosure is amplified by strong trends driving mobility, connectivity, and enterprise, resulting in broad commercial and social impacts. This disclosure accelerates the development of light-emitting devices and advanced integrated circuits in 3nm, 1nm, and beyond fine processes where conventional testing methods are reaching their limits. Advances in this field impact a wide range of societal needs, including the continued miniaturization of electronic devices, the Internet of Things (IoT), mobile computing, virtual reality (VR), and augmented reality (AR).

[0008] The aspects of this disclosure can be used to test other light-emitting devices and many light-emitting elements, such as organic light-emitting diodes (OLEDs), light-emitting diodes (LEDs), microLEDs, vertical-cavity surface-emitting lasers (VCSELs), edge-emitting lasers (EELs), and nano-light-emitting diodes (nanoLEDs).

[0009] Generally, in some respects, a method for testing a light-emitting device is provided. This method includes at least two probes. Furthermore, it includes the step of applying a potential difference between a first probe and a second probe of the at least two probes. Furthermore, it includes the step of aligning the first probe and the second probe with the first and second terminals of the light-emitting device, respectively. Subsequently, it further includes commanding a movable stage to bring the first and second probes close to the first and second terminals of the light-emitting device. The speed or velocity of the moving stage generates a kinetic current within the light-emitting device. The generated kinetic current causes the light-emitting device to switch on, light up, emit light, or emit electromagnetic radiation. Switching off the light-emitting device is achieved by stopping the movement of the movable stage and / or increasing the isolation gap between one of the at least two probes and the first or second terminal of the light-emitting device.

[0010] In one example, the first and second terminals of the light-emitting device are located on the same side of the substrate of the light-emitting device.

[0011] In one example, at least a first terminal and at least a second terminal of the light-emitting device are located on the opposite side of the substrate of the light-emitting device.

[0012] For example, the first terminal is the anode and the second terminal is the cathode, or the first terminal is the cathode and the second terminal is the anode.

[0013] In one example, an image sensor generates an image of the light-emitting device while the light-emitting device wafer is scanned against one of at least two probes to which a bias is applied.

[0014] For example, the intensity or power of light emission or electromagnetic radiation changes in proportion to the kinetic current generated flowing through the light-emitting device.

[0015] For example, the amount of kinetic current changes in proportion to the movement speed of the movable stage.

[0016] For example, the amount of kinetic current changes in proportion to the potential difference applied between the first and second terminals of the light-emitting element.

[0017] For example, the amount of operating current is inversely proportional to the isolation gap between at least one of the two probes and either the first or second terminal of the light-emitting device.

[0018] For example, the amount of operating current is directly proportional to the area of ​​either the first or second terminal of the light-emitting element.

[0019] For example, the amount of kinetic current is directly proportional to the dielectric constant of the substance or gas present between the tip of at least one of the two probes and either the first or second terminal of the light-emitting device.

[0020] According to one example, the light emission or electromagnetic radiation is measured by a vision system.

[0021] According to one example, this vision system is capable of measuring radiation intensity, radiation output, radiation color, radiation luminance, radiation chromaticity, radiation peak wavelength, or radiation angle.

[0022] According to one example, the probe card includes a substrate and at least two probes made of a conductive material. One of the at least two probes has a probe tip including a memristor material or a polymer.

[0023] According to one example, the memristor material is configured to switch its state from a conductive state to an insulating state and vice versa.

[0024] According to one example, the memristor material is a deformable material configured to reversibly deform when pressed against a device under test.

[0025] According to one example, the memristor material includes metal oxides, chalcogenides, amorphous silicon, carbon, and polymer nanoparticles.

[0026] According to one example, the memristor material is a phase change material.

[0027] According to one example, the phase change material includes chalcogenide glass or germanium antimony telluride.

[0028] According to one example, the polymer is a deformable material configured to reversibly deform when pressed against a device under test. <0000!05>

[0029] According to one example, the polymer includes polydimethylsiloxane (PDMS) or an epoxy-based photoresist.

[0030] For example, an active or passive switch matrix is ​​integrated with the probe card.

[0031] In one example, at least one photon sensor is integrated into the probe card.

[0032] For example, a photon sensor is configured to measure and display emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, or emission angle.

[0033] Generally, a method for testing a light-emitting device is provided in a different respect. This method includes providing a probe card having at least one probe. This method further includes aligning a first probe of the at least one probe to a first terminal of the light-emitting device. Furthermore, the method includes applying a potential difference between the first probe and a second terminal of the light-emitting device. Furthermore, the method includes commanding a movable stage to bring the first probe closer to or into contact with the first terminal of the light-emitting device. The speed at which the movable stage moves generates a kinetic current within the light-emitting device. The generated kinetic current causes the light-emitting device to switch on, emit light, emit light, or emit electromagnetic radiation. Switching off the light-emitting device is achieved by stopping the movement of the movable stage and / or increasing the isolation gap between the first probe and the first and second terminals of the light-emitting device.

[0034] For example, the movement of the movable stage stops when the motion sensor detects that the tip of at least one probe is approaching or in contact with a first terminal of the light-emitting device.

[0035] For example, the motion sensor is integrated into the substrate of a probe card or light-emitting device wafer.

[0036] For example, motion sensors can be force sensors, capacitive sensors, proximity sensors, or light sensors.

[0037] Generally, a method for testing a light-emitting device is provided in a different respect. This method includes providing a probe card having at least two probes. The method further includes aligning a first probe of at least one probe to a first terminal of the light-emitting device and a second probe of at least two probes to a second terminal of the light-emitting device. Furthermore, the method includes applying a potential difference between the first probe and the second probe. Furthermore, the method includes commanding a movable stage to bring the first probe and the second probe into contact with the first and second terminals of the light-emitting device, respectively. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current is configured to switch on, light up, emit light, or emit electromagnetic radiation from the light-emitting device. When the first probe and the second probe establish contact with at least the first and at least the second terminals, respectively, a direct current flows within the light-emitting device. This direct current causes the light-emitting device to light up, emit light, or emit electromagnetic radiation. The light-emitting device is turned off by stopping the movement of the movable stage and increasing the isolation gap between at least one of the two probes and the first or second terminal of the light-emitting device.

[0038] Generally, from a different perspective, a method for testing a light-emitting device is provided. This method includes providing a probe card with at least one probe. This method further includes aligning a first probe with a first terminal of the light-emitting device. This method further includes forming a fixed isolation gap between the first probe and the first terminal of the light-emitting device. Furthermore, this method includes applying an AC or high-frequency signal to the first probe. The frequency of the AC or high-frequency signal is the resonant frequency of the light-emitting device. Furthermore, this method includes electrically grounding a second terminal of the light-emitting device. A resonant current is generated within the light-emitting device, thereby turning the light-emitting device on, causing it to emit light, emit light, or emit electromagnetic radiation.

[0039] In general, from another perspective, a method for testing a light-emitting device is provided. This method includes preparing a probe card with at least two probes. Furthermore, it includes aligning the first probe of the at least two probes with a first terminal of the light-emitting device and aligning the second probe of the at least two probes with a second terminal of the light-emitting device. Furthermore, it includes forming a fixed isolation gap between the first probe and the first terminal of the light-emitting device. Furthermore, the method includes applying an AC or high-frequency signal to the first probe while electrically grounding the second probe. The frequency of the AC or high-frequency signal is the resonant frequency of the light-emitting device. Furthermore, the method includes generating a resonant current within the light-emitting device, thereby switching on the light-emitting device, lighting it up, emitting light, or emitting electromagnetic radiation.

[0040] For example, the intensity or brightness of light emission or electromagnetic radiation is proportional to the amplitude or magnitude of the applied alternating current or high-frequency signal.

[0041] For example, high-frequency signals include radio frequency signals, microwave signals, infrared signals, or terahertz signals.

[0042] For example, a vision system is used to measure radiant intensity, radiant power, radiant color, radiant brightness, radiant chromaticity, radiant peak wavelength, or radiant angle.

[0043] For example, the image sensor is mounted on a probe card or the substrate of a light-emitting device.

[0044] For example, an image sensor is configured to measure radiant intensity, radiant power, radiant color, radiant brightness, radiant chromaticity, radiant peak wavelength, or radiant angle.

[0045] For example, an image sensor includes a material or device that is photon-sensitive to the emission wavelength of light or electromagnetic radiation emitted from a light-emitting device.

[0046] For example, the material or device is a diode or a field-effect transistor.

[0047] For example, an image sensor is an excitation source configured to excite a light-emitting device to emit light and / or electromagnetic radiation.

[0048] For example, the excitation source is a laser.

[0049] Generally, a method for testing a light-emitting device is provided in a different respect. This method includes providing a probe card having at least one probe. Furthermore, this method includes forming an isolation gap between a first probe of at least one probe tip and a first terminal of the light-emitting device. Furthermore, the method includes misaligning the first probe relative to a first terminal of the light-emitting device and applying a potential difference between the first probe and a second terminal of the light-emitting device. Furthermore, the method includes commanding a movable stage to laterally align the first probe relative to a first terminal of the light-emitting device. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current causes the light-emitting device to switch on, emit light, emit light, or emit electromagnetic radiation. Switching off the light-emitting device is achieved by stopping the lateral movement of the movable stage and / or causing a misalignment between the first probe and the first terminal of the light-emitting device.

[0050] Generally, another example provides a method for testing a light-emitting device. This method includes providing a probe card having at least two probes. This method includes forming an isolation gap between at least a first probe of the two probes and a first terminal of the light-emitting device. Furthermore, this method includes forming an isolation gap between a second probe of at least two probes and a second terminal of the light-emitting device. Furthermore, this method includes misaligning the first probe with respect to the first terminal of the photo-emitting device. Furthermore, this method includes misaligning the second probe with respect to the second terminal of the photo-emitting device. Furthermore, this method includes applying a potential difference between the first probe and the second probe. Furthermore, this method includes commanding a movable stage to align the first probe and the second probe laterally with respect to the first and second terminals of the photo-emitting device, respectively. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current turns on the light-emitting device, causing it to emit light, emit light, or emit electromagnetic radiation. The light-emitting device is turned off by stopping the lateral movement of the movable stage and / or by misaligning the first and second probes with respect to the first and second terminals of the light-emitting device.

[0051] In various embodiments, a processor or controller may be associated with one or more storage media (collectively referred to herein as “memory,” such as volatile and non-volatile computer memory, including RAM, PROM, EPROM, EEPROM, floppy disks, compact disks, optical disks, magnetic tapes, and SSDs). In some embodiments, the storage media may contain one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein. The various storage media may be fixed within the processor or controller or portable, and one or more programs stored thereon can be loaded onto the processor or controller to implement the various aspects discussed herein. The terms “program” or “computer program” are used herein in a general sense to refer to any type of computer code (e.g., software or microcode) that can be used to program one or more processors or controllers.

[0052] It should be understood that any combination of the aforementioned concepts and additional concepts discussed in more detail below (as long as these concepts do not contradict each other) is assumed to be part of the inventive subject matter disclosed herein. In particular, any combination of the claims listed at the end of this specification is assumed to constitute part of the inventive subject matter disclosed herein. It should also be understood that any term used explicitly herein and that may appear in any disclosure incorporated by reference should be given the meaning most consistent with the specific concepts disclosed herein.

[0053] These points and other aspects of various embodiments will become clear and be explained by referring to the embodiments described later. [Brief explanation of the drawing]

[0054] By reading the following detailed description in conjunction with the attached drawings, the present invention can be more fully understood and appreciated. [Figure 1A] Figure 1A is a side view of a probe card according to an embodiment of the present disclosure. [Figure 1B] Figure 1B is a side view of a light-emitting device wafer according to an embodiment of the present disclosure. [Figure 1C] Figure 1C is a side view of a probe card and a light-emitting device wafer in close proximity according to an embodiment of the present disclosure. [Figure 1D] Figure 1D shows an electrically equivalent circuit according to an embodiment of the present disclosure. [Figure 1E] Figure 1E is a plot of stage displacement, separation gap, and kinetic current against time, based on an aspect of this disclosure. [Figure 1F] Figure 1F is a side view of a probe card that mechanically contacts a light-emitting device wafer according to an aspect of this disclosure. [Figure 1G] Figure 1G is an electrically equivalent circuit according to an embodiment of the present disclosure. [Figure 1H] Figure 1H is a plot of stage displacement, separation gap, and kinetic current against time, according to an aspect of this disclosure. [Figure 1I] Figure 1I is a plan view of a light-emitting device wafer according to an embodiment of the present disclosure. [Figure 1J] Figure 1J is a plan view of a probe card according to an embodiment of the present disclosure. [Figure 1K] Figure 1K is a bottom view of a probe card according to an embodiment of the present disclosure. [Figure 1L] Figure 1L is a plan view of a probe card according to an embodiment of the present disclosure. [Figure 2A] Figure 2A is a plan view of a carrier according to an embodiment of the present disclosure. [Figure 2B] Figure 2B is a bottom view of a carrier according to an embodiment of this disclosure. [Figure 3A] Figure 3A is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 3B]Figure 3B is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 4] Figure 4 is a side view of an imager according to an embodiment of the present disclosure. [Figure 5A] Figure 5A is a side view of an imager arranged on a probe card according to an embodiment of the present disclosure. [Figure 5B] Figure 5B is a side view of an imager positioned below a light-emitting device wafer according to an embodiment of the present disclosure. [Figure 6] Figure 6 is a side view of a probe card in which a photosensitive device and an emissive device wafer are integrated together, according to an aspect of this disclosure. [Figure 7A] Figure 7A is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 7B] Figure 7B shows an electrically equivalent circuit according to an embodiment of the present disclosure. [Figure 7C] Figure 7C shows an electrically equivalent circuit according to an embodiment of the present disclosure. [Figure 8] Figure 8 is a side view of an imager arranged on a probe card according to an embodiment of the present disclosure. [Figure 9] Figure 9 is a side view of a probe card integrating a photosensitive device and an emissive device wafer according to an embodiment of the present disclosure. [Figure 10] Figure 10 is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 11A] Figure 11A is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 11B] Figure 11B is a side view of a probe card positioned in close proximity to a light-emitting device wafer, according to an embodiment of the present disclosure. [Figure 12] Figure 12 is a schematic diagram of a probe card mounted on an LED wafer. [Modes for carrying out the invention]

[0055] This disclosure describes various methods and techniques for testing light-emitting devices (LEDs) and for measuring their luminous intensity or output, luminous color, luminous brightness, luminous chromaticity, luminous peak wavelength, and luminous angle.

[0056] The ability to test millions of light-emitting devices in parallel enables light-emitting device manufacturers to gain actionable insights into performance early on, improve measurement throughput, reduce testing costs, and accelerate the commercialization of new display technologies.

[0057] Figure 1A shows a side view of the probe card 100A. The probe card substrate 102 can be made of a material that is optically transparent to the emission wavelength of the light-emitting device (LED). Therefore, electromagnetic waves emitted from the light-emitting device should be able to pass through the substrate 102. An imaging sensor can be placed on top of the probe card 100A to detect the transmitted electromagnetic radiation and convert it into an image. The substrate 102 can be made of an opaque or transparent material. If the probe card 100A is used to test a light-emitting device, it is preferable that the substrate 102 be transparent. Examples of transparent substrates include glass, Pyrex®, and fused silica. In the case of an LED that emits light at infrared wavelengths, the substrate 102 can be silicon. The first probe 104 and the second probe 106 are attached to the probe card substrate 102. The material that forms the probe tip 108 is attached to the tips of probes 104 and 106. Thus, this material is considered to form the probe tip on the first probe 104 and the second probe 106. The material may be a polymer and / or dielectric and / or memlist material. Polymers minimize damage to the probe tip and scratching of the LED during probing. Polymers may be conductive or insulating. Polymers may also be reversibly deformable. Examples of polymers include polydimethylsiloxane (PDMS), epoxy photoresists such as SU-8, common photoresists, and porous polymers. Probes 104 and 106 are electrically insulated from each other. The size and spacing of the probe tips range from nanometers to millimeters.

[0058] Continuing to refer to Figure 1A, this material could be a memlist. A memlist is a non-volatile electronic memory device whose resistance is programmable (resistor function) and subsequently retained (memory function). Therefore, a memlist can be programmed to be conductive or insulating (non-conductive). This memlist material could be a polymer with reversible deformation properties, which means it deforms reversibly when pressed against the device under test. Examples of memlist materials include metal oxides, chalcogenides, amorphous silicon, carbon, and polymer-nanoparticle composites. The most common memlist materials are hafnium oxide, titanium oxide, vanadium oxide, aluminum oxide, silicon dioxide, silicon nitride, or combinations thereof. Phase change materials such as chalcogenide glass and germanium antimontelluride (Ge2Sb2Te5) also exhibit memlist properties and can be used to form probe tips. In phase-change materials, the electric current flowing through the material heats and rapidly cools it, resulting in either an amorphous (insulating) or crystalline (conductive) state. In certain test methods, it is desirable that the probe tip be either conductive or insulating. To change the conductive state of the memlist material at the probe tip 108, the memlist material on the probe card 100A can be mechanically brought into contact with a conductive polymer plate. To make the memlist material conductive, a positive potential (set voltage) is applied to probes 104 and 106 with the conductive polymer plate electrically grounded. To switch the state of the memlist material to an insulating state, a negative potential (reset voltage) is applied to probes 104 and 106 with the conductive polymer plate electrically grounded. After the memlist material is programmed to be conductive or insulating, it is possible to test an LED using the probe card 100A, probes 104 and 106, and the memlist material.

[0059] Figure 1B is a side view of an LED wafer 100B. Wafer 100B may be a roll-to-roll test sheet for LEDs. Referring to Figure 1B, the LEDs are formed on a substrate 110. The substrate 110 may be silicon or sapphire. The LED may be a diode having an anode terminal 112 and a cathode terminal 114. If the LED is a diode, it can be forward biased to turn it on. One or more LEDs are arranged on the substrate 110. The anode terminal 112 and cathode terminal 114 are located on the front side 116 of the substrate 110. When the LED is lit, light is emitted from the front side 116 and / or bottom side 118 of the substrate 110.

[0060] Figure 1C is a schematic diagram showing the probe card 100A in close proximity to the LED wafer 100B. A first isolation gap 120 exists between the first probe 104 and the first terminal 112 of the LED. A second isolation gap 122 exists between the second probe 106 and the second terminal 114 of the LED. In other applications, isolation gaps 120 and 122 may be filled with other gases such as air, nitrogen, or argon. It is also possible to introduce a vacuum into isolation gaps 120 and 122. For example, when performing measurements in a scanning electron microscope (SEM) or transmission electron microscope (TEM), a vacuum is introduced into isolation gaps 120 and 122. The probe card 100A and / or LED wafer 100B are mounted on a movable stage, which is instructed to bring the probe card 100A and LED wafer 100B close together. The stage can be motor-driven, piezoelectric, or manually operated. A computer program can be used to operate the stage. For example, an LED wafer 100B is placed on the chuck of a wafer prober, and a probe card 100A is placed above the LED wafer 100B. A computer program (or manual operation) can be used to command the chuck, bringing the LED wafer 100B closer to the probe tip 108 of the probe card 100A. A tilt adjustment routine may be required to maintain a constant isolation gap 120 and 122 between all probe tips 108 and the first terminal 112 and the second terminal 114.

[0061] Continuing to refer to Figure 1C, probes 104 and 106 are aligned with the first terminal 112 and the second terminal 114, respectively. A fixed potential difference can be applied between probes 104 and 106. For example, a positive voltage is applied to probe 104 and probe 106 is electrically grounded. After applying the potential difference, the movable stage is moved step by step, bringing the probe tip 108 closer to the first terminal 112 and the second terminal 114 of the LED. As the movable stage moves, the isolation gaps 120 and 122 change and narrow. The change in isolation gaps 120 and 122 changes the capacitance between probe 104 and the first terminal 112, and between probe 106 and the second terminal 114. This change in capacitance, proportional to the change in isolation gaps 120 and 122, generates an operating current that forward-biases the LED, causing it to light up, emit light, or emit electromagnetic radiation. The forward current flows from probe 104 through the material forming the first probe tip 108, across the isolation gap 120 into the first terminal 112, then through the LED (diode) in the substrate 110, exits from the second terminal 114 across the isolation gap 122, and enters probe 106 through the material forming the second probe tip 108. Reference numeral 100C shows the state where probes 104 and 106 are close to terminals 112 and 114, as shown in Figure 1C. Figure 1D is an electrically equivalent circuit that models the flow of kinetic current as the isolation gaps 120 and 122 change.

[0062] Continuing to refer to Figure 1D, a voltage VA is applied to probe 104 and a voltage VC is applied to probe 106. The movable stage is instructed to bring probes 104 and 106 close to the first terminal 112 and the second terminal 114. Due to the movement speed of the movable stage and the potential difference between probes 104 and 106, a kinetic current flows from voltage VA through probe 104 (represented as resistor R1) and the material-forming probe tip 108 (represented as resistor R2). The kinetic current enters the first terminal 112 (represented as resistor R3) through the isolation gap 120 (represented as capacitor C1) and flows to the LED (represented as diode D1). Subsequently, the kinetic current travels from the LED through the second terminal 114 (represented as resistor R4), across the isolation gap 122 (represented as capacitor C2), enters the material-forming probe tip 108 (represented as resistor R5) of probe 106 (represented as resistor R6), and reaches probe 106.

[0063] Continuing to refer to Figure 1D, for the sake of discussion, the equivalent circuit can be further simplified to the currents flowing through biased variable capacitors C1 and C2. The kinetic current can be expressed as follows:

number

[0064] Continuing to refer to Figure 1D, equation 1 above shows that the speed at which the movable stage moves ∂z / ∂t can affect the amount of current flowing through the LED. As the speed of the movable stage increases, the kinetic current flowing through the LED increases, causing the LED to light up, emit light, or emit electromagnetic radiation. The intensity or brightness of the light emitted from the LED is directly proportional to the value of the kinetic current. The larger the kinetic current, the brighter the light emitted. When the movable stage moves so that the probe tip 108 approaches the first terminal 112 and the second terminal 114, the capacitance between the probe 104 and the first terminal 112 is given by the following equation.

number

number

[0065] As the movable stage moves and the probe tip 108 approaches the first terminal 112 and the second terminal 114, the isolation gap narrows and the LED lights up. When the movable stage stops moving, the LED turns off. It is necessary to safely discharge the charge accumulated in the isolation gap. For discharge, the LED wafer 100B is pulled back from the probe card 100A at a slow speed ∂z / ∂t to avoid generating a high reverse current in the light-emitting device.

[0066] Figure 1E includes plots of stage movement versus time, separation gap versus time, and kinetic current versus time. A potential difference is applied between probes 104 and 106. At time t0, the movable stage is instructed to move stepwise. As the stage moves incrementally in units of z steps, the separation gaps 120 and 122 narrow, and the kinetic current (i) inside the LED decreases. m A current begins to flow. This kinetic current causes the LED to light up and emit light or electromagnetic radiation. When the movable stage stops moving at time t1, the separation gap (gz) becomes constant. Since there is no stage movement, ∂z=0, and the change in capacitance ∂C is negligible. s = 0. As a result, no current flows according to Equation 1. Therefore, the LED turns off from time t1 to t2 when the stage movement stops. Although the LED is off, charge is accumulated in the isolation gap and must be carefully discharged to avoid causing electrostatic discharge that could destroy the LED. The discharge process is performed by instructing the movable stage to pull the LED wafer 100B away from the probe card 100A while a potential difference is applied to probes 104 and 106. The discharge process occurs from time t2 to t3. This discharge process generates a reverse current in the LED. To avoid generating a large reverse current, the movable stage moves at a smaller speed ∂z / ∂t from time t2 to t3. At time t3, the movable stage is returned to its original position and stops moving. At time t3, the LED is reset and it is possible to start another test cycle. The technique described above, namely the method of generating a current inside the LED by gradually approaching or contacting the LED with at least a voltage-biased probe, is called velocity probing. The voltage bias can be DC, AC, or a high-frequency signal.

[0067] Figure 1F is a schematic diagram showing the probe card 100A in contact with the LED wafer 100B. The LED can be switched on and off using the velocity probing technique described in the previous section. The probe tip 108 may be conductive or insulating. When a potential difference is applied between probes 104 and 106, if the material of the probe tip 108 is conductive, a direct potential difference is applied between the first terminal 112 and the second terminal 114 through mechanical contact between the probe tip 108 and the first terminal 112 and the second terminal 114. As long as the applied potential difference is greater than the LED's ignition voltage, a DC current flows through the LED, causing it to light up, emit light, or emit electromagnetic radiation. Reference numeral 100D refers to the arrangement in which the probe tips 108 of probes 104 and 106 are in contact with terminals 112 and 114, as shown in Figure 1F.

[0068] Figure 1G is the electrical equivalent circuit of Figure 1F, where potential VA is applied to probe 104 and potential VC is applied to probe 106. The DC current flows from probe 104 (represented as resistor R7) through the material of probe tip 108 (represented as resistor R9), through the first terminal 112 (represented as resistor R11), through the LED (represented as diode D2), and reaches the second terminal 114 (represented as resistor R12). The DC current exiting the second terminal 114 (represented as resistor R12) passes through the material of probe tip 108 (represented as resistor R10) and reaches probe 106 (represented as resistor R8).

[0069] Figure 1H includes a plot corresponding to the test method. Figure 1H is similar to Figure 1E, but the main difference is whether the forward DC current flowing through the LED is higher or lower based on the potential difference applied between probe 104 and 106 when the probe tip 108 contacts the first terminal 112 and the second terminal 114. During the time t1 to t2 when the probe tip 108 is in contact with the first terminal 112 and the second terminal 114, a forward DC current may flow through the LED due to the potential difference applied to the first terminal 112 and the second terminal 114.

[0070] Figure 1I is a schematic diagram of an LED wafer 100E. The array of LEDs 100F is manufactured on the same substrate 110. A single LED 100F may consist of a sapphire substrate, a GaN buffer layer, an n-GaN layer, a quantum well, a p-GaN layer, a quantum dot, a Bragg reflector, and metal contacts forming a first terminal 112 and a second terminal 114.

[0071] Figure 1J is a schematic diagram showing the top surface of probe card 100G. The array of probes 100H is manufactured on the same substrate 102. Each probe 104 and / or 106 may have a material attached to its tip that forms the probe tip 108. The pitch between probes 104 and 106 is the same as the pitch between the first terminal 112 and the second terminal 114 of LED 100F. Probe 104 may be electrically short-circuited with metal wiring 124. The metal wiring may be a transparent metal oxide such as indium tin oxide (ITO). Via 128 electrically connects metal wiring 124 on the top surface of substrate 102 to metal wiring 124 on the bottom surface of the same substrate 102. Probe 106 may be electrically short-circuited with metal wiring 126. Metal wiring 126 may be a transparent metal oxide such as indium tin oxide (ITO). Via 130 electrically connects the metal wiring 126 on the upper surface of board 102 to the metal wiring 126 on the lower surface of the same board 102. The screw holes 132 allow the probe card 100G to be aligned with a carrier board such as a printed circuit board (PCB) and screwed in.

[0072] Figure 1K is a schematic diagram showing the bottom of probe card 100G. Via 128 is electrically short-circuited to probe 104, and via 130 is electrically short-circuited to probe 106. Furthermore, via 128 is electrically short-circuited to contact pad 138 via metal trace 134. Similarly, via 130 is electrically short-circuited to contact pad 140 via metal wiring 136. External electrical signals are transferred to probes 104 and 106 via contact pads 138 and 140. Contact pads 138 and 140 may be flip-chip bonded to a printed circuit board or soldered to electrical wiring and connected to a source measuring unit or parameter analyzer.

[0073] In another embodiment, Figure 1L is a schematic diagram showing the top surface of probe card 100K. The array of probes 100H is manufactured on the same substrate 102. Each probe 104 and 106 may have material attached to its vertex forming a probe tip 108. The pitch between probes 104 and 106 is the same as the pitch between the first terminal 112 and the second terminal 114 of LED 100F. Vias 142 connect each probe 104 and 106 from the top to the bottom surface of substrate 102. An active or passive switch matrix is ​​integrated with the probe card. The active or passive switch matrix allows each probe 104 or 106 to be individually addressable, and each probe 104 or 106 to receive a specific electrical signal. When testing an LED wafer 100E with probe card 100K with an integrated switch matrix, individual LEDs 100F can be turned on / off simultaneously or individually based on the selection / addressing scheme of the switch matrix.

[0074] The lower part 100J of the probe card 100G (as shown in Figure 1K) is attached to the upper part 200B of the carrier 200A. The carrier 200A is shown in Figure 2A. The carrier 200A may be a printed circuit board (PCB). The carrier board 202 forms an opening 210 and has metal contacts 204 and 206. The metal contacts 204 and 206 may be metal pads, spring contacts, or pogo pins. The screw holes 132 on the probe card 100G are aligned with the tapped holes 208 on the carrier board 202. After alignment, the probe card 100G is secured to the carrier 200A using screws 304. At this time, the contact pads 138 and 140 of the probe card 100G make electrical contact with the metal contacts 204 and 206, respectively. Vias allow the metal pads 204 and 206 on the upper surface 200B of the carrier substrate 202 to be electrically connected to the lower surface 200C of the carrier substrate 202.

[0075] Figure 2B is a schematic diagram showing the underside of carrier 200A. Vias 212 and 214 electrically connect to metal pads 204 and 206, respectively. One end of the first electrical wiring may be soldered to via 212 and the other end connected to the source measuring unit. One end of the second electrical wiring may be soldered to via 214 and the other end connected to the source measuring unit.

[0076] Referring to Figure 3A, the probe card 100G is aligned with the LED wafer 100E. A vision system 302, such as a camera, is positioned above the probe card 100G so that probes 104 and 106 and the LED 100F can be viewed simultaneously. The vision system 302 may be a spectroradiometer or colorimeter capable of measuring the intensity, hue, color, and lumen of the light emitted from the LED 100F. The vision system 302 can scan the entire LED wafer 100E to collect the electroluminescent and photoluminescent characteristics of the LED 100F. A software program can be used to store the collected data. It is also possible to acquire emission information using multiple vision systems 302.

[0077] Referring to Figure 3B, the visual system 302 is located below the LED wafer 100E.

[0078] In another embodiment, continuing with reference to Figures 3A and 3B, probes 104 and 106 are aligned to the first terminal 112 and the second terminal 114, with isolation gaps 120 and 122 fixed. While probe 106 is electrically grounded, an AC signal or a high-frequency signal is applied to probe 104. The high-frequency signal may be a radio frequency (RF) signal, a microwave signal, an infrared signal, or a terahertz signal. If the frequency of the AC signal or high-frequency signal corresponds to the resonant frequency of the light-emitting device 100F, a resonant current may be generated within the light-emitting device 100F. At the resonant frequency, the kinetic current flowing through the light-emitting device is internally amplified. The resonant current generates light or electromagnetic radiation from the light-emitting device. Since the AC or high-frequency signal is an AC signal, the light-emitting device can be turned on / off in one cycle. The intensity or brightness of the light emission is directly proportional to the amplitude or magnitude of the applied AC or high-frequency signal. The technique of turning the light-emitting device on / off at the resonant frequency is known as resonant probing. Using the high-frequency vision system 302, it is possible to measure the emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle of the light-emitting device 100F.

[0079] Figure 4 is a schematic diagram of the imager 400. The imager 400 includes an image sensor 404 positioned on a frame 402. The image sensor 404 has the ability to detect and transmit electromagnetic information used to form an image. The image sensor 404 can be an active pixel sensor made of a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS). The detection mechanism of the image sensor 404 is diverse, including visible light, ultraviolet light, infrared light, heat, gigahertz band, ultrasound, terahertz band, radar, and sonar. The image sensor 404 is directly mounted on the LED wafer 100E or probe card 100G to generate an image of the LED 100F. The image sensor 404 is the same size as the LED wafer 100E, enabling parallel imaging of all LEDs 100F on the LED wafer 100E. The image sensor 404 can be operated using a computer, and the imaging results can be displayed on a monitor. Based on the generated images of the LED100F, a computer vision program can be used to determine which LED100F passes or fails quality inspection based on the color and / or intensity of the light or electromagnetic radiation emitted from the LED100F. The computer vision program can also provide important yield analysis data, such as classifying the LED100F based on their characteristics: luminous intensity, luminous output, luminous color, luminous brightness, luminous chromaticity, luminous peak wavelength, and luminous angle. Process variation information across the entire LED wafer 100E can also be determined using the yield program by monitoring the distribution of pass or fail LED100F across the entire wafer.

[0080] In another embodiment, the image sensor 404 can be a spectroradiometer or colorimeter capable of measuring the color, brightness, chromaticity, peak wavelength, and radiation angle of light or electromagnetic radiation emitted from the LED 100F.

[0081] In another embodiment, the image sensor 404 is composed of a material or device that is photon sensitive to the emission wavelength of light or electromagnetic radiation emitted from the LED 100F. Such a photon-sensitive material or device can be a diode or a field-effect transistor.

[0082] Figure 5A is a schematic diagram of the imager 400 placed on the probe card 100G. Electromagnetic waves emitted from the LED 100F pass through the probe card substrate 102 and reach the image sensor 404. The image sensor 404 measures and displays information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle.

[0083] Figure 5B is a schematic diagram of the imager 400 attached to the LED wafer 100E. Electromagnetic radiation emitted from the LED 100F passes through the LED wafer substrate 110 and reaches the image sensor 404. The image sensor 404 measures and displays LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle. The imager 402 and LED wafer 100E can be placed on the chuck of a wafer prober.

[0084] In another embodiment, continuing with reference to Figure 5B, the image sensor 404 can be used as an excitation source to light up the LED 100F and / or emit electromagnetic radiation. A laser is an example of an excitation source. A visual system 302 positioned above the LED wafer 100E can measure and display LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle.

[0085] Figure 6 is a schematic diagram of the probe card 100G integrated with the photon sensor 602. Each photon sensor 602 is sensitive to electromagnetic radiation emitted from a light-emitting device. An example of a photon sensor is the image sensor 404 shown in Figure 4. The photon sensor 602 has the same functions and operation as the image sensor 404 in Figure 4. This photon sensor 602 measures and displays light or electromagnetic radiation information such as radiation intensity, radiation output, radiation color, radiance, radiation chromaticity, radiation peak wavelength, and radiation angle.

[0086] Figure 7A is a schematic diagram of a probe card 100G mounted on top of an LED wafer 100E. The vision system 302 is positioned above the probe card 100G. The LED wafer 100E consists of a vertical LED 700A having a first terminal 112 located on the upper surface 116 of the LED substrate 110 and a second terminal 114 located on the lower surface 118 of the LED substrate 110. The probe 104 is aligned with the first terminal 112, and a potential difference is applied between the probe 104 and the second terminal 114. At this time, either the probe card 100G or the LED wafer 100E moves toward the other. The movement of the probe card 100G and / or the LED wafer 100E is performed at a constant speed, changing the isolation gap 702 and causing a kinetic current to flow through the vertical LED 700A. This current flow causes the LED 700A to light up, emit light, and / or emit electromagnetic radiation. Using the vision system 302, the on / off state of LED700A can be imaged, and LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle can be measured and displayed. When the LED wafer 100E is separated from the probe card 100G, LED700A turns off.

[0087] Figure 7B is a schematic diagram of the electrical equivalent circuit when the bias (voltage VA) probe 104 (represented as resistor R13), the material forming the probe tip 108 (represented as resistor R14), and the first terminal 112 of the LED 700A (represented as resistor R15) are in close proximity. The series resistance of the probe 104 is resistor R13, the material forming the probe tip 108 is resistor R14, the isolation gap is variable capacitor C3, and the resistance of the first terminal is represented by resistor R15. Diode D3 represents a vertical light-emitting device, capacitor C4 is the internal capacitance of the light-emitting device connected to the second terminal 114, and the second terminal is represented by resistor R16. The potential of voltage VD is applied to the second terminal 114.

[0088] Figure 7C is a schematic diagram of the electrically equivalent circuit when a bias (voltage VA) probe 104 (represented as resistor R17) and the material constituting the probe tip 108 (represented as resistor R18) are in contact with the first terminal 112 (represented as resistor R19) of the LED 700A. The series resistance of probe 104 is represented by resistor R17, and the material forming the probe tip 108 is represented by resistor R18. The resistance of the first terminal is resistor R19, and diode D4 represents the vertical light-emitting device. Capacitor C6 is the internal capacitance of the light-emitting device connected to the second terminal 114, and the second terminal is represented as 114. A potential of voltage VD is applied to the second terminal 114. The bias (voltage VD) to the second terminal 114 can be applied by the chuck of the wafer prober.

[0089] In another embodiment, continuing with reference to Figure 7A, an AC or high-frequency signal is applied to the probe 104 while the probe 104 is aligned with the first terminal 112, the isolation gap 702 is fixed, and the second terminal 114 is electrically grounded. This high-frequency signal may be a radio frequency (RF), microwave signal, infrared signal, or terahertz signal. If the frequency of the AC or high-frequency signal corresponds to the resonant frequency of the light-emitting device 700A, a resonant current may be generated within the light-emitting device 700A. At the resonant frequency, the kinetic current flowing through the light-emitting device is internally amplified. The resonant current generates light or electromagnetic radiation from the light-emitting device. Since the AC or high-frequency signal is an AC signal, the light-emitting device can be turned on / off in one cycle. The intensity or brightness of the light emission is directly proportional to the amplitude or magnitude of the applied AC or high-frequency signal. The technique of turning the light-emitting device on / off at the resonant frequency is known as resonant probing. The high-frequency vision system 302 can be used to measure the emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle of the light-emitting device 700A. To turn off LED 700A, move the LED wafer 100E away from the probe card 100G.

[0090] Figure 8 is a schematic diagram of a probe card 100G mounted on top of an LED wafer 100E. The imager 400 is positioned above the probe card 100G. The LED wafer 100E is equipped with a vertical LED 700A, with a first terminal 112 located on the upper surface 116 of the LED wafer substrate 110 and a second terminal 114 located on the lower surface 118 of the LED wafer substrate 110. When the probe 104 is aligned with the first terminal 112, a potential difference is applied between the probe 104 and the second terminal 114, causing either the probe card 100G or the LED wafer 100E to move toward each other. The movement of the probe card 100G and / or the LED wafer 100E is performed at a constant speed, changing the isolation gap 702 and causing a kinetic current to flow within the vertical LED 700A. This current flow causes the LED 700A to light up, emit light, and / or emit electromagnetic radiation. The image sensor 404 is used to capture images of the on / off state of the LED 700A, as well as to measure and display LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle. To turn off the LED 700A, the LED wafer 100E is moved away from the probe card 100G.

[0091] Figure 9 is a schematic diagram of a probe card 100G mounted on top of an LED wafer 100E. The probe card 100G is integrated with a photon sensor 602. The LED wafer 100E is equipped with a vertical LED 700A, with a first terminal 112 located on the upper surface 116 of the LED substrate 110 and a second terminal 114 located on the lower surface 118 of the LED wafer substrate 110. The probe 104 is aligned with the first terminal 112, and a potential difference is applied between the probe 104 and the second terminal 114 as the probe card 100G and / or the LED wafer 100E move closer to each other. The probe card 100G and / or the LED wafer 100E move at a constant speed, and the separation gap 702 changes, causing a kinetic current to flow through the vertical LED 700A. This current flow causes the LED 700A to light up. The photon sensor 602 can be used to image the on / off state of the LED 700A, as well as to measure and display LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle. To turn off the LED 700A, move the LED wafer 100E away from the probe card 100G.

[0092] Figure 10 is a schematic diagram of a probe card 100G mounted on top of an LED wafer 100E. The probe card 100G consists of a single probe 104 and a material forming a probe tip 108. The probe 104 is formed of a transparent metal oxide such as indium tin oxide (ITO), and the material forming the probe tip 108 can be a transparent material such as polydimethylsiloxane (PDMS) or an epoxy photoresist such as SU-8. The material forming the probe tip 108 can also be a memlist material. The probe 104 and probe tip 108 can be made as large as the size of the LED wafer 100E so that all vertical light-emitting devices on the LED wafer 100E can be tested in parallel. The LED wafer 100E is equipped with vertical LEDs 700A, with a first terminal 112 located on the upper surface 116 of the LED substrate 110 and a second terminal 114 located on the lower surface 118 of the LED substrate 110. While a potential difference is applied between the probe 104 and the second terminal 114 of the LED, the probe card 100G and / or the LED wafer 100E are moved toward each other. The probe card 100G and / or the LED wafer 100E are moved at a constant speed, changing the isolation gap 702 and causing a kinetic current to flow through the vertical LED 700A. This current causes the LED 700A to light up. The lighting and extinguishing of the LED 700A can be imaged using the photon sensor 602 or the vision system 302, and LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle can be measured and displayed. To turn off the LED 700A, the LED wafer 100E is moved away from the probe card 100G.

[0093] Continuing to refer to Figure 10, the LED wafer 100E is scanned under the probe card 100G by moving the XYZ moving stage of the wafer prober. For example, the LED wafer 100E is placed on the chuck of the wafer prober, and velocity probing or resonant probing is performed at each position. Then, the chuck is moved along the XY plane, and new velocity probing or resonant probing is performed. At each position, an image of a single or array of light-emitting devices can be acquired using the vision system 302. Maps of emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle can be acquired and displayed on a computer monitor during the scanning process.

[0094] Figure 11A is a schematic diagram of a probe card 100G placed on an LED wafer 100E. Probe 104 is positioned with an intentional offset of 1102 relative to the first terminal 112, and probe 106 is also positioned with an intentional offset of 1102 relative to the second terminal 114. A fixed isolation gap 1104 exists between probes 104 and 106 and the first terminal 112 and the second terminal 114. The light-emitting device is switched on by applying a potential difference between probes 104 and 106 and moving either the probe card 100G or the LED wafer 100E in the x-direction (lateral direction). As a result, probe 104 is aligned with the first terminal 112 and probe 106 is aligned with the second terminal 114, as shown in Figure 11B. By moving either the probe card 100G or the LED wafer 100E laterally at a constant speed, a forward kinetic current is generated. This current penetrates the material forming the probe tip 108 from the probe 104, flows into the first terminal 112 across the separation gap 1104, passes through the LED, crosses the separation gap 1104 from the second terminal 114, and enters the probe 106 through the material forming the probe tip 108. This kinetic current can be expressed as follows.

number

[0095] Continuing to refer to FIGS. 11A, 11B, and Equation 4, at the fixed separation gap 1104, the capacitance between the probe tip 108 and the first terminal 112 is given by the following equation. <00​​​​​​​​​​​​​​​​​​​​​​​​​ Equation 7 suggests that the kinetic current through the light-emitting device can be further increased by increasing the dielectric constant of the substance or gas present in the separation gap 1104, and / or increasing the width of the first terminal 112, and / or decreasing the separation gap 1104. As the movable stage moves laterally to align probe 104 to the first terminal 112 and probe 106 to the second terminal 114, a kinetic current flows inside the LED as the misalignment length 1102 decreases. The maximum kinetic current is achieved when the misalignment length approaches zero and the probes and terminals are fully aligned. When the lateral movement of either the probe card 100G or the LED wafer 100E stops, the kinetic current stops and the LED turns off. To reset the light-emitting device, either the probe card 100G or the LED wafer 100E is returned to its original position, and probes 104 and 106 are misaligned again relative to the first terminal 112 and the second terminal 114. The reset is performed at a potential difference V 104_106 This is performed by moving the stage laterally at the same or lower speed ∂x / ∂t while maintaining the separation gap g. The on / off state of the light-emitting device can be observed using the vision system 302. The test method described in this section is called lateral probing.

[0098] The lateral probing technique described in the previous section can also be used to test vertical light-emitting devices in parallel, as shown in Figure 7A. Referring to Figure 7A, in the initial state, probe 104 is misaligned with the first terminal 112 of the light-emitting device 700A. With the isolation gap 702 fixed, a potential difference V exists between probe 104 and the second terminal 114. 104_106 Apply a voltage. Move either the probe card 100G or the LED wafer 100E in the x-direction (lateral direction) at a constant speed of ∂x / ∂t to generate an operating current in the LED device 700A. When the movement of either the probe card 100G or the LED wafer 100E stops, the LED turns off. To reset the light-emitting device, apply a potential difference V. 104_106While maintaining the separation gap g, either the probe card 100G or the LED wafer 100E is returned to its original position at the same or slower speed ∂x / ∂t. The on and off states of the LED device 700A can be observed using the visual system 302.

[0099] Figure 12 is a schematic diagram of a probe card 100G mounted on top of an LED wafer 100E. The probe card 100G consists of a single probe 104 and a material forming the probe tip 108. The probe 104 is formed from a transparent metal oxide such as indium tin oxide (ITO), and the material forming the probe tip 108 can be a transparent material such as polydimethylsiloxane (PDMS) or an epoxy photoresist such as SU-8. To prevent the material forming the probe tip 108 from scratching or damaging the terminals 112 upon contact, the material forming the probe tip 108 can be made from a reversibly deformable polymer. The probe 104 and probe tip 108 can be made to be roughly the same size as the LED wafer 100E so that all vertical light-emitting devices on the LED wafer 100E can be tested in parallel. The LED wafer 100E has a vertical LED 700A, with a first terminal 112 located on the upper surface 116 of the LED substrate 110 and a second terminal 114 located on the lower surface 118 of the LED substrate 110. While a potential difference is applied between the probe 104 and the second LED terminal 114, the probe card 100G and / or the LED wafer 100E are moved toward each other. The movement of the probe card 100G and / or the LED wafer 100E is performed at a constant speed, changing the isolation gap 702 and causing a kinetic current to flow through the vertical LED 700A. This current flow causes the LED 700A to light up. The movable stage stops moving when the material forming the probe tip 108 mechanically contacts the terminal 112. A motion sensor 1202 may be integrated into the probe card 100G or the LED wafer 100E to detect when the material forming the probe tip 108 contacts or approaches the first terminal 112. Examples of motion sensors 1202 include force sensors, capacitive sensors, proximity sensors, and light sensors. When the LED wafer 100E is separated from the probe card 100G, the LED 700A is turned off. The photon sensor 602 or vision system 302 can be used to image the on / off state of the LED 700A and to measure and display LED emission information such as emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and emission angle.

[0100] Furthermore, the test techniques described in the preceding paragraphs are not limited to testing light-emitting devices having a first terminal 112 and a second terminal 114. The probe card 100G can also be used to test light-emitting devices that do not have any terminals. The materials forming probes 104 and / or 106 and probe tip 108 can be tested by directly contacting the LED 100F or 700A. In addition, the entire operation of the movable stage can be performed by stepwise changing the potential difference between at least one probe and at least one terminal of the light-emitting device, thereby allowing the light-emitting device to be switched on, lit, and / or emit electromagnetic radiation. It should be noted that the non-contact test techniques described in this application are non-destructive.

[0101] All definitions defined and used in this Agreement should be understood to supersede dictionary definitions, definitions incorporated by reference in other documents, and / or the ordinary meanings of the terms defined.

[0102] As used herein and in the claims, the indefinite articles "a" and "an" should be interpreted as meaning "at least one" unless otherwise specified.

[0103] As used herein and in the claims, the phrase "and / or" should be interpreted as meaning "either one or both" of the combined elements; that is, elements that exist jointly in some cases and separately in others. The same should be interpreted for any multiple elements listed in "and / or," meaning "one or more" of the thus connected elements. In addition, there may be any elements other than those specifically identified in the "and / or" clause (whether related to the identified elements or not).

[0104] As used herein and in the claims, “or” should be understood to be synonymous with “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” is interpreted as inclusive; that is, it includes at least one of the number of elements or the list, but may include more, and optionally additional items not on the list. Only terms indicating clear exceptions, such as “any one” or “exactly one,” or the term “consisting of” as used in the claims, refer to including exactly one element from the number of elements or the list. In general, as used herein, the term “or” is interpreted as indicating an exclusive choice (i.e., “one or the other, but not both”) only when preceded by terms indicating exclusivity, such as “either,” “one,” “only one,” or “exactly one.”

[0105] As used herein and in the claims, the expression “at least one” should be interpreted as meaning at least one element selected from any one or more elements in a list of elements, and does not necessarily mean at least one of each element specifically enumerated in the list of elements, nor does it exclude any combination of elements in the list of elements. This definition also acknowledges that elements other than those specifically identified in the list of elements referred to by the phrase “at least one” may exist, whether or not they are related to those specifically identified elements.

[0106] Furthermore, unless otherwise explicitly stated, with respect to any method claimed herein that includes multiple steps or actions, the order of the steps or actions of such method is not limited to the order in which they are described.

[0107] In the claims and the above specification, all transitional phrases such as “include,” “contain,” “have,” “contain,” “involve,” “hold,” and “compose” should be interpreted as open; that is, they include but are not limited to these. However, only the transitional expressions “consisting of” and “consisting essentially of” are closed or semi-closed transitional expressions, respectively.

[0108] Examples of the subject matter described above can be implemented in one of many ways. For example, some aspects can be implemented using hardware, software, or a combination thereof. If any aspect is implemented at least partially in software, the software code can run on any suitable processor or group of processors, whether it is delivered to a single device or computer, or distributed across multiple devices / computers.

[0109] This disclosure can be implemented as a system, method, and / or computer program product at any level of technical detail. The computer program product may include a computer-readable storage medium (or set of media) having computer-readable program instructions for causing a processor to perform aspects of this disclosure.

[0110] Computer-readable storage media are tangible devices capable of holding and storing instructions used by instruction execution devices. Computer-readable storage media include, but are not limited to, electronic memory, magnetic memory, optical memory, electromagnetic memory, semiconductor memory, or appropriate combinations thereof. More specific examples of computer-readable storage media include, but are not limited to, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or grooved projection structures (including instructions recorded therein), and appropriate combinations thereof. The computer-readable storage media used herein should not be interpreted as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses passing through fiber optic cables), or electrical signals transmitted through conductors.

[0111] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing unit, or to an external computer or external storage device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network). The network may consist of copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface within each computing / processing unit receives computer-readable program instructions from the network and transfers the computer-readable program instructions for storage on a computer-readable storage medium within that computing / processing unit.

[0112] Computer-readable program instructions for performing the operations of the Disclosure may be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data for integrated circuits, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk and C++, or written in a procedural programming language (e.g., the "C" programming language or a similar programming language). Computer-readable program instructions are source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as C++, or procedural programming languages ​​such as the "C" programming language. Computer-readable program instructions may be fully executed on the user's computer, partially executed on the user's computer and operate as a standalone software package, partially executed on the user's computer and partially executed on a remote computer, or fully executed on a remote computer or server.In the latter scenario, the remote computer is connected to the user's computer via any type of network, including local area networks (LANs) and wide area networks (WANs), or to an external computer (e.g., via the Internet through an Internet service provider). In some examples, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), can execute computer-readable program instructions and perform aspects of this disclosure by leveraging state information of computer-readable program instructions to personalize the electronic circuits.

[0113] Aspects of this disclosure are described herein by reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products based on the examples of disclosure. It will be understood that each block in the flowcharts and / or block diagrams, as well as any combination of blocks within the flowcharts and / or block diagrams, can be implemented by computer-readable program instructions.

[0114] Computer-readable program instructions are provided to the processor of a dedicated computer or other programmable data processing device, enabling the creation of a machine. This creates a means for instructions executed via the processor of a computer or other programmable data processing device to implement the functions / operations specified in flowcharts and / or block diagram blocks. These computer-readable program instructions can also be stored in computer-readable storage media that can instruct computers, programmable data processing devices, and / or other devices to function in a particular way. Thus, the computer-readable storage media containing the instructions becomes a product containing instructions that implement aspects of the functions / operations specified in flowcharts and / or block diagrams or sets of blocks.

[0115] Computer-readable program instructions can also be loaded into a computer, other programmable data processing device, or other device, which then executes a series of operational steps on the computer, other programmable device, or other device, generating a computer implementation process. As a result, the instructions executed on the computer, other programmable device, or other device implement the functions / operations specified by the blocks or groups of blocks in the flowchart and / or block diagram.

[0116] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products based on various examples of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or part of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative embodiments, the functions shown in a block may be executed in an order different from the order shown in the figure. For example, two consecutively shown blocks may actually be executed substantially simultaneously, or blocks may be executed in reverse order depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, as well as combinations of blocks in a block diagram and / or flowchart, may be implemented by a dedicated hardware-based system or a combination of dedicated hardware and computer instructions that performs a specified function or operation.

[0117] Other embodiments are included in the scope of the following claims and any other claims for which the applicant may be entitled.

[0118] While various examples are described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures to achieve the functions and / or results and / or advantages described herein. Each such variation and / or modification will be considered to fall within the scope of the examples described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are illustrative, and that actual parameters, dimensions, materials, and / or configurations will depend on the specific application or group of applications in which this teaching is used. Those skilled in the art will be able to recognize or identify many equivalents to the specific embodiments described herein using experiments within the usual scope. Thus, it should be understood that the embodiments described herein are presented only as examples, and that the embodiments can be practiced in ways different from those illustrated within the scope of the appended claims and their equivalents. The examples in this disclosure are directed to the individual features, systems, articles, materials, kits, and / or methods described herein. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods is also within the scope of this disclosure, provided that they do not contradict each other.

Claims

1. A method for testing light-emitting devices, Prepare a probe card with at least two probes, A potential difference is applied between the first and second probes of at least two probes, Align the first probe and the second probe with the first terminal and the second terminal of the light-emitting device, respectively, and further The movable stage is commanded to bring the first probe and the second probe close to the first and second terminals of the light-emitting device. The movement speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current switches on the light-emitting device, turns it on, makes it emit light, or emits electromagnetic radiation. A method for testing a light-emitting device, comprising the step of switching off the light-emitting device by stopping the movement of a movable stage and / or increasing the isolation gap between one of at least two probes and either a first or second terminal of the light-emitting device.

2. The test method according to claim 1, wherein the first terminal and the second terminal of the light-emitting device are arranged on the same side of the substrate of the light-emitting device.

3. The test method according to claim 1, wherein the first terminal and the second terminal of the light-emitting device are arranged on opposite sides of the substrate of the light-emitting device.

4. The test method according to claim 1, wherein the first terminal is an anode and the second terminal is a cathode, or the first terminal is a cathode and the second terminal is an anode.

5. The test method according to claim 1, wherein a light-emitting device wafer is scanned on a biased probe among at least two probes, and during this time, an image sensor generates an image of the light-emitting device.

6. The test method according to claim 1, wherein the intensity or output of light emission or electromagnetic radiation is directly proportional to the generated kinetic current flowing inside the light-emitting device.

7. The test method according to claim 1, wherein the amount of kinetic current is directly proportional to the moving speed of the movable stage.

8. The test method according to claim 1, wherein the amount of kinetic current is directly proportional to the potential difference applied between the first terminal and the second terminal of the light-emitting device.

9. The test method according to claim 1, wherein the amount of kinetic current is inversely proportional to the isolation gap between at least one of the two probes and one of the first or second terminals of the light-emitting device.

10. The test method according to claim 1, wherein the amount of kinetic current is directly proportional to the area of ​​either the first terminal or the second terminal of the light-emitting device.

11. The test method according to claim 1, wherein the amount of kinetic current is directly proportional to the dielectric constant of the substance or gas present between the tip of at least one of the two probes and either the first terminal or the second terminal of the light-emitting device.

12. The test method according to claim 1, wherein light emission or electromagnetic radiation is measured by a vision system.

13. The test method according to claim 12, wherein the vision system is capable of measuring luminescence intensity, luminescence output, luminescence color, luminescence brightness, luminescence chromaticity, emission peak wavelength, and emission angle.

14. The probe card is circuit board and Equipped with at least two probes made from conductive material, The test method according to claim 1, wherein at least one of the two probes has a probe tip comprising a memlist material or polymer.

15. The probe card according to claim 14, wherein the memlist material is configured to switch its state from a conductive state to an insulating state and vice versa.

16. The probe card according to claim 14, wherein the memlist material is a deformable material configured to deform reversibly when pressed against the device under test.

17. The probe card according to claim 14, wherein the memlist material comprises a metal oxide, a chalcogenide, amorphous silicon, carbon, and / or polymer nanoparticles.

18. The probe card according to claim 14, wherein the memlist material is a phase change material.

19. The phase change material according to claim 18, comprising chalcogenide glass or germanium antimontelluride.

20. The probe card according to claim 14, wherein the polymer is a deformable material configured to deform reversibly when pressed against the device under test.

21. The probe card according to claim 14, wherein the polymer comprises polydimethylsiloxane (PDMS) or an epoxy photoresist.

22. The probe card according to claim 14, wherein the active or passive switch matrix is ​​integrated integrally with the probe card.

23. The probe card according to claim 14, wherein at least one photon sensor is integrally integrated into the probe card.

24. The probe card according to claim 23, wherein the photon sensor is configured to measure and display emitted light or electromagnetic radiation emission information, including emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, and / or emission angle.

25. A method for testing light-emitting devices, Prepare a probe card with at least one probe, Align the first probe of at least one probe with the first terminal of the light-emitting device, A potential difference is applied between the first probe and the second terminal of the light-emitting device, and further The movable stage is commanded to bring the first probe close to or in contact with the first terminal of the light-emitting device. The movement speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current switches on the light-emitting device, turns it on, causes it to emit light, and releases electromagnetic radiation. A method for testing a light-emitting device, comprising the step of switching off the light-emitting device by stopping the movement of a movable stage and / or increasing the isolation gap between a first probe and either a first or second terminal of the light-emitting device.

26. The test method according to claim 25, wherein the movement of the movable stage is stopped when a motion sensor detects that the probe tip of at least one probe is approaching or in contact with a first terminal of a light-emitting device.

27. The test method according to claim 26, wherein the motion sensor is integrally integrated with the substrate of a probe card or a light-emitting device wafer.

28. The test method according to claim 26, wherein the motion sensor is a force sensor, a capacitance sensor, a proximity sensor, or a light sensor.

29. A method for testing light-emitting devices, Prepare a probe card with at least two probes, Align the first of at least two probes with the first terminal of the light-emitting device, and align the second of at least two probes with the second terminal of the light-emitting device. A potential difference is applied between the first probe and the second probe, and further The movable stage is commanded to bring the first probe and the second probe into contact with the first terminal and the second terminal of the light-emitting device, respectively. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current switches on the light-emitting device, turns it on, makes it emit light, or emits electromagnetic radiation. When the first probe and the second probe make contact with the first terminal and the second terminal, respectively, a direct current flows within the light-emitting device. A direct current switches on a light-emitting device, turns it on, makes it emit light, or causes it to emit electromagnetic radiation. A method for testing a light-emitting device, comprising the steps of switching off the light-emitting device, which is achieved by stopping the movement of a movable stage and increasing the isolation gap between at least one of two probes and either a first or second terminal of the light-emitting device.

30. A method for testing light-emitting devices, Prepare a probe card with at least one probe, Align the first probe with the first terminal of the light-emitting device. A fixed isolation gap is formed between the first probe and the first terminal of the light-emitting device. An AC or high-frequency signal is applied to the first probe, and the frequency of the AC or high-frequency signal is the resonant frequency of the light-emitting device. The second terminal of the light-emitting device is electrically grounded, and further A test method comprising the step of generating a resonant current within a light-emitting device, thereby switching on the light-emitting device, lighting it up, causing it to emit light, or emitting electromagnetic radiation.

31. A method for testing light-emitting devices, Prepare a probe card with at least two probes, Align the first of at least two probes with the first terminal of the light-emitting device, and align the second of at least two probes with the second terminal of the light-emitting device. A fixed isolation gap is formed between the first probe and the first terminal of the light-emitting device. An AC or high-frequency signal is applied to the first probe, and at the same time, the second probe is electrically grounded. The frequency of the AC or high-frequency signal is the resonant frequency of the light-emitting device, and further... A test method comprising the step of generating a resonant current within a light-emitting device, thereby switching on the light-emitting device, lighting it up, causing it to emit light, or emitting electromagnetic radiation.

32. The test method according to claim 30 or 31, wherein the intensity or luminosity of light emission or electromagnetic radiation is directly proportional to the amplitude or magnitude of the applied alternating current or high-frequency signal.

33. The test method according to claim 30 or 31, wherein the high-frequency signal is a radio frequency signal, a microwave signal, an infrared signal, or a terahertz signal.

34. The test method according to claim 32, wherein the vision system is used to measure luminescence intensity, luminescence output, luminescence color, luminescence brightness, luminescence chromaticity, luminescence peak wavelength, or luminescence angle.

35. The test method according to claim 30 or 31, wherein the image sensor is mounted on a probe card or a substrate of a light-emitting device.

36. The test method according to claim 35, wherein the image sensor is configured to measure emission intensity, emission output, emission color, emission brightness, emission chromaticity, emission peak wavelength, or emission angle.

37. The test method according to claim 35, wherein the image sensor is made of a material or device that has photon sensitivity to the emission wavelength of light or electromagnetic radiation emitted from a light-emitting device.

38. The test method according to claim 37, wherein the material or device is a diode or a field-effect transistor.

39. The test method according to claim 37, wherein the image sensor is an excitation source configured to excite a light-emitting device, switch it on, light it up, cause it to emit light, and / or emit electromagnetic radiation.

40. The test method according to claim 39, wherein the excitation source is a laser.

41. A method for testing light-emitting devices, Prepare a probe card with at least one probe, A separation gap is formed between the first probe of at least one probe and the first terminal of the light-emitting device. The first probe is misaligned relative to the first terminal of the light-emitting device. A potential difference is applied between the first probe and the second terminal of the light-emitting device, and further The movable stage is commanded to align the first probe laterally with the first terminal of the light-emitting device. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current switches on the light-emitting device, turns it on, makes it emit light, or emits electromagnetic radiation. A test method comprising the step of switching off a light-emitting device by stopping the lateral movement of a movable stage and / or shifting the position of a first probe relative to a first terminal of the light-emitting device.

42. A method for testing light-emitting devices, Prepare a probe card with at least two probes, A first isolation gap is formed between at least one of the two probes, at least the first probe, and the first terminal of the light-emitting device. A second isolation gap is formed between the second probe of at least two probes and the second terminal of the light-emitting device. The first probe is misaligned relative to the first terminal of the light-emitting device. The second probe is misaligned relative to the second terminal of the light-emitting device. A potential difference is applied between the first probe and the second probe, and further The movable stage is commanded to align the first probe and the second probe laterally with the first and second terminals of the light-emitting device, respectively. The speed of the movable stage generates a kinetic current within the light-emitting device. The generated kinetic current switches on the light-emitting device, turns it on, makes it emit light, or emits electromagnetic radiation. A test method comprising the step of switching off a light-emitting device by stopping the lateral movement of a movable stage and / or shifting the position of a first probe and a second probe relative to the first and second terminals of the light-emitting device.

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