JP2004250577A - Film-shaped adhesive, leadframe and semiconductor device equipped with film-shaped adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film-shaped adhesive that maintains its heat resistance, even if its glass transition temperature is lowered, exhibit a good flowability at the time of bonding and has a good storability. <P>SOLUTION: The film-shaped adhesive which is supported on a substrate and is used for bonding a semiconductor element to a leadframe in the fabrication process of a semiconductor device is manufactured by casting on the substrate a polyimide resin which is a polyimide obtained by reacting at least one diamine compound selected from a diaminopolysiloxane, an aromatic diamine and an aliphatic diamine with an aromatic tetracarboxylic acid anhydride and contains &ge; 1 mol.% of the structure as expressed by formula (2) among the total -NH-R-NH- (wherein R is a residue after two NH<SB>2</SB>'s are removed from the diamine compound). <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

（式中、Ｒ_１、Ｒ_２は炭素数１〜４の二価の脂肪族基又は芳香族基、Ｒ_３、Ｒ_４、Ｒ_５及びＲ_６は一価の脂肪族基又は芳香族基を表し、ｋは１〜１００の整数である。）
【化４】

［２］ ［１］項記載の基材に担持されたフィルム状接着剤をリードフレームに接着してなることを特徴とするフィルム状接着剤付リードフレーム、
［３］ ［２］項記載のフィルム状接着剤付リードフレームを用いてなることを特徴とする半導体装置
である。
【０００９】
【発明の実施の形態】
本発明に用いられる式（２）で示される構造は、分子内にかさ高い側鎖構造（カルド構造）を有しており、この構造を含むジアミンを用いて得られるポリイミド樹脂の主鎖には、この側鎖が導入されるために分子鎖間引力が低下し、高温での線膨張係数が大きくなり、更に耐熱性を低下させることなく、線膨張係数が大きいことに起因してフィルム状接着剤の接着時のフロー性を向上させることができる。又ポリイミド樹脂の溶剤として、通常用いられているＮ−メチル−２−ピロリドン等への溶解性にも優れている。 本発明に用いられるポリイミド樹脂中の全−ＨＮ―Ｒ―ＮＨ−（Ｒはジアミン化合物から２つのＮＨ_２を除いた残基）のうち、式（２）で示される構造を１モル％以上、更に好ましくは５モル％以上含むことにより、ガラス転移温度が低くなっても耐熱性を低下させることなくフィルム状接着剤の接着時のフロー性を向上させることができる。
【００１０】
一般式（１）で表されるジアミノシロキサン化合物はポリイミド樹脂のガラス転移温度を下げて接着性を向上させる為に用いるが、ポリイミド樹脂を接着層した接着テープの接着性の観点から、その構成比がアミン成分中のモル比で０．３から０．５の範囲にあることが望ましい。０．３を下回るとガラス転移温度が上昇し、２５０〜３００℃での被着体への濡れ性が不足し接着することが困難になる。また０．５を上回ると接着はできるが同時にフィルム自体の熱変形が大きくて気泡が無く均一に接着することが困難になる。
【００１１】
本発明に用いる芳香族ジアミンもしくは脂肪族ジアミンとしては、３，３’−ジメチル−４，４’−ジアミノビフェニル、４，６−ジメチル−ｍ−フェニレンジアミン、２，５−ジメチル−ｐ−フェニレンジアミン、２，４−ジアミノメシチレン、４，４’−メチレンジ−ｏ−トルイジン、４，４’−メチレンジアミン−２，６−キシリジン、４，４‘−メチレン−２，６−ジエチルアニリン、２，４−トルエンジアミン、ｍ−フェニレンジアミン、ｐ−フェニレンジアミン、４，４’−ジアミノジフェニルプロパン、３，３’−ジアミノジフェニルプロパン、４，４’−ジアミノジフェニルエタン、３，３’−ジアミノジフェニルエタン、４，４’−ジアミノジフェニルメタン、３，３’−ジアミノジフェニルメタン、４，４’−ジアミノジフェニルスルフィド、３，３’−ジアミノジフェニルスルフィド、４，４’−ジアミノジフェニルスルフォン、３，３’−ジアミノジフェニルスルフォン、４，４’−ジアミノジフェニルエ−テル、３，３’−ジアミノジフェニルエ−テル、ベンジジン、３，３’−ジアミノビフェニル、３，３’−ジメチル−４，４’−ジアミノビフェニル、３，３’−ジメトキシベンジジン、ビス（ｐ−アミノシクロヘキシル）メタン、ビス（ｐ−β−アミノ−ｔ−ブチルフェニル）エ−テル、ビス（ｐ−β−メチル−δ−アミノペンチル）ベンゼン、ｐ−ビス（２−メチル−４−アミノペンチル）ベンゼン、１，５−ジアミノナフタレン、２，６−ジアミノナフタレン、２，４−ビス（β−アミノ−ｔ−ブチル）トルエン、２，４−ジアミノトルエン、ｍ−キシレン−２，５−ジアミン、ｐ−キシレン−２，５−ジアミン、ｍ−キシリレンジアミン、ｐ−キシリレンジアミン、２，６−ジアミノピリジン、２，５−ジアミノピリジン、２，５−ジアミノ−１，３，４−オキサジアゾ−ル、１，４−ジアミノシクロヘキサン、ピペラジン、メチレンジアミン、エチレンジアミン、テトラメチレンジアミン、ペンタメチレンジアミン、ヘキサメチレンジアミン、２，５−ジメチルヘキサメチレンジアミン、３−メトキシヘキサメチレンジアミン、ヘプタメチレンジアミン、２，５−ジメチルヘプタメチレンジアミン、３−メチルヘプタメチレンジアミン、４，４−ジメチルヘプタメチレンジアミン、オクタメチレンジアミン、ノナメチレンジアミン、５−メチルノナメチレンジアミン、デカメチレンジアミン、１，３−ビス（３−アミノフェノキシ）ベンゼン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン、１，３−ビス（４−アミノフェノキシ）ベンゼン、ビス−４−（４−アミノフェノキシ）フェニルスルフォン、ビス−４−（３−アミノフェノキシ）フェニルスルフォン，３（４），８（９）−ビス（アミノメチル）−トリシクロ−５，２，１，０（２．６）デカン，ＮＢＤＡ：２，５（２，６）−ビス（アミノメチル）ビシクロ［２．２．１］ヘプタン，３，９−ビス（３−アミノプロピル）−２，４，８，１０テトラオキサスピロ［５．５］ウンデカン等を挙げることができる。これらのジアミンは、単独でも併用してもよい。
【００１２】
本発明に用いる芳香族テトラカルボン酸二無水物としては、３，３’，４，４’−ビフェニルテトラカルボン酸二無水物、３，３’，４，４’−ベンゾフェノンテトラカルボン酸二無水物、ピロメリット酸二無水物、４，４’−オキシジフタル酸二無水物、エチレングリコールビストリメリット酸二無水物、が挙げられる。中でも、４，４’−オキシジフタル酸二無水物が好ましい。これらの芳香族テトラカルボン酸二無水物は、単独でも併用してもよい。
【００１３】
本発明に用いられるポリイミド樹脂の重縮合反応における芳香族テトラカルボン酸二無水物とジアミン化合物の当量比［（全芳香族テトラカルボン酸二無水物の当量数）／（全ジアミン化合物の当量数）］は、得られるポリイミド樹脂の分子量を決定する重要な因子である。ポリイミド樹脂分子量と物性、特に数平均分子量と機械的特性の間には相関があることは良く知られている。数平均分子量が大きいほど機械的特性が優れている。従って、実用的に優れた機械的強度を得るためには、ある程度高分子量であることが必要である。
【００１４】
当量比としては、０．９００〜１．０６が好ましく、更に好ましくは０．９７５〜１．０２５が望ましい。この範囲内ならば機械的強度及び耐熱性が両立する。当量比が下限値未満では、分子量が小さくフィルム状接着剤は脆くなり、上限値を越えると未反応のカルボン酸が加熱時に脱炭酸して、ガス発生や発泡の原因となり好ましくない。ポリイミド樹脂の分子量制御のために、芳香族テトラカルボン酸二無水物以外のジカルボン酸二無水物或いはモノアミンを反応に用いることは、前記の当量比の範囲内であれば、特に問題ない。
【００１５】
本発明でのポリイミド樹脂の製造時に用いる溶剤は、ポリイミド樹脂を溶解するものならば、特に限定しないがポリイミド樹脂に対して良溶剤であるＮ−メチル−２−ピロリドン、ジメチルアセトアミド等が好ましい。 更に反応時に、共沸用溶剤として前記溶剤と相溶性のあるトルエン、キシレン、ソルベントナフサ等の芳香族炭化水素を用いてもよい。これはイミド化反応に伴って生成する水を系外に、できるだけ速く排出するためである。用いる量としては、前記溶剤と相溶性のあるトルエン、キシレン、ソルベントナフサ等の芳香族炭化水素が、全溶剤中５０重量％以下が好ましい。５０重量％を越えると溶剤の溶解力が低下し、原料のジアミノポリシロキサン、芳香族ジアミンもしくは脂肪族ジアミン又はポリイミド樹脂が析出するおそれがあり好ましくない。
【００１６】
本発明に用いられるポリイミド樹脂の合成は反応容器に、例えばＮ−メチル−２−ピロリドン、ジメチルアセトアミド等の溶剤を仕込み、式（１）で示されるジアミンと、一般式（２）で示されるジアミノポリシロキサン、芳香族ジアミンもしくは脂肪族ジアミンの中から選ばれる少なくとも１つのジアミン化合物を投入して均一に溶解し、３０℃以下に保ちながら芳香族テトラカルボン酸二無水物を投入して、３０℃を越えない温度下で攪拌混合してポリアミド酸を得た後、必要によって共沸溶剤としてトルエン等の芳香族炭化水素を添加して反応系が還流状態になるまで加熱昇温をし、還流反応状態を維持してイミド化を進め、イミド化により生成した水を系外に排出してポリイミド樹脂溶液を得る。
【００１７】
得られたポリイミド樹脂溶液は、例えばロールや金属シート又はポリエステルシート等の基材である離型シート上にフローコーター、ロールコーター等を用いて、流延又は塗布し、ポリイミド樹脂層からなるフィルムを形成させ、好ましくは５０〜２６０℃、更に好ましくは８０〜２３０℃で０．１〜１時間程度加熱乾燥することにより完全に溶剤が除去され、フィルム状接着剤を接着する際、残存溶剤による発泡を抑制できる、基材に担持された均一なフィルム状接着剤を製造することができる。
【００１８】
また本発明のフィルム接着剤を半導体装置の組立に用いたとき、低吸水性・高温時の接着性に優れていることから高信頼性の半導体装置を提供することが可能となる。
【００１９】
【実施例】
以下、実施例により本発明を更に詳細に説明するが、本発明は、何らこれらに限定されるものではない。
なお、実施例における略号は以下の通りである。
ＰＩ：ポリイミド樹脂溶液
ＯＤＰＡ：４，４’−オキシジフタル酸二無水物
ＢＡＰＰ：２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン
ＡＰＢ： １，３−ビス（３−アミノフェノキシ）ベンゼン
ＡＰＰＳ−１：α，ω−ビス（３−アミノプロピル）ポリジメチルシロキサン（平均分子量２４９）（式（１）においてｋ＝１）
ＡＰＰＳ−９：α，ω−ビス（３−アミノプロピル）ポリジメチルシロキサン（平均分子量８３７）（式（１）においてｋ＝９）
ＢＡＦＬ：９，９−ビス（４−アミノフェニル）フルオレン（式（３））
ＮＭＰ：Ｎ−メチル−２−ピロリドン
【００２０】
【化５】

【００２１】
（ＰＩ−１の合成）
乾燥窒素ガス導入管、冷却器、温度計、攪拌機を備えた四口フラスコにＮＭＰ６６７．７４ｇを入れ窒素ガスを流した。次にアミン成分であるＡＰＢ １０８．１６ｇ（０．３７モル）とＡＰＰＳ−９ １８．２２ｇ（０．０２２モル）、ＡＰＰＳ−１ ５．４１ｇ（０．０２２モル）、ＢＡＦＬ ７．５８ｇ（０．０２２モル）を投入し、均一になるまで撹拌した。均一に溶解後、系を２０℃に保ちながら、酸成分であるＯＤＰＡ １３５．０４ｇ（０．４３５モル）を１０分間かけて添加し、その後２時間撹拌を続けポリアミド酸溶液を得た。この間フラスコは２０℃を保った。その後窒素ガス導入管と冷却器を外し、トルエンを満たしたディーン・スターク管をフラスコに装着し、系にトルエン ７４．１９３ｇを添加した。油浴で系を還流温度まで加熱昇温して還流状態を維持しながら発生する水を系外に排出した。３時間加熱した後冷却し、ポリイミド樹脂溶液ＰＩ−１を得た。
【００２２】
（ＰＩ−２の合成）
乾燥窒素ガス導入管、冷却器、温度計、攪拌機を備えた四口フラスコにＮＭＰ６６１．４８ｇを入れ、窒素ガスを流した。次にアミン成分であるＡＰＢ ４３．８５ｇ（０．１５モル）とＡＰＰＳ−９ ６２．８ｇ（０．０７５モル）、ＡＰＰＳ−１ １８．６ｇ（０．０７５モル）、ＢＡＦＬ ２６．１３ｇ（０．０７５モル）を投入し、均一になるまで撹拌した。均一に溶解後、系を２０℃に保ちながら、酸成分であるＯＤＰＡ １１６．３３ｇ（０．３７５モル）を１０分間かけて添加し、その後２時間撹拌を続けポリアミド酸溶液を得た。この間フラスコは２０℃を保った。その後窒素ガス導入管と冷却器を外し、トルエンを満たしたディーン・スターク管をフラスコに装着し、系にトルエン ７２．３９ｇを添加した。油浴で系を還流温度まで加熱昇温して還流状態を維持しながら発生する水を系外に排出した。３時間加熱した後冷却し、ポリイミド樹脂溶液ＰＩ−２を得た。
【００２３】
（ＰＩ−３の合成）
乾燥窒素ガス導入管、冷却器、温度計、攪拌機を備えた四口フラスコにＮＭＰ９５０ｇを入れ、窒素ガスを流した。次にアミン成分であるＡＰＢ １０．２３（０．０３５モル）とＢＡＰＰ ５０．２９ｇ（０．１２３モル）、ＡＰＰＳ−９ ５８．５９ｇ（０．０７モル）、ＡＰＰＳ−１ １７．４ｇ（０．０７モル）、ＢＡＦＬ １８．２９ｇ（０．０５３モル）を投入し、均一になるまで撹拌した。均一に溶解後、系を２０℃に保ちながら、酸成分であるＯＤＰＡ １０８．５８ｇ（０．０３５モル）を１０分間かけて添加し、その後２時間撹拌を続けポリアミド酸溶液を得た。この間フラスコは２０℃を保った。その後窒素ガス導入管と冷却器を外し、トルエンを満たしたディーン・スターク管をフラスコに装着し、系にトルエン ７１．２ｇを添加した。油浴で系を還流温度まで加熱昇温して還流状態を維持しながら発生する水を系外に排出した。３時間加熱した後冷却し、ポリイミド樹脂溶液ＰＩ−３を得た。
【００２４】
（ＰＩ−４の合成）
乾燥窒素ガス導入管、冷却器、温度計、攪拌機を備えた四口フラスコにＮＭＰ６７８．７４ｇを入れ、窒素ガスを流した。次にアミン成分であるＡＰＢ１１６．９３ｇ（０．４０モル）とＡＰＰＳ−９ １８．６０ｇ（０．０２２モル）、ＡＰＰＳ−１ ５．４１ｇ（０．０２２モル）を投入し、均一になるまで撹拌した。均一に溶解後、系を２０℃に保ちながら、酸成分であるＯＤＰＡ １３７．８７ｇ（０．４４４モル）を１０分間かけて添加し、その後２時間撹拌を続けポリアミド酸溶液を得た。この間フラスコは２０℃を保った。その後窒素ガス導入管と冷却器を外し、トルエンを満たしたディーン・スターク管をフラスコに装着し、系にトルエン ７５．４２ｇを添加した。油浴で系を還流温度まで加熱昇温して還流状態を維持しながら発生する水を系外に排出した。３時間加熱した後冷却し、ポリイミド樹脂溶液ＰＩ−４を得た。
【００２５】
（ＰＩ−５の合成）
乾燥窒素ガス導入管、冷却器、温度計、攪拌機を備えた四口フラスコにＮＭＰ６９４．５５ｇを入れ、窒素ガスを流した。次にアミン成分であるＢＡＰＰ １４３．６８ｇ（０．３５０モル）とＡＰＰＳ−９ １６．２８ｇ（０．０１９モル）、ＡＰＰＳ−１ ４．８３ｇ（０．０１９モル）を投入し、均一になるまで撹拌した。均一に溶解後、系を２０℃に保ちながら、酸成分であるＯＤＰＡ １２０．６４ｇ（０．３８９モル）を１０分間かけて添加し、その後２時間撹拌を続けポリアミド酸溶液を得た。この間フラスコは２０℃を保った。その後窒素ガス導入管と冷却器を外し、トルエンを満たしたディーン・スターク管をフラスコに装着し、系にトルエン ７７．１７ｇを添加した。油浴で系を還流温度まで加熱昇温して還流状態を維持しながら発生する水を系外に排出した。３時間加熱した後冷却し、ポリイミド樹脂溶液ＰＩ−５を得た。
【００２６】
表１に、上記で得たポリイミド樹脂溶液ＰＩ−１〜５の配合量割合を示す。表１の配合数値はモル比を示す。ポリイミド樹脂溶液ＰＩ−１〜５をシリコン離型処理二軸延伸ポリエステルフィルムにロールコーターで、厚みが２５μｍになるように塗布し、８０℃で２分、１３０℃で２分、１８０℃で２分乾燥を行い、ポリエステルフィルムに担持された厚さ２５μｍのフィルム状接着剤を得た。このフィルム状接着剤のガラス転移温度及び線熱膨張係数を測定した。結果を表１に示す。
【００２７】
ガラス転移温度・線熱膨張係数：フィルム状接着剤を厚み２５μｍ幅３ｍｍの矩形に切り出し，熱機械分析装置（ＴＭＡ，セイコーインスツルメンツ（株）製，ＳＳ−６０００）を用いて昇温速度５℃／分，荷重２５ｍＮの条件で測定した。解析ソフトによりＴＭＡ曲線の外挿点よりガラス転移温度（℃）、所定温度範囲［（３０〜７０℃）、（１６０〜１７０℃）］での線熱膨張係数を算出した。結果を表１に示す。
【００２８】
次に、得られたポリイミド樹脂溶液を市販ポリイミドフィルム（ユーピレックス５０ＳＧＡ、宇部興産（株））の両面に塗布して８０〜２３０℃の温度で乾燥し、ポリイミドフィルムに担持されたフィルム状接着剤を得た。このフィルム状接着剤の接着強度、熱分解温度を測定した。結果を表１に示す。
【００２９】
接着強度：ポリイミドフィルムの両面に担持されたフィルム状接着剤を４２アロイのプレートに３００℃にて熱圧着し試験片を作成した後圧力を開放後、３００℃で３０秒間アニ−ルした。接着面にかかる圧力はゲージ圧力と接着面積から計算の結果４ｋｇｆ／ｃｍ^２であった。この試験片について１８０℃でのピール強度（Ｎｍ）を測定した。結果を表１に示す。
【００３０】
熱分解温度：前記ポリイミドフィルムに担持されたフィルム状接着剤から得たフィルム状接着剤を１０ｍｇ前後精秤し、熱重量分析装置（ＴＧＤＴＡ，セイコーインスツルメンツ（株）社製，ＳＳ−６０００）を用いて昇温速度１０℃／分の条件で測定した。解析ソフトにより重量減少５％での温度を熱分解温度（℃）として算出した。結果を表１に示す。
【００３１】
【表１】

【００３２】
【発明の効果】
本発明に従えば、ガラス転移温度を低くしても耐熱性が低下せず、接着時のフロー性に優れ、更に保存性にも優れた特性を有するフィルム状接着剤が得られ、ガラス転移温度の低下により、従来より半導体素子とリードフレームとの接着時の温度を低く設定できるため半導体装置組立工程での部材への熱衝撃を抑えることが可能となり、高信頼性の半導体装置を得ることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film adhesive excellent in heat resistance and low temperature processability, a lead frame with a film adhesive, and a semiconductor device using the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the progress of high performance, large capacity, and light weight of semiconductor elements, various properties are required for a film adhesive used for bonding a semiconductor element to a lead frame. For example, one of the most important characteristics is the temperature at which a semiconductor element and a lead frame are bonded via a film adhesive. This is to increase the circuit pattern density in order to increase the capacity and space of the semiconductor device, and to reduce the thermal damage to the fine circuit and the warpage of the semiconductor device when heat is applied, due to the thinner semiconductor device. This is because it is necessary to minimize the heat applied when bonding the film adhesive. For this reason, a film-like adhesive that can be bonded at about 300 ° C. or lower has been demanded, although it is conventionally bonded at about 400 ° C.
[0003]
In order to solve this problem, it is conceivable to lower the glass transition temperature of the film adhesive and bond the film adhesive at a lower temperature. However, simply lowering the glass transition temperature lowers the heat resistance of the film adhesive and the adhesive strength under high temperature and high humidity, and the heat generated during the bonding of the film adhesive causes the film adhesive itself to foam. Or the assembling work such as wire bonding in a high-temperature atmosphere may be difficult, or the reliability of the semiconductor device may be impaired.
[0004]
On the other hand, a film adhesive in which a thermosetting component such as an epoxy resin and a curing agent thereof is mixed with a heat-resistant polyimide resin in which the adhesive strength does not decrease even when the glass transition temperature is lowered has been put to practical use (for example, And Patent Document 1). It can be bonded at a lower temperature than the conventional bonding temperature by blending a thermosetting component containing an epoxy resin with excellent adhesive strength and a low glass transition temperature into a heat-resistant polyimide resin. There is no problem in assembling work such as wire bonding under a high temperature atmosphere, and furthermore, it is excellent in reliability, for example, it does not peel off in a temperature range of a sealing process by a sealing material or a soldering process at the time of mounting. A semiconductor device can be obtained.
[0005]
However, such a thermoplastic resin / thermosetting resin hybrid type adhesive requires a step of heat curing as compared with the thermoplastic resin, has poor storage stability of the film adhesive, and has a thermosetting property. There are drawbacks such as that there are many impurities derived from the sex component. Further, since the polyimide resin is used as the base resin, the flow property at the time of bonding the film adhesive is inferior. If the flow property is poor, the unevenness between the lead frame and the semiconductor element attachment surface cannot be buried without a gap, which is a negative factor. For this reason, there is a demand for a film adhesive which is excellent in heat resistance, does not lower the adhesive strength even when the glass transition temperature is lowered, has excellent flowability at the time of bonding, and further has excellent storage stability.
[0006]
[Patent Document 1]
JP-A-7-224150 (all pages)
[0007]
[Problems to be solved by the invention]
The present invention is a high performance and large capacity of a semiconductor element, with the weight reduction, as a result of intensive studies in view of the problem of the semiconductor device assembly process, by using a polyimide resin obtained by using a specific diamine, Even if the glass transition temperature is lowered, the heat resistance does not decrease, the flow property at the time of bonding is excellent, and the film adhesive having characteristics excellent in storage stability, a lead frame with a film adhesive, and the same were used. A semiconductor device is provided.
[0008]
That is, the present invention:
[1] At least one diamine compound selected from diaminopolysiloxane, aromatic diamine or aliphatic diamine represented by the general formula (1), wherein the adhesive for bonding the semiconductor element and the lead frame in the assembly process of the semiconductor device is And a polyimide obtained by reacting an aromatic tetracarboxylic acid anhydride with all-HN—R—NH— (R is a residue obtained by removing two NH ₂ from a diamine compound). A film-like adhesive carried on a substrate, characterized by being cast on a substrate a polyimide resin containing 1 mol% or more of the structure represented by
Embedded image

(Wherein, R ₁ and R _{2 each} represent a divalent aliphatic group or an aromatic group having 1 to 4 carbon atoms, and R ₃ , R ₄ , R ₅ and R ₆ represent a monovalent aliphatic group or an aromatic group. And k is an integer of 1 to 100.)
Embedded image

[2] A lead frame with a film adhesive, wherein the film adhesive carried on the substrate according to [1] is adhered to a lead frame.
[3] A semiconductor device using the lead frame with a film adhesive according to [2].
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The structure represented by the formula (2) used in the present invention has a bulky side chain structure (cardo structure) in the molecule, and the main chain of the polyimide resin obtained by using a diamine containing this structure is Since the side chains are introduced, the attractive force between the molecular chains is reduced, the coefficient of linear expansion at high temperatures is increased, and the film-like adhesion is caused by the large coefficient of linear expansion without further lowering the heat resistance. The flow property at the time of bonding the agent can be improved. Also, it has excellent solubility in N-methyl-2-pyrrolidone or the like which is generally used as a solvent for the polyimide resin. Of all -HN-R-NH- polyimide resin used in the present invention (residues R are obtained by removing two NH ₂ diamine compound), the structure represented by formula (2) 1 mol% or more, More preferably, by containing 5 mol% or more, even when the glass transition temperature is lowered, the flow property at the time of bonding the film adhesive can be improved without lowering the heat resistance.
[0010]
The diaminosiloxane compound represented by the general formula (1) is used to lower the glass transition temperature of the polyimide resin to improve the adhesiveness. Is preferably in the range of 0.3 to 0.5 in terms of molar ratio in the amine component. If it is less than 0.3, the glass transition temperature rises, and the wettability to the adherend at 250 to 300 ° C. becomes insufficient, making it difficult to adhere. On the other hand, if it exceeds 0.5, adhesion can be achieved, but at the same time, the thermal deformation of the film itself is large, and it is difficult to adhere uniformly without bubbles.
[0011]
As the aromatic diamine or aliphatic diamine used in the present invention, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine , 2,4-diaminomesitylene, 4,4'-methylenedi-o-toluidine, 4,4'-methylenediamine-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 2,4 -Toluenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfur 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether , Benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, bis (p-aminocyclohexyl) methane, bis (p-β-amino -T-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6 -Diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine , P-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazo -1,4-diaminocyclohexane, piperazine, methylenediamine, ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, 3-methoxyhexamethylenediamine, heptamethylenediamine, 5,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, octamethylenediamine, nonamethylenediamine, 5-methylnonamethylenediamine, decamethylenediamine, 1,3-bis (3 − Minophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis (4-aminophenoxy) benzene, bis-4- (4-aminophenoxy) phenylsulfone, bis -4- (3-Aminophenoxy) phenylsulfone, 3 (4), 8 (9) -bis (aminomethyl) -tricyclo-5,2,1,0 (2.6) decane, NBDA: 2,5 ( 2,6) -bis (aminomethyl) bicyclo [2.2.1] heptane, 3,9-bis (3-aminopropyl) -2,4,8,10 tetraoxaspiro [5.5] undecane and the like Can be mentioned. These diamines may be used alone or in combination.
[0012]
The aromatic tetracarboxylic dianhydride used in the present invention includes 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 3,3', 4,4'-benzophenonetetracarboxylic dianhydride , Pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, and ethylene glycol bistrimellitic dianhydride. Among them, 4,4′-oxydiphthalic dianhydride is preferred. These aromatic tetracarboxylic dianhydrides may be used alone or in combination.
[0013]
Equivalent ratio of aromatic tetracarboxylic dianhydride to diamine compound in the polycondensation reaction of the polyimide resin used in the present invention [(equivalent number of all aromatic tetracarboxylic dianhydrides) / (equivalent number of all diamine compounds) Is an important factor that determines the molecular weight of the obtained polyimide resin. It is well known that there is a correlation between the molecular weight of a polyimide resin and physical properties, in particular, the number average molecular weight and mechanical properties. The larger the number average molecular weight, the better the mechanical properties. Therefore, in order to obtain practically excellent mechanical strength, it is necessary to have a high molecular weight to some extent.
[0014]
The equivalent ratio is preferably from 0.900 to 1.06, more preferably from 0.975 to 1.025. Within this range, both mechanical strength and heat resistance are compatible. If the equivalent ratio is less than the lower limit, the molecular weight is small and the film adhesive becomes brittle. If the equivalent ratio exceeds the upper limit, unreacted carboxylic acid is decarboxylated during heating, causing gas generation and foaming. The use of dicarboxylic dianhydride or monoamine other than aromatic tetracarboxylic dianhydride in the reaction for controlling the molecular weight of the polyimide resin is not particularly problematic as long as it is within the above-mentioned equivalent ratio.
[0015]
The solvent used in the production of the polyimide resin in the present invention is not particularly limited as long as it can dissolve the polyimide resin, but N-methyl-2-pyrrolidone, dimethylacetamide and the like, which are good solvents for the polyimide resin, are preferable. Further, at the time of the reaction, an aromatic hydrocarbon such as toluene, xylene, or solvent naphtha which is compatible with the solvent may be used as the azeotropic solvent. This is to discharge water generated during the imidization reaction out of the system as quickly as possible. The amount of the aromatic hydrocarbon, such as toluene, xylene, or solvent naphtha, which is compatible with the solvent, is preferably 50% by weight or less in the total solvent. If it exceeds 50% by weight, the solvent's dissolving power is reduced, and the raw material diaminopolysiloxane, aromatic diamine, aliphatic diamine or polyimide resin may be undesirably precipitated.
[0016]
In the synthesis of the polyimide resin used in the present invention, a solvent such as N-methyl-2-pyrrolidone or dimethylacetamide is charged into a reaction vessel, and a diamine represented by the formula (1) and a diamino represented by the general formula (2) are added. At least one diamine compound selected from a polysiloxane, an aromatic diamine or an aliphatic diamine is charged and uniformly dissolved, and an aromatic tetracarboxylic dianhydride is charged while maintaining the temperature at 30 ° C. or lower, and the temperature is reduced to 30 ° C. After stirring and mixing at a temperature not exceeding 350 ° C. to obtain a polyamic acid, if necessary, an aromatic hydrocarbon such as toluene is added as an azeotropic solvent, and the temperature is increased by heating until the reaction system is brought into a reflux state. The imidation is advanced while maintaining the state, and water generated by the imidation is discharged out of the system to obtain a polyimide resin solution.
[0017]
The obtained polyimide resin solution is cast or applied using a flow coater, a roll coater, or the like on a release sheet that is a base material such as a roll or a metal sheet or a polyester sheet, to form a film including a polyimide resin layer. The solvent is completely removed by heating and drying at about 50 to 260 ° C., more preferably at about 80 to 230 ° C. for about 0.1 to 1 hour. It is possible to produce a uniform film-like adhesive supported on a substrate, which can suppress the occurrence of the adhesive.
[0018]
Further, when the film adhesive of the present invention is used for assembling a semiconductor device, it is possible to provide a highly reliable semiconductor device because of its low water absorption and excellent adhesiveness at high temperatures.
[0019]
【Example】
Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
Abbreviations in the examples are as follows.
PI: Polyimide resin solution ODPA: 4,4'-oxydiphthalic dianhydride BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane APB: 1,3-bis (3-aminophenoxy) benzene APPS-1: α, ω-bis (3-aminopropyl) polydimethylsiloxane (average molecular weight: 249) (k = 1 in formula (1))
APPS-9: α, ω-bis (3-aminopropyl) polydimethylsiloxane (average molecular weight 837) (k = 9 in the formula (1))
BAFL: 9,9-bis (4-aminophenyl) fluorene (formula (3))
NMP: N-methyl-2-pyrrolidone
Embedded image

[0021]
(Synthesis of PI-1)
In a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, 667.74 g of NMP was charged, and nitrogen gas was flown. Next, 108.16 g (0.37 mol) of APB, which is an amine component, 18.22 g (0.022 mol) of APPS-9, 5.41 g (0.022 mol) of APPS-1 and 7.58 g (0.52 g) of BAFL-1. 022 mol) and stirred until uniform. After uniformly dissolving, 135.04 g (0.435 mol) of ODPA as an acid component was added over 10 minutes while maintaining the system at 20 ° C., followed by stirring for 2 hours to obtain a polyamic acid solution. During this time, the flask was kept at 20 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with toluene was attached to the flask, and 74.193 g of toluene was added to the system. The generated water was discharged outside the system while maintaining the reflux state by heating the system to the reflux temperature in an oil bath. After heating for 3 hours, the mixture was cooled to obtain a polyimide resin solution PI-1.
[0022]
(Synthesis of PI-2)
In a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, 661.48 g of NMP was charged, and nitrogen gas was flown. Next, 43.85 g (0.15 mol) of APB, which is an amine component, 62.8 g (0.075 mol) of APPS-9, 18.6 g (0.075 mol) of APPS-1, and 26.13 g (0.15 mol) of BAFL-1. 075 mol) and stirred until uniform. After dissolving uniformly, 116.33 g (0.375 mol) of ODPA as an acid component was added over 10 minutes while maintaining the system at 20 ° C., and then stirring was continued for 2 hours to obtain a polyamic acid solution. During this time, the flask was kept at 20 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with toluene was attached to the flask, and 72.39 g of toluene was added to the system. The generated water was discharged outside the system while maintaining the reflux state by heating the system to the reflux temperature in an oil bath. After heating for 3 hours, the mixture was cooled to obtain a polyimide resin solution PI-2.
[0023]
(Synthesis of PI-3)
950 g of NMP was put into a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, a thermometer, and a stirrer, and nitrogen gas was flown. Next, the amine components APB 10.23 (0.035 mol) and BAPP 50.29 g (0.123 mol), APPS-9 58.59 g (0.07 mol), and APPS-1 17.4 g (0. 07 mol) and 18.29 g (0.053 mol) of BAFL were added, and the mixture was stirred until it became uniform. After uniformly dissolving, 108.58 g (0.035 mol) of ODPA as an acid component was added over 10 minutes while maintaining the system at 20 ° C., followed by stirring for 2 hours to obtain a polyamic acid solution. During this time, the flask was kept at 20 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with toluene was attached to the flask, and 71.2 g of toluene was added to the system. The generated water was discharged outside the system while maintaining the reflux state by heating the system to the reflux temperature in an oil bath. After heating for 3 hours, the mixture was cooled to obtain a polyimide resin solution PI-3.
[0024]
(Synthesis of PI-4)
In a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, 678.74 g of NMP was charged, and nitrogen gas was flown. Next, 116.93 g (0.40 mol) of APB, which is an amine component, 18.60 g (0.022 mol) of APPS-9, and 5.41 g (0.022 mol) of APPS-1 were added and stirred until uniform. did. After uniformly dissolving, 137.87 g (0.444 mol) of ODPA as an acid component was added over 10 minutes while maintaining the system at 20 ° C., followed by stirring for 2 hours to obtain a polyamic acid solution. During this time, the flask was kept at 20 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with toluene was attached to the flask, and 75.42 g of toluene was added to the system. The generated water was discharged outside the system while maintaining the reflux state by heating the system to the reflux temperature in an oil bath. After heating for 3 hours, the mixture was cooled to obtain a polyimide resin solution PI-4.
[0025]
(Synthesis of PI-5)
In a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, 694.55 g of NMP was charged, and nitrogen gas was flown. Next, 143.68 g (0.350 mol) of BAPP, which is an amine component, 16.28 g (0.019 mol) of APPS-9, and 4.83 g (0.019 mol) of APPS-1 were added until the mixture became uniform. Stirred. After uniformly dissolving, 120.64 g (0.389 mol) of ODPA as an acid component was added over 10 minutes while maintaining the system at 20 ° C., followed by stirring for 2 hours to obtain a polyamic acid solution. During this time, the flask was kept at 20 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with toluene was attached to the flask, and 77.17 g of toluene was added to the system. The generated water was discharged outside the system while maintaining the reflux state by heating the system to the reflux temperature in an oil bath. After heating for 3 hours, the mixture was cooled to obtain a polyimide resin solution PI-5.
[0026]
Table 1 shows the mixing ratio of the polyimide resin solutions PI-1 to PI-5 obtained above. The blending values in Table 1 indicate the molar ratio. The polyimide resin solutions PI-1 to PI-5 are applied to a silicone release-treated biaxially stretched polyester film by a roll coater so that the thickness becomes 25 μm, 2 minutes at 80 ° C., 2 minutes at 130 ° C., 2 minutes at 180 ° C. Drying was performed to obtain a 25-μm-thick film adhesive supported on a polyester film. The glass transition temperature and the coefficient of linear thermal expansion of this film adhesive were measured. Table 1 shows the results.
[0027]
Glass transition temperature / coefficient of linear thermal expansion: A film adhesive was cut into a rectangle having a thickness of 25 μm and a width of 3 mm, and the temperature was raised at a rate of 5 ° C. / And a load of 25 mN. The glass transition temperature (° C.) and the coefficient of linear thermal expansion in a predetermined temperature range [(30 to 70 ° C.), (160 to 170 ° C.)] were calculated from the extrapolated point of the TMA curve using analysis software. Table 1 shows the results.
[0028]
Next, the obtained polyimide resin solution is applied to both surfaces of a commercially available polyimide film (UPILEX 50SGA, Ube Industries, Ltd.) and dried at a temperature of 80 to 230 ° C. to remove the film adhesive carried on the polyimide film. Obtained. The adhesive strength and thermal decomposition temperature of this film adhesive were measured. Table 1 shows the results.
[0029]
Adhesive strength: A film-like adhesive carried on both sides of a polyimide film was thermocompression-bonded to a 42-alloy plate at 300 ° C. to form a test piece, and after releasing the pressure, it was annealed at 300 ° C. for 30 seconds. The pressure applied to the bonding surface was 4 kgf / cm ^{2 as} a result of calculation from the gauge pressure and the bonding area. The peel strength (Nm) at 180 ° C. of this test piece was measured. Table 1 shows the results.
[0030]
Thermal decomposition temperature: About 10 mg of a film adhesive obtained from the film adhesive carried on the polyimide film was precisely weighed, and a thermogravimetric analyzer (TGDTA, manufactured by Seiko Instruments Inc., SS-6000) was used. At a heating rate of 10 ° C./min. The temperature at a weight loss of 5% was calculated as thermal decomposition temperature (° C.) using analysis software. Table 1 shows the results.
[0031]
[Table 1]

[0032]
【The invention's effect】
According to the present invention, even if the glass transition temperature is lowered, the heat resistance does not decrease, the flow property at the time of bonding is excellent, and a film-like adhesive having further excellent storage stability is obtained. As a result, the temperature at the time of bonding the semiconductor element and the lead frame can be set lower than before, so that it is possible to suppress the thermal shock to the members in the semiconductor device assembling process, and to obtain a highly reliable semiconductor device. it can.

Claims (3)

In an assembling process of a semiconductor device, an adhesive for bonding a semiconductor element and a lead frame includes at least one diamine compound selected from diaminopolysiloxane, aromatic diamine or aliphatic diamine represented by the general formula (1) and an aromatic compound. polyimide obtained by reacting a tetracarboxylic acid anhydride, and of all -HN-R-NH- (residues R are obtained by removing two NH ₂ diamine compound), represented by the formula (2) A film-like adhesive carried on a base material, which is obtained by casting a polyimide resin having a structure of 1 mol% or more on the base material.

(Wherein, R ₁ and R ₂ represent a divalent aliphatic group or an aromatic group having 1 to 4 carbon atoms, and R ₃ , R ₄ , R ₅ and R ₆ represent a monovalent aliphatic group or an aromatic group. And k is an integer of 1 to 100.)

A lead frame with a film adhesive, wherein the film adhesive carried on the base material according to claim 1 is adhered to a lead frame. A semiconductor device comprising the lead frame with a film adhesive according to claim 2.