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

Abstract

The present invention provides a sheet made of copper-silver alloy having excellent hardness and a sheet for an electrode of a probe card using the same. A method for manufacturing a sheet made of copper-silver alloy comprises at least: (a) a step of obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of copper-silver alloy, (b) a step of subjecting the base material to at least one or more times of calendering to obtain a sheet having a thickness of 0.01 to 0.10 mm, and (c) a step of subjecting the sheet to annealing.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a sheet of copper-silver alloy and a method for manufacturing an electrode sheet for a probe card, and more specifically, to a method for manufacturing a sheet of copper-silver alloy with excellent hardness and a method for manufacturing an electrode sheet for a probe card. Background Technology

[0002] As one of the methods for manufacturing various parts and components using copper-silver alloys, the following Patent Document 1 discloses a method for manufacturing ultra-fine copper alloy wires that have strength, high conductivity, are difficult to reduce in strength even under heat load, and have excellent heat resistance.

[0003] Furthermore, Patent Document 2 discloses a method for manufacturing copper alloys with high strength and high conductivity.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 43143086

[0007] Patent Document 2: Japanese Patent Application Publication No. 2022-28598 Summary of the Invention

[0008] The problem to be solved by the present invention

[0009] The applicant focused on the properties of copper-silver alloys with high conductivity and conceived the idea of ​​manufacturing electrode sheets for use in semiconductor testing probe cards.

[0010] However, the electrode sheets used in semiconductor inspection probe cards require high hardness, and sheets made of copper-silver alloys that meet the required hardness have not yet been developed.

[0011] Therefore, the purpose of this invention is to obtain a copper-silver alloy sheet with excellent hardness and an electrode sheet for a probe card.

[0012] Problem-solving methods

[0013] A preferred embodiment of the present invention, made to solve the above-mentioned problems, is a method for manufacturing a sheet of copper-silver alloy, characterized in that the method comprises at least: (a) a step of obtaining a substrate with a thickness or diameter of 6 to 30 mm by continuous casting of copper-silver alloy; (b) a step of performing at least one rolling process on the substrate to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing an annealing process on the sheet, wherein the Vickers hardness of the sheet after step (c) is 280 HV or higher.

[0014] Another aspect of the present invention is a method for manufacturing an electrode sheet for a probe card, characterized in that the method includes at least: (a) a step of obtaining a substrate with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) a step of performing a rolling process on the substrate at least once to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing an annealing process on the sheet, wherein the electrode sheet formed from the sheet obtained by step (c) has a Vickers hardness of 280 HV or higher.

[0015] Effects of the present invention

[0016] According to the present invention, it is possible to obtain copper-silver alloy sheets and electrode sheets for probe cards with excellent hardness. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the process of manufacturing the copper-silver alloy sheet involved in this invention. Detailed Implementation

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0019] In this specification, the upper and lower limits of the values ​​indicated by the "~" sign are included within that range.

[0020] Example

[0021] <1> Overall composition ( Figure 1 )

[0022] The manufacturing method of the copper-silver alloy sheet involved in this invention mainly includes at least a substrate forming process, a sheet forming process, and an annealing process.

[0023] The following is a detailed explanation of each process.

[0024] <2> Process (a): Substrate formation process (S100)

[0025] The substrate forming process is a process used to form a substrate of a predetermined shape made of a copper-silver alloy.

[0026] <2.1> Composition of copper-silver alloy

[0027] In this invention, the composition of the molten copper-silver alloy is not particularly limited and can be appropriately designed according to the characteristics required for the intended use of the finished sheet.

[0028] For example, when using the sheet obtained by the manufacturing method according to the present invention as an electrode sheet for a probe card, from the viewpoint of obtaining high hardness, the following composition can be adopted.

[0029] Copper (Cu): 70–92% by mass, preferably 70–85% by mass

[0030] Silver (Ag): 8–30% by mass, preferably 15–30% by mass

[0031] • Balance (including unavoidable impurities): 0–1% by mass

[0032] <2.2> Method for forming the substrate

[0033] In this invention, the substrate is preferably formed using a continuous casting method.

[0034] Continuous casting refers to a method in which molten metal is slowly drawn and solidified while being cooled in a mold, thereby removing long, connected castings.

[0035] According to the continuous casting method, since the alloying elements are easily and uniformly dispersed, the solution treatment consisting of high-temperature heat treatment and rapid cooling process can be omitted.

[0036] Furthermore, according to the continuous casting method, the microstructure of the substrate can be easily controlled during continuous casting (e.g., the grain diameter that determines the final shape of the sheet, the control of the precipitate layer remaining at the grain boundaries, etc.). Therefore, by properly managing this microstructure control, it is expected that the pre-refined grain diameter can be maintained to the final shape of the sheet, and the hardness and strength of the sheet can be improved.

[0037] Furthermore, if the crystal grain size of the sheet can be reduced through proper management of the above-mentioned organizational morphology, the generation of burrs can be suppressed when cutting the sheet, and the yield rate can also be improved.

[0038] <2.3> Cross-sectional shape of the substrate

[0039] In this invention, the cross-sectional shape of the substrate is not particularly limited, and can be appropriately selected as circular, rectangular, etc., depending on the intended use of the finished sheet.

[0040] For example, when the sheet material is used for busbar applications with a low aspect ratio (thickness to width ratio) and a thickness of 0.5 mm or more, the cross-sectional shape of the substrate is preferably circular. This is advantageous in terms of processing flat conductors used for high-current conduction.

[0041] Furthermore, when using the sheet material for flat wire applications, the cross-sectional shape of the substrate is preferably rectangular rather than circular. This is because a circular substrate creates stress concentration in the center, which can easily lead to edge cracks and serpentine patterns during the calendering process used to form thin sheets. There is a possibility that the yield rate may not be improved due to the removal of these edge portions, and the cross-sectional shape of the calendered sheet may become a racetrack shape (curved on the sides), potentially resulting in no increase in the duty cycle when used directly for winding applications. Therefore, the sheet material according to the present invention is particularly advantageous for manufacturing flat wires with a high aspect ratio.

[0042] <2.4> Casting thickness of the substrate

[0043] In this invention, the casting thickness of the substrate is not particularly limited and can be appropriately designed according to the required characteristics of the finished sheet.

[0044] For example, when the sheet is used for electrode applications in a probe card and the thickness of the sheet obtained in the sheet forming process described later is assumed to be 0.025 to 0.050 mm, the thickness of the substrate is preferably 15 to 20 mm.

[0045] This is because, for example, when the casting thickness of the substrate is thinner than 15mm, the required machining depth (reduction) cannot be achieved, resulting in insufficient hardness. When the casting thickness of the substrate is thicker than 20mm, the machining limit is reached at a relatively thick stage, especially at the edges where cracking occurs severely. Therefore, this necessitates additional heat treatment steps, leading to increased manufacturing costs. Furthermore, since the increased difficulty in optimizing heat treatment conditions can lead to problems such as difficulty in achieving reproducibility, these issues need to be avoided.

[0046] <2.5> Casting speed of the substrate

[0047] In this invention, the casting speed of the substrate is not particularly limited and can be appropriately designed according to the required characteristics of the finished sheet.

[0048] For example, when the sheet is used as an electrode for a probe card, if the thickness of the sheet obtained in the sheet forming process described later is assumed to be 15 to 20 mm, the casting speed is preferably 50 to 1000 mm / min, more preferably 100 to 300 mm / min.

[0049] <3> Process (b): Sheet forming process (S200)

[0050] The sheet forming process is a process used to process a substrate to a specified thickness to form a sheet-like component (sheet).

[0051] This process includes at least a rolling process.

[0052] In this invention, there is no particular limitation on the number of times the calendering process is performed in this step. It can be appropriately designed by 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 that is the destination of this step.

[0053] <3.1> Calendering treatment

[0054] Calendering is a process in which a substrate is subjected to continuous force to make it thinner and longer.

[0055] Calendering is generally a method in which a pair of parallel rollers are rotated, and the component to be calendered passes between the rollers.

[0056] In this invention, the type of calendering process is not particularly limited; for example, cold calendering can be used.

[0057] In addition, in this invention, the thickness of the calendered substrate (as an intermediate or final product of the sheet) can be appropriately designed.

[0058] <3.2>Heat Treatment

[0059] In addition, in this process, if the substrate after calendering is calendered again, it is preferable to perform appropriate heat treatment beforehand.

[0060] In this invention, there are no particular limitations on the conditions (heating temperature, heating time, etc.) for the heat treatment before recalendering.

[0061] <4> Process (c): Annealing process (S300)

[0062] Annealing is a heating process used to eliminate residual stress in sheets that have been rolled to a specified thickness; it is known as annealing.

[0063] <4.1> Heating Temperature

[0064] From the viewpoint of not causing recovery or avoiding abnormal grain growth, the heating temperature in this process is preferably in the range of 200 to 500°C.

[0065] <4.2> Heating Time

[0066] The heating time in this process is not particularly limited as the optimal time varies depending on the heating temperature mentioned above. 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.

[0067] <4.2> Sheet thickness

[0068] In this invention, the thickness of the sheet after this process is not particularly limited, but when the sheet is used as an electrode for a probe card, it is preferably 0.025 to 0.050 mm.

[0069] <5> Other processes

[0070] The sheet material after process (c) can be processed into a suitable specified shape according to its final use.

[0071] For example, extremely fine flat wires can be formed by cutting sheets to a predetermined width (0.5–2 mm).

[0072] In addition, by processing the sheet into any shape, it can also be used as an electrode sheet for busbars or strip heaters, or for probe cards used in semiconductor inspection.

[0073] <6> Experimental Example

[0074] Using the manufacturing method involved in this invention, multiple test specimens were prepared, and the hardness (Vickers hardness) of the wires used for electrical property testing was measured using a Vickers hardness tester based on JIS Z2244.

[0075] The evaluation criteria are as follows.

[0076] [Evaluation Criteria]

[0077] 〇: Above 280HV

[0078] ×: Less than 280HV

[0079] Simultaneously, using the double-bridge method, the resistance of each test specimen was measured in an indoor environment controlled at 20℃ (±2℃), and the average conductivity (%IACS) was calculated. The distance between voltage terminals was 500mm.

[0080] The calculation results are shown in Table 2. The conductivity required for the electrodes used as probe cards is ≥38% IACS.

[0081] <6.1> Manufacturing conditions

[0082] The manufacturing conditions for each test specimen are set as shown in Table 1 below.

[0083] In addition, the details of each process are as follows.

[0084] [Table 1]

[0085]

[0086] (a) Substrate formation process: The raw materials are heated at 1000 to 1400°C to melt them, and a composition (molten metal) with the composition ratios in Table 1 is prepared.

[0087] The casting speed is 300 mm / min. The molten material (molten metal) is poured into the mold and cooled to room temperature within 10 minutes to cast a base material A with a thickness or diameter of 6 to 14.3 mm.

[0088] (b) Sheet forming process: The substrate A is 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 the rolled substrate B.

[0089] Then, the calendered substrate B is heated in an N2 atmosphere at 370–450°C for 2400 minutes. The calendered substrate B is then further cold-calendered from a thickness of 1.83–4.56 mm to a thickness of 0.05–0.6 mm to produce a sheet C with the desired thickness.

[0090] (c) Annealing process: The sheet C is annealed at 200°C for 60 minutes in an N2 atmosphere to obtain test specimens 1 to 10.

[0091] <6.2> Measurement Results

[0092] The test results for each test subject are shown in Table 2.

[0093] [Table 2]

[0094] evaluate Experiment 1 Experiment 2 Experiment 3 Experiment 4 Experiment 5 Experiment 6 Experiment 7 Experimental subject 8 Experimental subject 9 Experimental subject 10 Vickers hardness (HV) 267 292 304 286 286 286 317 320 conductivity (%IA(S)) 69.2 60.7 63.4 68.5 62.6 61.8 62.3 57.5 determination × × ○ ○ × ○ ○ ○ ○ ○

[0095] <6.3> Verification Results

[0096] As shown in Table 2, the sheets involved in test subjects 3-4 and 6-10 can achieve the Vickers hardness (above 280 HV) and conductivity (above 38% IACS) required for use as electrode sheets in probe cards.

[0097] Explanation of symbols

[0098] S100: Substrate Forming Process

[0099] S200: Sheet Forming Process

[0100] S300: Annealing process

[0101] A: Substrate

[0102] B: Calendered substrate

[0103] C: Sheet

Claims

1. A method for manufacturing a copper-silver alloy sheet, characterized in that, The method comprises at least: (a) a step of obtaining a substrate with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy, wherein the continuously cast copper-silver alloy comprises 70 to 92% by mass of copper, 8 to 30% by mass of silver and 0 to 1% by mass of the balance containing unavoidable impurities; (b) a step of performing at least one rolling process on the substrate to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing an annealing process on the sheet, wherein the sheet after step (c) has a conductivity of 38% IACS or higher and a Vickers hardness of 280 HV or higher.

2. A method for manufacturing a copper-silver alloy sheet, characterized in that, The method includes at least: (a) a process of obtaining a substrate with a thickness or diameter of 6-30 mm by continuous casting of a copper-silver alloy, wherein the continuously cast copper-silver alloy comprises: 70-92% by mass of copper, 8-30% by mass of silver, and 0-1% by mass of the balance containing unavoidable impurities; (b) a process of subjecting the substrate to at least one rolling process to obtain a sheet with a thickness of 0.01-0.10 mm; and (c) a process of subjecting the sheet to an annealing process. The casting speed in (a) is 50~1000 mm / min. The heat treatment in (c) is carried out at a temperature of 200~500℃ for a duration of 60~4500 minutes. For the sheet material described in (c), the conductivity is ≥38% IACS and the Vickers hardness is ≥280HV.

3. The method for manufacturing the copper-silver alloy sheet according to claim 1 or 2, wherein, In (a), the sheet processed by (c) has a conductivity of 57.5% IACS or higher.

4. A method for manufacturing an electrode sheet for a probe card, characterized in that, The method includes at least: (a) a process of obtaining a substrate with a thickness or diameter of 6-30 mm by continuous casting of a copper-silver alloy, wherein the continuously cast copper-silver alloy comprises: 70-92% by mass of copper, 8-30% by mass of silver, and 0-1% by mass of the balance containing unavoidable impurities; (b) a process of subjecting the substrate to at least one rolling process to obtain a sheet with a thickness of 0.01-0.10 mm; and (c) a process of subjecting the sheet to an annealing process. For electrode sheets formed from the sheet described in (c), the conductivity is 38% IACS or higher and the Vickers hardness is 280 HV or higher.

5. A method for manufacturing an electrode sheet for a probe card, characterized in that, The method includes at least: (a) a process of obtaining a substrate with a thickness or diameter of 6-30 mm by continuous casting of a copper-silver alloy, wherein the continuously cast copper-silver alloy comprises: 70-92% by mass of copper, 8-30% by mass of silver, and 0-1% by mass of the balance containing unavoidable impurities; (b) a process of subjecting the substrate to at least one rolling process to obtain a sheet with a thickness of 0.01-0.10 mm; and (c) a process of subjecting the sheet to an annealing process. The casting speed in (a) is 50~1000 mm / min. The heat treatment in (c) is carried out at a temperature of 200~500℃ for a duration of 60~4500 minutes. For an electrode sheet formed from the sheet as described in (c), the conductivity is ≥38% IACS and the Vickers hardness is ≥280HV.

6. The method for manufacturing the electrode sheet of the probe card according to claim 4 or 5, wherein, In (a), the sheet processed by (c) has a conductivity of 57.5% IACS or higher.

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