A passivation repair method for an ITO sputtering target for silicon-based micro-OLED manufacturing and application thereof

Abstract

The application provides a passivation repair method for an ITO sputtering target for preparing a silicon-based Micro-OLED and application thereof. The passivation repair method comprises the following steps: obtaining standby state parameters of the ITO target, and determining the passivation level of the surface of the ITO target according to the standby state parameters; the passivation layer comprises a loose adsorption pollution layer and a polarization high-resistance insulating layer from outside to inside; in an oxygen-free environment, the loose adsorption pollution layer of the ITO target is removed by using a physical peeling method, then a reverse negative voltage pulse electric field is applied to perform depolarization treatment on the polarization high-resistance insulating layer; the discharge state feedback parameters of the ITO target are monitored in real time to dynamically adjust the pulse sputtering parameters; and steady sputtering deposition of the ITO thin film is performed to form an ITO anode layer of the silicon-based Micro-OLED. The application realizes complete resetting of the target state and high stability of the sputtering process, and provides reliable guarantee for high-performance preparation of the silicon-based Micro-OLED.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a passivation repair method for ITO sputtering targets used in the fabrication of silicon-based Micro-OLEDs and its application. Background Technology

[0002] Silicon-based Micro-OLED devices possess ultra-high resolution, ultra-high pixel density, and micro / nano-thin electrode structures, making them widely used in AR / VR near-eye displays, high-end wearable devices, and other fields. Among them, the ITO anode has extremely high requirements for the oxygen vacancy ratio, interface defects, leakage current, and film thickness uniformity of the thin film, and its process window is much smaller than that of traditional OLED and LCD devices.

[0003] Currently, magnetron sputtering equipment for mass production of ITO generally employs pulsed DC sputtering, a fixed duty cycle, and a low-oxygen current-limiting process. However, during mass production, it has been found that after the chamber has been idle for more than 15 minutes, trace amounts of water vapor and hydrocarbons adsorb onto the surface of the ITO target, rapidly forming a thin, polarized, high-resistivity passivation layer. After the equipment is powered, the target voltage is clamped at around 240V, forming a stable voltage plateau that lasts for about 20 seconds. Only after the passivation layer is slowly consumed can the voltage gradually climb to a steady state of 375V. Therefore, this stagnation at the 240V voltage plateau is the core bottleneck restricting mass production—the plasma state is weak and unstable during this plateau stage, making it highly susceptible to micro-arc arcing and localized nodulation on the target surface, resulting in deterioration of the film uniformity. Furthermore, the increased passivation layer thickness after prolonged equipment idle time further exacerbates the voltage ramp-up lag problem.

[0004] To address the aforementioned issues, the traditional industry solution is to extend the pre-sputtering time to activate the target material. However, extending the pre-sputtering time reduces production capacity, increases target material loss, and easily generates particulate contamination. Furthermore, there are no targeted depolarization and resistance-breaking solutions in the industry; the common approach is a power ramp-up mode with a fixed duty cycle, which can only clean minor deposits on the target material surface and cannot penetrate or eliminate the deep polarization high-resistance insulating layer. This results in persistent polarization residues, poor repair consistency, and difficulty in adapting to the target material state recovery requirements under different standby times and passivation levels, falling far short of meeting the ultra-low defect mass production requirements of Micro-OLEDs.

[0005] Therefore, there is an urgent need to develop an efficient and adaptive process for repairing the passivation state of ITO targets and restoring sputtering stability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a passivation repair method for ITO sputtering targets used in silicon-based Micro-OLED fabrication and its application. The passivation repair method provided by this invention achieves systematic repair of the passivation state of the ITO target and closed-loop control of the entire sputtering process. First, by accurately identifying the double-layer passivation structure of the loosely adsorbed contamination layer and the polarized high-resistivity insulating layer, a combination of layered targeted removal and reverse negative voltage depolarization was adopted to completely eliminate the 240V voltage plateau, reducing the plateau duration from the traditional 20s to less than 3s. This also effectively solved problems such as high target resistance, slow voltage ramp-up, and unstable start-up under long standby conditions. Second, a closed-loop adaptive control mechanism based on real-time discharge state feedback ensured that the repair process accurately adapted to the target state under different passivation levels. Third, the entire process was completed in an oxygen-free environment, fundamentally eliminating the risk of excessive leakage defects caused by the introduction of additional oxygen, perfectly meeting the stringent mass production requirements of silicon-based Micro-OLEDs for ultra-low defects and low leakage of ITO anode films. Finally, this process requires no hardware modification to existing mass production equipment, exhibiting strong mass production compatibility. While improving the uniformity of ITO film thickness and device yield, it also achieved complete reset of the target state and high stability of the sputtering process, providing a reliable guarantee for the high-performance fabrication of silicon-based Micro-OLEDs.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a passivation repair method for an ITO sputtering target used in the fabrication of silicon-based Micro-OLEDs, the passivation repair method comprising the following steps: Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorbed contamination layer and a polarized high-resistance insulating layer from the outside to the inside.

[0008] In an oxygen-free environment, the loose adsorbed contamination layer of the ITO target material is removed by physical stripping. Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer to eliminate the polarization charge accumulated in the polarized high-resistivity insulating layer.

[0009] The discharge state feedback parameters of the ITO target are monitored in real time to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target.

[0010] Steady-state sputtering deposition of ITO thin films is performed to form the ITO anode layer of silicon-based Micro-OLEDs.

[0011] The passivation repair method provided by this invention realizes the systematic repair of the passivation state of ITO target material and the closed-loop control of the entire sputtering process. First, by accurately identifying the double-layer passivation structure of the loosely adsorbed contamination layer and the polarized high-resistivity insulating layer, a combination of layered targeted removal and reverse negative voltage depolarization was adopted to completely eliminate the 240V voltage plateau, reducing the plateau duration from the traditional 20s to less than 3s. This also effectively solved problems such as high target resistance, slow voltage ramp-up, and unstable start-up under long standby conditions. Second, a closed-loop adaptive control mechanism based on real-time discharge state feedback ensured that the repair process accurately adapted to the target state under different passivation levels. Third, the entire process was completed in an oxygen-free environment, fundamentally eliminating the risk of excessive leakage defects caused by the introduction of additional oxygen, perfectly meeting the stringent mass production requirements of silicon-based Micro-OLEDs for ultra-low defects and low leakage of ITO anode films. Finally, this process requires no hardware modification to existing mass production equipment, exhibiting strong mass production compatibility. While improving the uniformity of ITO film thickness and device yield, it also achieved complete reset of the target state and high stability of the sputtering process, providing a reliable guarantee for the high-performance fabrication of silicon-based Micro-OLEDs.

[0012] In this invention, a physical peeling method is used to remove the loose adsorbed contamination layer of the ITO target material. This process involves no chemical reaction and no lattice damage, completely removing adsorbed impurities and loose contamination from the target material's surface and restoring its uniform glow-in-the-dark capability. Then, by applying a reverse negative voltage pulsed electric field, the polarized high-resistivity insulating layer is depolarized, eliminating the accumulated polarization charge and the 240V voltage plateau and 20s stagnation anomaly, restoring linear stability to the voltage ramp-up. Therefore, this layered targeted treatment strategy achieves thorough repair through surface cleanliness and deep depolarization, fundamentally solving the standby passivation problem.

[0013] In this invention, by monitoring the discharge state feedback parameters of the ITO target in real time, the pulse sputtering parameters are dynamically adjusted so that the current process conditions are adapted to the real-time passivation state of the ITO target, thereby achieving precise matching of the repair degree, no residue, and no overtreatment.

[0014] This invention strictly eliminates oxygen participation throughout the passivation repair process, preventing problems such as abnormal oxidation, lattice distortion, and defect generation during the activation stage. Oxygen is only introduced after the plasma has reached a completely stable state and the target material has been fully reset to ensure a balance between conductivity and transmittance, enabling steady-state sputtering deposition of the ITO film. This process completely avoids problems such as excessive pixel leakage, uneven light emission, dark spot defects, and premature device aging caused by traditional high-oxygen activation.

[0015] It should be noted that the loose adsorbed contaminant layer refers to the formation of water vapor, carbon impurities, and trace oxides in the air adhering to the surface of the ITO target, causing unstable surface glow and high initial deposited impurities. The polarized high-resistivity insulating layer refers to the dense high-resistivity layer formed by prolonged static electric field and positive charge accumulation, which is the fundamental cause of 240V low voltage clamping, voltage stagnation, and slow ramp-up.

[0016] Preferably, the standby state parameters include any one or a combination of at least two of the following: the time of standby of the machine, the initial impedance of the ITO target, or the ignition voltage response curve.

[0017] The present invention can determine the passivation level based on the time the machine is idle, or it can be determined from the deviation of the initial impedance of the target material and the steady-state voltage after ignition (ignition voltage response curve).

[0018] Preferably, the method for determination includes: If the machine is left idle for less than 15 minutes, such as 12 minutes, 10 minutes or 5 minutes, it is considered to have mild passivation.

[0019] If the machine is left idle for 15 minutes to 1 hour, for example, it could be 30 minutes, 40 minutes, 50 minutes or 1 hour, it is considered to be moderate passivation.

[0020] If the machine is left idle for more than 1 hour, such as 2 hours, 3 hours, 4 hours, 5 hours or 10 hours, it is considered to be severely passivated.

[0021] Preferably, the oxygen-free environment includes a vacuum atmosphere or an inert atmosphere.

[0022] Preferably, the physical stripping method includes the following steps: Inert gas plasma is used for pre-sputtering to physically remove the loose adsorbed contaminant layer on the ITO target.

[0023] The inert gas plasma includes any one or a combination of at least two of argon plasma, krypton plasma, or xenon plasma.

[0024] Preferably, the pre-sputtering process parameters include: The sputtering power is 300W~700W, for example, 300W, 400W, 500W, 600W or 700W, etc.; the sputtering gas pressure is 4mTorr~8mTorr, for example, 4mTorr, 5mTorr, 6mTorr, 7mTorr or 8mTorr, etc.; the inert gas flow rate is 100sccm~800sccm, for example, 100sccm, 150sccm, 300sccm, 500sccm, 700sccm or 800sccm, etc.; the pre-sputtering time is 0.5s~1.5s, for example, 0.5s, 1s or 1.5s, etc.; and the surface temperature of the ITO target is ≤100℃, for example, 80℃, 50℃ or 30℃, etc.

[0025] With the synergistic effect of the above-mentioned parameters, this invention completely removes adsorbed impurities and loose contamination structures from the surface of the target material without chemical reaction or lattice damage, and restores the uniform glowing ability of the target material surface.

[0026] Preferably, the process parameters of the reverse negative voltage pulsed electric field include: The power is 800W~1200W, for example, 800W, 900W, 1000W, 1100W or 1200W, etc.; the reverse negative voltage is 70V~90V, for example, 70V, 80V or 90V, etc.; the reverse pulse duty cycle is 8%~10%, for example, 8%, 9% or 10%, etc.; and the processing time is 1s~4s, for example, 1s, 2s, 3s or 4s, etc.

[0027] With the synergistic cooperation of the above-mentioned parameters, this invention precisely matches the polarization charge energy level and the interface barrier, and directionally neutralizes the steady-state polarization charge accumulated at the interface between the target and the cavity, completely eliminating the voltage clamping effect and the voltage ramp-up stagnation phenomenon, making the entire sputtering ignition, voltage boost, and steady-state discharge process linearly controllable and free from abnormal plateau fluctuations.

[0028] Preferably, the discharge state feedback parameters include any one or a combination of at least two of the following: the discharge impedance feedback signal of the ITO target, the ignition voltage fluctuation signal, or the plasma discharge current signal.

[0029] Preferably, the pulse sputtering parameters include any one or a combination of at least two of the following: pulse duty cycle, pulse voltage, boost slope, pulse duration, or sputtering power.

[0030] This invention employs a closed-loop control method that "real-time monitors the discharge state feedback parameters of the ITO target to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target." This method enables an adaptive process that "stronger repair for heavy passivation and lighter repair for light passivation," significantly improving process consistency and mass production yield.

[0031] Preferably, the passivation repair method includes the following steps: (1) Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorption contamination layer and a polarized high resistance insulation layer from the outside to the inside.

[0032] The standby state parameter is the time the machine is idle. The determination method includes: if the machine's idle time is <15min, it is determined to be mild passivation; if the machine's idle time is 15min~1h, it is determined to be moderate passivation; if the machine's idle time is >1h, it is determined to be severe passivation.

[0033] (2) In an oxygen-free environment, argon plasma is used for pre-sputtering to physically remove the loose adsorbed contaminant layer of the ITO target and restore the uniform glowing ability of the ITO target surface; wherein, the pre-sputtering process parameters include: sputtering power of 300W~700W, sputtering pressure of 4mTorr~8mTorr, argon flow rate of 100sccm~200sccm, pre-sputtering time of 0.5s~1.5s, and surface temperature of ITO target ≤100℃.

[0034] Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, so as to directionally break down and neutralize the polarization charge accumulated in the polarized high-resistivity insulating layer, so that the voltage ramp-up can be restored to linear stability. The process parameters of the reverse negative voltage pulse electric field include: power of 800W~1200W, reverse negative voltage of 70V~90V, reverse pulse duty cycle of 8%~10%, and processing time of 1s~4s.

[0035] (3) Monitor the discharge state feedback parameters of the ITO target in real time to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target; wherein, the discharge state feedback parameters include any one or a combination of at least two of the discharge impedance feedback signal of the ITO target, the ignition voltage fluctuation signal or the plasma discharge current signal; the pulse sputtering parameters include any one or a combination of at least two of the pulse duty cycle, pulse voltage, boost slope, pulse duration or sputtering power.

[0036] (4) Introduce oxygen at a flow rate of 1 sccm to 5 sccm (e.g., 1 sccm, 2 sccm, 3 sccm, 4 sccm or 5 sccm, etc.) and stabilize the voltage at 370 to 380V (e.g., 370V, 375V or 380V, etc.) to perform steady-state sputtering deposition of ITO thin film to form the ITO anode layer of silicon-based Micro-OLED.

[0037] In a second aspect, the present invention provides a silicon-based Micro-OLED, wherein the silicon-based Micro-OLED includes an ITO anode layer, the ITO anode layer being formed by sputtering an ITO target material repaired by the passivation repair method described in the first aspect.

[0038] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0039] Compared with the prior art, the present invention has the following beneficial effects: The passivation repair method provided by this invention realizes the systematic repair of the passivation state of ITO target material and the closed-loop control of the entire sputtering process. First, by accurately identifying the double-layer passivation structure of the loosely adsorbed contamination layer and the polarized high-resistivity insulating layer, a combination of layered targeted removal and reverse negative voltage depolarization was used to completely eliminate the 240V voltage plateau, reducing the plateau duration from the traditional 20s to less than 3s. This also effectively solved problems such as high target resistance, slow voltage ramp-up, and unstable start-up under long standby conditions. Second, a closed-loop adaptive control mechanism based on real-time discharge state feedback ensured that the repair process accurately adapted to the target state under different passivation levels. Third, the entire process was completed in an oxygen-free environment, fundamentally eliminating the risk of excessive leakage defects caused by the introduction of additional oxygen, perfectly meeting the stringent mass production requirements of silicon-based Micro-OLEDs for ultra-low defects and low leakage of ITO anode films. Finally, this process requires no hardware modification to existing mass production equipment, exhibiting strong mass production compatibility. While improving the uniformity of ITO film thickness and device yield, it also achieved complete reset of the target state and high stability of the sputtering process, providing a reliable guarantee for the high-performance fabrication of silicon-based Micro-OLEDs. Attached Figure Description

[0040] Figure 1 This is a process flow diagram provided in a specific embodiment of the present invention. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0042] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0043] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0044] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0045] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0046] In one specific embodiment, the present invention provides a passivation repair method for ITO sputtering targets used in the fabrication of silicon-based Micro-OLEDs, the process flow diagram of which is shown below. Figure 1As shown, the passivation repair method includes the following steps: (1) Obtain the standby time of the ITO target material on the machine and perform long standby passivation determination: If the machine is idle for less than 15 minutes, it is considered to have mild passivation. The process then determines whether it is in mass production mode. If it is in mass production mode, the passivation repair process will begin. If it is not in mass production mode, the process will end.

[0047] If the machine is left idle for ≥15 minutes, it will proceed to the subsequent passivation repair process.

[0048] (2) In an oxygen-free environment, argon plasma is used for pre-sputtering to physically remove the loose adsorbed contamination layer of the ITO target material and restore the uniform glowing ability of the ITO target material surface. Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, so as to directionally break down and neutralize the polarization charge accumulated in the polarized high-resistivity insulating layer, thereby restoring the voltage ramp-up to linear stability.

[0049] (3) Monitor the discharge state feedback parameters of the ITO target in real time to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target.

[0050] (4) Introduce oxygen to enter the low-oxygen steady-state transition phase, and then determine the steady state: If the steady-state determination is qualified, then it is determined again whether it is in mass production mode. If it is in mass production mode, then it enters mass production; if it is not in mass production mode, then the process ends. If the steady-state determination fails, return to step (2).

[0051] In another specific embodiment, the present invention provides the following specific examples.

[0052] It should be noted that the equipment parameters of the ITO preparation equipment used in the following embodiments include: rated power 3000W, steady-state voltage 375V, pulse frequency 100kHz, oxygen flow rate ≤5sccm, and argon gas using a constant flow rate from mass production.

[0053] Example 1 This embodiment provides a passivation repair method for ITO sputtering targets used in silicon-based Micro-OLED fabrication, the passivation repair method comprising the following steps: (1) Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorption contamination layer and a polarized high resistance insulation layer from the outside to the inside.

[0054] The standby status parameter is the time the machine is idle. If the machine is idle for 12 minutes, it is considered to be slightly passivated and there is a risk of 240V voltage clamping.

[0055] (2) In a vacuum environment, argon gas with a flow rate of 100 sccm is introduced, and the generated argon plasma is used for pre-sputtering to physically remove the loose adsorbed contamination layer of the ITO target and restore the uniform glowing ability of the ITO target surface; wherein, the pre-sputtering process parameters include: sputtering power of 400W, sputtering pressure of 5mTorr, pre-sputtering time of 0.5s, and surface temperature of ITO target of 25℃.

[0056] Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, so as to directionally break down and neutralize the polarization charge accumulated in the polarized high-resistivity insulating layer, so that the voltage ramp-up can be restored to linear stability; wherein, the process parameters of the reverse negative voltage pulse electric field include: power of 800W, reverse negative voltage of 70V, reverse pulse duty cycle of 8%, and processing time of 1s.

[0057] (3) Turn off the reverse negative pressure, and then adjust the pulse duty cycle from 50% to 70% continuously. The pulse voltage rises steadily, the voltage ramp rate is 100V / s, the pulse duration is 3s, and the sputtering power rises to 3000W simultaneously.

[0058] (4) Introduce oxygen at a flow rate of 2 sccm, stabilize the voltage at 370V, and after the steady state is determined to be qualified, determine the mass production mode and perform steady-state sputtering deposition of ITO thin film to form the ITO anode layer of silicon-based Micro-OLED.

[0059] As can be seen from the results of Example 1, the original 20s voltage plateau was completely eliminated, and the stagnation time was <1s; there was no arc light or voltage oscillation throughout the process; the sheet resistance uniformity of the ITO film (obtained by a four-probe resistance tester) was ≤2.5%, and the leakage current index of the Micro-OLED pixel was normal.

[0060] Example 2 This embodiment provides a passivation repair method for ITO sputtering targets used in silicon-based Micro-OLED fabrication, the passivation repair method comprising the following steps: (1) Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorption contamination layer and a polarized high resistance insulation layer from the outside to the inside.

[0061] The standby state parameter is the time the machine is idle. If the machine is idle for 30 minutes, it is judged to be moderate passivation, and there is a predicted risk of 240V voltage clamping.

[0062] (2) In an oxygen-free environment, argon gas with a flow rate of 150 sccm is introduced, and the generated argon plasma is used for pre-sputtering to physically remove the loose adsorbed contamination layer of the ITO target and restore the uniform glowing ability of the ITO target surface; wherein, the pre-sputtering process parameters include: sputtering power of 500W, sputtering pressure of 6mTorr, pre-sputtering time of 1s, and surface temperature of the ITO target of 30℃.

[0063] Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, so as to directionally break down and neutralize the polarization charge accumulated in the polarized high-resistivity insulating layer, so that the voltage ramp-up can be restored to linear stability; wherein, the process parameters of the reverse negative voltage pulse electric field include: power of 900W, reverse negative voltage of 75V, reverse pulse duty cycle of 9%, and processing time of 3s.

[0064] (3) Turn off the reverse negative pressure, and then adjust the pulse duty cycle from 50% to 70% continuously. The pulse voltage rises steadily, the voltage ramp rate is 75V / s, the pulse duration is 4s, and the sputtering power rises to 3000W simultaneously.

[0065] (4) Introduce oxygen at a flow rate of 2 sccm, stabilize the voltage at 375V, and after the steady state is determined to be qualified, determine the mass production mode and perform steady-state sputtering deposition of ITO thin film to form the ITO anode layer of silicon-based Micro-OLED.

[0066] The results of Example 2 show that the plasma state is stable during steady-state sputtering deposition, with no voltage plateau or micro-arc discharge, and the electrical properties and uniformity of the ITO film are consistent with those of normal production batches.

[0067] Example 3 This embodiment provides a passivation repair method for ITO sputtering targets used in silicon-based Micro-OLED fabrication, the passivation repair method comprising the following steps: (1) Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorption contamination layer and a polarized high resistance insulation layer from the outside to the inside.

[0068] The standby status parameter refers to the time the machine is idle. If the machine is idle for 5 hours, it is considered to be severely passivated, and there is a predicted risk of 240V voltage clamping.

[0069] (2) In an oxygen-free environment, argon gas with a flow rate of 200 sccm is introduced, and the generated argon plasma is used for pre-sputtering to physically remove the loose adsorbed contamination layer of the ITO target and restore the uniform glowing ability of the ITO target surface; wherein, the pre-sputtering process parameters include: sputtering power of 600W, sputtering pressure of 7mTorr, pre-sputtering time of 1.5s, and surface temperature of ITO target of 35℃.

[0070] Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, so as to directionally break down and neutralize the polarization charge accumulated in the polarized high-resistivity insulating layer, so that the voltage ramp-up can be restored to linear stability; wherein, the process parameters of the reverse negative voltage pulse electric field include: power of 1000W, reverse negative voltage of 80V, reverse pulse duty cycle of 10%, and processing time of 4s.

[0071] (3) Turn off the reverse negative pressure, and then adjust the pulse duty cycle from 45% to 70% continuously. The pulse voltage rises steadily, the voltage ramp rate is 100V / s, the pulse duration is 3s, and the sputtering power rises to 3000W simultaneously.

[0072] (4) Introduce oxygen at a flow rate of 2 sccm, stabilize the voltage at 370V, and after the steady state is determined to be qualified, determine the mass production mode and perform steady-state sputtering deposition of ITO thin film to form the ITO anode layer of silicon-based Micro-OLED.

[0073] As can be seen from the results of Example 3, the high resistance problem caused by long resting time has been completely eliminated, the ramp-up process is smooth, and the device yield is no different from that of normal production.

[0074] Comparative Example 1 The difference between this comparative example and Example 1 is that step (1) is omitted.

[0075] The remaining passivation repair methods and parameters are consistent with those in Example 1.

[0076] Comparative Example 2 The difference between this comparative example and Example 1 is that the pre-sputtering process in step (2) is not performed.

[0077] The remaining passivation repair methods and parameters are consistent with those in Example 1.

[0078] Comparative Example 3 The difference between this comparative example and Example 1 is that the depolarization process of the polarized high-resistivity insulating layer in step (2) is not performed.

[0079] The remaining passivation repair methods and parameters are consistent with those in Example 1.

[0080] Comparative Example 4 The difference between this comparative example and Example 1 is that step (3) is omitted.

[0081] The remaining passivation repair methods and parameters are consistent with those in Example 1.

[0082] As can be seen from the comparison between Example 1 and Comparative Example 1, if the standby passivation level is not determined in step (1), the risk of 240V voltage clamping cannot be predicted in advance based on the machine's resting time, and the complete repair process logic cannot be matched and adapted. When the machine's resting time exceeds 12 minutes and mild passivation occurs, the repair process has no advance warning control, the degree of charge and impurity accumulation in the passivation layer is unknown, and the problem of insufficient adaptability of the repair process is likely to occur. The voltage ramping will reappear with a significant plateau, random arc discharge will occur, the uniformity of ITO film sheet resistance will deteriorate, some silicon-based Micro-OLED pixels will have excessive leakage current, and the product yield will fluctuate greatly.

[0083] As can be seen from the comparison between Example 1 and Comparative Example 2, if the pre-sputtering process in step (2) is not performed, the loose adsorbed contaminant layer on the outer surface of the target material cannot be physically stripped by argon ions. Surface water vapor, organic impurities in the chamber, and particle residues will destroy the uniformity of the target material's overall ignition. The bias voltage in the ignition area is uneven, the voltage fluctuates frequently and slightly, the sheet resistance deviation of the film increases significantly, and the uniformity is much higher than 2.5%. Impurities are deposited on the silicon-based wafer ITO anode with sputtering, causing pixel interface defects, and the number of leakage defects in Micro-OLED increases significantly.

[0084] As can be seen from the comparison between Example 1 and Comparative Example 3, if the depolarization treatment process of the polarized high-resistivity insulating layer in step (2) is not carried out, the polarization charge accumulated in the inner polarized insulating layer of the target material cannot be neutralized or broken down, the risk of 240V voltage clamping cannot be eliminated at all, and the voltage ramp-up will have a stagnation plateau lasting more than ten seconds; there will be continuous electric field distortion caused by charge accumulation, and the sputtering process will frequently generate arcing, burn the target material and cause wafer point defects; the voltage will continue to fluctuate violently, and the electrical stability of the final ITO anode layer will be extremely poor, the pixel leakage will seriously exceed the standard, and it will not meet the requirements of Micro-OLED mass production.

[0085] As can be seen from the comparison between Example 1 and Comparative Example 4, if the gradient control of continuous duty cycle increase and synchronous power increase in step (3) is not performed, direct high-power sputtering will form an instantaneous strong electric field impact on the repaired target surface, which will induce secondary polarization of the surface charge again; the voltage rise process will result in large jumps, short-term voltage plateaus, and occasional instantaneous arcs; the activation of the target conductive channel will be uneven, the uniformity of the film's lateral sheet resistance will deteriorate, the pixel leakage index will show poor dispersion, the process window will narrow, and the mass production stability will decrease significantly.

[0086] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A passivation repair method for ITO sputtering targets used in silicon-based Micro-OLED fabrication, characterized in that, The passivation repair method includes the following steps: The standby state parameters of the ITO target are obtained, and the passivation level of the ITO target surface is determined based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target due to static placement. The passivation layer includes a loose adsorbed contamination layer and a polarized high-resistance insulating layer from the outside to the inside. In an oxygen-free environment, the loose adsorbed contamination layer of the ITO target is removed by physical stripping. Then, a reverse negative pressure pulsed electric field is applied to depolarize the polarized high-resistivity insulating layer, thereby eliminating the accumulated polarization charge in the polarized high-resistivity insulating layer. The physical stripping method includes the following steps: pre-sputtering with inert gas plasma to physically remove the loose adsorbed contamination layer of the ITO target. The pre-sputtering process parameters include: sputtering power of 300W~700W, sputtering pressure of 4mTorr~8mTorr, inert gas flow rate of 100sccm~200sccm, pre-sputtering time of 0.5s~1.5s, and surface temperature of the ITO target ≤100℃. The reverse negative pressure pulsed electric field process parameters include: power of 800W~1200W, reverse negative pressure of 70~90V, reverse pulse duty cycle of 8%~10%, and processing time of 1s~4s. The discharge state feedback parameters of the ITO target are monitored in real time to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target. Steady-state sputtering deposition of ITO thin film is performed to form the ITO anode layer of silicon-based Micro-OLED; The standby state parameters include any one or a combination of at least two of the following: the machine's standby time, the initial impedance of the ITO target, or the ignition voltage response curve; the determination method includes: If the machine is left idle for less than 15 minutes, it is considered to be slightly passivated. If the machine is left idle for 15 minutes to 1 hour, it is considered to have moderate passivation. If the machine is left idle for more than 1 hour, it is considered to be severely passivated.

2. The passivation repair method according to claim 1, characterized in that, The oxygen-free environment is a vacuum atmosphere or an inert atmosphere.

3. The passivation repair method according to claim 1, characterized in that, The inert gas plasma includes any one or a combination of at least two of argon plasma, krypton plasma, or xenon plasma.

4. The passivation repair method according to claim 1, characterized in that, The discharge state feedback parameters include any one or a combination of at least two of the following: the discharge impedance feedback signal of the ITO target, the ignition voltage fluctuation signal, or the plasma discharge current signal. And / or, the pulse sputtering parameters include any one or a combination of at least two of the following: pulse duty cycle, pulse voltage, boost slope, pulse duration, or sputtering power.

5. The passivation repair method according to claim 1, characterized in that, The passivation repair method includes the following steps: (1) Obtain the standby state parameters of the ITO target material, and determine the passivation level of the ITO target material surface based on the standby state parameters. The passivation level is used to characterize the passivation degree of the passivation layer formed by the ITO target material due to static placement. The passivation layer includes a loose adsorbed contamination layer and a polarized high-resistance insulating layer from the outside to the inside. The standby state parameter is the time the machine is idle. The determination method includes: if the machine's idle time is <15min, it is determined to be mild passivation; if the machine's idle time is 15min~1h, it is determined to be moderate passivation; if the machine's idle time is >1h, it is determined to be severe passivation. (2) In an oxygen-free environment, argon plasma is used for pre-sputtering to physically remove the loose adsorbed contaminant layer of the ITO target and restore the uniform glowing ability of the ITO target surface; wherein, the pre-sputtering process parameters include: sputtering power of 300W~700W, sputtering pressure of 4mTorr~8mTorr, argon flow rate of 100sccm~200sccm, pre-sputtering time of 0.5s~1.5s, and surface temperature of the ITO target ≤100℃; Then, a reverse negative voltage pulse electric field is applied to depolarize the polarized high-resistivity insulating layer, thereby directionally breaking down and neutralizing the polarization charge accumulated in the polarized high-resistivity insulating layer, so that the voltage ramp-up can be restored to linear stability. The process parameters of the reverse negative voltage pulse electric field include: power of 800W~1200W, reverse negative voltage of 70V~90V, reverse pulse duty cycle of 8%~10%, and processing time of 1s~4s. (3) Monitor the discharge state feedback parameters of the ITO target in real time to dynamically adjust the pulse sputtering parameters so that the current process conditions are adapted to the real-time passivation state of the ITO target; wherein, the discharge state feedback parameters include any one or a combination of at least two of the discharge impedance feedback signal of the ITO target, the ignition voltage fluctuation signal or the plasma discharge current signal; the pulse sputtering parameters include any one or a combination of at least two of the pulse duty cycle, pulse voltage, boost slope, pulse duration or sputtering power; (4) Introduce oxygen at a flow rate of 1 sccm to 5 sccm and stabilize the voltage at 370V to 380V to perform steady-state sputtering deposition of ITO thin film to form the ITO anode layer of silicon-based Micro-OLED.

6. A silicon-based Micro-OLED, characterized in that, The silicon-based Micro-OLED includes an ITO anode layer, which is formed by sputtering an ITO target material repaired by the passivation repair method according to any one of claims 1-5.

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