JPH09302427A - Copper alloy for electronic equipment and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of short circuit between pins of lead frame, etc., and peeling of plating layer and to improve dimensional accuracy and die life at the time of punching. SOLUTION: This copper alloy for electronic equipment is a copper alloy having a composition consisting of, by weight, 0.1-0.4% Cr, 0.05-2.0% Sn, 0.05-2.0% Zn, 0.002-0.2%, in total, of one or more elements among Sr, Ba, and Bi, <0.2% (including 0%) Zr, <0.01% P, <0.005% S, <0.005% O2 , and the balance Cu with inevitable impurities or a copper alloy having a composition consisting of, by weight, 0.1-0.4% Cr, <0.2% Zr, 0.05-2.0% Sn, 0.05-2.0% Zn, 0.002-2.0%, in total, of one or more elements among Sr, Ba, and Bi, <0.01% P, <0.005% S, and <0.005% O2 , and the balance Cu with inevitable impurities. Further, the size of the crystallized substances or precipitates contained in the copper alloy and the crystalline grain size of the copper alloy are regulated to <3μm and <5μm, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy suitable as a lead material, a terminal material, a connector material, a switch material, an electrode material and the like for electric and electronic equipment, and particularly to a lead frame material for semiconductor elements such as ICs. The present invention relates to a suitable copper alloy for electronic devices and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, many semiconductor lead frame materials and terminal materials include copper-based materials such as Cu-Sn system and Cu-Fe system, which are excellent in electric conductivity and thermal conductivity, in addition to iron-based materials. Has been used. By the way, in addition to electrical conductivity and thermal conductivity, the lead frame material and the like are excellent in plating property such as Ag, solder bondability, punching processability or etching processability, surface smoothness, etc. Price is required. Further, these required characteristics are becoming more severe as the recent high density integration and miniaturization of semiconductor devices or high density packaging progress. Particularly in the case of lead frame materials, in recent years, the demand for lead frames with a large number of pins has increased, and as a result, the spacing between pins has tended to become narrower. Therefore, it is desired to improve the precision of punched end faces. There is. Under such a circumstance, Cu-Cr is added to the copper alloy.
System, Cu-Cr-Zr system, Cu-Cr-Sn system and other precipitation hardening copper alloys have come to be used. The precipitation hardening type copper alloy utilizes precipitation of Cr or Zr, and is an alloy in which strength and conductivity are well balanced.

[0003]

However, the precipitation hardening type copper alloy has problems that short circuits easily occur between pins, the dimensional accuracy of the punching material is low, and the life of the punching die is short. there were. Therefore, the inventors of the present invention conducted extensive research into these causes. And, regarding the above, it is caused by needle-like or plate-like precipitates elongated by processing, whiskers grown from the precipitates, minute burrs or powder generated during punching processing, and the above In addition to the precipitation of alloying elements, the inventors have found that the cause is the size of crystal grains, the size of precipitates (crystallized substances), etc., and have further researched to complete the present invention. It is an object of the present invention to provide a copper alloy for electronic devices, which is suitable for lead materials, terminal materials, connector materials, etc., especially multi-pin lead frame materials, and a method for producing the same.

[0004]

According to the first aspect of the present invention,
Cr 0.1-0.4wt%, Sn 0.05-2.0wt%, Zn 0.05
~ 2.0wt%, Sr, Ba, Bi one or more in total 0.002
~ 0.2wt%, Zr less than 0.2wt% (including 0wt%), P
Is less than 0.01 wt%, S is less than 0.005 wt%, O ₂ is less than 0.005 wt%, and the balance is a copper alloy consisting of Cu and inevitable impurities, or Cr is 0.1 to 0.4 wt%, Zr is less than 0.2 wt%, and Sn is less than 0.2 wt%. 0.05
~ 2.0wt%, Zn 0.05-2.0wt%, 1 of Sr, Ba, Bi
A copper alloy containing 0.002 to 0.2 wt% in total, P less than 0.01 wt%, S less than 0.005 wt%, O ₂ less than 0.005 wt%, and the balance Cu and inevitable impurities. The copper alloy for electronic devices is characterized in that the size of crystallized substances or precipitates contained in the alloy is less than 3 μm, and the grain size of the copper alloy is less than 5 μm.

According to the second aspect of the present invention, Cr is contained in an amount of 0.1 to 0.4 w.
t%, 0.05 to 2 wt% Zn, Co, Mg, Mn, Si, Sn
0.01 to 1 wt% in total, and 0.005 to 0.1 wt% in total for one or more Pb and Bi, and P content of 0.
Less than 01 wt%, S and O ₂ contents of less than 0.005 wt%, respectively, and a copper alloy consisting of the balance Cu and unavoidable impurities, or Cr of 0.1 to 0.4 wt%, Zr of less than 0.2 wt%, Zn of 0.05.
~ 2wt%, 0.01 to 1wt% of Co, Mg, Mn, Si and Sn in total, 0.005 to 0.1wt% of Pb and Bi in total and 0.01wt% of P %, S and O ₂ contents are each less than 0.005 wt%, and the balance Cu
And an unavoidable impurity, wherein the size of the crystallized substance or precipitate contained in the copper alloy is less than 3 μm, and the grain size of the copper alloy is less than 5 μm. It is an alloy.

According to the third aspect of the invention, Cr is 0.1 to 0.4w.
t%, 0.05 to 2 wt% Zn, Co, Mg, Mn, Si, Sn
0.01 to 1 wt% in total, and 0.005 to 0.1 wt% in total for Ca, Sr, Ba, and Pb and Bi.
Includes 0.005 to 0.2 wt% of one or more of Te in total (however, Pb
(Excluding the coexistence of Ca and Ca), the content of P is less than 0.01 wt%, S
And the content of O ₂ are each less than 0.005 wt% and the balance C
Copper alloy consisting of u and unavoidable impurities, or Cr of 0.1 to
0.4wt%, Zr less than 0.2wt%, Zn 0.05-2wt%, Co,
0.01 to 1 wt% of one or more of Mg, Mn, Si and Sn in total
In addition, 0.005 to 0.1w in total of one or more of Pb and Bi
0.005 of t%, one or more of Ca, Sr, Ba and Te in total
~ 0.2 wt% (excluding coexistence of Pb and Ca), P content less than 0.01 wt%, S and O ₂ contents of 0.00
It is less than 5 wt% and is a copper alloy consisting of the balance Cu and unavoidable impurities, and the size of crystallized substances or precipitates contained in the copper alloy is less than 3 μm, and the grain size of the copper alloy is less than 5 μm. A characteristic copper alloy for electronic devices.

The copper alloy of the present invention can be used for short-circuiting between pins such as a lead frame and for punching by defining the alloying element amount of precipitation hardening type copper alloy, the size of precipitates, the grain size and the like. It is intended to improve the dimensional accuracy and mold life.

According to the invention of claim 4, Cr is 0.1 to 0.4 w.
t%, Sn 0.05 to 2.0 wt%, Zn 0.05 to 2.0 wt%, Sr,
0.002 to 0.2 wt% of Ba and Bi in total, Zr
Less than 0.2 wt% (including 0 wt%), less than 0.01 wt% P,
S less than 0.005 wt%, O ₂ less than 0.005 wt%, balance Cu
And a copper alloy consisting of unavoidable impurities or Cr 0.1 to 0.
4wt%, Zr less than 0.2wt%, Sn 0.05-2.0wt%, Zn
0.05-2.0wt%, Sr, Ba, Bi one or more in total
0.002-0.2wt% included, P less than 0.01wt%, S 0.005wt%
Less, O ₂ is less than 0.005 wt%, and when a copper alloy consisting of the balance Cu and unavoidable impurities is subjected to casting, hot working, and cold working, the cooling rate during the casting is 5 ° C./sec or more. , 850 the copper alloy ingot obtained by the casting process
Heat to ~ 1000 ℃, hot work, cool at a rate of 10 ℃ / sec or more after hot work, then cold work at 300-500 ℃ at 10 ℃ / sec.
The method for producing a copper alloy for an electronic device according to claim 1, wherein the heat treatment is carried out once or more for minutes to 24 hours.

According to the invention of claim 5, 0.1 to 0.4 w of Cr is added.
t%, 0.05 to 2 wt% Zn, Co, Mg, Mn, Si, Sn
0.01 to 1 wt% in total, and 0.005 to 0.1 wt% in total for one or more Pb and Bi, and P content of 0.
Less than 01 wt%, S and O ₂ contents of less than 0.005 wt%, respectively, and a copper alloy consisting of the balance Cu and unavoidable impurities, or Cr of 0.1 to 0.4 wt%, Zr of less than 0.2 wt%, Zn of 0.05.
~ 2wt%, 0.01 to 1wt% of Co, Mg, Mn, Si and Sn in total, 0.005 to 0.1wt% of Pb and Bi in total and 0.01wt% of P %, S and O ₂ contents are each less than 0.005 wt%, and the balance Cu
When performing casting, hot working, or cold working on a copper alloy consisting of unavoidable impurities, the cooling rate during the casting is set to 5 ° C./sec or more, and a copper alloy ingot obtained by the casting is obtained. Heat to 850 to 1000 ℃ and hot work, quench rapidly at a rate of 10 ℃ / s or more after hot working, then cold work and
The method for producing a copper alloy for electronic devices according to claim 2, wherein the heat treatment is performed at 300 to 500 ° C for 10 minutes to 24 hours at least once.

In the invention according to claim 6, 0.1 to 0.4 w of Cr is added.
t%, 0.05 to 2 wt% Zn, Co, Mg, Mn, Si, Sn
0.01 to 1 wt% in total, and 0.005 to 0.1 wt% in total for Ca, Sr, Ba, and Pb and Bi.
Includes 0.005 to 0.2 wt% of one or more of Te in total (however, Pb
(Excluding the coexistence of Ca and Ca), the content of P is less than 0.01 wt%, S
And the content of O ₂ are each less than 0.005 wt% and the balance C
Copper alloy consisting of u and unavoidable impurities, or Cr of 0.1 to
0.4wt%, Zr less than 0.2wt%, Zn 0.05-2wt%, Co,
0.01 to 1 wt% of one or more of Mg, Mn, Si and Sn in total
In addition, 0.005 to 0.1w in total of one or more of Pb and Bi
0.005 of t%, one or more of Ca, Sr, Ba and Te in total
~ 0.2wt% (excluding coexistence of Pb and Ca), and further P
Content less than 0.01 wt%, S and O ₂ content respectively
When performing casting, hot working, or cold working on a copper alloy containing less than 0.005 wt% and the balance Cu and unavoidable impurities, the cooling rate during casting is set to 5 ° C./sec or more, The obtained copper alloy ingot is heated to 850 to 1000 ℃ and hot-worked. After hot-working, it is rapidly cooled at a rate of 10 ℃ / sec or more, then cold-worked and 300 to 500 ℃ for 10 minutes to 24 seconds. The method for producing a copper alloy for an electronic device according to claim 3, wherein the heat treatment is performed at least once.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the copper alloy of the present invention, Cr precipitates in copper and improves the strength without significantly lowering the conductivity of copper. The reason for limiting the content to 0.01 to 0.4 wt% is that if it is less than 0.01 wt%, sufficient strength and heat resistance cannot be obtained,
This is because if it exceeds 0.4 wt%, the improvement in strength is saturated and crystallized substances or precipitates become large, and these protrude from the end face of the lead frame and cause short circuits between adjacent pins or between leads. Like Cr, Zr is precipitated in copper and improves the strength of copper without significantly reducing the conductivity of copper. The reason for limiting the content to less than 0.2 wt% is that if the content is 0.2 wt% or more, the improvement in strength is saturated, and the precipitates become coarse, which causes a short circuit phenomenon of the lead frame, similar to Cr. S
n contributes to the improvement of strength. The reason for limiting the content to 0.05 to 2 wt% is that the effect is not sufficiently obtained if it is less than 0.05 wt%, and if it exceeds 2 wt%, the solid solution amount of Cr and Zr in copper is lowered, and This is because the size of crystallized substances and precipitates containing Zr becomes large, which causes a short circuit and causes a decrease in conductivity. Zn contributes to improvement of solderability and solder plating property, that is, prevention of peeling of the solder layer. Its content is 0.05 ~
The reason for limiting the content to 2 wt% is that if it is less than 0.05 wt%, the effect cannot be sufficiently obtained, and if it exceeds 2 wt%, the solderability is rather deteriorated.

In the invention according to claim 1, Sr, B
a and Bi improve punching workability. The punching workability here means the dimension and shape of the punching end surface, the degree of burr generation,
It is evaluated by the life of the punching die. The reason why the total content of one or more of Sr, Ba, or Bi is limited to 0.002 to 0.2 wt% is that the effect is not sufficiently obtained if it is less than 0.002 wt%,
This is because if it exceeds 0.2 wt%, cracks or the like will occur during rolling.

In the invention according to claim 2, Co, M
g, Mn, Si, and Sn promote uniform and fine precipitation of Cr or Cr and Zr, and also contribute to strength improvement. The reason for limiting the total content to 0.01-1 wt% is 0.01 wt
If it is less than%, the effect cannot be sufficiently obtained, and if it exceeds 1 wt%, the solid solution amount of Cr and Zr in copper is reduced, and the size of precipitates containing Cr and Zr becomes large, which causes a short circuit. This is because the conductivity is lowered. If one or more of Pb and Bi are contained, punching workability is improved. Here, the punching workability is evaluated by the dimension and shape of the punching end surface, the degree of burr generation, the life of the punching die, etc., as described above. Pb, B
Although i alone disperses in the Cu matrix and contributes to the improvement of i, the improvement effect is particularly remarkable. The P
The reason why the total content of at least one of b and Bi is limited to 0.005 to 0.1 wt% is that the effect is not sufficiently obtained if it is less than 0.002 wt%, and if it exceeds 0.1 wt%, defects such as cracks are generated during rolling. This is due to the decrease in productivity.

In the invention according to claim 3, Co, M
The action of g, Mn, Si, and Sn and the reason for limiting the content are the same as in the case of the invention of claim 2. The present invention provides one or more of Pb and Bi with Ca, Sr, Ba and Te.
Further, at least one of the above is further contained to further improve the punching workability. Here, the punching workability is evaluated by the size and shape of the punching end surface, the degree of burr generation, the life of the punching die, etc., and Pb and Bi are dispersed alone in the Cu matrix,
As described above, the effect of improvement is particularly remarkable. C newly contained here
a, Sr, Ba, Te form an intermetallic compound with Cu, which is dispersed in the Cu matrix,
Contribute to the improvement of. One or more of Pb and Bi, and Ca and S
Various pressability is improved by adding an appropriate amount of one or more of r, Ba and Te. However, if Pb and Ca coexist, the effect cannot be sufficiently obtained. The reason why the total content of at least one of Pb and Bi is limited to 0.005 to 0.1 wt% is as described above. The reason why the total content of at least one of Ca, Sr, Ba and Te is limited to 0.005 to 0.2 wt% is that the effect is not sufficiently obtained if it is less than 0.005 wt%, and if it exceeds 0.2 wt% during rolling. This is because cracks and the like occur and productivity decreases.

In the present invention, in addition to the above-mentioned alloying elements, the amounts of P, S, O ₂ etc. contained in trace amounts in ordinary industrial copper materials are also defined. By defining the content of P to be less than 0.01 wt%,
In the alloy of the present invention, coarsening of crystallized substances such as Cr-P system is suppressed and short circuit between pins is prevented. Especially the content of P
Less than 0.005 wt% is desirable. By defining the content of S to be less than 0.005 wt%, coarsening of crystallized substances such as Cr—S type and Zr—S type is suppressed and short circuit between pins is prevented. Further, hot workability is improved. Particularly, the S content is preferably less than 0.002 wt%. O ₂ is C when its content is 0.005 wt% or more.
R and Zr are oxidized, precipitation hardening cannot be sufficiently obtained, and solderability is deteriorated. Especially the content of O ₂ is 0.002wt%
Less than is desirable. As described above, P, S, and O ₂ can significantly improve the properties of a precipitation hardening copper alloy containing Cr or Zr as a lead frame material, etc., by properly defining the contents. is there. This is the first finding of the present inventors.

In the present invention, the size of the crystallized substances or precipitates contained in the copper alloy is defined to be less than 3 μm, because the crystallized substances or the precipitates have a size of 3 μm or more. This is because the precipitate is formed into a needle shape or a plate shape during the rolling process and protrudes from the end portion of the lead, and a short circuit easily occurs between pins of the lead frame and between the leads.

In the invention of claim 1, the reason why the grain size of the copper alloy is specified to be less than 5 μm is that the grain size is 5 μm.
This is because the above-described effect of improving the punching workability of Sr, Ba, or Bi cannot be sufficiently obtained. The crystal grain size is 5 μm
If it is less than the above range, there is an advantage that the etched surface becomes smooth and the plating property is improved.

In the invention of claim 2, the reason why the grain size of the copper alloy is limited to less than 5 μm is that P is 5 μm or more.
This is because the punching workability improving effect obtained by containing at least one of b and Bi cannot be sufficiently obtained. Further, the effect of setting the crystal grain size to less than 5 μm is as described above.

In the invention of claim 3, the reason why the grain size of the copper alloy is limited to less than 5 μm is that P is 5 μm or more.
b, one or more of Bi, and 1 of Ca, Sr, Ba, Te
This is because the effect of improving the punching workability obtained by containing at least one species (excluding the coexistence of Pb and Ca) cannot be sufficiently obtained. Further, the effect of setting the crystal grain size to less than 5 μm is as described above.

The precipitation hardening type copper alloy of the present invention is cast, hot worked and cold worked into a predetermined shape. In the inventions according to claims 3, 4, and 5, the reason why the cooling rate during the casting process is 5 ° C / sec or more is that the cooling rate is 5 ° C.
If it is less than / sec, large crystallized substances exceeding 3 μm (Cr, Cu
This is because various crystallized substances such as -Zr type) are generated. The hot working temperature of the copper alloy ingot obtained by the casting process is 850
The reason for defining to 1000 ℃ is that Cr and Zr are below 850 ℃.
The reason for this is that the crystallized substances and precipitates of No. 1 become large and eventually the conditions of the present invention are not satisfied, and when the temperature exceeds 1000 ° C., the oxide film becomes thick and the productivity is impaired and the energy cost increases. The reason why the cooling after the hot working is performed at a rate of 10 ° C / sec or more is that when the cooling rate is less than 10 ° C / sec, C
This is because crystallized substances or precipitates such as r and Zr grow to a size exceeding 3 μm. The heat treatment during the cold working is 300
The reason why the condition of 10 minutes to 24 hours at ~ 500 ° C is specified is that if the heat treatment temperature is less than 300 ° C or less than 10 minutes, fine precipitation of Cr and Zr dissolved in the copper alloy becomes insufficient, and lead This is because the balance of characteristics as a frame material is lost. If it exceeds 500 ° C, the grain size becomes large and the punching workability deteriorates. If it exceeds 24 hours, the effect is saturated and it is uneconomical. Also, after cold working with the above heat treatment, finish cold working and slightly lower temperature (200-400 ℃)
Bending workability and anisotropy are improved by heat treatment at
Also, internal stress is removed. The low temperature heat treatment is preferably performed in a reducing atmosphere or an inert atmosphere, and the heat treatment method may be a batch type or a running type such as tension annealing. If necessary, straightening such as a tension leveler or a roller leveler may be performed before and after the heat treatment.

[0021]

The present invention will be described below in detail with reference to examples. (Example 1) An alloy having the composition shown in Table 1 was melted in a high frequency melting furnace, and this was cooled at a cooling rate of 6 ° C / second to a thickness of 30 mm and a width of 1 mm.
It was cast into an ingot with a length of 00 mm and a length of 150 mm. Next, ingot 9
It was hot-rolled at 80 ° C and then immediately quenched at a rate of 30 ° C / sec. Both surfaces of this hot rolled material were chamfered by 9 mm to remove the oxide film, and then cold rolled to a thickness of 0.33 mm. Then heat-treat at 420 ℃ for 2 hours in an inert atmosphere, and further finish cold-rolling to a plate with a thickness of 0.2 mm.
Heat treated at 2 ° C. for 2 hours.

The various characteristics required of the lead frame for each of the plate materials thus obtained are described below.
It investigated by the method of. Table 2 shows the results. Crystallized substances, precipitates, crystal grain size: Microscopic observation (200
Times). Tensile strength: Measured according to JIS Z2241. Conductivity: Measured according to JIS H0505. Presence or absence of protrusions on the etched surface: A test piece with a width of 0.5 mm was cut out by etching in the direction perpendicular to the rolling direction, and the etched surface was observed under a microscope (50 times). A ferric chloride solution was used as the etching solution. Solder wettability: A test piece of 10 mm x 50 mm was dipped in a rosin-based (RMA) flux for 5 seconds, and then eutectic solder (Pb-6
It was immersed in a 3 wt% Sn) bath for 5 seconds, and the wet condition of the solder was visually observed. A wet area of 90% or more was judged as good, and a wet area of less than 90% was judged as poor. Solder adhesion: The solder adhesion test piece was heated in the atmosphere at 150 ° C. for 1000 hours in the same manner as in (1) and then subjected to 180 degree contact bending and bending back, and then the solder adhesion was visually observed. Punching performance: A 1 mm x 5 mm square hole was opened with a SKD11 die, and 20 samples were randomly extracted from the punching times from the 5001st to 10,000th times, and the size (height I) of the burr of these samples was determined. It was measured. Further, the punched surface was observed to measure the thickness a of the fractured portion, and the ratio of the fractured portion (a / b) × 100% to the thickness b of the test piece was determined. This ratio is regarded as one of the criteria of punching property, and it is said that the larger this value is, the better the punching property is, and it is evaluated that the yield is improved and the precise processing can be performed.

[0023]

[Table 1]

[0024]

[Table 2]

As is clear from Table 2, No. 1 of the invention example
All of ~ 13 exhibited excellent characteristics. On the other hand, Comparative Examples Nos. 14 and 17 both had low strength. This is because the former has a smaller amount of Cr and the latter has a smaller amount of Sn. No.15,16
A protrusion was observed on the etched surface. This is Cr
Alternatively, the amount of Zr is large. These protrusions cause a short circuit and are unsuitable as a lead frame material. Since No. 18 had a large amount of Sn, it had high strength but low conductivity. In addition, a protrusion that causes a short circuit was recognized on the etched surface. No. 19 had a small amount of Zn, and therefore solder peeling was observed. N
In o.20, the solder wettability deteriorated due to the large amount of Zn. No. 21 had a large burr in the punching test. This is because the total amount of Sr and Bi is small. Further, the ratio of the fractured surface to the punched surface was small, and it was impossible to perform very precise molding.
Since No. 22 had a large total amount of Sr, Ba, and Bi, cracking occurred during hot rolling. Nos. 23 and 24 contained a large amount of P or S, and thus the crystallized substances were coarsened and the protrusions remained on the etched surface. N
O.25 had a large amount of O _{2 and} thus sufficient precipitation hardening was not obtained and the strength decreased. It was also inferior in solder wettability.

(Example 2) Nos. Of alloys of the present invention shown in Table 1
Casting, hot rolling, cooling, heat treatment, and cold rolling on 3,6,9,13 under the conditions shown in Table 3
The characteristics were examined by the same method as in Example 1. The results are shown in Table 4. Note that Nos. 3, 6, 9, and 13 shown in Tables 1 and 2 are reprinted.

[0027]

[Table 3]

[0028]

[Table 4]

As is clear from Table 4, No.
All of 31 to 36 show excellent characteristics. On the other hand, in Comparative Examples No. 41 and 48, the cooling rate during casting was slow, No. 42 had a low hot working temperature, and No. 43 had a slow cooling rate after hot working. Therefore, in both cases, crystallized substances and precipitates became coarse, and these were made acicular or plate-like by hot working or cold working and remained as projections on the etched surface. N
The tensile strength of o.42 and 43 also decreased. No.44,47,49 had a high grain size because the heat treatment temperature during cold working was high, resulting in lower strength and larger burrs than No.3,9,13 of the present invention. In addition, the ratio of fractured parts (precision workability) decreased. In No. 45, the hot working temperature exceeded 1000 ° C, so a thick oxide film was formed on the rolled material. The characteristics of No. 45 are N of the invention example.
It is equivalent to o.3, and it turns out that hot working at a temperature over 1000 ° C only increases the energy cost and is meaningless. In No. 46, the annealing temperature after cold working was low, so both strength and conductivity decreased.

Example 3 An alloy having the composition shown in Table 5 was melted in a high frequency melting furnace and cast into a ingot having a thickness of 30 mm, a width of 100 mm and a length of 150 mm at a cooling rate of 6 ° C./sec. did. Next, this ingot was hot-rolled at 980 ° C. and immediately thereafter rapidly cooled at a rate of 30 ° C./sec. In order to remove the oxide film on the surface of this hot rolled material, it was chamfered to a thickness of 9 mm and then cold rolled to a thickness of 0.33 mm. Next, heat-treat at 440 ℃ for 2 hours in an inert atmosphere, and further finish cold-rolling to a plate with a thickness of 0.2 mm.
This was heat-treated at 350 ° C. for 2 hours in an inert atmosphere. With respect to the respective plate materials thus obtained, various characteristics (-) required for the lead frame were examined by the same method as in Example 1. Furthermore, after re-polishing the die for which the punching workability was investigated, punching was performed again,
Twenty samples were randomly extracted from the punching up to the 00th time, and the size (height II) of the burr was measured. This burr becomes larger as the die wear becomes more severe and becomes an index of die life. Table 6 shows the results. In Table 5, Co, M
g, Mn, Si, Sn as the first group additive element (first group element),
Pb, Bi as the second group additive element (second group element), Ca, S
r, Ba, and Te are the third group additive elements (third group elements).

[0031]

[Table 5]

[0032]

[Table 6]

As is clear from Table 6, No.
All of 51 to 62 showed excellent characteristics. In contrast, Comparative Examples Nos. 63 and 66 had low strength. The former is C
The amount of r and the latter are because the amounts of the first group additive elements are small. Nos. 64 and 65 had protrusions on the etched surface. This is because the amount of Cr or Zr is large. These protrusions cause a short circuit and are unsuitable as a lead frame material. In No. 67, the electrical conductivity was low although the strength was high due to the large amount of elements added in the first group. In addition, a protrusion that causes a short circuit was recognized on the etched surface. In No. 68, the amount of Zn was small, and therefore solder peeling was observed. No. 69 had a large amount of Zn, so the solder wettability deteriorated. . In No. 70, the ratio of the fracture surface on the punching surface was small and the burr was large in the punching test. Also, the burrs in the die life test were large. this is,
This is because the amount of the second and third group additive elements is small. No.71,72
Has a large total amount of Pb, Bi, Ca, Sr, Ba, Te, etc., so that cracking occurred during hot rolling. In Nos. 73 and 74, since the amount of P or S was large, the crystallized substances were coarsened and protrusions were recognized on the etched surface. Further, in No. 73, since Pb and Ca coexist, the effect of improving punchability (burr height I, II, fracture ratio) cannot be sufficiently obtained. In No. 75, the amount of O ₂ was large, so that sufficient precipitation hardening could not be obtained and the strength decreased. Also, the solder wettability was poor.

Example 4 Alloy No. 53 of the present invention shown in Table 5
Using 58, 60 and 62, casting, hot rolling, cooling, heat treatment and cold rolling were performed under the conditions shown in Table 7, and the properties of the obtained plate material were examined by the same method as in Example 1. Table 8 shows the results. Inventive Example Nos. 53 and 5 shown in Tables 5 and 6
Re-posted 8,60,62.

[0035]

[Table 7]

[0036]

[Table 8]

As is clear from Table 8, No.
All of 81 to 86 show excellent characteristics. On the other hand, in Comparative Examples No. 87 and 94, the cooling rate during casting was slow, No. 88 had a low hot working temperature, and No. 89 had a slow cooling rate after hot working. Therefore, in both cases, crystallized substances and precipitates were coarsened, which became needle-like or plate-like during hot working or cold working, resulting in protrusions on the etched surface. No.8
The tensile strength of 8,89 also decreased. No. 90, 93, 95 had a high heat treatment temperature during cold working, so the grain size increased,
Compared with No. 53, 60, 62 of the present invention example, the tensile strength decreased, the burr was large, and the fracture ratio and the burr after the die life test were also greatly increased. In No. 91, the hot working temperature exceeded 1000 ° C, so a thick oxide film was formed on the rolled material. No.91
The characteristics of No. 53 are equivalent to those of No. 53 of the present invention, and it is understood that hot working at a temperature exceeding 1000 ° C. only causes an increase in energy cost and is meaningless. In No. 92, the annealing temperature after hot working was low, so both the tensile strength and conductivity decreased.

[0038]

As described above, the copper alloy for electronic devices of the present invention is excellent in strength and conductivity, and is also excellent in solderability, punching property and etching property. It is possible to suitably cope with the recent trend toward higher density and higher integration of electronic equipment. Further, it can be suitably applied to a multi-pin lead frame having a large number of pins. The present invention is suitable for lead frames, but in addition to lead frames, terminals,
It is also suitable as a general conductive material such as a connector and an electrode. Thus, the present invention has an industrially remarkable effect.

Claims (6)

[Claims] 1. Cr: 0.1 to 0.4 wt%, Sn: 0.05 to 2.0 w
t%, 0.05 to 2.0 wt% Zn, one or more of Sr, Ba, Bi
0.002 to 0.2 wt%, Zr less than 0.2 wt% (0 wt%
Included), P less than 0.01wt%, S and O_TwoContent of
Less than 0.005 wt% each, balance Cu and unavoidable impurities
Copper alloy consisting of 0.1-0.4wt% Cr, 0.2w Zr
less than t%, Sn 0.05 to 2.0 wt%, Zn 0.05 to 2.0 wt%, S
Contains 0.002 to 0.2 wt% of one or more of r, Ba and Bi in total.
, P less than 0.01 wt%, S and O _TwoContent of
Less than 0.005wt%, balance Cu and unavoidable impurities
A copper alloy, and a crystallized substance or precipitation contained in the copper alloy
The size of the object is less than 3μm, the grain size of the copper alloy is 5μ
A copper alloy for electronic devices, which is less than m. 2. Cr: 0.1-0.4 wt%, Zn: 0.05-2 wt%
%, One or more of Co, Mg, Mn, Si and Sn in total
0.01 to 1 wt% is included, and at least one of Pb and Bi is added in total.
0.005 to 0.1 wt%, P content less than 0.01 wt%, S content and O ₂ content less than 0.005 wt% respectively, balance Cu
And a copper alloy consisting of unavoidable impurities or Cr 0.1 to 0.
4wt%, Zr less than 0.2wt%, Zn 0.05-2wt%, Co, M
0.01 to 1 wt% in total of one or more of g, Mn, Si and Sn, and 0.005 to 0.1 wt% in total of one or more of Pb and Bi
A copper alloy containing P, the content of P is less than 0.01 wt%, the contents of S and O ₂ are each less than 0.005 wt%, and the balance Cu and unavoidable impurities. A copper alloy for electronic devices, wherein the size of the object is less than 3 μm, and the grain size of the copper alloy is less than 5 μm. 3. Cr: 0.1-0.4 wt%, Zn: 0.05-2 wt%
%, One or more of Co, Mg, Mn, Si and Sn in total
0.01 to 1 wt% is included, and at least one of Pb and Bi is added in total.
0.005 to 0.1 wt%, including one or more of Ca, Sr, Ba and Te in a total amount of 0.005 to 0.2 wt% (excluding coexistence of Pb and Ca), P content of less than 0.01 wt%, S and O Each of the contents of ₂ is less than 0.005 wt%, the balance is a copper alloy consisting of Cu and unavoidable impurities, or Cr is 0.1 to 0.4 wt% and Zr is 0.
Less than 2wt%, 0.05 to 2wt% of Zn, Co, Mg, Mn, S
0.01 to 1 wt% in total of at least one of i and Sn, and P
b, Bi one or more in total 0.005-0.1wt%, Ca, S
Includes 0.005 to 0.2 wt% in total of one or more of r, Ba and Te (excluding coexistence of Pb and Ca), and contains P in 0.01 wt%
The content of S and O ₂ is less than 0.005 wt%, and the balance is Cu and unavoidable impurities, and the size of crystallized substances or precipitates contained in the copper alloy is less than 3 μm. A copper alloy for electronic devices, wherein the crystal grain size of the copper alloy is less than 5 μm. 4. Cr: 0.1-0.4 wt%, Sn: 0.05-2.0 w
t%, Zn 0.05-2.0 wt%, Sr, Ba, Bi at least one 0.002-0.2 wt% in total, Zr less than 0.2 wt% (including 0 wt%), P less than 0.01 wt%, S less than 0.005 wt%, O
₂ is less than 0.005 wt%, the balance is a copper alloy consisting of Cu and unavoidable impurities, or Cr is 0.1 to 0.4 wt%, Zr is less than 0.2 wt%, Sn is 0.05 to 2.0 wt%, Zn is 0.05 to 2.0 wt%, Sr,
Including 0.002 to 0.2 wt% in total of one or more of Ba and Bi, P
Is less than 0.01 wt%, S is less than 0.005 wt%, O ₂ is less than 0.005 wt%, and the balance is a copper alloy consisting of Cu and inevitable impurities.
When performing casting, hot working, or cold working, the cooling rate during the casting is set to 5 ° C / sec or more, and the copper alloy ingot obtained by the casting is heated to 850 to 1000 ° C and heated. Cold working, cool at a rate of 10 ℃ / s or more after hot working, then cold work at 300 to 500 ℃ for 10 minutes to 24 hours heat treatment 1
The method for producing a copper alloy for an electronic device according to claim 1, wherein the method is performed more than once. 5. 0.1 to 0.4 wt% of Cr and 0.05 to 2 wt% of Zn
%, One or more of Co, Mg, Mn, Si and Sn in total
0.01 to 1 wt% is included, and at least one of Pb and Bi is added in total.
0.005 to 0.1 wt%, P content less than 0.01 wt%, S content and O ₂ content less than 0.005 wt% respectively, balance Cu
And a copper alloy consisting of unavoidable impurities or Cr 0.1 to 0.
4wt%, Zr less than 0.2wt%, Zn 0.05-2wt%, Co, M
0.01 to 1 wt% in total of one or more of g, Mn, Si and Sn, and 0.005 to 0.1 wt% in total of one or more of Pb and Bi
In addition, the P content is less than 0.01 wt%, the content of S and O ₂ is less than 0.005 wt% respectively, and the casting, hot working, and cold working are performed on the copper alloy containing the balance Cu and unavoidable impurities. The cooling rate at the time of casting is set to 5 ° C./sec or more, and the copper alloy ingot obtained by the casting is 850 to 10
Heat to 00 ℃ to hot work, quench rapidly after hot working at a rate of 10 ℃ / s or more, then cold work and 10 to 300-500 ℃.
The method for producing a copper alloy for an electronic device according to claim 2, wherein the heat treatment for minutes to 24 hours is performed at least once. 6. Cr: 0.1-0.4 wt%, Zn: 0.05-2 wt%
%, One or more of Co, Mg, Mn, Si and Sn in total
0.01 to 1 wt% is included, and at least one of Pb and Bi is added in total.
0.005 to 0.1 wt%, including one or more of Ca, Sr, Ba and Te in a total amount of 0.005 to 0.2 wt% (excluding coexistence of Pb and Ca), P content of less than 0.01 wt%, S and O Each of the contents of ₂ is less than 0.005 wt%, the balance is a copper alloy consisting of Cu and unavoidable impurities, or Cr is 0.1 to 0.4 wt% and Zr is 0.
Less than 2wt%, 0.05 to 2wt% of Zn, Co, Mg, Mn, S
0.01 to 1 wt% in total of at least one of i and Sn, and P
b, Bi one or more in total 0.005-0.1wt%, Ca, S
Includes 0.005 to 0.2 wt% in total of at least one of r, Ba, and Te (excluding coexistence of Pb and Ca), and further includes P content of 0.01
When performing casting, hot working, or cold working on a copper alloy containing less than wt% and contents of S and O ₂ of less than 0.005 wt% respectively and the balance Cu and unavoidable impurities, cooling during the casting The speed is set to 5 ° C / sec or more, the copper alloy ingot obtained by the casting process is heated to 850 to 1000 ° C to perform hot working, and after hot working, rapidly cooled at a rate of 10 ° C / s or more, and then 4. The method for producing a copper alloy for electronic equipment according to claim 3, wherein cold working and heat treatment at 300 to 500 [deg.] C. for 10 minutes to 24 hours are performed at least once.