JPH04180531A - Electrically conductive material - Google Patents

Abstract

PURPOSE:To obtain an electrically conductive material having high electrical conductivity and superior migration resistance by regulating the oxygen content of a Cu alloy contg. prescribed amts. of Si and other added element such as Ni and the size of a precipitate formed by aging. CONSTITUTION:The oxygen content of an alloy consisting of 0.05-3.0wt.% Si, 0.1-5.0wt.% one or more among Ni, Fe, Co, Cr and Ti and the balance Cu with inevitable impurities is regulated to <=20ppm and the size of a precipitate formed by aging is regulated to <=2mum to obtain the above-mentioned material. About 0.001-5.0wt.%, in total, of one or more among Zn, Sn Mg, Mn, Al, B, P, As and Sb as secondary components may further be added to the above- mentioned compsn. as required. The grain size of the obtd. material is preferably about <=30mum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current-carrying material for electrical component materials that suppresses migration between lead frames, terminals, connectors, and bus bars (also referred to as bus bars).

[Conventional technology]

BACKGROUND ART In recent years, electronic and electrical equipment, etc. have become smaller and lighter, and the parts used, such as connectors, have also become smaller, and the distances between parts have tended to become significantly shorter.

Also, circuits are becoming increasingly integrated. In other words, in the past, individual electronic components were connected by lead wires to form a circuit, but as the number of components increases, circuits become more complex, so circuits are becoming smaller by integrating them. There is.

[Problem to be solved by the invention] In conventional miniaturized and integrated circuits, different circuits or wiring are separated by a small interval for miniaturization. When an electrolyte is present, an electrochemical reaction occurs, and copper ions melted from the copper alloy that is the material of the current-carrying part on the high potential side are deposited on the low potential side, and when the amount increases further, a short circuit occurs. This phenomenon is called migration, and when such migration occurs, the circuit no longer functions properly. Therefore, in recent years, there has been a strong desire for materials that have high electrical conductivity and do not cause migration.

[Means for solving the problem]

In view of the above-mentioned problems, the present inventors have conducted research on migration, and have used 810.05 to 3.0 wt% as current-carrying materials for terminals, connectors, bus bars, etc. connected to the anode side.
and further contains one or more of Ni, Fe, Co, Cr, and Ti in a total amount of 0.1 to 5.0 wt%,
The oxygen content of the alloy consisting of the balance Cu and unavoidable impurities is 20 PPm or less, and there are precipitates due to aging treatment, and the size of the precipitates is 2 μm or less,
Or Si0.05~3.0wt%, further N1, F
e, Co, Cr, and Ti in a total amount of 0.1 to 5. Contains Qwt%, Zn and Sn as subcomponents
, Mg, Mn, Al, B, P, As, and sb in a total amount of 0.001 to 5.0 wt%, and the balance is Cu and unavoidable impurities. 20 ppm or less, the presence of precipitates due to aging treatment, the size of the precipitates is 2 μm or less, and the crystal grain size of the alloy is 3 μm or less.

[Detailed description of the invention]

According to the present invention, the amount of each element added to Cu is determined in consideration of the following.

That is, first of all, Si is an element that has the effect of suppressing the migration property of copper and copper alloys by being contained in copper and copper alloys.

Although the mechanism that suppresses the migration phenomenon is not clear, the presence of Sl reduces the amount of Cu ions eluted and increases the
It is presumed that the generation of the compound prevents the conduction of electricity through the deposited Cu particles, thereby suppressing the migration phenomenon between the electrodes.

The reason why the Si content is set to 0.05 to 3 Owt% is that if the S1 content is less than 0.05wt%, there is no effect of suppressing the migration phenomenon, and if it exceeds 3.0wt%, the effect of suppressing the migration phenomenon is reduced. However, this is because the electrical conductivity decreases, the amount of heat generated when electricity is applied increases, and the heat dissipation performance also decreases.

The reason why the content of one or more of Ni, Fe, Co, Cr, and Ti is set to 0.1 to 5.0 wt%.

These elements have the effect of suppressing migration phenomena and also contribute to improving strength, but at 0.1 wt.
If the content is less than 5.0 wt%, the effect will be low, and if it exceeds 5.0 wt%, the conductivity will decrease significantly.

Furthermore, Zn, Sn, Mg, Mn, A1, B,
0.001 of one or more of P, As, and Sb
The reason for adding 5.0 wt% or more is to improve the strength, but if it is less than 0.001 wt%, there is no effect. This is because if it exceeds Owt%, the conductivity decreases.

The reason why the size of the precipitates is limited to 2 μm or less is that if the precipitates become coarse and have a size exceeding 2 μm, the microcrash phenomenon will suddenly occur.

What is the reason for setting the oxygen content to 20 ppm or less?

This is because it has been found that if Si is captured as an oxide in the alloy, it does not contribute to improving migration properties. In other words, in an alloy with an oxygen content exceeding 20 ppm, Si is likely to be treated as an oxide. If Si oxide is generated, Si concentration is likely to occur there, resulting in a rapid decrease in migration properties. It is.

The reason why the crystal grain size is 30 μm or less is that the crystal grain size is 30 μm or less.
This is because when the grain size exceeds μm, there is a tendency for workability to decrease and migration performance to decrease by t.

〔Example〕

Specific examples of the present invention are shown below.

First, the alloys of the present invention and comparative alloys having the compositions shown in Table 1 were melted and cast in an inert atmosphere, subjected to hot rolling after facing, and then cold rolled, annealed and pickled repeatedly, and then heated to a predetermined temperature of 400 to 600°C. The grain size was adjusted by final annealing for 3 hours, and after pickling, a plate with a thickness of 0.6 nyn was obtained which was cold rolled at a workability of 20%. Then, the surface was polished with 1200mm merry paper.

These test materials were evaluated for tensile strength, elongation, electrical conductivity, and migration resistance. To test the migration resistance, the test material was cut into lommXloomm pieces, set as a set of two pieces as shown in FIG. 1, and the test material was immersed in tap water (300 cc) as shown in FIG. 2. Next, a DC voltage of 14 V was applied to these two test materials, and the change in current value with respect to elapsed time was measured using a recorder. A typical example of this result is shown in FIG. Also, the current value in each sample material is 1. The time until OA (arrow in Figure 3) is the first
Shown in the table.

The size of the precipitates is 21 times the cross section of the sample material 1000 times.
The size of the largest precipitate was determined using ffll 2 microscopy.

From Table 1, alloys Nos. 1 to 7 of the present invention all have electrical conductivity of 40%lAC3 or higher, and are excellent in strength and migration resistance, and are suitable for use in lead frames, automotive terminals and connectors,
It can be seen that this alloy is optimal as a current-carrying material that requires migration resistance, such as in bus bars.

In addition, the comparative alloy Nα8 has S1 compared to the present invention alloy Na1.
Since the content is low, migration resistance is poor and strength is also low. Comparative alloy Nα9 has too much Si content and therefore has low electrical conductivity. Comparative alloy Nα10 is the invention alloy N
Since it has a higher oxygen content than α2, it has poor migration resistance. Comparative alloy Nα11 has too large precipitates compared to alloy NQ6 of the present invention, and therefore has poor migration resistance. Comparative alloy NQ12 has grains that are too large compared to invention alloy Nα5, and therefore has poor migration resistance. Comparative alloy N
α13 is a type of brass conventionally used for automobile bus bars and the like, and has high migration resistance but low electrical conductivity.

〔Effect of the invention〕

The current-carrying material of the present invention has high electrical conductivity and is a material with excellent migration resistance.

Margin below

[Brief explanation of drawings]

FIG. 1 is a perspective view of a sample material for a migration resistance test, FIG. 2 is an explanatory diagram of the test, and FIG. 3 is a graph showing the measurement results.

Claims (3)

[Claims] (1) Si0.05-3.0wt% and Ni, Fe, Co
, Cr, Ti or more from 0.1 to 5
．． A current-carrying material characterized in that an alloy containing 0 wt% and the balance consisting of Cu and unavoidable impurities has an oxygen content of 20 ppm or less, and has precipitates due to aging treatment, and the size of the precipitates is 2 μm or less. . (2) Si0.05-3.0wt% and Ni, Fe, Co
, Cr, Ti or more from 0.1 to 5
．． 0wt% and further subcomponents of Zn, Sn, Mg, M
Contains one or more of n, Al, B, P, As, and Sb in a total amount of 0.001 to 5.0 wt%, and the balance is C.
The oxygen content of the alloy consisting of u and inevitable impurities is 20p
pm or less, and there are precipitates due to aging treatment,
An electrically conductive material characterized in that the size of the precipitates is 2 μm or less. (3) The electrically conductive material according to items (1) or (2), characterized in that the crystal grain size is 30 μm or less.