Method for manufacturing sheet material made of copper silver alloy, and method for manufacturing electrode sheet of probe card

Abstract

[PROBLEM] To provide a sheet made of a copper silver alloy of excellent hardness, and an electrode sheet of a probe card using the sheet. [SOLUTION] The present invention includes at least: (a) a step for obtaining a base material having a thickness or a diameter of 6-30 mm by continuously casting a copper silver alloy; (b) a step for obtaining a sheet material having a thickness of 0.01-0.10 mm by performing at least one rolling treatment on the base material; and (c) a step for subjecting the sheet material to an annealing treatment.

Description

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

[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.

[0002] As one method for manufacturing various parts and components 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. Patent Document 2 below also discloses a method for manufacturing a copper alloy that can achieve high strength and high conductivity.

[0003] Japanese Patent No. 4143086 JP 2022-28598 A

[0004] The applicant focused on the highly conductive properties of copper-silver alloys and came up with the idea of ​​producing electrode sheets for use in semiconductor inspection probe cards. However, electrode sheets for use in semiconductor inspection probe cards are required to have high hardness, and a copper-silver alloy sheet material with a satisfactory hardness has not yet been found.

[0005] Therefore, an object of the present invention is to provide a copper-silver alloy sheet having excellent hardness and an electrode sheet for a probe card.

[0006] A preferred embodiment of the present invention, which has been made to solve the above-mentioned problems, is a method for manufacturing a copper-silver alloy sheet material, which includes at least the steps of: (a) obtaining a substrate having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing at least one rolling process on the substrate to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) annealing the sheet material, wherein the sheet material that has undergone step (c) has 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, which includes at least the steps of: (a) obtaining a substrate having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing at least one rolling process on the substrate to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) subjecting the sheet material to an annealing process, wherein the electrode sheet made of the sheet material that has undergone step (c) has a Vickers hardness of 280 HV or more.

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

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

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

[0011] <1> Overall Configuration (FIG. 1) The method for manufacturing 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): Substrate Forming 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 according to the properties required for the intended use of the finished sheet material. For example, when the sheet material obtained by the manufacturing method of 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 mass %, preferably 15 to 30 mass % Balance (including unavoidable impurities): 0 to 1 mass %

[0014] <2.2> Method for Forming Substrate In the present invention, continuous casting is preferably used to form the substrate. Continuous casting is a method of extracting a long, continuous casting by gradually withdrawing a molten metal from a mold while it cools and solidifies. Continuous casting facilitates uniform dispersion of alloy constituent elements, eliminating the need for solution treatment, which involves high-temperature heat treatment and rapid cooling. Furthermore, continuous casting allows for easy control of the substrate's structure 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 precipitation layer to be left at the grain boundaries, etc.). By properly managing this structure control, the previously reduced crystal grain size can be maintained until the final shape of the sheet material, potentially improving the hardness and strength of the sheet material. Furthermore, by properly managing the above-mentioned structure morphology, the crystal grain size of the sheet material can be reduced, thereby suppressing burrs when cutting the sheet material and potentially improving yield.

[0015] <2.3> Cross-sectional shape of 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, when the sheet material is used for a bus bar having 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 is circular, as this is advantageous in terms of processing a rectangular conductor for carrying a large current.

[0017] Furthermore, when the sheet material is used for flat wire applications, 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, and removing these edge portions may not improve yield. Also, the cross-sectional shape of the sheet material after rolling may become racetrack-shaped (with curved sides), which may not increase the space factor when used as is for winding. Therefore, the sheet material of the present invention is particularly advantageous for producing flat wire with a high aspect ratio.

[0018] <2.4> Casting Thickness of Substrate In the present invention, the casting thickness of the substrate is not particularly limited and can be appropriately designed depending on the characteristics required of the finished sheet material. For example, if the sheet material is 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. This is because, for example, if the casting thickness of the substrate is thinner than 15 mm, it is possible that the degree of processing (rolling reduction) cannot be achieved and the necessary hardness cannot be obtained. If the casting thickness of the substrate is thicker than 20 mm, the processing limit will be reached at a relatively thick stage, causing severe cracking, especially at the edges. This leads to an increase in heat treatment steps and increased manufacturing costs. Furthermore, it is possible that problems such as increased difficulty in optimizing heat treatment conditions and difficulty in achieving reproducibility may arise, and these problems are avoided.

[0019] <2.5> Casting Speed ​​of Substrate 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 used for electrodes in a probe card, and the thickness of the sheet material obtained in the sheet material forming step described below is assumed to be 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 substrate to a predetermined thickness to form a sheet-like member (sheet material). This step includes at least a rolling process. 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 in consideration of the thickness and characteristics of the substrate, which is the starting point of this step, and the thickness and characteristics of the sheet material, which is the end point of this step.

[0021] <3.1> Rolling Treatment Rolling treatment is a process in which a continuous force is applied to a target substrate to thin the substrate. In rolling treatment, a pair of rolls placed in parallel is 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 cold rolling, for example, can be used. In addition, in the present invention, the thickness of the substrate (intermediate product or final product as a sheet material) after rolling treatment can be designed appropriately.

[0022] <3.2> Heat Treatment In addition, in this step, when the base material after the rolling treatment 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 the re-rolling are not particularly limited.

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

[0024] <4.1> Heating Temperature The heating temperature in this step is preferably in the range of 200 to 500° C. from the viewpoint of preventing recovery or avoiding abnormal 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 4,500 minutes.

[0026] <4.2> Thickness of Sheet Material 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 preferable to set the thickness to 0.025 to 0.050 mm.

[0027] <5> Other Steps The sheet material that has undergone step (c) can be processed into a desired shape depending on the final application. For example, by cutting the sheet material to a desired 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 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] ◯: 280HV or more ×: Less than 280HV

[0030] Additionally, the electrical resistance of each test 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 higher.

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

[0032] [Table 1]

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

[0034] (b) Sheet material forming process: 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 rolled substrate B. Then, rolled substrate B was heated at 370 to 450°C for 2,400 minutes in an N2 gas atmosphere. Then, rolled substrate B was 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 sheet material C with the desired thickness.

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

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

[0037] [Table 2]

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

[0039] S100: Substrate forming step S200: Sheet material forming step S300: Annealing step A: Substrate B: Rolled substrate C: Sheet material

Claims

1. A method for producing a copper-silver alloy sheet material, comprising at least the steps of: (a) obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing a rolling process on the base material at least once to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) performing an annealing process on the sheet material, wherein the sheet material that has been subjected to (c) has a Vickers hardness of 280 HV or more.

2. A method for producing a copper-silver alloy sheet material, comprising at least the steps of: (a) obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing at least one rolling process on the base material to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) performing an annealing process on the sheet material, wherein the silver content in the copper-silver alloy is 8 to 30 mass %, the casting speed in (a) is 50 to 1000 mm / min, the heating temperature and heating time of the heat treatment in (c) are 200 to 500°C and 60 to 4500 minutes, and the sheet material that has been subjected to (c) has a Vickers hardness of 280 HV or more.

3. The method for manufacturing a copper-silver alloy sheet material according to claim 1 or 2, characterized in that in (a), the cross-sectional shape of the substrate is rectangular.

4. A method for manufacturing an electrode sheet for a probe card, comprising at least the steps of: (a) obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing a rolling process on the base material at least once to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) subjecting the sheet material to an annealing process, wherein the electrode sheet made of the sheet material that has been subjected to (c) has a Vickers hardness of 280 HV or more.

5. A method for manufacturing an electrode sheet for a probe card, comprising at least the steps of: (a) obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) performing at least one rolling process on the base material to obtain a sheet material having a thickness of 0.01 to 0.10 mm; and (c) performing an annealing process on the sheet material, wherein the silver content in the copper-silver alloy is 8 to 30 mass %, the casting speed in (a) is 50 to 1000 mm / min, the heating temperature and heating time in the heat treatment in (c) are 200 to 500°C and 60 to 4500 minutes, and the electrode sheet made of the sheet material after (c) has a Vickers hardness of 280 HV or more.

6. A method for manufacturing an electrode sheet for a probe card according to claim 4 or 5, characterized in that in (a), the cross-sectional shape of the substrate is rectangular.

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