JPS60131939A - Copper alloy for lead frame - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy for a lead frame for a semiconductor device with superior heat resistance, bendability and adhesive strength to plating by adding specified amounts of Ni, Sn, Al and P to Cu. CONSTITUTION:To Cu as a base are added 0.4-4.0wt% Ni, 0.5-5.0wt% Sn, 0.4-4.0wt% Al and <0.3wt% P, and they are alloyed. Fine compounds of Ni and Sn, Ni and Al, Ni and P, and Sn and P are precipitated, a deoxidizing effect is shown by P, and Ni, Sn and Al are solubilized in Cu, so a Cu alloy for a lead frame with superior strength, heat resistance, high adhesive strength to plating and solderability is obtd.

Description

【発明の詳細な説明】 本発明合金は半導体を要素とするＩＣｉ’、、ＬＳＩ等
の機器のリードフレーム用銅合金、特に耐熱性、曲げ加
工性およびメッキ密着性に優れた銅合金に関するもので
ある。[Detailed Description of the Invention] The alloy of the present invention relates to a copper alloy for lead frames of devices such as ICs, LSIs, etc. that use semiconductors as an element, and particularly relates to a copper alloy with excellent heat resistance, bending workability, and plating adhesion. be.

一般に半導体を要素とするＩＣＸＬＳＩ等の機器は何れ
も半導体ペレットリード、ボンディングワイヤにより構
成されたものをハーメチックシール、セラミックシール
技術により封止したものであり、種々の型式のものが使
用されている。In general, devices such as ICXLSI that use semiconductors as elements are constructed from semiconductor pellet leads and bonding wires and sealed using hermetic sealing or ceramic sealing technology, and various types are used.

而して従来これら機器のリードフレーム材としては鉄−
ニッケル系材料としてコバール（Ｆｅ　−２９％Ｎｉ−
１７チ００合金）、１４２合金、コバールに金を被覆し
たクラツド材、鉄−ニッケル合金にＵを被覆したクラツ
ド材、銅合金としてリン青銅、Ｃ１９４００（Ｃｉｕ−
Ｆａ−Ｚｎ−Ｐ合金）、１．９５００（Ｇｕ　−Ｆｅ　
−Ｇｏ　＝　Ｓｎ　−Ｐ合金）、０１１４１４１０（Ｃ
ｕ−Ｓｎ　−’　Ｐ合金）等が用いられている。しかし
ながら上記鉄−ニッケル系材料は耐熱性、強度は優れて
いるがコストが高いとともに、導電性が悪く、加工性も
悪−ため近時コストが安くかつ加工性、メッキ密着性お
よび半田付性が良好な銅系合金が主流を占めつつある。Traditionally, iron has been used as the lead frame material for these devices.
Kovar (Fe-29%Ni-
17chi00 alloy), 142 alloy, clad material made of Kovar coated with gold, clad material made of iron-nickel alloy coated with U, phosphor bronze as a copper alloy, C19400 (Ciu-
(Fa-Zn-P alloy), 1.9500 (Gu-Fe
-Go = Sn -P alloy), 01141410 (C
u-Sn-'P alloy), etc. are used. However, although the iron-nickel materials mentioned above have excellent heat resistance and strength, they are expensive, have poor conductivity, and have poor workability. Good copper-based alloys are becoming mainstream.

しかしながら上記の如き銅合金は耐熱性、電気（熱）的
特性、曲げ加工性等が劣るためリードフレーム材として
充分な特性を発揮することができないものであった。特
に最近のように高密度、高集積度が強く要求されるとこ
ろから高い導電率、強度、曲げ加工性および耐熱性を有
し、メッキ加工され易い表面品質を有する材料が必要と
なって来た。すなわち■高信頼性、■経済性、■サーマ
ルパフォーマンスといウモのが現在のリードフレーム材
への要求される条件となっているのである。However, the above-mentioned copper alloys have poor heat resistance, electrical (thermal) properties, bending workability, etc., and therefore cannot exhibit sufficient properties as a lead frame material. Particularly in recent years, where high density and high degree of integration are strongly required, materials with high conductivity, strength, bending workability, heat resistance, and surface quality that can be easily plated have become necessary. . In other words, the following conditions are required for current lead frame materials: ■High reliability, ■Economic efficiency, and ■Thermal performance.

メッキ加工され易い表面品質とは半導体ペレッ卜とリー
ドフレーム、ならびにボンディングワイヤとリードフレ
ームの接続性を向上し、リードフレームの耐酸化性、耐
腐食性、半田付性等を向上維持するだめに行なう金、銀
、ニッケル、スズ等のメッキ被着性が優れていることで
、このようなメッキ加工はリードフレームの如き材料に
おいては加工コスト中、大きな比重を占め品質信頼性に
大きく影響する。Surface quality that is easy to plate is to improve the connectivity between semiconductor pellets and lead frames, as well as bonding wires and lead frames, and to improve and maintain the oxidation resistance, corrosion resistance, solderability, etc. of lead frames. Due to the excellent adhesion of gold, silver, nickel, tin, etc., such plating processing accounts for a large percentage of the processing cost for materials such as lead frames, and has a large impact on quality reliability.

コバール、４２合金等の鉄−ニッケル系材料は導電性、
熱伝導性が劣るばかりか、メッキ加工が困難で特別の工
夫を必要とする。例えばこれ等基材の表面にニッケル層
とＳｎ　−Ｎｉ　合金層とを順次被着した後、該Ｓｎ　
−Ｎｉ　合金層上に銀層を被着するか、あるいは基材の
表面に銀および銅を含むシアンアルカリ性メッキ液にて
メッキを施し、その表面にメッキを行っている。一般に
リードフレーム材用銅合金として次の６項目を満足する
材料が強く要望されている。Iron-nickel materials such as Kovar and 42 alloy are conductive,
Not only does it have poor thermal conductivity, but plating is difficult and requires special ingenuity. For example, after sequentially depositing a nickel layer and a Sn-Ni alloy layer on the surface of these base materials, the Sn
-Ni A silver layer is deposited on the alloy layer, or the surface of the base material is plated with a cyan alkaline plating solution containing silver and copper, and the surface is plated. Generally, there is a strong demand for materials that satisfy the following six items as copper alloys for lead frame materials.

（１）電気および熱の伝導性が良いこと（２）耐熱性が
良いこと （５）曲げ加工性が良いこと （ＩＩ）強度が大きいこと （５）　メッキ密着性が良いこと （６）半田付性が良いこと 本発明はこれに鑑み種々研究の結果従来のり−器のリー
ドフレーム用鋼合金を開発したものでＮ１０、キー　４
．０　ｗｔ％（以下係と略記）ＳｎＯ，５’−５，０％
、ｈｔ　Ｏ，４−４，Ｏｆｙ、Ｆ’　０．３　％　以下
を含み残部がＧｕからなる合金に係る。即ち本発明合金
はＣｕ　を基材としＮｉ、Ｓｎ、　ｋｔ、　Ｐ　を添加
するものであり謳　＞　’Ｊ− ＮｉｘＳｎ１！、ＮｉｘＡ１ｇ％　ＮｉｘＰｇ　％　Ｓ
ｎｘ鴎等の金属間化合物を微小析出物として析出させる
こととＰの添加によって脱酸の効果を狙ったものであり
、さらにＣｕ基中にＮｉ、Ｓｎ　およびＡｔが固溶する
ことにより基材の強化をも狙ったもので銅合金としてこ
の従来の常識を越える強度、耐熱性を有し、良好なメッ
キ密着性、半田付性を有するリードフレーム用銅合金を
得たものである。(1) Good electrical and thermal conductivity (2) Good heat resistance (5) Good bending workability (II) High strength (5) Good plating adhesion (6) Solderability In view of this, the present invention has developed a steel alloy for the lead frame of a conventional glue machine as a result of various research.
．． 0 wt% (hereinafter abbreviated as "H") SnO, 5'-5,0%
, ht O, 4-4, Ofy, F' 0.3% or less, and the balance is Gu. That is, the alloy of the present invention has Cu as a base material and Ni, Sn, kt, and P are added thereto. , NixA1g% NixPg% S
The purpose is to precipitate intermetallic compounds such as NX as fine precipitates and to add P to achieve a deoxidizing effect.Furthermore, the solid solution of Ni, Sn, and At in the Cu base improves the deoxidizing effect of the base material. The aim was to provide a copper alloy for lead frames that has strength and heat resistance that exceed conventional wisdom as a copper alloy, and also has good plating adhesion and solderability.

餠して本発明合金においてＮｉ　Ｏ，４〜４０％、５ｎ
０５〜５０％ｋＡ　０キ〜キＯ％、Ｐ０′５％以下と限
定した理由はＮｉ　０１１％、ｓｎｏ、５％、ｈｔｏ、
キチ未満では必要とする強度、耐熱性が得られず、Ｎ１
４．０係、Ｓｎ　５．０％、Ａ４１．０％、Ｐ　０．３
　％　を越えると強度、耐熱性において優れた性能が得
られるが曲げ加工性が劣化するばかりでなく、メッキ密
着性および半田付性も劣化するからである。In the alloy of the present invention, NiO, 4-40%, 5n
05-50% kA 0-ki O%, P0' The reason for limiting it to 5% or less is Ni 011%, sno, 5%, hto,
If it is less than N1, the required strength and heat resistance cannot be obtained.
4.0 ratio, Sn 5.0%, A41.0%, P 0.3
%, excellent performance can be obtained in terms of strength and heat resistance, but not only bending workability deteriorates, but also plating adhesion and solderability deteriorate.

以下本発明合金を実施例によυ説明する。The alloy of the present invention will be explained below using examples.

る 黒鉛争つぼを使用してＯｕ　を溶解し、その湯面を木炭
粉末にて覆い十分溶解した後、Ｎｉ、Ｓｒ＋。After melting O using a graphite pot, covering the hot water surface with charcoal powder and thoroughly melting, Ni and Sr+ were dissolved.

Ａｔ１　Ｐの順に添加しこれを鋳造し第１表に示す組成
の幅１５０ｍｍ、長さ２００ｍｍ、厚さ２５咽の鋳塊を
得た次にこの鋳塊の表面を一面あだり２５咽面削した後
、熱間圧延を行ない、巾１５０諭厚さ８Ｍの板に冷間圧
延と焼鈍を繰シ返し加え最終圧延率１１０係にて厚さ０
．３　ｔｒｒｍの冷間圧延上がシ材を得た。これらの板
について曲げ加工性、導電率、引張り強さ、耐熱性、メ
ッキ密着性、半田付性を泪＋１宙１−た。これらの結果
を°第１表に示す。なお比較のために従来のリードフレ
ーム用合金についても同様な測定を行い、その結果を第
１表に併記した。At1 and P were added in this order, and this was cast to obtain an ingot with a width of 150 mm, a length of 200 mm, and a thickness of 25 mm with the composition shown in Table 1. Next, the surface of this ingot was ground by 25 mm per side. After that, hot rolling was carried out, and the plate with a width of 150 mm and a thickness of 8 mm was repeatedly cold rolled and annealed, and the final rolling rate was 110 mm to reduce the thickness to 0.
．． A material was obtained by cold rolling at 3 trrm. These plates were tested for bending workability, electrical conductivity, tensile strength, heat resistance, plating adhesion, and solderability. These results are shown in Table 1. For comparison, similar measurements were also performed on conventional lead frame alloys, and the results are also listed in Table 1.

曲げ加工性は板材より幅５咽、長さ５０朝の短冊型試験
片を切り出し、その中央部で１８０°密着曲げを行い、
該曲げ部の表面状態を観察し、割れ、しわの発生がなく
平滑なものを曲げ加工性が良いということでＯｕ、割れ
が明らかに発生しているものを曲げ加工性を不良という
ことで×印、その中間で割れ、しわがわずかに発生して
いるものをΔ印で表わした。The bending property was determined by cutting out a rectangular test piece with a width of 5 mm and a length of 50 mm from the plate material, and bending it closely at 180° at the center.
Observe the surface condition of the bent part, and if it is smooth with no cracks or wrinkles, it is judged as having good bending workability, and if it is smooth, it is judged as having good bending workability. mark, and those with cracks and slight wrinkles in the middle are indicated by Δ mark.

導電率および引張シ強さの測定はＪＩＳ−）＋０５０５
およびＪＩＳ−２２２４１に基づいて行った。Measurement of electrical conductivity and tensile strength is JIS-)+0505
and JIS-22241.

メッキ密着性は上記板の鈍し材についてリードフレーム
のメッキ工程と同様にアルカリ脱脂（１分間）−２０チ
硝酸工、チング（５０秒）−４５０℃加熱（５分間）−
５５０℃加熱（５分間）を行い、５５０℃、５分間加熱
で全く膨れの見られないものをＯｕ、１Ｉ５０℃、５分
間加熱では膨れは見られないが５５０℃、５分間加熱で
膨れが発生するものをΔ印、４５０℃、５分間加熱です
でに膨れが発生したものをｘ印で示しだ。Plating adhesion was determined using the same method as the lead frame plating process for the dull material of the above board: alkaline degreasing (1 minute), nitric acid treatment (50 seconds), heating at 450°C (5 minutes).
Heating at 550℃ for 5 minutes shows no swelling at 550℃ for 5 minutes. The ones that have already swelled after heating at 450°C for 5 minutes are marked with an x.

半田付性は垂直式浸漬法によシ２３０℃の５ｎｙ４ｏ％
ｐｂ共晶半田浴に１０秒間浸漬したものの表面を観察し
、その結果表面が滑らかなものを○印、表面に少し凹凸
が見えるものをΔ印、表面に凹凸が生じ半田が濡れてい
ない部分を生じているものをＸ印で示した。Solderability is 5ny4o% at 230℃ by vertical dipping method.
Observe the surface of the product immersed in the Pb eutectic solder bath for 10 seconds. As a result, the smooth surface is marked with ○, the surface with slight irregularities is marked with Δ, and the surface is uneven and the solder is not wet. What is occurring is indicated by an X mark.

耐熱性は前記圧−延材よりＪＩＳ−Ｚ２２０１　に規定
する引張り試験片を切り出し、これをアルコ゛ン雰囲気
中でＵＯＯ℃、５分間加熱焼鈍した後、引張り試験を行
い、その引張り強さを焼鈍前と比較し、強度の低下率が
５０％以下のものを耐熱性良好として○印、５０′％を
越えるものを耐熱性不良としてＸ印で表わした。The heat resistance was determined by cutting out a tensile test piece specified in JIS-Z2201 from the rolled material, annealing it at UOO°C for 5 minutes in an alcohol atmosphere, then performing a tensile test, and comparing the tensile strength with that before annealing. In comparison, those whose strength reduction rate was 50% or less were marked with a circle, indicating good heat resistance, and those whose strength decreased by more than 50% were marked with an X, indicating poor heat resistance.

第１表 第１表から明らかな如く本発明合金Ｎα１〜１ヰは導電
率１２〜６１％ｌＡＣ３、引張り強さ５６〜７５Ｋｆｆ
／−の特性を示し、良好な曲げ加工性と耐熱性を有して
おり、Ｃｕ−Ｆｅ　−Ｚｎ　−Ｐ合金に匹敵する導電率
とはるかに優れた引張り強度、耐熱性を有していること
がわかる。他にメッキ密着性、半田付性もＧｕ　−Ｚｎ
　−Ｐ合金に比べ十分優れているのがわかる。Table 1 As is clear from Table 1, the alloys Nα1 to 1 of the present invention have a conductivity of 12 to 61% lAC3 and a tensile strength of 56 to 75 Kff.
/- characteristics, has good bending workability and heat resistance, and has electrical conductivity comparable to Cu-Fe-Zn-P alloy and far superior tensile strength and heat resistance. I understand. In addition, Gu-Zn has good plating adhesion and solderability.
It can be seen that this is sufficiently superior to the -P alloy.

これに対してＮ１　の少ない比較合金１４０２１は引張
り強度および耐熱性が十分でなく曲げ加工性も若干劣り
、Ｎ１の多い比較合金Ｎ（１２５は導電率が低いばかり
でなく、曲げ加工性も悪く、メッキ密着性および半田付
性も劣っている。Ｓｎ　の少ない比較合金Ｎα２０は引
張り強度および耐熱性が十分でなく、曲げ加工性も若干
劣り、Ｓｎ　の多い比較合金Ｎ［Ｌ２６は導電率が低い
ばかりでなく、曲げ加工性も悪く、メッキ密着性および
半田付性も劣っている。Ａｔの少ない比較合金Ｎα１９
は引張シ強度および耐熱性が十分でなく、曲げ加工性も
若干／に：ｈ　Ａ　／　／７’ｌ　’Ｘ　１八Ｗｒ　Ｌ
ｍ　、会４仝Ｎｎ　２７　糾道’Ｉｔ　”Ｊｆｌ　−ｈ
：　（Ｆ’ｒ　層ばかりでなく、曲げ加工性も悪く、メ
ッキ密着性および半田付性も劣っている。Ｐの多い比較
合金Ｎα１５はメッキ密着性および半田付性が劣ってい
る。Ｎ１とＳｎ　の少ない比較合金Ｎα１８は引張り強
度および耐熱性が十分でない。On the other hand, comparative alloy 14021, which has less N1, has insufficient tensile strength and heat resistance and is slightly inferior in bending workability, while comparative alloy N (125), which has more N1, not only has low conductivity but also has poor bending workability. Plating adhesion and solderability are also poor. Comparative alloy Nα20, which has a low Sn content, does not have sufficient tensile strength and heat resistance, and has slightly inferior bending workability, while comparative alloy N[L26, which has a high Sn content, has low conductivity. However, the bending workability is poor, and the plating adhesion and solderability are also poor. Comparative alloy Nα19 with less At
The tensile strength and heat resistance are insufficient, and the bending workability is also slightly lower: h A / /7'l 'X 18Wr L
m, meeting4仝Nn 27 糾道'It ”Jfl -h
: (Not only the F'r layer but also the bending workability is poor, and the plating adhesion and solderability are also poor. Comparative alloy Nα15 with a large amount of P has poor plating adhesion and solderability.N1 and Sn Comparative alloy Nα18, which has a low tensile strength and heat resistance, does not have sufficient tensile strength and heat resistance.

Ｎ１とＳｎ　の多い比較合金Ｎ［Ｌ２２は導電率が低い
ばかりでなく、曲げ加工性も悪く、メッキ密着性および
半田付性も劣っている。Ｎ１とＡ４の少ない比較合金Ｎ
α１７は引張り強度および耐熱性が十分でない。Ｎ１と
Ａｔ　の多い比較合金Ｎａ２うけ導電率が低いばかりで
なく、曲げ加工性も悪く、メッキ密着性および半田付性
も劣っている。ＳｎとＡｔの少ない比較合金Ｎａ　１６
は引張り強度および耐熱性が十分でない。ＳｎとＡｔ　
の多い比較合金Ｎα２４は導電率が低いばかりでなく、
曲げ加工性も悪く、メッキ密着性および半田付性も劣っ
ている。Comparative alloy N[L22, which contains a large amount of N1 and Sn, not only has low conductivity, but also poor bending workability, and poor plating adhesion and solderability. Comparative alloy N with less N1 and A4
α17 has insufficient tensile strength and heat resistance. The comparative alloy Na2 containing a large amount of N1 and At not only has low electrical conductivity, but also poor bending workability, poor plating adhesion, and poor solderability. Comparative alloy Na 16 with less Sn and At
has insufficient tensile strength and heat resistance. Sn and At
Comparative alloy Nα24, which has a large amount of
The bending workability is poor, and the plating adhesion and solderability are also poor.

Claims (1)

【特許請求の範囲】[Claims] Ｎｉ０．４〜’Ｑ、　Ｏｗｔ％、Ｓζ０，５〜５．０　
ｗｔチ、Ｍ　Ｏ，キー　４．０　ｗｔ％、ＰＯ，’３ｗ
ｔ％以下を含み残部がＣｕからなることを特徴とするリ
ードフレーム用銅合金。Ni0.4~'Q, Owt%, Sζ0.5~5.0
wt Chi, M O, Key 4.0 wt%, PO, '3w
A copper alloy for lead frames, characterized in that it contains t% or less and the balance is Cu.