A high-hardness and high-conductivity palladium-based alloy ultra-thin strip, a probe and a preparation method thereof

Abstract

This invention discloses a high-hardness, high-conductivity palladium-based alloy ultrathin strip, a probe, and a method for preparing the same. The palladium-based alloy ultrathin strip of this invention is composed of the following metal raw materials in the following mass ratios: Pd 46%~51%, Cu 38.5%~42.5%, Ag 8.5%~12.5%, Ru 0.2%~3.0%, and Pt 0.1%~0.5%. The phase composition of the palladium-based alloy ultrathin strip mainly consists of Pd-Ag solid solution, Pd-Cu solid solution, CuPd ordered phase, and Cu3Pd ordered phase, with an average grain size of 0.2~3 μm. Ru exists independently in elemental form, exhibiting a discontinuous fibrous distribution along the rolling direction in the macroscopic region. The finished palladium-based alloy ultrathin strip provided by this invention can be used directly as a probe component. Its preparation method has the characteristics of high yield and high production efficiency. The vertical probe based on the palladium-based alloy ultrathin strip has the basic characteristics of high hardness, high strength, high conductivity, high elasticity, high surface quality and high flatness of the palladium-based alloy ultrathin strip. It exhibits excellent current resistance, fatigue resistance and wear resistance in wafer testing.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, specifically relating to a high-hardness, high-conductivity palladium-based alloy ultrathin strip, probe, and its preparation method. Background Technology

[0002] Probes used in semiconductor wafer testing are core components and consumables, used for precise connections between the wafer / pin under test and the testing machine, enabling signal transmission to detect current, conductivity, and other functions. To meet minimum pitch requirements, probe sizes reach the micrometer level. Therefore, probes must possess sufficient hardness, strength, and elasticity, excellent current carrying capacity, and stable contact resistance at high and low temperatures to meet the requirements of probe structure design and operating environment.

[0003] In addition to the urgent need to resolve the contradiction between high electrical conductivity and excellent mechanical properties, with the increasing density of integrated circuits and the refinement of probes, minute defects on the probe surface (such as scratches, pits, inclusions, etc.) and poor flatness (such as warping, edge ripples, center ripples, etc.) are likely to greatly affect the probe yield and wafer inspection reliability. For example, if the probe breaks during repeated contact with the wafer under test, the oxidation of the probe surface will affect the contact resistance, and the warping of the probe will affect the consistency of the probe arrangement, thus causing an open circuit illusion. Therefore, higher requirements are placed on the surface quality and flatness of the materials used for probes.

[0004] Noble metal electrical contact materials exhibit stable physical and chemical properties at high temperatures, overcoming the shortcomings of probe materials such as Be-Cu alloys with Au coatings, which suffer from easy coating wear, and Re-W alloys, which exhibit poor high-temperature oxidation resistance. Palladium-based alloys, as a major alloy series among noble metal electrical contact materials, possess excellent high-temperature oxidation and corrosion resistance. Through a combination of homogenization, solid solution strengthening, work hardening, and ordered phase transformation, high electrical conductivity and excellent mechanical properties can be simultaneously achieved. Furthermore, by controlling strip shape and improving surface quality, the requirements for thickness uniformity, flatness, and surface quality in probe materials can be met, making them the probe materials with the best overall performance and the greatest potential.

[0005] This invention aims to provide a high-hardness, high-conductivity palladium-based alloy ultrathin strip, a probe, and a method for preparing the same. Summary of the Invention

[0006] The first objective of this invention is to provide a high-hardness, high-conductivity palladium-based alloy ultrathin strip. The second objective of this invention is to provide a method for preparing the palladium-based alloy ultrathin strip. The third objective of this invention is to provide a probe based on the palladium-based alloy ultrathin strip that has current resistance, fatigue resistance, and wear resistance.

[0007] The first objective of this invention is achieved by providing an ultrathin palladium-based alloy strip with high hardness and high electrical conductivity, composed of the following metal raw materials in the following mass ratios: Pd 46%~51%, Cu 38.5%~42.5%, Ag 8.5%~12.5%, Ru 0.2%~3.0%, and Pt 0.1%~0.5%.

[0008] The phase composition of the palladium-based alloy ultrathin strip mainly consists of Pd-Ag solid solution, Pd-Cu solid solution, CuPd ordered phase, and Cu3Pd.

[0009] It consists of an ordered phase with an average grain size of 0.2~3μm;

[0010] In the palladium-based alloy ultrathin strip, Ru exists independently in elemental form and is distributed discontinuously in a fibrous manner along the rolling direction in the macroscopic region. The diameter of the fibrous Ru is ≤400nm, and it is mainly 100nm and below.

[0011] The second objective of this invention is achieved by the preparation method of the high-hardness, high-conductivity palladium-based alloy ultrathin strip, which includes the steps of casting, solution treatment, large deformation cold rolling, surface polishing and cleaning, and aging leveling treatment.

[0012] The solution treatment and large deformation cold rolling process are carried out alternately, with no less than 3 alternating rolling cycles, and the total deformation of the large deformation cold rolling is 80-97%. The solution treatment method is to keep the ingot obtained from the melting and casting process at 750-950℃ for 2 hours in a vacuum furnace, and then cool it with N2 gas at a cooling rate of ≥15℃ / s.

[0013] The third objective of this invention is achieved by providing a probe based on the high-hardness, high-conductivity palladium-based alloy ultrathin strip, which has current resistance, fatigue resistance, and wear resistance. The probe is prepared by laser cutting the palladium-based alloy ultrathin strip.

[0014] The beneficial effects of this invention are as follows:

[0015] 1. The finished palladium-based alloy ultrathin strip provided by this invention can be used directly as a probe component. Its preparation method has the characteristics of high yield and high production efficiency. This preparation method is designed for the characteristics of use in probe design, integration and wafer inspection. It abandons the conventional method of improving flatness by separating the aging treatment and leveling or straightening of the profile into steps. Instead, it realizes aging and leveling simultaneously. In addition, this invention pays attention to the negative impact of poor surface quality of the profile and / or probe. It incorporates the improvement of surface quality and flatness into the preparation process of ultrathin strip. Therefore, it avoids the technical problems that may be encountered at the device end from the material end, thereby improving the probe yield and the reliability of wafer inspection.

[0016] 2. The vertical probe based on the palladium-based alloy ultrathin strip provided by the present invention possesses the basic characteristics of the palladium-based alloy ultrathin strip, such as high hardness, high strength, high conductivity, high elasticity, high surface quality and high flatness. It exhibits excellent current resistance, fatigue resistance and wear resistance in wafer testing. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the fabrication process of the palladium-based ultrathin tape and probe of this invention.

[0018] Figure 2 The image shows a comparison of the surface of the ultrathin strip prepared in Example 1 of the present invention before and after polishing. In this image, (a) and (c) are the overall effect and microscopic effect of the unpolished strip surface, respectively; and (b) and (d) are the overall effect and microscopic effect of the polished strip surface, respectively.

[0019] Figure 3 This is a schematic diagram of the aging treatment of the palladium-based ultrathin strip of the present invention, wherein 1—vacuum heat treatment furnace; 2—palladium-based ultrathin strip.

[0020] Strip; 3—leveling fixture;

[0021] Figure 4 The image shows the microstructure of fibrous Ru in the palladium-based ultrathin tape prepared in Example 1 as observed by scanning electron microscopy. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this does not limit the present invention in any way. Any modifications or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0023] This invention discloses a high-hardness, high-conductivity palladium-based alloy ultrathin strip, composed of the following metal raw materials in the following mass ratios: Pd 46%~51%, Cu 38.5%~42.5%, Ag 8.5%~12.5%, Ru 0.2%~3.0%, and Pt 0.1%~0.5%.

[0024] The phase composition of the palladium-based alloy ultrathin strip mainly consists of Pd-Ag solid solution, Pd-Cu solid solution, CuPd ordered phase, and Cu3Pd.

[0025] It consists of an ordered phase with an average grain size of 0.2~3μm;

[0026] In the palladium-based alloy ultrathin strip, Ru exists independently in elemental form. After intense plastic deformation, the Ru dispersed in the matrix is ​​distributed in a discontinuous fibrous manner along the rolling direction in the macroscopic region. The diameter of the fibrous Ru is 400 nm or less, with 100 nm or less being the main component.

[0027] This invention uses a palladium-silver-copper-ruthenium-platinum alloy as the probe material. In this pentagonal alloy, both Ag and Cu can exert solid solution strengthening effects in Pd. An appropriate amount of Ag can reduce the high resistivity effect caused by high Pd. Cu and Pd form ordered CuPd and Cu3Pd phases at low temperatures, which can significantly improve conductivity and hardness. In this alloy system, Ru has low solubility in Pd at low temperatures, so the Ru precipitate phase (solid solution) plays a role in dispersion strengthening. Pt not only has good oxidation resistance, but also can form ordered Cu3Pt and CuPt phases with Cu at low temperatures, playing a role in precipitation strengthening.

[0028] To maximize the alloy's strength and hardness through solid solution strengthening and precipitation strengthening, while considering the oxidation resistance requirements of the probe material, a mass fraction ratio of 46%~51% Pd, 38.5%~42.5% Cu, and 8.5%~12.5% ​​Ag was selected. To ensure that the addition of Ru and Pt is harmless or (and) beneficial to the mechanical properties and electrical conductivity of the strip, while guaranteeing good processability and formability, the addition of Ru and Pt should be 0.2%~3.0% and 0.1%~0.5%, respectively.

[0029] The palladium-based alloy ultrathin strip has a Vickers hardness of 450~500HV0.1, an electrical conductivity of 22~25%IACS, a tensile strength of 1100~1400MPa, an elastic modulus of 110~160GPa, a thickness of 30~60μm, a thickness tolerance of ≤1μm, and a surface free of oxidation, scratches, and pits, exhibiting a metallic luster and a surface roughness R. a ≤0.2μm, flatness ≤0.01mm.

[0030] This invention also provides a method for preparing the aforementioned high-hardness, high-conductivity palladium-based alloy ultrathin strip, the method comprising:

[0031] The process includes casting, solution treatment, large deformation cold rolling, surface polishing and cleaning, and aging leveling.

[0032] 1. Melting and Casting: This includes three steps: batching, melting, and casting. During the melting and casting process, the selection of the crucible, casting mold, melting power, holding time, and number of remelting cycles is beneficial for thoroughly stirring the melt, reducing alloy element segregation, removing gaseous impurities, and avoiding or mitigating casting defects such as porosity and shrinkage cavities. The temperature of the cooling water inlet during casting should not exceed 20℃.

[0033] The smelting is carried out using a vacuum high-frequency induction furnace. Specifically, the raw materials are placed into a zirconium oxide crucible, a vacuum is drawn, and the vacuum level is maintained at 10. -1For Pa and below, introduce protective argon gas, increase the melting power to a melting temperature of 1200~1600℃, and after all the raw materials have melted, hold for 8~12 minutes, then reduce the power to 0 kW. After the surface of the melt has solidified, adjust the power again to bring the temperature back to 1200~1600℃, and wait for the raw materials to melt again. The process from the solidification of the surface of the melt to remelting is called remelting, and this process should be repeated at least twice.

[0034] After the smelting is completed, it is poured into a copper mold to cool and solidify into an alloy ingot. The temperature of the condensate inlet is below 20°C.

[0035] 2. Solution treatment: This refers to the process of holding the alloy ingot at high temperature for an extended period in a vacuum heat treatment furnace. This reduces excessive internal stress in the ingot, weakens the segregation of Ag, Cu, Pt, and Ru, and achieves solid solution strengthening, homogenization of the microstructure, and other benefits. It also improves the ingot's machinability and prevents cracking during subsequent large-deformation cold rolling. The solution treatment temperature is 750~950℃, and the holding time is 2 hours. Annealing is performed in a vacuum furnace using N2 gas cooling at a rate ≥15℃ / s.

[0036] 3. Large deformation cold rolling: Based on the analysis of the processing parameter window of the palladium-based alloy, the rolling process is large deformation cold rolling, with a total deformation of 80% to 97%. Large deformation cold rolling has a strong effect of work hardening and grain refinement, so that the submicron deposits are arranged in a fibrous manner along the rolling direction.

[0037] Solution treatment and rolling are performed alternately, with no fewer than three alternations. At the same time, the deformation amount per pass is controlled to avoid the problems of high probability of cracking and low yield caused by strong processing. Specifically, the deformation amount per pass of the first large deformation cold rolling is no more than 20%, the deformation amount per pass of the second large deformation cold rolling is no more than 12%, and the deformation amount per pass of the third and subsequent large deformation cold rolling is no more than 10%.

[0038] 4. Surface polishing and cleaning: This process is designed to address surface quality defects such as scratches, oxidation, and stains introduced during processing and heat treatment. It includes two steps: surface polishing and ultrasonic cleaning.

[0039] 1) Surface Polishing: A continuous polishing equipment with three-stage brush wheels, equipped with appropriate brush wheels and polishing media, is used to complete the rough polishing, medium polishing, and precision polishing of ultra-thin strips in stages. The first-stage brush wheel is a nylon brush, the second and third-stage brush wheels are velvet brushes, the first and second-stage polishing media is 2.5~5μm diamond polishing slurry, and the third-stage polishing media is 0.05~1.5μm diamond polishing slurry. The brush wheel speed is 50~1000 r / min, and the strip winding and unwinding speed is 2~15 m / min.

[0040] 2) Ultrasonic cleaning: After polishing, the strip is further cleaned and dried in an ultrasonic bath.

[0041] 5. Aging and Leveling Treatment: This invention employs tension aging treatment. Specifically, the strip is fixed on a leveling fixture, placed in a vacuum heat treatment furnace, held at a certain temperature for a specific time, and then cooled with N2. The resulting product is the finished strip. The heating rate is ≥1℃ / s, the holding temperature is 350~420℃, the holding time is 0.5~3h, and the cooling rate is ≤3℃ / min. A holding temperature of 350~420℃ can initiate and / or promote ordered transformation, inducing the precipitation of CuPd and / or Cu3Pd phases, thereby significantly improving electrical conductivity and hardness. On the other hand, the temperature range of 350℃~420℃ is very suitable for strip leveling. Temperatures above this range tend to lead to severe losses in electrical conductivity and / or hardness, while temperatures below this range make it difficult to guarantee mechanical-electrical properties and leveling effects. The aging treatment simultaneously improves the hardness and electrical conductivity of the strip and improves its flatness, solving strip shape problems such as warping, edge ripples, and center waves, achieving two goals at once.

[0042] The present invention further provides a probe with current resistance, fatigue resistance and wear resistance based on the high hardness and high conductivity palladium-based alloy ultrathin strip. The preparation method is to obtain the target probe by laser cutting the palladium-based alloy ultrathin strip.

[0043] Example 1

[0044] (1) Pd, Ag, Cu, Ru and Pt with a purity of 99.9% or higher are mixed at mass fractions of 47%, 12%, 39.5%, 1.2% and 0.3% respectively, and then melted in a vacuum high-frequency induction furnace and cast into alloy ingots. The specific steps are as follows: the raw materials are put into a zirconia crucible, a vacuum is drawn, and the vacuum degree is 10 -1 For Pa and below, argon gas is introduced, and the power is increased to 1200℃. After all the raw materials have melted, the temperature is maintained for 10 minutes. The power is then reduced to 0, and after the surface of the melt solidifies, the power is adjusted back to 1500℃. The melting is repeated twice. After the melting is completed, the melt is poured into a copper mold to cool and solidify. The temperature of the cooling water inlet should not exceed 20℃.

[0045] (2) The obtained ingots were subjected to solution treatment followed by large deformation cold rolling three times in alternating cycles. The first solution treatment involved holding at 950℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 15℃ / s, followed by the first large deformation cold rolling, with a total deformation of 91% and a per-pass deformation of 18%. The second solution treatment involved holding at 850℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 15℃ / s, followed by the second large deformation cold rolling, with a total deformation of 84% and a per-pass deformation of 10%. The third solution treatment involved holding at 800℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 15℃ / s, followed by the third large deformation cold rolling, with a total deformation of 86% and a per-pass deformation of 8%. The final product was a strip with a thickness tolerance of 0.04 mm and a thickness tolerance of 1 μm or less.

[0046] (3) The obtained strip was mechanically polished using a three-stage brush wheel system. The first-stage brush wheel was a nylon brush, and the second and third-stage brush wheels were wool brushes. The polishing media for the first and second stages was 5μm diamond polishing slurry, and the polishing media for the third stage was 1.5μm diamond polishing slurry. The brush wheel speed was 800 r / min, and the strip winding and unwinding speeds were 4 m / min. After polishing, the strip was further cleaned and dried in an ultrasonic bath. Figure 2 It can be seen that the surface of the strip before polishing is grayish-white and not bright enough after oxidation. Figure 2 (a) has obvious scratches. Figure 2 (c) white lines), the surface of the strip after polishing has a bright metallic luster ( Figure 2 (b)), and there are no scratches after polishing. Figure 2 (d)).

[0047] (4) The cleaned strip is aged to obtain the target ultra-thin strip. The specific method is to fix the strip on a self-made leveling fixture, put it in a vacuum heat treatment furnace, keep it at 400℃ for 1 hour, with a heating rate of 5℃ / s, and use N2 cooling at a cooling rate of 1℃ / min.

[0048] (5) The ultrathin strip obtained in step (4) is laser-cut into a vertical probe.

[0049] Example 2

[0050] (1) Pd, Ag, Cu, Ru and Pt with a purity of 99.9% or higher are mixed at mass fractions of 48.7%, 10%, 41%, 0.2% and 0.1% respectively, and then melted in a vacuum high-frequency induction furnace and cast into alloy ingots. The specific steps are as follows: the raw materials are put into a zirconia crucible, a vacuum is drawn with a vacuum degree of 0.01 MPa or below, argon gas is introduced, the power is increased to 1200℃, after the raw materials are completely melted, the holding time is 8 minutes, the power is reduced to 0, after the surface of the melt solidifies, the power is adjusted to 1300℃ again, and the melting is repeated twice. After the melting is completed, the ingots are cast into copper molds to cool and solidify, and the temperature of the cooling water inlet is not higher than 20℃.

[0051] (2) The obtained ingot was subjected to solution treatment followed by large deformation cold rolling three times in alternating cycles. The first solution treatment involved holding at 900℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 18℃ / s, followed by the first large deformation cold rolling, with a total deformation of 91% and a per-pass deformation of 20%. The second solution treatment involved holding at 850℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 18℃ / s, followed by the second large deformation cold rolling, with a total deformation of 84% and a per-pass deformation of 12%. The third solution treatment involved holding at 850℃ for 2 hours in a vacuum furnace and cooling with N2 gas at a rate of 18℃ / s, followed by the third large deformation cold rolling, with a total deformation of 86% and a per-pass deformation of 10%. The final product was a strip with a thickness tolerance of 0.04 mm and a thickness tolerance of 1 μm or less.

[0052] (3) The obtained strip was mechanically polished using a three-stage brush wheel. The first-stage brush wheel for surface polishing was a nylon brush, and the second and third-stage brush wheels were wool brushes. The polishing media for the first and second stages was 5μm diamond polishing slurry, and the polishing media for the third stage was 1.5μm diamond polishing slurry. The brush wheel speed was 800r / min, and the strip winding and unwinding speed was 4m / min. After polishing, the strip was further cleaned and dried in an ultrasonic bath.

[0053] (4) The cleaned strip is aged to obtain the target ultra-thin strip. The specific method is to fix the strip on a self-made leveling fixture, put it in a vacuum heat treatment furnace, keep it at 350℃ for 1 hour, the heating rate is 5℃ / s, and use N2 cooling at a cooling rate of 1℃ / min.

[0054] (5) The ultrathin strip obtained in step (4) is laser-cut into a vertical probe.

[0055] Example 3

[0056] The process is basically the same as in Example 1, except that in step (4), the cleaned ultrathin strip is fixed on a self-made leveling fixture, placed in a vacuum heat treatment furnace, kept at 400°C for 3 hours, with a heating rate of 5°C / s, and cooled by N2 with a gas flow rate of 3°C / min.

[0057] Comparative Example 1

[0058] Compared to Example 1, Comparative Example 1 uses Pd 47% Ag 12% Cu 39.5% Ru 1.2% Pt 0.3% The ultra-thin strip is processed by (mass fraction). The difference between the ultra-thin strip preparation method and Example 1 is that the ingot obtained in step 1) is not subjected to the alternating solid solution and large deformation cold rolling process in step 2), and the surface polishing and cleaning in step 3) and the leveling process in step 4) are not performed.

[0059] (1) Pd, Ag, Cu, Ru and Pt with a purity of 99.9% or higher are mixed at mass fractions of 47%, 12%, 39.5%, 1.2% and 0.3% respectively, and then melted in a vacuum high-frequency induction furnace and cast into alloy ingots. The specific steps are as follows: the raw materials are put into a zirconia crucible, a vacuum is drawn with a vacuum degree of 10-1 Pa or less, argon gas is introduced, the power is increased to 1200℃, after the raw materials are completely melted, the temperature is held for 10 min, the power is reduced to 0, after the surface of the melt solidifies, the power is adjusted to 1500℃ again, and the melting is repeated twice. After the melting is completed, the ingots are cast into copper molds to cool and solidify, and the temperature of the cooling water inlet is not higher than 20℃.

[0060] (2) The obtained ingot is repeatedly solution-treated and cold-rolled to obtain a strip with a thickness of 0.04 mm and a thickness tolerance of 1 μm or less. The solution treatment is carried out in a vacuum furnace, and after holding at 850℃ for 2 hours, it is quickly water-cooled and then cold-rolled.

[0061] (3) The obtained strip is subjected to aging treatment to obtain the target ultrathin strip. The specific method is to fix the strip on a self-made leveling fixture, put it in a vacuum heat treatment furnace, keep it at 400℃ for 1 hour, with a heating rate of 5℃ / s, and use N2 cooling at a cooling rate of 1℃ / min.

[0062] (4) The ultrathin strip obtained in step (3) is laser-cut into a vertical probe.

[0063] Comparative Example 2

[0064] Compared to Example 1, Comparative Example 2 uses Pd 40% Ag 30% Cu 30%The (mass fraction) alloy was processed into an ultra-thin strip using the same method as in Example 1, and the strip was finally laser-cut into a vertical probe.

[0065] Detection example

[0066] The performance of the strips and probes prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are shown in Table 1.

[0067] Surface quality refers to the oxidation and scratches observed on the strip surface under a 20x microscope. Surface roughness is measured using a roughness meter, and the roughness is evaluated using the height characteristic parameter Ra.

[0068] Flatness was tested using a feeler gauge, with a 000-grade marble platform as the sample stage. The maximum gap between the sample and the sample stage was used as the evaluation index.

[0069] Table 1. Performance of the ultrathin strip and probe in specific embodiments 1-3 and comparative examples 1-2

[0070]

[0071] Note: "√" indicates that the surface has a metallic luster, is free from oxidation, scratches, pits, or bumps;

[0072] "×" indicates surface defects such as dullness, oxidation, scratches, pits, or bumps.

[0073] Results: As shown in Table 1, the Vickers hardness of the ultrathin strips in Examples 1-3 was 450-500 HV0.1, the electrical conductivity was 22-25% IACS, the tensile strength was 1100-1400 MPa, the elastic modulus was 110-160 GPa, the thickness was 30-60 μm, the thickness tolerance was ≤1 μm, the surface was free of oxidation, scratches, and pits, had a metallic luster, the surface roughness Ra ≤0.2 μm, and the flatness ≤0.01 mm. The probes obtained in Examples 1-3 all exhibited good current resistance, fatigue resistance, and wear resistance. Compared to Example 1, Comparative Example 1 uses a different method for preparing the ultrathin strip. This ultrathin strip suffers from significant losses in hardness and strength, and it lacks surface polishing, cleaning, and leveling. Probes prepared from this strip exhibit extreme instability in current-carrying capacity, bending count, and wear resistance tests. In contrast, Comparative Example 2, using ultrathin strips with different alloy compositions, shows significantly reduced hardness, strength, and conductivity. Probes prepared from this strip also exhibit significantly reduced current-carrying capacity, bending count, and wear resistance. Current resistance is evaluated based on the current-carrying capacity of the probe before significant failure. Fatigue resistance refers to the probe's ability to recover elasticity after bending, evaluated based on the number of bending cycles. Wear resistance is evaluated based on the number of friction cycles corresponding to 50% wear at the probe tip. In other words, significant probe failure includes, but is not limited to, a significant decrease in the probe's mechanical properties, severe deformation, and oxidation.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high-hardness, high-conductivity palladium-based alloy ultrathin strip, characterized in that, It is composed of the following metal raw materials in the following mass ratios: Pd 46%~51%, Cu 38.5%~42.5%, Ag 8.5%~12.5%, Ru 0.2%~3.0%, and Pt 0.1%~0.5%; The phase composition of the palladium-based alloy ultrathin strip mainly consists of Pd-Ag solid solution, Pd-Cu solid solution, CuPd ordered phase, and Cu3Pd. It consists of an ordered phase with an average grain size of 0.2~3μm; In the palladium-based alloy ultrathin strip, Ru exists independently in elemental form and is distributed discontinuously in a fibrous manner along the rolling direction in the macroscopic region. The diameter of the fibrous Ru is ≤400nm, and it is mainly 100nm and below. The preparation method of the high-hardness and high-conductivity palladium-based alloy ultrathin strip includes the following steps: casting, solution treatment, large deformation cold rolling, surface polishing and cleaning, and aging leveling treatment. The solution treatment and large deformation cold rolling process are carried out alternately, with no less than 3 alternating rolling times, and the total deformation of large deformation cold rolling is 80~97%; the solution treatment method is to keep the ingot obtained from the melting and casting process at 750~950℃ for 2 hours in a vacuum furnace, and then cool it with N2 gas at a cooling rate ≥15℃ / s. The aging and leveling treatment is a tension aging treatment, specifically, the strip is fixed on a leveling fixture, placed in a vacuum heat treatment furnace and kept at a certain temperature for a certain time, and then cooled with N2; the heating rate is ≥1℃ / s, the holding temperature is 350~420℃, the holding time is 0.5~3h, and the cooling rate is ≤3℃ / min.

2. The high-hardness, high-conductivity palladium-based alloy ultrathin strip according to claim 1, characterized in that, The palladium-based alloy ultrathin strip has a Vickers hardness of 450~500HV0.1, an electrical conductivity of 22~25%IACS, a tensile strength of 1100~1400MPa, an elastic modulus of 110~160GPa, a thickness of 30~60μm, a thickness tolerance of ≤1μm, and a surface free of oxidation, scratches, and pits, exhibiting a metallic luster and a surface roughness R. a ≤0.2μm, flatness ≤0.01mm.

3. The method for preparing the high-hardness, high-conductivity palladium-based alloy ultrathin strip according to claim 1, characterized in that, This includes processes such as casting, solution treatment, large deformation cold rolling, surface polishing and cleaning, and aging leveling. The solution treatment and large deformation cold rolling process are carried out alternately, with no less than 3 alternating rolling cycles, and the total deformation of the large deformation cold rolling is 80-97%. The solution treatment method is to keep the ingot obtained from the melting and casting process at 750-950℃ for 2 hours in a vacuum furnace, and then cool it with N2 gas at a cooling rate of ≥15℃ / s.

4. The method for preparing the high-hardness, high-conductivity palladium-based alloy ultrathin strip according to claim 3, characterized in that, The surface polishing and cleaning process is carried out by a three-stage brush wheel and an ultrasonic bath to continuously complete the rough polishing, medium polishing, precision polishing, cleaning and drying of the strip. The first-stage brush wheel is a nylon brush, and the second and third-stage brush wheels are velvet brushes. The polishing medium used in the first and second stages is 2.5~5μm diamond polishing slurry, and the polishing medium used in the third stage is 0.05~1.5μm diamond polishing slurry. The brush wheel speed is 50~1000r / min, and the strip winding and unwinding speed is 2~15m / min.

5. The method for preparing the high-hardness, high-conductivity palladium-based alloy ultrathin strip according to claim 3, characterized in that, The casting process employs at least two remelting steps, and the smelting process is protected by argon gas with a vacuum degree ≤10. -1 Pa, melting temperature 1200~1600℃, melt holding time 8~12min.

6. The method for preparing the high-hardness, high-conductivity palladium-based alloy ultrathin strip according to claim 3, characterized in that, The melting and casting process uses a graphite crucible and a graphite mold. The temperature of the cooling water inlet during casting is not higher than 20°C.

7. A probe with current resistance, fatigue resistance, and wear resistance based on the high-hardness, high-conductivity palladium-based alloy ultrathin strip according to any one of claims 1-2, characterized in that, The probe is prepared by laser cutting the palladium-based alloy ultrathin strip to obtain the target probe.

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