JPH0438828B2

JPH0438828B2 -

Info

Publication number: JPH0438828B2
Application number: JP8204087A
Authority: JP
Priority date: 1987-04-02
Filing date: 1987-04-02
Publication date: 1992-06-25
Also published as: JPS63247320A

Description

[Detailed description of the invention]

［産業上の利用分野］本発明は半導体用リードフレーム材等の電気・
電子部品に使用される銅合金の製造方法に関す
る。［従来技術］従来、半導体用リードフレーム材としては、素
子およびセラミツクスと線膨張係数が近似しさら
に高い強度も有する42アロイが多く使用されて来
た。しかし近年、素子の接着技術および封着材の改
善に伴い、42アロイにかわり、熱放散性に優れ、
しかも価格も安い銅系材料が使用される様になつ
てきた。特に集積回路用リードフレーム材には、
最近の素子の高集積化の傾向から、素子で発生す
るジユール熱を効率良く放散させるため、より熱
伝導性（即ち導電性）の高いリードフレーム材料
が求められる様になつてきた。一方、高密度実装化に伴う集積回路の小形化の
傾向から、リードフレーム材料も薄板化し、より
高い強度も同時に求められている。従つて高い導
電性とともに42アロイと同様の高い強度も併せ備
えた銅系材料がリードフレーム材料として要求さ
れている。この様な高い導電性と高い強度を有す
る銅合金は半導体用リードフレーム材料に限らず
広く電気・電子部品に使用される導電部材として
利用され得る。ところで上記の様に高い導電性と
高い強度を併せ備える銅合金としてはCu−Ni−
Si−Zn系、Cu−Ni−Si−Sn−Zn系の合金が知ら
れている。上記合金系は、Ni，Siの金属間化合物を微細
に析出させることにより銅合金の持つ高い導電性
を損なうことなく高い強度を実現させており、特
性的には上記要求を満足するものである。しかし、これらの合金系は熱間圧延が困難な合
金であり、Mg，Cr，Zr，Ti等の元素添加により
Ｓの固定あるいは粒界の強化を行なつたり、Pb，
Bi等の低融点不純物の量を規制することにより
熱間圧延性が大巾に改善されてはいるが、完全で
はなく製造条件のばらつきにより熱間圧延時にエ
ツジ割れ等の不具合が、まれに発生することがあ
り、熱間圧延歩留りを低下させているという問題
を有している。［発明が解決しようとする問題点］本発明は上記に説明した従来技術の鑑みなされ
たものであり、Cu−Ni−Si−Zn系合金、Cu−Ni
−Si−Sn−Zn系合金が有する熱間圧延性を改善
することにより高強度・高導電性銅合金を歩留り
良く製造する方法を提供する目的でなされたもの
である。［問題点を解決するための手段］本発明に係る第１発明の電気・電子部品用銅合
金の製造方法は、Ni：1.0〜3.5％，Si：0.2〜0.9
％，Zn：0.1〜5.0％を含有し、Mg，Cr，Zr，Ti
のうち１種または２種以上を0.001〜0.01％含有
し、残部Cuおよび不可避不純物からなる合金溶
湯の鋳造工程で、鋳塊表面層のNi₂Si化合物の析
出量を0.1％以下に抑制して鋳造する電気・電子
部品用銅合金製造方法であり、第２の発明では、
電気・電子部品用銅合金の製造工程において、
Ni：1.0〜3.5％，Si：0.2〜0.9％，Zn：0.1〜5.0
％，Sn：0.1〜2.0％を含有し、Mg，Cr，Zr，Ti
のうち１種または２種以上を0.001〜0.01％含有
し、残部Cuおよび不可避不純物からなる合金溶
湯の鋳造工程で鋳塊表面層のNi₂Si化合物の析出
量を0.08％以下に抑制して鋳造する電気・電子部
品用銅合金の製造方法である。［作用］以下に本発明の製造方法で使用する銅合金の成
分および成分割合について説明する。 Niは強度を付与する元素であり、含有量が1.0
％未満ではSiが0.2〜0.9％含有されていても強度
および耐熱性は向上せず、また、3.5％を越えて
含有されると銅電率が低下し、かつ、不経済であ
る。よつて、Ni含有量は1.0〜3.5％とする。 SiはNiと共に強度を付与する元素であり、含
有量が0.2％未満ではNiが1.0〜3.5％含有されてい
ても強度および耐熱性は向上せず、また、0.9％
を越えて含有されると導電性が低下すると共に熱
間加工性が悪化する。よつて、Si含有量は0.2〜
0.9％とする。 Znは、めつきされた錫およびはんだの耐熱剥
離性を著しく改善する元素であり、含有量が0.1
％未満ではこの効果が少なく、また、5.0％を越
えて含有されるとはんだ付け性が悪化する。よつ
て、Zn含有量は0.1〜5.0％とする。 Mg，Cr，Ti，Zr、は何れの元素も熱間加工性
を向上させる元素であり、含有量が0.001％未満
ではこの効果は少なく、また、0.01％を越える含
有量では造塊時の湯流れ性が悪化し、造塊歩留り
が低下する。よつて、Mg，Cr，Ti，Zr含有量は
0.001〜0.01％とする。また、Mg，Cr，Ti，Zrの
２種以上を含有する場合も上記に説明した同じ理
由から合計含有量は0.001〜0.01％とする。さらに、Snは本発明の第２発明の必須元素で
あり、Snは強度、ステイフネス強度および繰り
返し曲げ性の向上に寄与する元素であり、含有量
が0.1％未満ではこれらの効果が少なく、また、
2.0％を越えて含有されると導電性、耐熱性およ
び熱間加工性を低下させる。よつて、第２発明に
おけるSn含有量は0.1〜2.0％とする。次に製造方法について説明する。本合金は熱間圧延が困難であり、以下に述べる
方法を適用せずに熱間圧延を行なうと粒界割れが
発生し歩留りを低下させる。本発明者は、上記の原因を調べた結果、割れの
原因は、鋳塊を熱間圧延温度に迄加熱する過程に
おいて、第１図に示すこの合金が有する中間温度
脆性域を通過する際に、鋳塊が有する残留応力と
加熱による熱応力により粒界が脆化することによ
るものであることを見い出した。さらに、この粒界の脆化は鋳塊が含有する金属
間化合物Ni₂Siの含有量が多くなる程感受性が高
まり、その含有量が第１発明においては0.1％以
下であれば、また、Suを含む第２発明において
は0.08％以下であれば通常の鋳塊が有する程度の
大きさの残留応力は、通常の加熱条件により鋳塊
が加熱されても割れに至る粒界脆化を起こさない
ことを見い出した。次に鋳塊が含有するNi₂Si量を第１発明におい
ては、0.1％に第２発明においては0.08％に抑え
る方法としては、鋳塊時の冷却速度を大きくすれ
ば良く、モールドの材質を熱伝導性の良い銅を使
用したり、鋳塊の厚さを薄くして冷却を効かせる
等の方法が考えられる。尚、通常の鋳塊は熱間圧延時の割れを考慮する
と、外周部の割れが問題となる。したがつて、外
周部でのNi₂Si含有量が少ないことが重要であ
る。すなわちNi₂Si含有量が多いと、Ni，Siが金
属間化合物Ni₂Siの形で析出することにより、
Ni，Siが固溶している状態よりも粒内の強度が
上まり、粒界への応力集中が大きくなる。また加
熱時の残留応力の緩和が遅れる。以上の結果、粒界脆化を起し易くなる。［実施例］実施例１第１表に示す組成の合金を大気溶解し、半連続
鋳造により410mmｗ×150mmｔ×3000mmの鋳塊を
造塊した。鋳造条件は第２表に示す。この鋳塊を850℃の
温度で熱間圧延試験を行ない15mmｔの厚さにし
た。鋳塊のNi₂Si含有量の調査結果および熱間圧
延試験結果を第２表に示す。Ni₂Si含有量は鋳塊
の外周部から20mmの位置から採取した試料を硝酸
（硝酸３対水１）で溶解し、不溶解残渣として沈
殿したしたNi₂Siをろ紙で補集し、その重量を測
定することにより求めた。第２表に示すようにNo.１，２，３は本発明の第
１発明に係る実施例でありNi₂Siの析出量が0.1％
以下であるため熱間圧延による割れは発明しな
い。第２表においてNo.４，５，６，は本第１発明の
実施例に対する比較例でNi₂Siの析出量が0.1％を
越えるため、熱間圧延においてエツジ割れが発生
している。［実施例］実施例２第３表に示す組成の合金を大気溶解し、半連続
鋳造により410mmｗ×150mmｔ×3000mmの鋳塊を
造塊した。鋳造条件は第４表に示す。この鋳塊を850℃の
温度で熱間圧延試験を行ない15mmｔの厚さにし
た。鋳造のNi₂Si含有量の調査結果および熱間圧延
試験結果を第４表に示す。Ni₂Si含有量は鋳塊の
外周部から20mmの位置から採取した試料を、硝酸
（硝酸３対水１）で溶解し、不溶解残渣として沈
殿したNi₂Siをろ紙で補集し、その重量を測定す
ることにより求めた。第４表に示すように、No.１，２，３は本発明の
第２発明に係る実施例でありNi₂Siの析出量が
0.08％以下あるため熱間圧延による割れは発生し
ない。第４表においてNo.４、５、６は本第２発明
の実施例に対する比較例であり、Ni₂Siの析出量
が0.08％を越えるため、熱間圧延においてエツジ
割れが発生している。［発明の効果］以上説明したように、本発明に係る第１発明の
銅合金の製造方法により、高い強度と高い導電率
を併せ備えた電気・電子部品用銅合金を歩留り良
く製造することができ、また、本発明に係る第２
発明の銅合金の製造方法は高い導電率とさらに高
い強度を併せ備えた電気・電子部品用合金を歩留
り良く製造することができる。 [Industrial Application Field] The present invention is applicable to electrical and electrical applications such as lead frame materials for semiconductors.
This invention relates to a method for producing copper alloys used in electronic parts. [Prior Art] Conventionally, 42 alloy, which has a linear expansion coefficient similar to that of elements and ceramics and also has high strength, has been often used as a lead frame material for semiconductors. However, in recent years, with the improvement of element adhesion technology and sealing materials, 42 alloy has been replaced, with excellent heat dissipation.
Moreover, copper-based materials, which are inexpensive, have come to be used. Especially for lead frame materials for integrated circuits,
With the recent trend toward higher integration of devices, lead frame materials with higher thermal conductivity (that is, electrical conductivity) have been required in order to efficiently dissipate the Joule heat generated in the devices. On the other hand, as integrated circuits tend to become smaller due to higher density packaging, lead frame materials are becoming thinner and higher strength is also required. Therefore, a copper-based material that has both high conductivity and high strength similar to 42 alloy is required as a lead frame material. Copper alloys having such high conductivity and high strength can be used not only as lead frame materials for semiconductors but also as conductive members used in a wide range of electrical and electronic components. By the way, as mentioned above, Cu-Ni- is a copper alloy that has both high conductivity and high strength.
Si-Zn alloys and Cu-Ni-Si-Sn-Zn alloys are known. The above alloy system achieves high strength without impairing the high conductivity of the copper alloy by finely precipitating intermetallic compounds of Ni and Si, and in terms of characteristics, it satisfies the above requirements. . However, these alloy systems are difficult to hot-roll, and it is necessary to fix S or strengthen the grain boundaries by adding elements such as Mg, Cr, Zr, and Ti, and to strengthen the grain boundaries by adding elements such as Mg, Cr, Zr, and Ti.
Although hot rolling properties have been greatly improved by controlling the amount of low-melting point impurities such as Bi, it is not perfect and defects such as edge cracking occasionally occur during hot rolling due to variations in manufacturing conditions. This has the problem of lowering the hot rolling yield. [Problems to be Solved by the Invention] The present invention has been made in view of the prior art described above.
This was done with the purpose of providing a method for manufacturing high-strength, high-conductivity copper alloys with good yield by improving the hot rolling properties of -Si-Sn-Zn alloys. [Means for Solving the Problems] The method for producing a copper alloy for electrical/electronic parts according to the first invention according to the present invention includes Ni: 1.0 to 3.5%, Si: 0.2 to 0.9%.
%, Zn: 0.1-5.0%, Mg, Cr, Zr, Ti
In the casting process of a molten alloy containing 0.001 to 0.01% of one or more of these, the balance being Cu and unavoidable impurities, the amount of Ni ₂ Si compound precipitation on the ingot surface layer is suppressed to 0.1% or less. A method for producing a copper alloy for electric/electronic parts by casting, in a second invention,
In the manufacturing process of copper alloys for electrical and electronic parts,
Ni: 1.0~3.5%, Si: 0.2~0.9%, Zn: 0.1~5.0
%, Sn: Contains 0.1-2.0%, Mg, Cr, Zr, Ti
In the casting process of a molten alloy containing one or more of these in an amount of 0.001 to 0.01% and the balance consisting of Cu and unavoidable impurities, the amount of Ni ₂ Si compound precipitation in the ingot surface layer is suppressed to 0.08% or less. This is a method for producing copper alloys for electrical and electronic parts. [Function] The components and component ratios of the copper alloy used in the manufacturing method of the present invention will be explained below. Ni is an element that gives strength, and the content is 1.0
If it is less than 3.5%, the strength and heat resistance will not improve even if Si is contained in an amount of 0.2 to 0.9%, and if it is contained in more than 3.5%, the copper conductivity will decrease and it will be uneconomical. Therefore, the Ni content is set to 1.0 to 3.5%. Si is an element that imparts strength together with Ni, and if the content is less than 0.2%, the strength and heat resistance will not improve even if Ni is contained at 1.0 to 3.5%;
If the content exceeds the above range, the conductivity and hot workability will deteriorate. Therefore, the Si content is 0.2~
The rate shall be 0.9%. Zn is an element that significantly improves the heat peeling properties of plated tin and solder, and its content is 0.1
If the content is less than 5.0%, this effect will be small, and if the content exceeds 5.0%, the solderability will deteriorate. Therefore, the Zn content is set to 0.1 to 5.0%. Mg, Cr, Ti, and Zr are all elements that improve hot workability, and if the content is less than 0.001%, this effect will be small, and if the content exceeds 0.01%, the hot workability will be reduced. The flowability deteriorates and the agglomeration yield decreases. Therefore, the Mg, Cr, Ti, and Zr contents are
Set to 0.001-0.01%. Furthermore, when two or more of Mg, Cr, Ti, and Zr are contained, the total content is set to 0.001 to 0.01% for the same reason as explained above. Furthermore, Sn is an essential element in the second aspect of the present invention, and Sn is an element that contributes to improving strength, stiffness strength, and repeated bendability, and if the content is less than 0.1%, these effects are small, and
If the content exceeds 2.0%, conductivity, heat resistance, and hot workability will be reduced. Therefore, the Sn content in the second invention is 0.1 to 2.0%. Next, the manufacturing method will be explained. This alloy is difficult to hot-roll, and if hot-rolled without applying the method described below, intergranular cracks will occur and the yield will decrease. As a result of investigating the above-mentioned causes, the inventor of the present invention found that the cause of the cracking is that during the process of heating the ingot to the hot rolling temperature, the alloy passes through the intermediate temperature brittle region shown in Figure 1. found that this is due to the embrittlement of grain boundaries due to residual stress in the ingot and thermal stress caused by heating. Furthermore, the susceptibility to this grain boundary embrittlement increases as the content of the intermetallic compound Ni ₂ Si in the ingot increases, and in the first invention, if the content is 0.1% or less, Su In the second invention including 0.08% or less, the residual stress of the magnitude that a normal ingot has will not cause grain boundary embrittlement that leads to cracking even if the ingot is heated under normal heating conditions. I discovered that. Next, in order to suppress the amount of Ni ₂ Si contained in the ingot to 0.1% in the first invention and 0.08% in the second invention, it is sufficient to increase the cooling rate during the ingot, and to change the material of the mold. Possible methods include using copper, which has good thermal conductivity, and reducing the thickness of the ingot to improve cooling. In addition, when considering cracks during hot rolling, cracks at the outer periphery of ordinary ingots become a problem. Therefore, it is important that the Ni ₂ Si content in the outer periphery is small. In other words, when the Ni ₂ Si content is high, Ni and Si precipitate in the form of intermetallic compounds Ni ₂ Si,
The strength within the grains is higher than when Ni and Si are in solid solution, and the stress concentration at the grain boundaries is greater. Furthermore, the relaxation of residual stress during heating is delayed. As a result of the above, grain boundary embrittlement is likely to occur. [Examples] Example 1 An alloy having the composition shown in Table 1 was melted in the atmosphere, and an ingot of 410 mmw x 150mmt x 3000mm was formed by semi-continuous casting. The casting conditions are shown in Table 2. This ingot was subjected to a hot rolling test at a temperature of 850°C to a thickness of 15 mm. The investigation results of the Ni ₂ Si content of the ingot and the hot rolling test results are shown in Table 2. The Ni ₂ Si content was determined by dissolving a sample taken from a position 20 mm from the outer periphery of the ingot with nitric acid (3 nitric acid to 1 part water), collecting the precipitated Ni ₂ Si as an undissolved residue with filter paper, and calculating the Ni 2 Si content. It was determined by measuring the weight. As shown in Table 2, Nos. 1, 2, and 3 are examples according to the first invention of the present invention, and the amount of Ni ₂ Si precipitated is 0.1%.
Since the following is true, cracks due to hot rolling will not be invented. In Table 2, Nos. 4, 5, and 6 are comparative examples with respect to the example of the first invention, and edge cracks occur during hot rolling because the amount of Ni ₂ Si precipitated exceeds 0.1%. [Example] Example 2 An alloy having the composition shown in Table 3 was melted in the atmosphere, and an ingot of 410 mmw x 150mmt x 3000mm was formed by semi-continuous casting. The casting conditions are shown in Table 4. This ingot was subjected to a hot rolling test at a temperature of 850°C to a thickness of 15 mm. Table 4 shows the results of the investigation of the Ni ₂ Si content of the castings and the results of the hot rolling test. The Ni ₂ Si content was determined by dissolving a sample taken from a position 20 mm from the outer periphery of the ingot in nitric acid (3 nitric acid to 1 part water), collecting the precipitated Ni ₂ Si as an undissolved residue with filter paper, and calculating the Ni 2 Si content. It was determined by measuring the weight. As shown in Table 4, Nos. 1, 2, and 3 are examples according to the second invention of the present invention, and the amount of Ni ₂ Si precipitated is
Since the content is 0.08% or less, no cracking occurs during hot rolling. In Table 4, Nos. 4, 5, and 6 are comparative examples with respect to the example of the second invention, and edge cracks occur during hot rolling because the amount of Ni ₂ Si precipitated exceeds 0.08%. [Effects of the Invention] As explained above, by the method for producing a copper alloy of the first invention according to the present invention, it is possible to produce a copper alloy for electrical/electronic components with high yield, which has both high strength and high conductivity. Also, the second method according to the present invention
The method for producing a copper alloy of the invention can produce an alloy for electrical/electronic parts that has both high conductivity and even higher strength at a high yield.

【表】【table】

【table】 [Brief explanation of drawings]

第１図は、本発明合金の試験片を各温度におい
て引張試験した時の伸びおよび引張強さを示した
ものである。 FIG. 1 shows the elongation and tensile strength of test pieces of the alloy of the present invention subjected to a tensile test at various temperatures.

Claims

[Claims] 1. In the manufacturing process of copper alloys for electrical and electronic parts, Ni: 1.0 to 3.5% (the same below weight%) Si: 0.2 to 3.5%
Contains 0.9%, Zn: 0.1-5.0%, Mg, Cr, Zr,
In the process of casting a molten alloy containing one or more of Ti at 0.001 to 0.01% and the balance consisting of Cu and unavoidable impurities, the amount of Ni ₂ Si compound precipitation on the ingot surface layer is suppressed to 0.1% or less. A method for producing a copper alloy for electrical/electronic parts, characterized by casting. 2 In the manufacturing process of copper alloys for electrical and electronic parts, Ni: 1.0 to 3.5%, Si: 0.2 to 0.9%, Zn: 0.1 to
Contains 5.0%, Sn: 0.1~2.0%, Mg, Cr, Zr,
In the process of casting a molten alloy containing one or more of Ti at 0.001 to 0.01% and the balance consisting of Cu and unavoidable impurities, the amount of Ni ₂ Si compound precipitation on the ingot surface layer is suppressed to 0.08% or less. A method for producing a copper alloy for electrical/electronic parts, characterized by casting.