JP4703835B2 - Under bump metal, bump for semiconductor device, semiconductor device with conductive ball - Google Patents

Under bump metal, bump for semiconductor device, semiconductor device with conductive ball Download PDF

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JP4703835B2
JP4703835B2 JP2000342798A JP2000342798A JP4703835B2 JP 4703835 B2 JP4703835 B2 JP 4703835B2 JP 2000342798 A JP2000342798 A JP 2000342798A JP 2000342798 A JP2000342798 A JP 2000342798A JP 4703835 B2 JP4703835 B2 JP 4703835B2
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semiconductor device
bump
ball
conductive
bump metal
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JP2002151537A (en
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幸弘 山本
宏平 巽
英児 橋野
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Nippon Steel Chemical and Materials Co Ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02Bonding areas; Manufacturing methods related thereto
    • H01L2224/0212Auxiliary members for bonding areas, e.g. spacers
    • H01L2224/02122Auxiliary members for bonding areas, e.g. spacers being formed on the semiconductor or solid-state body
    • H01L2224/02123Auxiliary members for bonding areas, e.g. spacers being formed on the semiconductor or solid-state body inside the bonding area
    • H01L2224/02125Reinforcing structures
    • H01L2224/02126Collar structures
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02Bonding areas; Manufacturing methods related thereto
    • H01L2224/04Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/0401Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02Bonding areas; Manufacturing methods related thereto
    • H01L2224/04Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554External layer
    • H01L2224/05541Structure
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02Bonding areas; Manufacturing methods related thereto
    • H01L2224/04Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554External layer
    • H01L2224/0556Disposition
    • H01L2224/05568Disposition the whole external layer protruding from the surface
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/1012Auxiliary members for bump connectors, e.g. spacers
    • H01L2224/10122Auxiliary members for bump connectors, e.g. spacers being formed on the semiconductor or solid-state body to be connected
    • H01L2224/10125Reinforcing structures
    • H01L2224/10126Bump collar
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/12Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001Core members of the bump connector
    • H01L2224/13005Structure
    • H01L2224/13006Bump connector larger than the underlying bonding area, e.g. than the under bump metallisation [UBM]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/12Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001Core members of the bump connector
    • H01L2224/1302Disposition
    • H01L2224/13023Disposition the whole bump connector protruding from the surface
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001Technical content checked by a classifier
    • H01L2924/0002Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
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    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/013Alloys
    • H01L2924/0132Binary Alloys
    • H01L2924/01322Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases

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Description

【0001】
【発明の属する技術分野】
本発明は、半導体素子をフリップチップ方式やフィルムキャリア方式などのワイヤレスボンディング方式を用いて実装する場合に必要な、半導体素子のアンダーバンプメタルまたはバンプ形成方法、及びそれを有する半導体装置に関するものである。
【0002】
【従来の技術】
シリコンウェハのアルミニウム電極上にウェット方法でアンダーバンプメタル(UBM)あるいは突起電極(バンプ)を無電解メッキ法で形成する方法は、(1)ウェハ上のアルミニウム薄膜電極にジンケート処理によりアルミニウムと亜鉛とを置換する処理を行った後、無電解ニッケルメッキでUBMまたはバンプを形成する方法(Proceedings of IEEE Multi-Chip Module Conference MCMC-93,Santa Cruz 74 1993, Electronic Components and Technology Conference 412 1990, ISHM 1993 Proceedings 439ページ、信技報 CPM87−37 13ページ)と、(2)アルミニウム電極表面をパラジウムにより活性化させた後、無電解ニッケルメッキを行う方法(Proceedings of IEEE Multi-Chip Module Conference MCMC-93,Santa Cruz 74 1993, 信技報 CPM87−40)と、(3)アルミニウムとニッケルを直接置換させ、自己触媒型無電解ニッケルメッキを行う方法(SHM会誌 10巻、2号、21ページ)が用いられている。
【0003】
以下に一般に行われるUBMやバンプ作成法のうち上記(1)の方法を説明する。通常のフォトリソプロセスを経て作成されたアルミニウム電極付きシリコン基板を図1(a)に示す。図1(a)のアルミニウム電極付シリコン基板を酸性液(硫酸、硝酸、リン酸あるいはそれらの混合液)またはアルカリ性液(水酸化ナトリウム水溶液または水酸化カリウム水溶液)でライトエッチングを行う。次に酸性あるいはアルカリ性のジンケート(亜鉛)処理液で表面のアルミニウムの一部を亜鉛に換える(図1(b))。アルミニウム電極の凸凹が大きい場合は酸洗し再度ジンケート処理を行う。2度3度この処理を繰り返す場合もある。無電解ニッケルメッキ(図1(c))、さらに適宜無電解金メッキ(図1(d))を行い、UBMやバンプを作製する。
図2(b)及び図3(b)には、さらにUBM上にハンダボールを搭載しリフローすることにより、ハンダバンプを形成したものを示している。
銅電極表面へのニッケルバンプ形成も類似の方法で処理が行われる。
【0004】
【発明が解決しようとする課題】
しかしながら、ジンケート処理やパラジウム処理を行う前の前処理を十分に行っておかないと、ジンケート処理やパラジウム処理時に、電極上でのアルミニウムと亜鉛やパラジウムとの置換反応の速度あるいは銅とパラジウムとの置換反応の速度が、一個の電極内,チップ上の個々の電極間,ウェハ上でのチップ間,あるいは同時処理するウェハ間で異なるという事態が生じ易い。この現象は、次工程の無電解ニッケルメッキ工程や、場合により行われる酸洗工程,2回目以降のジンケート処理工程の均一性に影響し、ニッケルメッキ層の厚みや密着性に差を生じさせていた。はなはだしい場合には、ニッケルが全くメッキ膜として生成しない事態も起きていた。この為に出来上がったUBMやバンプの高さにバラツキや表面の凹凸に差が出たりして、半導体装置として使用出来ないものが出来たりしていた。この原因としては、ウェハやチップ取り扱い時における小さなゴミや油分や水分が考えられる。したがって、それらの不均一状態を取り除き、全てのアルミニウムや銅の電極部分が小さなゴミや油分や水分等の無い均一な面となるように前処理を十分に行う必要がある。
【0005】
これまではアルカリ脱脂や酸エッチング等が行われてきたが、不十分であったり、アルカリ脱脂時に電極金属が溶けてしまったりした。また、プラズマエッチングも行われた例があるが、真空装置が必要であり、コスト高である。
【0006】
本発明は、上記問題点を除去し、ウェットプロセスによりUBMやバンプを形成する際に、一個の電極内の各部分,チップ上の個々の電極間,ウェハ内でのチップ間,異なるウェハ間での電極上のニッケル膜厚及び密着性の差を出来るだけ小さくし、均一で信頼性に優れたUBMやバンプを形成する方法を提供することを目的とする。またそのようにして作製されたUBM上に均一で信頼性に優れた金属バンプを付けた半導体装置を提供することを目的とする。
【0007】
【課題を解決するための手段】
本発明は、上記目的を達成するために、以下のような手段を用いる。
(1)半導体素子の電極上に金属メッキにより形成したアンダーバンプメタルであって、中央部分が凹み外周部分がせり上がった形状であり、外周部分が中央部分より厚い部分を有することを特徴とするアンダーバンプメタル。
(2)(1)記載のアンダーバンプメタル上に、導電性ボールを搭載後、接着またはリフローして形成したものである特徴とする半導体装置用バンプ。
(3)前記導電性ボールが、該導電性ボールの粒径を 2rとし、各アンダーバンプメタルのメッキパッドの面積をS1とした時、
(S1/π)3/2 < 2(r3 ) (式1)
を満たす粒径2rの導電性ボールであることを特徴とする(2)記載の半導体装置用バンプ。
(4)前記導電性ボールが、該導電性ボールの粒径と使用する導電性ボールの平均粒径2rm との差を△rとした時、個々のボールが
| △r|/2rm < 0.05 (式2)
である条件を満たす導電性ボールであって、前記アンダーバンプメタルが、各アンダーバンプメタルパッドの表面積をS1とし、 Smを全アンダーバンプメタルパッドの平均の面積とした時、
0 < |{S1− Sm}|/Sm < 0.1 (式3)
である条件を満たすアンダーバンプメタルであることを特徴とする(2)又は(3)に記載の半導体装置用バンプ。
(5)(2)乃至(4)のいずれかに記載の半導体装置用バンプを有する半導体装置であって、アンダーバンプメタル上に搭載し接合した導電性ボールの頂上からアンダーバンプメタルの中心部への断面におけるボールの横方向の最大長さをd、縦方向のボールの高さをcとし、ボール断面でdとcの交点から上の部分をaとし、交点の下の部分をbとした時、0.5 ≦ c/d <1かつ、0 ≦b/a < 1 となることを特徴とする導電性ボール付半導体装置。
(6)(2)乃至(4)のいずれかに記載の半導体装置用バンプを有する半導体装置におけるアンダーバンプメタル上に接合された導電性ボールに、更に他の電極が接合され、前記のアンダーバンプメタルの面積をSとし、導電性ボールの接合後の高さをhとした時、
S < 4πh2 (式4)
となることを特徴とする導電性ボール付半導体装置
【0008】
【発明の実施の形態】
以下、本発明の実施の形態について図面に基づいて詳細に説明する。
図1を用いて本発明におけるアルミニウム電極上へのUBM及びバンプ形成法を例に説明する。
【0009】
図1(a)に、アルミニウム電極をパターニングしたシリコン基板(アルミニウム電極の厚みは例えば 0.5〜2μm)を示す。表面清浄化処理としての以下の2工程を行う。
【0010】
第一に、少なくとも1回以上有機溶媒中でウェハまたはチップ等の電極表面を洗浄する工程を導入する。有機溶媒中の洗浄はそれぞれ1〜30分とし、超音波をかけても良い。この処理工程は、1分以下では効果が乏しく、30分以上行っても効果は同じである。有機溶媒としては、例えばアセトンやメチルエチルケトン等のケトン系のもの、エタノールやメタノールやプロパノール等のアルコール系のもの、あるいはそれらを適当な比率で混合した混合物を用いる。その他テトラヒドロフラン等ウェハ上に付着したごみ・油分・水分を溶かすまたは流し去る各種の溶媒を使用しても良い。複数回洗浄を行う時は、溶媒として比誘電率の低いものと高いもののように、比誘電率の異なるものを選択するのが良い。
【0011】
洗浄が不十分の場合は、第二に、前記有機溶媒を乾燥後、さらにUVオゾン洗浄を行い、ウェハまたはチップ等の電極上の有機物を完全に除去する工程を導入する。これは、大気中または酸素雰囲気中または酸素をわずかでも含む雰囲気中で紫外線を1分〜30分間当てることにより、有機物を分解除去する工程である。この処理工程は、1分以下では効果が乏しく、30分以上行っても効果は同じである。ここでいうUVオゾン洗浄とは、電極表面に酸素の存在下でUV(紫外)光を当て、紫外線及び紫外線により発生したオゾンで有機物を分解洗浄する工程である。
【0012】
以上の処理により金属電極上の無機物及び有機物は全て除去される。この工程はメッキの脱脂処理前に行うことが好ましい。上記処理後は通常の前処理をしてメッキ処理を行う。一例を下記に示す。
【0013】
酸性液またはアルカリ性液でライトエッチングを行う。酸性液は主として希硫酸液が用いられる。リン酸や硝酸を含んでいても良い。硫酸の濃度は10〜60%のものを使用する。界面活性剤を含んでいても良い。あるいは、有機酸を含んでいても良い。アルカリ性の液の場合は、1〜50%の水酸化ナトリウムや水酸化カリウム水溶液が用いられる。次にジンケート(亜鉛)処理液またはパラジウム処理液で表面のアルミニウムの一部を亜鉛またはパラジウムに換える(図1(b))。本発明において、ジンケート処理とは亜鉛に置換する処理のことをいう。一度亜鉛またはパラジウム置換したものを酸洗し再びジンケート処理またはパラジウム処理する工程を1回以上行って、より平滑性に優れた表面を得ることも出来る。一般にこのジンケート処理液は、アルカリ性のものが使用されるが、pHが10以上である場合が多く、アルミ電極のロットによっては均一な表面が得られないことがある。この際には、アルカリ強度の低い処理液を使用したり、酸性の処理液を使用したり、複数回のジンケート処理の場合は濃度の異なるものや液性の異なる処理液を使用して均一な処理面とする。この後、無電解ニッケルメッキ、適宜無電解金メッキを順次行い、UBMやバンプを作成する。無電解ニッケルメッキ液としては、Ni-P系のメッキ液やNi-B系メッキ液を使用することが出来る。ジンケート処理液・無電解ニッケルメッキ液・無電解金メッキ液は、一般書、例えば、{「無電解めっき」 神戸徳蔵著 槇書店 1984年刊 } を参考にメッキ液を作成して使用しても良い。金メッキは必要に応じて行う。
【0014】
Ni-Pメッキの際に錯化剤を変えたり、ニッケル濃度を高く変えることにより、電極パッドの中央部が凹んだ形状のUBMを作製することが出来る。酸性のメッキ液を用いる条件では、ニッケルの濃度を例えば3.4g/l以上にしたメッキ液を用いる等の手段を行えば、上記形状のUBMを形成することが出来る。この形状のUBMを使用した場合はマウンターにより導電性ボールを搭載した時に、ボールが転がったりせず、バンプの信頼性を向上させることが出来る。図4及び図5に電極パッドの中央部が凹んだ形状のUBMの模式図を示す。電極パッドの中央部が凹んだ形状のUBMを使用した場合、ボール高さ・シェア強度とも表面が平坦なものと同様の値が得られる。
銅電極の場合もアルミニウム電極とほぼ同様の処理を行えば良い。
【0015】
図3 (b)には、上記手法で作成したUBM上に、導電性ボールとして半田ボールを搭載し、リフローすることにより、半田バンプを形成したものを示している。半田は共晶半田,各種鉛フリー半田,コアが銅で周囲が半田のボール等を使用することが出来る。
【0016】
図2、3及び6を用いて本発明におけるUBMを使用しバンプを形成する方法、及びバンプ形成した半導体装置について説明する。
半田ボールを搭載するニッケルあるいはニッケル金メッキのUBMにおいて、半田ボールとUBMの接合面は、図2(a)と図3(a)の部分9で示す様な形状をしており、UBMの大きさと同じ大きさである。ここで、使用する導電性ボールの粒径を 2r とし、UBMのニッケルあるいはニッケル金メッキパッドの面積をS1とした時、(式1) の条件を満たす粒径2rの導電性ボールを使用することにより、金属ボールをUBM上に接続した際に、半導体素子における接着した導電性ボールの縦断面形状が、少なくとも半球状(図2の (a)及び(b))より大きい形状(例えば図3の (a)及び(b))となり、半導体装置として使用する際に密着性の良いボンデングが行える。それより小さい場合は平坦なバンプ形状となり、密着性の良いチップとして使用しにくくなる。
【0017】
UBM上に導電性ボールを接続させる際に、使用する平均直径2rmの導電性ボールの平均値からのずれを△rとした時、個々のボールが、(式2)の条件を満たす導電性ボールを使用することにより導電性バンプを形成すれば、高さの揃ったバンプが得られ、半導体装置として使用する際に密着性の良いボンデングが行える。0.05より大きいとバンプ高さのバラツキのため、接合不良が出やすくなる。さらに、各UBMパッドの表面積をS1とし、 Smを全UBMパッドの平均の面積とした時、(式3)の条件を満たすUBMを使用することにより導電性バンプを形成すれば、高さの揃ったバンプが得られ、半導体素子として使用する際に密着性の良いボンデングが行える。0.1より大きい時はボール搭載後にバンプ高さのバラツキのために、接合不良が出やすくなる。
【0018】
バンプ形成の際に、導電性ボールをUBM上に搭載し接合した後に、図6に示すようにボールの頂上からUBMの中心部への断面において、ボールの横方向の最大長さをd、縦方向のボールの高さをcとし、ボールのdとcの交点から上の部分をaとし、交点の下の部分をbとした時、0.5 ≦ c/d < 1かつ、0 ≦b/a < 1 となるように導電性ボールを付けた半導体装置とする。c/dが0.5より小さいと接続後のボールは半球状より小さくなり、ボンデイングし難くなる。c/dが1より大きいと密着性の良い接合が得られない。b/aが0の場合は接続後のボールが半球状であり、b/aが1以上では密着性が悪く好ましくない。
【0019】
作製したUBM上に導電性ボールが搭載または接合されている半導体装置において、バンプを使用してボンデイングする際に、そのアンダーバンプメタルの面積をSとし、導電性ボールの接合後の高さをhとした時、(式4)を満たすように導電性ボールを付けると密着性に優れた半導体装置が得られる。S=πh2で半球状のまま接合する状態であり、S > 4πh2では、接合性が悪くなる。
銅電極の場合にも同様なプロセスで処理を行い、半導体装置が得られる。
【0020】
本方法によれば、均一な高さとシェア強度をもつUBMやバンプを形成することが出来る。またUBM上にハンダボールを搭載し、リフローすれば、密着性の良い均一な高さの信頼性の高いハンダバンプを形成することが出来、それによる半導体装置が得られる。ハンダボール使用の場合にはチップやウェハの希望の位置にハンダバンプを形成することも出来る。作成したバンプのシェア強度試験においても均一な値が得られる。
【0021】
【実施例】
以下に本発明を実施例を用いて説明する。処理条件等はこれら実施例のみにとらわれるものではない。
【0022】
参考例1)
図1(a)に示すようなパターニングしたアルミニウム電極(厚さ1μm)の付いたチップ(周囲に100μm角のアルミニウム電極を持ち、80μm角で電極部分にアルミニウムが出ており、140μmピッチで全部で200ピンの電極がある。)を用いた。前処理としてアセトン中で5分、エタノール中で5分それぞれ超音波洗浄を行った。乾燥後、UVオゾン洗浄器で5分間洗浄処理を行った。その後、50%硫酸水溶液を用いて55℃で3分間エッチングする。水洗後、市販のジンケート処理液:サブスターAZ(奥野製薬製)を用いて25℃で120秒間亜鉛置換を行った。水洗後、無電解ニッケルメッキ液:トップケミアロイ66(奥野製薬製)を用いて、65℃で30分間ニッケルメッキを行った。ニッケルメッキ厚は5〜5.5μmであった。水洗後、無電解金メッキ液:フラッシュゴールドNB(奥野製薬製)を用いて90℃で15分間金メッキした。メッキ後のUBMの面積は平均値が952μm2であり、各々のUBMのパッド面積S1は、92.52〜97.52μm2であった。これは、各UBMパッドの表面積S1 と、全UBMパッドの平均の面積Smが(式3)条件を満たす。金メッキ厚は0.05μmであった。水洗後、乾燥した。UBMの高さは5〜5.5μmであった。
【0023】
100±2μmφの共晶ハンダボールを使用した。ここで使用したボール径の平均値は100μmであり、使用した個々の導電性ボールは98〜102μm以内に入っていた。これは、(式2)の条件を満たしている。
また、上記パッド面積と導電性ボールの粒径は、前記(式1)を満たす。
【0024】
そのボールを搭載し、リフローした。リフロー後、ハンダバンプのシェア強度を測定した。任意に測定した10個のシェア強度測定値を表1に示す。測定値にバラツキが少なく、十分な強度を持っている。またボール高さは、77.8 ± 1.5 μmであり、バラツキが2%以内になっていた。
【0025】
図6において、c/d=0.65〜0.66、b/a=0.45であった。また、このバンプを使用して80μm角の電極を持つチップにフリップチップボンデイングした際に、そのUBMの面積Sは、S = 92.52〜97.52μm2 、導電性ボールの接合後の高さhは、h=54μmとなり、 (式4) を満足していた。
【0026】
参考例2)
参考例1において、180秒間のジンケート処理の後水洗し、25%硝酸水溶液で30秒間酸洗処理を行い、水洗後、第二のジンケート処理を120秒間行う以外は、全て同様の条件でハンダバンプを作成した。その後、シェア強度の測定を行った。任意に測定した10個の測定値を表1に示す。測定値にバラツキが少ない。UBMの高さは、5〜5.5μmであった。ボール高さは、77.3±1.6μmであった。
図6において、c/d=0.65〜0.66、b/a=0.45であった。
【0027】
参考例3)
参考例1において、120秒間のジンケート処理の後水洗し、25%硝酸水溶液で30秒間酸洗処理を行い、水洗後、第二のジンケート処理を15秒間行う以外は、全て同様の条件でハンダバンプを作成した。その後、シェア強度の測定を行った。任意
に測定した10個の測定値を表1に示す。測定値にバラツキが少ない。UBMの高さは、5〜5.5μmであった。ボール高さは、77.3±1.6μmであった。
図6において、c/d=0.65〜0.66、b/a=0.45であった。
【0028】
(実施例4)
参考例1において、120秒間のジンケート処理の後水洗し、25%硝酸水溶液で15秒間酸洗処理を行い、水洗後、第二のジンケート処理を120秒間行い、無電解ニッケルメッキ液としてICPニコロン−USD(奥野製薬製:85℃で30分メッキ)を使用した以外は、全て同様の条件でハンダバンプを作成した。中央部が凹んだUBMが得られた。その後、シェア強度の測定を行った。任意に測定した10個の測定値を表1に示す。測定値にバラツキが少ない。UBMの高さは、5〜5.5μmであった。ボール高さは、77.2±1.7μmであった。
図6において、c/d=0.65〜0.66、b/a=0.45であった。
【0031】
(比較例)
前処理において有機溶媒洗浄とUVオゾン洗浄を行わない以外は、全て参考例1と同様の処理を行い、ハンダバンプを形成した。シェア強度の測定を行った。任意に測定した10個の測定値(シェア強度測定値(単位:gf/ピン))を表1に示す。測定値にバラツキが大きい。UMBの高さは、4.5〜5.5μmであり、ややバラツキが大きかった。ボール高さは、77.3±2.7μmで、バラツキが大きい。
【0032】
【表1】

Figure 0004703835
【0033】
【発明の効果】
以上、詳細に説明したように、本発明によれば、以下のような効果を奏することが出来る。本方法によれば、アルミニウムや銅の電極上に均一な高さのUBMやバンプを形成することが出来る。またUBM上にハンダボールを搭載し、リフローすれば、均一な高さのハンダバンプを形成することが出来る。また、この様にして均一高さのバンプを持つ信頼性のある半導体装置が得られる。
【図面の簡単な説明】
【図1】無電解メッキによるニッケル金のUBM作成を示す図であり、(a)はアルミ電極パターニング後、(b)はジンケート処理(亜鉛置換)またはパラジウム処理、(c)は無電解ニッケルメッキ、(d)は無電解金メッキを示す。
【図2】リフロー後のハンダボール形状差を示す図であり、(a)はUBMを上から見た所(小さいボール)、(b)はUBMを横から見た断面図(小さいボール)である。
【図3】リフロー後のハンダボール形状差を示す図であり、(a)はUBMを上から見た所(大きいボール)、(b)はUBMを横から見た断面図(大きいボール)である。
【図4】周辺の盛上った電極
【図5】周辺の盛上った電極(断面図)
【図6】 UBM上に半田ボールをリフローした断面図
【符号の説明】
1. SiO2酸化膜付シリコン基板
2. アルミニウム電極
3. 窒化珪素膜または酸化珪素膜(パッシベーション膜)
4. Zn膜
5. Ni-BまたはNi-P膜またはそれらの混合膜
6. Au膜
7. 半田ボール
8. 電極上のパッシベーション膜の外枠
9. UBM部分[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of forming an under bump metal or bump of a semiconductor element and a semiconductor device having the same, which are required when a semiconductor element is mounted using a wireless bonding method such as a flip chip method or a film carrier method. .
[0002]
[Prior art]
The method of forming an under bump metal (UBM) or bump electrode (bump) on an aluminum electrode of a silicon wafer by an electroless plating method is as follows. (1) Aluminum and zinc are formed by zincate treatment on an aluminum thin film electrode on the wafer. After performing the process of replacing UBM or bump by electroless nickel plating (Proceedings of IEEE Multi-Chip Module Conference MCMC-93, Santa Cruz 74 1993, Electronic Components and Technology Conference 412 1990, ISHM 1993 Proceedings Page 439, Technical Report CPM87-37, page 13), and (2) Method of performing electroless nickel plating after activating the aluminum electrode surface with palladium (Proceedings of IEEE Multi-Chip Module Conference MCMC-93, Santa Cruz 74 1993, IEICE CPM87-40), and (3) self-catalytic electroless nickel by directly replacing aluminum and nickel. Method of performing Rumekki (SHM Journal Vol. 10, No. 2, page 21) is used.
[0003]
Hereinafter, the method (1) will be described among UBM and bump forming methods generally used. FIG. 1 (a) shows a silicon substrate with an aluminum electrode prepared through a normal photolithography process. The silicon substrate with an aluminum electrode in FIG. 1A is light-etched with an acidic solution (sulfuric acid, nitric acid, phosphoric acid or a mixture thereof) or an alkaline solution (aqueous sodium hydroxide solution or aqueous potassium hydroxide solution). Next, a part of the surface aluminum is replaced with zinc by an acidic or alkaline zincate (zinc) treatment solution (FIG. 1B). When the unevenness of the aluminum electrode is large, it is pickled and subjected to zincate treatment again. This process may be repeated twice and three times. Electroless nickel plating (FIG. 1 (c)) and further electroless gold plating (FIG. 1 (d)) are performed to produce UBM and bumps.
FIG. 2B and FIG. 3B show a solder bump formed by mounting a solder ball on the UBM and performing reflow.
The nickel bump formation on the copper electrode surface is processed in a similar manner.
[0004]
[Problems to be solved by the invention]
However, if the pretreatment before the zincate treatment or palladium treatment is not sufficiently performed, the rate of the substitution reaction between aluminum and zinc or palladium on the electrode or the copper and palladium during the zincate treatment or palladium treatment. There is a tendency that the speed of the substitution reaction is different within one electrode, between individual electrodes on a chip, between chips on a wafer, or between simultaneously processed wafers. This phenomenon affects the uniformity of the next electroless nickel plating process, the pickling process performed in some cases, and the second and subsequent zincate treatment processes, and causes a difference in the thickness and adhesion of the nickel plating layer. It was. In extreme cases, there was a situation in which nickel was not produced as a plating film at all. As a result, the height of the completed UBM and bumps varied, and the unevenness of the surface appeared, making it impossible to use as a semiconductor device. Possible causes of this are small dust, oil, and moisture when handling wafers and chips. Therefore, it is necessary to sufficiently perform the pretreatment so that those non-uniform states are removed and all the aluminum and copper electrode portions have a uniform surface free from small dust, oil, moisture and the like.
[0005]
Until now, alkaline degreasing, acid etching, and the like have been performed, but it was insufficient or the electrode metal was melted during alkaline degreasing. Moreover, although there is an example in which plasma etching is also performed, a vacuum apparatus is necessary and the cost is high.
[0006]
The present invention eliminates the above-mentioned problems, and forms UBMs and bumps by a wet process. Each part in one electrode, between individual electrodes on a chip, between chips in a wafer, and between different wafers. An object of the present invention is to provide a method for forming a uniform and highly reliable UBM and bump by minimizing the difference in nickel film thickness and adhesion on the electrode. It is another object of the present invention to provide a semiconductor device in which uniform and highly reliable metal bumps are formed on the UBM thus manufactured.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention uses the following means.
(1) a under-bump metal formed by metal plating on the electrode of the semiconductor element, Ri shape der the central portion outer peripheral portion recessed rises auction, the Rukoto outer peripheral portion having a thicker portion than the central portion Characterized under bump metal.
(2) A bump for a semiconductor device, which is formed by bonding or reflowing a conductive ball on the under bump metal described in (1).
(3) when the conductive balls, the particle diameter of the conductive balls and 2r, the area of the plating pads of each under-bump metal was S 1,
(S 1 / π) 3/2 < 2 (r 3) ( Equation 1)
The bump for a semiconductor device according to (2), which is a conductive ball having a particle diameter of 2r satisfying
(4) the conductive balls, when the difference between the average particle diameter 2r m of the conductive balls to be used as the particle diameter of the conductive balls △ was r, individual balls
Δr | / 2r m <0.05 (Formula 2)
When the under bump metal has a surface area of each under bump metal pad as S 1 and S m is an average area of all under bump metal pads,
0 <| {S 1 - S m} | / S m <0.1 ( Equation 3)
The bump for a semiconductor device according to (2) or (3), wherein the bump is an under bump metal that satisfies the following condition.
(5) A semiconductor device having a bump for a semiconductor device according to any one of (2) to (4), from the top of a conductive ball mounted on and bonded to the under bump metal to the center of the under bump metal In the cross section, the maximum horizontal length of the ball is d, the vertical height of the ball is c, the upper part of the ball cross section from the intersection of d and c is a, and the lower part of the intersection is b. A semiconductor device with a conductive ball, wherein 0.5 ≦ c / d <1 and 0 ≦ b / a <1.
(6) Another electrode is further bonded to the conductive ball bonded on the under bump metal in the semiconductor device having the bump for a semiconductor device according to any one of (2) to (4), and the under bump described above. When the area of the metal is S and the height after joining the conductive balls is h,
S <4πh 2 (Formula 4)
A semiconductor device with a conductive ball .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A method for forming UBM and bumps on an aluminum electrode in the present invention will be described as an example with reference to FIG.
[0009]
FIG. 1A shows a silicon substrate on which an aluminum electrode is patterned (the thickness of the aluminum electrode is 0.5 to 2 μm, for example). The following two steps as the surface cleaning treatment are performed.
[0010]
First, a step of cleaning an electrode surface such as a wafer or a chip in an organic solvent at least once is introduced. Cleaning in the organic solvent may be performed for 1 to 30 minutes, and ultrasonic waves may be applied. This treatment step is less effective in less than 1 minute, and the effect is the same even if performed for more than 30 minutes. As the organic solvent, for example, a ketone type such as acetone or methyl ethyl ketone, an alcohol type such as ethanol, methanol or propanol, or a mixture obtained by mixing them at an appropriate ratio is used. In addition, various solvents such as tetrahydrofuran, which dissolves or removes dust, oil, and water adhering to the wafer may be used. When performing multiple times of washing, it is preferable to select solvents having different relative dielectric constants, such as those having a low and high relative dielectric constant.
[0011]
If the cleaning is insufficient, secondly, after drying the organic solvent, a UV ozone cleaning is further performed to completely remove organic substances on the electrode such as a wafer or a chip. This is a step of decomposing and removing organic substances by applying ultraviolet rays for 1 minute to 30 minutes in the air, in an oxygen atmosphere, or in an atmosphere containing a slight amount of oxygen. This treatment step is less effective in less than 1 minute, and the effect is the same even if performed for more than 30 minutes. The UV ozone cleaning here is a step in which UV (ultraviolet) light is applied to the electrode surface in the presence of oxygen, and organic substances are decomposed and cleaned with ultraviolet rays and ozone generated by the ultraviolet rays.
[0012]
By the above treatment, all inorganic substances and organic substances on the metal electrode are removed. This step is preferably performed before the degreasing treatment of plating. After the above-described treatment, a normal pretreatment is performed for the plating treatment. An example is shown below.
[0013]
Light etching is performed with an acidic solution or an alkaline solution. A dilute sulfuric acid solution is mainly used as the acidic solution. It may contain phosphoric acid or nitric acid. A sulfuric acid concentration of 10 to 60% is used. A surfactant may be included. Alternatively, it may contain an organic acid. In the case of an alkaline solution, 1 to 50% sodium hydroxide or potassium hydroxide aqueous solution is used. Next, a part of aluminum on the surface is replaced with zinc or palladium by a zincate (zinc) treatment solution or a palladium treatment solution (FIG. 1B). In the present invention, the zincate treatment refers to a treatment replacing zinc. It is also possible to obtain a surface with better smoothness by pickling zinc or palladium-substituted one and performing zincate treatment or palladium treatment once more or more. In general, an alkaline solution is used as the zincate treatment solution, but the pH is often 10 or more, and a uniform surface may not be obtained depending on the lot of aluminum electrodes. In this case, use a treatment solution with low alkali strength, use an acidic treatment solution, or use multiple treatment solutions with different concentrations or different liquidities in the case of multiple zincate treatments. The processing surface. Thereafter, electroless nickel plating and appropriate electroless gold plating are sequentially performed to create UBMs and bumps. As the electroless nickel plating solution, a Ni-P plating solution or a Ni-B plating solution can be used. The zincate treatment solution, electroless nickel plating solution, and electroless gold plating solution may be used by preparing a plating solution with reference to a general book, for example, {"Electroless plating" published by Tokuzo Kobe, published in 1984. Gold plating is performed as necessary.
[0014]
By changing the complexing agent during Ni-P plating or changing the nickel concentration high, UBMs with a recessed central part of the electrode pad can be produced. Under the condition using an acidic plating solution, the UBM having the above shape can be formed by using a plating solution with a nickel concentration of, for example, 3.4 g / l or more. When this shape of UBM is used, when the conductive ball is mounted by the mounter, the ball does not roll, and the reliability of the bump can be improved. 4 and 5 are schematic diagrams of UBMs having a recessed central portion of the electrode pad. When a UBM with a recessed center part of the electrode pad is used, the ball height and shear strength are the same as those with a flat surface.
In the case of a copper electrode, the same treatment as that for an aluminum electrode may be performed.
[0015]
FIG. 3 (b) shows a solder bump formed by mounting a solder ball as a conductive ball on the UBM created by the above method and reflowing it. As the solder, eutectic solder, various lead-free solders, a core having copper and surrounding solder balls can be used.
[0016]
A method of forming bumps using the UBM according to the present invention and a semiconductor device with bumps formed will be described with reference to FIGS.
In the nickel or nickel-gold plated UBM on which the solder ball is mounted, the joint surface between the solder ball and UBM has a shape as shown by the portion 9 in FIGS. 2 (a) and 3 (a). It is the same size. Here, the particle diameter of the conductive balls to be used as a 2r, when nickel or area of nickel-gold plated pads UBM was S 1, the use of conductive balls satisfy diameter 2r of (Equation 1) Thus, when the metal ball is connected to the UBM, the longitudinal cross-sectional shape of the bonded conductive ball in the semiconductor element is at least larger than a hemispherical shape (eg, (a) and (b) in FIG. 2) (for example, in FIG. (a) and (b)), and bonding with good adhesion can be performed when used as a semiconductor device. If it is smaller than that, it becomes a flat bump shape, making it difficult to use as a chip with good adhesion.
[0017]
When connecting the conductive balls on the UBM, when the displacement of △ r from the average value of the conductive balls having an average diameter 2r m to be used, the individual ball, satisfying conductive (Equation 2) If conductive bumps are formed by using balls, bumps having a uniform height can be obtained, and bonding with good adhesion can be performed when used as a semiconductor device. If it is larger than 0.05, the bump height will vary, and bonding failure will easily occur. Furthermore, if the surface area of each UBM pad is S 1 and S m is the average area of all UBM pads, the height of the conductive bumps can be increased by using UBM that satisfies the condition of (Equation 3). A uniform bump can be obtained, and bonding with good adhesion can be performed when used as a semiconductor element. When the value is larger than 0.1, bonding failure is likely to occur due to variation in bump height after mounting the ball.
[0018]
When bumps are formed, after the conductive balls are mounted on the UBM and joined, the maximum lateral length of the ball in the cross section from the top of the ball to the center of the UBM as shown in FIG. When the height of the ball in the direction is c, the upper part of the ball from the intersection of d and c is a, and the lower part of the intersection is b, 0.5 ≦ c / d <1 and 0 ≦ b A semiconductor device provided with conductive balls so that / a <1 is satisfied. If c / d is smaller than 0.5, the ball after connection becomes smaller than a hemisphere, and it becomes difficult to bond. If c / d is greater than 1, bonding with good adhesion cannot be obtained. When b / a is 0, the ball after the connection is hemispherical, and when b / a is 1 or more, the adhesion is not good.
[0019]
In a semiconductor device in which conductive balls are mounted or bonded on the manufactured UBM, when bonding using bumps, the area of the under bump metal is S, and the height after bonding of the conductive balls is h. When a conductive ball is attached so as to satisfy (Equation 4), a semiconductor device having excellent adhesion can be obtained. This is a state in which the hemisphere is joined at S = πh 2 , and when S> 4πh 2 , the joining property is deteriorated.
In the case of a copper electrode, the same process is performed to obtain a semiconductor device.
[0020]
According to this method, UBM and bumps having a uniform height and shear strength can be formed. If a solder ball is mounted on the UBM and reflowed, it is possible to form a highly reliable solder bump of uniform height with good adhesion, thereby obtaining a semiconductor device. When solder balls are used, solder bumps can be formed at desired positions on the chip or wafer. A uniform value can also be obtained in the shear strength test of the created bump.
[0021]
【Example】
The present invention will be described below with reference to examples. The processing conditions are not limited to these examples.
[0022]
( Reference Example 1)
A chip with a patterned aluminum electrode (thickness: 1 μm) as shown in FIG. 1A (having a 100 μm square aluminum electrode around it, 80 μm square with aluminum coming out of the electrode part, and with a pitch of 140 μm in total There are 200-pin electrodes). As pretreatment, ultrasonic cleaning was performed in acetone for 5 minutes and in ethanol for 5 minutes, respectively. After drying, the substrate was washed with a UV ozone cleaner for 5 minutes. Thereafter, etching is performed at 55 ° C. for 3 minutes using a 50% sulfuric acid aqueous solution. After washing with water, zinc replacement was performed at 25 ° C. for 120 seconds using a commercially available zincate treatment solution: Substar AZ (Okuno Pharmaceutical Co., Ltd.). After water washing, nickel plating was performed at 65 ° C. for 30 minutes using an electroless nickel plating solution: Top Chemialoy 66 (Okuno Pharmaceutical Co., Ltd.). The nickel plating thickness was 5 to 5.5 μm. After washing with water, gold plating was performed at 90 ° C. for 15 minutes using an electroless gold plating solution: Flash Gold NB (Okuno Pharmaceutical). The average area of UBM after plating was 95 2 μm 2 , and the pad area S 1 of each UBM was 92.5 2 to 97.5 2 μm 2 . This is because the surface area S 1 of each UBM pad and the average area S m of all UBM pads satisfy the condition (Equation 3). The gold plating thickness was 0.05 μm. After washing with water, it was dried. The height of UBM was 5 to 5.5 μm.
[0023]
A eutectic solder ball of 100 ± 2 μmφ was used. The average value of the ball diameter used here was 100 μm, and the individual conductive balls used were within 98 to 102 μm. This satisfies the condition of (Equation 2).
Further, the pad area and the particle diameter of the conductive ball satisfy the above (Formula 1).
[0024]
The ball was loaded and reflowed. After reflow, the shear strength of the solder bump was measured. Table 10 shows the 10 measured shear strength values arbitrarily measured. There is little variation in measured values, and it has sufficient strength. The ball height was 77.8 ± 1.5 μm, and the variation was within 2%.
[0025]
In FIG. 6, c / d = 0.65 to 0.66 and b / a = 0.45. Also, when the flip-chip bonding the chip with the electrodes of 80μm square by using this bump, the area S of the UBM is, S = 92.5 2 ~97.5 2 μm 2, after the bonding of the conductive ball The height h was h = 54 μm, which satisfied (Expression 4).
[0026]
( Reference Example 2)
In Reference Example 1, the solder bumps were all subjected to the same conditions except that the zincate treatment for 180 seconds was followed by washing with water, the pickling treatment with 25% nitric acid aqueous solution for 30 seconds, and the second zincate treatment for 120 seconds after washing with water. Created. Thereafter, the shear strength was measured. Table 10 shows 10 measured values arbitrarily measured. There is little variation in measured values. The height of UBM was 5 to 5.5 μm. The ball height was 77.3 ± 1.6 μm.
In FIG. 6, c / d = 0.65 to 0.66 and b / a = 0.45.
[0027]
( Reference Example 3)
In Reference Example 1, the solder bumps are all washed under the same conditions except that the zincate treatment is performed for 120 seconds, followed by washing with water, a 30% aqueous nitric acid solution for 30 seconds, and then the second zincate treatment for 15 seconds. Created. Thereafter, the shear strength was measured. Table 10 shows 10 measured values arbitrarily measured. There is little variation in measured values. The height of UBM was 5 to 5.5 μm. The ball height was 77.3 ± 1.6 μm.
In FIG. 6, c / d = 0.65 to 0.66 and b / a = 0.45.
[0028]
Example 4
In Reference Example 1, the zincate treatment for 120 seconds was followed by washing with water, followed by pickling treatment with a 25% nitric acid solution for 15 seconds, followed by washing with water and then the second zincate treatment for 120 seconds. Solder bumps were produced under the same conditions except that USD (Okuno Pharmaceutical Co., Ltd .: plating at 85 ° C. for 30 minutes) was used. A UBM with a recessed center was obtained. Thereafter, the shear strength was measured. Table 10 shows 10 measured values arbitrarily measured. There is little variation in measured values. The height of UBM was 5 to 5.5 μm. The ball height was 77.2 ± 1.7 μm.
In FIG. 6, c / d = 0.65 to 0.66 and b / a = 0.45.
[0031]
(Comparative example)
Except that the organic solvent cleaning and UV ozone cleaning were not performed in the pretreatment, the same processing as in Reference Example 1 was performed to form solder bumps. The shear strength was measured. Table 10 shows arbitrarily measured values (measured values of shear strength (unit: gf / pin)). There are large variations in measured values. The height of UMB was 4.5 to 5.5 μm, and the variation was somewhat large. The ball height is 77.3 ± 2.7μm, and the variation is large.
[0032]
[Table 1]
Figure 0004703835
[0033]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained. According to this method, a UBM or bump having a uniform height can be formed on an aluminum or copper electrode. If solder balls are mounted on the UBM and reflowed, solder bumps of uniform height can be formed. In addition, a reliable semiconductor device having a uniform height bump is obtained in this way.
[Brief description of the drawings]
FIG. 1 is a diagram showing UBM creation of nickel gold by electroless plating, (a) after aluminum electrode patterning, (b) zincate treatment (zinc substitution) or palladium treatment, (c) electroless nickel plating , (D) shows electroless gold plating.
FIG. 2 is a diagram showing a difference in solder ball shape after reflow, (a) is a view of UBM from the top (small ball), and (b) is a cross-sectional view of UBM from the side (small ball). is there.
FIG. 3 is a diagram showing the difference in solder ball shape after reflow, (a) is a view of UBM from the top (large ball), (b) is a cross-sectional view of UBM from the side (large ball). is there.
[Fig. 4] Peripheral raised electrode [Fig. 5] Periphery raised electrode (cross-sectional view)
[Figure 6] Cross-sectional view of solder balls reflowed on UBM [Explanation of symbols]
1. 1. Silicon substrate with SiO 2 oxide film 2. Aluminum electrode Silicon nitride film or silicon oxide film (passivation film)
4). Zn film5. 5. Ni-B or Ni-P film or a mixed film thereof Au film 7. 7. Solder balls 8. Outer frame of passivation film on electrode UBM part

Claims (6)

半導体素子の電極上に金属メッキにより形成したアンダーバンプメタルであって、中央部分が凹み外周部分がせり上がった形状であり、外周部分が中央部分より厚い部分を有することを特徴とするアンダーバンプメタル。A under-bump metal formed by metal plating on the electrode of the semiconductor element, Ri shape der the central portion outer peripheral portion recessed rose auction, characterized Rukoto outer peripheral portion having a thicker portion than the central portion Under bump metal. 請求項1記載のアンダーバンプメタル上に、導電性ボールを搭載後、接着またはリフローして形成したものであることを特徴とする半導体装置用バンプ。  A bump for a semiconductor device, which is formed by bonding or reflowing a conductive ball on the under bump metal according to claim 1 after mounting the conductive ball. 前記導電性ボールが、該導電性ボールの粒径を 2rとし、各アンダーバンプメタルのメッキパッドの面積をS1とした時、
(S1/π)3/2 < 2(r3 ) (式1)
を満たす粒径2rの導電性ボールであることを特徴とする請求項2記載の半導体装置用バンプ。
When the conductive balls, the particle diameter of the conductive balls and 2r, the area of the plating pads of each under-bump metal was S 1,
(S 1 / π) 3/2 < 2 (r 3) ( Equation 1)
The bump for a semiconductor device according to claim 2, wherein the bump is a conductive ball having a particle diameter of 2r satisfying the above condition.
前記導電性ボールが、該導電性ボールの粒径と使用する導電性ボールの平均粒径2rm との差を△rとした時、個々のボールが
| △r|/2rm < 0.05 (式2)
である条件を満たす導電性ボールであって、
前記アンダーバンプメタルが、各アンダーバンプメタルパッドの表面積をS1とし、 Smを全アンダーバンプメタルパッドの平均の面積とした時、
0 < |{S1− Sm}|/Sm < 0.1 (式3)
である条件を満たすアンダーバンプメタルであることを特徴とする請求項2又は3に記載の半導体装置用バンプ。
The conductive balls, when the difference between the average particle diameter 2r m of the conductive balls to be used as the particle diameter of the conductive balls △ was r, individual balls
Δr | / 2r m <0.05 (Formula 2)
A conductive ball that satisfies the following condition:
When the surface area of each under bump metal pad is S 1 and S m is the average area of all under bump metal pads,
0 <| {S 1 - S m} | / S m <0.1 ( Equation 3)
The bump for a semiconductor device according to claim 2, wherein the bump is an under bump metal that satisfies the following condition.
請求項2乃至4のいずれかに記載の半導体装置用バンプを有する半導体装置であって、アンダーバンプメタル上に搭載し接合した導電性ボールの頂上からアンダーバンプメタルの中心部への断面におけるボールの横方向の最大長さをd、縦方向のボールの高さをcとし、ボール断面でdとcの交点から上の部分をaとし、交点の下の部分をbとした時、0.5 ≦ c/d <1かつ、0 ≦b/a < 1 となることを特徴とする導電性ボール付半導体装置。  5. A semiconductor device having a bump for a semiconductor device according to claim 2, wherein the ball in a cross section from the top of the conductive ball mounted on and bonded to the under bump metal to the center of the under bump metal. When the maximum horizontal length is d, the height of the vertical ball is c, the upper part of the ball cross section from the intersection of d and c is a, and the lower part of the intersection is b. <= C / d <1 and 0 <= b / a <1 It is a semiconductor device with a conductive ball characterized by the above-mentioned. 請求項2乃至4のいずれかに記載の半導体装置用バンプを有する半導体装置におけるアンダーバンプメタル上に接合された導電性ボールに、更に他の電極が接合され、前記のアンダーバンプメタルの面積をSとし、導電性ボールの接合後の高さをhとした時、
S < 4πh2 (式4)
となることを特徴とする導電性ボール付半導体装置。
5. Another electrode is bonded to the conductive ball bonded on the under bump metal in the semiconductor device having the bump for a semiconductor device according to claim 2, and the area of the under bump metal is reduced to S. And when the height after bonding of the conductive balls is h,
S <4πh 2 (Formula 4)
A semiconductor device with a conductive ball.
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JP2000200798A (en) * 1999-01-06 2000-07-18 Hitachi Ltd Semiconductor device and its mounting board
JP2000260801A (en) * 1999-03-11 2000-09-22 Toshiba Corp Semiconductor device and method of producing the same
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