JPH0356292B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is applicable to lead materials for semiconductors that require comprehensive properties such as heat resistance, electrical and thermal conductivity, solderability, plating properties, mechanical strength, spring properties, and repeated bendability. This invention relates to a copper alloy suitable for conductive members such as connectors and switches. [Prior art] In general, 42 alloy (Fe-42
%Ni alloy) have been used. However, with the spread of resin packages and progress in cost reduction, the use of copper alloys is rapidly increasing, and CDA194 alloy and phosphor bronze are mainly used. On the other hand, with the recent progress toward higher integration of ICs, highly conductive materials are desired.
In addition, with the progress of miniaturization and thinning to improve packaging density, improvements in strength and repeated bending characteristics are desired. On the other hand, CDA194 alloy, phosphor bronze, etc. have been used as copper alloys for electrical parts such as connectors and switches, but in order to reduce costs by making parts smaller and thinner, higher strength, conductivity, and springs are required. It is desired to have comprehensive characteristics such as characteristics. However, although CDA194 alloy has good conductivity and strength, its spring properties and heat resistance are somewhat low. Phosphor bronze has excellent strength, spring properties, and repeated bending properties, but has advantages and disadvantages, such as low heat resistance and low conductivity. . In general, as electric components such as semiconductor lead materials and connectors become smaller and thinner, the following properties are required of copper alloys. (1) It has excellent thermal and electrical conductivity (approximately evaluated by thermal conductivity and electrical conductivity), (2) It has high strength so that it will not twist or bend when thinned, ( 3) Must be able to withstand high temperature heating during die bonding and not easily soften; (4) Must be able to withstand repeated bending as a lead material; (5) Must have good soldering properties. Among these properties, as disclosed in JP-A-341253, Fe and Ti, Fe and Si or
Strongly conductive copper alloys manufactured using the precipitation of intermetallic compounds of Fe and Ni are known. here
For Cu-Fe-Ti ternary alloys, solution treatment at 1000°C and water quenching are essential to obtain their excellent strength and conductivity, and complex operations are required. [Problems to be Solved by the Invention] The purpose of the present invention is to eliminate the need for solution treatment at 1000°C and water quenching treatment, and to eliminate the need for ordinary hot rolling followed by shower water cooling, cold working, and aging precipitation treatment ( annealing)
Semiconductor lead materials and electrical components that have improved conductivity or greatly improved strength by minimizing the decrease in conductivity, and also improved spring characteristics, repeated bending characteristics, and heat resistance. The object of the present invention is to provide suitable copper alloys such as the following. [Means for solving the problem] According to the present invention, 0.1-1% by weight of Fe, 0.05-1% by weight
Contains 0.5% by weight of Ti, and more than 0.5% by weight and up to 2% by weight of Sn, with the remainder being substantially Cu and Fe.
Provided is a copper alloy for conductive members that has excellent conductivity, strength, heat resistance, and repeated bendability, and has a weight ratio Fe/Ti of 1.4 to 2.8. Further, according to the present invention, 0.1 to 1% by weight of
Contains Fe, 0.05 to 0.5 wt% Ti, more than 0.5 wt% to 2 wt% Sn, and 0.005 to 0.2 wt% Mg, the balance being substantially Cu, and the weight ratio of Fu to Ti is Fe. Provided is a copper alloy for conductive members that has excellent conductivity, strength, heat resistance, and repeated bendability, and is characterized in that /Ti is 1.4 to 2.8. In the following description, all percentages are by weight, but they are simply written as %. Next, the reason for adding the alloy components and the reason for limiting the range of the components will be explained. Fe and Ti improve the properties (strength, conductivity) that are the object of the present invention due to their synergistic effect. This is because Fe and Ti form a compound called Fe ₂ Ti, which is finely precipitated in the matrix by heat treatment. The excellent properties of the alloy of the present invention are basically due to the Fe
Since it is obtained by precipitation of a compound of Ti and
There is an appropriate ratio of Fe/Ti.
(weight ratio) of 1.4 to 2.8, more preferably 1.7 to 2.4. Regarding this weight ratio, the present inventors studied the Cu-Fe-Ti3 elements and obtained knowledge about the relationship between Fe/Ti conductivity and strength after aging precipitation treatment, as typified by the results shown in Figure 1. It is Fe/
When Ti is less than 1.4, the amount of excess Ti dissolved in the matrix increases and the conductivity decreases significantly.When it exceeds 2.8, the amount of excess Fe dissolved in the matrix increases and the conductivity decreases, but especially The decrease in tensile strength increases. When Ti is less than 0.05% and Fe is less than 0.1%, the effect of improving strength and softening resistance due to Fe ₂ Ti precipitates is small;
%, and even if Fe is added in excess of 1%, the improvement in properties is almost saturated. Sn dissolves in the Cu-Fe-Ti alloy and improves the strength of the Cu-Fe-Ti alloy through solid solution hardening, as well as its repeated bendability, heat resistance, and spring characteristics. Here, the amount of Sn added is 0.5
If it is less than 2%, the effect of improving bending properties and heat resistance strength will be small, while if it exceeds 2%, the electrical conductivity will decrease significantly. Like Sn, Mg forms a solid solution in Cu-Fe-Ti alloys, improving strength, heat resistance, and spring properties. If Mg is added in an amount less than 0.005%, these effects will be small, and even if it is added in an amount exceeding 0.2%, the strength will be saturated and the conductivity will decrease significantly. Next, the present embodiment will be explained. Example: Using a high-frequency melting furnace, electrolytic copper was melted in an aluminium crucible while covering the surface with charcoal powder, and electrolytic iron, sponge Ti, Sn ingot, Cu-50% Mg master alloy, etc. were added. It was cast into a mold with an inner diameter of 150 mm, and a billet with dimensions of 150 mm and 100 mm was produced. The compositions of these alloys and comparative alloys are shown in Table 1.
This billet was heated to 950°C and hot extruded to produce an extruded wire of 8.5 mmφ. Furthermore, this wire was drawn to 0.9 mmφ without intermediate annealing. The cold working at this time was good with no line breaks on the way.
The 0.9 mmφ wire was annealed at 500°C for 3 hours (aging precipitation treatment), and the tensile strength, elongation, and electrical conductivity before and after annealing were investigated. The results are also shown in Table 1.
A 90°C repeated bending test was also conducted on the annealed material. In this repeated bending test, the above wire is held vertically in a holder, a 1 kg weight is suspended from the lower end of the wire, the holder is bent down 90 degrees, and then returned to its original position and this is counted as one test. The bending direction is only one direction. This operation was repeated and the number of times until breakage occurred was measured. The results are also shown in Table 1. In addition, in order to compare the performance of the alloy of the present invention, commercially available CDA194 alloy and phosphor bronze with a thickness of 0.25
mm, tempered (H: hard) plate is also processed material (H
The properties of the raw material) and the annealed material (annealed at 500°C for 3 hours) were measured, and the results are shown in Table 1. However, repeated bending tests were not performed. Furthermore, the present invention alloys (No. 1 to 5) and the comparative alloy (No.
6 to 9) were annealed at each temperature for 1 hour, and the temperature at which the tensile strength becomes 1/2 of the sum of the initial tensile strength and the tensile strength after complete softening (semi-softening temperature) was investigated. This semi-softening temperature is also shown in Table 1. This semi-softening temperature is an index of heat resistance.

[Table] Next, the effects of the present invention will be explained with reference to Table 1. (1) Strength properties: The processed materials and annealed materials (aging precipitation treated materials) of the invention alloys (Nos. 1 to 5) are comparative alloy No.
Compared to the processed material of comparative alloy No. 8 (CDA194 alloy), the strength is significantly greater, and compared to the processed material of comparative alloy No. 9 (phosphor bronze), No. 1, which has lower concentrations of Fe, Ti, and Sn,
With the exception of 2, the results are the same or significantly higher. Next, when comparing the properties of Cu-Fe-Ti alloys, it is necessary to compare alloys containing the same amount of Ti, since the various property values vary depending on the amount of Ti. Contains almost the same amount of Ti as alloys No. 3 and 4 of the present invention, but does not contain Sn or Mg
Comparing No. 6, No. 6 contains Sn and Mg.
The improvements in characteristics 3 and 4 are remarkable. Comparative metal-containing No.
7 has an Fe/Ti ratio of 5.3 and is defined in the present invention.
Since the Fe/Ti ratio deviates greatly from the ratio (1.4 to 2.8), the strength of the annealed material is significantly reduced. (2) Heat resistance: The semi-softening temperature of the alloy of the present invention is 550°C or higher, whereas that of comparative alloys No. 8 and 9 is much lower, at 480°C and 380°C, respectively. In addition, comparative alloys No. 6 and 7 of the Cu-Fe-Ti system showed a remarkable decrease in strength during annealing, and the semi-softening temperature was 520℃, respectively.
The temperature is 480℃. (3) : Thermoelectric conductivity: Since the alloy of the present invention utilizes the precipitation of Fe and Ti, the electrical conductivity is significantly improved by annealing, but the electrical conductivity decreases as the amount of Sn added increases. . However, the invention alloy No. 5 containing 1.54% Sn is comparative alloy No. 9 (phosphor bronze).
, indicating good conductivity.
The annealed materials of alloys No. 1 and 2 of the present invention containing 0.15% and 0.14% of Ti and 0.21% and 0.22% of Sn, respectively, have properties equivalent to or better than the processed material of comparative alloy No. 8 (CDA194 alloy). are doing. (4) Repeated bendability: The number of repeated bendings of the alloy of the present invention is improved by 1 to 4 times compared to comparative alloys No. 6 and 7 that do not contain Sn. The solderability of the alloys of the present invention (Nos. 1 to 7) was determined by applying the alloys of the present invention to a solder bath (Sn60-
I immersed it in Pb40) for 5 seconds and observed the solder adhesion, but no problems were found. I also performed Ag plating on the same sample, but there were no problems at all. As described above, the alloy of the present invention has improved high strength, heat resistance, and repeated bendability, and
Because it has good electrical conductivity and no problems with solderability, it can be widely used in semiconductor lead materials and electrical parts such as connectors and switches, greatly contributing to higher performance, smaller size, and thinner parts. be.

[Brief explanation of drawings]

The attached drawing shows the Cu-Fe-Ti ternary alloy.
It is a graph showing the relationship between the Fe/Ti weight ratio and the electrical conductivity and strength after aging precipitation treatment.

Claims (1)

[Claims] 1 0.1 to 1% by weight of Fe, 0.05 to 0.5% by weight of Ti,
and contains Sn in an amount of more than 0.5% by weight and up to 2% by weight,
The remainder is essentially Cu, and the weight ratio of Fe and Ti is Fe/
A copper alloy for conductive members that has Ti of 1.4 to 2.8 and has excellent conductivity, strength, heat resistance, and repeated bendability. 2 0.1-1% by weight of Fe, 0.05-0.5% by weight of Ti,
More than 0.5% by weight and up to 2% by weight of Sn, and 0.005~
Contains 0.2% by weight of Mg, the balance is substantially Cu, and the weight ratio of Fe and Ti is 1.4 to 2.8.It has excellent conductivity, strength, heat resistance, and repeated bendability. Copper alloy for excellent conductive parts.