JP2004186593A - Low dielectric insulating film, its manufacturing method, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low dielectric insulating film which enables formation of an insulating film of a high strength and a low dielectric constant, its manufacturing method, and a semiconductor device using the low dielectric constant insulating film. <P>SOLUTION: The manufacturing method of the low dielectric insulating film comprises a siloxane resin film formation process for forming a siloxane resin film by applying a low dielectric insulating film formation material containing a siloxane resin on a substrate, a surface treatment process for making the surface of the siloxane resin film hydrophilic by means of surface treatment liquid and a baking process for baking the siloxane resin film which is subjected to surface treatment. In the manufacturing method, an embodiment wherein the surface treatment liquid is selected from an organic solvent with a hydroxyl group and water solution of pH 1 to 10, an embodiment wherein insolubilization treatment is carried out for insolubilizing the surface treatment liquid by heat-treating the siloxane resin film before the surface treatment process, or the like are preferable. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１９】
前記一般式（１）において、Ｒ^１〜Ｒ^３は、互いに同一であってもよいし、異なっていてもよい、水素原子、フッ素原子、−Ｏ−、又は置換基を表す。ｍは、５〜２００の整数を表し、好ましくは１０〜１００の整数を表す。
【００２０】
【化４】
一般式（２）

【００２１】
前記一般式（２）において、Ｒ^４〜Ｒ^７の内、少なくとも１つは水素原子であり、その他は互いに同一であってもよいし、異なっていてもよい、水素原子、フッ素原子、又は置換基を表す。ｎは、５〜２００の整数を表し、好ましくは１０〜１００の整数を表す。
【００２２】
前記一般式（１）及び（２）において、置換基は、アルキル基、エーテル結合又はエステル結合を有する基を示す。アルキル基としては、炭素数１〜１０のものが好ましく、例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｎ−ヘキシル基、イソヘキシル基、ｎ−ヘプチル基、ｎ−オクチル基、イソオクチル基、ｎ−デシル基、イソデシル基等が挙げられる。
前記エーテル結合又はエステル結合を有する基は、炭素数１〜１０、特に１〜５のものが好ましい。前記エーテル結合（Ｃ−Ｏ−Ｃ）を有する基において、エーテル結合は１又は２以上を有していてもよい。前記エステル結合（ＣＯＯ）を有する基において、エステル結合は１又は２以上を有していてもよい。
【００２３】
前記シロキサン樹脂としては、具体的には、シラン化合物をゾルゲル法により製造したシロキサン樹脂（例えば、テトラアルコキシシランのゾルゲルポリマー、トリアルコキシシランのゾルゲルポリマー、メチルトリアルコキシシランのゾルゲルポリマー、テトラアルコキシシラン及びトリアルコキシシランのゾルゲルポリマー、テトラアルコキシシラン及びメチルトリアルコキシシランのゾルゲルポリマー、メチルトリアルコキシシラン及びトリアルコキシシランのゾルゲルポリマー、テトラアルコキシシラン及びジメチルアルコキシシランのゾルゲルポリマーなど）、メチルシルセスキオキサン樹脂、水素シルセスキオキサン樹脂、フッ素シルセスキオキサン樹脂、フッ素含有水素シルセスキオキサン樹脂、フッ素含有メチルシルセスキオキサン樹脂、などが挙げられる。
【００２４】
前記シラン化合物としては、例えば、テトラアルコキシシラン、トリアルコキキシシラン、メチルトリアルコキシシラン、エチルトリアルコキシシラン、プロピルトリアルコキシシラン、フェニルトリアルコキシシラン、ビニルトリアルコキシシラン、アリルトリアルコキシシラン、グリシジルトリアルコキシシラン、ジアルコキキシシラン、ジメチルジアルコキシシラン、ジエチルジアルコキシシラン、ジプロピルジアルコキシシラン、ジフェニルジアルコキシシラン、ジビニルジアルコキシシラン、ジアリルジアルコキシシラン、ジグリシジルジアルコキシシラン、フェニルメチルジアルコキシシラン、フェニルエチルジアルコキシシラン、フェニルプロピルトリアルコキシシラン、フェニルビニルジアルコキシシラン、フェニルアリルジアルコキシシラン、フェニルグリシジルジアルコキシシラン、メチルビニルジアルコキシシラン、エチルビニルジアルコキシシラン、プロピルビニルジアルコキシシラン、などが挙げられ、これらは、１種単独で使用してもよいし、２種以上を併用してもよい。
【００２５】
−その他の成分−
前記その他の成分としては、前記シロキサン樹脂が溶解可能な希釈溶剤、熱分解性樹脂、等が挙げられる。
前記希釈溶剤としてはシロキサン樹脂及びポリカルボシランが溶解すれば特に限定されず、例えば、シクロヘキサノン、メチルイソブチルケトン、メチルエチルケトン、メチルセロソルブ、エチルセロソルブ、オクタン、デカン、プロピレングリコール、プロピレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテルアセテート、等が挙げられ、これらは、１種単独で使用してもよいし、２種以上を併用してもよい。
【００２６】
前記熱分解性樹脂としては、１５０〜３５０℃の熱分解温度を有するものが好ましく、例えば、ポリスチレン、アクリル系重合体、スチレンーアクリル共重合体、塩素化ポリエチレン、ポリプロピレン、アイオノマー等のオレフィン系重合体、ポリ塩化ビニル、ポリエステル、ポリアミド、ポリウレタン、エポキシ樹脂、ジアリルフタレート樹脂、シリコーン樹脂、ケトン樹脂、ポリビニルブチラール樹脂等のポリビニルアセタール樹脂、フェノール樹脂、ロジン変性フェノール樹脂、キシレン樹脂、ロジン変性マレイン酸樹脂、ロジンエステル、石油樹脂など各種重合体が挙げられる。
【００２７】
前記シロキサン樹脂の重量平均分子量（Ｍｗ）としては、５００〜５０，０００，０００が好ましく、７，０００〜４８，０００，０００がより好ましい。
前記重量平均分子量（Ｍｗ）が、５００未満であると、沸点が低く、熱処理時に、熱分解性基と共に分解・脱離してしまうことがある一方、５０，０００，０００を超えると、希釈溶剤への溶解性が悪いことがある。
【００２８】
前記シロキサン樹脂の前記低誘電率絶縁膜形成材料における含有量としては、２０〜８０質量％が好ましく、３０〜７０質量％がより好ましい。
【００２９】
前記低誘電率絶縁膜形成材料の製法としては、特に制限はなく、目的に応じて適宜選択することができるが、例えば、前記シラン化合物等を前記希釈溶剤に溶解させた後、該シラン化合物を重合する高分子化触媒を添加する方法、等が挙げられる。
【００３０】
前記高分子化触媒としては、例えば、１分子中に脂肪族、脂環族及び芳香族の少なくともいずれかの炭化水素を含んでいる化合物が好ましく、具体的には、マレイン酸、酢酸、スルホン酸、トルエンスルホン酸等の有機酸化合物、ピリジン、トリエチルアミン等の有機アルカリ化合物、などが挙げられる。これらは、１種単独で使用してもよく、２種以上を併用してもよい。
前記高分子化触媒として、前記有機酸化合物や前記有機アルカリ化合物を用いることにより、低誘電率絶縁膜を形成する際に、シリカ分子の構造欠陥の発生が更に抑制されるため好ましい。また、前記高分子化触媒として、前記有機アルカリ化合物を用いることにより、低誘電率絶縁膜の形成の際、高密度シリカが形成されるため、膜強度低下が効果的に抑制される。
【００３１】
−塗布方法−
前記塗布の方法としては、特に制限はなく、公知の塗布方法、例えば、スピンコート法、ディップコート法、ニーダーコート法、カーテンコート法、ブレードコート法、スキャン塗布法、等が挙げられる。これらの中でも、塗布効率等の点で、スピンコート法、ディップコート法、等が好ましい。
前記塗布の後、必要に応じて溶媒等を乾燥させることができ、該乾燥の温度としては、特に制限はなく、目的に応じて適宜選択することができるが、１００〜２５０℃程度が好ましい。なお、後述するように、シロキサン樹脂被膜の不溶化を熱処理で行う場合には、前記乾燥の熱処理と同時に行うことができる。
【００３２】
＜表面処理工程＞
前記表面処理工程は、該シロキサン樹脂被膜に対し、水酸基を有する有機溶剤及びｐＨ１〜１０の水溶液から選ばれる表面処理液でその表面を親水性化する。
【００３３】
−水酸基を有する有機溶剤−
前記水酸基を有する有機溶剤としては、特に制限はされないが、好ましくは一分子中に１個以上の水酸基を有するメチルアルコール、エチルアルコール、プロピルアルコール、イソプロピルアルコール、ブチルアルコール、イソブチルアルコール、ｔｅｒｔ−ブチルアルコール等のアルコール系、フェノール、クレゾール、ジエチルフェノール、トリエチルフェノール、プロピルフェノール、ノニルフェノール、ビニルフェノール、アリルフェノール、ノニルフェノール等のフェノール系などが挙げられる。なお、前記水酸基を有する有機溶剤には水を添加しても構わない。
【００３４】
−ｐＨ１〜１０の水溶液−
前記ｐＨ１〜１０の水溶液としては、特に制限されないが、例えば、塩酸水溶液，硝酸水溶液，硫酸水溶液等の酸性水溶液；マレイン酸水溶液、蟻酸水溶液、酢酸水溶液、トルエンスルホン酸水溶液等の有機酸水溶液；アンモニア水溶液等のアルカリ水溶液；ジメチルアミン、プロピルアミン、ヘキサメチルアミン、シクロヘキシルアミン、ジシクロヘキシルアミン、テトラメチルアンモニウムハイドロキサイト等の有機アルカリ系水溶液、などが挙げられる。なお、ｐＨが１０を超える水溶液により表面処理を行うとシロキサン樹脂が分解する場合があり、好ましくない。
【００３５】
前記表面処理液で表面処理する方法としては、特に制限はなく、例えば、シロキサン樹脂被膜をスピンコートした後にピペット又はスピンコータのノズルから被膜上に滴下する方法、などが挙げられる。
【００３６】
前記シロキサン樹脂被膜に表面処理を行う際、シロキサン樹脂被膜が表面処理液に溶解してしまう場合は、表面処理工程の前に、シロキサン樹脂被膜を表面処理液に対し不溶化する不溶化処理を行うことが好ましい。
前記不溶化処理としては、熱処理、光照射、電子線照射、が挙げられ、これらの中でも、熱処理が簡便かつ低コストである点で好ましい。
前記不溶化処理として熱処理を行う場合、酸素１％以上含む雰囲気で、かつ、１００〜４００℃、好ましくは１００〜３００℃で行うとよい。これは、１００℃未満では不溶化しづらく、一方、４００℃を超えると酸化により低誘電率絶縁膜にダメージを与えるためである。
前記シロキサン樹脂被膜形成工程におけるシロキサン樹脂被膜の乾燥、及びシロキサン樹脂被膜の不溶化が、熱処理により同時に行うことが製造効率を高める点で好ましい。
【００３７】
＜焼成工程＞
前記焼成工程は、表面処理されたシロキサン樹脂被膜を焼成する。
前記焼成は、不活性雰囲気、真空雰囲気及び酸素を１０ｐｐｍ以上含む雰囲気から選ばれる雰囲気中で、２００〜５００℃で行われることが好ましい。特に、酸素１０ｐｐｍ以上の雰囲気中で、５００℃以上で行うと、低誘電率絶縁膜が酸化して誘電率上昇を図ることができる。
【００３８】
（低誘電率絶縁膜）
前記低誘電率絶縁膜は、前記本発明の低誘電率絶縁膜の製造方法により製造される。
前記低誘電率絶縁膜は、誘電率が３．０以下であり、２．８以下が好ましい。ここで、前記誘電率は、低誘電率絶縁膜上に金電極を作製し、誘電率測定器により測定することができる。
前記低誘電率絶縁膜は、弾性率が５．５ＧＰａ以上であり、７．０ＧＰａ以上が好ましく、８．０ＧＰａ以上がより好ましい。
ここで、前記弾性率は、ナノインデンターを用いて測定することができる。
前記低誘電率絶縁膜に形成された孔（空隙）の径（平均径）としては、特に制限はなく、目的に応じて適宜選択することができるが、低誘電率特性に優れる点で、１０ｎｍ以下が好ましく、８ｎｍ以下がより好ましい。
なお、前記孔の径（平均径）は、透過型顕微鏡（ＴＥＭ）により観察し測定することができる。
前記低誘電率絶縁膜の厚みとしては、特に制限はなく、目的に応じて適宜選択することができるが、５０〜３０００ｎｍ程度が好ましい。
【００３９】
本発明では、特にシロキサン樹脂に熱分解樹脂や熱分解性官能基を含む多孔質膜を形成する場合に高密度なシリカを形成できることから、低誘電率でかつ耐湿性、機械的強度の高い低誘電率絶縁膜を形成できる。したがって、本発明により形成された被膜は半導体装置の低誘電率層間絶縁膜として有効であり、この絶縁膜を用いればデバイスの応答速度の速い半導体集積回路が得られる。
【００４０】
（半導体装置）
本発明の半導体装置は、本発明の低誘電率絶縁膜を層間絶縁膜として有すること以外には特に制限はなく、目的に応じて適宜選択した部材等を有してなる。本発明の半導体装置の具体例としては、フラッシュメモリ、ＤＲＡＭ、ＦＲＡＭ、ＭＯＳトランジスタ、などが好適に挙げられる。
本発明の半導体装置は、本発明の低誘電率絶縁膜を層間絶縁膜として有するため、各層の層間の絶縁性に優れ、高速で信頼性が高い。
【００４１】
以下に、本発明の半導体装置の一例について、図１を参照しながら説明する。本発明の半導体装置は、例えば以下のようにして得られる。即ち、図１に示すように、先ず素子間分離膜２で分離され、ソース拡散層５ａ、ドレイン拡散層５ｂ、及び、サイドウォール絶縁膜３を有するゲート電極４を形成したトランンジスタ層が形成されたシリコンウエハ１上に、層間絶縁膜（リンガラス）６及びストッパー膜７を形成し、電極取り出し用のコンタクトホールを形成する。このコンタクトホールに、スパッタ法でバリア膜８（ＴｉＮ；５０ｎｍ）を形成した後、ＷＦ_６及び水素を混合し還元することで導体プラグ（Ｗ）９を埋め込み、化学的機械研磨法（ＣＭＰ）によりビア以外の部分を除去する。
【００４２】
続いて、ストッパー膜７上に、本発明の低誘電率絶縁膜の製造方法により低誘電率絶縁膜１０（厚み：４５０ｎｍ）を形成した後、ＴＥＯＳ−ＳｉＯ_２（キャップ膜１２）を５０ｎｍ積層させる。このキャップ膜１２を、１層目配線パターンを施したレジスト層をマスクとして、ＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマによって加工する。
【００４３】
この配線溝に、Ｃｕの絶縁層への拡散バリアとして働くバリア膜８（ＴｉＮ）（５０ｎｍ）と、電解メッキの際に電極として働くシード層Ｃｕ（５０ｎｍ）とを、スパッタにより形成する。更に、電解メッキにより銅（６００ｎｍ）を積層した後、化学的機械研磨法（ＣＭＰ）により配線パターン部以外のメタルを除去し、銅配線１４の層を形成する。
【００４４】
次に、ビア層及び配線層を同時に形成するデュアルダマシン法について説明する。第１層目配線層上に、Ｃｕ拡散防止を目的として、シラン及びアンモニアガスを用い、プラズマＣＶＤにより、拡散防止膜１３としてＳｉＮ膜（５０ｎｍ）を形成し、本発明の低誘電率絶縁膜の製造方法により低誘電率絶縁膜１０（５０ｎｍ）を積層する。配線層部分に、シラン及びアンモニアガスを用い、プラズマＣＶＤにより、ストッパー膜７としてＳｉＮ膜（５０ｎｍ）を成膜し、更に、本発明の低誘電率絶縁膜の製造方法により低誘電率絶縁膜１０（４００ｎｍ）を形成する。キャップ膜１２（５０ｎｍ）として、ＴＥＯＳ−ＳｉＯ_２膜を積層する。この低誘電率絶縁膜１０に、ビアパターンを形成したレジスト層をマスクとして、ＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマにより、ガス組成を変えることでＳｉＯ_２／低誘電率絶縁膜／ＳｉＮ／低誘電率絶縁膜／ＳｉＮの順に加工する。続いて、第２層目目配線パターンを施したレジスト層をマスクとして、ＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマにより加工する。このビアと配線溝に、Ｃｕの絶縁層への拡散バリアとして働くバリア膜８（ＴｉＮ；５０ｎｍ）、及び、電解メッキの際に電極として働くシード層Ｃｕ（５０ｎｍ）をスパッタにより形成する。更に、電解メッキにより銅（１４００ｎｍ）を積層した後、ＣＭＰにより配線パターン部以外のメタルを除去し、銅配線１４を形成した化学的機械研磨法（ＣＭＰ）によりビア以外の部分を除去しビア層を形成する。これにより、前記工程を繰り返して、３層配線を形成することができる。このようにして、得られる多層配線において、１００万個の連続ビアの歩留まりを９０％以上とすることができる。
【００４５】
【実施例】
以下、本発明の実施例を説明するが、本発明は、これらの実施例に何ら限定されるものではない。
【００４６】
（製造例１）
−低誘電率絶縁膜形成材料の作製−
テトラエトキシシラン ２０．８ｇ（０．１ｍｏｌ）、メチルトリエトキシシラン １７．８ｇ（０．１ｍｏｌ）、グリシドキシプロピルトリメトキシシラン２３．６ｇ（０．１ｍｏｌ）、及びメチルイソブチルケトン３９．６ｇを、２００ｍｌの反応容器に仕込み、１質量％のテトラメチルアンモニウムハイドロキサイド水溶液を１６．２ｇ（０．９ｍｏｌ）を１０分間で滴下し、滴下終了後２時間の熟成反応を行った。
次に、硫酸マグネシウム５ｇを添加し、過剰の水分を除去した後、ロータリーエバポレータにて熟成反応により生成したエタノールを反応溶液が５０ｍｌになるまで除去した。得られた反応溶液にメチルイソブチルケトンを２０ｍｌ添加し、２００℃のオーブンによりメチルイソブチルケトンを除去した。
得られた製造例１の低誘電率絶縁膜形成材料の固形分濃度は１８．２質量％（シロキサン樹脂の重量平均分子量；１７２，０００）であった。
【００４７】
（製造例２）
−低誘電率絶縁膜形成材料の作製−
テトラエトキシシラン２０．８ｇ（０．１ｍｏｌ）、トリエトキシシラン１６．１ｇ（０．１ｍｏｌ）、グリシドキシプロピルトリメトキシシラン２３．６ｇ（０．１ｍｏｌ）、及びメチルイソブチルケトン３９．６ｇを、２００ｍｌの反応容器に仕込み、１質量％のテトラメチルアンモニウムハイドロキサイド水溶液１６．２ｇ（０．９ｍｏｌ）を１０分間で滴下し、滴下終了後２時間の熟成反応を行った。
次に、硫酸マグネシウム５ｇを添加し、過剰の水分を除去した後、ロータリーエバポレータにて熟成反応により生成したエタノールを反応溶液が５０ｍｌになるまで除去した。得られた反応溶液にメチルイソブチルケトンを２０ｍｌ添加し、２００℃のオーブンによりメチルイソブチルケトンを除去した。
得られた製造例２の低誘電率絶縁膜形成材料の固形分濃度は１５．４質量％（シロキサン樹脂の重量平均分子量；２６０，０００）であった。
【００４８】
（製造例３）
−低誘電率絶縁膜形成材料の作製−
窒素ガス導入管、液体用定量ポンプを装備した反応容器に硫酸８８ｇ（０．９ｍｏｌ）、発煙硫酸（６０％ＳＯ_４）３３ｇを仕込み、トルエン８７ｇ（０．９５ｍｏｌ）を定量ポンプにて２ｍｌ／ｍｉｎの条件で滴下し、滴下終了後１時間の熟成反応を行った。
次に、トリクロロシラン４１ｇ（０．３ｍｏｌ）をトルエンに２０質量％に稀釈した原料溶液を定量ポンプにて２ｍｌ／ｍｉｎで滴下し、滴下終了後に２時間熟成反応を行った。反応終了後、５０質量％硫酸水溶液を１００ｍｌ添加し、沈殿したトルエンスルホン酸をろ過した後、分液ロートにて過剰の硫酸水を除去した。
この溶液に炭酸カルシウム２ｇで残留した硫酸を中和し、硫酸マグネシウム５ｇで脱水した後、ロータリーエバポレータを用いてトルエンを完全に除去することで水素シルセスキオキサン樹脂の固形物を１５ｇ得た（重量平均分子量；４８００）。
得られた水素シルセスキオキサン樹脂をメチルイソブチルケトン７０ｇに溶解させ、固形分濃度１７．５％の溶液（製造例３の低誘電率絶縁膜形成材料）を作製した。
【００４９】
（製造例４）
−低誘電率絶縁膜形成材料の作製−
窒素ガス導入管、液体用定量ポンプを装備した反応容器に硫酸８８ｇ（０．９ｍｏｌ）、発煙硫酸（６０％ＳＯ_４）３３ｇを仕込み、トルエン８７ｇ（０．９５ｍｏｌ）を定量ポンプにて２ｍｌ／ｍｉｎの条件で滴下し、滴下終了後１時間の熟成反応を行った。
次に、トリクロロシラン３６ｇ（０．２７ｍｏｌ）、及びフルオロトリクロロシラン４．６ｇを、トルエンに２０質量％に稀釈した原料溶液を定量ポンプにて２ｍｌ／ｍｉｎで滴下し、滴下終了後に２時間熟成反応を行った。反応終了後、５０質量％硫酸水溶液を１００ｍｌ添加し、沈殿したトルエンスルホン酸をろ過した後、分液ロートにて過剰の硫酸水を除去した。
この溶液に炭酸カルシウム２ｇで残留した硫酸を中和し、硫酸マグネシウム５ｇで脱水した後、ロータリーエバポレータを用いてトルエンを完全に除去することで水素シルセスキオキサン樹脂の固形物を１５ｇ得た（重量平均分子量；３９００）。
得られた水素シルセスキオキサン樹脂をメチルイソブチルケトン７０ｇに溶解させ、固形分濃度１７．５％の溶液（製造例４の低誘電率絶縁膜形成材料）を作製した。
【００５０】
（実施例１）
−低誘電率絶縁膜の形成−
製造例１より作製した低誘電率絶縁膜形成材料をＳｉウェハ上に３０００回転、２０秒でスピンコートした後、大気中２００℃で溶剤乾燥を行った。
次いで、イソプロピルアルコールにて表面処理を行った。その後、酸素濃度１００ｐｐｍ以下の窒素雰囲気で４００℃、３０分アニールを行うことで実施例１の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は１．９７であった。また、ナノインデンターにて弾性率を測定したところ、７．２ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、６．３ｎｍであった。
【００５１】
（実施例２）
−低誘電率絶縁膜の形成−
実施例１において、表面処理を行う溶液としてｐＨ８のアンモニア水溶液を用いた以外は同様の手法で実施例２の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．０１であった。また、ナノインデンターにて弾性率を測定したところ、７．８ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．２ｎｍであった。
【００５２】
（比較例１）
−低誘電率絶縁膜の形成−
実施例１において、表面処理を行わない以外は同様の手法で比較例１の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は１．９８であった。また、ナノインデンターにて弾性率を測定したところ、４．４ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、８．９ｎｍであった。
【００５３】
（実施例３）
−低誘電率絶縁膜の形成−
製造例２より作製した低誘電率絶縁膜形成材料をＳｉウェハ上に３０００回転、２０秒でスピンコートした後、大気中２００℃で溶剤乾燥を行った。
次いで、イソプロピルアルコールにて表面処理を行った。その後、酸素濃度１００ｐｐｍ以下の窒素雰囲気で４００℃、３０分アニールを行うことで実施例３の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は１．９５であった。また、ナノインデンターにて弾性率を測定したところ、８．０ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．８ｎｍであった。
【００５４】
（実施例４）
−低誘電率絶縁膜の形成−
実施例３において、表面処理を行う溶液としてｐＨ８のアンモニア水溶液を用いた以外は同様の手法で実施例４の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は１．９８であった。また、ナノインデンターにて弾性率を測定したところ、８．２ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．６ｎｍであった。
【００５５】
（比較例２）
−低誘電率絶縁膜の形成−
実施例３において、表面処理を行わない以外は同様の手法で比較例２の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は１．９９であった。また、ナノインデンターにて弾性率を測定したところ、４．９ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、８．２ｎｍであった。
【００５６】
（実施例５）
−低誘電率絶縁膜の形成−
製造例３により作製した低誘電率絶縁膜形成材料をＳｉウェハ上に３０００回転、２０秒でスピンコートした後、大気中２００℃で溶剤乾燥を行った。
次いで、イソプロピルアルコールにて表面処理を行った。その後、酸素濃度１００ｐｐｍ以下の窒素雰囲気で４００℃、３０分アニールを行うことで実施例５の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．７２であった。また、ナノインデンターにて弾性率を測定したところ、８．６ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．４ｎｍであった。
【００５７】
（実施例６）
−低誘電率絶縁膜の形成−
実施例５において、表面処理を行う溶液としてｐＨ８のアンモニア水溶液を用いた以外は同様の方法で実施例６の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．６６であった。また、ナノインデンターにて弾性率を測定したところ、１０ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．５ｎｍであった。
【００５８】
（比較例３）
−低誘電率絶縁膜の形成−
実施例５において、表面処理を行わない以外は同様の方法で比較例３の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．８５であった。また、ナノインデンターにて弾性率を測定したところ、５．４ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．６ｎｍであった。
【００５９】
（実施例７）
−低誘電率絶縁膜の形成−
製造例４より作製した低誘電率絶縁膜形成材料をＳｉウェハ上に３０００回転、２０秒でスピンコートした後、大気中２００℃で溶剤乾燥を行った。
次いで、イソプロピルアルコールにて表面処理を行った。その後、酸素濃度１００ｐｐｍ以下の窒素雰囲気で４００℃、３０分アニールを行うことで実施例７の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．４６であった。また、ナノインデンターにて弾性率を測定したところ、７．８ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、７．４ｎｍであった。
【００６０】
（実施例８）
−低誘電率絶縁膜の形成−
実施例７において、表面処理を行う溶液としてｐＨ８のアンモニア水溶液を用いた以外は、同様の方法で実施例８の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．４５であった。また、ナノインデンターにて弾性率を測定したところ、９．５ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、８．６ｎｍであった。
【００６１】
（比較例４）
−低誘電率絶縁膜の形成−
実施例７において、表面処理を行わない以外は、同様の方法で比較例４の低誘電率絶縁膜を形成した。
得られた低誘電率絶縁膜上に１ｍｍφの金電極を作製し、誘電率を測定したところ、誘電率は２．４９であった。また、ナノインデンターにて弾性率を測定したところ、５．１ＧＰａであった。結果を表１に示す。更に、透過型顕微鏡（ＴＥＭ）により平均孔径を測定したところ、８．３ｎｍであった。
【００６２】
【表１】

【００６３】
（実施例９）
−半導体装置の作製−
本発明の低誘電率絶縁膜の製造方法により製造された本発明の低誘電率絶縁膜を備えた本発明の半導体装置を以下のようにして得た。
即ち、図１に示すように、まず、素子間分離膜２で分離され、ソース拡散層５ａとドレイン拡散層５ｂ、サイドウォール絶縁膜３を有するゲート電極を形成したトランンジスタ層が形成されたＳｉウェハ１に層間絶縁膜６、ストッパー膜７を形成し、電極取り出し用のコンタクトホールを形成した。このコンタクトホールにスパッタ法でＴｉＮ ８を５０ｎｍ形成した後、ＷＦ_６及び水素を混合し、還元することで導体プラグ（Ｗ）９を埋め込み、化学的機械研磨法（ＣＭＰ）によりビア以外の部分を除去した。
【００６４】
続いて、実施例１と同様の方法で本発明による低誘電率絶縁膜１０をＳｉ平板上４５０ｎｍとなる条件での成膜を行った後にキャップ膜としてＴＥＯＳ−ＳｉＯ_２ １２を５０ｎｍ積層させた。このキャップ膜１２に１層目配線パターンを施したレジスト層をマスクにＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマにより加工した。
【００６５】
この配線溝に、Ｃｕの絶縁層への拡散バリアとして働くＴｉＮ ８を５０ｎｍと電解メッキの際に電極として働くシード層Ｃｕ（５０ｎｍ）をスパッタにより形成した。更に、電解メッキによりＣｕ１４を６００ｎｍ積層した後、化学的機械研磨法（ＣＭＰ）により配線パターン部以外のメタルを除去し、配線層を形成した。
【００６６】
次に、ビア層と配線層を同時に形成するデュアルダマシン法について説明する。第１層目配線層上にＣｕ拡散防止を目的としてシランとアンンモニアガスを用いてプラズマＣＶＤにより拡散防止膜としてＳｉＮ膜 １３を５０ｎｍ、実施例１と同様の方法で低誘電率絶縁膜１０を６５０ｎｍ積層する。配線層部分に、シランとアンンモニアガスを用いてプラズマＣＶＤによりストッパ膜としてＳｉＮ膜７を５０ｎｍと実施例１と同様の方法で低誘電率絶縁膜１０をＳｉ平板上４０ｎｍなる条件で成膜を行った後にキャップ膜としてＴＥＯＳ−ＳｉＯ_２（１２）を５０ｎｍ積層した。この絶縁層にビアパターンを形成したレジスト層をマスクにＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマによりガス組成を変えることでＳｉＯ_２／低誘電率絶縁膜／ＳｉＮ／低誘電率絶縁膜／ＳｉＮの順に加工した。つづいて、第２層目配線パターンを施したレジスト層をマスクにＣＦ_４／ＣＨＦ_３ガスを原料としたＦプラズマにより加工した。このビアと配線溝に、Ｃｕの絶縁層への拡散バリアとして働くＴｉＮ８を５０ｎｍと電解メッキの際に電極として働くシード層Ｃｕを５０ｎｍスパッタにより形成した。更に、電解メッキによりＣｕ １４を１４００ｎｍ積層した後、ＣＭＰにより配線パターン部以外のメタルを除去し、配線層を形成した化学的機械研磨法（ＣＭＰ）によりビア以外の部分を除去しビア層を形成した。以下、上記工程を繰り返し、３層配線を形成した。
以上のようにして、得た半導体装置における多層配線では、１００万個の連続ビアの歩留まりを９０％以上とすることができた。
【００６７】
ここで、本発明の好ましい態様を付記すると、以下の通りである。
（付記１） シロキサン樹脂を含有する低誘電率絶縁膜形成材料を基板上に塗布してシロキサン樹脂被膜を形成するシロキサン樹脂被膜形成工程と、該シロキサン樹脂被膜の表面を表面処理液で親水性化する表面処理工程と、該表面処理されたシロキサン樹脂被膜を焼成する焼成工程とを含むことを特徴とする低誘電率絶縁膜の製造方法。
（付記２） 低誘電率絶縁膜形成材料が、１５０〜３５０℃で熱分解する熱分解性基を側鎖に有するシロキサン樹脂を含む付記１に記載の低誘電率絶縁膜の製造方法。
（付記３） 熱分解性基が、エステル結合及びエーテル結合の少なくともいずれかを含む付記２に記載の低誘電率絶縁膜の製造方法。
（付記４） 低誘電率絶縁膜形成材料が、熱分解性樹脂を含有する付記１から３のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記５） シロキサン樹脂が、下記一般式（１）及び（２）の少なくともいずれかで表される付記１から４のいずれかに記載の低誘電率絶縁膜の製造方法。
【化５】
一般式（１）

前記一般式（１）において、Ｒ^１〜Ｒ^３は、互いに同一であってもよいし、異なっていてもよい、水素原子、フッ素原子、−Ｏ−、又は置換基を表す。ｍは、５〜２００の整数を表す。
【化６】
一般式（２）

前記一般式（２）において、Ｒ^４〜Ｒ^７の内、少なくとも１つは水素原子であり、その他は互いに同一であってもよいし、異なっていてもよい、水素原子、フッ素原子、又は置換基を表す。ｎは、５〜２００の整数を表す。
（付記６） 前記一般式（１）における置換基が、アルキル基、又はエーテル結合若しくはエステル結合を有する基である付記５に記載の低誘電率絶縁膜の製造方法。
（付記７） シロキサン樹脂被膜形成工程における低誘電率絶縁膜形成材料の基板上への塗布をスピンコートで行う付記１から６のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記８） 表面処理液が、水酸基を有する有機溶剤及びｐＨ１〜１０の水溶液から選ばれる付記１から７のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記９） 水酸基を有する有機溶剤が、一分子中に１個以上の水酸基を有するアルコール系溶剤及びフェノール系溶剤のいずれかである付記８に記載の低誘電率絶縁膜の製造方法。
（付記１０）ｐＨ１〜１０の水溶液が、無機酸水溶液、有機酸水溶液、アルカリ水溶液及び有機アルカリ水溶液のいずれかである付記８に記載の低誘電率絶縁膜の製造方法。
（付記１１） 表面処理工程の前に、シロキサン樹脂被膜を表面処理液に対し不溶化する不溶化処理を行う付記１から１０のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記１２） 不溶化処理が、熱処理、光照射及び電子線照射のいずれかである付記１１に記載の低誘電率絶縁膜の製造方法。
（付記１３） 表面処理工程の前に、シロキサン樹脂被膜を熱処理して表面処理液に対し不溶化する不溶化処理を行う付記１から１２のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記１４） シロキサン樹脂被膜形成工程におけるシロキサン樹脂被膜の形成及び不溶化処理が、熱処理により同時に行われる付記１３から１４のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記１５） 熱処理が、酸素を１％以上含む雰囲気中で、１００〜４００℃で行われる付記１２から１４のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記１６） 焼成が、不活性雰囲気、真空雰囲気及び酸素を１０ｐｐｍ以上含む雰囲気から選ばれる雰囲気中で、２００〜５００℃で行われる付記１から１５のいずれかに記載の低誘電率絶縁膜の製造方法。
（付記１７） 付記１から１６のいずれかに記載の低誘電率絶縁膜の製造方法により製造されることを特徴とする低誘電率絶縁膜。
（付記１８） 誘電率が３．０以下であり、かつナノインデンターで測定した弾性率が５．５ＧＰａ以上である付記１７に記載の低誘電率絶縁膜。
（付記１９） 低誘電率絶縁膜に形成された孔の平均径が、１０ｎｍ以下である付記１７又は１８に記載の低誘電率絶縁膜。
（付記２０） 付記１７から１９のいずれかに記載の低誘電率絶縁膜を層間絶縁膜として有することを特徴とする半導体装置。
【００６８】
【発明の効果】
本発明によると、従来における前記問題を解決することができ、機械的強度の高い低誘電率絶縁膜及びその製造方法、並びに、該低誘電率絶縁膜を用いた高速で信頼性の高い半導体装置を提供することができる。
【図面の簡単な説明】
【図１】図１は、本発明の低誘電率絶縁膜を用いた本発明の半導体装置の一例を示す概略説明図である。
【符号の説明】
１・・・シリコンウエハ
２・・・素子間分離膜
３・・・サイドウォール絶縁膜
４・・・ゲート電極
５ａ・・ソース拡散層
５ｂ・・ドレイン拡散層
６・・・層間絶縁膜（リンガラス）
７・・・ストッパー膜
８・・・バリア膜
９・・・導体プラグ（Ｗ）
１０・・低誘電率絶縁膜
１２・・キャップ膜
１３・・拡散防止膜
１４・・銅配線[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a low-dielectric-constant insulating film suitable for multilayer wiring in a semiconductor integrated circuit that requires a high response speed, a method of manufacturing the same, and a semiconductor device using the low-dielectric-constant insulating film.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with an increase in the degree of integration of semiconductor integrated circuits and an increase in element density, a demand for a multilayered semiconductor element has been particularly increased. As the integration density of the semiconductor integrated circuit increases, the distance between the wirings is further narrowed, so that a wiring delay due to an increase in capacitance between the wirings has become a problem. Here, the wiring delay (T) is expressed by the following equation (1), T∝CR... Equation (1), and is affected by the wiring resistance (R) and the capacitance (C) between the wirings. . The relationship between the dielectric constant (ε) and the capacitance (C) between the wirings is given by the following equation (2), C = ε ₀ ε _r S / d is represented by equation (2). In the above equation (2), S is the electrode area, ε ₀ Is the dielectric constant of vacuum, ε _r Represents the dielectric constant of the insulating film, and d represents the wiring interval.
[0003]
The capacitance (C) between the wirings can be reduced by reducing the wiring thickness and the wiring area, but when the wiring thickness is reduced, the wiring resistance (R) is further increased, so that the speed is increased. I can't get it. Therefore, in order to reduce the wiring delay (T) and increase the speed, it is effective to reduce the dielectric constant of the insulating film.
[0004]
Conventionally, as the insulating film, generally, silicon dioxide (SiO 2) ₂ ), Silicon nitride (SiN), phosphor silicate glass (PSG), and other inorganic films, and organic polymers such as polyimide.
[0005]
However, CVD-SiO, which is widely used in semiconductor devices, ₂ The dielectric constant of the film is as high as about 4, and the SiOF film, which has been studied as a low dielectric constant CVD film, has a dielectric constant of about 3.3 to 3.5, but has high hygroscopicity and a high dielectric constant. There was a problem that would rise.
[0006]
Further, as a low dielectric constant insulating film, a porous film that is made porous by heating during film formation by adding an organic resin or the like that evaporates or decomposes by heating to an insulating film forming material has been proposed. . However, since the pore size of these porous films is as large as 10 nm or more, if the porosity is increased to reduce the dielectric constant, the hygroscopicity increases, and the dielectric constant increases due to moisture absorption and the film strength decreases. There was a problem that would occur.
On the other hand, an organic polymer film can be cited as a film having excellent moisture resistance. However, since the glass transition point is as low as 200 to 350 ° C. and the coefficient of thermal expansion is high, there is a problem of damage to wiring.
In recent years, various low dielectric constant film materials have been proposed (for example, see Patent Documents 1 and 2). However, technology relating to a low dielectric constant insulating film having excellent mechanical strength and an efficient method for manufacturing the same. Has not been provided yet.
[0007]
[Patent Document 1]
JP-A-2002-284998
[Patent Document 2]
JP 2002-231714 A
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and has as its object to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide a low dielectric constant insulating film having high mechanical strength, a method for manufacturing the same, and a high-speed and highly reliable semiconductor device using the low dielectric constant insulating film.
[0009]
[Means for Solving the Problems]
Means for solving the problem are as described in (Appendix 1) to (Appendix 20) described later.
The method for producing a low dielectric constant insulating film of the present invention includes a siloxane resin film forming step, a surface treatment step, and a firing step. In the method of manufacturing the low dielectric constant insulating film, the surface of the siloxane resin film is made hydrophilic by using a surface treatment liquid in the process of forming the low dielectric constant insulating film, and the siloxane resin film is baked, whereby the siloxane serving as the core is formed. The resin becomes dense, and the mechanical strength of the low dielectric constant insulating film is greatly improved. Therefore, it is possible to solve the problem of the conventional porous coating that the mechanical strength of the low dielectric constant insulating film is low, and to obtain a low dielectric constant and a low dielectric constant excellent in heat resistance, moisture resistance, and mechanical strength. An insulating coating film is obtained.
[0010]
The low dielectric constant insulating film of the present invention is manufactured by the method for manufacturing a low dielectric constant insulating film of the present invention. For this reason, the low dielectric constant insulating film of the present invention has a low dielectric constant, and is excellent in heat resistance, moisture resistance, and mechanical strength, and thus is suitable as an interlayer insulating film in a high-speed and highly reliable semiconductor device. is there.
[0011]
A semiconductor device of the present invention has the low dielectric constant insulating film of the present invention as an interlayer insulating film. This is effective for a semiconductor integrated circuit that requires a high response speed. That is, in the multilayer wiring of the semiconductor integrated circuit, the reduction of the signal propagation speed is determined by the wiring resistance and the parasitic capacitance between the wirings. Due to high integration of devices, wiring widths and wiring intervals are becoming narrower, wiring resistance is increasing, and parasitic capacitance between wirings is increasing. The capacitance of the insulating film can be reduced by reducing the wiring thickness and the cross-sectional area, but if the wiring thickness is reduced, the wiring resistance is further increased, which does not lead to an increase in speed. In order to increase the speed, it is necessary to reduce the resistance of the wiring and the dielectric constant of the insulating film, which are major factors that govern the performance of the device. Since the semiconductor device of the present invention has the low dielectric constant insulating film of the present invention, which has a low dielectric constant and excellent heat resistance, moisture resistance, and mechanical strength, as an interlayer insulating film, a high-speed and highly reliable flash It can be used as a memory, DRAM, FRAM, MOS transistor, and the like.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
(Low dielectric constant insulating film forming method)
The method for producing a low dielectric constant insulating film of the present invention includes a siloxane resin film forming step, a surface treatment step, and a baking step, and further includes other steps as necessary.
[0013]
<Siloxane resin film forming step>
In the siloxane resin film forming step, a low dielectric constant insulating film forming material containing a siloxane resin is applied on a substrate to form a siloxane resin film.
The material for forming a low dielectric constant insulating film contains a siloxane resin and, if necessary, other components.
[0014]
-Siloxane resin-
The siloxane resin has at least a siloxane bond in one molecule, and preferably has a thermally decomposable group in a side chain.
Preferably, the thermally decomposable group is a group that thermally decomposes at 150 to 350 ° C. If the temperature of the thermal decomposition of the heat-decomposable group is lower than 150 ° C., a porous low-dielectric-constant insulating film cannot be formed. In this case, since the film is too hardened, pores are hardly formed, and the polymer skeleton of the siloxane resin is denatured or gelled by high heat.
[0015]
In the present invention, the thermal decomposition temperature can be measured by a usual thermogravimetric analysis method using a known thermogravimetric analyzer. At this time, if the thermogravimetric analyzer is equipped with a mass spectrometer, it is advantageous in that the cracked gas generated by the thermal decomposition can be analyzed.
[0016]
The thermally decomposable group is not particularly limited as long as it is a group that thermally decomposes at 150 to 350 ° C. However, in view of excellent thermal decomposability in this temperature range, it contains at least one of an ester bond and an ether bond. Is preferred.
[0017]
As the siloxane resin, at least one of the following general formulas (1) and (2) is preferable.
[0018]
Embedded image
General formula (1)

[0019]
In the general formula (1), R ¹ ~ R ³ Represents a hydrogen atom, a fluorine atom, -O-, or a substituent which may be the same or different. m represents an integer of 5 to 200, preferably an integer of 10 to 100.
[0020]
Embedded image
General formula (2)

[0021]
In the general formula (2), R ⁴ ~ R ⁷ At least one of them is a hydrogen atom, and the others represent a hydrogen atom, a fluorine atom, or a substituent which may be the same or different. n represents an integer of 5 to 200, preferably an integer of 10 to 100.
[0022]
In the general formulas (1) and (2), the substituent represents an alkyl group, a group having an ether bond or an ester bond. As the alkyl group, those having 1 to 10 carbon atoms are preferable. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, n-hexyl group, isohexyl Group, n-heptyl group, n-octyl group, isooctyl group, n-decyl group, isodecyl group and the like.
The group having an ether bond or an ester bond preferably has 1 to 10 carbon atoms, particularly preferably 1 to 5 carbon atoms. In the group having an ether bond (COC), the ether bond may have one or two or more. In the group having an ester bond (COO), the ester bond may have one or two or more.
[0023]
As the siloxane resin, specifically, a siloxane resin produced by a sol-gel method using a silane compound (for example, a sol-gel polymer of tetraalkoxysilane, a sol-gel polymer of trialkoxysilane, a sol-gel polymer of methyltrialkoxysilane, tetraalkoxysilane, Sol-gel polymer of trialkoxysilane, sol-gel polymer of tetraalkoxysilane and methyltrialkoxysilane, sol-gel polymer of methyltrialkoxysilane and trialkoxysilane, sol-gel polymer of tetraalkoxysilane and dimethylalkoxysilane, etc.), methylsilsesquioxane resin , Hydrogen silsesquioxane resin, fluorine silsesquioxane resin, fluorine-containing hydrogen silsesquioxane resin, fluorine-containing methyl silsesquioxane Hexane resins.
[0024]
Examples of the silane compound include tetraalkoxysilane, trialkoxysilane, methyltrialkoxysilane, ethyltrialkoxysilane, propyltrialkoxysilane, phenyltrialkoxysilane, vinyltrialkoxysilane, allyltrialkoxysilane, glycidyltrialkoxy Silane, dialkoxy silane, dimethyl dialkoxy silane, diethyl dialkoxy silane, dipropyl dialkoxy silane, diphenyl dialkoxy silane, divinyl dialkoxy silane, diallyl dialkoxy silane, diglycidyl dialkoxy silane, phenyl methyl dialkoxy silane, Phenylethyl dialkoxysilane, phenylpropyl trialkoxysilane, phenylvinyl dialkoxysilane, phenylallyl Alkoxysilane, phenylglycidyl dialkoxysilane, methyl vinyl dialkoxy silane, ethyl vinyl dialkoxy silane, propyl vinyl dialkoxy silane, and the like, and these may be used alone or in combination of two or more You may use together.
[0025]
-Other components-
Examples of the other components include a diluting solvent in which the siloxane resin can be dissolved, a thermally decomposable resin, and the like.
The diluting solvent is not particularly limited as long as the siloxane resin and polycarbosilane are dissolved, and examples thereof include cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, octane, decane, propylene glycol, propylene glycol monomethyl ether, and propylene glycol. Monomethyl ether acetate, etc., may be used, and these may be used alone or in combination of two or more.
[0026]
As the thermally decomposable resin, those having a thermal decomposition temperature of 150 to 350 ° C. are preferable. For example, polyolefins, acrylic polymers, styrene-acryl copolymers, chlorinated polyethylene, polypropylene, ionomers, and other olefin-based polymers are preferred. Coalescence, polyvinyl chloride, polyester, polyamide, polyurethane, epoxy resin, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl acetal resin such as polyvinyl butyral resin, phenol resin, rosin modified phenol resin, xylene resin, rosin modified maleic resin And various polymers such as rosin ester and petroleum resin.
[0027]
The weight average molecular weight (Mw) of the siloxane resin is preferably from 500 to 50,000,000, more preferably from 7,000 to 48,000,000.
If the weight average molecular weight (Mw) is less than 500, the boiling point is low, and it may be decomposed and eliminated together with the thermally decomposable group during heat treatment. May have poor solubility.
[0028]
The content of the siloxane resin in the low dielectric constant insulating film forming material is preferably from 20 to 80% by mass, and more preferably from 30 to 70% by mass.
[0029]
The method for producing the low dielectric constant insulating film forming material is not particularly limited and can be appropriately selected depending on the purpose.For example, after dissolving the silane compound or the like in the diluting solvent, the silane compound is dissolved. A method of adding a polymerization catalyst to be polymerized, and the like can be given.
[0030]
As the polymerization catalyst, for example, a compound containing at least one of aliphatic, alicyclic and aromatic hydrocarbons in one molecule is preferable. Specifically, maleic acid, acetic acid, sulfonic acid And organic acid compounds such as toluenesulfonic acid, and organic alkali compounds such as pyridine and triethylamine. These may be used alone or in combination of two or more.
It is preferable to use the organic acid compound or the organic alkali compound as the polymerizing catalyst since the generation of structural defects of silica molecules is further suppressed when forming the low dielectric constant insulating film. In addition, by using the organic alkali compound as the polymerizing catalyst, high-density silica is formed when the low dielectric constant insulating film is formed, so that a decrease in film strength is effectively suppressed.
[0031]
-Coating method-
The coating method is not particularly limited, and includes a known coating method, for example, a spin coating method, a dip coating method, a kneader coating method, a curtain coating method, a blade coating method, a scan coating method, and the like. Among these, a spin coating method, a dip coating method, and the like are preferable in terms of coating efficiency and the like.
After the application, a solvent or the like can be dried as necessary. The temperature for the drying is not particularly limited and can be appropriately selected depending on the purpose. However, about 100 to 250 ° C. is preferable. As described later, when the siloxane resin film is insolubilized by heat treatment, it can be performed simultaneously with the drying heat treatment.
[0032]
<Surface treatment process>
In the surface treatment step, the surface of the siloxane resin film is made hydrophilic with a surface treatment solution selected from an organic solvent having a hydroxyl group and an aqueous solution having a pH of 1 to 10.
[0033]
-An organic solvent having a hydroxyl group-
The organic solvent having a hydroxyl group is not particularly limited, but is preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, tert-butyl alcohol having one or more hydroxyl groups in one molecule. And phenols such as phenol, cresol, diethylphenol, triethylphenol, propylphenol, nonylphenol, vinylphenol, allylphenol and nonylphenol. In addition, water may be added to the organic solvent having a hydroxyl group.
[0034]
-Aqueous solution of pH 1 to 10-
The aqueous solution having a pH of 1 to 10 is not particularly limited, and examples thereof include acidic aqueous solutions such as a hydrochloric acid aqueous solution, a nitric acid aqueous solution, and a sulfuric acid aqueous solution; An aqueous alkaline solution such as an aqueous solution; an organic alkaline aqueous solution such as dimethylamine, propylamine, hexamethylamine, cyclohexylamine, dicyclohexylamine, and tetramethylammonium hydroxide; When the surface treatment is performed with an aqueous solution having a pH of more than 10, the siloxane resin may be decomposed, which is not preferable.
[0035]
The method of performing the surface treatment with the surface treatment liquid is not particularly limited, and examples thereof include a method of spin-coating a siloxane resin film and then dropping the film onto the film from a nozzle of a pipette or a spin coater.
[0036]
When performing the surface treatment on the siloxane resin film, if the siloxane resin film is dissolved in the surface treatment liquid, it is preferable to perform an insolubilization treatment for insolubilizing the siloxane resin film in the surface treatment liquid before the surface treatment step. preferable.
Examples of the insolubilization treatment include heat treatment, light irradiation, and electron beam irradiation, and among these, heat treatment is preferable because it is simple and low cost.
When heat treatment is performed as the insolubilization treatment, the heat treatment may be performed in an atmosphere containing 1% or more of oxygen and at 100 to 400 ° C, preferably 100 to 300 ° C. This is because if the temperature is lower than 100 ° C., it is difficult to insolubilize, while if the temperature exceeds 400 ° C., the low dielectric constant insulating film is damaged by oxidation.
It is preferable that the drying of the siloxane resin film and the insolubilization of the siloxane resin film in the step of forming the siloxane resin film are simultaneously performed by heat treatment from the viewpoint of increasing the production efficiency.
[0037]
<Firing step>
In the baking step, the siloxane resin film subjected to the surface treatment is baked.
The firing is preferably performed at 200 to 500 ° C. in an atmosphere selected from an inert atmosphere, a vacuum atmosphere, and an atmosphere containing 10 ppm or more of oxygen. In particular, when the heat treatment is performed at 500 ° C. or more in an atmosphere containing 10 ppm or more of oxygen, the low dielectric constant insulating film is oxidized, and the dielectric constant can be increased.
[0038]
(Low dielectric constant insulating film)
The low dielectric constant insulating film is manufactured by the method for manufacturing a low dielectric constant insulating film of the present invention.
The low dielectric constant insulating film has a dielectric constant of 3.0 or less, preferably 2.8 or less. Here, the dielectric constant can be measured with a dielectric constant measuring device by forming a gold electrode on a low dielectric constant insulating film.
The low dielectric constant insulating film has an elastic modulus of 5.5 GPa or more, preferably 7.0 GPa or more, and more preferably 8.0 GPa or more.
Here, the elastic modulus can be measured using a nano indenter.
The diameter (average diameter) of the holes (voids) formed in the low dielectric constant insulating film is not particularly limited and can be appropriately selected depending on the intended purpose. Or less, more preferably 8 nm or less.
The diameter (average diameter) of the holes can be measured by observing with a transmission microscope (TEM).
The thickness of the low-dielectric-constant insulating film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 50 to 3000 nm.
[0039]
In the present invention, since a high-density silica can be formed particularly when a porous film containing a pyrolytic resin or a pyrolytic functional group is formed on a siloxane resin, it has a low dielectric constant, a low moisture resistance, and a high mechanical strength. A dielectric constant insulating film can be formed. Therefore, the film formed according to the present invention is effective as a low dielectric constant interlayer insulating film of a semiconductor device, and a semiconductor integrated circuit having a high device response speed can be obtained by using this insulating film.
[0040]
(Semiconductor device)
The semiconductor device of the present invention is not particularly limited except that it has the low dielectric constant insulating film of the present invention as an interlayer insulating film, and includes members appropriately selected according to the purpose. Preferable examples of the semiconductor device of the present invention include a flash memory, a DRAM, an FRAM, and a MOS transistor.
Since the semiconductor device of the present invention has the low-dielectric-constant insulating film of the present invention as an interlayer insulating film, the semiconductor device of the present invention has excellent insulating properties between the layers, high speed, and high reliability.
[0041]
Hereinafter, an example of the semiconductor device of the present invention will be described with reference to FIG. The semiconductor device of the present invention is obtained, for example, as follows. That is, as shown in FIG. 1, first, a transistor layer in which a gate electrode 4 having a source diffusion layer 5a, a drain diffusion layer 5b, and a side wall insulating film 3 is formed is formed by being separated by an element isolation film 2. An interlayer insulating film (phosphorus glass) 6 and a stopper film 7 are formed on the silicon wafer 1 thus formed, and a contact hole for taking out an electrode is formed. After a barrier film 8 (TiN; 50 nm) is formed in this contact hole by sputtering, WF ₆ Then, the conductive plug (W) 9 is buried by mixing and reducing hydrogen, and a portion other than the via is removed by chemical mechanical polishing (CMP).
[0042]
Subsequently, after a low dielectric constant insulating film 10 (thickness: 450 nm) is formed on the stopper film 7 by the method for manufacturing a low dielectric constant insulating film of the present invention, TEOS-SiO ₂ (Cap film 12) is laminated to a thickness of 50 nm. The cap film 12 is formed by using the resist layer on which the first wiring pattern is ₄ / CHF ₃ Processing is performed by F plasma using gas as a raw material.
[0043]
In this wiring groove, a barrier film 8 (TiN) (50 nm) serving as a diffusion barrier of Cu to the insulating layer and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating are formed by sputtering. Further, after laminating copper (600 nm) by electrolytic plating, a metal other than the wiring pattern portion is removed by chemical mechanical polishing (CMP) to form a copper wiring layer.
[0044]
Next, a dual damascene method for simultaneously forming a via layer and a wiring layer will be described. On the first wiring layer, a SiN film (50 nm) is formed as a diffusion prevention film 13 by plasma CVD using silane and ammonia gas for the purpose of preventing Cu diffusion. A low dielectric constant insulating film 10 (50 nm) is laminated by a manufacturing method. An SiN film (50 nm) is formed as a stopper film 7 by plasma CVD using silane and ammonia gas on the wiring layer portion, and further, a low dielectric constant insulating film 10 is formed by the method of manufacturing a low dielectric constant insulating film of the present invention. (400 nm). TEOS-SiO as the cap film 12 (50 nm) ₂ Stack the films. A CF is formed on the low dielectric constant insulating film 10 using the resist layer on which the via pattern is formed as a mask. ₄ / CHF ₃ By changing gas composition by F plasma using gas as raw material, SiO ₂ / Low dielectric constant insulating film / SiN / Low dielectric constant insulating film / SiN are processed in this order. Subsequently, using the resist layer provided with the second-layer wiring pattern as a mask, CF ₄ / CHF ₃ Processing is performed by F plasma using gas as a raw material. A barrier film 8 (TiN; 50 nm) serving as a diffusion barrier for Cu to the insulating layer and a seed layer Cu (50 nm) serving as an electrode during electrolytic plating are formed in the vias and the wiring grooves by sputtering. Further, after laminating copper (1400 nm) by electrolytic plating, the metal other than the wiring pattern portion is removed by CMP, and the portion other than the via is removed by chemical mechanical polishing (CMP) in which the copper wiring 14 is formed. To form As a result, the above steps can be repeated to form a three-layer wiring. In this way, in the obtained multilayer wiring, the yield of one million continuous vias can be 90% or more.
[0045]
【Example】
Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.
[0046]
(Production Example 1)
-Production of low dielectric constant insulating film forming material-
20.8 g (0.1 mol) of tetraethoxysilane, 17.8 g (0.1 mol) of methyltriethoxysilane, 23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane, and 39.6 g of methyl isobutyl ketone Into a 200 ml reaction vessel, 16.2 g (0.9 mol) of a 1% by mass aqueous solution of tetramethylammonium hydroxide was added dropwise over 10 minutes, and a ripening reaction was performed for 2 hours after completion of the addition.
Next, 5 g of magnesium sulfate was added to remove excess water, and then ethanol produced by the aging reaction was removed by a rotary evaporator until the reaction solution became 50 ml. 20 ml of methyl isobutyl ketone was added to the obtained reaction solution, and methyl isobutyl ketone was removed in an oven at 200 ° C.
The solid content concentration of the obtained low dielectric constant insulating film forming material of Production Example 1 was 18.2% by mass (weight average molecular weight of siloxane resin; 172,000).
[0047]
(Production Example 2)
-Production of low dielectric constant insulating film forming material-
200 ml of 20.8 g (0.1 mol) of tetraethoxysilane, 16.1 g (0.1 mol) of triethoxysilane, 23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane, and 39.6 g of methyl isobutyl ketone , And 16.2% (0.9 mol) of a 1% by mass aqueous solution of tetramethylammonium hydroxide was added dropwise over 10 minutes. After the completion of the dropwise addition, an aging reaction was performed for 2 hours.
Next, 5 g of magnesium sulfate was added to remove excess water, and then ethanol produced by the aging reaction was removed by a rotary evaporator until the reaction solution became 50 ml. 20 ml of methyl isobutyl ketone was added to the obtained reaction solution, and methyl isobutyl ketone was removed in an oven at 200 ° C.
The solid content concentration of the obtained low dielectric constant insulating film forming material of Production Example 2 was 15.4% by mass (weight average molecular weight of siloxane resin; 260,000).
[0048]
(Production Example 3)
-Production of low dielectric constant insulating film forming material-
88 g (0.9 mol) of sulfuric acid and fuming sulfuric acid (60% SO) were placed in a reaction vessel equipped with a nitrogen gas inlet tube and a liquid metering pump. ₄ ) Was charged, and 87 g (0.95 mol) of toluene was added dropwise at a rate of 2 ml / min using a metering pump, and an aging reaction was performed for 1 hour after the addition was completed.
Next, a raw material solution obtained by diluting 41 g (0.3 mol) of trichlorosilane to 20% by mass in toluene was dropped at a rate of 2 ml / min using a metering pump, and after the dropping was completed, an aging reaction was performed for 2 hours. After the completion of the reaction, 100 ml of a 50% by mass aqueous solution of sulfuric acid was added, and the precipitated toluenesulfonic acid was filtered. Then, excess sulfuric acid aqueous solution was removed with a separating funnel.
The sulfuric acid remaining in the solution was neutralized with 2 g of calcium carbonate, dehydrated with 5 g of magnesium sulfate, and toluene was completely removed using a rotary evaporator to obtain 15 g of a hydrogen silsesquioxane resin solid ( Weight average molecular weight; 4800).
The obtained hydrogen silsesquioxane resin was dissolved in 70 g of methyl isobutyl ketone to prepare a solution having a solid content of 17.5% (low dielectric constant insulating film forming material of Production Example 3).
[0049]
(Production Example 4)
-Production of low dielectric constant insulating film forming material-
88 g (0.9 mol) of sulfuric acid and fuming sulfuric acid (60% SO) were placed in a reaction vessel equipped with a nitrogen gas inlet tube and a liquid metering pump. ₄ ) Was charged, and 87 g (0.95 mol) of toluene was added dropwise at a rate of 2 ml / min using a metering pump, and an aging reaction was performed for 1 hour after the addition was completed.
Next, a raw material solution obtained by diluting 36 g (0.27 mol) of trichlorosilane and 4.6 g of fluorotrichlorosilane in toluene to 20% by mass was dropped at a rate of 2 ml / min using a metering pump. Was done. After the completion of the reaction, 100 ml of a 50% by mass aqueous solution of sulfuric acid was added, and the precipitated toluenesulfonic acid was filtered. Then, excess sulfuric acid aqueous solution was removed with a separating funnel.
The sulfuric acid remaining in the solution was neutralized with 2 g of calcium carbonate, dehydrated with 5 g of magnesium sulfate, and toluene was completely removed using a rotary evaporator to obtain 15 g of a hydrogen silsesquioxane resin solid ( Weight average molecular weight; 3900).
The obtained hydrogen silsesquioxane resin was dissolved in 70 g of methyl isobutyl ketone to prepare a solution having a solid content of 17.5% (the material for forming a low dielectric constant insulating film of Production Example 4).
[0050]
(Example 1)
-Formation of low dielectric constant insulating film-
The material for forming a low dielectric constant insulating film produced in Production Example 1 was spin-coated on a Si wafer at 3000 rpm for 20 seconds, and then dried at 200 ° C. in the air.
Next, a surface treatment was performed with isopropyl alcohol. Thereafter, annealing was performed in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less at 400 ° C. for 30 minutes to form the low dielectric constant insulating film of Example 1.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 1.97. The elastic modulus measured by a nano indenter was 7.2 GPa. Table 1 shows the results. Furthermore, when the average pore diameter was measured by a transmission microscope (TEM), it was 6.3 nm.
[0051]
(Example 2)
-Formation of low dielectric constant insulating film-
The low dielectric constant insulating film of Example 2 was formed in the same manner as in Example 1 except that an aqueous ammonia solution of pH 8 was used as the solution for performing the surface treatment.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured to be 2.01. The elastic modulus was measured with a nano indenter to be 7.8 GPa. Table 1 shows the results. Furthermore, when the average pore diameter was measured by a transmission microscope (TEM), it was 7.2 nm.
[0052]
(Comparative Example 1)
-Formation of low dielectric constant insulating film-
In Example 1, the low dielectric constant insulating film of Comparative Example 1 was formed by the same method except that the surface treatment was not performed.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 1.98. The elastic modulus measured by a nano indenter was 4.4 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured with a transmission microscope (TEM), it was 8.9 nm.
[0053]
(Example 3)
-Formation of low dielectric constant insulating film-
The material for forming a low dielectric constant insulating film formed in Production Example 2 was spin-coated on a Si wafer at 3000 rpm for 20 seconds, and then dried at 200 ° C. in the air.
Next, a surface treatment was performed with isopropyl alcohol. Thereafter, annealing was performed at 400 ° C. for 30 minutes in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less to form a low dielectric constant insulating film of Example 3.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 1.95. The elastic modulus was measured by a nano indenter to find that it was 8.0 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured with a transmission microscope (TEM), it was 7.8 nm.
[0054]
(Example 4)
-Formation of low dielectric constant insulating film-
The low dielectric constant insulating film of Example 4 was formed in the same manner as in Example 3 except that an aqueous ammonia solution of pH 8 was used as the solution for performing the surface treatment.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 1.98. In addition, the modulus of elasticity was measured with a nano indenter, and it was 8.2 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured with a transmission microscope (TEM), it was 7.6 nm.
[0055]
(Comparative Example 2)
-Formation of low dielectric constant insulating film-
A low dielectric constant insulating film of Comparative Example 2 was formed in the same manner as in Example 3 except that the surface treatment was not performed.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 1.99. Moreover, the elastic modulus was measured with a nano indenter, and was 4.9 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured by a transmission microscope (TEM), it was 8.2 nm.
[0056]
(Example 5)
-Formation of low dielectric constant insulating film-
The material for forming a low dielectric constant insulating film produced in Production Example 3 was spin-coated on a Si wafer at 3000 rpm for 20 seconds, and then dried at 200 ° C. in the air.
Next, a surface treatment was performed with isopropyl alcohol. Thereafter, annealing was performed at 400 ° C. for 30 minutes in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less to form a low dielectric constant insulating film of Example 5.
A gold electrode of 1 mmφ was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.72. The elastic modulus was measured with a nano indenter to be 8.6 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured by a transmission microscope (TEM), it was 7.4 nm.
[0057]
(Example 6)
-Formation of low dielectric constant insulating film-
The low dielectric constant insulating film of Example 6 was formed in the same manner as in Example 5 except that an aqueous ammonia solution of pH 8 was used as the solution for performing the surface treatment.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.66. The elastic modulus was measured with a nano indenter and found to be 10 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured by a transmission microscope (TEM), it was 7.5 nm.
[0058]
(Comparative Example 3)
-Formation of low dielectric constant insulating film-
A low dielectric constant insulating film of Comparative Example 3 was formed in the same manner as in Example 5 except that the surface treatment was not performed.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.85. The elastic modulus was measured with a nano indenter and found to be 5.4 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured with a transmission microscope (TEM), it was 7.6 nm.
[0059]
(Example 7)
-Formation of low dielectric constant insulating film-
The material for forming a low dielectric constant insulating film formed in Production Example 4 was spin-coated on a Si wafer at 3000 rpm for 20 seconds, and then dried at 200 ° C. in the air.
Next, a surface treatment was performed with isopropyl alcohol. Thereafter, annealing was performed at 400 ° C. for 30 minutes in a nitrogen atmosphere having an oxygen concentration of 100 ppm or less, thereby forming a low dielectric constant insulating film of Example 7.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.46. The elastic modulus was measured with a nano indenter to be 7.8 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured by a transmission microscope (TEM), it was 7.4 nm.
[0060]
(Example 8)
-Formation of low dielectric constant insulating film-
The low dielectric constant insulating film of Example 8 was formed in the same manner as in Example 7 except that an aqueous ammonia solution having a pH of 8 was used as the solution for performing the surface treatment.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.45. Moreover, the elastic modulus was measured with a nano indenter, and it was 9.5 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured with a transmission microscope (TEM), it was 8.6 nm.
[0061]
(Comparative Example 4)
-Formation of low dielectric constant insulating film-
A low dielectric constant insulating film of Comparative Example 4 was formed in the same manner as in Example 7 except that the surface treatment was not performed.
A gold electrode having a diameter of 1 mm was formed on the obtained low dielectric constant insulating film, and the dielectric constant was measured. As a result, the dielectric constant was 2.49. The elastic modulus measured by a nano indenter was 5.1 GPa. Table 1 shows the results. Furthermore, when the average pore size was measured by a transmission microscope (TEM), it was 8.3 nm.
[0062]
[Table 1]

[0063]
(Example 9)
-Fabrication of semiconductor device-
The semiconductor device of the present invention including the low dielectric constant insulating film of the present invention manufactured by the method for manufacturing a low dielectric constant insulating film of the present invention was obtained as follows.
That is, as shown in FIG. 1, first, a Si layer separated by an element isolation film 2 and formed with a transistor layer having a gate electrode having a source diffusion layer 5 a, a drain diffusion layer 5 b, and a sidewall insulating film 3 is formed. An interlayer insulating film 6 and a stopper film 7 were formed on the wafer 1, and a contact hole for taking out an electrode was formed. After forming 50 nm of TiN 8 in this contact hole by sputtering, WF ₆ Then, the conductive plug (W) 9 was buried by mixing and reducing hydrogen, and a portion other than the via was removed by chemical mechanical polishing (CMP).
[0064]
Subsequently, a low-dielectric-constant insulating film 10 according to the present invention is formed on a Si flat plate under the condition of 450 nm in the same manner as in Example 1, and then TEOS-SiO 2 is formed as a cap film. ₂ 12 were stacked in a thickness of 50 nm. Using the resist layer in which the first wiring pattern is formed on the cap film 12 as a mask, CF ₄ / CHF ₃ It was processed by F plasma using gas as a raw material.
[0065]
In this wiring groove, 50 nm of TiN 8 acting as a diffusion barrier for Cu to the insulating layer and a seed layer Cu (50 nm) acting as an electrode during electrolytic plating were formed by sputtering. Furthermore, after laminating Cu14 by 600 nm by electrolytic plating, the metal other than the wiring pattern portion was removed by chemical mechanical polishing (CMP) to form a wiring layer.
[0066]
Next, a dual damascene method for simultaneously forming a via layer and a wiring layer will be described. On the first wiring layer, a low dielectric constant insulating film 10 is formed by a plasma CVD method using a silane and an ammonia gas as a diffusion preventing film with a thickness of 50 nm as a diffusion preventing film in the same manner as in Example 1 for the purpose of preventing Cu diffusion. 650 nm is laminated. In the wiring layer portion, a low dielectric constant insulating film 10 is formed as a stopper film by plasma CVD using silane and ammonia gas on the Si flat plate at a thickness of 40 nm in the same manner as in Example 1 under the condition of 40 nm. After that, TEOS-SiO is used as a cap film. ₂ (12) was laminated in a thickness of 50 nm. Using a resist layer in which a via pattern is formed on the insulating layer as a mask, CF ₄ / CHF ₃ SiO2 by changing gas composition by F plasma using gas as raw material ₂ / Low dielectric constant insulating film / SiN / Low dielectric constant insulating film / SiN were processed in this order. Subsequently, the resist layer provided with the second-layer wiring pattern is ₄ / CHF ₃ It was processed by F plasma using gas as a raw material. In this via and wiring groove, 50 nm of TiN8 acting as a diffusion barrier of Cu to the insulating layer and 50 nm of a seed layer Cu acting as an electrode during electrolytic plating were formed by sputtering. Furthermore, after laminating Cu 1400 nm by electrolytic plating, the metal other than the wiring pattern portion is removed by CMP, and the portion other than the via is removed by chemical mechanical polishing (CMP) in which the wiring layer is formed to form a via layer. did. Thereafter, the above steps were repeated to form a three-layer wiring.
As described above, in the multilayer wiring in the obtained semiconductor device, the yield of one million continuous vias could be made 90% or more.
[0067]
Here, the preferred embodiments of the present invention are as follows.
(Supplementary Note 1) A siloxane resin film forming step of forming a siloxane resin film by applying a low dielectric constant insulating film forming material containing a siloxane resin on a substrate, and making the surface of the siloxane resin film hydrophilic with a surface treatment liquid A method of producing a low dielectric constant insulating film, comprising: a surface treatment step of performing the following; and a baking step of baking the surface-treated siloxane resin film.
(Supplementary Note 2) The method of Supplementary Note 1, wherein the low dielectric constant insulating film forming material includes a siloxane resin having a thermally decomposable group in a side chain that is thermally decomposed at 150 to 350 ° C.
(Supplementary note 3) The method for producing a low dielectric constant insulating film according to supplementary note 2, wherein the thermally decomposable group contains at least one of an ester bond and an ether bond.
(Supplementary Note 4) The method for producing a low dielectric constant insulating film according to any one of Supplementary notes 1 to 3, wherein the low dielectric constant insulating film forming material contains a thermally decomposable resin.
(Supplementary Note 5) The method for producing a low dielectric constant insulating film according to any one of Supplementary notes 1 to 4, wherein the siloxane resin is represented by at least one of the following general formulas (1) and (2).
Embedded image
General formula (1)

In the general formula (1), R ¹ ~ R ³ Represents a hydrogen atom, a fluorine atom, -O-, or a substituent which may be the same or different. m represents an integer of 5 to 200.
Embedded image
General formula (2)

In the general formula (2), R ⁴ ~ R ⁷ At least one of them is a hydrogen atom, and the others represent a hydrogen atom, a fluorine atom, or a substituent which may be the same or different. n represents an integer of 5 to 200.
(Supplementary Note 6) The method for producing a low dielectric constant insulating film according to Supplementary Note 5, wherein the substituent in the general formula (1) is an alkyl group or a group having an ether bond or an ester bond.
(Supplementary Note 7) The method for producing a low dielectric constant insulating film according to any one of Supplementary notes 1 to 6, wherein the low dielectric constant insulating film forming material is applied to the substrate by spin coating in the siloxane resin film forming step.
(Supplementary Note 8) The method for producing a low dielectric constant insulating film according to any one of Supplementary Notes 1 to 7, wherein the surface treatment liquid is selected from an organic solvent having a hydroxyl group and an aqueous solution having a pH of 1 to 10.
(Supplementary note 9) The method for producing a low dielectric constant insulating film according to supplementary note 8, wherein the organic solvent having a hydroxyl group is any one of an alcohol solvent and a phenol solvent having one or more hydroxyl groups in one molecule.
(Supplementary Note 10) The method for producing a low dielectric constant insulating film according to Supplementary Note 8, wherein the aqueous solution having a pH of 1 to 10 is any one of an aqueous solution of an inorganic acid, an aqueous solution of an organic acid, an aqueous solution of an alkali, and an aqueous solution of an organic alkali.
(Supplementary Note 11) The method for producing a low dielectric constant insulating film according to any one of Supplementary Notes 1 to 10, wherein an insolubilization treatment for insolubilizing the siloxane resin film with respect to the surface treatment liquid is performed before the surface treatment step.
(Supplementary note 12) The method for producing a low dielectric constant insulating film according to supplementary note 11, wherein the insolubilization treatment is any of heat treatment, light irradiation, and electron beam irradiation.
(Supplementary Note 13) The method for producing a low dielectric constant insulating film according to any one of Supplementary Notes 1 to 12, wherein a heat treatment is performed on the siloxane resin film to insolubilize the surface treatment solution before the surface treatment step.
(Supplementary Note 14) The method for producing a low dielectric constant insulating film according to any one of Supplementary notes 13 to 14, wherein the formation of the siloxane resin film and the insolubilization treatment in the siloxane resin film formation step are simultaneously performed by heat treatment.
(Supplementary note 15) The method for producing a low dielectric constant insulating film according to any one of Supplementary notes 12 to 14, wherein the heat treatment is performed at 100 to 400 ° C in an atmosphere containing 1% or more of oxygen.
(Supplementary Note 16) The low dielectric constant insulating film according to any one of Supplementary Notes 1 to 15, wherein the firing is performed at 200 to 500 ° C in an atmosphere selected from an inert atmosphere, a vacuum atmosphere, and an atmosphere containing 10 ppm or more of oxygen. Production method.
(Supplementary Note 17) A low dielectric constant insulating film, which is manufactured by the method for manufacturing a low dielectric constant insulating film according to any one of Supplementary Notes 1 to 16.
(Supplementary Note 18) The low-dielectric-constant insulating film according to Supplementary Note 17, wherein the dielectric constant is 3.0 or less and the elastic modulus measured by a nanoindenter is 5.5 GPa or more.
(Supplementary note 19) The low-dielectric-constant insulating film according to Supplementary note 17 or 18, wherein the average diameter of the holes formed in the low-dielectric-constant insulating film is 10 nm or less.
(Supplementary Note 20) A semiconductor device comprising the low dielectric constant insulating film according to any one of Supplementary notes 17 to 19 as an interlayer insulating film.
[0068]
【The invention's effect】
According to the present invention, the above-mentioned conventional problems can be solved, a low dielectric constant insulating film having high mechanical strength, a method for manufacturing the same, and a high-speed and highly reliable semiconductor device using the low dielectric constant insulating film Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an example of a semiconductor device of the present invention using a low dielectric constant insulating film of the present invention.
[Explanation of symbols]
1 ... Silicon wafer
2 ・ ・ ・ Element separation film
3 ... sidewall insulating film
4 ... Gate electrode
5a Source diffusion layer
5b ·· Drain diffusion layer
6 ... Interlayer insulating film (phosphorus glass)
7 ... Stopper film
8 ... Barrier film
9 Conductor plug (W)
10. Low dielectric constant insulating film
12. Cap film
13..Diffusion prevention film
14. Copper wiring

Claims (10)

A siloxane resin film forming step of applying a low dielectric constant insulating film forming material containing a siloxane resin on a substrate to form a siloxane resin film, and a surface treatment step of making the surface of the siloxane resin film hydrophilic with a surface treatment liquid And a firing step of firing the surface-treated siloxane resin film. The method for producing a low dielectric constant insulating film according to claim 1, wherein the siloxane resin is represented by at least one of the following general formulas (1) and (2).
Embedded image
General formula (1)

In the formula (1), R ^{1 to} R ³ may be the same or different, and represent a hydrogen atom, a fluorine atom, —O—, or a substituent. m represents an integer of 5 to 200.
Embedded image
General formula (2)

In the general formula (2), at least one of R ^{4 to} R ⁷ is a hydrogen atom, and the others may be the same or different, and may be a hydrogen atom, a fluorine atom, or a substituted atom. Represents a group. n represents an integer of 5 to 200. The method for producing a low dielectric constant insulating film according to claim 1 or 2, wherein the surface treatment liquid is selected from an organic solvent having a hydroxyl group and an aqueous solution having a pH of 1 to 10. The method for producing a low dielectric constant insulating film according to any one of claims 1 to 3, wherein, before the surface treatment step, an insolubilization treatment for heat-treating the siloxane resin film to insolubilize the surface treatment liquid is performed. The method for producing a low dielectric constant insulating film according to claim 4, wherein the formation of the siloxane resin film and the insolubilization treatment in the siloxane resin film formation step are simultaneously performed by heat treatment. The method for manufacturing a low dielectric constant insulating film according to claim 4, wherein the heat treatment is performed at 100 to 400 ° C. in an atmosphere containing 1% or more of oxygen. The method for producing a low dielectric constant insulating film according to claim 1, wherein the firing is performed at 200 to 500 ° C. in an atmosphere selected from an inert atmosphere, a vacuum atmosphere, and an atmosphere containing 10 ppm or more of oxygen. . A low dielectric constant insulating film manufactured by the method for manufacturing a low dielectric constant insulating film according to claim 1. The low-dielectric-constant insulating film according to claim 8, wherein the dielectric constant is 3.0 or less, and the elastic modulus measured by a nanoindenter is 5.5 GPa or more. A semiconductor device comprising the low dielectric constant insulating film according to claim 8 or 9 as an interlayer insulating film.

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