JPH04202728A - Copper alloy for electronic equipment - Google Patents

Abstract

PURPOSE:To obtain a copper allay for electronic equipment excellent in peeling resistance of soldering without deteriorating its solderability and having high strength and high electrical conductivity by incorporating a Cu-Ni-P-Si series alloy with Ag, Ti or the like independently or compositely together with Zn and Mn. CONSTITUTION:This is a Cu allay contg., by weight, 1.0 to 8.0% Ni, 0.1 to 0.8% P and 0.06 to 1.0% Si and furthermore contg. one or two kinds of 0.05 to 0.3% Ag and 0.02 to 0.5% Ti. Or, this is a Cu allay obtd. by adding 0.1 to 1.0% Zn to the alloy having the above compsn. so that the total content with Ag or Ti or with Ag+Ti will be regulated to 0.15 to 1.0%. Or, this is a Cu allay obtd. by incorporating specified amounts of one or two kinds of Ag and Zn as well as Mn into the Cu allay contg. the above amounts of Ni, P and Si, or incorporating specified amounts of Ti and Mn or compositely adding Ti, Mn and Zn so that their total content will be regulated to specified one, and it is suitable for electronic equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copper alloy for electronic devices such as lead frame materials and connector materials used in semiconductor devices such as ICs.

[Conventional technology]

Materials used in electronic devices such as VTRs, TVs, and personal computers are becoming increasingly multifunctional and smaller, and demands for higher reliability are increasing. In line with this, in the case of IC lead frame materials, in addition to the main properties of high strength and high thermal conductivity, as ICs become more highly integrated, there is a need for materials with superior corrosion resistance and heat resistance as properties related to material reliability. It is being More IC.

With the progress of high-density mounting of components such as capacitors on circuit boards, the mounting method of IC packages is rapidly changing from pin insertion method to surface mount method (SMT). Excellent heat-resistant peelability of the solder plating applied to the external lead (pin) portion has recently become one of the most important characteristics in terms of reliability. In detail, this means that the solder plating has excellent peeling resistance against temperatures up to around 150°C, which can rise during IC operation; that is, the adhesion between the base metal leads and the solder plating, and the resistance to temperature rise. This also means that it needs to be kept for a very long time.

On the other hand, with regard to connectors, materials are becoming thinner, and the amount of heat generated is also increasing due to an increase in the amount of current applied.

For this reason, materials with better strength, splash characteristics, and electrical conductivity are being sought. In the case of connectors as well, in practical use, the metal terminals are often plated with solder and then soldered, and as with lead frames, the heat-removability of the solder plating against a temperature rise of around 150°C remains to be seen over a long period of time. It is required to be excellent.

As materials for lead frames, Fe-42%N
Copper alloys, which have excellent thermal conductivity (heat dissipation), are increasingly being used in place of i-alloys.

Cu-Fe type copper alloy for lead frames.

Cu-Sn system, Cu-5n-Ni system, Cu-Ni-5
Many types of alloys, such as the i-series, are in practical use.

In addition, phosphor bronze (Cu-4 to Cu-8) is used as a copper alloy for connectors.
%5n-P), Cu-Be alloy (Be 1.8-2
．． 0%).

Cu-Ni-5n alloy (Cu-9%Ni-6%Sn,
Cu-9%Ni-2,3%Sn), etc. are used.

For such copper alloys for electronic devices, in order to provide high reliability to the devices, it is necessary to have excellent heat peeling resistance of the solder plating. There are few excellent alloys, and improvements in this property are desired.

Adding Zn to copper alloys to improve the heat-removability of solder iron plating
It has been disclosed in various patent applications that the addition of is effective. For example, Cu-N shown in Japanese Patent Application No. 63-103206 and Japanese Patent Application No. 63-167330
It is stated that the addition of an appropriate amount of Zn to i-P-3i-Zn series alloys significantly improved the heat peeling resistance of solder plating.

[Problem that the invention attempts to solve]

However, in the copper alloy shown in the above patent application, if the amount of Zn added is in a small range as in Japanese Patent Application No. 63-103206, the effect of improving the heat-resistant peeling property of iron plating is insufficient. Yes, -10,000, patent application 1986-16733
If the amount of Zn added is too large as in No. 0, the soldering strength when joining the solder-plated external leads of the lead frame to the circuit board will decrease, and the alloy containing a relatively large amount of Zn will deteriorate. The disadvantage of this was that stress corrosion resistance deteriorated.

The present invention was made to solve the above-mentioned problems, and it is a high-strength, high-conductivity film that significantly improves the heat-resistant peelability of solder plating without reducing soldering properties. The purpose is to provide copper alloys for electronic devices.

[Means for solving problems]

The alloy of the present invention has (1) Ni1.0 to 80% by weight;
%, 201~08%, Si0.06~1.0%, and further contains Ag0.05~03% and Ti0.02~05%.
Copper alloy for electronic devices containing one or two of the above, with the remainder consisting of Cu and unavoidable impurities, (2) Each of the alloys in (1) above further contains 0.1 to 10% by weight of Zn. Seshime, Ag or Ti or A g + T
Copper alloy for electronic devices in which the sum of i and Zn is in the range of 0.15 to 10% by weight, (3) Ni 1.0 to 8.0 in weight%
%, P0.1-0.8%, 5i006-10%, and further contains Ag 0.05-0.3% and Zn01-10%.
It contains one or two of the above and 0.05-05% of Mn, and if it contains Zn, it is Zn + Mn or Ag + Z.
A copper alloy for electronic devices in which the amount of n+Mn is in the range of 0.2 to 1.0%, and the balance is Cu and unavoidable impurities.
4) Ni 1.0-8.0% by weight.

Contains 11-0.8% PO, 0.06-1.0% Si, and 002-05% Ti, and 0.05-0.05% Mn.
Copper alloy for electronic devices containing 5 F and the remainder consisting of Cu and unavoidable impurities, (5) Zn in the alloy of (4) above.
Contains 0.1 to 1.0% by weight, Ti+Mn+Z
This is a copper alloy for electronic devices in which the amount of n is in the range of 0.17 to 1.0% by weight.

The content of the present invention will be described more simply as follows.

Cu shown in the specification of Japanese Patent Application No. 103206/1983
Each alloy has one or both of Ag and Ti added to the Ni-P-5i alloy for the purpose of improving the heat peeling resistance of solder plating.

In addition, one or two of Ag, Ti, and Mn can be substituted with Zn.
These are alloys in which Mn and one of Ag and Ti are added.

[For production]

In the alloy of the present invention, (1) Ag as an additive element.

Ti alone or in coexistence, ■ coexistence of each of Ag, Ti, and Mn and Zn, ■ coexistence of two elements of Ag, T, and Mn, ■ or Ag, Ti, Mn (7)
Due to the coexistence of our two elements and Zn, the above Cu-N1-P-
It significantly improves the heat peelability of solder plating without impairing the excellent characteristics of high strength and high conductivity inherent to Si alloys. Furthermore, with the present invention, patent application No. 167330/1983
No deterioration in soldering properties occurs due to the addition of a large amount of Zn, which was a problem in the Cu-N1-PSI-Zn alloy shown in the specification of No.

Next, the reasons for limiting the additive components in the copper alloy of the present invention will be explained. The contents of Ni, P, and Si, which are the main components of the alloy of the present invention before the improvement, are determined according to patent application FFB63-
This is the same as No. 103206, and it is a component for imparting excellent gluing strength and conductivity, but since there are no components that characterize the present invention regarding the addition of Ag, Ti, etc., the reasons for limiting these components will be explained here. I won't mention it, but patent application 1986-1032
Same as No. 06.

Ag and Ti are elements that improve the heat peeling resistance of solder plating of Cu-Ni-P-Si alloys, but when each is added alone, the improvement effect is poor below the lower limit, and when the upper limit is exceeded, the conductivity decreases. Since the rate and soldering lead to a decrease in quality,
Ag is 0.05% to 0.03%, Ti is 0.02 to 0.5% (each weight %). Note that Ag is an expensive element, and adding more than 0.3% is not appropriate since the price of the copper alloy will increase too much. Furthermore, the limits when Ag and 11 are added in combination are the same as when they are added alone. Also A
The amount of Mn added in this case is: If it is less than 0.05%, the improvement effect is poor, and if it exceeds 0.5%, the conductivity decreases to a non-negligible extent, so these were set as the limits. Z as a coexisting component
If n is less than 0.1%, the improvement effect will be poor when coexisting with Mn alone, and one of Ag, Ti, or Ag.

Two of Ti and Mn and the amount of Zn (when combined, Z
It is necessary to compensate for the decrease in the effect of improving plating heat resistance due to a small amount of n by increasing the amount of components other than Zn, such as Ag, but an increase in Ag will lead to an increase in material cost, and an increase in T] or Mn. Although this is not a problem in practice, it lowers the electrical conductivity, and in particular, an increase in Ti also lowers the fluidity of the molten metal during melting. Also, the amount of Zn is 1%
If this value is exceeded, the soldering properties and stress corrosion resistance will deteriorate.

Therefore, Zn was set at 01 to 10%.

When one or two of Ag, Ti, and Mn are added in combination with 4Zn, the limits and reasons for the limitations of Ag and Ti are as follows:
, is the same as when Ti is added alone.

In the case of composite addition, in the case of a composite of one or two of Ag, Ti, Mn OD and Zn, the upper limit of their total amount depends on the solder properties, electrical conductivity, or stress resistance. The corrosion resistance was set at 10% to avoid deterioration. Also Z
The lower limit of the total f of n and other components is determined to be 0.15 to 0.2% depending on the selection of additive components, since if it is less than this, the effect of improving the heat-resistant peeling property of plating is poor.

[Embodiments of the invention]

Examples of the present invention will be described below.

Alloys of various compositions were melted in a high-frequency electric furnace, and after side processing, cold rolling and heat treatment were repeated, and a final 37% cold working was performed to produce a plate with a thickness of 0.25 threads. .

The heat treatment before the final finish rolling was performed by heating at 80° C. for 30 minutes, quenching in water, and then aging at 450° C. for 2 hours.

Table 1 shows examples of various properties of the present invention material and comparative material.

All properties are based on the final 37% cold worked thickness of 0.
The measurements were taken on a 25+m plate. In the heat-resistant peelability test of solder plating, first, as a pretreatment, a strip-shaped specimen was degreased, then immersed in a 5vol 1% aqueous hydrochloric acid solution, washed with water, and then neutralized with a 1vol 1% ammonia aqueous solution. Next, each specimen was immersed in a solder bath (230°C) with a composition of 60% Sn - 40% PB by weight and hot-dip plated.
It was held in a constant temperature bath at 150°C in an atmospheric atmosphere for a specified period of time, and then the solder plated part was bent by 90°.
We observed with a microscope whether the plating peeled off or not, and compared the time it took for the plating to occur. The solder wettability test was conducted using a surface tension measurement method. That is, by dipping the solder plating sample heated at 150°C for 1000 hours into a 230°C solder bath at a constant speed to a depth of 8III11 and holding it for a certain period of time, and measuring the wetting time of the specimen during that time using a meniscograph, The solder wettability was evaluated. In Table 1, wettability was described as good (○ mark) if the wetting time was 2 seconds or less, poor wettability (x mark) if it was 10 seconds or more, and fair wettability (△ mark) if it was 3 to 9 seconds.

As is clear from the results in Table 1, the alloys of the examples of the present invention were prepared by adding appropriate amounts of one or both of Ag, Ti, and Mn together with Zn or without Zn. Lead frame J (solder plating has excellent heat peeling resistance, which is one of the important properties required for materials for any electronic device, and has good solderability (solder wettability) after being heated at 150℃ for a long time. In comparative materials, especially when there is a large amount of Zn fi, the solder wettability deteriorates, which poses a practical problem. However, if the amount of Ag, Ti, or Mn added is too large, it causes a decrease in electrical conductivity. This is understandable, and it is not desirable as a material for electronic devices.

〔Effect of the invention〕

As described above, according to the present invention, N I + P + S
Precipitation-hardening alloys in which fine compounds consisting of By combining these additives, the solder plating has excellent heat peeling resistance and soldering properties, as well as high strength and high thermal conductivity.
This has the effect of producing a high-performance, highly reliable copper alloy that is particularly suitable for lead frames of surface-mounted IC packages such as C, and for electronic devices such as connectors.

Claims (5)

[Claims] (1) Ni1.0-8.0%, P0.1-8.0% by weight
0.8%, Si0.06-1.0%, and further A
A copper alloy for electronic devices containing one or two of g0.05-0.3% and Ti0.02-0.5%, with the remainder being Cu and inevitable impurities. (2) Ni1.0-8.0%, P0.1-8.0% by weight
0.8%, Si0.06-1.0%, and further A
One or two of g0.05-0.3% and Ti0.02-0.5% and Zn0.1-1.0%, Ag or Ti or Ag + Ti and Zn total 0.15-0. 1
．． A copper alloy for electronic devices containing Cu in a range of 0%, with the remainder consisting of Cu and unavoidable impurities. (3) Ni1.0-8.0%, P0.1-8.0% by weight
0.8%, Si0.06-1.0%, and further A
Zn and M
A copper alloy for electronic devices, containing n or a total of Ag, Zn, and Mn in a range of 0.2 to 10%, with the remainder being Cu and unavoidable impurities. (4) Ni1.0-8.0%, P0.1-8.0% by weight
0.8%, Si0.06-1.0%, and further T
A copper alloy for electronic devices containing 0.02 to 0.5% i, 0.05 to 0.5% Mn, and the remainder consisting of Cu and unavoidable impurities. (5) Ni1.0-8.0%, P0.1-8.0% by weight
0.8%, Si0.06-1.0%, and further T
i0.02~0.5%, Mn0.05~0.5% and Zn
A copper alloy for electronic devices containing 0.1 to 1.0% in a total range of 0.17 to 1.0%, with the remainder consisting of Cu and unavoidable impurities.