Silver-gold-palladium-chromium-indium-yttrium alloy and preparation method and application thereof

Abstract

The invention discloses a silver-gold-palladium-chromium-indium-yttrium alloy and a preparation method and application thereof, and belongs to the technical field of precise materials for semiconductor detection. The alloy comprises the following components in percentage by mass: 15%-20% of Au, 15%-18% of Pd, 8%-12% of Cr, 0.1%-0.3% of In, 0.2%-0.4% of Y and the balance of Ag. According to the preparation method, alloy component design is optimized, and an optimized preparation method is combined, so that a nano-to-micron Pd-Cr dispersed phase and Y element grain boundary segregation composite strengthened structure is formed through a multi-element synergistic strengthening mechanism, and the problems of In low-melting-point volatilization, columnar crystal length-diameter ratio control, high processing wire breakage rate and the like are solved; the alloy material with excellent comprehensive performance such as hardness, resistivity and machinability is obtained, meanwhile, the preparation cost of the alloy material is reduced, and the alloy material has better adaptability to a test probe subsequently matched with a process chip below 5nm.

Description

Technical Field

[0001] This invention belongs to the field of precision materials technology for semiconductor testing, and relates to a silver-gold-palladium-chromium-indium-yttrium alloy, its preparation method and application. Background Technology

[0002] As semiconductor chip manufacturing processes advance to 3-5nm and below, chip test probes face the dual challenges of performance bottlenecks and cost pressures in high-frequency, high-voltage, and high-density testing environments.

[0003] Current mainstream chip test probe materials suffer from insurmountable structural defects, failing to simultaneously meet the combined demands of high hardness, high conductivity, long lifespan, and low cost. For example, high-palladium-based alloys (Pd content 50-75wt%), represented by the Paliney series, generally have conductivity below 16% IACS, signal attenuation exceeding 30% at 10GHz, and Pd raw material costs are high, accounting for over 60% of the total probe cost. Extensive use of Pd leads to a sharp increase in alloy preparation costs, ultimately resulting in a significant increase in chip test probe manufacturing costs. Furthermore, their elongation is <2%, and the breakage rate during bending of ultrafine tips with a diameter ≤50μm exceeds 20%, leading to a large number of scrap products and further increasing probe manufacturing costs, while negatively impacting production efficiency and quality. Additionally, their hardness decreases by more than 15% at 80℃, making them unsuitable for high-density testing requirements.

[0004] Patent application CN201280076045.6 discloses an Ag-Pd-Cu-Co alloy for electrical and electronic equipment applications. However, its hardness only reaches a maximum of 450 HV. When used as a probe material, it results in limited probe insertion and extraction life, and is prone to problems such as difficulty in wire drawing and high brittleness during bending. Furthermore, its Pd content is 20-50 wt%, which, while lower than traditional Paliney series alloys, represents a smaller reduction, and the cost remains relatively high.

[0005] Tanaka Precious Metals' Pt-Pd-Ir-Ru-Rh pentagonal high-entropy alloy can achieve a hardness of over 450 HV. However, it uses more of the relatively expensive precious metals, making its raw material cost more than three times that of traditional Paliney series alloys. Furthermore, because it is prepared using powder metallurgy, it cannot achieve the oriented columnar crystal structure required for probes, making it difficult to draw ultrafine wires with small diameters. Simultaneously, its electrical conductivity is limited to below 15% IACS due to the multi-component solid solution treatment.

[0006] For example, patent application number 201780097805.4 discloses a precipitation-hardening Ag-Pd-Cu-In-B alloy, which can achieve a hardness of over 500 HV, but its resistivity is at a high level, all above 10 µΩ·cm. Furthermore, after the addition of boron (B), due to its small atomic radius (approximately 0.82 Å), it has poor compatibility with matrix metals such as Ag and Pd. During segregation, it tends to accumulate at grain boundaries, forming low-melting-point grain boundary phases or brittle intermetallic compounds (such as Ag3B and Pd4B) with the matrix elements. These phases are continuously distributed along the grain boundaries, causing the grain boundary continuity to be broken, leading to a sharp decrease in grain boundary bonding strength, ultimately resulting in grain boundary embrittlement and a high rate of wire breakage during cold working.

[0007] Therefore, it is necessary to provide a silver-gold-palladium-chromium-indium-yttrium alloy, its preparation method, and its application to fill the technological gap in the materials required for test probes of advanced process chips in terms of conductivity, hardness, cost, and processability. This will allow for the acquisition of an alloy material with excellent comprehensive performance, better meeting the comprehensive performance requirements of test probes, providing a feasible direction for the subsequent development of materials adapted to test probes of 5nm and below advanced process chips, and improving the adaptability of test probes in the testing of advanced process chips. Summary of the Invention

[0008] To overcome the problems in the prior art, this invention optimizes alloy composition design and process optimization to obtain alloy materials with superior hardness, resistivity, and machinability. Test probes made from these alloy materials exhibit longer service life, higher testing accuracy, and greater stability, making them more suitable for testing advanced chips at 5nm and below. Furthermore, this invention significantly reduces the amount of high-cost Pd used, thus lowering the alloy preparation cost.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution: The present invention proposes a silver-gold-palladium-chromium-indium-yttrium alloy, wherein the alloy composition by mass percentage includes: Au: 15%~20%, Pd: 15%~18%, Cr: 8%~12%, In: 0.1%~0.3%, Y: 0.2%~0.4%, and the balance is Ag.

[0010] The alloy material of this invention has a 50% to 150% higher electrical conductivity and a 30% to 40% lower cost compared to traditional Paliney series alloy materials.

[0011] The present invention also proposes a method for preparing the above alloy, the method comprising the following steps: (1) Raw material pretreatment: Weigh Ag, Au, Pd, Cr, In and Y raw materials according to the mass percentage of alloy composition, and after acid washing and purification, rinse and dry the raw materials.

[0012] (2) Preparation of Cr-Pd composite powder: The dried Cr raw material in step (1) is mixed and ball-milled with the Pd raw material to obtain Cr-Pd composite powder.

[0013] (3) Dual-temperature gradient melting: Under vacuum conditions, the dried Ag raw materials and Au raw materials in step (1) are melted, and then the Cr-Pd composite powder obtained in step (2) is added. After heating and holding for a certain time, the melt is cooled to a certain temperature, and then In raw materials and Y raw materials are added. After holding the temperature for a certain time, the melt is cooled to 500°C with the furnace, and argon gas is introduced to atmospheric pressure. Then the melt is cooled to room temperature with the furnace to obtain the ingot.

[0014] (4) Magnetic field-assisted directional solidification: The ingot obtained in step (3) is reheated and melted, and then cast. After casting, a temperature gradient is constructed on the melt in the manner of increasing temperature from bottom to top. At the same time, a DC magnetic field is applied to make the melt undergo directional solidification to obtain columnar crystal casting.

[0015] (5) Deformation processing: The columnar crystal casting obtained in step (4) is subjected to hot rolling and cold drawing in sequence, and pulse current annealing is performed during the cold drawing process to obtain alloy wire.

[0016] (6) Low-temperature plasma aging treatment: The alloy wire in step (5) is subjected to plasma aging treatment to obtain silver-gold-palladium-chromium-indium-yttrium alloy.

[0017] Preferably, in step (1), the pickling process is as follows: Ag raw material is ultrasonically cleaned with 5% nitric acid for 4 minutes, wherein the ultrasonic frequency is 40-45 kHz and the ultrasonic power is 150 W; Au and Pd raw materials are added to a mixed solution and soaked for 2.5 minutes, wherein the mixed solution is a mixture of 10% sulfuric acid and 3% hydrogen peroxide in a volume ratio of sulfuric acid:hydrogen peroxide = 3:1; Cr raw material is ultrasonically treated with 15% hydrochloric acid for 6 minutes, wherein the ultrasonic frequency is 40-45 kHz and the ultrasonic power is 180 W; In and Y raw materials are ultrasonically cleaned with a mixture of hydrofluoric acid and citric acid for 5-6 minutes, wherein the hydrofluoric acid concentration is 2%, the citric acid solution concentration is 5%, the volume ratio of hydrofluoric acid to citric acid solution is hydrofluoric acid:citric acid solution = 1:3, the ultrasonic frequency is 30-38 kHz, and the ultrasonic power is 140 W.

[0018] Preferably, in step (2), the ball-to-material ratio of the ball mill is 10~12:1, the ball milling speed is 300~350 r / min, and the ball milling time is 6~10 h.

[0019] Preferably, in step (3), the vacuum degree is ≤3×10⁻⁶. -4The melting temperature of Pa, Ag and Au raw materials is 1310~1330℃, and the holding time is 10min. After adding Cr-Pd composite powder, the melting temperature is increased to 1380~1400℃, and the holding time is 20~25min. During the holding time, the melt is stirred at a speed of 300~500r / min. When the melt cools down to 920~940℃, In and Y raw materials are added, and then the temperature is held for 15min.

[0020] Preferably, in step (4), the reheating melting temperature is 1450°C, and the mold preheating temperature is 460~490°C during casting.

[0021] Preferably, in step (4), the DC magnetic field strength is 0.2~0.3T and the temperature gradient is 10~12℃ / cm.

[0022] Preferably, in step (5), the hot rolling temperature is 780~800℃, the single-pass reduction is 30%, and the casting is repeatedly hot rolled into a 5mm diameter ingot. Then, the ingot is cold drawn, with three passes constituting one cold drawing process. The first pass has a deformation amount of 18%, the second pass has a deformation amount of 15%, and the third pass has a deformation amount of 12%. After each cold drawing process, the alloy material is subjected to pulse current annealing. During the pulse current annealing process, the pulse current density is 12~15A / mm. 2 The frequency is 60~70Hz, the annealing temperature is 260~280℃, the holding time is 25~30min, and the cold drawing and pulse current annealing treatment is repeated until the cast rod is drawn into a wire with a diameter of 0.1mm. This maintains the dislocation density at (2~3)×10⁻⁶. 10 cm -2 Horizontal. During the cold drawing process, a diamond die is used with a die cone angle of 8~10° to ensure that the residual stress on the wire surface does not exceed 50MPa.

[0023] Preferably, in step (6), during the plasma aging process, an Ar-H2 mixed gas with a volume ratio of Ar:H2=4:1 is introduced until the vacuum degree is 60Pa, the plasma aging power is 60~80W, the aging temperature is 160~170℃, the aging time is 1.5~2h, and the wire moving speed is 12mm / min.

[0024] This invention also proposes the application of the above-mentioned alloy in the fabrication of test probes for chips, particularly in the fabrication of test probes for advanced process chips at 5nm and below.

[0025] The beneficial effects of this invention are: 1. In the alloy of the present invention, Ag and Au form an infinitely miscible solid solution, which can not only effectively improve the oxidation resistance of the alloy, but also form different precipitated phases through alloying to produce a synergistic strengthening effect.

[0026] 2. In the alloy of the present invention, Pd and Cr form a nano- to micron-scale Pd-Cr dispersed phase as the core strengthening phase for alloy hardness enhancement, effectively improving the alloy hardness. At the same time, through reasonable control of the composition ratio, excessive Cr is avoided, which forms a brittle CrAg3 phase with Ag.

[0027] 3. In this invention, the amount of Y added is far lower than the stoichiometric ratio required for Y to form intermetallic compounds with Ag and Au, thus avoiding the formation of harmful phases due to excessive enrichment; it also ensures sufficient coverage of Y atoms at the grain boundaries, guaranteeing the uniformity and stability of the strengthening effect. Simultaneously, due to their inherent characteristics, Y atoms preferentially migrate to the grain boundaries, filling vacancies and dislocations to form a uniformly dispersed adsorption layer. This adsorption layer effectively inhibits grain coarsening by pinning grain boundary migration. Under this process, the alloy grain size is stably controlled at 5~8μm, while simultaneously enhancing grain boundary bonding, thereby optimizing the overall performance of the alloy.

[0028] 4. In the alloy of this invention, the difference in atomic radii between In and Ag forms a Cottrell atmosphere, which pins dislocations and improves the plasticity of the alloy. Combined with pulsed current annealing, it effectively improves the wire breakage rate of the alloy wire during cold drawing, controlling the wire breakage rate to below 5%.

[0029] 5. This invention solves the problem of segregation caused by the density difference between Cr and Pd by pre-preparing Cr-Pd composite powder, laying a good foundation for the subsequent formation of a uniform Pd-Cr dispersion-reinforced phase.

[0030] 6. This invention employs a dual-temperature gradient melting process, which promotes the full melting and mixing of Ag, Au, Cr, and Pd. At the same time, the temperature gradient reduces the diffusion distance between Pd and Cr atoms to below 5 μm, creating conditions for the formation of the Pd-Cr second phase. Furthermore, it effectively prevents In from volatilizing at high temperatures, thereby increasing the In recovery rate to over 95%.

[0031] 7. This invention utilizes magnetic field-assisted directional solidification to guide the precipitation of second phases such as Pd-Cr along a specific crystal orientation, forming Pd-Cr second phases with a size of 20-30 nm and a spacing of 50-80 nm, oriented along the magnetic field direction. This creates a synergistic effect of "dispersion strengthening + directional strengthening," which is beneficial for further enhancing the alloy's hardness, increasing it by 15%-20% compared to when the strengthening phase is randomly distributed. Simultaneously, the segregation of Y element at the grain boundaries enhances atomic migration through magnetic field induction, increasing the Y concentration at the grain boundaries to 8 times that of the Ag-Au-Pd-Cr-In matrix. This suppresses the lateral growth of columnar crystals, increasing the aspect ratio of columnar crystals from 5:1 without a magnetic field to 8-10:1, resulting in a synergistic effect of grain boundary toughening and columnar crystal directional strengthening.

[0032] 8. This invention effectively increases the dislocation density of the alloy by employing cold working and pulsed current annealing, thereby improving the alloy strength. Furthermore, by utilizing the Joule heating effect of pulsed current annealing, local rapid heating is achieved, and some dislocation entanglements are repaired through electromigration, retaining more than 70% of the effective dislocations. This maintains the alloy's high strength while preventing coarsening of the Pd-Cr second phase, which helps improve the alloy's machinability and reduce the wire breakage rate.

[0033] 9. This invention employs low-temperature plasma aging treatment to promote atomic diffusion on the alloy surface, refining the grain size from 50-100nm to 10-20nm. Simultaneously, H2 plasma can reduce any oxide film (such as Ag2O) present on the surface, enriching Au to form an anti-oxidation layer. Combined with the plastic effect of In, this stabilizes the contact resistance within the range of 30-38mΩ, and the resistance increase remains below 10% even after 50,000-100,000 insertion and removal cycles. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0035] Figure 2 Here is a metallographic diagram of the alloy in Example 1; Figure 3 This is a microhardness diagram of the alloy in Example 1.

[0036] Figure 4 The image shows the metallographic structure of the alloy in Example 2.

[0037] Figure 5 This is a microhardness diagram of the alloy in Example 2.

[0038] Figure 6 The image shows the metallographic structure of the alloy in Example 3.

[0039] Figure 7 This is a microhardness diagram of the alloy in Example 3. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0041] In this embodiment of the invention, unless otherwise specified, commercially available analytical grade chemical reagents were used in the experiments.

[0042] The alloy composition in the embodiments of the present invention is shown in Table 1.

[0043] Table 1 Example 1 This embodiment prepares the alloy according to the following steps: (1) Raw material preparation: Weigh the following materials according to the mass percentage in Table 1: Ag particles with a purity of 99.99%, Au flakes (thickness 0.1 mm), Pd powder (particle size 200 mesh), Cr blocks (purity 99.95%), In particles, and Y flakes (thickness 0.2 mm).

[0044] (2) Raw material pretreatment: Ag particles were ultrasonically cleaned with 5% nitric acid for 4 min at a frequency of 40 kHz and a power of 150 W. Au flakes and Pd powder were soaked in a mixed solution for 2.5 min, which was a mixture of 10% sulfuric acid and 3% hydrogen peroxide in a volume ratio of 3:1. Cr blocks were ultrasonically treated with 15% hydrochloric acid for 6 min at a frequency of 45 kHz and a power of 180 W. In particles and Y flakes were ultrasonically cleaned with a mixture of hydrofluoric acid and citric acid for 5 min at a concentration of 2% hydrofluoric acid and 5% citric acid in a volume ratio of 1:3. The ultrasonic frequency was 38 kHz and the power was 140 W. All raw materials were then rinsed with deionized water and vacuum dried at 80°C for 1 h. The raw materials were then stored in an argon glove box at a dew point of -45°C.

[0045] (3) Preparation of Cr-Pd composite powder: In an argon-protected environment, Cr blocks and Pd powder were mechanically alloyed. The ball-to-powder ratio of mechanical alloying was 10:1, the rotation speed was 300 r / min, and the time was 8 h. Cr-Pd composite powder with a particle size of 6-7 μm and a particle size distribution standard deviation ≤0.5 μm was obtained.

[0046] (4) Dual-temperature gradient melting: Ag particles and Au flakes are first added into a vacuum induction furnace, and the furnace cavity is evacuated to 2×10 -4Pa, Ag particles and Au flakes were heated to 1320℃ and held for 10 minutes until completely melted, with the Ag-Au melting stage maintained at 350 r / min; then Cr-Pd composite powder was added, the temperature was raised to 1390℃ and held for 22 minutes, with the melting stage maintained at 450 r / min; then the temperature was lowered to 930℃, In particles and Y flakes were added, and the temperature was held for another 15 minutes, with the melting stage maintained at 350 r / min and the vacuum degree maintained at 2×10 -4 Pa; Finally, after the alloy melt is cooled to 500°C in the furnace, argon gas is introduced into the furnace cavity to atmospheric pressure, and after cooling to room temperature, the ingot is removed.

[0047] (5) Magnetic field-assisted directional solidification: The ingot is reheated to 1450℃ to melt and cast into a graphite mold preheated to 480℃. The bottom of the graphite mold is water-cooled (water flow rate 1L / min). A temperature gradient of 11℃ / cm is constructed according to the principle of increasing temperature from bottom to top. At the same time, a DC magnetic field of 0.2T is applied (the mold is a rod mold, and the direction of the DC magnetic field is the same as the mold axis), so that the melt is cooled at a rate of 6℃ / min to obtain a columnar crystal length-to-diameter ratio of about 9:1.

[0048] (6) Cold working and pulse annealing: The cast rod is hot rolled to a diameter of 5 mm at 800℃, with a single-pass reduction of 30%. Then, the cast rod is cold drawn in multiple passes, with a deformation of 18% in the first pass, 15% in the second pass, and 12% in the third pass. After the above three cold drawing passes are completed, the wire is clamped with copper electrodes and pulsed current annealing is performed. The pulsed current annealing current density is 13 A / mm. 2 The frequency was 60Hz, the temperature was 260℃, the holding time was 28min, and the temperature was naturally cooled after holding. The above three drawing and pulse current annealing were repeated until the cast rod was drawn into a wire with a diameter of 0.1mm. After each round of drawing, the wire diameter was monitored in real time by a laser diameter gauge to ensure that the dimensional deviation was ≤±0.002mm.

[0049] (7) Low-temperature plasma aging: A 0.1 mm wire was placed in a plasma treatment instrument, and an Ar-H2 mixed gas was introduced into the plasma treatment instrument until the vacuum degree was 60 Pa. The volume ratio of Ar gas to H2 was Ar:H2=4:1. The plasma aging power was 60 W, the temperature was 160 °C, the aging time was 1.5 h, and the wire moving speed was 12 mm / min. A silver-gold-palladium-chromium-indium-yttrium alloy wire was obtained.

[0050] The alloy wire prepared in this embodiment was subjected to performance testing, and the results were as follows: the Vickers hardness of the wire was 501.53 HV, the contact resistance was 32 mΩ, and the resistivity was 4.079 µΩ·cm.

[0051] Example 2 This embodiment prepares the alloy according to the following steps: (1) Raw material preparation: Weigh the following materials according to the mass percentage in Table 1: Ag particles with a purity of 99.99%, Au flakes (thickness 0.1 mm), Pd powder (particle size 200 mesh), Cr blocks (purity 99.95%), In particles, and Y flakes (thickness 0.2 mm).

[0052] (2) Raw material pretreatment: Ag particles were ultrasonically cleaned with 5% nitric acid for 4 min at an ultrasonic frequency of 42 kHz and an ultrasonic power of 150 W. Au flakes and Pd powder were soaked in a mixed solution for 2.5 min, which was a mixture of 10% sulfuric acid and 3% hydrogen peroxide in a volume ratio of sulfuric acid:hydrogen peroxide = 3:1. Cr blocks were ultrasonically treated with 15% hydrochloric acid for 6 min at an ultrasonic frequency of 43 kHz and an ultrasonic power of 180 W. In particles and Y flakes were ultrasonically cleaned with a mixture of hydrofluoric acid and citric acid for 5 min at a hydrofluoric acid concentration of 2% and a citric acid solution concentration of 5%, with a volume ratio of hydrofluoric acid:citric acid solution = 1:3, an ultrasonic frequency of 35 kHz, and an ultrasonic power of 140 W. All raw materials were then rinsed with deionized water and vacuum dried at 80 ℃ for 1 h, and stored in an argon glove box at a dew point of -45 ℃.

[0053] (3) Preparation of Cr-Pd composite powder: In an argon-protected environment, Cr blocks and Pd powder were mechanically alloyed. The ball-to-powder ratio of mechanical alloying was 12:1, the rotation speed was 350 r / min, and the time was 10 h. Cr-Pd composite powder with a particle size of 7~8 μm and a particle size distribution standard deviation ≤0.5 μm was obtained.

[0054] (4) Dual-temperature gradient melting: Ag particles and Au flakes are first added to a vacuum induction furnace, and the furnace cavity is evacuated to 2.5 × 10⁻⁶. -4 Pa, Ag particles and Au flakes were heated to 1330℃ and held for 10 minutes until completely melted, with the Ag-Au melting stage maintained at 400 r / min; then Cr-Pd composite powder was added, the temperature was raised to 1400℃ and held for 25 minutes, with the melting stage maintained at 500 r / min; then the temperature was lowered to 930℃, In particles and Y flakes were added, and the temperature was held for another 15 minutes, with the melting stage maintained at 400 r / min and the vacuum degree maintained at 2.5 × 10⁻⁶. -4 Pa; Finally, after the alloy melt is cooled to 500°C in the furnace, argon gas is introduced into the furnace cavity to atmospheric pressure, and after cooling to room temperature, the ingot is removed.

[0055] (5) Magnetic field-assisted directional solidification: The ingot is reheated to 1450℃ to melt and cast into a graphite mold preheated to 490℃. The bottom of the graphite mold is water-cooled (water flow rate 1L / min). A temperature gradient of 12℃ / cm is constructed according to the principle of increasing temperature from bottom to top. At the same time, a DC magnetic field of 0.25T is applied (the mold is a rod mold, and the direction of the DC magnetic field is the same as the mold axis), so that the melt is cooled at a rate of 7℃ / min to obtain a columnar crystal with an aspect ratio of about 10:1.

[0056] (6) Cold working and pulse annealing: The cast rod is hot rolled to a diameter of 5 mm at 790℃, with a single-pass reduction of 30%. Then, the cast rod is cold drawn in multiple passes, with a deformation of 18% in the first pass, 15% in the second pass, and 12% in the third pass. After the above three cold drawing passes are completed, the wire is clamped with copper electrodes and subjected to pulse current annealing with a pulse current density of 14 A / mm. 2 The frequency was 65Hz, the temperature was 270℃, the holding time was 30min, and the temperature was naturally cooled after holding. The above three drawing and pulse current annealing were repeated until the cast rod was drawn into a wire with a diameter of 0.1mm. After each round of drawing, the wire diameter was monitored in real time by a laser diameter gauge to ensure that the dimensional deviation was ≤±0.002mm.

[0057] (7) Low-temperature plasma aging: A 0.1 mm wire was placed in a plasma treatment instrument, and an Ar-H2 mixed gas was introduced into the plasma treatment instrument until the vacuum degree was 60 Pa. The volume ratio of Ar to H2 was Ar:H2=4:1. The plasma aging power was 70 W, the temperature was 165 °C, the aging time was 1.75 h, and the wire moving speed was 12 mm / min. A silver-gold-palladium-chromium-indium-yttrium alloy wire was obtained.

[0058] The alloy wire prepared in this embodiment was subjected to performance testing, and the results were as follows: the Vickers hardness of the wire was 495.18 HV, the contact resistance was 35 mΩ, and the resistivity was 4.681 µΩ·cm.

[0059] Example 3 This embodiment prepares the alloy according to the following steps: (1) Raw material preparation: Weigh the following materials according to the mass percentage in Table 1: Ag particles with a purity of 99.99%, Au flakes (thickness 0.1 mm), Pd powder (particle size 200 mesh), Cr blocks (purity 99.95%), In particles, and Y flakes (thickness 0.2 mm).

[0060] (2) Raw material pretreatment: Ag particles were ultrasonically cleaned with 5% nitric acid for 4 min at a frequency of 45 kHz and a power of 150 W. Au flakes and Pd powder were soaked in a mixed solution for 2.5 min, which was a mixture of 10% sulfuric acid and 3% hydrogen peroxide in a volume ratio of 3:1. Cr blocks were ultrasonically treated with 15% hydrochloric acid for 6 min at a frequency of 40 kHz and a power of 180 W. In particles and Y flakes were ultrasonically cleaned with a mixture of hydrofluoric acid and citric acid for 5.5 min at a volume ratio of 1:3 (2% hydrofluoric acid, 5% citric acid, 30 kHz, and 140 W). All raw materials were then rinsed with deionized water and vacuum dried at 80°C for 1 h, and stored in an argon glove box at a dew point of -45°C.

[0061] (3) Preparation of Cr-Pd composite powder: In an argon-protected environment, Cr blocks and Pd are mechanically alloyed. The ball-to-material ratio of mechanical alloying is 11:1, the rotation speed is 320 r / min, and the time is 6 h. Cr-Pd composite powder with a particle size of 5~10 μm is obtained by sieving, and the standard deviation of particle size distribution is ≤1 μm.

[0062] (4) Dual-temperature gradient melting: Ag particles and Au sheets are first added into a vacuum induction furnace, and the furnace cavity is evacuated to 3×10 -4 Pa, Ag particles and Au flakes were heated to 1310℃ and held for 10 minutes until completely melted, with the Ag-Au melting stage maintained at 300 r / min; then Cr-Pd composite powder was added, the temperature was raised to 1380℃ and held for 20 minutes, with the melting stage maintained at 400 r / min; then the temperature was lowered to 920℃, In particles and Y flakes were added, and the temperature was held for another 15 minutes, with the melting stage maintained at 300 r / min and the vacuum degree maintained at 3×10 -4 Pa; Finally, after the alloy melt is cooled to 500°C in the furnace, argon gas is introduced into the furnace cavity to atmospheric pressure, and after cooling to room temperature, the ingot is removed.

[0063] (5) Magnetic field-assisted directional solidification: The ingot is reheated to 1450℃ to melt and cast into a graphite mold preheated to 460℃. The bottom of the graphite mold is water-cooled (water flow rate 1L / min). A temperature gradient of 10℃ / cm is constructed according to the principle of increasing temperature from bottom to top. At the same time, a DC magnetic field of 0.3T is applied (the mold is a rod mold, and the direction of the DC magnetic field is the same as the mold axis), so that the melt is cooled at a rate of 5℃ / min to obtain a columnar crystal length-to-diameter ratio of about 9:1.

[0064] (6) Cold working and pulse annealing: The cast rod is hot rolled to a diameter of 5 mm at 780℃, with a single-pass reduction of 30%. Then, the cast rod is cold drawn in multiple passes, with a deformation of 18% in the first pass, 15% in the second pass, and 12% in the third pass. After the above three cold drawing passes are completed, the wire is clamped with copper electrodes and subjected to pulse current annealing with a pulse current density of 12 A / mm. 2 The frequency was 70Hz, the temperature was 280℃, the holding time was 25min, and after holding, it was naturally cooled. The above three drawing and pulse current annealing were repeated until the cast rod was drawn into a wire with a diameter of 0.1mm.

[0065] (7) Low-temperature plasma aging: A 0.1 mm wire was placed in a plasma treatment instrument, and an Ar-H2 mixed gas was introduced into the plasma treatment instrument until the vacuum degree was 60 Pa. The volume ratio of Ar to H2 was Ar:H2=4:1. The plasma aging power was 80 W, the temperature was 170 °C, the aging time was 2 h, and the wire moving speed was 12 mm / min. A silver-gold-palladium-chromium-indium-yttrium alloy wire was obtained.

[0066] The alloy wire prepared in this embodiment was subjected to performance testing, and the results were as follows: the Vickers hardness of the wire was 489.37 HV, the contact resistance was 33 mΩ, and the resistivity was 4.328 µΩ·cm.

[0067] pass Figure 2 It can be seen that in the alloy prepared by this invention, the strengthening phase is in the form of irregular short rods or granules, with uniform size and no obvious agglomeration or elongated segregation. The matrix is ​​continuous and there is no coarse second phase, indicating that this invention has successfully solved the density segregation problem, enabling the uniform formation of the Pd-Cr second phase, and achieving its dispersed distribution and short-range order, laying the foundation for strengthening. Judging from the grain profile, the grain size is about 5-8 μm, the grain boundaries are clear and there are no obvious brittle phase enrichment characteristics, and the density of the Pd-Cr second phase at the grain boundaries is slightly higher than that in the grains, indicating that the Y element grain boundary segregation effectively inhibits grain coarsening, the Cr composition is reasonably controlled to avoid brittle phases, and the Pd-Cr second phase is enriched at the grain boundaries, which, combined with Y, achieves grain boundary strengthening and toughening.

[0068] pass Figure 3 As can be seen, the indentation is a regular rhombus shape with uniform diagonal length, no chipping, intact edges and corners, and no obvious crack propagation or excessive plastic deformation depressions around it. This reflects the good uniformity of the alloy hardness, with no local soft spots or hard spots. The Vickers hardness is 501.53 HV, proving the effective synergistic effect of Pd-Cr dispersion strengthening and fine grain strengthening. The absence of chipping in the indentation indicates strong grain boundary bonding, Y element strengthening the grain boundaries and the absence of brittle phases. The alloy has a good balance of strength and toughness, which can reduce the wire breakage rate and improve plasticity. The experimental results are consistent with the control of strengthening phases and grain boundary strengthening effects of the pre-prepared composite powder and magnetic field directional solidification processes in this invention.

[0069] pass Figure 4 It can be seen that the strengthening phase is in the form of irregular particles or short rods, diffusely distributed in the gold matrix, without obvious agglomeration or segregation; the matrix is ​​continuous, and no coarse second phase was found. Based on the scale bar, the grain size is in the range of 5-8 μm, with clear grain boundaries and no obvious defects caused by the enrichment of brittle phases. Furthermore, the density of the Pd-Cr second phase at the grain boundaries is slightly higher than that within the grains. This indicates that the present invention effectively solves the density segregation problem, enabling the uniform formation of the Pd-Cr second phase; the segregation of Y elements at grain boundaries can suppress grain coarsening, achieving fine grains, while avoiding excessive Cr formation of brittle phases. The enrichment of the Pd-Cr second phase at grain boundaries and its synergistic effect with Y enhance the grain boundary bonding force, laying the foundation for alloy strengthening.

[0070] pass Figure 5 As can be seen, the indentations in the image are regular rhomboid shapes with intact edges and corners, without any chipping or excessive deformation, and the diagonal length is uniform. This indicates that the alloy has good uniformity in hardness, with no local soft or hard spots. The Vickers hardness is 495.18 HV, demonstrating the synergistic effect of Pd-Cr dispersion strengthening and grain refinement strengthening. The absence of chipping in the indentations reflects strong grain boundary bonding, with Y element strengthening the grain boundaries and the absence of brittle phases. The alloy exhibits a good balance of strength and toughness, effectively reducing wire breakage and improving plasticity. Furthermore, the control of In content and pulse annealing parameters makes the pinning effect of the Cotillard atmosphere on dislocations more significant, which is beneficial to improving the alloy's plasticity.

[0071] pass Figure 6 It can be seen that the strengthening phase, in the form of irregular particles and short rods, is diffusely distributed in the golden matrix without obvious agglomeration or segregation, ensuring the continuity of the matrix and preventing the appearance of coarse second phases. Using a scale, the grain size is maintained in the 5-8 μm range, with clearly distinguishable grain boundaries. There are no significant defects caused by the enrichment of brittle phases, and the density of the Pd-Cr phase at the grain boundaries is slightly higher than that in the inner grain region. This microstructure clearly demonstrates that the present invention effectively solves the problem of density segregation, promoting the uniform formation of the Pd-Cr second phase. The grain boundary segregation effect of Y element successfully suppresses grain coarsening, achieving the goal of fine grains, while avoiding excessive Cr formation of brittle Pd-Cr second phase. The enrichment of the Pd-Cr second phase at the grain boundaries, in conjunction with Y, enhances the grain boundary bonding force, laying a solid foundation for alloy strengthening.

[0072] pass Figure 7As can be seen, the indentation exhibits a regular rhomboid shape with intact edges and corners, without any chipping or excessive deformation, and the diagonal length is uniform. This indentation characteristic indicates that the alloy possesses good hardness uniformity, with no local soft or hard spots. The Vickers hardness is 489.37 HV, strongly demonstrating the synergistic effect of Pd-Cr dispersion strengthening and grain refinement strengthening. The absence of chipping in the indentation reflects strong grain boundary bonding, indicating a significant strengthening effect of Y element on grain boundaries, and the absence of brittle phase formation, resulting in a good balance between strength and toughness in the alloy, effectively reducing wire breakage rate and improving plasticity.

[0073] In summary, this invention, through optimized alloy composition design and process optimization, successfully obtained an alloy material with excellent hardness of not less than 485 HV, resistivity not exceeding 5 µΩ·cm, and superior machinability. Using this alloy material to fabricate test probes not only improves their lifespan, testing accuracy, and stability, but also enhances their adaptability to testing chips manufactured using processes below 5nm. Furthermore, it significantly reduces alloy preparation costs, thereby contributing to lower test probe manufacturing costs.

[0074] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and in detail without departing from the scope defined by the claims of the present invention.

Claims

1. A silver-gold-palladium-chromium-indium-yttrium alloy, characterized in that: The alloy composition, by mass percentage, includes: Au: 15%~20%, Pd: 15%~18%, Cr: 8%~12%, In: 0.1%~0.3%, Y: 0.2%~0.4%, with the balance being Ag.

2. The method for preparing a silver-gold-palladium-chromium-indium-yttrium alloy according to claim 1, characterized in that: The preparation method includes the following steps: (1) Raw material pretreatment: Weigh Ag, Au, Pd, Cr, In and Y raw materials according to the mass percentage of alloy composition, and after acid washing and purification, rinse and dry the raw materials; (2) Preparation of Cr-Pd composite powder: The dried Cr raw material in step (1) is mixed and ball-milled with the Pd raw material to obtain Cr-Pd composite powder; (3) Dual-temperature gradient melting: Under vacuum conditions, the dried Ag raw materials and Au raw materials in step (1) are melted, and then the Cr-Pd composite powder obtained in step (2) is added. After heating and holding for a certain time, the melt is cooled to a certain temperature, and then In raw materials and Y raw materials are added. After holding the temperature for a certain time, the melt is cooled to 500°C with the furnace, and argon is introduced to atmospheric pressure. Then the melt is cooled to room temperature with the furnace to obtain the ingot. (4) Magnetic field-assisted directional solidification: The ingot obtained in step (3) is reheated and melted, and then cast. After casting, a temperature gradient is constructed on the melt in the manner of increasing temperature from bottom to top. At the same time, a DC magnetic field is applied to make the melt undergo directional solidification to obtain columnar crystal casting. (5) Deformation processing: The columnar crystal casting obtained in step (4) is subjected to hot rolling and cold drawing in sequence, and pulse current annealing is performed during the cold drawing process to obtain alloy wire. (6) Low-temperature plasma aging treatment: The alloy wire in step (5) is subjected to plasma aging treatment to obtain silver-gold-palladium-chromium-indium-yttrium alloy.

3. The preparation method according to claim 2, characterized in that: In step (1), the pickling process is as follows: Ag raw material is ultrasonically cleaned with 5% nitric acid for 4 minutes, with an ultrasonic frequency of 40-45 kHz and an ultrasonic power of 150 W; Au and Pd raw materials are soaked in a mixed solution for 2.5 minutes, wherein the mixed solution is a mixture of 10% sulfuric acid and 3% hydrogen peroxide in a volume ratio of sulfuric acid:hydrogen peroxide = 3:1; Cr raw material is ultrasonically treated with 15% hydrochloric acid for 6 minutes, with an ultrasonic frequency of 40-45 kHz and an ultrasonic power of 180 W; In and Y raw materials are ultrasonically cleaned with a mixture of hydrofluoric acid and citric acid for 5-6 minutes, wherein the hydrofluoric acid concentration is 2%, the citric acid solution concentration is 5%, the volume ratio of hydrofluoric acid to citric acid solution is hydrofluoric acid:citric acid solution = 1:3, the ultrasonic frequency is 30-38 kHz, and the ultrasonic power is 140 W.

4. The preparation method according to claim 2, characterized in that: In step (2), the ball-to-material ratio of the ball mill is 10~12:1, the ball milling speed is 300~350 r / min, and the ball milling time is 6~10 h.

5. The preparation method according to claim 2, characterized in that: In step (3), the vacuum degree is ≤3×10 -4 The melting temperature of Pa, Ag and Au raw materials is 1310~1330℃, and the holding time is 10min. After adding Cr-Pd composite powder, the melting temperature is increased to 1380~1400℃, and the holding time is 20~25min. During the holding time, the melt is stirred at a speed of 300~500r / min. When the melt cools down to 920~940℃, In and Y raw materials are added, and then the temperature is held for 15min.

6. The preparation method according to claim 2, characterized in that: In step (4), the reheating melting temperature is 1450℃, and the mold preheating temperature is 460~490℃ during casting.

7. The preparation method according to claim 2, characterized in that: In step (4), the DC magnetic field strength is 0.2~0.3T and the temperature gradient is 10~12℃ / cm.

8. The preparation method according to claim 2, characterized in that: In step (5), the hot rolling temperature is 780~800℃, the single-pass reduction is 30%, and the casting is repeatedly hot rolled into a 5mm diameter ingot. Then, the ingot is cold drawn, with three passes constituting one cold drawing process. The first pass has a deformation amount of 18%, the second pass has a deformation amount of 15%, and the third pass has a deformation amount of 12%. After each cold drawing process, the alloy material is subjected to pulse current annealing. During the pulse current annealing process, the pulse current density is 12~15A / mm. 2 The frequency is 60~70Hz, the annealing temperature is 260~280℃, the holding time is 25~30min, and the cold drawing and pulse current annealing treatment are repeated until the cast rod is drawn into a wire with a diameter of 0.1mm.

9. The preparation method according to claim 2, characterized in that: In step (6), during the plasma aging process, an Ar-H2 mixed gas with a volume ratio of Ar:H2=4:1 is introduced until the vacuum degree is 60Pa, the plasma aging power is 60~80W, the aging temperature is 160~170℃, the aging time is 1.5~2h, and the wire moving speed is 12mm / min.

10. The application of the silver-gold-palladium-chromium-indium-yttrium alloy as described in claim 1 in the fabrication of test probes for chips.

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