JPS6142772B2 - - Google Patents

Description

【発明の詳細な説明】[Detailed description of the invention]

本発明は、半導体リードフレーム材に要求され
る諸特性を具備した銅基合金に関する。 従来、半導体機器のリード材としては、素子お
よびセラミツクスとの接着および封止性の良好な
コバール合金（Fe―29Ni―16Co）や、42合金
（Fe42Ni）などの高ニツケル合金が好んで使用さ
れていた。しかし、近年の半導体回路の集積度の
増大に伴つて、熱放散性を一層改善する必要か
ら、さらにはコストダウンを図る面から、このと
ころリード材としては、銅基合金を使用する割合
が高まつている。 この従来のリード材用銅基合金としては、無酸
素銅、Sn入り銅、リン青銅、Fe入り銅などが知
られているが、いずれも一長一短があり、リード
材として必要とされる機械的強度、伸び、導電
性、熱放散性、耐軟化性、メツキ性、ハンダ付け
性、経済性などの諸条件を総合的にかつ十分に満
足すべく一層の改善がこの銅基合金に望まれてい
る。 本発明はこの要求を満たすことを目的としたも
のである。この目的において、本発明者らは試験
研究を重ねた結果、Ni：0.05〜0.40重量％、Fe：
0.5〜1.5重量％，Sn：0.5〜1.5重量％、を銅に含
有させた銅基合金がリードフレーム材として非常
に好適な諸性質を兼備することを見いだすことが
できた。そして、この銅基合金は、その製造にさ
いして、最終仕上げ圧延（冷間圧延）のさいに圧
延率を50％以上として必要板厚に仕上げ、その
後、250〜450℃の温度で５〜60分間の焼鈍を施す
ことによつて、リードフレーム材として１層良好
な特性を示すことがわかつた。 本発明のリードフレーム用銅基合金の諸特性は
後記実施例に示すとおりであるが、本銅基合金の
合金元素であるNi，FeおよびSnの含有量を前記
のように定めた理由の概要を説明するとつぎのと
おりである。 Niは、機械的強度、耐軟化性および耐蝕性を
改善する作用を供するが、0.05％未満ではこの効
果が得られない。しかし、0.4％を越えて含有さ
せると、後記表１のNo.９〜10に見られるように、
導電性とハンダ付け性が逆に劣化するようにな
る。 Feは、導電性を低下させることなく強度を向
上させる作用を供する。そして、固溶限以上の
Feの存在により、銅マトリツクス中に析出した
微細な鉄析出物が高温加熱時の結晶粒の粗大化を
阻止して耐軟化性を向上させる。Fe含有量が0.5
％未満では、後記表１のNo.５およびNo.６に見られ
るように、この強度と耐軟化性の改善効果が不十
分である。他方、Fe含有量が1.5％を越えると、
導電性が低下しまた加工性も悪くなる。 Snは、銅マドリツクス中に固溶して、強度と
耐軟化性を向上させる。しかし、Sn含有量が0.5
％未満では、表１のNo.７，No.８に見されるよう
に、強度と耐軟化性の改善効果が充分には現れな
い。他方、Sn含有量が1.5％を越えると、導電性
と熱伝導性が悪くなり、熱間加工性も害される。 このように、Ni：0.05〜0.40重量％、Fe：0.5
〜1.5重量％、Sn：0.5〜1.5重量％、を銅に含有
させることによつて本発明の銅基合金は半導体
IC用リード材に要求される諸特性を発現したも
のであるが、この銅基合金は、その粗板（冷延
板）を圧延率が50％以上のもとで仕上げ冷間圧延
し、ついで250〜450℃の温度で５〜60分間の焼鈍
を施すと、後記の表２に示すように、一層、リー
ド材として望ましい特性をもつ材料とすることが
できる。この場合、最後の仕上げ圧延率が50％未
満では、後続の焼鈍によつて充分な強度が得られ
ず、圧延率50％以上の仕上げ冷延と（250〜450
℃）×（５〜60分）の焼鈍との組合せが必要であ
る。焼鈍温度が250℃より低いと、また焼鈍時間
が５分より短いと伸びが充分ではなく、また焼鈍
温度が450℃より高いと、また焼鈍温度が60分よ
り長いと結晶粒が粗大化して耐軟化性が劣化する
とともに強度も充分なものではなくなる。 以下に代表的な実施例を挙げて本発明のリード
フレーム用銅基合金の特性を説明する。 実施例 １ 表１に示す成分組成の合金を高周波真空溶解炉
で溶製してこれを鋳造したインゴツトを850℃で
熱間圧延し、厚さ８mmの熱延板とした。この熱延
板を通常の酸洗処理した後、冷間圧延、焼鈍、酸
洗を繰り返し、最終的に50％の仕上げ冷間圧延に
より、厚さ0.5mmの冷延板を得た。この冷延状態
（最終焼鈍なし）の板からサンプルを採取して引
張試験により引張強度と伸びを測定すると共に、
導電率、耐軟化性、ハンダ性を測定した。なお、
熱伝導度は導電率と比例関係にあるので導電率の
測定で伝熱性を評価した。耐軟化性は、試料を30
分加熱後の硬度が加熱前の硬度（圧延状態の硬
度）の80％となるときの温度により評価した。ま
たハンダ付け性は、ハンダ拡がり試験法によつて
評価した。それらの結果を表１に総括して示し
た。 表１の結果からつぎのことが明らかである。 NiとSnの含有量は本発明範囲であつても、Fe
の含有量が本発明で規定する範囲より低い比較例
No.５，６は、強度、導電率および耐軟化性が十分
ではない。NiおよびFe含有量が本発明範囲であ
つてもSn含有量が本発明で規定する範囲より低
い比較例No.７，８は、強度と耐軟化性が充分では
ない。またFeおよびSnの含有量が本発明範囲で
あつてもNi含有量が本発明で規定する量より多
い比較例No.９，10は導電率とハンダ付け性が低下
している。さらにNiの含有量が本発明範囲であ
つてもFeとSnが本発明で規定する量より少ない
比較例No.11は耐軟化性およびハンダ付け性が劣つ
ている。 これに対し、本発明で規定する範囲のNi，Fe
およびSnを含有する本発明例No.１〜No.４はいず
れも強度、伸び、導電率（％IACS），耐軟化性お
よびハンダ性が良好である。 The present invention relates to a copper-based alloy having various properties required for semiconductor lead frame materials. Conventionally, high nickel alloys such as Kovar alloy (Fe-29Ni-16Co) and 42 alloy (Fe42Ni) have been preferred as lead materials for semiconductor devices because of their good adhesion and sealing properties with elements and ceramics. Ta. However, with the increase in the degree of integration of semiconductor circuits in recent years, there is a need to further improve heat dissipation, and in order to reduce costs, copper-based alloys are increasingly being used as lead materials. It is worshiped. Oxygen-free copper, Sn-containing copper, phosphor bronze, Fe-containing copper, etc. are known as conventional copper-based alloys for lead materials, but each has advantages and disadvantages, and the mechanical strength required for lead materials Further improvements are desired for this copper-based alloy in order to comprehensively and fully satisfy various conditions such as elongation, electrical conductivity, heat dissipation, softening resistance, plating performance, solderability, and economic efficiency. . The present invention aims to meet this need. For this purpose, the present inventors conducted repeated test and research and found that Ni: 0.05 to 0.40% by weight, Fe:
It has been found that a copper-based alloy in which copper contains 0.5 to 1.5% by weight and Sn: 0.5 to 1.5% by weight has various properties that are very suitable as a lead frame material. During production, this copper-based alloy is finished to the required plate thickness at a rolling rate of 50% or more during final finish rolling (cold rolling), and then heated at a temperature of 250 to 450°C for 5 to 60°C. It was found that by annealing the material for a few minutes, it exhibited even better characteristics as a lead frame material. The various properties of the copper-based alloy for lead frames of the present invention are as shown in the examples below, and a summary of the reasons why the contents of Ni, Fe, and Sn, which are alloying elements of the present copper-based alloy, were determined as described above. The explanation is as follows. Ni provides the effect of improving mechanical strength, softening resistance, and corrosion resistance, but if it is less than 0.05%, this effect cannot be obtained. However, if the content exceeds 0.4%, as shown in Nos. 9 to 10 of Table 1 below,
The conductivity and solderability will deteriorate. Fe serves to improve strength without reducing conductivity. And above the solid solubility limit
Due to the presence of Fe, fine iron precipitates precipitated in the copper matrix prevent grain coarsening during high-temperature heating and improve softening resistance. Fe content is 0.5
If it is less than %, the effect of improving strength and softening resistance is insufficient, as seen in Nos. 5 and 6 of Table 1 below. On the other hand, when the Fe content exceeds 1.5%,
The conductivity decreases and the processability also deteriorates. Sn forms a solid solution in the copper matrix to improve strength and softening resistance. However, the Sn content is 0.5
If it is less than %, as seen in No. 7 and No. 8 of Table 1, the effect of improving strength and softening resistance will not be sufficiently exhibited. On the other hand, if the Sn content exceeds 1.5%, electrical conductivity and thermal conductivity will deteriorate, and hot workability will also be impaired. Thus, Ni: 0.05-0.40 wt%, Fe: 0.5
~1.5% by weight and Sn: 0.5~1.5% by weight, the copper-based alloy of the present invention can be made into a semiconductor.
This copper-based alloy exhibits the various properties required for IC lead materials, and is produced by final cold-rolling the rough plate (cold-rolled plate) at a rolling rate of 50% or more, and then When annealing is performed at a temperature of 250 to 450°C for 5 to 60 minutes, the material can be made to have even more desirable properties as a lead material, as shown in Table 2 below. In this case, if the final finish rolling rate is less than 50%, sufficient strength cannot be obtained by the subsequent annealing, and if the final finish rolling rate is less than 50% (250~450
℃) × (5 to 60 minutes) is required in combination with annealing. If the annealing temperature is lower than 250°C or the annealing time is shorter than 5 minutes, the elongation will not be sufficient, and if the annealing temperature is higher than 450°C or longer than 60 minutes, the crystal grains will become coarse and the durability will deteriorate. As the softening property deteriorates, the strength also becomes insufficient. The characteristics of the copper-based alloy for lead frames of the present invention will be described below with reference to typical examples. Example 1 An alloy having the composition shown in Table 1 was melted in a high-frequency vacuum melting furnace, and an ingot was cast and hot-rolled at 850°C to form a hot-rolled plate with a thickness of 8 mm. After this hot-rolled sheet was subjected to ordinary pickling treatment, cold rolling, annealing, and pickling were repeated, and finally, a cold-rolled sheet with a thickness of 0.5 mm was obtained by 50% finish cold rolling. Samples were taken from this cold-rolled plate (without final annealing) and the tensile strength and elongation were measured by a tensile test.
Conductivity, softening resistance, and solderability were measured. In addition,
Since thermal conductivity has a proportional relationship with electrical conductivity, heat transfer was evaluated by measuring electrical conductivity. Softening resistance of sample 30
Evaluation was made based on the temperature at which the hardness after heating for 1 minute was 80% of the hardness before heating (hardness in rolled state). Moreover, solderability was evaluated by a solder spread test method. The results are summarized in Table 1. The following is clear from the results in Table 1. Even if the content of Ni and Sn is within the range of the present invention, Fe
Comparative example in which the content of is lower than the range specified by the present invention
Nos. 5 and 6 did not have sufficient strength, electrical conductivity, and softening resistance. Comparative Examples Nos. 7 and 8, in which the Ni and Fe contents were within the range of the present invention but the Sn content was lower than the range specified by the present invention, did not have sufficient strength and softening resistance. Further, even though the content of Fe and Sn was within the range of the present invention, the conductivity and solderability of Comparative Examples Nos. 9 and 10, in which the Ni content was greater than the amount specified by the present invention, were decreased. Furthermore, even though the Ni content is within the range of the present invention, Comparative Example No. 11, in which Fe and Sn are smaller than the amounts specified by the present invention, has poor softening resistance and solderability. On the other hand, Ni, Fe within the range specified in the present invention
Inventive examples No. 1 to No. 4 containing Sn and Sn are all good in strength, elongation, electrical conductivity (%IACS), softening resistance, and solderability.

【表】 実施例 ２ 実施例１のNo.４，No.５およびNo.10の合金につい
て、最終板厚に仕上げる最終冷延において表２に
表示の最終圧延率のもので0.25mmの板厚に冷間圧
延し、ついで表２に表示の焼鈍条件で最終焼鈍し
た場合（またはしなかつた場合）について、各試
料を採取して引張試験値と導電率を測定した。そ
の結果を表２に示した。[Table] Example 2 For alloys No. 4, No. 5, and No. 10 of Example 1, in the final cold rolling to final plate thickness, the plate thickness was 0.25 mm at the final rolling rate shown in Table 2. Each sample was cold rolled and then final annealed under the annealing conditions shown in Table 2 (or not), and the tensile test value and electrical conductivity were measured. The results are shown in Table 2.

【表】 表２の結果より、本発明合金は、最終加工率を
50％以上として適切な最終焼鈍を施すと高い強度
と伸びが得られることがわかる。例えば試験No.Ｄ
に見られるように、適切な最終圧下率と焼鈍条件
の組合せにより、実施例１の圧延まま（最終圧延
率50％）に比べて強度と伸びの両面での向上を図
ることができる。これに対して比較合金の場合に
は、この最終圧下率と焼鈍条件の組合せによつて
も強度の向上効果が低い。[Table] From the results in Table 2, the alloy of the present invention has a final processing rate of
It can be seen that high strength and elongation can be obtained by applying an appropriate final annealing with a content of 50% or more. For example, test No.D
As can be seen, by combining an appropriate final rolling reduction and annealing conditions, it is possible to improve both strength and elongation compared to the as-rolled material of Example 1 (final rolling ratio 50%). On the other hand, in the case of comparative alloys, the effect of improving strength is low even with the combination of this final rolling reduction and annealing conditions.

Claims (1)

【特許請求の範囲】 １ Ni：0.05〜0.40重量％，Fe：0.5〜1.5重量
％，Sn：0.5〜1.5重量％、残部がCuおよび不可
避的不純物からなるリードフレーム用銅基合金。 ２ Ni：0.05〜0.40重量％，Fe：0.5〜1.5重量
％，Sn：0.5〜1.5重量％，残部がCuおよび不可
避的不純物からなる銅基合金の粗板を、圧延率が
50％以上のもとで仕上げ冷間圧延し、ついで250
〜450℃の温度で５〜60分間の焼鈍を施すことか
らなるリードフレーム用銅基合金の製造法。[Claims] 1. A copper-based alloy for a lead frame, consisting of Ni: 0.05 to 0.40% by weight, Fe: 0.5 to 1.5% by weight, Sn: 0.5 to 1.5% by weight, and the balance being Cu and inevitable impurities. 2 A rough plate of a copper-based alloy consisting of Ni: 0.05 to 0.40% by weight, Fe: 0.5 to 1.5% by weight, Sn: 0.5 to 1.5% by weight, the balance being Cu and unavoidable impurities, was rolled at a rolling rate of
Finish cold rolling at 50% or more, then 250%
A method for manufacturing a copper-based alloy for lead frames, comprising annealing at a temperature of ~450°C for 5 to 60 minutes.