JPH11256256A - Copper alloy for electric and electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stamping workability (wear of a stamping die and punching work) while maintaining good strength, conductivity, stress relaxation resistance, plating property, etc. of a Cu-Ni-Si alloy. Burr and droop reduction in copper alloys) are further improved. SOLUTION: Ni: 0.1 to 4.0 wt%, Si:
0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%
%, S: 0.0001 to 0.005 wt%, Se: 0.00003 to 0.003 wt%, Te:
0.00003 to 0.003 wt%, Sb: 0.000
03-0.003 wt%, Bi: 0.00003-0.
A copper alloy containing one or more elements selected from the group of 003 wt% in total of 0.00003 to 0.005 wt%, and the balance being Cu and unavoidable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength copper alloy having excellent stamping workability, plating properties, and stress relaxation resistance used for electric and electronic parts such as semiconductor lead frames, terminals, connectors, relays, and switches.

[0002]

2. Description of the Related Art In recent years, as electric and electronic parts have become smaller, lighter, and more highly integrated, the lead spacing of lead frames or the pitch between connectors has been reduced in order to reduce the mounting volume. The thickness is reduced. Therefore, with respect to these materials, demands for migration resistance and whisker resistance (suppression of whisker of Sn plating) have become more severe, in addition to demands for higher strength and higher conductivity than ever before. In order to respond to such severe requirements, as a Cu-Ni-Si-based copper alloy, for example, Ni: 0.4 to 4.0 wt% and Si: as defined in JP-A-8-319527. 0.1 ~
1.0 wt%, Zn: 1.0 to 2.0 wt%, Cr:
0.0001-0.01 wt%, Mg: 0.0001-
0.001 wt%, and if necessary, Mn: 0.01
0.1 wt%, Al: 0.0001-0.01 wt%
Has been proposed.

[0003] Lead frames and terminals are usually manufactured from a copper alloy material by stamping. In stamping, as the number of times of punching increases, the die wears, and burrs, drooling, etc. occur on the punched product. If they exceed the allowable limits, the dimensional accuracy and residual stress of the product will exceed the standard values, so it is necessary to stop the operation and grind the mold. In this way, from the viewpoint of productivity and yield, the copper alloy used for the lead frame and the terminal, besides the above-mentioned characteristics, also does not wear the mold, and generates burrs, whopping, etc. when stamping is performed. Has been strongly required to be as small as possible. Even in the above copper alloy, it can not be said that the stamping process is sufficient,
Further improvement is required.

[0004]

SUMMARY OF THE INVENTION The present invention relates to the aforementioned Cu-
Stamping workability (reduction of burrs and droop in stamped die and stamped copper alloy) while maintaining good strength, conductivity, stress relaxation resistance, plating property, etc. of Ni-Si alloy. This was done to improve it.

[0005]

The copper alloy for electric / electronic parts according to the present invention comprises: Ni: 0.1 to 4.0 wt%;
0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%
%, S: 0.005 wt% or less, Se: 0.0
03 wt% or less, Te: 0.003 wt% or less, Sb:
0.005 wt% or less of one or more elements selected from the group of 0.003 wt% or less and Bi: 0.003 wt% or less.
t% or less, with the balance being Cu and unavoidable impurities. S is in the range of 0.0001 to 0.005 wt%, and Se is Se: 0.00003 to 0.003 for Se, Te, Sb, and Bi (these are referred to as group A elements).
wt%, Te: 0.00003-0.003wt%, S
b: 0.00003 to 0.003 wt%, Bi: 0.0
Within the range of 0003 to 0.003 wt%, one or more of these are used in a total of 0.00003 to 0.005 wt%.
%.

[0006] The copper alloy for electric / electronic parts further includes:
Pb: 0.0001 to 0.05 wt%, C: 0.00
One or two elements selected from the group of 01 to 0.01 wt% (referred to as element B) are 0.0001 to 0.05 in total.
wt%, P: 0.0001 to 0.1 wt%, Al:
One or two selected from the group of 0.0005 to 0.3 wt% (referred to as group C element) is 0.0001 to 0.3 in total.
wt%, Mg: 0.001 to 1.5 wt%, Mn:
0.001 to 0.5 wt%, Fe: 0.001 to 0.0
Less than 3 wt%, Co: 0.001-0.1 wt%, A
g: 0.0003-0.1 wt%, Cr: 0.0005
To 0.01 wt%, Zr: 0.0005 to 0.01 wt%
%, Ti: one or more selected from the group of 0.0005 to 0.01 wt% (referred to as group D elements).
0003 to 0.7 wt% of BD, Mg and Mg alone or in an appropriate combination thereof can be contained.

It is desirable that the copper alloy for electric and electronic parts has an oxygen content of 30 ppm or less and a hydrogen content of 10 ppm or less. Further, the copper alloy for electric / electronic parts can further contain Sn: 0.01 to 8.0 wt%.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reasons for limiting the components of the copper alloy according to the present invention will be described below. (Ni) By adding Ni together with Si, Ni
-Generates a Si compound and has the effect of improving strength, heat resistance and stress relaxation resistance. If the content is less than 0.1 wt%, this effect is small, and if the content exceeds 4.0 wt%, hot workability and cold workability deteriorate, which is not preferable. Therefore, the content of Ni is set to 0.1 to 4.0 wt%. (Si) By adding Si together with Ni, Ni
-Generates a Si compound and has the effect of improving strength, heat resistance and stress relaxation resistance. If the content is less than 0.01 wt%, this effect is small, and if the content exceeds 1.0 wt%, the hot workability and the cold workability deteriorate, which is not preferable. Therefore, the content of Si is 0.01 to 1.0 wt.
%.

(Zn) Improvement of migration resistance, S
Suppression of whisker generation of n and Sn alloy plating, improvement of heat peeling resistance of Sn and Sn alloy plating, improvement of migration resistance, reduction of abrasion of stamping die, improvement of adhesion of oxide film, deoxidation effect of molten metal, molten metal Has the effect of dehydrogenation. If the content is less than 0.01 wt%, there is no effect.
If it exceeds 5.0% by weight, the electrical conductivity decreases and the solder wettability deteriorates. Therefore, the content is 0.01-5.0w
t%.

(S) When added to a copper alloy, it has the effect of reducing the abrasion of the press die, and improves the stamping workability, such as reducing the burr and nobody of the stamping material. If the S content is less than 0.0001 wt%, the effect is not sufficient. The effect increases as the S content increases, but if the S content exceeds 0.005 wt%, Ag is increased.
Deterioration of plating property. That is, the amount of the Mg-S compound formed in the alloy increases, and when Ag plating is performed, Ag tends to abnormally precipitate in a protruding manner from the Mg-S compound existing on the alloy surface ( Hereinafter, Ag projections). The Ag projections become a problem when the alloy is used as a lead frame for performing Ag plating, because the reliability of bonding wire bonding and plating adhesion is reduced. Therefore, the S content is 0.0001 to
0.005 wt%.

(Group A elements: Se, Te, Sb, Bi) When these elements are added to a copper alloy even in a very small amount, they have a function of reducing the wear of a press die by a lubricating action, and a stamping material. Improve stamping workability by reducing burrs and nobody. Therefore, the life of the press die (the number of punches before re-polishing) is improved, the dimensional accuracy and flatness of the stamped lead frame, terminals and other electrical and electronic components are improved, and the finer spacing between the leads is achieved. Is possible.

The above-mentioned effect increases as the total content of Se, Te, Sb and Bi increases, but the content of any one of them exceeds 0.003 wt% or the total content thereof is 0.005 wt%. %, The alloy contains A
g When plating (matte, semi-gloss, luster) is performed, compounds of these elements, or these elements and S, Cu,
Al, Ag, Co, Cr, Fe, Ni, Sn, Pb, Z
Abnormal precipitation of Ag plating occurs in a portion where a single compound or a complex compound with n, O, or the like is present, and is observed as abnormal gloss or uneven gloss. Further, ingot casting cracks are likely to occur during casting, ingot heating, or hot rolling. Therefore, the content of these elements is as follows: Se: 0.003 wt% or less;
e: at least one element selected from the group consisting of 0.003 wt% or less, Sb: 0.003 wt% or less, and Bi: 0.003 wt% or less must be 0.005 wt% or less. Although these elements have the above-mentioned effects even in a very small amount, Se: 0.00003 to 0.003 wt%, T
e: 0.00003 to 0.003 wt%, Sb: 0.0
0003-0.003 wt%, Bi: 0.00003-
It is desirable that the total content of one or more selected from the group of 0.003 wt% is 0.00003 to 0.005 wt%.

When the relationship between the above-mentioned compound particles present on the surface of the alloy sheet material and the condition of occurrence of the abnormal gloss of the Ag plating was examined, 1000 particles / mm ² of the above-mentioned particles having a size of 0.1 μm or more were found to be 1000 / mm ² . Above this, it was found that the gloss abnormality of the Ag plating is likely to occur. Therefore, the number of the compound particles existing on the plate surface is 0.1
mm ² or less.

(Group B elements: Pb, C)
Each of them has the effect of improving the stamping workability of the present alloy (reducing burrs and drool of the stamping work material and reducing wear of the stamping die). When both Pb and C are less than 0.0001 wt%, the above-mentioned effects are not sufficient. Further, Pb: more than 0.05 wt% or C: 0.
If it exceeds 01 wt%, or if the total content of these exceeds 0.05 wt%, cracks in the ingot during casting or ingot heating are likely to occur, and the hot workability is reduced.
Therefore, Pb: 0.0001 to 0.05 wt%, C:
One or two of the elements selected from the group of 0.0001 to 0.01 wt% are set to 0.0001 to 0.05 wt% in total.

(Group C elements: P, Al) These elements are
When any of these is added to the molten alloy of the present invention, it exhibits a deoxidizing effect, prevents the oxidation of Mg during melting and casting, and has the effect of improving the internal quality and surface quality of the ingot. P: 0.0001wt
% And Al: less than 0.0005 wt%, the above-mentioned effects are not sufficient. Further, if any of these elements exceeds P: 0.1 wt% and Al exceeds 0.3 wt%,
Alternatively, when the total of one or two of these exceeds 0.3 wt%, the electrical conductivity decreases, and the heat-peeling resistance of Sn and Sn alloy plating decreases. Therefore, P: 0.0001-
0.1 wt%, Al: One or two selected from the group of 0.0005 to 0.3 wt% in total of 0.0001 to 0.
3 wt%.

When added to the (Mg) copper alloy, the strength can be improved without significantly lowering the conductivity. In addition, improvement of migration resistance, improvement of spring limit value, improvement of response force relaxation rate, improvement of stamping workability (less burr of stamping material, less drooping, reduction of stamping die wear), deoxidation effect of molten metal Etc. In addition, S in the molten metal is fixed as a Mg-S compound to improve hot workability. If the content is less than 0.001% by weight, the effect is not obtained. If the content exceeds 1.5% by weight, the soundness of the ingot is lowered due to an increase in the viscosity of the molten metal, and grain boundary cracking during hot rolling tends to occur. In addition, work hardening becomes large, and problems such as cracking of ears at the time of cold rolling and deterioration of bending workability occur. Therefore, the content is limited to 0.001 to 1.5 wt%. Mg forms a compound with S and affects not only the stamping workability but also the silver plating property. From the standpoint of stamping workability, it is desirable that Mg and S are large, but the Mg-S compound present in the copper alloy increases, and the portion of the Mg-S compound present on the plate surface when silver plating is performed. Local precipitation of Ag occurs, and Ag projections are formed. To prevent this phenomenon, the M
It is good to increase the amount of Mg, and the Mg content of the alloy (wt%)
Is [Mg] and the S content (wt%) is [S],
It is desirable to make the content satisfy the following formula.
0.25 [Mg] ≧ [S]

(Group D elements: Mn, Fe, Co, Ag, C
(r, Zr, Ti) All of these elements improve the strength, mitigation properties and heat resistance of the alloy. Each of these elements contains Mn: less than 0.001 wt%, Fe: 0.
Less than 001 wt%, Co: less than 0.001 wt%, A
g: less than 0.0003 wt%, Cr: 0.0005 wt%
%, Zr: less than 0.0005 wt%, Ti: 0.0
If the content is less than 005 wt% or the total of one or more of these is less than 0.0003 wt%, the effect is not sufficient. Further, when any of these elements has Mn: 0.
Exceeding 5 wt%, Fe: 0.03 wt% or more, Co: 0.
1% by weight, Ag: 0.1% by weight, Cr: 0.0
Exceeding 1 wt%, Zr: exceeding 0.01 wt%, Ti: 0.
If it exceeds 01 wt%, or if the sum of one or more of these exceeds 0.7 wt%, the ductility and conductivity of the material decrease. Therefore, Mn: 0.001 to 0.5 w
t%, Fe: 0.001 to less than 0.03 wt%, C
o: 0.001-0.1 wt%, Ag: 0.0003-
0.1 wt%, Cr: 0.0005 to 0.01 wt%,
Zr: 0.0005 to 0.01 wt%, Ti: 0.00
One or more selected from the group of 05 to 0.01 wt% is 0.0003 to 0.7 wt% in total. In addition,
This alloy contains Si as an essential element, and when P is added from the C group element, silicide and / or phosphide of the D group element is formed depending on the working heat treatment conditions, and the strength, heat resistance,
It further contributes to the improvement of the response relaxation characteristics and the conductivity.

(Oxygen) The copper alloy has an oxygen content of 30 p
If it exceeds pm, a decrease in solderability and a decrease in plating property will occur, and the heat and peeling resistance of solder and plating will also decrease. In addition, since oxides increase in the alloy, phenomena such as cracking of the cold-rolled material and a decrease in bending workability occur due to a decrease in ductility during cold working, and the press punching property is reduced.
Therefore, the content is set to 30 ppm or less. In the present alloy, a desirable range of the oxygen content is 20 ppm or less,
A more desirable range is 15 ppm or less. The oxygen content in the present alloy is defined as the total amount of oxygen and copper and / or oxides of additional elements present as a solid solution in the alloy.

(Hydrogen) The alloy has a hydrogen content of 10 ppm
Is exceeded, hot workability is deteriorated, and swelling or the like is likely to occur due to heating after performing Ag plating, Ni plating, or the like, and it is difficult to use the resultant as an intended electric or electronic component. Therefore, the content is set to 10 ppm or less. In the present alloy, a desirable range of the hydrogen content is 5 ppm or less, and a more desirable range is 3 ppm or less. In addition,
The content of oxygen and hydrogen in the alloy can be kept in the range of [H] ² [O] = 3 to 100 in the product thin plate by sufficiently drying the raw materials and controlling the atmosphere in the melting and casting process ( [H]: amount of hydrogen (ppm) contained in the alloy, [O]: amount of oxygen contained in the alloy (pp
m)).

(Sn) Solid solution in Cu matrix or M
g to form a compound to further improve the strength and spring limit value of the present alloy containing Mg. If the content is less than 0.01 wt%, the effect is small, and if it exceeds 8.0 wt%, hot working becomes difficult and the decrease in conductivity becomes large. Therefore, Sn
Is 0.01 to 8.0 wt%.

The copper alloy according to the present invention can be produced by a process of hot rolling an ingot formed by continuous casting, and then combining cold rolling and heat treatment to a predetermined thickness. In addition to this, it is possible to obtain a predetermined thickness by performing heat treatment and cold rolling on an ingot having a thickness of 5 to 30 mm formed by horizontal continuous casting without using hot rolling.

The copper alloy according to the present invention is excellent in both hot rollability and cold rollability, and does not cause problems such as cracks in each step, and particularly during the process such as scalping of hot rolled material. Even in the case of cutting, the cutability is very excellent, so that the blade of the scalper is hardly worn or seizure is less likely to occur on the surface. Further, since the copper alloy of the present invention is strengthened by precipitating a Ni—Si compound in the matrix, a solution treatment and an aging treatment are required. The solution treatment can be performed by a method of quenching the hot-rolled material immediately after the end of hot-rolling by water cooling, and / or a method of rapidly cooling the cold-rolled material after passing it through a continuous heating furnace at a predetermined temperature. As the precipitation treatment, it is desirable to use a batch-type heating furnace in order to sufficiently precipitate Ni and Si dissolved by the solution treatment, but when the addition amount of Ni and Si is small or the precipitation amount is small. If there is no problem, a continuous heat treatment furnace may be used. The conditions of the solution treatment and the aging treatment are determined in consideration of the contents of Ni and Si, target mechanical properties, electrical conductivity, crystal grain size, etc. When a continuous heat treatment furnace is used from a temperature of 600 ° C. or more, it is desirable that the ambient temperature be 650 ° C. or more. The aging treatment conditions for the copper alloy of the present invention are as follows.
６００600 ° C. and a holding time of 5６００600 minutes may be employed.

The alloy of the present invention may be subjected to aging treatment or cold rolling after cold rolling, or may be subjected to a heat treatment for the purpose of recovering ductility, improving strain, and improving a spring limit value. You may. The processing rate in the case of cold rolling is suitably 3 to 80% in terms of the reduction rate of the sheet thickness. When heat treatment is performed after the final cold rolling, either a batch method or a continuous method may be used. When using a batch heating furnace,
200 to 500 ° C x 5 minutes to 5 hours hold (material arrival temperature x
Holding time after arrival), 300 ~ when using a continuous annealing furnace
The objective can be achieved under the condition of 800 ° C. × 10 to 300 seconds holding (material arrival temperature × holding time after arrival). After the cold rolling, a process such as tension leveling and tension annealing may be applied, or after the cold rolling and annealing, a process such as tension leveling and tension annealing may be further applied to correct the distortion.

As described above, in the case of using the material in either cold rolling or heat treatment, the crystal grain size in the sheet thickness direction in the cross section of the thin sheet parallel to the rolling direction may be 20 μm or less. In a cross section parallel to the rolling direction with an increase in the rolling rate, the crystal grains become flat in the thickness direction and eventually have a fibrous structure. The particle size may be 20 μm or less. If the crystal grain size exceeds 20 μm, the occurrence of burrs during stamping will increase. Also,
During bending after stamping, a rough surface called orange peel and a crack due to the rough surface are easily generated in a bent portion. Further, the strength is also reduced. Therefore, the crystal grain size of the alloy is desirably 20 μm or less. Burr during stamping, rough surface during bending,
From the viewpoint of cracking and strength of the bent part, the crystal grain size is 15 μm
The following is more desirable, and still more desirably 10 μm or less. When the crystal grain size is in the above range, the copper alloy of the present invention has good etching workability and can be used as a lead frame material for etching.

The lead frame used for this alloy is S
i-chip mounting-200 to 200 in packaging process
Heated to 350 ° C. In the wire bonding process, heating is usually performed in a non-oxidizing atmosphere such as a nitrogen-hydrogen mixed gas in order to prevent oxidation during heating, but it is difficult to completely prevent air from entering the heating furnace. For,
In addition, when the line stops due to an unexpected situation, the time for staying in the furnace is prolonged, so that it is oxidized by the invading atmosphere. If the adhesion strength between the oxide film formed on the surface of the lead frame and the base material is low, moisture enters through gaps generated by the oxide film peeling off from the base material after resin molding, and significantly lowers the reliability of the IC. . Therefore, when used for a lead frame, adhesion of an oxide film is an important required characteristic. The surface roughness of the alloy is such that the center line average roughness (Ra) exceeds 0.2 μm or the maximum height (R
When (max) exceeds 1.0 μm, the adhesion of the oxide film is reduced. From this point, the surface roughness is desirably Ra: 0.2 μm or less and Rmax: 1.0 μm or less. And, when this condition is satisfied in the surface roughness, there is no problem in plating property, bending workability, etc.
It is suitable for electric and electronic parts such as lead frames, terminals and connectors.

Further, in the alloy of the present invention, B, Ca, Sc, V, Ge, As, S
r, Y, Nb, Mo, Rh, Pd, Cd, In, a rare earth element, Hf, Ta, W, Re, Os, Pt, Au, etc .;
1wt% ~ 0.1wt%, total 0.0001 ~ 0.3w
If it is up to t%, it may be contained in order to improve heat resistance, response relaxation characteristics and corrosion resistance without significantly lowering conductivity, stamping workability, plating property and the like.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the copper alloy for electric / electronic parts according to the present invention will be described. (Example 1) <Preparation of Sample> No. 1 shown in Tables 1 to 4 while covering charcoal in the air. An alloy having a composition of 1 to 24 was melted in a kryptor furnace, cast into a book mold, and was 50 mm thick and 9 mm wide.
An ingot having a length of 0 mm and a length of 200 mm was produced. Further, in order to prevent intrusion of hydrogen into the molten metal, measures such as drying of raw materials, fluxes, molds, jigs, and the like, and red heat of charcoal were taken (except for No. 23).

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

This ingot was heated to 930 ° C. for 1 hour, hot-rolled to a thickness of 15 mm, hot-rolled at 750 ° C. or higher, and cooled with water. In addition, when the Mg content exceeds 1.5%
o. No. 18 alloy having a Sn content exceeding 8%. No. 19 alloy and No. Since there was a risk of hot rolling cracking, Alloy 21 was heated at 700 ° C. for 1 hour for homogenization, then heated to 750 to 850 ° C., and hot rolled.
No. 16, No. 19 and no. The alloy No. 21 cracked during hot rolling, and it was thought that subsequent cold rolling was impossible in a state of a thickness of 15 mm, so the subsequent steps were not applied.
In addition, No. In the case of Alloy 23, slight edge cracks occurred at the end face during hot rolling, but the edge cracks were removed and the subsequent process was applied.

The hot-rolled material was mechanically removed of oxide scale on the surface and cold-rolled to 0.357 mmt. However,
No. In No. 18, rolling was stopped because ear cracks became severe during cold rolling, and the subsequent steps were not applied. Then, after heating to 650-850 degreeC for 20 seconds for solution, it rapidly cooled in water. Furthermore, after the surface oxide film was removed by pickling, cold rolling was performed at a thickness reduction rate of 30% to a plate thickness of 0.25 mm, and heat treatment was performed at 440 to 500 ° C. for 2 hours. The material after the heat treatment was subjected to a test by removing the oxide film on the surface by pickling. Hereinafter, a method of analyzing alloy elements and the like and a method of testing alloy characteristics performed in this example will be described.

<Analysis of Alloy Element Content and Gas Amount> [Alloy element] A sample was collected from a thin plate, sufficiently degreased, and subjected to a method (Zn, Mn, Ni,
Fe, Co, Cr, P, Si, Al, Se, Te, P
b, As), ICP-MS, GD-MS, atomic absorption method and the like. In addition, each element was analyzed twice, and the average value was defined as the content. [Gas] A sample was collected from a thin plate, and electropolished in hydrochloric acid to sufficiently remove an oxide film on the surface, and then analyzed. Among them, oxygen was measured by a method (inert gas melting infrared absorption method) specified in JIS-H1067. In this method, measurement is performed by heating the oxide to the temperature at which it also melts.
The measured amount of oxygen is the sum of oxygen dissolved in the copper alloy and oxygen forming an oxide with copper and / or other elements. Each sample was measured three times, and the average value was used as the measured value. Hydrogen was measured by the method specified in JIS-Z2614. Each sample was measured three times, and the average value was used as the measured value.

<Test Method> [Mechanical Properties] A JIS No. 5 test piece with the longitudinal direction parallel to the rolling direction was processed, and the tensile strength and elongation were measured. The number of test pieces was three for each sample, and the average of the measured values was used as the measurement result. [Electrical conductivity] Based on the method specified in JIS H0505, a double bridge 5752 manufactured by Yokogawa Electric Corporation was used for the measurement. Two test pieces were used for each sample, and the average of the measured values was used as the measurement result. [Spring limit value] Based on JIS H3130, the amount of permanent deflection at room temperature was measured by a moment type test, and Kb
0.1 was calculated. The longitudinal direction of the test piece was parallel to the rolling direction. Ten test pieces were used for each sample, and the average of the measured values was used as the measurement result. [Stress relaxation characteristics]

As shown in FIGS. 1 and 2, a test piece 1 having a width of 10 mm was subjected to a cantilever method, and a bending stress of 80% of the proof stress of the test piece was applied to a position having a length (l) of 80 mm. After maintaining at 160 ° C. for 1000 hours with the stress applied, the stress was removed. The deflection (δ: 10 mm) of the test piece at the load point when the stress was applied and the displacement (ε1) when the stress was removed were measured, and the stress relaxation rate was measured by the following equation. Ten test pieces were collected from each sample, and the average of the measured values was used as the measurement result. Stress relaxation rate (%) = (ε1 / δ) × 100 The bending stress (σ) is calculated by the following equation. σ = (3 × E × t × δ) / (2 × l ² ) where σ: bending stress = proof strength of test piece × 0.8 E: Young's modulus of test piece (N / mm ² ) t: test piece Thickness = 0.25mm

[Crystal Grain Size] The crystal grain size is determined according to JIS-H050 in the sheet thickness direction in a section of the sheet parallel to the rolling direction.
Measure by the cutting method specified in 1. 5 specimens from each sample
Each specimen was sampled, and an optical microscope photograph was taken for each specimen in three visual fields (magnification: 100 to 200 times). The photograph was measured by a cutting method, and the average value of 15 data was taken as the crystal grain size. [Heat-Removing Resistance of Sn and Sn Alloy Plating] In the alloy of the present invention, the same result can be obtained regardless of whether Sn plating or Sn alloy plating is performed. Sex was investigated. Width 10
Ten test pieces of 50 mm in length and 50 mm in length were collected from each sample. As the solder plating, a 90Sn / 10Pb solder plating bath (40 ° C.) composed of 193 g / l stannous alkanol sulfonate, 3.5 g / l lead alkanol sulfonate, 100 g / l alkanesulfonic acid, and 30 cc / l additive was used. 90 Sn / 10 Pb solder plating with a plating thickness of 10 μm was applied at a current density of 3 A / dm ² . Thereafter, the plate was heated in a 150 ° C. oven for 1000 hours, bent at 180 ° at 2 mmR, then returned to a flat plate, and visually inspected for the presence or absence of peeling of the solder plating at the bent portion. For the test piece that did not cause peeling, the cross section of the bent portion was polished, and the interface between the plating and the base material was observed with an optical microscope to confirm the presence or absence of microscopic peeling.

[Ag plating property] The width of each sample was 25 mm.
Ten test pieces having a length of 50 mm were sampled, and each test piece was degreased and pickled, and then 1 μm thick using a cyan Ag plating bath.
m was performed. Thereafter, the presence or absence of gloss on the Ag plating surface is visually inspected. If no gloss-generating portion is observed, it is evaluated as ○, and if it is observed, it is evaluated as ×. And
When no swelling was observed, it was evaluated as ○, and when it was observed, it was evaluated as ×. In addition, the surface was observed, and the presence or absence of protrusions was examined. Those having a size of 5 μm or more were counted as protrusions, and one or less per cm ² was evaluated as “good”.

[Compound Particles Containing Se, Te, Sb or Bi] Two 10 mm × 10 mm test pieces were sampled from each sample, and the surface thereof was observed by EDX (magnification: × 100).
0 to 3000), and an EDX spectrum of the particles observed on the surface was obtained, and the number of particles containing one or more of Se, Te, Sb, and Bi and having a diameter exceeding 0.1 μm was determined. . 1mm x 1m for each test piece
m twice, so that for each sample 1 mm x
The area of 1 mm was measured four times, and the average value was used as the measurement result.
Those with 0 / mm ² or less were evaluated as ○, and 1000 / m 2
Those exceeding m ² were evaluated as x. The observation was performed using a JEOL JSM5800LV scanning electron microscope (SEM).
/ EDX) and the acceleration voltage is 15 kV.

<Results> Tables 5 and 6 show the results of the survey for each sample.
Shown in

[0041]

[Table 5]

[0042]

[Table 6]

No. 2 having the composition specified in the present invention. 1 to
No. It can be seen that No. 14 not only excels in strength, electrical conductivity, spring characteristics, etc. required for electrical and electronic components such as lead frames and terminal connectors, but also exhibits excellent characteristics in plating properties, stress relaxation resistance properties, and the like. . On the other hand, no. In No. 15, since the contents of Ni and Mg were below the lower limits of the present invention, the strength was low and projections were formed on the Ag-plated surface. In the case of No. 3 in which the contents of Ni and Si exceed the upper limit of the present invention. In No. 16, cracks occurred during hot rolling, and it was substantially impossible to continue cold rolling further. No. 1 having a Zn content below the lower limit of the present invention. 1
In No. 7, the solder plating peeled off in 500 hours, and the Mg content exceeded the upper limit of the present invention. Sample No. 18 had severe ear cracks during cold rolling, and could not be cold rolled thereafter. S
No. n content exceeding the upper limit of the present invention. No. 19 was not tested because it was difficult to prevent cracking during hot rolling even when the hot rolling temperature and heating time were changed, and it was difficult to manufacture by the hot rolling method.

Group D (Mn, Fe, Co, Ag, Cr, Z
r, Ti) whose content exceeds the upper limit of the present invention.
o. No. 20 is No. In comparison with No. 4, elongation is not enough, and cracking is likely to occur when bending is performed. Also, the conductivity is relatively low. The content of the element of Group C (P, Al) exceeds the upper limit of the present invention. In No. 21, hot rolling cracks occurred, and it was impossible to proceed with the subsequent steps. Group A (Se, T
e, Sb and Bi), the content of elements exceeding the upper limit of the present invention. In No. 22, compounds containing these elements are generated in large amounts, and even when matte Ag plating is performed, uneven gloss is generated (plating becomes glossy at a portion covered with the compound), and application to lead frames and terminals is difficult. . No. 1 having a hydrogen content exceeding the upper limit of the present invention. In No. 23, ear cracks occur during hot rolling, the hot ductility is reduced, and swelling occurs in a heating test after Ag plating, and it is difficult to apply Ag to plating. No. 1 having an oxygen content exceeding the upper limit of the present invention.
No. 24 caused no particular problem in the manufacturing process, but was poor in bending workability due to low elongation. In addition, blistering occurs in a heating test after Ag plating, and it is still difficult to apply the method to an application in which Ag plating is performed.

(Example 2) <Preparation of samples> Alloys having the six compositions shown in Table 7 were melted in a coreless furnace while coating with charcoal in the air, and 150 mm thick and 600 m wide by semi-continuous casting.
m, an ingot having a length of 5000 mm was produced. In the melting casting, the melting furnace and the gutter were sufficiently covered to prevent oxidation of the molten metal and absorption of hydrogen gas.

[0046]

[Table 7]

The ingot was heated to 930 ° C. for 1 hour, hot-rolled to a thickness of 15 mm, and water-cooled from 700 ° C. For the hot-rolled material, the oxide scale on the surface was removed with a scalper, and cold rolling was performed to produce a coil of 0.357 mmt.
These coils were passed through a continuous annealing furnace at 850 ° C. to perform a solution treatment. The sheet was passed at an appropriate speed determined in advance for each composition. After the solution-treated coil was pickled, it was cold-rolled with a thickness reduction rate of 30% to a sheet thickness of 0.25 mm, and heat-treated at 440 to 500 ° C for 2 hours. The material after the heat treatment was subjected to a test by removing the oxide film on the surface by pickling. For the coil of each sample, in the manner of Example 1,
After measuring the tensile strength, elongation, conductivity and crystal grain size,
Stamping was performed in the following manner, and punching workability was investigated. In addition, when the components, the structure, the mechanical properties, and the electrical conductivity were examined in the entire length and width directions of the coil, it was confirmed that there was almost no variation among them.

[Punching workability] The original coil of each sample was slit to a width of 30 mm to form a narrow coil. Using a sample slit near the center in the width direction of the original coil, a lead having a width of 0.5 mm and a length of 20 mm was continuously punched by a press (manufactured by Bruderer). 01 mm, and the number of strokes that required re-polishing of the mold was measured. When the number of strokes exceeded 3 million times, it was evaluated as ○, and when it did not reach 3 million times, it was evaluated as x. The breathing die is made of super steel, the clearance is 0.025 mm on one side (5% of the lead width), and the punching conditions are a punching speed of about 500 shots / min.

<Results> Table 8 shows the inspection results of each sample.

[0050]

[Table 8]

No. 1 having the composition specified in the present invention. 25
-No. No. 28 has excellent punching workability. On the other hand, no. 29 is the Mg and A group (S
Since the content of the elements e, Te, Sb, and Bi) is below the lower limit of the present invention, the punching workability is poor.

(Example 3) <Production of sample> About alloy 27,
When a 0.357 mm cold-rolled material coil was continuously annealed, the sheet passing speed was changed to produce coils having different crystal grain sizes.
They were cold-rolled to 0.25 mmt and heated to 440 to 500 ° C. to perform aging treatment.

<Test Method> The influence of the crystal grain size on the burr height during stamping and the effect of the crystal grain size on the surface roughness during bending were investigated by the following method. [Stamping Burr Height] Using the press used in Example 2, the lead was punched out, and the lead portion at the time when 10,000 samples were punched out of the sample having each crystal grain size (the longitudinal direction of the lead was perpendicular to the rolling direction) The burr height was observed with a scanning electron microscope. The number of observations was 20 per sample, and the average value was defined as the burr height of each sample. [Bend appearance] B type bending jig specified in CESM0002 Metal Material Bending Test Method, width 10 mm, length 35
mm test piece, and a universal tester RH- manufactured by Shimadzu Corporation.
Using the No. 30, a bending process with a bending radius of 0.25 mm was performed under a load of 1 Ton. The test was performed using five samples for each sample so that the bending line was perpendicular to the rolling direction. After that, the outside of the bent part is Olympus Optical S
Using a ZH-type optical stereo microscope, observation was performed at a magnification of 40 times, and the presence or absence of occurrence of skin roughness appearing at several times the crystal grain size was investigated.

<Test Results> The results are shown in Table 9.

[0055]

[Table 9]

No. 1 having a crystal grain size of 20 μm or less. 27
-1 to No. In No. 27-4, the amount of generation of stamping burrs was small, and no rough surface was generated after the bending test, and good stamping properties and bending workability were obtained. On the other hand, No. 1 having a crystal grain size exceeding 20 μm. No. 27-5 and No. 27. 2
In the case of 7-6, the amount of stamping burrs suddenly increases, and the surface roughness after the bending test occurs.

(Example 4) <Preparation of Sample> Twenty-seven samples were used. 25mm from the position 100m from the coil circumference
A × 50 mm test piece was cut out and polished with a cloth having a different roughness to change the surface roughness. The sample whose roughness was adjusted was immersed in acetone, ultrasonically cleaned, and further subjected to electrolytic degreasing to obtain a heated sample. The number of test pieces for each sample was five. Before heating, the surface of the test piece was examined with an X-ray photoelectron analyzer (ESCALAB-210 manufactured by VG).
D) (Mg, Kα, 15 kV, 20 mA), and the initial oxidation state was investigated. The ratio (O1s) / (Cu2p) of the oxygen peak intensity to the copper peak intensity was 0.4 for each test piece.
The initial oxidation state was constant.

<Test Method> The influence of surface roughness on oxide film adhesion was investigated by the following method. [Surface Roughness] The probe was ultrasonically cleaned with acetone, and the probe was scanned over a length of 5 mm in parallel with the rolling direction to measure the roughness. Five specimens of each sample showed almost the same surface roughness. The average value of five data was used as the surface roughness of each sample. For the measurement of the surface roughness, a stylus type surface roughness meter (manufactured by Taylor Hobson) was used. The surface roughness is defined according to JIS-B0601 (definition and display of surface roughness).

[Adhesion of Oxide Film] A hot plate (hot plate HHP-4 manufactured by SEFI) maintained at 300 ° C.
01) and a test piece of each surface roughness was placed thereon and heated for 30 minutes. After elapse of a predetermined time, the mixture was cooled to room temperature, a commercially available acetate adhesive tape (3M No. 810) was stuck, and immediately peeled off, and the presence or absence of an oxide film adhered to the adhesive surface of the tape was visually inspected. ○: No oxide film adhered to the adhesive surface, ×: Small oxide film adhered to the adhesive surface
Was evaluated. The heating and peeling test using a hot plate was performed in a room at 25 ° C. and a relative humidity of 60%.

<Test Results> The results are shown in Table 10.

[0061]

[Table 10]

Surface roughness Ra: 0.2 μm or less, Rma
x: 1.0 μm or less. 27-7 and no. 2
In No. 7-8, the oxide film was not peeled off, but the surface roughness exceeded the above range. 27-9 and no. 27-10
In, the oxide film is exfoliated.

[0063]

The copper alloy according to the present invention satisfies the characteristics required for electric and electronic parts, such as strength, electrical conductivity, and heat-peeling resistance of solder, and has good stamping workability (abrasion of the stamping die is small). The burrs that occur are small, and the plating properties are excellent. Therefore, the present invention greatly contributes to improvement in productivity and reliability of electric / electronic parts.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a method for evaluating stress relaxation characteristics.

FIG. 2 is a side view thereof.

[Explanation of symbols]

 1 Test piece

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Manako 14-1, Chofu Minatocho, Shimonoseki City, Yamaguchi Prefecture Inside of Kobe Steel's Chofu Works (72) Inventor Satoshi Maruo 14-1, Minatomachicho, Shimonoseki City, Yamaguchi Prefecture Shares Kobe Steel Chofu Works

Claims (8)

[Claims] 1. Ni: 0.1 to 4.0 wt%, Si:
0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%
%, S: 0.005 wt% or less, Se: 0.0
03 wt% or less, Te: 0.003 wt% or less, Sb:
One or two or more elements selected from the group of 0.003 wt% or less and Bi: 0.003 wt% or less have a total of 0.0
A copper alloy for electric and electronic parts having excellent stamping workability, containing not more than 05 wt% and the balance being Cu and unavoidable impurities. 2. Ni: 0.1 to 4.0 wt%, Si:
0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%
%, S: 0.0001 to 0.005 wt%,
e: 0.00003 to 0.003 wt%, Te: 0.0
0003-0.003 wt%, Sb: 0.00003-
0.003 wt%, Bi: 0.00003 to 0.003
One or more of the elements selected from the group of wt% are contained in a total of 0.00003 to 0.005 wt%, and the balance is C
A copper alloy for electric and electronic parts having excellent stamping workability, comprising copper and unavoidable impurities. 3. Pb: 0.0001 to 0.05 w
t%, C: one or two elements selected from the group of 0.0001 to 0.01 wt% in total of 0.0001 to 0.0
The copper alloy for electric / electronic parts having excellent stamping workability according to claim 1, wherein the copper alloy contains 5 wt%. 4. P: 0.0001 to 0.1 wt.
%, Al: One or two kinds selected from the group of 0.0005 to 0.3 wt% are contained in a total of 0.0001 to 0.3 wt%. Copper alloy for electrical and electronic parts with excellent stamping workability. 5. Mg: 0.001 to 1.5 wt%
The copper alloy for electric / electronic parts excellent in stamping workability according to any one of claims 1 to 4, characterized by being contained. 6. Mn: 0.001 to 0.5 wt.
%, Fe: 0.001 to less than 0.03 wt%, Co:
0.001-0.1% by weight, Ag: 0.0003-0.
1 wt%, Cr: 0.0005 to 0.01 wt%, Z
r: 0.0005 to 0.01 wt%, Ti: 0.000
The stamping workability according to any one of claims 1 to 5, wherein one or more selected from the group of 5 to 0.01 wt% is contained in a total of 0.0003 to 0.7 wt%. Excellent copper alloy for electric and electronic parts. 7. The copper alloy for electric and electronic parts having excellent stamping workability according to claim 1, further comprising an oxygen content of 30 ppm or less and a hydrogen content of 10 ppm or less. 8. The copper alloy for electric / electronic parts excellent in stamping workability according to claim 1, further comprising Sn: 0.01 to 8.0 wt%.