A method for fabricating MEMS probes using ion implantation to improve electrical performance

Abstract

The present invention belongs to the technical field of MEMS probes, and specifically relates to a method for fabricating MEMS probes that uses ion implantation to improve electrical performance. First, a probe substrate of silver target copper alloy is fabricated, and rhodium ions are implanted into the tip part of the probe to form a required doped layer. In the present invention, rhodium metal is implanted on the silver target copper alloy substrate, significantly improving the electrical performance of the probe and enabling it to perform excellently in high-demand application scenarios; the implanted rhodium metal significantly enhances the wear resistance of the probe tip and extends the service life of the probe; rhodium metal has excellent antioxidant properties, enabling the probe to maintain good performance even at high temperatures and in harsh environments.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS probes, and particularly to a method for manufacturing MEMS probes using ion implantation to improve electrical performance. Background Art

[0002] With the rapid development of AI technology and high-performance computing, high-power and high-data-transfer-rate chips are widely used in fields such as data centers and supercomputers. The performance testing of these chips places extremely high requirements on probes, which need to meet three main requirements: high precision, large current, and high-speed data transmission. Traditional probe manufacturing methods such as chemical etching and mechanical polishing can meet the basic needs, but they have limitations in precisely controlling the shape and performance of the probe tip. Summary of the Invention

[0003] To solve the above problems, the present invention provides a method for manufacturing MEMS probes using ion implantation to improve electrical performance.

[0004] Therefore, the technical solution of the present invention is as follows: A method for manufacturing MEMS probes using ion implantation to improve electrical performance includes the following steps:

[0005] S1. Prepare a silicon wafer substrate and perform pre-treatment;

[0006] S2. Deposit a TiNi seed layer on the silicon substrate;

[0007] S3. Develop a probe pattern on the TiNi seed layer through photolithography;

[0008] S4. Perform probe electroplating;

[0009] S5. Perform CMP to grind the upper part of the probe flat;

[0010] S6. Perform photolithography and develop on the probe to expose the probe tip part;

[0011] S7. Perform ion implantation on the tip part:

[0012] S7.1. Design implantation parameters: Determine the ion type, dose, energy, and implantation angle;

[0013] S7.2. Inject the selected ions into the probe tip part to form the required doped layer;

[0014] S8. Remove the photoresist and strip out the probe;

[0015] S9. Anneal the probe tip part to activate the doped atoms and repair lattice damage;

[0016] S10. Process the tip part of the probe into the required shape and size.

[0017] Based on the above solution and as the preferred solution of the above solution: The implanted ion species is rhodium ions, the dose is 1×10^15 cm^-2, the energy is 50 keV - 60 keV, and the implantation angle is 0°.

[0018] Based on the above solution and as the preferred solution of the above solution: The total length of the probe is 6.5 mm, and the length of the tip part is 450 microns.

[0019] Based on the above solution and as the preferred solution of the above solution: In step S4, the electroplating solution is a silver target copper alloy.

[0020] Based on the above solution and as the preferred solution of the above solution: In step S10, the tip part of the probe is processed by chemical etching or mechanical polishing methods.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] Injecting rhodium metal onto a silver target copper alloy substrate significantly improves the electrical performance of the probe, enabling it to perform excellently in high - requirement application scenarios and becoming a key component of advanced microelectronics test systems.

[0023] The implanted rhodium metal significantly enhances the wear resistance of the probe tip, extending the service life of the probe; rhodium metal has excellent oxidation resistance, enabling the probe to maintain good performance even at high temperatures and in harsh environments.

[0024] The implanted rhodium metal improves the conductivity of the probe, enhances the current - carrying capacity of the probe, ensures the reliability of high - current and high - speed data transmission, and supports the test requirements of kilowatt - level high - power chips.

[0025] Through ion implantation technology, the overall performance of the probe is more stable, reducing the resistance of the tip part of the probe itself. The contact impedance is reduced from the original 2Ω to about 0.5Ω. Due to high - energy ion implantation, the 450 - micron tip part of the probe can maintain high performance consistency, reducing performance fluctuations and test errors caused by tip wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the preparation flow chart of the present invention;

[0027] Figure 2 is the test result graph of the current - carrying capacity of the probe. The orange curve is the test result of the probe after ion implantation, and the blue curve is the test result of the probe before ion implantation;

[0028] Figure 3It is a test result graph of the probe contact impedance. The orange curve is the test result of the probe after ion implantation, and the blue curve is the test result of the probe before ion implantation.

[0029] The markings in the figure are: silicon wafer substrate 1, TiNi seed layer 2, probe pattern 3, probe 4, tip part 41. Detailed implementation mode

[0030] In the description of the present invention, it should be noted that for the orientation terms, if there are terms such as "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the indicated orientation and position relationship are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present invention.

[0031] In addition, if there are terms such as "first" and "second", they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "several" and "a number of" is two or more, unless otherwise specifically defined.

[0032] Embodiment 1

[0033] The method for manufacturing a MEMS probe using ion implantation to improve electrical performance in this embodiment includes the following steps:

[0034] S1. Prepare the silicon wafer substrate 1 and perform pre-treatment;

[0035] The silicon wafer needs to be chemically cleaned (such as ultrasonic cleaning with acetone and isopropyl alcohol) to remove organic pollutants, then rinsed with deionized water and dried with nitrogen gas, and finally baked on a hot plate at 150 °C for 5 minutes to thoroughly dry.

[0036] S2. Deposit the TiNi seed layer 2 on the silicon substrate;

[0037] Adopt magnetron sputtering technology to deposit a titanium-nickel (TiNi) seed layer on the silicon substrate. Titanium (Ti) is used as an adhesion layer to enhance the adhesion between the seed layer and silicon, and nickel (Ni) is used as a conductive layer to promote the growth of subsequent electroplated metal.

[0038] S3. Develop the probe pattern 3 on the TiNi seed layer through photolithography;

[0039] Spin - coat a negative photoresist (such as AZ NLof 2070) with a thickness of 7 μm. Transfer the mask pattern to the photoresist through an ultraviolet lithography machine (wavelength 365 nm). After exposure, the developer (such as AZ 726 MIF) dissolves the unexposed area, exposing the probe pattern area of the TiNi seed layer.

[0040] S4. Conduct probe electroplating;

[0041] Select a silver - target copper - alloy electroplating solution. Control the metal deposition rate by adjusting the current density (2 - 10 mA / cm²) and electroplating time (30 - 120 seconds) to form the probe body. The total length of the probe is 6.5 mm, and the length of the tip part that can be used is 450 μm.

[0042] S5. Conduct CMP to grind the area above the probe 4 flat;

[0043] Use alumina or silica slurry, combined with a polyurethane polishing pad, to grind the surface at a rotational speed of 50 - 100 rpm. Ensure that only the metal layer in the probe structure area is retained by real - time monitoring of surface roughness or thickness changes.

[0044] S6. Conduct photolithography and development on the probe to expose the tip part 41 of the probe;

[0045] Spin - coat a negative photoresist. Transfer the mask pattern to the photoresist through an ultraviolet lithography machine. After exposure, the developer dissolves the unexposed area, exposing the tip part area of the probe.

[0046] S7. Conduct ion implantation on the tip part:

[0047] S7.1. Design the implantation parameters: Select rhodium ions, with a dose of 1 × 10^15 cm^-2, an energy of 50 keV, an implantation angle of 0°, and the implantation area is the tip part of the probe.

[0048] S7.2. Inject the selected rhodium ions into the tip part of the probe to form the required doped layer.

[0049] S8. Remove the photoresist and strip out the probe 4;

[0050] Adopt wet stripping (soaking in acetone + ultrasonic assistance) or dry - process plasma ashing (O2 plasma) to completely remove the residual photoresist;

[0051] Use a mixed acid solution (such as HF:HNO3 = 1:10) to etch the TiNi seed layer not covered by electroplated metal, and finally only the probe structure is retained.

[0052] S9. Anneal the tip part of the probe to activate the doped atoms and repair the lattice damage;

[0053] S10. Processing the probe tip into a desired shape and size by chemical etching, mechanical polishing, and the like.

[0054] After the above-mentioned process, the wear resistance, oxidation resistance, conductivity and stability of the probe are significantly improved. The test results show that the contact resistance is reduced and the performance is stable.

[0055] Example 2

[0056] The rest of the process of this embodiment is the same as that of embodiment 1, except that:

[0057] The ion implantation process parameters are as follows: rhodium ions are selected, the dose is 1 × 10^15 cm^-2, the energy is 60 keV, the implantation angle is 0°, and the implantation area is the probe tip.

[0058] Compared with Example 1, the wear resistance and conductivity of the probe in this embodiment are further improved, but the contact resistance is slightly increased. The overall performance is still better than that of the traditional probe.

[0059] The MEMS probe manufactured in Example 1 was subjected to performance tests, including current carrying capacity (CCC ISMI), maximum allowable current (CCC MAC), contact resistance (Contact Resistance) and life time test (Life Time Test).

[0060] The probe current carrying capacity test method aims to test the maximum carrying capacity of the probe when a current is applied once, and to evaluate the limit performance of the probe in a high current environment. The test steps are as follows:

[0061] A1. Sample preparation: Select a probe sample and ensure that the probe surface is clean and free of contamination.

[0062] A2. Initial Measurement: Under standard overdrive conditions, measure the initial spring force of the probe to establish a baseline.

[0063] A3. Current application: Start applying current at 75% of the maximum current carrying value estimated by the probe supplier, in increments of 25 mA, for 2 minutes, with a 10-second cool-down period between each application.

[0064] A4. Spring force monitoring: Measure the probe's spring force each time current is applied. When the spring force drops 20% from the initial value, record this current as the probe's maximum carrying current.

[0065] The Contact Resistance test method aims to measure the resistance between the probe and the test point to evaluate its conductivity and stability. The test steps are as follows:

[0066] B1. Test Equipment: Use a contact resistance tester to apply a constant current.

[0067] B2. Sample Preparation: Install the probe on the test bench to ensure stable contact between the probe and the test point.

[0068] B3. Measurement Process: Apply a standard current (such as 1 mA) and record the contact resistance value of the probe. Measure multiple times to evaluate the fluctuation range of the contact resistance.

[0069] B4. Result Analysis: Calculate the average value and standard deviation of the contact resistance to ensure that the contact resistance of the probe is within the target value (such as 0.5 Ω).

[0070] Objective of the Life Time Test Method: Verify the durability and performance stability of the probe under long-term repeated use. The test steps are as follows:

[0071] C1. Test Conditions: Set the number of times the probe contacts under standard over-drive conditions (such as 2 million Touch Downs).

[0072] C2. Test Process: Simulate the real test environment and use automated equipment to conduct cyclic contact tests on the probe. Measure performance parameters such as the contact resistance and spring force value of the probe every certain number of times (such as 500,000 times).

[0073] C3. Failure Judgment: When the spring force of the probe drops by more than 20% or the contact resistance exceeds the target value, it is determined that the probe's life has ended.

[0074] C4. Data Recording: Record the performance change trend of the probe during the test for analyzing the influencing factors of the life.

[0075] In the present invention, by injecting rhodium metal into the silver target copper alloy substrate, the electrical performance of the probe is significantly improved, making it perform excellently in high-demand application scenarios. By optimizing the process parameters, the performance of the probe can be further enhanced to meet the requirements of different application scenarios.

[0076] Specific optimization points are as follows:

[0077] Wear Resistance: The injected rhodium metal significantly enhances the wear resistance of the probe, extends the service life of the probe, reduces the requirement for the cleaning frequency of the probe by 50%, and increases the life from the traditional 800,000 Touch Downs to 2 million Touch Downs.

[0078] Oxidation Resistance: Rhodium metal has excellent oxidation resistance, enabling the probe to maintain good performance under high temperature and harsh environments.

[0079] Conductivity: Such as Figure 2As shown, the current-carrying capacity of the probe before and after ion implantation was measured. The orange curve represents the test results of the probe after ion implantation, and the blue curve represents the test results of the probe before ion implantation. According to the chart data, the implanted rhodium metal improved the conductivity of the probe and its current-carrying capacity. For a cylindrical MEMS probe with a size of 60um * 60um, the current-carrying capacity increased from the original 1200 mA to 1800 mA, ensuring the reliability of high-current and high-speed data transmission and supporting the test requirements of high-power chips in the kilowatt range.

[0080] Stability: As Figure 3 shown, the contact resistance of the probe before and after ion implantation was measured. The orange color represents the test results of the probe after ion implantation, and the blue color represents the test results of the probe before ion implantation. According to the chart data, before ion implantation, the average contact resistance of the probe was stable at about 2 Ω, and after ion implantation, the average contact resistance of the probe was stable within the range of 0.5 Ω.

[0081] Through the ion implantation technology, the overall performance of the probe is more stable, reducing the resistance of the tip part of the probe itself. The contact impedance decreased from the original 2 Ω to about 0.5 Ω. Due to the high-energy ion implantation, the 450-micron tip part of the probe can maintain a high degree of performance consistency, reducing performance fluctuations and test errors caused by tip wear.

[0082] These improvements enable the probe to perform excellently in high-demand application scenarios such as AI artificial intelligence chips and become a key component of advanced microelectronic test systems.

[0083] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for fabricating a MEMS probe that improves electrical performance by ion implantation, characterized in that: It includes the following steps: S1. Prepare a silicon wafer substrate and perform pre-treatment; S2. Deposit a TiNi seed layer on the silicon substrate; S3. Develop a probe pattern on the TiNi seed layer through photolithography; S4. Perform probe electroplating; S5. Perform CMP to grind the area above the probes flat; S6. Perform photolithography and development on the probes to expose the probe tip parts; S7. Perform ion implantation on the tip parts: S7.

1. Design the implantation parameters: determine the ion type, dose, energy, and implantation angle; the implanted ion type is rhodium ions, the dose is 1×10^15 cm^-2, the energy is 50 keV - 60 keV, and the implantation angle is 0°; S7.

2. Implant the selected ions into the probe tip parts to form the required doped layer; S8. Remove the photoresist and strip out the probes; S9. Anneal the probe tip parts to activate the doped atoms and repair the lattice damage; S10. Process the probe tip parts into the required shape and size.

2. The method for fabricating a MEMS probe using ion implantation to improve electrical performance according to claim 1, wherein: The total length of the probe is 6.5 mm, and the length of the tip part is 450 microns.

3. The method for fabricating a MEMS probe using ion implantation to improve electrical performance as claimed in claim 1, wherein: In step S4, the electroplating solution is a silver target copper alloy.

4. A method for fabricating a MEMS probe using ion implantation to improve electrical performance, as claimed in claim 1, wherein: In step S10, the probe tip parts are processed by chemical etching or mechanical polishing methods.

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