Method for manufacturing cu-ag alloy wire material, cu-ag alloy wire material manufactured thereby, and probe pin for inspecting electric / electronic component obtained using cu-ag alloy wire material

Abstract

Provided are: a method for manufacturing a Cu-Ag alloy wire material, the method being characterized by including the following steps in the stated order; and a Cu-Ag alloy wire material manufactured by the method. Step 1: a metal rod is obtained by melting metal raw materials that have been blended so that, excluding inevitable impurities, the composition is 10.0 wt% to 30.0 wt% Ag and the remainder Cu. Step 2 to step 4: cold drawing and heat treatment are repeated three times while gradually increasing the rate of cross-sectional reduction between before and after processing. Step 5 to step 7: the cold drawing and the heat treatment are repeated three times so that the rate of cross-sectional reduction between before and after processing becomes larger than that in step 2 to step 4. Step 8: a Cu-Ag alloy wire material having a diameter of 0.1 mm or less is obtained by subjecting the metal rod to cold drawing such that the rate of cross-sectional reduction is 99.0% to 99.9999%.

Description

Method for manufacturing Cu-Ag alloy wire, Cu-Ag alloy wire manufactured by this method, and probe pin for inspecting electrical / electronic components obtained using Cu-Ag alloy wire

[0001] The invention of the present application relates to a method for manufacturing a Cu—Ag alloy wire, a Cu—Ag alloy wire manufactured by this manufacturing method, and a probe pin for inspecting electric / electronic components obtained by using this Cu—Ag alloy wire.

[0002] In recent years, semiconductor devices have been increasing in pin count and pitch narrower to meet market needs for higher functionality and performance. Accordingly, there is a demand for ultra-thin probe pins used in probe cards and contact probes for testing these devices. However, when conventional probe pins are simply made ultra-thin, they tend to lack strength and become unusable for repeated use.

[0003] One method for improving the strength of probe pins while maintaining high conductivity is to adjust the type and content of metals that make up the wire for the probe pin. Patent Document 1 discloses a "high-strength, high-conductivity copper alloy characterized by containing 4 to 32 at% Ag in Cu." According to Table 1 of the same document, the copper alloy in Patent Document 1 has a tensile strength of 85.1 kg / mm ２ ~99 kg / mm ２ (834 MPa to 970 MPa), and the conductivity is 78.4 IACS% to 84.8 IACS%.

[0004] Another possible method is to use the copper alloy composition of Patent Document 1 and then further improve the manufacturing process of the wire for probe pins. Patent Document 2 discloses a method for manufacturing a Cu-Ag alloy wire, characterized by "repeat- ing at least twice in sequence a step of cold working a cast rod obtained by continuously casting a Cu-based alloy containing 10 to 20 atomic % of Ag, with the remainder being Cu and unavoidable impurities, with an area reduction of 95% or more, and a step of heat treating the rod at a temperature of 450 to 550°C for 1 to 20 hours, and then cold working with an area reduction of 90% or more." The tensile strength of the Cu-Ag alloy wire manufactured by the manufacturing method of Patent Document 2 is 95 kgf / mm ２~102kgf / mm ２ (931 MPa to 1000 MPa), and the conductivity is 80 IACS% to 85 IACS%.

[0005] Furthermore, Patent Document 3 discloses a method for manufacturing a Cu-Ag alloy conductor, characterized in that "a cast rod obtained by continuously casting a Cu-based alloy containing 10 to 20 atomic % of Ag, with the remainder being Cu and unavoidable impurities, is subjected to heat treatment at a temperature of 450 to 500°C for 10 to 20 hours, and then subjected to cold working with an area reduction rate of 95% or more." The tensile strength of the Cu-Ag alloy conductor manufactured by the manufacturing method of Patent Document 3 is 110 kgf / mm ２ ~126kgf / mm ２ (1078 MPa to 1235 MPa), and the conductivity is 65 IACS% to 72 IACS%.

[0006] Japanese Unexamined Patent Publication No. 4-120227 Japanese Unexamined Patent Publication No. 6-103809 Japanese Unexamined Patent Application No. 6-93399

[0007] However, the copper alloy of Patent Document 1, the Cu—Ag alloy wire of Patent Document 2, and the Cu—Ag alloy conductor of Patent Document 3 still lack strength to be used as a wire for a probe pin with an ultra-fine wire diameter of, for example, 0.1 mm or less. Therefore, the market continues to demand a metal wire for inspecting electrical and electronic components that has both high conductivity and strength.

[0008] As a result of extensive research, the inventors of the present application have achieved the above-mentioned object by adopting the following means.

[0009] A. Manufacturing Method of Cu—Ag Alloy Wire The manufacturing method of Cu—Ag alloy wire according to the present application is characterized by comprising the following steps 1 to 8 in order.

[0010] Step 1: A metal rod is obtained by melting a metal raw material blended to have a composition of 10.0 wt% to 30.0 wt% Ag, excluding inevitable impurities, and the remainder Cu. Step 2: Cold wire drawing is performed so that the cross-sectional area reduction rate before and after processing is 15% to 25%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere. Step 3: Cold wire drawing is performed so that the cross-sectional area reduction rate before and after processing is 25% to 35%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere. Step 4: Cold wire drawing is performed so that the cross-sectional area reduction rate before and after processing is 30% to 40%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere. Step 5: Cold wire drawing or cold wire drawing and shaving is performed so that the cross-sectional area reduction rate before and after processing is 80% to 90%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere. Step 6: Cold wire drawing or cold wire drawing and shaving is performed so that the area reduction rate before and after processing is 85% to 95%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere.Step 7: Cold wire drawing or cold wire drawing and shaving is performed so that the area reduction rate before and after processing is 80% to 90%, followed by heat treatment in a slightly reducing gas or inert gas atmosphere.Step 8: Cold wire drawing is performed so that the area reduction rate for the metal rod is 99.0% to 99.9999%, obtaining a Cu-Ag alloy wire having a diameter of 0.1 mm or less, containing 10.0 wt% to 30.0 wt% Ag, with the balance consisting of Cu and unavoidable impurities.

[0011] In the method for producing a Cu—Ag alloy wire according to the present application, it is preferable that the heat treatments in steps 2 and 3 are carried out at 400° C. to 500° C. for 0.5 to 3 hours, the heat treatment in step 4 is carried out at 350° C. to 450° C. for 0.5 to 3 hours, the heat treatment in step 5 is carried out at 300° C. to 400° C. for 0.5 to 3 hours, the heat treatment in step 6 is carried out at 250° C. to 350° C. for 0.5 to 3 hours, and the heat treatment in step 7 is carried out at 230° C. to 330° C. for 0.5 to 3 hours.

[0012] B. Cu—Ag Alloy Wire The Cu—Ag alloy wire according to the present application is manufactured by the above-described method for manufacturing a Cu—Ag alloy wire according to the present application, and is characterized by having a tensile strength of 1600 MPa or more.

[0013] The Cu—Ag alloy wire according to the present application preferably has an electrical conductivity of 46.0 IACS% or more, a resistivity of 4.0 μΩ·cm or less, and a Vickers hardness of 360 HV or more.

[0014] C. Probe Pin for Inspecting Electrical and Electronic Components The probe pin for inspecting electrical and electronic components according to the present application is characterized by being obtained using the Cu—Ag alloy wire rod according to the present application described above.

[0015] The present invention provides a method for manufacturing a Cu—Ag alloy wire having both high electrical conductivity and strength, which can be suitably used as a wire for an ultra-fine probe pin with a diameter of 0.1 mm or less, and a Cu—Ag alloy wire manufactured by this manufacturing method. The present invention also provides a probe pin for inspecting electrical and electronic components, which can be suitably used for continuity inspection of semiconductor devices with a large number of pins and a narrow pitch.

[0016] A. Manufacturing Method of Cu—Ag Alloy Wire The manufacturing method of Cu—Ag alloy wire according to the present application is characterized by comprising the following steps 1 to 8 in order. By satisfying the above requirements, the manufacturing method of Cu—Ag alloy wire according to the present application can manufacture Cu—Ag alloy wire having high strength suitable for use as a wire for an ultra-fine probe pin having a diameter of 0.1 mm or less while maintaining the high conductivity required for a probe pin used in inspecting electrical and electronic components. In consideration of market demands and the results of various tests conducted during development, the specific value of "high conductivity required for a probe pin used in inspecting electrical and electronic components" is assumed to be 46.0 IACS% or more, and the specific value of "high strength suitable for use as a wire for an ultra-fine probe pin having a diameter of 0.1 mm or less" is assumed to be a tensile strength of 1600 MPa or more. The details of each step are explained below.

[0017] Step 1: A metal rod is obtained by melting metal raw materials blended to have a composition of 10.0 wt % to 30.0 wt % Ag, with the remainder being Cu, excluding unavoidable impurities.

[0018] The Cu—Ag alloy wire to be produced by the manufacturing method of the present application is a Cu—Ag alloy wire having a diameter of 0.1 mm or less, containing 10.0 wt% to 30.0 wt% Ag, with the remainder consisting of Cu and unavoidable impurities, as described in step 8. Therefore, the metal raw material used in step 1 also has the same composition. Here, if the Ag content in the metal raw material in step 1 is less than 10.0 wt%, the electrical conductivity of the Cu—Ag alloy wire obtained in step 8 tends to decrease, making it unsuitable for use as a probe pin for inspecting electrical and electronic components, which is undesirable. On the other hand, if the Ag content in the metal raw material in step 1 exceeds 30.0 wt%, the workability of the Cu—Ag alloy decreases, causing problems such as breakage during steps 2 to 8, making it difficult to process the Cu—Ag alloy into an ultrafine wire having a diameter of 0.1 mm or less, which is undesirable.

[0019] In step 1, a metal raw material having the above composition is melted to obtain a metal rod. Conventional melting methods and conditions may be used in step 1, and there are no particular limitations. However, the diameter of the metal rod obtained after melting (the length and width in the case of a rectangular shape) is preferably 10 mm to 30 mm. If the diameter of the metal rod is less than 10 mm, the degree of working (i.e., "working degree η=ln(A ０ / A １ ), but A ０ is the cross-sectional area of ​​the metal rod in step 1, A １The value calculated as the "cross-sectional area of ​​the Cu—Ag alloy wire in step 8" is insufficient, and a Cu—Ag alloy wire having the target strength (tensile strength of 1600 MPa or more) tends to be insufficient, which is undesirable. On the other hand, even if the diameter of the metal rod exceeds 30 mm, the conditions for the cold wire drawing and heat treatment (or the combination of cold wire drawing, shaving, and heat treatment) performed in the subsequent steps must be changed and the number of these steps must be further increased, which tends to reduce productivity, which is undesirable. Examples of methods for melting the metal raw material include continuous casting and melting in a vacuum or in an inert gas. When melting in a vacuum or in an inert gas is employed, it is also preferable to perform a facing process after melting in order to remove impurities present near the surface. In this case, the preferred numerical range of the diameter of the metal rod (10 mm to 30 mm) mentioned above includes the facing process (i.e., the "preferable numerical range of the diameter of the metal rod obtained after melting and facing process").

[0020] Step 2: After cold drawing so that the cross-sectional area reduction rate before and after processing is 15% to 25%, heat treatment is performed in a slightly reducing gas or inert gas atmosphere. Step 3: After cold drawing so that the cross-sectional area reduction rate before and after processing is 25% to 35%, heat treatment is performed in a slightly reducing gas or inert gas atmosphere. Step 4: After cold drawing so that the cross-sectional area reduction rate before and after processing is 30% to 40%, heat treatment is performed in a slightly reducing gas or inert gas atmosphere.

[0021] In these steps 2 to 4, the cold wire drawing and heat treatment are repeated multiple times while gradually increasing the cross-sectional area reduction rate before and after processing (i.e., (cross-sectional area of ​​Cu—Ag alloy before processing—cross-sectional area of ​​Cu—Ag alloy after processing) ÷ cross-sectional area of ​​Cu—Ag alloy before processing × 100). By adopting a method of sequentially performing these steps 2 to 4 and steps 5 to 7 described below, in step 8, a Cu—Ag alloy wire having a tensile strength of 1600 MPa or more, which is an indicator of "high strength suitable for use as a wire for an ultra-fine probe pin with a diameter of 0.1 mm or less," can be obtained.

[0022] The methods and conditions for the cold wire drawing and heat treatment in steps 2 to 4 may be conventionally known and are not particularly limited, but it is preferable that the heat treatments in steps 2 and 3 are carried out at 400°C to 500°C for 0.5 to 3 hours, and that the heat treatment in step 4 is carried out at 350°C to 450°C for 0.5 to 3 hours. The types of atmospheric gases for carrying out the heat treatments in steps 2 to 4 include a slightly reducing gas of 95% nitrogen and 5% hydrogen, and inert gases such as helium and argon.

[0023] Here, the heat treatments performed in steps 2 to 4 are stress relief annealing operations performed to relieve stress. Therefore, considering the composition of the metal raw material and the diameter of the metal rod after each cold wire drawing (the length in both the vertical and horizontal directions when cold wire drawing into a rectangular shape), if the heat treatment temperatures in steps 2 and 3 are less than 400°C, the stress relief effect is insufficient, and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8, which is undesirable. Similarly, if the heat treatment temperature in step 4 is less than 350°C, the stress relief effect is insufficient, and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8, which is undesirable. On the other hand, if the heat treatment temperature in steps 2 and 3 exceeds 500°C, the crystal grain size of the Cu—Ag alloy will excessively increase, and the hardness of the Cu—Ag alloy wire obtained in step 8 will tend to decrease, which is undesirable. Similarly, if the temperature of the heat treatment in step 4 exceeds 450°C, the size of the crystal grains of the Cu—Ag alloy will increase excessively, and the hardness of the Cu—Ag alloy wire obtained in step 8 will tend to decrease, which is not preferable.

[0024] Furthermore, if the heat treatment time in steps 2 to 4 is less than 0.5 hours, the stress relief effect is insufficient, and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8, which is not preferable. On the other hand, if the heat treatment time in steps 2 to 4 exceeds 3 hours, the stress relief effect is not significantly improved, and productivity simply decreases, which is not preferable.

[0025] Step 5: After cold wire drawing or cold wire drawing and shaving, heat treatment is performed in a slightly reducing gas or inert gas atmosphere so that the area reduction rate before and after processing is 80% to 90%. Step 6: After cold wire drawing or cold wire drawing and shaving, heat treatment is performed in a slightly reducing gas or inert gas atmosphere so that the area reduction rate before and after processing is 85% to 95%. Step 7: After cold wire drawing or cold wire drawing and shaving, heat treatment is performed in a slightly reducing gas or inert gas atmosphere so that the area reduction rate before and after processing is 80% to 90%.

[0026] In these steps 5 to 7, cold wire drawing and heat treatment (or cold wire drawing, shaving, and heat treatment) are repeated multiple times so that the cross-sectional area reduction rate before and after processing is 80% to 95%, which is higher than that of steps 2 to 4 described above. By adopting a method of sequentially performing steps 2 to 4 and steps 5 to 7 described above, a Cu—Ag alloy wire having a tensile strength of 1600 MPa or more can be obtained in step 8, which is a guideline for "high strength suitable for use as a wire for ultrafine probe pins with a diameter of 0.1 mm or less." After cold wire drawing, it is also preferable to perform shaving (peeling) in one or more of steps 5 to 7 in order to remove impurities present near the surface. Note that if shaving is performed after cold wire drawing, the cross-sectional area reduction rates before and after processing in steps 5 to 7 are values ​​that include the shaving (i.e., "the cross-sectional area reduction rates before and after the processing, calculated by considering cold wire drawing and shaving as a series of processing operations").

[0027] The methods and conditions for the cold wire drawing, shaving, and heat treatment in steps 5 to 7 may be conventionally known and are not particularly limited, but it is preferable that the heat treatment in step 5 be carried out at 300°C to 400°C for 0.5 to 3 hours, the heat treatment in step 6 be carried out at 250°C to 350°C for 0.5 to 3 hours, and the heat treatment in step 7 be carried out at 230°C to 330°C for 0.5 to 3 hours. The types of atmospheric gases for carrying out the heat treatments in steps 5 to 7 include a slightly reducing gas of 95% nitrogen and 5% hydrogen, and inert gases such as helium and argon.

[0028] Here, the heat treatments performed in steps 5 to 7 are stress relief annealing operations performed for stress relief, similar to steps 2 to 4 described above. Therefore, considering the composition of the metal raw material and the diameter of the metal rod after each cold wire drawing (or after cold wire drawing and shaving) (the length in both the vertical and horizontal directions when cold wire drawing into a rectangular shape is performed), a heat treatment temperature of less than 300°C in step 5 is not preferred because the stress relief effect is insufficient and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8. Similarly, a heat treatment temperature of less than 250°C in step 6 is not preferred because the stress relief effect is insufficient and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8. A heat treatment temperature of less than 230°C in step 7 is not preferred because the stress relief effect is insufficient and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8.

[0029] On the other hand, if the heat treatment temperature in step 5 exceeds 400°C, the size of the crystal grains of the Cu—Ag alloy will excessively increase, which is undesirable because the hardness of the Cu—Ag alloy wire obtained in step 8 will tend to decrease. Similarly, if the heat treatment temperature in step 6 exceeds 350°C, the size of the crystal grains of the Cu—Ag alloy will excessively increase, which is undesirable because the hardness of the Cu—Ag alloy wire obtained in step 8 will tend to decrease. If the heat treatment temperature in step 7 exceeds 330°C, the size of the crystal grains of the Cu—Ag alloy will excessively increase, which is undesirable because the hardness of the Cu—Ag alloy wire obtained in step 8 will tend to decrease.

[0030] Furthermore, if the heat treatment time in steps 5 to 7 is less than 0.5 hours, the stress relief effect is insufficient, and defects such as cracks tend to occur in the Cu—Ag alloy wire obtained in step 8, which is not preferable. On the other hand, if the heat treatment time in steps 5 to 7 exceeds 3 hours, the stress relief effect is not significantly improved, and productivity simply decreases, which is not preferable.

[0031] Step 8: Cold wire drawing is performed so that the cross-sectional area reduction rate relative to the metal rod in step 1 is 99.0% to 99.9999%, and a Cu—Ag alloy wire having a diameter of 0.1 mm or less containing 10.0 wt% to 30.0 wt% Ag, with the remainder consisting of Cu and inevitable impurities is obtained.

[0032] In this step 8, cold wire drawing is performed so that the area reduction ratio relative to the metal rod obtained in the above-mentioned step 1 (i.e., (cross-sectional area of ​​the metal rod in step 1 - cross-sectional area of ​​the Cu-Ag alloy wire in this step 8) ÷ cross-sectional area of ​​the metal rod in step 1 × 100) is 99.0% to 99.9999%. From an experimental point of view, when the area reduction ratio in this step 8 is within this numerical range, the Vickers hardness of the Cu-Ag alloy that has been subjected to cold wire drawing and heat treatment (or cold wire drawing, shaving and heat treatment) in the above-mentioned steps 2 to 7 tends to be improved by work hardening. Here, if the area reduction ratio relative to the metal rod obtained in the above-mentioned step 1 is less than 99.0%, the effect of improving the Vickers hardness of the Cu-Ag alloy tends not to be sufficiently obtained, which is not preferable. On the other hand, even if the cross-sectional area reduction rate with respect to the metal rod obtained in the above-mentioned step 1 exceeds 99.9999%, the toughness of the Cu—Ag alloy wire rod tends to decrease due to excessive work hardening, and the durability and reliability of the product tend to be impaired, which is not preferable.

[0033] The preferred diameter of the Cu—Ag alloy wire obtained in step 8 (the length and width in the case of a rectangular wire) is 0.1 mm or less. Here, if the diameter of the Cu—Ag alloy wire exceeds 0.1 mm, when it is processed into a probe pin, it tends to be unable to be applied to the continuity testing of semiconductor devices with multiple pins and narrow pitches, which is undesirable. On the other hand, although there is no particular limit on the lower limit of the diameter of the Cu—Ag alloy wire, it is preferable that the diameter of the Cu—Ag alloy wire be 0.01 mm or more. Even if the diameter of the Cu—Ag alloy wire is less than 0.01 mm, the market value of the wire as a probe pin for testing electrical and electronic components is not dramatically improved, and the wire tends to simply increase manufacturing costs.

[0034] B. Cu—Ag Alloy Wire The Cu—Ag alloy wire according to the present application is manufactured by the above-described manufacturing method of the Cu—Ag alloy wire according to the present application. The Cu—Ag alloy wire according to the present application is characterized by having an extremely excellent tensile strength of 1600 MPa or more, due to the above-described requirements, particularly the above-described manufacturing method of the Cu—Ag alloy wire according to the present application, in which "after repeating cold wire drawing and heat treatment multiple times while gradually increasing the cross-sectional area reduction rate before and after processing in steps 2 to 4, cold wire drawing and heat treatment (or cold wire drawing, shaving, and heat treatment) are further repeated multiple times so that the cross-sectional area reduction rate before and after processing is 80% to 95%, which is greater than that of steps 2 to 4." This characteristic allows the Cu—Ag alloy wire according to the present application to be suitably used as an ultrafine probe pin with a diameter of 0.1 mm or less.

[0035] Here, if the tensile strength of the Cu—Ag alloy wire is less than 1600 MPa, when used as an ultrafine probe pin with a diameter of 0.1 mm or less, the strength is insufficient, causing problems such as breaking or bending, and the durability and reliability of the product tend to be insufficient, which is undesirable. On the other hand, although there is no particular upper limit on the tensile strength of the Cu—Ag alloy wire, the tensile strength of the Cu—Ag alloy wire is preferably 1900 MPa or less. This is because even if the tensile strength of the Cu—Ag alloy wire exceeds 1900 MPa, the function as a probe pin is not significantly improved, and rather, flexibility tends to decrease, resulting in a tendency for durability against repeated bending to deteriorate.

[0036] Furthermore, the Cu—Ag alloy wire according to the present application preferably has a conductivity of 46.0 IACS% or more, a resistivity of 4.0 μΩ·cm or less, and a Vickers hardness of 360 HV or more. Here, if the conductivity of the Cu—Ag alloy wire is less than 46.0 IACS%, when used as a probe pin, it tends to be difficult to accurately detect minute currents in an electrical circuit formed on a substrate material such as a semiconductor device, which is undesirable. On the other hand, while there is no particular upper limit on the conductivity of the Cu—Ag alloy wire, it is preferable that the conductivity of the Cu—Ag alloy wire be 80.0 IACS% or less. This is because if the conductivity of the Cu—Ag alloy wire exceeds 80.0 IACS%, it tends to be difficult to achieve both high conductivity and high hardness.

[0037] Furthermore, if the resistivity of the Cu—Ag alloy wire exceeds 4.0 μΩ·cm, the electrical resistance of the Cu—Ag alloy wire will be too high, and when used as a probe pin, it will tend to be unable to accurately detect minute currents in an electrical circuit formed on a substrate material such as a semiconductor device, which is undesirable. On the other hand, although there is no particular limit on the lower limit of the resistivity of the Cu—Ag alloy wire, it is preferable that the resistivity of the Cu—Ag alloy wire be 2.0 μΩ·cm or more. This is because if the resistivity of the Cu—Ag alloy wire is less than 2.0 μΩ·cm, it tends to be difficult to achieve both low resistivity and high hardness. Furthermore, if the Vickers hardness of the Cu—Ag alloy wire is less than 360 HV, it is undesirable because when used as a probe pin to repeatedly perform continuity tests on electrical and electronic components, defects such as bending or bending will occur, and the durability and reliability of the product will tend to be insufficient. On the other hand, although there is no particular upper limit to the Vickers hardness of the Cu—Ag alloy wire, the Vickers hardness of the Cu—Ag alloy wire is preferably 450 HV or less. This is because even if the Vickers hardness of the Cu—Ag alloy wire exceeds 450 HV, the function as a probe pin is not significantly improved, and rather, the processability is reduced, making it more time-consuming to process the wire into a desired probe pin shape, which tends to reduce productivity.

[0038] C. Probe Pin for Inspecting Electrical and Electronic Components The probe pin for inspecting electrical and electronic components according to the present application is characterized by being obtained using the Cu-Ag alloy wire according to the present application. By satisfying the requirements, the probe pin for inspecting electrical and electronic components according to the present application can be suitably used as a probe pin for inspecting electrical and electronic components used in inspecting semiconductor integrated circuits and semiconductor devices equipped with narrow-pitch electrodes, and therefore has high market value and is excellent in durability and reliability.

[0039] The invention of the present application will be explained in more detail below by way of examples, but the invention of the present application is not limited to these examples.

[0040] Continuous casting was performed using a metal raw material formulated to have a composition of 18.8 wt% Ag, excluding inevitable impurities, and the remainder Cu, to obtain a metal rod with a diameter of 15 mm. This metal rod was subjected to cold wire drawing using a groove rolling mill so that the cross-sectional area reduction rate before and after processing was 18.47%, and then heat treated at 450 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water-quenched. Next, cold wire drawing was performed so that the cross-sectional area reduction rate before and after processing was 30.56%, and then heat treated at 450 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water-quenched. Subsequently, cold wire drawing was performed so that the cross-sectional area reduction rate before and after processing was 36.00%, and then heat treated at 400 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water-quenched. Furthermore, after cold wire drawing and shaving to a thickness of 25 μm were performed so that the cross-sectional area reduction rate before and after processing was 85.94% (more specifically, after cold wire drawing and subsequent shaving to a thickness of 25 μm), heat treatment was performed at 350 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water quenching was performed. In addition, after cold wire drawing was performed so that the cross-sectional area reduction rate before and after processing was 91.28%, heat treatment was performed at 300 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water quenching was performed. Then, after cold wire drawing was performed so that the cross-sectional area reduction rate before and after processing was 84.00%, heat treatment was performed at 275 ° C. for 1 hour in a slightly reducing gas atmosphere of 95% nitrogen and 5% hydrogen, and water quenching was performed. Finally, the metal rod (the metal rod having a diameter of 15 mm) was subjected to cold wire drawing so that the cross-sectional area reduction rate was 99.9998%, thereby obtaining a Cu—Ag alloy wire having a diameter of 0.02 mm and containing 18.8 wt % Ag and the remainder being Cu and inevitable impurities.

[0041] A part of the Cu—Ag alloy wire obtained by the method of this example was cut to a length of 500 mm to prepare a test piece, and the tensile strength was measured using a tensile strength tester. Next, a part of the Cu—Ag alloy wire obtained by the method of this example was separately cut to a length of 1000 mm to prepare a sample piece, and the resistivity was measured using a resistance meter. Subsequently, the electrical conductivity (IACS%) was calculated from the resistivity value obtained by this measurement (more specifically, when the resistivity, i.e., the resistivity, was 1.7241×10 －８The conductivity of the test piece was calculated from the measured resistivity, with the conductivity of international standard annealed copper in Ω·m taken as 100%. Furthermore, a portion of the Cu—Ag alloy wire obtained by the method of this example was separately cut to a length of 10 mm, and the cross section was polished to make a smooth specimen. The Vickers hardness was measured using a micro Vickers hardness tester at a test load of HV 0.005. The results of these measurements are shown in Table 1. Table 1 also shows the manufacturing conditions of this example, namely, "the cross-sectional reduction rate (%) of the Cu—Ag alloy before and after each processing, i.e., (cross-sectional area of ​​the Cu—Ag alloy before processing - cross-sectional area of ​​the Cu—Ag alloy after processing) ÷ cross-sectional area of ​​the Cu—Ag alloy before processing × 100)" and "the cross-sectional reduction rate (%) of the Cu—Ag alloy relative to the metal rod after continuous casting, i.e., (cross-sectional area of ​​the metal rod after continuous casting - cross-sectional area of ​​the Cu—Ag alloy after each processing) ÷ cross-sectional area of ​​the metal rod after continuous casting × 100)."

[0042]

[0043] As can be seen from the above examples, "a metal rod is obtained by melting a metal raw material formulated to have a composition of 10.0 wt% to 30.0 wt% Ag, excluding unavoidable impurities, with the remainder being Cu, and then cold wiredrawing and heat treatment are repeated multiple times while gradually increasing the cross-sectional area reduction rate before and after processing, and cold wiredrawing and heat treatment, and cold wiredrawing, shaving and heat treatment are further performed multiple times so that the cross-sectional area reduction rate before and after processing is larger than that of the cold wiredrawing, and finally cold wiredrawing is performed so that the cross-sectional area reduction rate relative to the metal rod is 99.0% to 99.9999%." This makes it possible to obtain a Cu-Ag alloy wire rod having a diameter of 0.1 mm or less and a tensile strength of 1600 MPa or more, which contains 10.0 wt% to 30.0 wt% Ag, with the remainder being Cu and unavoidable impurities. The probe pin for inspecting electrical and electronic components obtained using the Cu-Ag alloy wire obtained in this example has the excellent properties shown in Table 1, and therefore it can be determined that it is suitable as a probe pin for use in inspecting semiconductor integrated circuits and semiconductor devices equipped with narrow-pitch electrodes.

[0044] The method for producing a Cu—Ag alloy wire according to the present application and the Cu—Ag alloy wire produced by this method can be used for probe pins for inspecting electrical and electronic components and for the manufacture of such probe pins. In particular, the method for producing a Cu—Ag alloy wire according to the present application and the Cu—Ag alloy wire produced by this method can be suitably used for probe pins used in inspecting electrical and electronic components such as semiconductor integrated circuits and semiconductor devices that have narrow-pitch electrodes and for the manufacture of such probe pins.

Claims

1. A method for manufacturing a Cu-Ag alloy wire rod, comprising the following steps 1 to 8 in order. Step 1: A metal rod is obtained by melting a metal raw material that is mixed so that the composition is 10.0 wt% to 30.0 wt% Ag, excluding inevitable impurities, and the remainder is Cu. Step 2: After cold wire drawing, the wire is heat-treated in a slightly reducing gas or inert gas atmosphere. Step 3: After cold wire drawing, the wire is heat-treated in a slightly reducing gas or inert gas atmosphere so that the reduction in area between before and after processing is 25% to 35%. Step 4: After cold wire drawing, the wire is heat-treated in a slightly reducing gas or inert gas atmosphere so that the reduction in area between before and after processing is 30% to 40%. Step 5: After cold wire drawing or cold wire drawing and shaving, the wire is heat-treated in a slightly reducing gas or inert gas atmosphere so that the reduction in area between before and after processing is 80% to 90%. Step 6: After performing cold wire drawing or cold wire drawing and shaving so that the cross-sectional area reduction rate before and after processing is 85% to 95%, heat treatment is performed in a slightly reducing gas or inert gas atmosphere. Step 7: After performing cold wire drawing or cold wire drawing and shaving so that the cross-sectional area reduction rate before and after processing is 80% to 90%, heat treatment is performed in a slightly reducing gas or inert gas atmosphere. Step 8: After performing cold wire drawing so that the cross-sectional area reduction rate for the metal rod is 99.0% to 99.9999%, a Cu-Ag alloy wire having a diameter of 0.1 mm or less is obtained, which contains 10.0 wt% to 30.0 wt% Ag and the balance consisting of Cu and unavoidable impurities.

2. The method for producing a Cu-Ag alloy wire according to claim 1, wherein the heat treatments in steps 2 and 3 are performed at 400°C to 500°C for 0.5 to 3 hours, the heat treatment in step 4 is performed at 350°C to 450°C for 0.5 to 3 hours, the heat treatment in step 5 is performed at 300°C to 400°C for 0.5 to 3 hours, the heat treatment in step 6 is performed at 250°C to 350°C for 0.5 to 3 hours, and the heat treatment in step 7 is performed at 230°C to 330°C for 0.5 to 3 hours.

3. A Cu-Ag alloy wire produced by the method for producing a Cu-Ag alloy wire according to claim 1 or 2, characterized in that the Cu-Ag alloy wire has a tensile strength of 1600 MPa or more.

4. A Cu-Ag alloy wire according to claim 3, having an electrical conductivity of 46.0 IACS% or more, a resistivity of 4.0 μΩ·cm or less, and a Vickers hardness of 360 HV or more.

5. A probe pin for inspecting electric / electronic parts, obtained by using the Cu-Ag alloy wire rod according to claim 3.

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