JP7260910B2 - Materials for probe pins and probe pins - Google Patents

Description

The present invention relates to a probe pin (hereinafter abbreviated as "probe pin") for inspecting electrical characteristics of integrated circuits on semiconductor wafers, liquid crystal display devices, and the like.

2. Description of the Related Art Probe pins are used to inspect electrical characteristics of integrated circuits, liquid crystal display devices, and the like formed on semiconductor wafers. This inspection is performed by bringing probe pins incorporated in sockets or probe cards into contact with electrodes, terminals, and conductive portions of integrated circuits, liquid crystal display devices, and the like.

Hardness is important for such a probe pin because it is repeatedly brought into contact with an object to be inspected. The reason why hardness is important is that it is necessary to reduce wear due to the probe pins contacting the test object tens of thousands of times. Since the hardness required here is very effective in suppressing wear of the probe pin, the harder the probe pin, the better.

Materials used for contact probe pins include beryllium-copper alloys, tungsten, and tungsten alloys, but they are easily oxidized and may cause poor conduction due to oxide films or adhesion of oxide films to the test object. Gold plating may be used to prevent oxidation, but there are problems such as peeling of the plating.

In order to prevent defects due to the formation of an oxide film on the probe pin, as in Patent Documents 1 to 7, a platinum alloy, palladium alloy, or other base material that is difficult to oxidize may be used.

Patent No. 4216823 Patent No. 4878401 Patent No. 4176133 Japanese Patent Application Laid-Open No. 2004-93355 Patent No. 5657881 International publication number WO2014/021465 JP 2017-25354

Since the probe pins used have various shapes, they are subjected to rolling, drawing, bending, cutting, and the like. For this reason, probe pins are desired to be made of a material that has age-hardening ability so that the hardness can be controlled after processing.

Among the above documents, the platinum alloy of Patent Document 1 has a composition that does not age harden, so it is difficult to control the hardness, although solution hardening and work hardening can be used to increase the hardness.

AgPdCu-based alloys in Patent Documents 2 to 7 can be controlled in hardness by age hardening.

In the AgPdCu-based alloy as described above, depending on the shape of the probe pin, processing such as bending may be applied after aging. In that case, when working after aging, the maximum hardness at the time of aging breaks during working, so it is necessary to suppress the hardness after aging, but it is desirable to suppress the decrease in hardness when workable as much as possible.

The hardness of AgPdCu alloys can be controlled by age hardening, but after aging, it becomes difficult to work such as bending. If a large amount of additive element is added for the purpose of improving hardness, plastic workability decreases in inverse proportion to the improvement in hardness. Therefore, there is a demand for a probe pin material having an improved balance between hardness and workability after aging.
That is, the object of the present invention is to provide a probe pin material which has high hardness when aged and can be processed after age hardening, so that it can be applied to a case where processing such as bending is applied after age hardening. be. Another object of the present invention is to provide a probe pin manufactured using such a probe pin material.

In AgPdCu-based alloys, as a result of research on a composition that "has good plastic workability and can improve hardness after aging" and "has high hardness during aging and can be worked afterward", AgPdCu alloy By adding In, Ga, and B (boron) to the alloy, we have developed an alloy that satisfies the above requirements.

For the above-mentioned purposes, the probe pin material consisting of 19 to 37 mass% Ag, 39 to 50 mass% Pd, 23 to 35 mass% Cu, 0.1 to less than 1.0 mass% In, 0.1 to 0.6 mass% Ga, and 0.03 to 0.3 mass% B achieved by

Further, the above object is achieved by a probe pin manufactured using the probe pin material described above.

Further, in the probe pin material of the present invention, the hardness after aging may be Vickers hardness HV480 or more.

Further, in the use of the probe pin material of the present invention, the hardness after aging may be Vickers hardness HV 350 or more in the application of working after aging.

The present invention provides a probe pin material and a probe pin having good workability before aging and hardness of HV480 or more after aging or hardness of HV350 or more when workability after aging is improved. be able to.

The probe pin material of the present invention contains 19 to 37 mass% Ag, 39 to 50 mass% Pd, 23 to 35 mass% Cu, 0.1 to less than 1.0 mass% In, 0.1 to 0.6 mass% Ga, and 0.03 B. ~0.3mass%, and the alloy consists of a total of 100mass% together with unavoidable impurities.

It is preferable that Ag is 20-36 mass%, Pd is 40-48 mass%, Cu is 25-35 mass%, In is 0.2-0.9 mass%, Ga is 0.1-0.5 mass%, and B is 0.05-0.2 mass%.

The reason why the probe pin material of the present invention is a material that "has good plastic workability and can improve hardness after aging" and "has high hardness after aging that can be processed" is as follows. think like this.
AgPdCu alloy separates into a silver-rich phase and a copper-rich phase when it solidifies after melting. An ordered lattice phase (PdCu phase) is generated in the "rich phase" and the hardness increases. In has the effect of expelling Pd from the “silver-rich phase” and promoting the formation of an ordered lattice phase (PdCu phase), and Ga has the effect of promoting the formation of the PdCu phase. It is thought that the hardness of the alloy increases because it promotes the formation of the ordered lattice phase. On the other hand, it is believed that B improves the grain boundary strength and suppresses grain boundary fracture, thereby increasing the hardness after aging, which enables processing.

The alloy used for the probe pin according to the present invention can be prepared according to a method known per se, for example by adjusting Ag, Pd, Cu, In, Ga and B in the amounts mentioned above, and then melting it into a suitable metal in a gas furnace, high frequency melting furnace or the like. It can be produced by melting in a melting furnace. As the furnace atmosphere during melting, air is usually used, but inert gas or vacuum can be used as necessary.

The molten alloy is cast into a suitable mold to produce an ingot. If necessary, the ingot is forged or swaged, processed into a plate by rolling, processed into a square or polygonal bar or wire by grooved rolls, and then wire-drawn using a die to produce a probe pin material. can be made.

The probe pin material of the present invention can be hardened by heat treatment in the range of 300 to 450° C. after being processed into a predetermined probe pin shape by age hardening. Hardness of HV480 or higher can be achieved by age hardening.

Further, the probe pin material of the present invention can have a Vickers hardness HV of 350 or more after aging in applications where processing is performed after aging. That is, when processing such as bending is performed after aging to form a probe pin shape, aging is performed at a predetermined temperature, and then processing such as bending 90° is performed to obtain the probe pin shape. The predetermined temperature may be in the range of 400 to 650° C., depending on the material composition, material shape, and processing conditions.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples.

Ag, Pd, Cu, In, Ga, and B were blended to 30 g per sample, melted in an arc melting furnace, and cast to produce an ingot. Table 1 shows the compositions prepared.

In order to determine the workability of the samples in Table 1, the ingots were heat-treated at 850°C for 60 minutes, then water-cooled, rolled, heat-treated, and rolled repeatedly, rolled to a thickness of 2.5 mm, and again at 850°C for 60 minutes. After heat treatment, it is water-cooled and rolled to t0.3mm so that the rolling ratio [= ((thickness before rolling) - (thickness after rolling)) / (thickness before rolling) x 100] is 88%. gone.
The workability was evaluated by the rolling conditions. As the evaluation criteria, ∘ indicates that rolling was possible without large cracks, and x indicates that cracks occurred without being rolled to t2.5 mm. Table 2 shows the evaluation results.

Examples in Table 2 could be rolled without particular problems. In Comparative Example 3, in which a large amount of B was added, cracks occurred during rolling up to t2.5 mm, and the subsequent rolling was difficult, and was marked as x. Subsequent investigations were discontinued for the samples marked with x. It can be seen that the addition of a large amount of B makes plastic working difficult.

・Hardness test The hardness after rolling of the samples marked with ○ from the workability evaluation results in Table 2 was measured, followed by heat treatment in the range of 300 to 450°C for 1 hour, and the hardness after aging was measured. Table 3 shows the measurement results. The hardness after aging in Table 3 is the hardest value when aging is performed in the temperature range of 300 to 450°C.

When the rolling reduction was 88%, all the samples produced had a hardness of HV480 or higher after aging.

・Investigation of bending work The hardness after rolling of the samples marked with ○ from the workability evaluation results in Table 2 was measured, and then heat-treated for 1 hour in the range of 400 to 650°C for age hardening. , sandwiched between R0.2 chamfered carbon steel blocks with a vise, bent 90°, and measured the maximum hardness without breaking. Table 4 shows the measurement results.

The maximum hardness after aging without breaking at 90° bending was HV350 or more for all the examples. On the other hand, the comparative example did not reach HV350, and the hardness of comparative example 1 was lower than that at the time of rolling.

Claims (2)

Probe pin material consisting of 19 to 37 mass% Ag, 39 to 50 mass% Pd, 23 to 35 mass% Cu, 0.1 to less than 1.0 mass% In, 0.1 to 0.6 mass% Ga, and 0.03 to 0.3 mass% B. A probe pin produced using the probe pin material according to claim 1.