JPH0399792A - Method for soldering or solder-plating ti-containing copper alloy member - Google Patents

Abstract

PURPOSE:To provide soldering method excellent in detaching resistance by using Pb-Sn solder composed of the specific wt.% of Pb + Sn and the specific ppm of impurity elements, in which Ag and O2 are limited to the specific ppms, respectively. CONSTITUTION:A Ti-containing copper alloy member containing 0.01 - 5% Ti, is soldered or solder-plated by using the Pb-Sn solder. Then, the Pb-Sn solder whose component composition is >99.95 wt.%(Pb + Sn) and <= 500 ppm the impurity elements, and particularly limited to < 30 ppm Ag and < 30 ppm O2 with respect to the impurity is used. By this method, reliability of soldering and solder-plating part in electronic or electric parts of the Ti- containing copper alloy member can be improved.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a copper alloy member containing Ti: 0.01 to 5% by weight (hereinafter referred to as Ti) that does not peel off even when exposed to high temperatures for a long time. This relates to soldering or solder plating methods for Ti-containing copper alloy members (referred to as Ti-containing copper alloy members), particularly for soldering or solder plating of Ti-containing copper alloy members used in electronic and electrical components such as lead frames for semiconductor devices, connectors, switches, and sockets. The present invention relates to a soldering or solder plating method that does not cause peeling even when a part is continuously exposed to a high temperature environment for a long time.

[Conventional technology]

Generally, it is known that electronic and electrical parts such as lead frames, connectors, switches, and sockets are made of Ti-containing copper alloy members.For example, lead frames made of Ti-containing copper alloys can be assembled into semiconductor devices. The TI-containing copper alloy lead frame (external lead) incorporated into the semiconductor device is solder plated when mounted (mounted) on a printed circuit board, and then connected (soldered) to the circuit board.

In addition, Ti-containing copper alloy connectors, switches, sockets, and the like are generally plated with solder or soldered for mounting (assembly).

Commercially available Pb-Sn solder has generally been used as the solder for soldering or molten solder plating of electronic and electrical components such as the TI-containing copper alloy lead frames, connectors, switches, and sockets.

[Problem to be solved by the invention]

In recent years, semiconductor devices are often used continuously for long periods of time in high-temperature environments, and as a result, the soldering or solder-plated parts of electronic and electrical components such as lead frames, connectors, switches, and sockets made of TI-containing copper alloys are also becoming more and more difficult. It has become common for people to be exposed to high temperature environments for long periods of time. If the soldered or solder plated parts of these electronic and electrical parts are exposed to a high temperature environment for a long time, the soldered or solder plated parts are likely to peel off frequently. A problem has arisen in that the reliability of the plated portion is significantly reduced, and the reliability of electronic/electrical equipment incorporating the above-mentioned electronic/electrical components is also significantly reduced.

[Means to solve the problem]

Therefore, the present inventors were researching the reason why the soldered or solder plated parts of conventional Tl-containing copper alloy members tend to peel off when exposed to a high temperature environment for a long time, and found that commercially available Pb-Sn solder Among the above impurity elements, especially Ag
It has become clear that o2 and o2 have a negative effect. That is, as a result of the above research, the present inventors have concluded that (1) It is better to have as few impurity elements as possible in the Pb-3n solder, and the content of impurity elements is 500.
ppI is 11 or less, and (2) among the above impurity elements, especially Ag and 02 are each 30 ppm.
Pb- with extremely low content of impurity elements, less than
We found that when Ti-containing copper alloy members are soldered or solder-plated using Sn high-purity solder, peeling does not occur even if the resulting soldered or solder-plated parts are continuously exposed to a high-temperature environment for a long time. I got it.

This invention was made based on this knowledge, and includes a method of soldering or solder plating a copper alloy member containing TI: 0.01 to 5% using pbSn solder, in which Pb +Sn >99.95 A Pb-Sn solder consisting of impurity elements≦500ppm in weight%, in which Ag and 02 are particularly Ag<30ppm among the impurity elements.

02<30ppm.

The present invention is characterized by a method for soldering or solder plating a Tl-containing copper alloy member using a Pb-Sn solder.

In this invention, the reason why the composition range of the Pb-Sn solder used is limited as described above will be explained below.

When the soldered or solder-plated parts of Ti-containing copper alloy members such as lead frames and connectors are exposed to high-temperature environments for long periods of time, Cu in the lead frame and Sn in the solder will diffuse, causing the bond between the T1-containing copper alloy members and the solder to diffuse. C at the interface
In addition to forming a diffusion layer (compound phase) of u and Sn, Ti
Ti, which is an alloy component of the containing copper alloy member, and impurity elements in the solder also diffuse. At this time, the impurity elements in the solder are
If it exists in excess of 00 ppm, it will form an intermetallic compound with T1 in the T1-containing copper alloy member due to diffusion, and peeling will occur easily.
Therefore, the total content of impurity elements is 500p.
Must be below pm. Among the impurity elements contained in the above-mentioned pbSn high-purity solder, Ag in particular has a strong tendency to form a brittle Ti intermetallic compound at the solder interface with the T1-containing copper alloy member, and if a large amount of Ag is included, peeling will occur. It becomes easier. Therefore, Ag is a
Must be kept below oppm.

On the other hand, when oxygen is contained in the Pb-Sn solder, voids are likely to be formed at the interface between the TI-containing copper alloy member and the solder, and these voids continue to cause peeling over time. Therefore, the amount of oxygen contained in the Pb-Sn solder was determined to be less than 30 ppm.

When the brittle Ti intermetallic compound and the void occur simultaneously, the occurrence of peeling of the soldered or solder-plated portion becomes more pronounced.

Therefore, in order to suppress the occurrence of peeling of the soldering or solder plating parts, the content of impurity elements contained in the Pb-8n solder should be reduced to 500 ppm or less, and at the same time, the content of Ag, especially among the above impurity elements, should be reduced to 30 ppm or less.
It is necessary to keep the oxygen content below ppm and below 30 pI)ff1.

〔Example〕

Next, the soldering or solder plating method of the present invention will be specifically explained using examples.

Purity 299.99% by weight Sn, Pb, Ag,
Bi.

Sb and In were prepared, these pure metals were blended, mixed and melted by the method shown in Table 1, and 10 kg of each solder having the component composition shown in Table 1 was melted.

On the other hand, as shown in Table 2, various types of C containing Ti
The u alloy was melted and cast in a high frequency furnace in an Ar atmosphere to obtain an ingot with a vertical dimension of 35 mm, a horizontal dimension of 120 mm, and a length of 200 mm. The ingots of these various Cu alloys were placed face side, and the temperature:
After hot rolling at 850℃ to a thickness of +10mm, it was further face-sided to a plate thickness of 9m+m, and then cold rolling and annealing were repeated at a predetermined temperature within the range of 400 to 600℃. Finally, a strip with a thickness of 20.25 mm was obtained.

Cut this strip into width: 10mm, length + 30mm,
After polishing the surface with #00 emery paper, pickling and degreasing, soldering was carried out using the above solder at a temperature of 230°C using rosin flux.

The sample soldered in this way was soldered at a temperature of 150°C.
The sample was kept in the atmosphere for 250 hours, 500 hours, 750 hours, and 1000 hours, and the cross section of each sample was polished, and the interface between the solder and the Cu alloy strip was observed with an optical microscope to determine if there was any peeling. The presence or absence of the Ol was examined, and those with no peeling were shown in Table 3 with △ indicating that some of the Ol was peeled off, and x indicating that the Ol was completely peeled off.

Furthermore, for comparison, commercially available solder H63A (JIS
Z 3282) and the analysis results are shown in Table 1. Using the commercially available solder mentioned above, strips with the component compositions shown in Table 2 were soldered and subjected to the same treatment to produce commercially available solder. The presence or absence of peeling at the interface between the solder and the Cu alloy strip was also investigated, and the results are also shown in Table 3.

〔Effect of the invention〕

From the results in Table 3, commercially available solder F and Ag: 40p
pm, O,,: Part 2 of the soldered joint obtained by soldering using Pb-Sn solder D containing 50 ppm peeled off after only 250 hours of exposure to the atmosphere at a temperature of 150°C. However, the soldering part using solder A that satisfies the limiting conditions of this invention is at the above temperature: 150°C.
No peeling occurred even after being exposed to the atmosphere for 1000 hours. Therefore, it can be seen that the soldering method of the present invention has an excellent effect on peeling resistance.

Furthermore, pbSn solder B containing Ag in excess of 30 ppm and Pb-Sn solder B containing Ag in excess of soppm
For the soldering part using 8n solder C, the above temperature = 1
When left in the atmosphere at 50°C for 500 hours, some peeling occurred, and parts soldered using solder E with a Pb-t-3n purity of less than 99.95% by weight were left in the high-temperature atmosphere for 750 hours. It can be seen that when exposed for a long time, some peeling occurs and sufficient peeling resistance cannot be obtained.

In addition, in this example, the soldering resistance of Ti-containing copper alloy members obtained by soldering using various Pb-Sn solders was described in detail. When molten solder plating was applied to a TI-containing copper alloy member using -Sn solder, almost the same effect was obtained in terms of peeling resistance of the solder-plated portion.

As mentioned above, in soldering or solder plating of Ti-containing copper alloy members, solder (= Also, it has been found that excellent peeling resistance of the solder-plated part can be obtained, and the reliability of the soldering or solder-plated part of electronic/electrical parts made of such a T1-containing copper alloy part is significantly improved. This product greatly contributes to improving the reliability of electronic and electrical equipment incorporating the electronic and electrical components mentioned above.

Claims (1)

[Claims] (1) In a method of soldering or solder plating a Ti-containing copper alloy member containing 0.01 to 5% Ti using Pb-Sn solder, the Pb-Sn solder has Pb+Sn>99.95% by weight. , impurity elements≦500ppm, and of the above impurity elements, especially Ag and O_
A method for soldering or solder plating a Ti-containing copper alloy member, characterized in that a Pb-Sn solder having a composition in which 2 is Ag<30ppm and O_2<30ppm is used.