A layered alloy MEMS vertical needle simulation design method and device

Abstract

The application discloses a layered alloy MEMS vertical needle simulation design method and device, and belongs to the technical field of micro-electro-mechanical systems. It aims to solve the problems of traditional methods, which can only optimize the probe shape, cannot directly adjust the layered parameters, and have long design and production cycles and high costs. The steps include: establishing a preliminary 3D model of a vertical probe and layering along the needle thickness, assigning material parameters to each layer and making binding settings for adjacent layers; adding lower guide plates and needle tip / needle tail contact cover plates in the simulation environment, fixing the guide plate and needle tail cover plate, applying displacement load to the needle tip cover plate, and simulating to obtain BCF, stress and deformation data; based on the data, adjusting the shape and layered parameter optimization scheme, and then using MEMS technology to produce a physical object, and comparing the simulation data for iteration. The method realizes full-dimensional optimization, shortens the cycle, reduces the cost, and helps to improve the performance of the probe.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical systems (MEMS) technology, and in particular to a method and apparatus for simulating and designing layered alloy MEMS vertical pins. Background Technology

[0002] In fields such as semiconductor testing and microelectromechanical systems (MEMS) signal transmission, MEMS vertical probes are core contact elements, and their performance directly determines the testing accuracy, signal stability, and service life. These probes need to meet multiple requirements simultaneously: they must have good conductivity to reduce signal loss, sufficient hardness and fatigue resistance to cope with high-frequency insertion and removal, and in some scenarios, they also need to be adaptable to complex working conditions such as temperature and humidity. Traditional single materials can hardly meet these comprehensive performance requirements.

[0003] Current MEMS vertical probe design and simulation often employ an "overall structural assumption." This involves first measuring the force values ​​using a physical probe to infer the overall material parameters (such as elastic modulus), and then optimizing only the probe's width, bending radius, and other external dimensions based on these parameters. The manufacturing process requires repeated cycles of "process adjustment - physical manufacturing - performance testing." If changes to the material composition or layered structure are desired, the manufacturing process must be restructured first, followed by a complete iteration of the entire process.

[0004] This traditional approach has some problems. On the one hand, it cannot directly simulate and optimize layering parameters (such as the number of layers, layer thickness, and material combination), which limits the improvement of probe performance. On the other hand, repeated process trial and error and physical iteration significantly prolong the cycle from design to mass production, while increasing R&D and manufacturing costs, making it difficult to meet the current semiconductor industry's rapid R&D needs for customized, high-precision probes. Summary of the Invention

[0005] This application provides a method and apparatus for simulating and designing layered alloy MEMS vertical pins. The technical solution is as follows: On the one hand, a simulation design method for layered alloy MEMS vertical pins is provided, the method comprising: A preliminary 3D model of the vertical probe was created, and the 3D model was layered along the probe thickness direction. Each layer is assigned the physical property parameters of the corresponding material, and adjacent layers are bound together. The binding settings match the alloy characteristics of the layered structure in the MEMS layered manufacturing process. Based on the 3D model and actual working conditions, upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate are added to the simulation environment. The upper and lower guide plates and the needle tail contact cover plate are set as fixed constraints, and a preset displacement load is applied to the needle tip contact cover plate to perform single needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of a single needle. Based on the balanced contact force BCF, stress, and deformation data, the external dimensions and layering parameters of the vertical needle are adjusted using multiple parameters, and optimized through parametric simulation settings to obtain a layering scheme and external structure that meet performance requirements. A physical probe is produced using MEMS technology based on the layered scheme and external structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probe are compared with the simulation data to perform simulation consistency iteration.

[0006] Optionally, the layering process can be any one or a combination of at least two of the following: symmetrical layering, asymmetrical layering, gradient layering, and linear layering. Furthermore, the needle tip area of ​​the 3D model is designed with a metal layer that has a higher hardness than the corresponding layer of the needle body. The transition area between the metal layer and the corresponding layer of the needle body is provided with a reinforcing structure at the connection point. The material of the metal layer is rhodium. The number of layers obtained by the layering process is 3 to 10, and the thickness of each layer is independent, ranging from 2 μm to 10 μm.

[0007] Optionally, the materials in each layer are two materials alternately distributed, wherein the two materials are selected from any two of palladium, cobalt, nickel, copper, and gold; or, The first and last layers of the 3D model are made of non-metallic material, specifically PI material, and the thickness of each layer is 2μm to 5μm; or, At least one layer of material is graphene.

[0008] Optionally, the contact settings for the single-needle stress simulation are as follows: the adjacent layers are bonded together, and the probe and the opening surfaces of the upper and lower guide plates, the probe and the needle tip contact cover plate, and the probe and the needle tail contact cover plate are all in frictional contact. The friction coefficient of the frictional contact is set to 0.1, the contact stiffness is set to 0.1, and the damping coefficient is set to 0.01. Furthermore, the large deformation calculation is enabled when solving the single-needle stress simulation.

[0009] Optionally, when assigning physical property parameters of the corresponding materials to each layer, the thermal expansion coefficient, elastic modulus, Poisson's ratio, yield strength, thermal conductivity and resistivity of each material are set separately according to the temperature range of -40℃ to 175℃. The single-needle force simulation also includes thermodynamic coupling simulation, or current withstand simulation by applying voltage to both ends of the probe to obtain thermal expansion deformation data and equilibrium contact force BCF of the probe under different currents.

[0010] Optionally, the external dimensional parameters include needle arm width, needle arm thickness, bending radius, and bending position; the layering parameters include the number of layers and the thickness of each layer; the parameterized simulation settings are achieved by parameterizing the layered cross-sections using simulation software, which automatically calculates and obtains the optimal layer thickness scheme.

[0011] Optionally, the number of upper and lower guide plates is 2 to 4 layers, and the upper and lower guide plates are respectively located in the straight areas at both ends of the probe; the single needle force simulation also includes simulation optimization of the opening size and opening chamfer of the upper and lower guide plates.

[0012] Optionally, the method further includes: A 1μm thick coating is applied to the corresponding layer of the needle body surface of the 3D model. The coating is an insulating coating or a high-temperature alloy coating. The insulating coating is made of PI, and the high-temperature alloy coating is made of TiC-Ni. The contact surface between the coating and the corresponding layer of the needle body is designed to be bonded.

[0013] Optionally, the simulation consistency iteration includes: If there is a difference between the measured data and the simulation data of the physical probe, adjust the material physical property parameters, layer thickness or vertical needle shape parameters of the corresponding layer based on the difference, and re-perform single needle force simulation and parameter optimization. Until the deviation between the measured data and the simulation data is less than the preset threshold.

[0014] On the other hand, a layered alloy MEMS vertical pin simulation design device is provided, the device comprising: The model building module is used to build a 3D model of the initial vertical probe and to perform layering processing on the 3D model along the probe thickness direction; The parameter setting module is used to assign physical property parameters of the corresponding materials to each layer and to set the binding of adjacent layers. The binding settings match the alloy characteristics of the layered structure in the MEMS layered manufacturing process. The simulation operation module is used to add upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate to the simulation environment based on the 3D model and actual working conditions. The single-needle simulation module is used to set the upper and lower guide plates and the needle tail contact cover plate as fixed constraints, and apply a preset displacement load to the needle tip contact cover plate to perform single-needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of the single needle. The parameter adjustment module is used to adjust the external dimensions and layering parameters of the vertical needle based on the balanced contact force BCF, stress and deformation data, and optimize them through parametric simulation settings to obtain a layering scheme and external structure that meets performance requirements. The simulation testing module is used to produce physical probes using MEMS technology according to the layered scheme and external structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probes are compared with the simulation data to perform simulation consistency iteration.

[0015] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the computer program, which is loaded and executed by a processor to implement the layered alloy MEMS vertical needle simulation design method as described above.

[0016] This application discloses a simulation design method for layered alloy MEMS vertical probes, aiming to solve the problems of traditional methods that can only optimize the probe shape but cannot directly adjust the layering parameters, and are characterized by long design and production cycles and high costs. The steps include: establishing an initial 3D model of the vertical probe and layering it along the probe thickness; assigning material parameters to each layer and binding adjacent layers (adapting to MEMS layered manufacturing processes); adding upper and lower guide plates and a tip / tail contact cover plate in the simulation environment; fixing the guide plate and tail cover plate; applying displacement loads to the tip cover plate; and simulating to obtain BCF, stress, and deformation data; adjusting the shape and layering parameter optimization scheme based on the data; then producing a physical prototype using MEMS technology; and comparing the simulation data for iteration. This method achieves full-dimensional optimization, shortens the cycle, reduces costs, and contributes to improving probe performance. Attached Figure Description

[0017] Figure 1 A flowchart illustrating a simulation design method for a layered alloy MEMS vertical pin is shown. Figure 2 This diagram illustrates a MEMS needle-shaped design. Figure 3 This diagram illustrates a layered structure of MEMS needles. Figure 4 This diagram illustrates a MEMS thermal simulation. Figure 5 This diagram illustrates a MEMS application structure. Figure 6 This diagram illustrates a MEMS mechanical simulation. Figure 7 This diagram illustrates a MEMS OD component. Figure 8 This diagram illustrates a MEMS stress structure. Figure 9 A cross-sectional view of a MEMS needle-side structure is shown. Figure 10 This diagram illustrates the distribution of a copper-rhodium material in MEMS. Figure 11 This diagram illustrates a layered deformation pattern in MEMS. Figure 12 This diagram illustrates a simulation of layered stress in MEMS. Figure 13 A diagram illustrating a cantilevered 3D MEMS structure is shown. Figure 14 A schematic diagram of a MEMS surface coating is shown. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0019] In this article, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0020] Example 1 like Figure 1 The diagram shows a flowchart of a simulation design method for a layered alloy MEMS vertical pin. This application provides a simulation design method for a layered alloy MEMS vertical pin, the method comprising: Step 101: Establish a 3D model of the initial vertical probe and perform layering processing on the 3D model along the probe thickness direction.

[0021] like Figure 2 The diagram shows a schematic of a MEMS vertical needle. The MEMS (Micro Electro Mechanical System) vertical needle mainly includes a needle tip, a needle arm, a bending section, and a needle tail connection area. The needle arm is used to provide overall elastic deformation capability, the bending section is used to realize elastic deformation compensation in the vertical direction, the needle tip is used to form electrical contact with the tested pad or contact end, and the needle tail is used to connect with the signal transmission structure.

[0022] This step is the foundational modeling stage of the entire simulation design methodology. Its core lies in transforming the structural characteristics of the MEMS vertical needle into a simulable digital model through 3D modeling and layering. The diversity of layering methods (combinations of symmetrical, asymmetrical, and gradient layers) provides flexibility to adapt to different performance requirements—for example, symmetrical layering ensures uniform stress distribution, while asymmetrical layering can specifically enhance the performance of a particular side. The use of higher-hardness metal layers such as rhodium in the needle tip area directly solves the problem of easy tip wear during high-frequency contact, while the reinforcing structure in the transition area (such as rounded corners) avoids stress concentration when connecting materials of different hardness. The range of 3 to 10 layers and the thickness range of 2 μm to 10 μm considers both the processing precision of MEMS technology (too thin or too many layers would reduce yield) and the ability to achieve a balance of "hardness-conductivity-fatigue resistance" that is difficult to achieve with a single material through multi-layer combinations, laying the structural foundation for subsequent material parameter assignment and simulation optimization.

[0023] like Figure 3 The diagram shown is a schematic of the layered structure of a MEMS vertical needle.

[0024] In this embodiment, the vertical needle is divided into multiple functional layers along its thickness direction, and each layer can be made of different materials or have different thicknesses. Through the layered structure design, a combination of different material properties can be achieved. For example, a high-hardness layer is used to improve wear resistance, and a high-conductivity layer is used to improve signal transmission efficiency, thereby improving electrical performance while ensuring mechanical performance.

[0025] The above structural design enables the MEMS vertical needle to generate stable elastic deformation and maintain stable contact performance during the pressure process.

[0026] Step 102: Assign physical property parameters of the corresponding material to each layer, and set up binding between adjacent layers. The binding settings match the layered structure alloy characteristics of the MEMS layered manufacturing process.

[0027] By assigning material parameters to the layers and setting binding relationships, the digital model acquires realistic physical properties. The material parameters of each layer (such as elastic modulus and coefficient of thermal expansion) directly determine the accuracy of the simulation results, while "binding settings matching MEMS layered manufacturing processes" is the core. For example, it simulates the metallurgical bonding characteristics of adjacent metal layers in electroplating processes, or the interfacial bonding state between non-metallic and metallic layers in deposition processes, avoiding the interlayer interaction distortion problem caused by the "overall material assumption" in traditional simulations. This setting ensures that the simulation model can realistically reflect the actual mechanical behavior of the layered alloy, providing a reliable physical basis for subsequent stress analysis.

[0028] like Figure 9 The image shows a schematic cross-sectional view of the MEMS vertical needle-side structure.

[0029] The cross-sectional structure allows for a clear observation of the bonding state between the layers of material. In this embodiment, adjacent layers are bonded together to simulate the metallurgical bonding interface formed in MEMS electroplating or deposition processes, thereby ensuring that the simulation model accurately reflects the actual manufactured structure.

[0030] Step 103: Based on the 3D model and actual working conditions, add upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate to the simulation environment.

[0031] The upper and lower guide plates are the mounting and limiting structures for the MEMS vertical probe during operation, while the probe tip / tail contact cover simulates the contact scenario between the probe and the device under test (DUT) and signal terminals. By introducing these supporting structures, the constraints (such as the guide plate's limiting effect on the probe body) and contact states (such as the interaction between the probe tip and the DUT) of the probe in actual operation can be simulated more realistically. This avoids deviations between simulation results and actual working conditions caused by ignoring the supporting structures (for example, the size of the guide plate opening will affect the lateral constraint when the probe bends, thus changing the stress distribution), ensuring the integrity of the simulation scenario.

[0032] Step 104: Set the upper and lower guide plates and the needle tail contact cover plate as fixed constraints, and apply a preset displacement load to the needle tip contact cover plate to perform single needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of a single needle.

[0033] By setting constraints, applying loads, and calculating key indicators, a quantitative evaluation of probe performance is achieved. The upper and lower guide plates and the probe tail cover are fixed to simulate the fixed state of the probe during actual installation. A preset displacement load is applied to the probe tip contact cover to recreate the probe's working process from contact to deformation. The obtained equilibrium contact force (BCF) reflects the probe's contact stability, stress data reveals structural weaknesses (such as bending sections), and deformation data is related to the probe's stroke accuracy. In particular, the "large deformation calculation" implicit in the simulation (addressing the probe's large deflection characteristics) ensures the accuracy of results under nonlinear deformation, providing a quantifiable evaluation basis for subsequent optimization.

[0034] like Figure 8 The figure shows a schematic diagram of the force structure of a MEMS vertical needle in a simulation environment.

[0035] In this structure, the probe is constrained at both ends by upper and lower guide plates, the tail area is set as a fixed constraint, and the tip of the probe is subjected to displacement load through the contact cover plate, thereby simulating the actual contact deformation state of the probe during the test.

[0036] During the simulation, by applying a preset displacement to the needle tip, the balanced contact force (BCF), stress distribution, and overall deformation of the probe during the compression process can be obtained.

[0037] like Figure 12 The figure shown is a schematic diagram of the layered stress simulation of a MEMS vertical needle.

[0038] Finite element analysis (FEM) can be used to obtain the stress distribution in different regions of the probe, with the bending section typically being a stress concentration area. By analyzing the stress distribution, the layered structure, material composition, and shape parameters can be optimized to ensure that the maximum stress is below the material's yield strength, thereby guaranteeing the reliability of the probe during long-term operation.

[0039] Step 105: Based on the balanced contact force BCF, stress and deformation data, adjust the external dimensions and layering parameters of the vertical needle using multiple parameters, and optimize them through parametric simulation settings to obtain a layering scheme and external structure that meet the performance requirements.

[0040] By employing multi-parameter adjustment and parametric simulation, the limitations of traditional single-dimensional optimization are overcome. Dimensional parameters (such as needle arm width and bending radius) directly affect overall mechanical properties, while layering parameters (such as the number of layers and the thickness of each layer) determine the synergistic effect of the material combination. Adjusting these parameters in tandem can achieve performance optimization where "1+1>2" (for example, reducing the needle arm width while increasing the thickness of the high-hardness layer can reduce overall mass while maintaining hardness). Parametric simulation settings (such as automatically generating multiple parameter combinations via scripts) significantly improve optimization efficiency, enabling rapid selection of solutions that meet comprehensive requirements such as "BCF stability, stress below yield strength, and deformation matching the stroke," thus solving the problems of low efficiency and incomplete optimization associated with traditional manual trial-and-error methods.

[0041] like Figure 11 The figure shows a schematic diagram of the layered deformation of a MEMS vertical needle under stress conditions.

[0042] After applying displacement load, each layer of the structure undergoes varying degrees of deformation, with the bending region exhibiting the greatest deformation. By analyzing the deformation of the layered structure, the thickness of each layer and the material composition can be further optimized, thereby improving the overall structural stability and service life of the probe.

[0043] Step 106: Using MEMS technology, a physical probe is produced according to the layering scheme and shape structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probe are compared with the simulation data to perform simulation consistency iteration.

[0044] Iterative simulation testing enhances design reliability. Physical probes are manufactured using MEMS technology to verify the manufacturability of the simulation scheme. Comparing measured and simulated data reveals deviations between model assumptions and actual processes (e.g., differences between measured and simulated material parameters). By correcting model parameters (e.g., adjusting the elastic modulus of a material layer) or fine-tuning the design (e.g., modifying layer thickness), the deviation between simulation and measurement is brought into convergence. This ensures both the practical feasibility of the design and optimizes the prediction accuracy of the simulation model, providing a reusable model foundation for subsequent product designs and significantly shortening the development cycle.

[0045] In practical applications, this layered alloy MEMS vertical needle simulation design method can be implemented according to the following steps.

[0046] First, a preliminary 3D model of the vertical probe was created using SolidWorks. The model included a needle arm (500 μm long, 50 μm wide), a curved section (30 μm radius), and a needle tip (30° cone angle), and was evenly divided into 5 layers along the needle thickness direction (total thickness 20 μm). Next, material parameters were assigned to each layer—palladium (elastic modulus 120 GPa, Poisson's ratio 0.38) for layers 1, 3, and 5, and copper (elastic modulus 110 GPa, Poisson's ratio 0.34) for layers 2 and 4. Adjacent layers were connected using ANSYS's "binding contact" function to simulate the interlayer metallurgical bonding characteristics in MEMS electroplating processes. Subsequently, upper and lower guide plates (20 μm thick, 60 μm opening diameter) and a contact cover were added to the simulation environment, and the upper and lower guide plates were fixed to the needle tail cover. A displacement load of 0.5 mm / s was applied to the needle tip cover plate until the maximum stroke of 100 μm was reached. Large deformation calculation was then initiated, and the single needle equilibrium contact force (BCF) was found to be 80 mN, with a maximum stress of 250 MPa (located in the bending section). Based on this result, the needle arm width (45~55 μm) and layer thickness (3~5 μm) were adjusted through the parameterization module. After 10 iterations, the optimal solution was determined: a needle arm width of 52 μm and a layer thickness of 4 μm. At this point, the BCF stabilized in the range of 75~85 mN, and the stress decreased to 220 MPa. Finally, a physical probe was produced using MEMS electroplating technology. The measured BCF was 78 mN, which deviated from the simulation value by 3.8%. By correcting the elastic modulus parameter of the copper layer (from 110 GPa to 108 GPa), the deviation of the secondary simulation was reduced to 1.2%.

[0047] This embodiment incorporates the layered material parameters and structural parameters into the simulation optimization simultaneously, breaking through the limitation of traditional methods that can only optimize the shape. It controls the deviation between the simulation results and the actual object to within 5%, reduces the number of iterations by 60% compared to the traditional "trial and error method", and achieves the composite performance of "high conductivity (copper layer) + high hardness (palladium layer)" of the probe, meeting the requirements for contact stability and lifespan in semiconductor testing.

[0048] Example 2 In practical applications of MEMS vertical probes, the core performance requirements of the probes vary significantly across different scenarios. For example, conventional semiconductor testing requires both "high conductivity" and "wear resistance and hardness," high-voltage testing scenarios require additional "insulation and short-circuit protection" capabilities, and high-frequency signal transmission scenarios have an extreme requirement for "ultra-low signal loss." Traditional single-metal materials (such as pure copper, which has excellent conductivity but low hardness, and pure palladium, which has high hardness but weak conductivity) cannot simultaneously meet multi-dimensional performance requirements. Therefore, based on the flexibility of the layered structure, the following three optional layered material schemes are designed to provide customized solutions for different core needs, as detailed below.

[0049] Option 1: The materials in each layer are two materials that are alternately distributed. The two materials are selected from any two of palladium, cobalt, nickel, copper and gold.

[0050] Designed to meet the "mechanical-electrical performance balance" requirements of conventional testing scenarios. Due to the inherent differences in hardness, conductivity, and fatigue resistance among different metals (e.g., copper's conductivity is more than three times that of palladium, and palladium's hardness is 1.5 times that of copper), alternating layers of two metals allow the complementary advantages of each layer. For example, alternating palladium and copper layers utilize the copper layer to ensure low-loss signal transmission while the palladium layer enhances the overall wear resistance of the probe; alternating cobalt and nickel layers leverage the high yield strength (450 MPa) of cobalt to strengthen the probe's bending resistance, combined with the good ductility of nickel to prevent breakage, making it suitable for testing scenarios involving frequent insertion and removal. This combination eliminates the need for non-metallic materials, offers strong process compatibility, and is a universal solution that balances performance and manufacturing feasibility.

[0051] The core of this scheme is to achieve composite properties that cannot be achieved by a single material through the alternating layering of two metallic materials. For example, when a palladium-copper alternation is selected, palladium's hardness (approximately 400 HV) and corrosion resistance are superior to copper, which can improve the structural stability and lifespan of the probe; copper's electrical conductivity (approximately 5.96 × 10⁻⁶) is also superior. 7 The S / m ratio is more than three times that of palladium, which can reduce signal transmission loss. In practical implementation, the probe with a total thickness of 16μm can be set as a 4-layer structure (palladium 3μm-copper 5μm-palladium 3μm-copper 5μm), and the interlayer metallurgical bonding is achieved through MEMS electroplating process. Simulation comparison shows that the BCF stability (standard deviation 2.5mN) of this structure is better than that of the all-palladium structure (standard deviation 4.8mN), while the signal transmission efficiency is improved by 30%.

[0052] If a "cobalt-nickel" alternation is selected (cobalt yield strength 450MPa, nickel 300MPa), the cobalt layer can enhance the probe's resistance to bending, while the nickel layer ensures ductility. This is suitable for scenarios requiring frequent deformation, and tests have shown that its fatigue life is 60% higher than that of an all-nickel structure.

[0053] like Figure 10 The diagram shown is a schematic of the copper-rhodium material distribution in a MEMS vertical needle.

[0054] In this structure, different metallic materials are arranged in layers according to a predetermined order. For example, a copper layer is used to improve electrical conductivity, while a rhodium layer is used to improve the tip hardness and wear resistance. By rationally designing the distribution and thickness ratio of different materials, the mechanical strength and durability of the probe can be improved while ensuring electrical performance.

[0055] Option 2: The first and last layers are made of PI material (thickness 2μm~5μm).

[0056] This solution is designed to address the "insulation and short-circuit protection" requirements in high-voltage testing or high-density layout scenarios. In high-voltage testing (such as power chip testing), the distance between the probe and adjacent components is extremely small, and direct exposure of the metal layer can easily lead to short circuits due to leakage; while PI (polyimide) material has 10 14 With an ultra-high insulation resistance of over Ω·cm and a temperature range of -269 to 400°C, it can withstand harsh testing environments. By setting the PI as the outermost layer (the first and last layers), an "insulating protective layer" can be formed without affecting the conductivity of the intermediate metal layer, isolating the metal layer from the external structure. At the same time, the thickness range of 2μm to 5μm ensures the insulation effect without excessively increasing the overall size of the probe, which is suitable for the miniaturization requirements of MEMS.

[0057] In practical implementation, a probe with a total thickness of 20μm can be configured with 5 layers: PI (3μm) - palladium (4μm) - copper (6μm) - palladium (4μm) - PI (3μm). The PI layer is bonded to the metal layer through an adhesive coating-curing process, with interlayer adhesion ≥5N / cm. Tests show that this structure exhibits no breakdown at 1000V, while the metal probe without the PI layer short-circuits at 300V. Simultaneously, the PI layer reduces metal layer oxidation, decreasing the probe's performance degradation rate from 15% to 5% under humid and hot conditions (85℃ / 85%RH).

[0058] Option 3: At least one layered material is graphene.

[0059] This solution is designed to meet the "ultra-low loss" requirements of high-frequency signal transmission scenarios. In high-frequency tests of 5G chips and RF devices, the signal attenuation of traditional metallic materials increases significantly with increasing frequency (e.g., pure copper attenuates by -0.8dB at 10GHz), while graphene's conductivity (10... 8The S / m ratio is more than 10 times that of copper, and the thickness can be as thin as 0.34nm (a single atomic layer), which can significantly reduce high-frequency signal transmission loss without increasing the overall thickness of the probe. By embedding a graphene layer in the layers (such as adding a 0.5μm thick graphene layer between metal layers), the signal attenuation of the probe at 10GHz can be reduced to below -0.3dB. At the same time, the high Young's modulus (1TPa) of graphene is used to further improve the structural stability of the probe and meet the stringent requirements of high-frequency scenarios.

[0060] In practical implementation, a single layer of graphene (0.5 μm thick) can be embedded in a 5-layer structure: palladium (3 μm) - graphene (0.5 μm) - copper (5 μm) - graphene (0.5 μm) - palladium (3 μm). The graphene is transferred to the surface of the metal layer via chemical vapor deposition (CVD) to form an ohmic contact with the metal. Simulations show that the attenuation of this structure at 10 GHz high-frequency signal transmission (-0.3 dB) is only 37.5% of that of the all-copper structure (-0.8 dB); at the same time, the Young's modulus of graphene (1 TPa) is much higher than that of metal, which can increase the stiffness of the probe bending part by 20% and reduce contact instability caused by high-frequency vibration.

[0061] In summary, Option 1 achieves comprehensive mechanical and electrical performance through complementary properties between metals; Option 2 enhances insulation and protection through surface non-metallic materials; and Option 3 breaks through the performance limits of traditional materials by introducing graphene. It should be noted that all three are independent and optional technical solutions, which can be flexibly selected according to specific application scenarios (such as general testing, high-voltage environments, high-frequency signal transmission, etc.).

[0062] Example 3 Optionally, the layering process can be any one or a combination of at least two of the following: symmetrical layering, asymmetrical layering, gradient layering, and linear layering.

[0063] Furthermore, the needle tip region of the 3D model is layered with a metal layer whose hardness is higher than that of the corresponding layer of the needle body. A reinforcing structure is provided at the transition area between the metal layer and the corresponding layer of the needle body. The material of the metal layer is rhodium. The number of layers obtained by the layering process is 3 to 10, and the thickness of each layer is independent, ranging from 2 μm to 10 μm.

[0064] In one example, the layered processing can employ a combination of "symmetrical layering + tip reinforcement." For a MEMS vertical needle designed for high-temperature environments (operating temperature -40~125℃), its 3D model has a total thickness of 15μm, symmetrically divided into 5 layers along the needle thickness direction (layers 1 and 5 are 2μm thick, layers 2 and 4 are 3μm thick, and the middle layer is 5μm thick). In the tip region (50μm in length), layers 1 and 5 are replaced with rhodium (hardness 1200HV, higher than palladium's 400HV), and a 5μm radius rounded corner reinforcement structure is set in the transition region between the rhodium layer and the adjacent palladium layer to avoid stress concentration between layers. Simulations show that this design increases the tip contact hardness by 3 times while reducing stress in the transition region by 15%, resolving the contradiction of traditional single-material probes where "the tip is prone to wear or the body is prone to breakage." In physical testing, after 100,000 insertion and removal cycles, the tip wear is only 1 / 5 of that of a traditional palladium needle, proving that this layered approach can significantly improve the probe's fatigue resistance.

[0065] like Figure 7 The diagram shows the OD component of a MEMS vertical needle, where OD stands for Out-of-plane Deformation, i.e., the surface deformation component. During the probe's compression process, the bending structure will generate a certain out-of-plane displacement. By analyzing the OD component, the deformation stability of the probe in the spatial direction can be evaluated, thereby avoiding contact instability or signal distortion caused by structural instability.

[0066] Example 4 Optionally, the contact settings for the single-needle stress simulation are as follows: the adjacent layers are bonded together, and the probe and the opening surfaces of the upper and lower guide plates, the probe and the needle tip contact cover plate, and the probe and the needle tail contact cover plate are all in frictional contact. The friction coefficient of the frictional contact is set to 0.1, the contact stiffness is set to 0.1, and the damping coefficient is set to 0.01. Furthermore, the large deformation calculation is enabled when solving the single-needle stress simulation.

[0067] In one example, during the single-needle stress simulation, the contact settings were as follows: adjacent layers used "bound contact" (no relative sliding), while the probe and the opening surfaces of the upper and lower guide plates, as well as the needle tip / tail and the cover plate, were all set to "friction contact," with a friction coefficient of 0.1 (matching the dry friction characteristics between metals), a contact stiffness of 0.1 (avoiding stress distortion caused by excessive constraint), and a damping coefficient of 0.01 (simulating contact impact buffering). Simultaneously, large deformation calculation was enabled (because the probe bending can reach 20% of its own length). Comparative tests showed that the calculated BCF value (60mN) without large deformation calculation deviated by 25% from the measured value (80mN), while the deviation decreased to 5% after enabling it. Using the above friction parameters, the simulated needle tip sliding amount (2μm) was basically consistent with the high-speed camera's measured result (1.8μm), proving that this setting can accurately reproduce actual contact behavior.

[0068] Example 5 Optionally, when assigning physical property parameters to each layer, the thermal expansion coefficient, elastic modulus, Poisson's ratio, yield strength, thermal conductivity, and resistivity of each material are set separately according to the temperature range of -40℃ to 175℃.

[0069] like Figure 4 The image shows a schematic diagram of the thermal simulation of a MEMS vertical probe. During the thermo-mechanical coupled simulation, by applying a temperature field or current load to the probe structure, the temperature distribution and thermal expansion deformation of each layer can be obtained. Due to the differences in the coefficients of thermal expansion of different materials, thermal stress will be generated between the layers. This simulation can be used to evaluate the reliability of the probe under high-temperature or high-current environments.

[0070] The single-needle force simulation also includes thermodynamic coupling simulation, or current withstand simulation by applying voltage to both ends of the probe to obtain thermal expansion deformation data and equilibrium contact force BCF of the probe under different currents.

[0071] In one example, when assigning material parameters to each layer, the coefficient of thermal expansion of palladium was set to 11.8 × 10⁻⁶ for a wide temperature range of -40 to 175 °C. -6 / ℃ (-40℃) to 13.5×10 -6 / ℃ (175℃), copper is set at 16.5×10 -6 / ℃ to 19.0×10 -6 The influence of temperature on BCF was analyzed by thermo-mechanical coupling simulation: the results showed that at 175℃, the probe's thermal expansion caused the BCF to increase to 90mN (75mN at room temperature), and a 0.5μm cold shrinkage compensation amount needs to be reserved during optimization.

[0072] Furthermore, current withstand simulation with 1A current applied to both ends of the probe shows that the temperature rise of the copper layer (25℃) is higher than that of the palladium layer (15℃), and the interlayer stress caused by the maximum temperature difference is 50MPa (lower than the material yield strength), proving that the design can work stably under 1A current, solving the problem of performance drift of traditional probes under high temperature or high current.

[0073] Example 6 Optionally, the external dimensional parameters include needle arm width, needle arm thickness, bending radius, and bending position; the layering parameters include the number of layers and the thickness of each layer; the parameterized simulation settings are achieved by parameterizing the layered cross-sections using simulation software, which automatically calculates and obtains the optimal layer thickness scheme.

[0074] like Figure 5The diagram shows the application structure of MEMS vertical pins in a testing system. Multiple MEMS vertical pins can be arranged in an array via a guide plate and form electrical contact with the pads of the chip under test, thereby achieving signal detection or transmission. This structure is widely used in semiconductor testing, packaging inspection, and MEMS device signal acquisition.

[0075] Optionally, the number of upper and lower guide plates is 2 to 4 layers, and the upper and lower guide plates are respectively located in the straight areas at both ends of the probe; the single needle force simulation also includes simulation optimization of the opening size and opening chamfer of the upper and lower guide plates.

[0076] In one example, during the optimization of the external dimensions, the needle arm width was set to 40–60 μm, the bending radius to 20–40 μm, and the layer thickness increments to 0.5 μm. A script was written using ANSYS Parametric Design Language (APDL) to automatically generate 100 parameter combinations and calculate the BCF and stress values. After optimization using a genetic algorithm, the optimal solution was obtained: a needle arm width of 52 μm, a bending radius of 32 μm, and alternating layer thicknesses of 3 μm (palladium) and 2 μm (copper). This process took only 2 hours, a 24-fold improvement in efficiency compared to manual trial and error (2 days). Furthermore, the optimized BCF standard deviation (3 mN) was significantly lower than the initial solution (8 mN), demonstrating that parametric simulation can quickly find a robust solution.

[0077] like Figure 13 The diagram shows a cantilevered 3D MEMS structure. In this structure, the MEMS vertical needle achieves elastic deformation capability in three-dimensional space through the cantilever structure, enabling the probe to maintain stable contact force and good resilience when under pressure, thereby improving the overall reliability of the probe array.

[0078] Example 7 A 1μm thick coating is applied to the corresponding layer of the needle body surface of the 3D model. The coating is an insulating coating or a high-temperature alloy coating. The insulating coating is made of PI, and the high-temperature alloy coating is made of TiC-Ni. The contact surface between the coating and the corresponding layer of the needle body is designed to be bonded.

[0079] like Figure 14 The diagram shows a schematic of the surface coating structure of a MEMS vertical probe. A protective coating, such as a PI (Polyimide) insulating coating or a TiC-Ni high-temperature alloy coating, is applied to the probe surface. This coating improves the probe's insulation performance, oxidation resistance, and high-temperature resistance, thereby enhancing the probe's stability and lifespan in complex environments.

[0080] A 1μm thick PI insulating coating was added to the outer surface of the needle body (outer layers 1 and 5), and connected to the metal layer via a "bonding contact" (simulating MEMS coating process); simulation showed that this coating reduced the insulation resistance between the probe and the guide plate from 10 ohms. 8 Ω increased to 10 13 Ω, meeting the high-pressure testing requirements. For high-temperature scenarios, the coating was replaced with a TiC-Ni high-temperature alloy (melting point 1400℃). After a 300℃ cycle test, the probe BCF decay rate (5%) was significantly reduced compared to the uncoated solution (15%), proving that the coating can effectively protect the metal layer from high-temperature oxidation.

[0081] In one possible implementation, the simulation test consistency iteration includes the following.

[0082] If there is a difference between the measured data and the simulation data of the physical probe, adjust the material physical property parameters, layer thickness or vertical needle shape parameters of the corresponding layer based on the difference, and re-perform single needle force simulation and parameter optimization; until the deviation between the measured data and the simulation data is less than the preset threshold.

[0083] Therefore, in the simulation consistency iteration, the first physical test found that the measured BCF value (68mN) was 9% lower than the simulated value (75mN). The analysis showed that the actual elastic modulus of the copper layer (105GPa) was lower than the simulation set value (110GPa). After correcting the parameters, the second simulation BCF was 70mN, reducing the deviation from the measured value to 2.9%. In the next iteration, the palladium layer thickness was increased from 3μm to 3.2μm, which improved the BCF to 75mN, meeting the design requirements. The entire process only requires two rounds of physical production, shortening the cycle by 60% compared to the traditional method (5 rounds). Moreover, the prediction accuracy of the final simulation model (deviation <3%) can be directly used for the design of subsequent products in the same series, significantly reducing R&D costs.

[0084] On the other hand, a layered alloy MEMS vertical pin simulation design device is provided, the device comprising: The model building module is used to build a 3D model of the initial vertical probe and to perform layering processing on the 3D model along the probe thickness direction; The parameter setting module is used to assign physical property parameters of the corresponding materials to each layer and to set the binding of adjacent layers. The binding settings match the alloy characteristics of the layered structure in the MEMS layered manufacturing process. The simulation operation module is used to add upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate to the simulation environment based on the 3D model and actual working conditions. The single-needle simulation module is used to set the upper and lower guide plates and the needle tail contact cover plate as fixed constraints, and apply a preset displacement load to the needle tip contact cover plate to perform single-needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of the single needle. The parameter adjustment module is used to adjust the external dimensions and layering parameters of the vertical needle based on the balanced contact force BCF, stress and deformation data, and optimize them through parametric simulation settings to obtain a layering scheme and external structure that meets performance requirements. The simulation testing module is used to produce physical probes using MEMS technology according to the layered scheme and external structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probes are compared with the simulation data to perform simulation consistency iteration.

[0085] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0086] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware, or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk. The above descriptions are merely optional embodiments of this application and are not intended to limit the application. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A simulation design method for layered alloy MEMS vertical pins, characterized in that, The method includes: A preliminary 3D model of the vertical probe was created, and the 3D model was layered along the probe thickness direction. Each layer is assigned the physical property parameters of the corresponding material, and adjacent layers are bound together. The binding settings match the alloy characteristics of the layered structure in the MEMS layered manufacturing process. Based on the 3D model and actual working conditions, upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate are added to the simulation environment. The upper and lower guide plates and the needle tail contact cover plate are set as fixed constraints, and a preset displacement load is applied to the needle tip contact cover plate to perform single needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of a single needle. Based on the balanced contact force BCF, stress, and deformation data, the external dimensions and layering parameters of the vertical needle are adjusted using multiple parameters, and optimized through parametric simulation settings to obtain a layering scheme and external structure that meet performance requirements. A physical probe is produced using MEMS technology based on the layered scheme and external structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probe are compared with the simulation data to perform simulation consistency iteration.

2. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The layering process is any one or a combination of at least two of the following: symmetrical layering, asymmetrical layering, gradient layering, and linear layering. Furthermore, the needle tip area of ​​the 3D model is designed with a metal layer that has a higher hardness than the corresponding layer of the needle body. The transition area between the metal layer and the corresponding layer of the needle body is provided with a reinforcing structure at the connection point. The material of the metal layer is rhodium. The number of layers obtained by the layering process is 3 to 10, and the thickness of each layer is independent, ranging from 2 μm to 10 μm.

3. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, Each layer consists of an alternating distribution of two materials, selected from any two of palladium, cobalt, nickel, copper, and gold; or, The first and last layers of the 3D model are made of non-metallic materials, specifically PI materials, and the thickness of the first and last layers is 2μm to 5μm. or, At least one layer of material is graphene.

4. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The contact settings for the single-needle stress simulation are as follows: the adjacent layers are bonded together, and the probe and the opening surfaces of the upper and lower guide plates, the probe and the needle tip contact cover plate, and the probe and the needle tail contact cover plate are all in frictional contact. The friction coefficient of the frictional contact is set to 0.1, the contact stiffness is set to 0.1, and the damping coefficient is set to 0.

01. Furthermore, the large deformation calculation is enabled when solving the single-needle stress simulation.

5. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, When assigning physical property parameters to each layer of material, the thermal expansion coefficient, elastic modulus, Poisson's ratio, yield strength, thermal conductivity and resistivity of each material are set separately according to the temperature range of -40℃ to 175℃. The single-needle force simulation also includes thermodynamic coupling simulation, or current withstand simulation by applying voltage to both ends of the probe to obtain thermal expansion deformation data and equilibrium contact force BCF of the probe under different currents.

6. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The external dimensional parameters include needle arm width, needle arm thickness, bending radius, and bending position; the layering parameters include the number of layers and the thickness of each layer; the parameterized simulation settings are achieved by setting the layered cross-sections using simulation software, which automatically calculates and obtains the optimal layer thickness scheme.

7. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The number of upper and lower guide plates is 2 to 4 layers, and the upper and lower guide plates are respectively located in the straight area at both ends of the probe; the single needle force simulation also includes simulation optimization of the opening size and opening chamfer of the upper and lower guide plates.

8. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The method further includes: A 1μm thick coating is applied to the corresponding layer of the needle body surface of the 3D model. The coating is an insulating coating or a high-temperature alloy coating. The insulating coating is made of PI, and the high-temperature alloy coating is made of TiC-Ni. The contact surface between the coating and the corresponding layer of the needle body is designed to be bonded.

9. The layered alloy MEMS vertical needle simulation design method according to claim 1, characterized in that, The process of performing simulation consistency iteration includes: If there is a difference between the measured data and the simulation data of the physical probe, adjust the material physical property parameters, layer thickness or vertical needle shape parameters of the corresponding layer based on the difference, and re-perform single needle force simulation and parameter optimization. Until the deviation between the measured data and the simulation data is less than the preset threshold.

10. A layered alloy MEMS vertical needle simulation design device, characterized in that, The device includes: The model building module is used to build a 3D model of the initial vertical probe and to perform layering processing on the 3D model along the probe thickness direction; The parameter setting module is used to assign physical property parameters of the corresponding materials to each layer and to set the binding of adjacent layers. The binding settings match the alloy characteristics of the layered structure in the MEMS layered manufacturing process. The simulation operation module is used to add upper and lower guide plates, needle tip contact cover plate, and needle tail contact cover plate to the simulation environment based on the 3D model and actual working conditions. The single-needle simulation module is used to set the upper and lower guide plates and the needle tail contact cover plate as fixed constraints, and apply a preset displacement load to the needle tip contact cover plate to perform single-needle force simulation and obtain the equilibrium contact force BCF, stress and deformation data of the single needle. The parameter adjustment module is used to adjust the external dimensions and layering parameters of the vertical needle based on the balanced contact force BCF, stress and deformation data, and optimize them through parametric simulation settings to obtain a layering scheme and external structure that meets performance requirements. The simulation testing module is used to produce physical probes using MEMS technology according to the layered scheme and external structure. The measured equilibrium contact force (BCF), stress, and deformation data of the physical probes are compared with the simulation data to perform simulation consistency iteration.

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