Alloy material for probe

Abstract

[Problem] To provide an alloy material for a probe that can suppress the diffusion of solder and probe material components from the circuit connection of the object being probed during probe detection. [Solution] An alloy material for a probe, characterized by comprising 15-60% by mass of Pd, 3-79.9% by mass of Cu, 0.1-75% by mass of Ni and / or Pt.

Description

Technical Field

[0001] This invention relates to an alloy material for probes (hereinafter referred to as "probe material") used for detecting the electrical characteristics of integrated circuits or liquid crystal display devices on semiconductor wafers. Prior Technology

[0002] In testing the electrical characteristics of integrated circuits or liquid crystal display devices formed on semiconductor wafers, sockets or probe cards equipped with multiple probes are used. This testing is performed by bringing the probes assembled in the sockets or probe cards into contact with the electrodes or terminals or conductive parts of the integrated circuits or liquid crystal display devices.

[0003] This type of probe requires low contact resistance and the hardness to withstand repeated contact. In terms of probe material, beryllium copper alloy, tungsten, tungsten alloy, platinum alloy, palladium alloy, etc., are used.

[0004] Patent document 1 discloses a palladium alloy (hereinafter referred to as AgPdCu alloy) consisting of 16% to 50% copper, about 35% to about 59% palladium, and 4% or more silver. [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] US Patent No. 1935897 Specification Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] Previously, AgPdCu alloys, known for their excellent workability and precipitation hardening properties, were used as probe materials due to their shape stability and low resistivity. However, when used in circuit connections employing solder (such as Sn-Bi-based solder), the following issues arise: During testing, the probe repeatedly contacts and is energized with the solder. This Joule heating and the diffusion of solder components (such as Sn) with the probe material components lead to faster wear of the probe tip. In such cases, sudden or gradual changes in contact resistance can cause detection failures, necessitating cleaning or replacement of the contact tip, thus reducing the efficiency of the testing process.

[0008] Therefore, there is a strong demand for the development of probe materials with solder resistance that can inhibit the diffusion of solder components.

[0009] The purpose of this invention is to provide a probe material that can suppress the diffusion of solder and probe material components from the circuit connection of the object being tested during probe testing. [Methods used to solve problems]

[0010] The present invention was completed by discovering a probe material characterized by containing 15-60% by mass of Pd, 3-79.9% by mass of Cu, 0.1-75% by mass of Ni and / or Pt. [Effects of the Invention]

[0011] According to the present invention, a probe material can be provided that suppresses the diffusion of solder and components of the probe material from the circuit connection of the object being tested during testing. Simple Explanation of the Diagram

[0012] none. Implementation

[0013] [The form in which the invention is carried out]

[0014] The present invention relates to a probe material, characterized by comprising 15-60% by mass of Pd, 3-79.9% by mass of Cu, 0.1-75% by mass of Ni and / or Pt (in the case of containing Ni and Pt, the total is 0.1-75% by mass).

[0015] Pd-based materials exhibit excellent corrosion resistance, but their resistance becomes insufficient when the content is less than 15% by mass. On the other hand, if Pd exceeds 60% by mass, it becomes unsuitable because it cannot adequately suppress the diffusion of solder and probe materials.

[0016] In other states, the Pd content can be 17-55% by mass. Also, in other states, the Pd content can be 20-50% by mass.

[0017] Cu-based alloys have low resistivity and, when alloyed with Pd, can improve hardness. However, excessive addition reduces corrosion resistance. Therefore, less than 3% by mass does not provide sufficient hardness, while more than 79.9% by mass reduces corrosion resistance.

[0018] In other forms, the Cu content can be 5-74% by mass.

[0019] Ni and / or Pt can improve the solder resistance of alloys by being added to them. According to experiments, when the content is less than 0.1% by mass, it becomes insufficient to suppress the diffusion of solder and probe material components, while when it is greater than 75% by mass, it becomes unsuitable due to the increase in resistivity.

[0020] As other samples, the content of Ni and / or Pt can be 0.3 to 70% by mass (in the case of Ni and Pt, the total content is 0.3 to 70% by mass). Also, as other samples, the content of Ni and / or Pt can be 0.5 to 65% by mass (in the case of Ni and Pt, the total content is 0.5 to 65% by mass).

[0021] In the alloy of this invention, the key is to suppress the wear of the probe tip due to the diffusion of components between the solder and the probe material; the hardness does not need to reach the level of existing AgPdCu alloys. That is, since the solder (e.g., Sn-Bi-based solder) that the probe contacts has relatively low hardness, a hardness of 200 HV or higher is sufficient for the probe material.

[0022] In the alloy of the present invention, the diffusion of the components of the solder and the probe material is suppressed, presumably due to the following reasons. That is, it is believed that the Ni and / or Pt added to the probe material form a thin and dense intermetallic compound layer such as Sn-Ni and / or Sn-Pt at the interface where the solder and the probe contact. This intermetallic compound layer has the effect of hindering the diffusion of the components of the solder and the probe material, thus preventing the probe tip from being easily worn away. [Example]

[0023] Embodiments of the present invention will be described. The composition and properties of the alloys of the embodiments and comparative examples are shown in Table 1.

[0024] First, Pd, Cu, Ni, and Pt are blended into the composition shown in Table 1, and then melted in an argon gas environment using an electric arc melting method to produce various alloy ingots.

[0025] The aforementioned alloy ingots were repeatedly rolled and heat-treated to produce plates with a rolling ratio of 75% [=((thickness before rolling - thickness after rolling) / thickness before rolling)×100], which were used as test pieces for evaluating hardness and solder resistance. Furthermore, resistivity was measured using plates with a rolling ratio of 90% [=((thickness before rolling - thickness after rolling) / thickness before rolling)×100] as test pieces.

[0026] The test pieces of each alloy were evaluated as follows, and the results are shown in Table 2.

[0027] The hardness was measured at the center of the cross-section of the test piece using a Micro-Vickers hardness tester with a load of 200 gf and a holding time of 10 seconds.

[0028] Solder resistance was assessed by placing Sn-Bi based solder on a fabricated test piece and heat-treating it at 250°C for 1 hour in a N2 gas environment to melt the solder. After heat treatment, the test piece was embedded in resin, exposing the cross-section. The interface between the solder and the test piece was analyzed vertically using EPMA. The thickness of the diffusion layer, where Sn from the solder and Pd from the alloy coexist, was measured.

[0029] The thinner the measured diffusion layer thickness, the higher the solder resistance. Alloys with a diffusion layer thickness less than 100 μm are rated ◎, 100~200 μm are rated ○, 200μm~500 μm are rated △, and alloys greater than 500 μm are rated ×. The evaluation results are shown in Table 2. However, in cases where the diffusion layer thickness is 800 μm or more, since the diffusion layer forms almost the entirety of the tested solder, it is always recorded as 800 μm.

[0030] The resistivity is determined by measuring the resistance of each sample at room temperature and calculated according to Equation 1. Equation 1: Resistivity = (Resistance × Cross-sectional Area) / Measurement Length

[0031] [Table 1] Table 1 Composition (mass %) No. Pd Cu Ni Pt Ag In Example 1 48 twenty two 30 0 0 0 Example 2 45 30 25 0 0 0 Example 3 45 45 10 0 0 0 Example 4 45 50 5 0 0 0 Example 5 35 45 20 0 0 0 Example 6 35 55 10 0 0 0 Example 7 35 64 1 0 0 0 Example 8 35 64.5 0.5 0 0 0 Example 9 30 40 30 0 0 0 Example 10 25 65 10 0 0 0 Example 11 25 74 1 0 0 0 Example 12 45 30 0 25 0 0 Example 13 45 5 0 50 0 0 Example 14 45 40 10 5 0 0 Example 15 45 20 30 5 0 0 Example 16 45 5 25 25 0 0 Example 17 25 73 1 1 0 0 Example 18 25 60 10 5 0 0 Example 19 20 10 10 60 0 0 Example 20 25 25 5 45 0 0 Comparative Example 1 45 30 0 0 24.5 0.5 Comparative Example 2 45 55 0 0 0 0 Comparative Example 3 75 15 10 0 0 0

[0032] [Table 2] Table 2 No. resistivity μΩ·cm hardness HV Thickness of diffusion layer μm Diffusion layer thickness assessment Example 1 50 340 10 ◎ Example 2 60 300 10 ◎ Example 3 30 290 20 ◎ Example 4 20 280 20 ◎ Example 5 50 280 20 ◎ Example 6 20 270 20 ◎ Example 7 20 250 20 ◎ Example 8 20 240 70 ◎ Example 9 60 300 10 ◎ Example 10 20 240 20 ◎ Example 11 20 210 20 ◎ Example 12 70 280 190 ○ Example 13 50 250 80 ◎ Example 14 50 280 20 ◎ Example 15 50 340 10 ◎ Example 16 40 380 10 ◎ Example 17 20 210 60 ◎ Example 18 30 250 20 ◎ Example 19 60 390 10 ◎ Example 20 70 330 10 ◎ Comparative Example 1 20 350 600 × Comparative Example 2 20 270 800 × Comparative Example 3 40 290 800 ×

[0033] The results above show that the alloy system produced by this invention has high solder resistance and also possesses the hardness and resistivity required for probe materials. Therefore, this invention provides a material suitable for use as a probe material with solder resistance.

[0034] none

Claims

1. An alloy material for a probe, characterized in that it is composed of 15-60% by mass of Pd, 3-79.9% by mass of Cu, and 0.1-75% by mass of Ni, or composed of 15-60% by mass of Pd, 3-79.9% by mass of Cu, and 0.1-75% by mass of Pt, or composed of 15-60% by mass of Pd, 3-79.9% by mass of Cu, and a total of 0.1-75% by mass of Ni and Pt in the case where both Ni and Pt are present.

2. The alloy material used for the probe in Request 1 shall have a hardness of at least 210~390 HV.

3. The probe alloy material of claim 1 or 2, wherein when the probe alloy material and solder are heat-treated at 250°C for 1 hour, the thickness of the diffusion layer is less than 200 μm and has solder resistance.