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

Abstract

Provided are: a copper-silver alloy sheet having excellent hardness; and a sheet for an electrode of a probe card using the same. The method for producing a sheet made of a copper-silver alloy at least comprises (a) a step for obtaining a base material having a thickness or a diameter of 6-30 mm by continuous casting of a copper-silver alloy, (b) a step for obtaining a sheet having a thickness of 0.01-0.10 mm by subjecting the base material to at least one or more rolling treatments, and (c) a step for subjecting the sheet to an annealing treatment.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a sheet made of a copper-silver alloy and a method for manufacturing a sheet for an electrode of a probe card. More specifically, the present invention relates to a method for manufacturing a sheet made of a copper-silver alloy having excellent hardness and a method for manufacturing a sheet for an electrode of a probe card. Background Art

[0002] As one of the methods for manufacturing various components and members using a copper-silver alloy, a method for manufacturing an extremely fine copper alloy wire having strength, high conductivity, and being difficult to reduce in strength even under a thermal load and having excellent heat resistance is disclosed in Patent Document 1 below.

[0003] In addition, in Patent Document 2 below, a method for manufacturing a copper alloy capable of obtaining high strength and high conductivity is disclosed.

[0004] Prior Art Documents

[0005] Patent Documents

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

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

[0008] Problems to be Solved by the Invention

[0009] The applicant focused on the characteristics of a copper-silver alloy having high conductivity and conceived to produce a sheet for an electrode used in a semiconductor inspection probe card.

[0010] However, the electrode sheet used in a semiconductor inspection probe card requires high hardness, and a sheet made of a copper-silver alloy having sufficient hardness has not yet appeared.

[0011] Therefore, an object of the present invention is to obtain a sheet made of a copper-silver alloy having excellent hardness and a sheet for an electrode of a probe card.

[0012] Means for Solving the Problems

[0013] A preferred aspect of the present invention completed to solve the above problems is a method for manufacturing a sheet made of a copper-silver alloy, which is characterized in that the method includes at least: (a) a step of obtaining a base material having a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy, (b) a step of performing at least one or more rolling treatments on the base material to obtain a sheet having a thickness of 0.01 to 0.10 mm, and (c) a step of performing an annealing treatment on the sheet. For the sheet after the step (c), the Vickers hardness is 280 HV or more.

[0014] Further, another aspect of the present invention is a method for manufacturing an electrode sheet for a probe card, characterized in that the method at least includes: (a) a step of obtaining a base material with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy, (b) a step of performing at least one or more rolling treatments on the base material to obtain a sheet with a thickness of 0.01 to 0.10 mm, and (c) a step of performing an annealing treatment on the sheet. For the electrode sheet formed from the sheet after the step (c), the Vickers hardness is 280 HV or more.

[0015] Effects of the present invention

[0016] According to the present invention, it is possible to obtain a sheet made of a copper-silver alloy and an electrode sheet for a probe card with excellent hardness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flowchart showing the steps of the method for manufacturing a sheet made of a copper-silver alloy according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

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

[0019] In this specification, in the "~" indicating a numerical range, the upper limit value and the lower limit value are included in the range.

[0020] EXAMPLES

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

[0022] The method for manufacturing a sheet made of a copper-silver alloy according to the present invention mainly includes at least a base material forming step, a sheet forming step, and an annealing step.

[0023] Hereinafter, the details of each step will be described.

[0024] <2> Step (a): Base material forming step (S100)

[0025] The base material forming step is a step for forming a base material made of a copper-silver alloy having a predetermined shape.

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

[0027] In the present 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 use of the completed sheet.

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

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

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

[0031] · Balance (including inevitable impurities): 0 to 1% by mass

[0032] <2.2> Method for forming the base material

[0033] In the present invention, the base material is preferably formed by a continuous casting method.

[0034] The continuous casting method refers to a method of cooling molten metal with a mold while slowly drawing it to solidify, thereby taking out a long-connected casting.

[0035] According to the continuous casting method, since the alloy constituent elements are easily uniformly dispersed, the solution treatment consisting of high-temperature heat treatment + quenching process can be omitted.

[0036] In addition, according to the continuous casting method, the structure control of the base material can be easily performed during continuous casting (for example: control of the grain diameter characteristic of the final shape of the sheet, control of the precipitation layer remaining at the grain boundary, etc.). Therefore, by appropriately managing this structure control, it is possible to expect that the pre-refined grain diameter is maintained until the final shape of the sheet, and the hardness and strength of the sheet are increased.

[0037] In addition, if the crystal grain size of the sheet can be reduced by appropriately managing the above structure, burr generation can be suppressed when cutting the sheet, and an improvement in the yield can also be envisaged.

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

[0039] In the present invention, the cross-sectional shape of the base material is not particularly limited, and it can be appropriately selected as circular, rectangular, etc. according to the use of the completed sheet.

[0040] For example, when the sheet is used for a bus bar application with a low aspect ratio (ratio of thickness to width) and a thickness of 0.5 mm or more, the cross-sectional shape of the base material is preferably circular. This is because it is beneficial for the processing of flat conductors for large current conduction.

[0041] In addition, when the sheet is used for the purpose of flat wire, the cross-sectional shape of the base material is preferably rectangular rather than circular. This is because, in a base material with a circular cross-sectional shape, stress concentration occurs at the center, and edge cracks and meandering are likely to occur during the rolling process for forming a thin sheet. There is a possibility that the yield rate is not increased due to the removal of the edge part, etc. The cross-sectional shape of the sheet after the rolling process becomes a runway shape (the side is a curved shape), and there is a possibility that the space factor is not increased when directly used for winding purposes. Therefore, the sheet according to the present invention is particularly advantageous for manufacturing a flat wire having a high aspect ratio.

[0042] <2.4> Casting thickness of the base material

[0043] In the present invention, the casting thickness of the base material is not particularly limited and can be appropriately designed according to the characteristics required for the completed sheet.

[0044] For example, when the sheet is used for the electrode of 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 base material is preferably 15 to 20 mm.

[0045] This is because, for example, considering that when the casting thickness of the base material is thinner than 15 mm, the processing degree (reduction) cannot be obtained, and there is a problem that the necessary hardness cannot be obtained. When the casting thickness of the base material is thicker than 20 mm, the processing limit is reached at a relatively thick stage, and particularly severe cracks occur at the edge part. Therefore, it leads to an increase in the heat treatment process and an increase in the manufacturing cost. In addition, since it can be expected that problems such as difficulty in obtaining reproducibility will occur due to the increase in the difficulty of optimizing the heat treatment conditions, it is necessary to avoid these problems.

[0046] <2.5> Casting speed of the base material

[0047] In the present invention, the casting speed of the base material is not particularly limited and can be appropriately designed according to the characteristics required for the completed sheet.

[0048] For example, when the sheet is used for the electrode of 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 / minute, more preferably 100 to 300 mm / minute.

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

[0050] The sheet forming process is a process for processing the base material into a specified thickness to form a sheet-like member (sheet).

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

[0052] In the present invention, the number of times of performing the calendering process in this step and the like are not particularly limited, and it may be appropriately designed as long as the thickness and characteristics of the base material as the starting point of this step and the thickness and characteristics of the sheet as the end point of this step are taken into consideration.

[0053] <3.1>Calendering process

[0054] The calendering process is a process of applying a continuous force to the base material as an object to make the base material thinner and extended.

[0055] The calendering process is generally a method of rotating a pair of rolls placed in parallel and passing a member to be calendered between the pair of rolls.

[0056] In the present invention, the type of the calendering process is not particularly limited, and for example, cold calendering or the like can be used.

[0057] In addition, in the present invention, the thickness of the base material (as an intermediate product or a final product of the sheet) after the calendering process can be appropriately designed.

[0058] <3.2>Heating process

[0059] In addition, in this step, when the base material after the calendering process is calendered again, it is preferable to perform an appropriate heating process in advance.

[0060] In the present invention, the conditions (heating temperature, heating time, etc.) of the heating process before the re-calendering are not particularly limited.

[0061] <4>Step (c): Annealing step (S300)

[0062] The annealing step is a heating step for eliminating residual stress in the sheet formed to a specified thickness by the calendering process, and is a step called so-called annealing.

[0063] <4.1>Heating temperature

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

[0065] <4.2>Heating time

[0066] The heating time in this step is not particularly limited because the optimal time changes according to the above heating temperature, but when the heating temperature is in the range of 200 to 500 °C, it is preferably in the range of about 60 to 4500 minutes.

[0067] <4.2>Thickness of the sheet

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

[0069] <5>Other processes

[0070] The sheet that has undergone step (c) can be processed into an appropriate specified shape according to the final use.

[0071] For example, an extremely fine flat wire can be formed by cutting the sheet into a predetermined width (0.5 to 2 mm).

[0072] In addition, by processing the sheet into an arbitrary shape, it can also be used as a bus bar, a strip heater, or a sheet for the electrode of a probe card used in semiconductor inspection.

[0073] <6>Experimental examples

[0074] Using the manufacturing method according to the present invention, a plurality of test specimens were produced, and the hardness (Vickers hardness) of each wire for electrical property inspection was measured using a Vickers hardness tester based on JIS Z2244.

[0075] The evaluation criteria are as follows.

[0076] [Evaluation criteria]

[0077] 〇: 280 HV or more

[0078] ×: Less than 280 HV

[0079] At the same time, using the double-bridge method, the resistance of each test specimen was measured in a room controlled at 20 °C (±2 °C), and the average values of the conductivity (%IACS) were calculated. The distance between the voltage terminals was 500 mm.

[0080] The calculation results are shown in Table 2. The conductivity required for the sheet for the electrode of a probe card is 38% IACS or more.

[0081] <6.1>Manufacturing conditions

[0082] The manufacturing conditions of each test specimen were 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 step: The raw material is heated and melted at 1000 to 1400 °C to prepare a composition (molten metal) having the composition ratio shown in Table 1.

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

[0088] (b) Sheet forming process: The base material A is cold-rolled from a thickness or diameter of 6 - 14.3 mm to a thickness of 1.83 - 4.56 mm to produce a rolled base material B.

[0089] Then, the rolled base material B is heated in an N 2 gas atmosphere at 370 - 450 °C for 2400 minutes. Then, the rolled base material B is further cold-rolled 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 in an N 2 gas atmosphere at 200 °C for 60 minutes to obtain test specimens 1 - 10.

[0091] <6.2> Measurement results

[0092] The measurement results of each test specimen are shown in Table 2.

[0093] [Table 2]

[0094] Evaluation Subject 1 Subject 2 Subject 3 Subject 4 Subject 5 Subject 6 Subject 7 Subject 8 Subject 9 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 Judgment × × ○ ○ × ○ ○ ○ ○ ○

[0095] <6.3> Verification results

[0096] As shown in Table 2, the sheets related to test specimens 3 - 4 and test specimens 6 - 10 can achieve the Vickers hardness (280 HV or more) and conductivity (38% IACS or more) required for the electrode sheet of a probe card.

[0097] Explanation of symbols

[0098] S100: Base material forming process

[0099] S200: Sheet forming process

[0100] S300: Annealing process

[0101] A: Base material

[0102] B: Rolled base material

[0103] C: Sheet

Claims

1. A manufacturing method of a sheet made of a copper-silver alloy, characterized in that, the method at least includes: (a) a step of obtaining a base material with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) a step of performing at least one rolling treatment on the base material to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing annealing treatment on the sheet, for the sheet after the step (c), the Vickers hardness is 280 HV or more.

2. A manufacturing method of a sheet made of a copper-silver alloy, characterized in that, the method at least includes: (a) a step of obtaining a base material with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) a step of performing at least one rolling treatment on the base material to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing annealing treatment on the sheet, the silver content in the copper-silver alloy is 8 to 30% by mass, the casting speed in the step (a) is 50 to 1000 mm / minute, the heating temperature of the heat treatment in the step (c) is 200 to 500 °C, and the heating time is 60 to 4500 minutes, for the sheet after the step (c), the Vickers hardness is 280 HV or more.

3. The manufacturing method of a sheet made of a copper-silver alloy according to claim 1 or 2, wherein, in the step (a), the cross-sectional shape of the base material is a rectangular shape.

4. A manufacturing method of a sheet for an electrode of a probe card, characterized in that, the method at least includes: (a) a step of obtaining a base material with a thickness or diameter of 6 to 30 mm by continuous casting of a copper-silver alloy; (b) a step of performing at least one rolling treatment on the base material to obtain a sheet with a thickness of 0.01 to 0.10 mm; and (c) a step of performing annealing treatment on the sheet, for the sheet for an electrode formed from the sheet after the step (c), the Vickers hardness is 280 HV or more.

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

6. The manufacturing method of a sheet for an electrode of a probe card according to claim 4 or 5, wherein, in the step (a), the cross-sectional shape of the base material is a rectangular shape.

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