Manufacturing method for copper-silver alloy sheet material and manufacturing method for electrode sheet of probe card

Abstract

To obtain a sheet made of a copper-silver alloy which excels in hardness, and a sheet for an electrode of a probe card using the sheet.SOLUTION: This method comprises at least: (a) obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) obtaining a sheet material having a thickness of 0.01 to 0.10 mm by performing rolling processing on the base material at least once; and (c) performing annealing treatment on the sheet material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a copper-silver alloy sheet material and a method for manufacturing an electrode sheet for a probe card, and more particularly to a method for manufacturing a copper-silver alloy sheet material having excellent hardness and a method for manufacturing an electrode sheet for a probe card. [Background technology]

[0002] As one method for manufacturing various parts and members using a copper-silver alloy, Patent Document 1 below discloses a method for manufacturing an ultrafine copper alloy wire that has strength, high conductivity, and excellent heat resistance and is resistant to deterioration in strength even under thermal load. Furthermore, Patent Document 2 below discloses a method for producing a copper alloy that can achieve high strength and high electrical conductivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4143086 [Patent Document 2] Japanese Patent Application Publication No. 2022-28598 Summary of the Invention [Problem to be solved by the invention]

[0004] The applicant took notice of the high conductivity properties of copper-silver alloys and came up with the idea of ​​producing an electrode sheet to be used in semiconductor inspection probe cards. However, electrode sheets used in semiconductor inspection probe cards are required to have high hardness, and a copper-silver alloy sheet material having a satisfactory hardness has not yet been found.

[0005] Therefore, the present invention provides Conductivity and The object of the present invention is to obtain a copper-silver alloy sheet having excellent hardness and an electrode sheet for a probe card. [Means for solving the problem]

[0006] A preferred embodiment of the present invention, which has been made to solve the above problems, is a method for manufacturing a copper-silver alloy sheet material, comprising: The copper-silver alloy is composed of 70 to 92 mass% copper, 8 to 30 mass% silver, and 0 to 1 mass% of the remainder (including unavoidable impurities), (a) The aforementioned By continuous casting of copper-silver alloy , basis (b) performing at least one rolling treatment on the substrate to obtain a material; , Shi (c) a step of annealing the sheet material, and (c) a step of annealing the sheet material, Conductivity is 38% IACS or more, and It is characterized by having a Vickers hardness of 280 HV or more.

[0007] Another aspect of the present invention is a method for manufacturing an electrode sheet for a probe card, comprising: The copper-silver alloy is composed of 70 to 92 mass% copper, 8 to 30 mass% silver, and 0 to 1 mass% of the remainder (including unavoidable impurities), (a) The aforementioned By continuous casting of copper-silver alloy , basis (b) performing at least one rolling treatment on the substrate to obtain a material; , Shi (c) a step of annealing the sheet material, and (d) a step of annealing the sheet material, wherein the electrode sheet made of the sheet material that has been subjected to (c) is Conductivity is 38% IACS or more, and It is characterized by a Vickers hardness of 280 HV or more. [Effects of the Invention]

[0008] According to the present invention, Conductivity and A copper-silver alloy sheet and an electrode sheet for a probe card having excellent hardness can be obtained. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a flowchart showing steps in a method for manufacturing a copper-silver alloy sheet material according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification, the use of "to" to indicate a range of values ​​means that the upper and lower limits are included in the range. [Example]

[0011] <1> Overall configuration (Fig. 1) The method for producing a copper-silver alloy sheet material according to the present invention mainly includes at least a substrate forming step, a sheet material forming step, and an annealing step. Each step will be described in detail below.

[0012] <2> Step (a): Base material formation step (S100) The substrate forming step is a step for forming a substrate of a predetermined shape made of a copper-silver alloy.

[0013] <2.1> Composition of copper-silver alloy In the present invention, the composition of the copper-silver alloy to be melted is not particularly limited, and can be appropriately designed depending on the properties required for the intended use of the completed sheet material. For example, when the sheet material obtained by the manufacturing method according to the present invention is used as an electrode sheet for a probe card, the following composition can be adopted from the viewpoint of obtaining high hardness. Copper (Cu): 70 to 92 mass%, preferably 70 to 85 mass% Silver (Ag): 8 to 30% by mass, preferably 15 to 30% by mass Balance (including unavoidable impurities): 0 to 1% by mass

[0014] <2.2> Method for forming substrate In the present invention, it is preferable to use a continuous casting method for forming the substrate. Continuous casting is a method of extracting a long, continuous casting by gradually withdrawing molten metal from a mold as it cools and solidifies. By using the continuous casting method, the alloy constituent elements are more likely to be uniformly dispersed, so that the solution treatment consisting of high-temperature heat treatment and rapid cooling can be omitted. Furthermore, the continuous casting method makes it easy to control the structure of the base material during continuous casting (e.g., controlling the crystal grain size in anticipation of the characteristics of the final shape of the sheet material, controlling the precipitate layer to be left at the grain boundaries, etc.). Therefore, by properly managing this structure control, it is possible to maintain the previously thinned crystal grain size until the final shape of the sheet material, and to expect to improve the hardness and strength of the sheet material. Furthermore, if the crystal grain size of the sheet material can be reduced by appropriately controlling the above-mentioned structure, the generation of burrs can be suppressed when the sheet material is cut, and an improvement in yield can also be expected.

[0015] <2.3> Cross-sectional shape of the substrate In the present invention, the cross-sectional shape of the substrate is not particularly limited, and a circular shape, rectangular shape, or the like can be appropriately selected depending on the intended use of the completed sheet material.

[0016] For example, if the sheet material is used for a busbar with a low aspect ratio (ratio of thickness to width) and a thickness of 0.5 mm or more, it is preferable that the cross section of the substrate be circular, as this is beneficial in terms of processing rectangular conductors for carrying large currents.

[0017] Furthermore, when the sheet material is used for producing rectangular wire, it is preferable that the cross-sectional shape of the substrate be rectangular rather than circular. This is because a substrate with a circular cross-sectional shape tends to have stress concentration in the center, making it more susceptible to edge cracking and meandering during rolling to form a thin sheet material, which may result in a poor yield even if the edge portions are removed. Furthermore, the cross-sectional shape of the sheet material after rolling may become racetrack-shaped (with curved sides), which may result in a poor space factor when used as is for winding. Therefore, the sheet material according to the present invention is particularly advantageous for producing rectangular wire with a high aspect ratio.

[0018] <2.4> Casting thickness of base material In the present invention, the casting thickness of the substrate is not particularly limited, and can be appropriately designed depending on the properties required of the completed sheet material. For example, if the sheet material is to be used for electrodes in a probe card and the thickness of the sheet material obtained in the sheet material forming process described below is expected to be 0.025 to 0.050 mm, it is preferable to set the thickness of the substrate to 15 to 20 mm. For example, if the casting thickness of the base material is thinner than 15 mm, it is possible that the required degree of processing (rolling reduction) cannot be achieved, resulting in the problem of not being able to obtain the required hardness. On the other hand, if the casting thickness of the base material is thicker than 20 mm, the processing limit will be reached at a relatively high thickness, resulting in severe cracking, especially at the edges. This will lead to an increase in the number of heat treatment steps, which will increase manufacturing costs. Furthermore, it is possible that problems will arise, such as the increased difficulty of optimizing the heat treatment conditions and the difficulty of achieving reproducibility, and this is why these problems are being avoided.

[0019] <2.5> Casting speed of base material In the present invention, the casting speed of the substrate is not particularly limited, and can be appropriately designed depending on the properties required of the completed sheet material. For example, when the sheet material is to be used as an electrode for a probe card, assuming that the thickness of the sheet material obtained in the sheet material forming process described below is 15 to 20 mm, the casting speed is preferably set to 50 to 1000 mm / min, and more preferably 100 to 300 mm / min.

[0020] <3> Step (b): Sheet material forming step (S200) The sheet material forming step is a step for processing a base material to a predetermined thickness and forming it into a sheet-like member (sheet material). This step includes at least a rolling treatment. In the present invention, the number of times the rolling process is performed in this step is not particularly limited, and may be appropriately designed taking into account the thickness and characteristics of the substrate that is the starting point of this step and the thickness and characteristics of the sheet material that is the destination of this step.

[0021] <3.1> Rolling process The rolling process is a process in which a continuous force is applied to a substrate to thin it. In the rolling process, a pair of rolls placed in parallel are rotated, and the material to be rolled is passed between the pair of rolls. In the present invention, the type of rolling treatment is not particularly limited, but for example, cold rolling or the like can be used. In the present invention, the thickness of the substrate (intermediate product or final product as a sheet material) after rolling treatment may be appropriately designed.

[0022] <3.2> Heat treatment In addition, in this step, when the rolled substrate is to be rolled again, it is preferable to perform an appropriate heat treatment beforehand. In the present invention, the conditions (heating temperature, heating time, etc.) for the heat treatment before re-rolling are not particularly limited.

[0023] <4> Process (c): Annealing process (S300) The annealing process is a heating process for removing residual stress from a sheet material that has been rolled to a predetermined thickness, and is a process known as annealing.

[0024] <4.1>Heating temperature The heating temperature in this step is preferably in the range of 200 to 500° C. in order to prevent recovery or abnormal crystal grain growth.

[0025] <4.2> Heating time The heating time in this step is not particularly limited because the optimum time varies depending on the heating temperature. However, when the heating temperature is in the range of 200 to 500°C, it is preferably in the range of approximately 60 to 4500 minutes.

[0026] <4.2> Sheet material thickness In the present invention, the thickness of the sheet material after this step is not particularly limited, but when the sheet material is used for electrodes of a probe card, it is preferably set to 0.025 to 0.050 mm.

[0027] <5> Other processes The sheet material that has been subjected to step (c) can be processed into a desired shape depending on the final application. For example, by cutting the sheet material to a predetermined width (0.5 to 2 mm), an ultra-fine rectangular conductor wire can be produced. Furthermore, by processing the sheet material into any desired shape, it can also be used as an electrode sheet for bus bars, ribbon heaters, and probe cards used in semiconductor testing.

[0028] <6> Experimental example A plurality of test specimens were prepared using the manufacturing method according to the present invention, and the hardness (Vickers hardness) of each electrical characteristic test lead wire was measured using a Vickers hardness tester in accordance with JIS Z 2244. The evaluation criteria are as follows:

[0029] [Evaluation criteria] 〇:280HV or more ×: Less than 280HV

[0030] Additionally, the electrical resistance of each specimen was measured using the double bridge method in a room controlled at 20°C (±2°C), and the average conductivity (%IACS) was calculated. The distance between the voltage terminals was 500 mm. The calculation results are shown in Table 2. The conductivity required for an electrode sheet of a probe card is 38% IACS or more.

[0031] <6.1> Manufacturing conditions The manufacturing conditions for each test specimen were set as shown in Table 1 below. The details of each step are as follows:

[0032] [Table 1] JPEG0007789257000001.jpg58151

[0033] (a) Substrate formation step: Raw materials were heated to 1000 to 1400° C. and melted to prepare a composition (molten metal) having the composition ratio shown in Table 1. The casting speed was set to 300 mm / min, the melt (molten metal) was poured into a mold, and cooled to room temperature within 10 minutes to cast a substrate A having a thickness or diameter of 6 to 14.3 mm.

[0034] (b) Sheet material forming step: The substrate A was cold rolled from a thickness or diameter of 6 to 14.3 mm to a thickness of 1.83 to 4.56 mm, to produce a rolled substrate B. The rolled substrate B was then heated in an N2 gas atmosphere at 370 to 450°C for 2400 minutes. The rolled substrate B was then further cold-rolled from a thickness of 1.83 to 4.56 mm to a thickness of 0.05 to 0.6 mm to produce a sheet material C with a desired thickness.

[0035] (c) Annealing step: Sheet material C was annealed in an N2 gas atmosphere at 200°C for 60 minutes to obtain specimens 1 to 10.

[0036] <6.2>Measurement results The measurement results for each test specimen are shown in Table 2.

[0037] [Table 2] JPEG0007789257000002.jpg13150

[0038] <6.3> Verification results As shown in Table 2, the sheet materials for specimens 3 to 4 and specimens 6 to 10 were able to achieve the Vickers hardness (280 HV or more) and conductivity (38% IACS or more) required for electrode sheets for probe cards. [Explanation of symbols]

[0039] S100: Base material formation process S200: Sheet material forming process S300: Annealing process A: Base material B: Base material after rolling C: Sheet material

Claims

1. A method for manufacturing a copper-silver alloy sheet material, comprising: The copper-silver alloy is composed of 70 to 92 mass% copper, 8 to 30 mass% silver, and 0 to 1 mass% of the balance (including unavoidable impurities), (a) obtaining a substrate by continuous casting of the copper-silver alloy; (b) performing at least one rolling treatment on the substrate to obtain a sheet material; (c) subjecting the sheet material to an annealing treatment; At least The sheet material that has undergone (c) has a conductivity of 38% IACS or more and a Vickers hardness of 280 HV or more. A method for manufacturing copper-silver alloy sheet material.

2. A method for manufacturing an electrode sheet for a probe card, comprising: The copper-silver alloy is composed of 70 to 92 mass% copper, 8 to 30 mass% silver, and 0 to 1 mass% of the balance (including unavoidable impurities), (a) obtaining a substrate by continuous casting of the copper-silver alloy; (b) performing at least one rolling treatment on the substrate to obtain a sheet material; (c) subjecting the sheet material to an annealing treatment; At least The electrode sheet made of the sheet material that has undergone (c) has a conductivity of 38% IACS or more and a Vickers hardness of 280 HV or more. A method for manufacturing an electrode sheet for a probe card.

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