JP2004023043A - Film forming method, film forming apparatus, and method of manufacturing semiconductor device - Google Patents

Abstract

An object of the present invention is to provide a film forming method capable of forming a high-quality compound film efficiently and easily when performing a film forming operation by batch processing using an ALD method.
Each wafer 23 is placed in a processing chamber 11 in which a Ta ₂ O ₂ film 28 is formed on the surfaces of a plurality of wafers 23 by batch processing using an ALD method. After arranging the surfaces so as to be separated from each other, the inside of the processing chamber 11 is purged by supplying Ar gas into the processing chamber 11, and the atmosphere in the processing chamber 11 is heated to reduce the indoor pressure to about 0.1 mm. The room temperature is maintained at about 280 ° C. at 6 Torr. While continuously supplying the Ar gas toward each wafer 23, the H ₂ O gas is supplied onto the surface of each wafer 23. After the supply of the H ₂ O gas is stopped, the Ar gas is continuously supplied to each wafer 23, and the PET gas is supplied on the surface of each wafer 23, so that Ta ₂ O is added on the surface of each wafer 23. _Two films 28 are formed.
[Selection] Figure 2

Description

【０１０３】
表１より、従来の熱ＣＶＤ法では、ＳＴＯ膜の膜厚の均一性を保持することはできても、穴４８のようなアスペクト比が大きい、細くて深い穴内での膜組成の均一性までは保持でき無いことが分かる。この表１によれば、穴４８の底では、殆どＴｉの酸化物膜しか成膜されないことを示す。すなわち、従来の熱ＣＶＤ法では、現在そして将来に向けたＬＳＩの微細化への追随が非常に困難であることが容易に予想される。
【０１０４】
また、図示しないキャパシタが有する平面形状のＲｕ電極上に、本実施形態に基づいて成膜したＳＴＯ膜４７、および従来の熱ＣＶＤ法に基づいて成膜したＳＴＯ膜の、それぞれの電気的特性を評価した結果を表２に示す。この表２によれば、従来の熱ＣＶＤ法に基づいて成膜したＳＴＯ膜に比べて、本実施形態に基づいて成膜したＳＴＯ膜４７の方が、より高い比誘電率およびより低いリーク電流値を示している。これは従来の熱ＣＶＤ法よりも、本実施形態のＡＬＤ成膜法の方が、より良好な結晶性を有する化合物膜を成膜するのにより適しているためと考えられる。
【０１０５】
【表２】

【０１０６】
また、本実施形態の成膜プロセスにおける成膜温度の最高値は約４００℃であるが、これは本プロセスを用いて形成したキャパシタを、例えば熱に弱い図示しないアルミニウム多層配線上に形成することが十分可能であることを示している。これにより、キャパシタ、ひいてはこのキャパシタを備える半導体装置を製造する際に、汚染管理が容易になることを意味する。また、例えば多層配線構造を有するＬＳＩ内の任意の層にキャパシタを混載しても、キャパシタよりも下層の配線、ひいてはＬＳＩ内の殆ど全ての層の配線間におけるコンタクトホールのアスペクト比増大等の問題を招かない等の利点を有することを意味する。
【０１０７】
以上説明したように、この第２実施形態においては、前述した第１実施形態と同様の効果を得ることができる。また、Ｓｒ原料としてシクロペンタジエニル系の化合物を用い、Ｔｉ原料としてアルコキシド、またはアルコキシドを含むＤＰＭ錯体を用いることで、Ｈ_２Ｏとの加水分解反応による配位子の一括除去が可能になり、低温での結晶化が容易になる。例えば、ＳＴＯ膜の場合、３００℃程度での結晶化が可能である。さらに、Ｓｒ原料ガスやＴｉ原料ガスは、約４００℃以下においてそれぞれ単独では酸素（Ｏ_２）や亜酸化窒素（Ｎ_２Ｏ）と殆ど反応しないので、パージガスとしてＯ_２やＮ_２Ｏの使用が可能である。これは、配位子等に起因するＳＴＯ膜中の有機不純物の効率的な除去できる点で有効である。
【０１０８】
なお、前述したように、これら本実施形態に基づいて成膜したＳＴＯ膜４７についての特性は、本実施形態に基づいて成膜するＢＳＴ膜についても略同様に当てはまる。
【０１０９】
（第３の実施の形態）
次に、本発明に係る第３実施形態を図８および図９を参照しつつ説明する。図８は、第３実施形態に係る成膜装置を簡略化して示す図である。図９は、第３実施形態に係る成膜方法のシーケンスを示す図である。なお、図１と同一部分は同一符号を付してその詳しい説明を省略する。
【０１１０】
本実施形態では、具体的には、Ａｔｏｍｉｃ　Ｌａｙｅｒ　Ｄｅｐｏｓｉｔｉｏｎ（ＡＬＤ）法をバッチ処理で実施することにより、化合物膜としてのＴｉ−Ａｌ−Ｎ膜を成膜する際の成膜方法および成膜装置、Ｔｉ−Ａｌ−Ｎ膜の成膜条件、そして得られたＴｉ−Ａｌ−Ｎ膜の特性について説明する。
【０１１１】
本実施形態の成膜プロセスでは、原料ガスとして、チタンクロライド（ＴｉＣｌ_４）、およびアルミニウムクロライド（ＡｌＣｌ_３）のそれぞれのガスを用いる。また、活性化ガスとしてＮＨ_３ガスを用いる。さらに、パージガスとしてアルゴン（Ａｒ）ガスを用いる。
【０１１２】
先ず、図８（ａ），（ｂ）を参照しつつ、本実施形態の成膜装置５１について説明する。
【０１１３】
図８（ａ）は、成膜装置５１の概略構成を正面もしくは側面から臨んで示す図である。図８（ｂ）は、成膜装置５１を図５（ａ）中実線矢印の向きから臨んで示す平面図である。この成膜装置５１は、前述した第１実施形態および第２実施形態と同様に、主に原料ガス供給系５２および反応系５３からなる。原料ガス供給系５２は、ＴｉＣｌ_４ガス供給系５４、ＡｌＣｌ_３ガス供給系５５、およびＮＨ_３ガス供給系５６などからなる。
【０１１４】
ＴｉＣｌ_４ガス供給系５４は、主にＴｉＣｌ_４ガスボンベ５６、このボンベ５６を加熱するＴｉＣｌ_４加熱装置５７、および高温仕様ＴｉＣｌ_４ガス流量制御装置５８などからなる。同様に、ＡｌＣｌ_３ガス供給系５５は、主にＡｌＣｌ_３ガスボンベ５９、このボンベ５９を加熱するＡｌＣｌ_３加熱装置６０、および高温仕様ＡｌＣｌ_３ガス流量制御装置６１などからなる。ＴｉＣｌ_４ガスボンベ５６およびＡｌＣｌ_３ガスボンベ５９の温度は、それぞれ約６０℃である。ＴｉＣｌ_４ガスよびＡｌＣｌ_３ガスは、それぞれ約８０℃に加熱されたＴｉＣｌ_４ガス配管６２およびＡｌＣｌ_３ガス配管６３を通り、原料ガス供給治具としての石英製のＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５に互いに独立に送られる。ＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５は互いに独立に反応容器１１内に設けられており、ＴｉＣｌ_４ガスよびＡｌＣｌ_３ガスはそれぞれＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５を経て反応容器１１内に供給される。
【０１１５】
ＴｉＣｌ_４ガス配管６２とＴｉＣｌ_４ガスインジェクター６４との接続部分付近、すなわちＴｉＣｌ_４ガスインジェクター６４の根元の部分には、ＴｉＣｌ_４ガスインジェクター６４に通すガスを、ＴｉＣｌ_４ガスまたはＡｒガスに選択的に切り替えることができるように、原料ガス供給系切り替えバルブ１２ｃが設けられている。同様に、ＡｌＣｌ_３ガス配管６３とＡｌＣｌ_３ガスインジェクター６５との接続部分付近、すなわちＡｌＣｌ_３ガスインジェクター６５の根元の部分には、ＡｌＣｌ_３ガスインジェクター６５に通すガスを、ＡｌＣｌ_３ガスまたはＡｒガスに選択的に切り替えることができるように、原料ガス供給系切り替えバルブ１２ｄが設けられている。
【０１１６】
Ｈ_２Ｏガス供給系５６は、主にＮＨ_３ガスボンベ６６およびＮＨ_３ガスのガス流量制御装置６７などからなる。ＮＨ_３ガスは約６０℃に加熱されたＮＨ_３ガス配管６８を通り、活性化ガス供給治具としての石英製のＮＨ_３ガスインジェクター６９に送られる。ＮＨ_３ガスインジェクター６９は、反応容器１１内に設けられており、ＮＨ_３ガスはＮＨ_３ガスインジェクター６９を経て反応容器１１内に供給される。ＮＨ_３ガス配管６８とＮＨ_３ガスインジェクター６９との接続部分付近、すなわちＮＨ_３ガスインジェクター６９の根元の部分には、ＮＨ_３ガスインジェクター６９に通すガスを、ＮＨ_３ガスまたはＡｒガスに選択的に切り替えることができるように、活性化ガス供給系切り替えバルブ１８ａが設けられている。
【０１１７】
このように、成膜装置３１は、３系統のガスインジェクター６４，６５，６９を備えている。また、ＴｉＣｌ_４ガスインジェクター６４、ＡｌＣｌ_３ガスインジェクター６５、およびＮＨ_３ガスインジェクター６９は、それぞれ第１実施形態および第２実施形態と同様に、多孔ガスインジェクターとして形成されている。
【０１１８】
他方、反応系５３は、第１実施形態および第２実施形態と同様に、成膜処理が施される被処理基板（ウェーハ）２３を複数枚同時に収容可能であるとともに、それら各ウェーハ２３を略均一に加熱できるように容器加熱装置２６が設けられたホットウォール式の反応容器１１、この反応容器１１内において各ウェーハ２３をそれらの表面を互いに所定の間隔離間させて支持可能な基板支持具としてのボート２４、反応容器１１内に供給された原料ガス、活性化ガス、およびパージガスを反応容器１１の外に排気する排気系２５などからなる。それとともに、反応容器（チャンバー）１１の内部をクリーニングするためのＣｌＦ_３ガスを反応容器１１内に供給する、ＣｌＦ_３ガス供給系７０を備えている。
【０１１９】
また、図８（ａ），（ｂ）に示すように、本実施形態の反応容器１１には、その内部に収容される各ウェーハ２３を間に挟んで、３本のガスインジェクター６４，６５，６９と対向する側（位置）に、反応容器１１内の不要なガスを反応容器１１の外に排気するためのスリット状の排気孔７１が、各ウェーハ２３の枚数に応じて複数個設けられている。それとともに、ボート２４には、各排気孔７１付近から３本のガスインジェクター６４，６５，６９付近にかけて、各ウェーハ２３をそれらの両側方から囲む整流部材としての遮蔽板（整流板）７２が設けられている。これにより、３本のガスインジェクター６４，６５，６９を通して反応容器１１に供給された各ガスは、遮蔽板７２の外側に殆ど流れ出すこと無く、ボート２４に支持された各ウェーハ２３を集中的に包むように、各ガスインジェクター６４，６５，６９の吹き出し孔２７から各排気孔７１に向けて流れる。
【０１２０】
このような構造を採用することにより、第１に、反応容器１１の内壁自体に金属膜が堆積（付着）することを抑制して、各ウェーハ２３の温度を精密に制御することが可能になる。一般に、反応容器１１の内壁を覆う金属膜が多くなる程、例えば容器加熱装置２６などの外部熱源からの輻射熱が各ウェーハ２３に到達し難くなるためである。ところが、本実施形態の反応容器１１では、前述した構造により反応容器１１の内壁に金属膜が堆積することを抑制できるので、容器加熱装置２６により、反応容器１１内に収容された各ウェーハ２３の温度を精密に制御することができる。第２に、前述した構造により、原料ガス、活性化ガス、およびパージガスを、各ウェーハ２３の表面付近や、各ウェーハ２３同士の間など、各ウェーハ２３の周りに実質的にガスを閉じ込めつつ流すことができる。これにより、成膜反応の反応速度を高めることができるとともに、各ガスの利用効率をより向上させることができる。さらに、反応容器１１内、特に各ウェーハ２３の周りのパージを容易かつ迅速に行うことができるという利点も生まれる。
【０１２１】
さらに、際膜プロセスを複数回繰り返す場合には、各プロセス間に反応容器１１内にＣｌＦ_３ガスを供給することにより、反応容器１１内をＣｌＦ_３クリーニングすることができる。これにより、成膜処理を行うのに先立って、反応容器１１の内壁に堆積した金属膜を略完全に除去することが可能である。このように、本実施形態の成膜装置５１によれば、より適正な状態で化合物膜を成膜できる。
【０１２２】
次に、図９を参照しつつ、本実施形態の成膜方法について説明する。本実施形態の成膜方法は、具体的には、成膜装置５１を用いて、以下に述べるシーケンスで化合物膜としての図示しないＴｉ_０．７Ａｌ_０．３Ｎ膜を成膜するものである。
【０１２３】
成膜処理が施される複数枚のウェーハ２３には、Ｔｉ_０．７Ａｌ_０．３Ｎ膜が埋め込まれる開口径約１３０ｎｍの図示しないコンタクトホールが予め形成されている。そして、各ウェーハ２３の表面には、コンタクト抵抗を低減するために、予めロングスロースパッタ（ＬＴＳ）により図示しないＴｉ膜を約１０ｎｍ形成しておく。それとともに、各ウェーハ２３に対して、約６００℃のＲＴＡによりシリサイデーションを完了させておく。
【０１２４】
以上説明した処理が予め施された複数枚のウェーハ２３を反応容器１１内に導入し、反応容器１１内に配置されているボート２４に支持させる。続けて、容器加熱装置２６を用いて、反応容器１１内の雰囲気および各ウェーハ２３の温度が約５００℃になるように略均一に加熱する。それとともに、ＴｉＣｌ_４ガスインジェクター６４、ＡｌＣｌ_３ガスインジェクター６５、およびＮＨ_３ガスインジェクター６９からそれぞれ約１ＳＬＭずつＡｒガスを反応容器１１内に供給して、反応容器１１内の圧力を約１．０Ｔｏｒｒに保つ。反応容器１１内の温度（炉内温度）が５００℃±２０℃程度で安定していることを確認した後、容器内圧力を約１．０Ｔｏｒｒに保ちつつ、図６に示すシーケンスに基づいて以下に述べる成膜処理を実行する。
【０１２５】
先ず、反応容器１１内に、ＮＨ_３ガスインジェクター６９からＮＨ_３ガスを約１０秒間、約１ＳＬＭ導入するとともに、ＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５からはＡｒガスをそれぞれ約１０秒間、約５００ｓｃｃｍずつ供給する。反応容器１１内に導入されたＮＨ_３ガスは、各ウェーハ２３の表面に吸着する。
【０１２６】
次に、ＡｌＣｌ_３ガスインジェクター６５から反応容器１１内にＡｒガスを供給しつつ、ＮＨ_３ガスインジェクター６９から供給するガスをＡｒガスに切り替える。それとともに、ＴｉＣｌ_４ガスインジェクター６４から供給するガスをＴｉＣｌ_４ガスに切り替えて、反応容器１１内にＴｉＣｌ_４ガスを約５秒間、約１ＳＬＭ導入する。ＡｌＣｌ_３ガスインジェクター６５およびＮＨ_３ガスインジェクター６９から、Ａｒガスをそれぞれ約５秒間、約５００ｓｃｃｍずつ反応容器１１内に供給する。
【０１２７】
通常、５００℃前後ではＴｉＣｌ_４の分解反応は殆ど起こらないが、各ウェーハ２３の表面にはＮＨ_３が吸着しているので、各ウェーハ２３の表面に到達したＴｉＣｌ_４ガスは吸着しているＮＨ_３との間で分解反応を起こす。これにより、各ウェーハ２３の表面上に、図示しないＴｉの窒化物の膜が成膜される。
【０１２８】
次に、反応容器１１内に、再びＮＨ_３ガスインジェクター６９からＮＨ_３ガスを約１０秒間、約１ＳＬＭ導入するとともに、ＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５からはＡｒガスをそれぞれ約１０秒間、約１ＳＬＭずつ供給する。これにより、各ウェーハ２３の表面上に堆積されたＴｉが略完全に窒化されるとともに、このＴｉの窒化物の膜中に残留していたＴｉ原料中の塩素が塩化アンモニウムとなって離脱する。さらには、導入されたＮＨ_３ガスがＴｉ窒化物膜の表面に吸着する。
【０１２９】
以上説明したＮＨ_３ガスの供給およびＴｉＣｌ_４ガスの供給を交互に５回ずつ、約７５秒間かけて繰り返す。
【０１３０】
次に、ＮＨ_３ガスインジェクター６９からから供給するガスをＮＨ_３ガスに切り替えて、反応容器１１内にＮＨ_３ガスを約１０秒間、約１ＳＬＭ導入する。また、ＡｌＣｌ_３ガスインジェクター６５からＡｒガスを反応容器１１内に供給しつつ、ＴｉＣｌ_４ガスインジェクター６４から供給するガスをＡｒガスに切り替える。ＡｌＣｌ_３ガスインジェクター６５およびＴｉＣｌ_４ガスインジェクター６４からは、Ａｒガスをそれぞれ約１０秒間、約１ＳＬＭずつ反応容器１１内に供給する。
【０１３１】
次に、ＴｉＣｌ_４ガスインジェクター６４から反応容器１１内にＡｒガスを供給しつつ、ＡｌＣｌ_３ガスインジェクター６５から供給するガスをＡｌＣｌ_３ガスに切り替える。それとともに、ＮＨ_３ガスインジェクター６９から供給するガスをＡｒガスに切り替える。ＡｌＣｌ_３ガスインジェクター６５から、反応容器１１内にＡｌＣｌ_３ガスを約５秒間、約１ＳＬＭ供給する。また、ＴｉＣｌ_４ガスインジェクター６４およびＮＨ_３ガスインジェクター６９から、反応容器１１内にＡｒガスを約５秒間、それぞれ約１ＳＬＭずつ供給する。
【０１３２】
通常、５００℃前後では、ＡｌＣｌ_３の分解反応は殆ど起こらないが、各ウェーハ２３の表面に成膜されたＴｉ窒化物膜の表面にはＮＨ_３が吸着しているので、Ｔｉ窒化物膜の表面に到達したＡｌＣｌ_３ガスは吸着しているＮＨ_３との間で加水分解反応を起こす。これにより、各ウェーハ２３の表面上に、図示しないＡｌの窒化物の膜が成膜される。
【０１３３】
次に、反応容器１１内に、再びＮＨ_３ガスインジェクター６９からＮＨ_３ガスを約１０秒間、約１ＳＬＭ導入するとともに、ＴｉＣｌ_４ガスインジェクター６４およびＡｌＣｌ_３ガスインジェクター６５からはＡｒガスをそれぞれ約１０秒間、約１ＳＬＭずつ供給する。これにより、各ウェーハ２３の表面上に堆積されたＡｌが略完全に窒化されるとともに、このＡｌの窒化物の膜中に残留していたＡｌ原料中の塩素が塩化アンモニウムとなって離脱する。さらには、導入されたＮＨ_３ガスがＡｌ窒化物膜の表面に吸着する。
【０１３４】
以上説明したＮＨ_３ガスの供給およびＡｌＣｌ_３ガスの供給を交互に２回ずつ繰り返す。これにより、各ウェーハ２３の表面上に約３０秒で、Ｔｉ_０．７Ａｌ_０．３Ｎの組成を有する化合物膜を約２．５ｎｍの略均一な膜厚で成膜することができる。
【０１３５】
すなわち、前述したように、ＮＨ_３ガスの供給およびＴｉＣｌ_４ガスの供給を交互に５回ずつ繰り返す一連のシーケンスを行った後、ＮＨ_３ガスの供給およびＡｌＣｌ_３ガスの供給を交互に２回ずつ繰り返す一連のシーケンスを行うことにより、合計約１０５秒で各ウェーハ２３の表面上に約２．５ｎｍの膜厚を有するＴｉ_０．７Ａｌ_０．３Ｎ膜を略均一に成膜することができる。これら２種類のシーケンスからなる合計約１０５秒のシーケンスを１サイクルとし、これを３０回繰り返すことにより、各ウェーハ２３の表面上にＴｉ−Ａｌ−Ｎ膜を約７５ｎｍ堆積させる。これにより、本実施形態の成膜プロセスを終了とする。
【０１３６】
本発明者らによれば、以上説明した成膜プロセスにより、各ウェーハ２３に予め形成されていたコンタクトホールを、ボイド等が殆ど生じない状態で略完全に埋め込むことができることが確認された。また、これらのコンタクトホールを用いて形成された図示しないコンタクトプラグの表面は、約５４０℃の酸化性雰囲気下における熱処理でも殆ど酸化されず、コンタクト抵抗が十分に低いことが確認された。
【０１３７】
以上説明したように、この第３実施形態においては、前述した第１実施形態と同様の効果を得ることができる。また、前述したように、各ウェーハ２３を間に挟んで、反応容器１１の各ガスインジェクター６４，６５，６９が設けられている側と対向する側に複数個の排気孔１１を設ける。これにより、原料ガス、活性化ガス、およびパージガスを、それらの流れを略一定の向きに制御して流すことができる。この結果、各ガスの利用効率および排気効率をより高めることができるとともに、パージ時間をより短縮することが可能である。このような効果は、各ガスインジェクター６４，６５，６９から各排気孔１１にかけてボート２４に取り付けられた遮蔽板７２の遮蔽効果および整流効果、ならびに互いに離間されてボート２４に支持された各ウェーハ２３自体の整流効果と相乗効果を及ぼし合うことにより、一層高められる。各ガスインジェクター６４，６５，６９に設けられた複数個の吹き出し孔２７から各ウェーハ２３に向けて供給された原料ガス、活性化ガス、およびパージガスは、各ウェーハ２３および遮蔽板７２に案内されて各排気孔１１に向けて各ウェーハ２３を包むように流れる。したがって、この第３実施形態によれば、良質な化合物膜を極めて効率よく、かつ極めて容易に成膜できる。
【０１３８】
なお、本発明に係る成膜方法、成膜装置、および半導体装置の製造方法は、前述した第１〜第３の各実施形態には制約されない。本発明の趣旨を逸脱しない範囲で、それらの構成、あるいは工程などの一部を種々様々な設定に変更したり、あるいは各種設定を適宜、適当に組み合わせて用いたりして実施することができる。
【０１３９】
例えば、第１実施形態の成膜装置１を、その装置構成を変更することなく、原料としてテトライソプロポキシドチタン（ＴＴＩＰ）を用いることにより、ＴｉＯ_２膜やＴａ−Ｔｉ−Ｏ膜を成膜することも可能である。同様に、原料としてＡｌＣｌ_３を用いることで、Ａｌ_２Ｏ_３膜を成膜することも可能である。
【０１４０】
また、第１〜第３の各実施形態においては、各ウェーハ２３を、それらの表面（基板面）を互いに離間させた状態で、上下（縦）方向に積層するように反応容器１１内に配置したが、各ウェーハ２３の配置状態はこれに限るものではない。例えば、各ウェーハ２３を、それらの表面（基板面）を互いに離間させた状態で、左右（横）方向に並べるように反応容器１１内に配置しても構わない。また、各ウェーハ２３は、全て互いに平行となる姿勢で配置される必要は無い。それとともに、各ウェーハ２３は、隣接する各ウェーハ２３の間隔を全て均等な大きさに設定されて配置される必要は無い。各ウェーハ２３の配置方向、姿勢、間隔などは、反応容器１１内に導入されるガスの種類、重さ、性質、流れの方向、および各ガスが供給される順番などに応じて、各ウェーハ２３の表面上に化合物膜が略均一に適正な状態で成膜されるように適宜、適正な状態に設定して構わない。この場合、ボート２４を、各ウェーハ２３の配置方向、姿勢、間隔などを適宜、適正な状態に設定できる構成とするとよい。
【０１４１】
また、原料ガスインジェクター、活性化ガスインジェクター、およびパージガスインジェクターから供給される各ガスの供給圧力や吹き出し量などは、一律に等しい大きさに設定する必要は無い。各ガスのガスの種類、重さ、性質、流れの方向、および各ガスが供給される順番などに応じて、各ウェーハ２３の表面上に化合物膜が略均一に適正な状態で成膜されるように、各ガスインジェクターごとに適宜、適正な状態に設定して構わない。また、各ガスインジェクターに設けられた複数個の吹き出し孔２７からのガス供給圧力や吹き出し量などは、各孔２７の位置、すなわち各ウェーハ２３の配置位置に応じて適宜、適正な大きさに設定して構わない。例えば、各ウェーハ２３を、第１〜第３実施形態のように上下方向に積層するように配置した場合、各吹き出し孔２７からのガス供給圧力や吹き出し量などを、最上層のウェーハ２３から最下層のウェーハ２３にかけて、各ガスが略均等に供給されるように、各孔２７の高さごとに適正な大きさに設定するとよい。これにより、各ウェーハ２３の表面上に、化合物膜をより均一に、より適正な状態で成膜できる。
【０１４２】
また、第３実施形態においては、遮蔽板（整流板）７２を各ウェーハ２３の両側方に設けたが、これに限るものではない。例えば、遮蔽板７２を、各ガスインジェクターから各排気孔７１にかけて、各ウェーハ２３を支持しているボート２４の上方に設けても構わない。これにより、各ウェーハ２３に向けて供給される各ガスの遮蔽効果、整流効果をより向上させて、各ガスの利用効率、ひいては成膜効率を大幅に向上できる。あるいは、各ウェーハ２３を支持しているボート２４の上下両端部を、遮蔽効果および整流効果を発揮できる形状に形成するとよい。これにより、第１および第２実施形態のように、ボート２４に遮蔽板７２を、設けない場合でも、各ガスの利用効率および成膜効率を向上できる。また、そのような形状からなるボート２４を遮蔽板７２と併用すれば、各ガスの利用効率および成膜効率を極めて向上できるのはもちろんである。
【０１４３】
また、各ガスインジェクターから各ガスを供給している間は、反応容器１１内の不要なガスを排気系２５により反応容器１１の外へ積極的に排気する設定とするとよい。これにより、複数種類のガスを用いる場合でも、不要な気相間反応を大幅に低減させて、より良質な化合物膜を成膜できる。
【０１４４】
さらに、本発明に係る成膜方法、成膜装置、および半導体装置の製造方法を用いて製造可能な半導体装置は、ＤＲＡＭ等、現在、一般に普及している半導体装置には限られない。本発明に係る半導体装置の製造方法は、例えばＦｅＲＡＭなど、将来において発展が期待される各種の微細な半導体装置を製造する際にも十分適用可能なのはもちろんである。
【０１４５】
【発明の効果】
本発明に係る成膜方法および成膜装置によれば、処理室内のパージを短時間で容易に行うことができるので成膜作業の長時間化を容易に抑制できるとともに、ガスの使用効率を容易に向上でき、かつ、複数種類のガス同士の相互反応を容易に抑制できる。したがって、本発明に係る成膜方法によれば、ＡＬＤ法を用いてバッチ式処理により成膜作業を行う際に、良質な化合物膜を効率よく、かつ容易に成膜できる。
【０１４６】
また、本発明に係る半導体装置の製造方法によれば、本発明に係る成膜方法により成膜された化合物膜を用いることにより、半導体装置の内部に組み込まれる各種の微細な半導体素子などを高い品質で効率よく、かつ容易に形成して、半導体装置の品質および歩留まりを容易に向上させることができる。したがって、本発明に係る半導体装置の製造方法によれば、良質な化合物膜を有する良質な半導体装置を効率よく、かつ容易に製造できる。
【図面の簡単な説明】
【図１】第１実施形態に係る成膜装置を簡略化して示す図。
【図２】第１実施形態に係る成膜方法のシーケンスを示す図。
【図３】基板上にＴａ_２Ｏ_５膜が成膜される仕組みを模式的に示す工程断面図。
【図４】Ｔａ_２Ｏ_５膜を成膜する際に発生するパーティクルの成膜サイクルに対する依存性をグラフにして示す図。
【図５】第２実施形態に係る成膜装置を簡略化して示す図。
【図６】第２実施形態に係る成膜方法のシーケンスを示す図。
【図７】第２実施形態に係る成膜方法により穴の内部および周囲に成膜されたＳＴＯ膜を簡略化して示す断面図。
【図８】第３実施形態に係る成膜装置を簡略化して示す図。
【図９】第３実施形態に係る成膜方法のシーケンスを示す図。
【図１０】従来の技術に係る成膜装置を簡略化して示す斜視図。
【図１１】従来の技術に係る成膜方法のシーケンスを示す図。
【図１２】従来の技術に係る他の成膜装置を簡略化して示す斜視図。
【符号の説明】
１，３１，５１…成膜装置
２，３２，５２…原料ガス供給系
５，５６…活性化ガス供給系
１０…ＰＥＴガスインジェクター（原料ガス供給治具）
１１…反応容器（処理室）
１７…Ｈ_２Ｏガスインジェクター（活性化ガス供給治具）
１９…Ｏ_２ガスインジェクター（パージガス供給治具）
２０…パージガス供給系
２３…ウェーハ（被処理基板）
２４…ボート（基板支持具）
２７…吹き出し孔
２８…Ｔａ_２Ｏ_２膜（化合物膜）
４１…Ｓｒガスインジェクター（原料ガス供給治具）
４６…ＴＴＩＰガスインジェクター（原料ガス供給治具）
４７…ＳｒＴｉＯ_３膜（化合物膜）
６４…ＴｉＣｌ_４ガスインジェクター（原料ガス供給治具）
６５…ＡｌＣｌ_３ガスインジェクター（原料ガス供給治具）
６９…ＮＨ_３ガスインジェクター（活性化ガス供給治具）
７１…排気孔
７２…遮蔽板（整流板、整流部材）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for forming a compound thin film, and more particularly, to a method for forming a thin film of a compound such as BST, STO, (Ti, Al) N, and Ta—Ti—O by using an atomic layer deposition (ALD) method. The present invention relates to a film forming method and a film forming apparatus capable of forming a film in a batch system, and a method for manufacturing a semiconductor device using the same.
[0002]
[Prior art]
In recent years, with the downsizing of electronic devices, the arrangement of each element has been changed from a planar arrangement to a three-dimensional arrangement in order to reduce the projected area of each element constituting the electronic device and not to reduce the characteristics of each element. The need to change to is increasing. In particular, it is necessary to secure a predetermined capacitor capacity of the capacitor element so that the S / N ratio is not reduced even when the minimum processing size of the integrated circuit is reduced. In the 4MDRAM and subsequent generations, a three-dimensional capacitor element such as a so-called stack cell or trench cell is employed. As the degree of integration increases, it is becoming inevitable to employ a capacitor element having a more complicated three-dimensional shape.
[0003]
Further, the fact that the element is made three-dimensionally means that the aspect ratio of a contact hole that connects between layers of a plurality of wirings having a multilayer structure substantially increases. In this case, it is required to uniformly form a plug electrode film, a barrier metal film, and the like in a contact hole having a high aspect ratio.
[0004]
On the other hand, as the projected area of the device becomes smaller, it is naturally required to make various films used in the device thinner. For example, thinning of a compound film composed of a plurality of constituent elements, and in many cases, including a plurality of metal elements as constituent elements has been demanded. Specifically, the capacitor dielectric film is made of Ta, which can greatly reduce the equivalent oxide film thickness from a general NO film. ₂ O ₅ Film, high dielectric constant thin film such as Ta-Ti-O film, Ba-Sr-Ti-O (BST) film, Sr-Ti-O (STO) film, or Pb-Zr-Ti-O (PZT) film is there. The barrier metal film includes a TiN film, a TaN film, a (Ti, Al) N film and a (Ta, Si) N film exhibiting stronger oxidation resistance than a WN film or the like. Further, as a gate insulating film exhibiting a high dielectric constant, Al ₂ O ₃ A Hf-Si-O film, a Zr-Si-O film, or the like.
[0005]
In addition, as described above, as the device becomes more three-dimensional, it is required that these films be formed while maintaining good step coverage. Further, in consideration of the mixed mounting of elements on a system LSI or the like, a film forming method that does not depend on the mask pattern of the LSI or the coverage of the elements is required.
[0006]
When a generally used thermal CVD method is used to form the above-described multi-component compound film with good step coverage, there are the following problems.
[0007]
In order to form a multi-component compound film with good step coverage by a thermal CVD method, it is necessary to form a film under conditions for controlling the surface reaction. However, under such conditions, the film composition to be obtained is determined by the chemical reaction on the film surface, and therefore, the desired film quality and film composition are not always obtained. In particular, inside a deep contact hole or the like, since the diffusion coefficient, chemical reaction rate coefficient, or surface migration rate differs depending on the raw material, the composition may be different between the top and bottom of the hole. Further, under the surface reaction rate-determining condition, the film formation strongly depends on the film formation temperature, so that the substrate temperature varies depending on the state of the base of the film, for example, the coverage of wirings, electrodes, or contact holes. In particular, when the mask pattern or the element coverage changes frequently as in a system LSI or the like, there is a problem that frequent deposition conditions must be set in accordance with the change.
[0008]
As a method of solving such a problem of the thermal CVD method, a so-called Atomic Layer Deposition (ALD) method has recently been receiving attention. Even when a compound film containing a plurality of types of metal elements is formed as described above, composition control is easy because the ALD method forms a film for each element. Also, although not usually thermal decomposition, the ALD method forms the atomic layer under almost completely the conditions of the surface reaction control, so that the step coverage is very good. However, the ALD method generally has a problem that the film formation time is long. The ALD method typically uses H ₂ O, NH ₃ , O ₃ Supply of active gas, etc., purge by evacuation, AlCl ₃ Supply of metal source gas, etc., purging by evacuation, ₂ O, NH ₃ , O ₃ By repeatedly performing a sequence of supplying an active gas such as a plurality of times, a film is formed in units of atomic layers, and the film formation time tends to be originally long. In particular, when a plurality of types of metal source gases are used, it is necessary to control the composition in a multi-component system in order to suppress the mutual reaction between the metal source gases. In this case, the purge time by evacuation becomes long.
[0009]
Therefore, in the ALD method, an apparatus capable of forming a film by batch processing is being studied in order to reduce a net process time (RPT) per wafer.
[0010]
[Problems to be solved by the invention]
FIG. 10 shows that Al processing was performed by batch processing using the ALD method. ₂ O ₃ 1 shows an example of an apparatus for forming a film. In this film forming apparatus 101, a normal ALD apparatus is enlarged so that a film forming process can be performed on a plurality of wafers (substrates) 102 simultaneously. Al ₂ O ₃ The supply state of the various source gases for the film into the processing chamber (reaction vessel) 103 is controlled by a gas supply system 104. Each raw material gas is passed through a current plate 106 provided on one end side (entrance side) of the chamber 105 and is supplied into the processing chamber 103 in a laminar flow. The current plate 106 is indispensable because the size of the chamber 105 is increased. Each source gas supplied into the processing chamber 103 passes through each wafer 102, and is then exhausted from the other end side (exit side) of the chamber 105 by the exhaust system 107.
[0011]
FIG. 11 shows an example of a sequence of a film forming process performed using the film forming apparatus 101.
[0012]
In this example, the size of the chamber 105 is increased, and there is a problem that the purge time becomes longer in order to suppress the reaction on the upstream side of the current plate 106. Further, since the size of the chamber 105 is increased, there is a problem that the consumption rate of each source gas increases. This is because each source gas that does not reach the surface of the substrate 102 is exhausted without contributing to film formation, and in order to secure a partial pressure of each source gas required on the surface of the substrate 102, This is because the partial pressure of each source gas must be increased. As the consumption rate of the source gas increases, the film formation efficiency decreases, the film formation cost increases, and the manufacturing cost of the semiconductor device also increases. In general, in the ALD method, the dead space in the chamber 105 is reduced as much as possible in order to shorten the purge time between each sequence. Then, it becomes difficult to perform the batch processing, and it is difficult to achieve both the batch processing and the shortening of the purge time. Further, in the ALD method, generally, the uniformity of the gas flow is not given much importance. However, in the batch processing, since it is necessary to cause the ALD reaction on the surface of each wafer 102 as uniformly as possible, equipment for uniformizing the gas flow such as the rectifying plate 106 is required. This makes it more difficult to shorten the purge time.
[0013]
In FIG. 12, similarly to the film forming apparatus 101, Al processing is performed by batch processing using the ALD method. ₂ O ₃ Another example of an apparatus for forming a film is shown. In this film forming apparatus 201, in order to suppress an increase in the purge time due to the batch processing, a gas purge that can be shortened easily is adopted instead of a vacuum purge that requires a long time. At the same time, in the film forming apparatus 201, a plurality of gas injectors 202 are set to rotate on a susceptor 203 on which a plurality of wafers 102 are mounted. Thus, the RPT of the film forming apparatus 201 is reduced. In the case of the film forming apparatus 201, each of the four gas injectors 202 has AlCl as a metal source gas. ₃ Gas, argon (Ar) gas as a purge gas, H as a reaction gas ₂ O gas and Ar gas as a purge gas are supplied one by one. Each gas is constantly supplied from the gas injector 202 to the surface of each wafer 102 in order without switching the type of gas. That is, in the film forming apparatus 201, the four gas injectors 202 are rotated to change the type of gas supplied to each wafer 102 to, for example, AlCl ₃ , Ar, H ₂ O, Ar, AlCl again ₃ In this order, ALD film formation is performed.
[0014]
However, this example has the following problem. In the film forming apparatus 201, since a plurality of types of gases are always supplied simultaneously into the chamber 204, it is difficult to separate each gas in the chamber 204. Therefore, a gas phase reaction between each gas in the chamber 204 or H ₂ It is difficult to suppress undesired reactions in the gas system, such as the deposition of Al on the O gas injector 202a, within an appropriate allowable range. In particular, in the case of forming a compound film including many constituent elements such as a BST film and a PZT film, the types of source gases are increased, and it is extremely difficult to suppress the reaction between the source gases. At the same time, there is a problem that the device configuration is complicated. Further, according to the film forming apparatus 201 and the film forming method, the film quality of the compound film is likely to be deteriorated, and the quality of the whole semiconductor device may be deteriorated. Then, the manufacturing yield of the semiconductor device may be reduced, the manufacturing efficiency of the semiconductor device may be reduced, and the manufacturing cost of the semiconductor device may be increased.
[0015]
The present invention has been made to solve the above-described problems, and an object of the present invention is to perform purging in a short time when performing a film forming operation by batch processing using an ALD method. By easily performing, it is possible to easily suppress the prolongation of the film formation work, easily improve the gas use efficiency, and furthermore, easily suppress the mutual reaction between a plurality of types of gases, and obtain a high-quality compound film. It is an object of the present invention to provide a film forming method and a film forming apparatus capable of forming a film efficiently and easily. It is another object of the present invention to provide a method for manufacturing a semiconductor device that can efficiently and easily manufacture a high-quality semiconductor device having a high-quality compound film.
[0016]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a film forming method according to the present invention is a film forming method for forming a compound film at the atomic layer level on surfaces of a plurality of substrates to be processed, A first step of arranging the respective substrates to be separated from each other in a reaction vessel in which the processing is performed, and arranging the substrates in parallel along a thickness direction; Supply gas from a plurality of gas supply jigs for supplying an activation gas for activating a film formation reaction, and supplying another activation gas to the other gas supply jigs. A second step of supplying a purge gas from a jig; and a third step of switching the gas supplied from the activation gas supply jig from the activation gas to the purge gas and supplying the purge gas from another gas supply jig. And the adjacent each The source gas is supplied from a source gas supply jig that supplies a source gas serving as a main source of a compound film to be formed, and the purge gas is supplied from another gas supply jig. And a fifth step of switching the gas supplied from the source gas supply jig from the source gas to the purge gas and supplying the purge gas from another gas supply jig, and The method is characterized in that the second step to the fifth step are repeated a plurality of times.
[0017]
In this film forming method, a plurality of substrates to be processed are spaced apart from each other and arranged in parallel along the thickness direction in a reaction vessel where a film forming process is performed, and then directed toward each adjacent substrate to be processed. The step of alternately supplying the activation gas and the source gas while supplying the purge gas is repeated a plurality of times. As a result, a compound film is formed on the surfaces of a plurality of substrates to be processed at once at the atomic layer level. According to this film forming method, since the purge gas is used when purging the inside of the reaction vessel, the purging can be easily performed in a short time, and the prolongation of the film forming operation can be easily suppressed. In addition, a plurality of substrates to be processed are arranged in a reaction vessel while being spaced apart from each other along the thickness direction, and the activation gas and the source gas are supplied between adjacent substrates to be processed. Can be easily used. Furthermore, the supply of the activation gas and the supply of the source gas are performed exclusively, and the purge gas is also supplied between the adjacent substrates to be processed when supplying the activation gas and the source gas. It is possible to easily suppress the mutual reaction between the kinds of gases.
[0018]
In order to solve the above problems, a film forming method according to the present invention is a film forming method in which a compound film is collectively formed on a surface of a plurality of substrates to be processed. In order to activate the film formation reaction while continuously supplying a purge gas from the direction substantially parallel to the substrate surfaces toward the respective substrates to be processed, to be arranged side by side along the thickness direction so as to be separated from each other. And a source gas that is a main source of a compound film to be formed is alternately supplied.
[0019]
In this film forming method, a plurality of substrates to be processed are arranged side by side in the thickness direction while being separated from each other, and a purge gas is continuously supplied to each substrate to be processed from a direction substantially parallel to the substrate surface. An activation gas for activating a film formation reaction and a source gas as a main material of a compound film to be formed are alternately supplied while being supplied. Thus, compound films are collectively formed on the surfaces of the plurality of substrates to be processed. According to this film forming method, since the purge gas is used when performing the purge, the purge can be easily performed in a short time, and the prolongation of the film forming operation can be easily suppressed. In addition, a plurality of substrates to be processed are spaced apart from each other and arranged along the thickness direction, and an activating gas and a source gas are supplied to each of the substrates to be processed from a direction substantially parallel to the substrate surface. Therefore, the gas use efficiency can be easily improved. Furthermore, since the activation gas and the source gas are alternately supplied while the purge gas is continuously supplied to each substrate to be processed, the mutual reaction between a plurality of types of gases can be easily suppressed.
[0020]
Further, in order to solve the above problem, the film forming method according to the present invention includes a process chamber in which a film forming process for collectively forming a compound film on a surface of a plurality of substrates to be processed is performed. The substrates to be processed are arranged side by side in the thickness direction with their surfaces separated from each other, and after purging the processing chamber by supplying a purge gas into the processing chamber in which each of the substrates is disposed, purging is performed. Along with continuing to supply the purge gas from each of the substrates to be processed disposed in the processing chamber in a direction substantially parallel to the substrate surface, the activation gas for activating a film formation reaction is Supplying on the surface of each substrate to be processed, while supplying the purge gas toward each substrate to be processed, and cutting off the supply of the activation gas, and toward each substrate to be processed, the substrate surface From a direction almost parallel to the front By supplying the major raw material comprising the raw material gas of a compound film on the surface of each substrate to be treated, is characterized in that for forming the compound layer the on the surface of the substrate to be processed.
[0021]
In this film forming method, since a purge gas is used when purging the processing chamber where the film forming process is performed, the purging can be easily performed in a short time, and the prolongation of the film forming operation can be easily suppressed. In the processing chamber, a plurality of substrates to be subjected to a film forming process are arranged side by side in a thickness direction while being separated from each other, and are directed toward each of the substrates to be processed in a direction substantially parallel to their substrate surfaces. Since the activation gas and the raw material gas are supplied from, the gas use efficiency can be easily improved. Furthermore, while the supply of the activation gas and the supply of the source gas are performed exclusively, and when the activation gas and the source gas are supplied, the supply of the activation gas and the source gas is performed in a direction substantially parallel to the surfaces of the substrates to be processed. Since the purge gas is supplied, the mutual reaction between a plurality of types of gases can be easily suppressed.
[0022]
In carrying out the film forming method according to the present invention, some of the steps and the like may be set as described below.
[0023]
The supply of the activation gas and the supply of the source gas are alternately repeated a plurality of times.
[0024]
For each of the substrates to be processed, between the state in which the activation gas is being supplied and the state in which the source gas is being supplied, for each of the substrates to be processed, their substrate surfaces Only the purge gas is supplied from a parallel direction.
[0025]
A plurality of the source gases are used, and the supply of the activation gas and the supply of the source gas are repeated a plurality of times in a predetermined order for each type of the source gas.
[0026]
Each of the gases is directed toward each of the substrates to be processed, when supplied from a direction parallel to the surface of the substrates, between each of the substrates to be processed and each surface of each of the substrates to be processed. Each of the above gases is supplied to the apparatus.
[0027]
Among the purge gas, the activating gas, and the source gas, the magnitude of the pressure when at least the source gas is supplied into the processing chamber is set to be 10 times or more the magnitude of the pressure in the processing chamber.
[0028]
The purge gas, the activation gas, and the source gas are exhausted to the outside of the processing chamber from a side opposite to a side on which the gases are supplied, with the substrate to be processed interposed therebetween.
[0029]
The activating gas is H ₂ O, O ₃ , NH ₃ At least one of them.
[0030]
The raw material gas includes an alkaline earth metal cyclopentadienyl compound and titanium alkoxide compound, or a composition formula of C ₁₁ H ₁₉ O ₂ And a dipivaloyl methanate complex containing an alkoxyl group.
[0031]
The cyclopentadienyl compound also includes a substance in which a part of hydrogen bonded to a cyclopentadienyl ring is substituted by an alkyl group or an alkoxyl group.
[0032]
The purge gas contains O ₂ And N ₂ O is included.
[0033]
In carrying out the film forming method according to the present invention, by setting some of the steps and the like as described above, the film forming operation can be performed for a longer time and the mutual reaction between a plurality of types of gases can be more easily performed. And the gas use efficiency can be more easily improved. Therefore, a high-quality compound film can be formed more efficiently and more easily.
[0034]
Further, in order to solve the above problem, a film forming apparatus according to the present invention includes a processing chamber provided for a film forming process, and a plurality of substrates to be processed on which the film forming process is performed. A substrate support that can be arranged and supported along the thickness direction while being separated, a source gas that is a main source of a compound film that is collectively formed on the surface of each of the substrates to be processed, and the processing chamber A source gas supply jig for supplying a purge gas for purging the substrate toward each of the substrates to be processed from a direction substantially parallel to a surface of the substrate, and a source gas for supplying the source gas to the source gas supply jig. A gas supply system, an activating gas for activating a film forming reaction when the compound film is formed, and the purge gas are directed toward the respective substrates to be processed from a direction substantially parallel to their substrate surfaces. An activation gas supply jig for supplying the activated gas; An activation gas supply system for supplying an activation gas to the activation gas supply jig; and a source gas supply jig and the activation gas supply by selectively switching the purge gas between the source gas and the activation gas. And a purge gas supply system for supplying to the jig.
[0035]
In this film forming apparatus, since the processing chamber used for the film forming process is purged using the purge gas, the purging can be easily performed in a short time, and the prolongation of the film forming operation can be easily suppressed. Further, a plurality of substrates to be subjected to the film forming process are arranged in the processing chamber while being separated from each other using a substrate support and supported side by side along the thickness direction. Then, the source gas and the activation gas are supplied using the source gas supply jig and the activation gas supply jig. Thereby, the gas use efficiency can be easily improved. Further, the source gas supply jig and the activation gas supply jig are selectively switched between the source gas, the activation gas, and the purge gas by the purge gas supply system, and are substantially flush with their substrate surfaces toward the respective substrates to be processed. A purge gas can be supplied from a parallel direction. Thereby, the mutual reaction between a plurality of types of gases can be easily suppressed.
[0036]
In implementing the film forming apparatus according to the present invention, a part of the configuration and the like may be set as described below.
[0037]
The activation gas supply jig and the activation gas supply system are provided independently for each type of the activation gas, and the activation gas supply system converts the activation gas for each type. It is set so that it can be supplied to the activation gas supply jig independently.
[0038]
A purge gas supply jig for supplying the purge gas toward each of the substrates to be processed from a direction substantially parallel to the substrate surface is provided, and the purge gas supply system supplies the purge gas to the purge gas supply jig. It is set to be possible.
[0039]
The source gas supply jig and the activation gas supply jig are arranged along the direction in which the substrates to be processed are arranged, between the adjacent substrates to be processed and the substrates of the substrates to be processed. A plurality of blowout holes for supplying the respective gases toward the respective substrates to be processed are provided at positions substantially facing at least one of the surfaces.
[0040]
In the processing chamber, the source gas supply jig and the activating gas supply jig are provided with the respective substrates to be processed supported by the substrate support and arranged in the processing chamber therebetween. A position substantially opposite to at least one of the adjacent substrates to be processed and the substrate surface of each of the substrates to be processed, along the direction in which the substrates to be processed are arranged, A plurality of exhaust holes for exhausting the source gas, the activating gas, and the purge gas out of the processing chamber, and the substrate support includes a source gas supply jig and the active component. A rectifying member is provided from the vicinity of the chemical gas supply jig to the vicinity of each of the exhaust holes to surround each of the substrates to be processed from their sides.
[0041]
In carrying out the film forming apparatus according to the present invention, by setting a part of the configuration and the like to various settings as described above, it is possible to make the film forming work longer and to facilitate the mutual reaction between a plurality of types of gases. And the gas use efficiency can be more easily improved. Therefore, a high-quality compound film can be formed more efficiently and more easily.
[0042]
In order to solve the above problems, a method for manufacturing a semiconductor device according to the present invention is characterized in that a semiconductor element is formed using a compound film formed by the film forming method according to the present invention. is there.
[0043]
In this method of manufacturing a semiconductor device, a semiconductor element is formed using a compound film formed by the film forming method according to the present invention. This makes it possible to efficiently form various kinds of fine semiconductor elements and the like incorporated inside the semiconductor device with high quality, thereby improving the quality and yield of the semiconductor device.
[0044]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0045]
(First Embodiment)
First, a first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a diagram schematically illustrating a film forming apparatus according to the first embodiment. FIG. 2 is a diagram showing a sequence of the film forming method according to the first embodiment. FIG. 3 shows Ta on the substrate. ₂ O ₅ FIG. 4 is a process cross-sectional view schematically illustrating a mechanism in which a film is formed. FIG. ₂ O ₅ FIG. 7 is a graph showing the dependence of particles generated when forming a film on the film forming cycle.
[0046]
In the present embodiment, specifically, the atomic layer deposition (ALD) method is performed by a batch process to obtain Ta as a compound film. ₂ O ₅ Film forming method and film forming apparatus for forming a film, Ta ₂ O ₅ Film formation conditions and obtained Ta ₂ O ₅ The characteristics of the film will be described. Further, a method of manufacturing a semiconductor device using the film forming method and the film forming apparatus of the present embodiment will be described.
[0047]
In the film forming process of this embodiment, a pentaethoxy tantalum (PET) gas is used as a source gas containing a main source of the compound film. Further, H is used as an activating gas for activating the film forming reaction. ₂ O gas is used. Further, oxygen (O 2) is used as a purge gas. ₂ ) Gas and argon (Ar) gas.
[0048]
First, a film forming apparatus 1 according to the present embodiment will be described with reference to FIGS.
[0049]
FIG. 1A is a diagram illustrating a schematic configuration of the film forming apparatus 1 viewed from the front or side. FIG. 1B is a plan view showing the film forming apparatus 1 viewed from the direction of a solid arrow in FIG. The film forming apparatus 1 mainly includes a source gas supply system 2 and a reaction system 3. The source gas supply system 2 includes a PET gas supply system 4 and H ₂ Activated gas supply system (H ₂ O gas supply system) 5 and the like. In the present embodiment, the activation gas supply system 5 is configured as a part of the source gas supply system 2, but it is needless to say that they may be configured as individual systems independent of each other.
[0050]
The PET gas supply system 4 mainly includes a PET raw material container 6, a PET liquid flow rate control device 7, a PET vaporizer 8, and the like. The vaporization temperature is about 180 ° C. The PET gas vaporized by the PET vaporizer 8 passes through a PET gas pipe 9 heated to about 200 ° C., and is sent to a quartz PET gas injector 10 as a source gas supply jig. The PET gas injector 10 is provided in a processing chamber (reaction vessel) 11 where a film forming process is performed, and the PET gas is supplied (introduced) into the reaction vessel 11 via the PET gas injector 10. In the vicinity of the connection between the PET gas pipe 9 and the PET gas injector 10, that is, at the root of the PET gas injector 10, the gas passing through the PET gas injector 10 can be selectively switched to PET gas or Ar gas. Is provided with a source gas supply system switching valve 12.
[0051]
H ₂ The O gas supply system 5 mainly includes H ₂ O container 13, this H ₂ H for heating the O container 13 to about 80 ° C. ₂ O heating device 14, and H ₂ It comprises a gas flow control device 15 for O gas. H ₂ O gas is H heated to about 150 ° C. ₂ After passing through the O gas pipe 16, quartz H ₂ It is sent to the O gas injector 17. H ₂ The O gas injector 17 is provided in the reaction vessel 11 and ₂ O gas is H ₂ It is supplied into the reaction vessel 11 via the O gas injector 17. H ₂ O gas pipe 16 and H ₂ Near the connection with the O gas injector 17, that is, H ₂ At the base of the O gas injector 17, H ₂ The gas passed through the O gas injector 17 is H ₂ O gas, Ar gas, or O gas ₂ An activation gas supply system switching valve 18 is provided so that the gas can be selectively switched.
[0052]
In addition to the two gas injectors 10 and 17 described above, an Ar gas and an O 2 gas ₂ O as a purge gas supply jig that can selectively supply gas ₂ A gas injector 19 is provided in the reaction vessel 11. That is, the film forming apparatus 1 includes a total of three gas injectors 10, 17, and 19. In the film forming apparatus 1, the three gas injectors 10, 17, and 19 are supplied with Ar gas or O gas. ₂ A purge gas supply system 20 for supplying gas is provided. Ar gas and O ₂ The gas passes through a purge gas pipe 21 of the purge gas supply system 20 and is sent to each of the gas injectors 10, 17, and 19.
[0053]
In the purge gas supply system 20, O ₂ O connected to the gas injector 19 ₂ A part of the gas system is connected to the ozonizer 22. As a result, the purge gas supply system 20 passes through the ozonizer 22 ₃ / O ₂ Mix gas with O ₂ It is possible to supply the gas into the gas injector 19 and the reaction vessel 11.
[0054]
On the other hand, the reaction system 3 includes a reaction vessel 11 capable of accommodating a plurality of substrates (wafers) 23 to be subjected to a film forming process at the same time, and a substrate capable of collectively supporting the wafers 23 in the reaction vessel 11. It comprises a boat 24 as a support, an exhaust system 25 for exhausting the raw material gas, the activation gas, and the purge gas supplied into the reaction vessel 11 out of the reaction vessel 11. The so-called hot-wall type reaction vessel provided with a vessel heating device 26 that can heat the plurality of wafers 23 accommodated in the reaction vessel 11 substantially uniformly in the reaction vessel 11 of the present embodiment. 11 are employed. In addition, the boat 24 can support the wafers 23 in a state where the wafers 23 are arranged side by side so as to be stacked in parallel with each other and along the thickness direction while separating their surfaces (substrate surfaces) by a predetermined interval. It has a structure. Further, the shape of the boat 24 can be selectively selected according to the number of the wafers 23, or the type of the film to be formed, the thickness of the film, and the like so that the film forming process is efficiently performed in an appropriate state. Is preferred.
[0055]
Further, the PET gas injector 10, H ₂ O gas injector 17, and O ₂ The gas injector 19 feeds a plurality of wafers 23 accommodated in the reaction vessel 11 from a direction substantially parallel to the substrate surface, from a PET gas or H gas. ₂ O gas, O ₂ A plurality of blowout holes 27 are provided so that gas and Ar gas can be supplied. Specifically, the PET gas injector 10, H ₂ O gas injector 17, and O ₂ In the gas injector 19, each of the wafers 23 is disposed between the adjacent wafers 23 and at a position substantially opposed to at least one of the substrate surfaces of the wafers 23 along the direction in which the wafers 23 are separated from each other and stacked. A plurality of blowing holes 27 for supplying gas toward each wafer 23 are provided. That is, each of the three gas injectors 10, 17, and 19 is formed as a porous gas injector. Thus, each of the gas injectors 10, 17, and 19 can supply each gas intensively and efficiently toward the surface of the plurality of wafers 23 or between the wafers 23. At the same time, toward the surface of each wafer 23 or between each wafer 23, O ₂ By supplying the gas or the Ar gas, unnecessary gas can be quickly and easily removed from near the surface of each wafer 23 or between the wafers 23.
[0056]
Next, a film forming method according to the present embodiment will be described with reference to FIGS. Specifically, the film forming method according to the present embodiment uses the film forming apparatus 1 to form a Ta film as a compound film in the following sequence. ₂ O ₅ The film 28 is formed.
[0057]
A plurality of wafers 23 are introduced into the reaction vessel 11 and supported by a boat 24 disposed in the reaction vessel 11. Subsequently, the container heating device 26 is used to heat the reaction container 11 substantially uniformly so that the atmosphere in the reaction container 11 and the temperature of each wafer 23 become about 280 ° C. At the same time, the PET gas injector 10, H ₂ O gas injector 17, and O ₂ About 1 SLM of Ar gas is supplied into the reaction vessel 11 from the gas injector 19, and the pressure in the reaction vessel 11 is maintained at about 0.6 Torr. The heat recovery time is about 10 minutes. After confirming that the temperature in the reaction vessel 11 (furnace temperature) is stable at about 280 ° C. ± 10 ° C., while maintaining the pressure in the vessel at about 0.6 Torr, based on the sequence shown in FIG. Is performed.
[0058]
First, in the reaction vessel 11, H ₂ O gas injector 17 to H ₂ About 500 sccm of O gas is introduced for about 45 seconds, and the PET gas injector 10 and O gas are introduced. ₂ Ar gas is supplied from the gas injector 19 at a rate of about 500 sccm for about 45 seconds. H introduced into the reaction vessel 11 ₂ The O gas is adsorbed on the surface of each wafer 23 as shown in FIG.
[0059]
Next, the PET gas injector 10 and the O ₂ While supplying Ar gas from the gas injector 19, H ₂ The gas supplied from the O gas injector 17 is switched to Ar gas. Then, the PET gas injector 10, O ₂ Gas injector 19 and H ₂ Ar gas is supplied from the O gas injector 17 at about 1 SLM for about 20 seconds. Thereby, the space between the adjacent wafers 23 is purged for about 20 seconds.
[0060]
Next, under the condition that the flow rate of the PET raw material is about 3 sccm, a PET gas is introduced into the reaction vessel 11 from the PET gas injector 10 for about 20 seconds. At this time, the internal pressure of the PET gas injector 10 is about 23 Torr. Also, O ₂ Gas injector 19 and H ₂ From the O gas injector 17, Ar gas is supplied into the reaction vessel 11 at about 500 sccm for about 20 seconds each.
[0061]
Normally, PET decomposition reaction hardly occurs at about 280 ° C., but H ₂ Since O is adsorbed, the PET gas arriving at the surface of each wafer 23 is adsorbed H as shown in FIG. ₂ A hydrolysis reaction occurs with O. As a result, an oxide film of Ta having a thickness of about 0.3 nm is formed on the surface of each wafer 23. 3A and 3B, the surface of the wafer 23 is made of Ta. ₂ O ₅ To facilitate understanding of the mechanism by which the film 28 is formed, H ₂ O molecules and PET molecules are schematically depicted.
[0062]
Next, O ₂ Gas injector 19 and H ₂ The gas supplied from the PET gas injector 10 is switched to the Ar gas while the Ar gas is supplied from the O gas injector 17 into the reaction vessel 11. Then, the PET gas injector 10, O ₂ Gas injector 19 and H ₂ Ar gas is supplied from the O gas injector 17 at about 1 SLM for about 10 seconds. Thus, the space between the adjacent wafers 23 is purged for about 10 seconds.
[0063]
Next, while supplying Ar gas from the PET gas injector 10 into the reaction vessel 11, ₂ Gas injector 19 and H ₂ The gas supplied from the O gas injector 17 is O ₂ Switch to gas. Then, Ar gas is supplied from the PET gas injector 10 into the reaction vessel 11 and O ₂ Gas injector 19 and H ₂ From the O gas injector 17, O ₂ The gas is supplied at about 1 SLM for about 20 seconds each. This allows Ar gas and O 2 to flow between adjacent wafers 23. ₂ Purge with gas for about another 20 seconds.
[0064]
Next, while supplying Ar gas from the PET gas injector 10 into the reaction vessel 11, ₂ Gas injector 19 and H ₂ The gas supplied from the O gas injector 17 is switched to Ar gas. Then, the PET gas injector 10, O ₂ Gas injector 19 and H ₂ Ar gas is supplied from the O gas injector 17 at a rate of about 1 SLM for about 5 seconds. As a result, the space between the adjacent wafers 23 is purged for about 5 seconds.
[0065]
By the above-described sequence (procedure), the TaO film 28 having a thickness of about 0.3 nm can be formed substantially uniformly on the surface of each wafer 23 in about 120 seconds. This sequence of about 120 seconds is defined as one cycle, and this cycle is repeated 30 times, so that Ta on the surface of each wafer 23 is formed. ₂ O ₅ A film 28 is deposited to about 9 nm. Then O ₂ O from gas injector 19 ₃ / O ₂ The mixed gas is introduced into the reaction vessel 11 and ₂ O ₅ By performing a predetermined process on the film 28, the film forming process of this embodiment is completed. During the execution of the film forming process, the unnecessary gases are supplied to the reaction vessel 11 and the pressure, temperature, atmosphere components, and the like in the reaction vessel 11 are maintained in appropriate states. As described above, the air is exhausted from the exhaust system 25 to the outside of the reaction vessel 11 as appropriate.
[0066]
FIG. 4 shows that the cross-sectional area (opening area) of each blowout hole 27 provided in the PET gas injector 10 was experimentally changed, and the number of film formations and Ta were changed. ₂ O ₅ The result of monitoring the correlation with the particles of the film 28 is shown. As shown in the table in FIG. 4, by changing the cross-sectional area of each blowout hole 27, Ta ₂ O ₅ It can be seen that the internal pressure of the PET gas injector 10 changes when the film 28 is formed. At the same time, when the internal pressure of the PET gas injector 10 is reduced to 5 Torr or less, the number of particles increases as the number of film formation increases.
[0067]
According to a study conducted by the present inventors, when the inside of the PET gas injector 10 when particles increased was subjected to HF cleaning and ICP spectroscopic analysis was performed, Ta was found inside the PET gas injector 10. ₂ O ₅ It was found that film 28 had been deposited. This is because when the internal pressure of the PET gas injector 10 decreases, the H gas that has entered the inside of the injector 10 ₂ This means that O gas is adsorbed on the inner surface of the injector 10 and an ALD reaction occurs inside the injector 10. According to this result, in order to perform a film forming process based on the ALD method in an appropriate state, the PET gas injector 10 as a porous gas injector and the H ₂ O gas injector 17, and O ₂ Of the gas injectors 19, at least the PET gas injector 10 as a source gas injector is preferably formed in a shape such that the internal pressure of the injector during film formation is about 10 times or more the internal pressure of the reaction vessel 11. I understand.
[0068]
As described above, in the first embodiment, by employing the ALD film formation, even when the compound film 28 having a complicated three-dimensional shape is formed, precise control of the film composition during the film formation is performed. Is possible. Further, by adopting the ALD film formation, it is possible to realize good step coverage with the compound film 28. Further, since the source gas and the activation gas can be intensively supplied to the surface of each wafer 23 or between the wafers 23, the concentration of the source gas and the activation gas can be selectively increased only between the wafers 23. It is possible. Thereby, even when the amounts of the source gas and the activating gas are small, a sufficient ALD film forming reaction can be realized in an appropriate state, so that the use (use) efficiency of each gas can be improved. In addition, an increase in film formation cost due to an increase in the consumption rate of the source gas, and an increase in manufacturing cost of the semiconductor device can be suppressed.
[0069]
In addition, since a plurality of wafers 23 can be processed collectively by batch processing, a net process time (RPT) required for the film formation processing can be reduced. Further, the RPT can be shortened by employing a gas purge which requires only a short time for purging instead of a vacuum purging which generally takes time. In particular, since the adjacent wafers 23 function as rectifying plates, gas purging can be effectively performed. The function of each wafer 23 as a current plate is, of course, effective in increasing the use efficiency of each gas when supplying the raw material gas and the activating gas to each wafer 23.
[0070]
Further, during the film formation, the source gas or the activation gas is selectively switched and supplied while always supplying the purge gas between the wafers 23 and around them. Accordingly, there is almost no possibility that the film quality of the compound film 28 to be formed is deteriorated due to the progress of the film forming process in an unfavorable atmosphere.
[0071]
In addition, before the source gas is supplied to each wafer 23, an activating gas is attached to the surface of each wafer 23, so that the ALD reaction can be caused at a low temperature which is not normally possible. At the same time, by setting the internal pressure of the source gas injector 10 at the time of film formation to be at least 10 times higher than the pressure inside the reaction vessel 11, even if an oxidizing gas is There is almost no possibility that a gas phase reaction will occur with the remaining raw material gas. In addition, organic substances such as ligands in the compound film 28 to be formed can be efficiently desorbed.
[0072]
Furthermore, by employing a hot wall heating method, it is easy to heat a plurality of wafers 23 substantially uniformly and collectively. By employing the hot wall method, when a thin film is formed, the film forming temperature can be kept substantially constant without depending on the underlying structure of the wafer 23 or the mask pattern. Usually, in the hot wall type heating method, it is necessary to increase the heat recovery time, but in the ALD method, precise temperature control is not required. Therefore, in the film forming process of this embodiment, a long heat recovery time is not required, which is extremely effective in shortening the RPT. Further, since the apparatus configuration of the film forming apparatus 1 of the present embodiment is relatively simple, it is easy to change the apparatus configuration according to the type of the compound film to be formed.
[0073]
As described above, according to the first embodiment, a high-quality compound film can be efficiently and easily formed by performing a film forming operation by batch processing using the ALD method.
[0074]
Next, a method for manufacturing the semiconductor device according to the first embodiment of the present invention will be briefly described. The method for manufacturing a semiconductor device according to the present embodiment includes a compound film (Ta) formed by the film forming method and the film forming apparatus 1 according to the above-described embodiment. ₂ O ₅ The process includes a step of forming various fine semiconductor elements incorporated inside the semiconductor device by using the film 28. According to the film forming method and the film forming apparatus 1 described above, a high-quality compound film can be formed efficiently and easily. Therefore, according to the method of manufacturing a semiconductor device of the present embodiment, various fine semiconductor elements incorporated inside the semiconductor device can be formed efficiently and easily with high quality, and the quality and yield of the semiconductor device can be reduced. It can be easily improved. Therefore, according to the method of manufacturing a semiconductor device according to the first embodiment, a high-quality semiconductor device having a high-quality compound film can be efficiently and easily manufactured.
[0075]
(Second embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIGS. FIG. 5 is a diagram schematically illustrating a film forming apparatus according to the second embodiment. FIG. 6 is a diagram illustrating a sequence of a film forming method according to the second embodiment. FIG. 7 is a cross-sectional view schematically showing the STO film formed inside and around the hole by the film forming method according to the second embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0076]
In the present embodiment, specifically, by performing an atomic layer deposition (ALD) method in a batch process, a film forming method and a film forming apparatus for forming an STO film and a BST film as compound films, and a STO The film forming conditions of the film and the BST film and the characteristics of the obtained STO film and the BST film will be described.
[0077]
In the film forming process of the present embodiment, strontium bistriisopropylcyclopentadienyl (Sr (C ₅ -I-Pr ₃ H ₂ ) ₂ ), Barium bispentamethylcyclopentadienyl (Ba (C ₅ Me ₅ ) ₂ ) Of tetrahydrofuran (THF: C ₄ H ₈ O) A solution (solution concentration: 0.15 mol / liter) and a gas of titanium tetraisopropoxide (TTIP) are used. Further, H is used as an activating gas. ₂ O gas is used. Further, oxygen (O 2) is used as a purge gas. ₂ ) Gas and argon (Ar) gas.
[0078]
First, the film forming apparatus 31 of the present embodiment will be described with reference to FIGS.
[0079]
FIG. 5A is a diagram illustrating a schematic configuration of the film forming apparatus 31 viewed from the front or side. FIG. 5B is a plan view showing the film forming apparatus 31 viewed from the direction of the solid arrow in FIG. The film forming apparatus 31 mainly includes a source gas supply system 32 and a reaction system 33 as in the first embodiment described above. The source gas supply system 2 includes a Ba gas supply system 34, a Sr gas supply system 35, a TTIP gas supply system 36, and H ₂ It comprises an O gas supply system 5 and the like. Since the conditions for forming the Ba gas and the Sr gas are substantially the same, only the case where the Sr gas and its supply system 35 are formed, that is, the case where the STO film is formed, will be described below in order to avoid complication. Also, there is no appropriate abbreviation for the raw material containing Sr described above, and the use of a formal name complicates the description. In order to avoid this, in the following description, the raw material will be simply abbreviated as Sr raw material or Sr gas. And
[0080]
The Sr gas supply system 35 mainly includes an Sr raw material container 37, a liquid flow control device 38 for Sr, an Sr vaporizer 39, and the like. The vaporization temperature is about 200 ° C. The Sr gas vaporized by the Sr vaporizer 39 is mixed with Ar gas as a carrier gas, passes through an Sr gas pipe 40 heated to about 250 ° C., and passes through a quartz Sr gas injector (source gas supply jig). (Sr-Mo gas injector) 41. The Sr gas injector 41 is provided in the reaction vessel 11, and the Sr gas is supplied into the reaction vessel 11 via the Sr gas injector 41. In the vicinity of the connection between the Sr gas pipe 40 and the Sr gas injector 41, that is, at the root of the Sr gas injector 41, the gas passing through the Sr gas injector 41 is supplied with Sr gas, Ar gas or O 2 gas. ₂ A source gas supply system switching valve 12a is provided so that it can be selectively switched to gas.
[0081]
The TTIP gas supply system 36 mainly includes a TTIP container 42, a TTIP heating device 43 for heating the TTIP container 42 to about 60 ° C., and a TTIP gas flow control device 44. The TTIP gas is sent through a TTIP gas pipe 45 heated to about 100 ° C. to a TTIP gas injector 46 made of quartz as a source gas supply jig. The TTIP gas injector 46 is provided in the reaction vessel 11, and the TTIP gas is supplied into the reaction vessel 11 via the TTIP gas injector 46. Near the connection between the TTIP gas pipe 45 and the TTIP gas injector 46, that is, at the root of the TTIP gas injector 46, the gas passing through the TTIP gas injector 46 is supplied with the TTIP gas and the Ar gas or O gas. ₂ A source gas supply system switching valve 12b is provided so that it can be selectively switched to gas.
[0082]
H ₂ The O gas supply system 5 mainly includes H ₂ O container 13, this H ₂ H for heating the O container 13 to about 80 ° C. ₂ O heating device 14, and H ₂ It comprises a gas flow control device 15 for O gas. H ₂ O gas is H heated to about 150 ° C. ₂ After passing through the O gas pipe 16, quartz H ₂ It is sent to the O gas injector 17. H ₂ The O gas injector 17 is provided in the reaction vessel 11 and ₂ O gas is H ₂ It is supplied into the reaction vessel 11 via the O gas injector 17. H ₂ O gas pipe 16 and H ₂ Near the connection with the O gas injector 17, that is, H ₂ At the base of the O gas injector 17, H ₂ The gas passed through the O gas injector 17 is H ₂ O gas, Ar gas, or O gas ₂ An activation gas supply system switching valve 18 is provided so that the gas can be selectively switched.
[0083]
In addition to the three gas injectors 41, 46, and 17 (actually, including the Ba gas injector not shown) described above, the film forming apparatus 31 includes an Ar gas and a O ₂ O as a purge gas supply jig that can selectively supply gas ₂ A gas injector 19 is provided in the reaction vessel 11. That is, the film forming apparatus 31 includes gas injectors 41, 46, 17, and 19 of a total of four systems (actually, five systems including a Ba gas injector not shown). In the film forming apparatus 31, Ar gas and O are supplied to the three gas injectors 41, 46, 17, and 19, respectively. ₂ A purge gas supply system 20 for supplying at least one of the gases is provided. Ar gas or O ₂ The gas passes through a purge gas pipe 21 of the purge gas supply system 20 and is sent to each of the gas injectors 41, 46, 17, and 19.
[0084]
Further, the Sr gas injector 41, the TTIP gas injector 46, ₂ O gas injector 17, and O ₂ Each of the gas injectors 19 is formed as a porous gas injector, similarly to the first embodiment.
[0085]
On the other hand, as in the first embodiment, the reaction system 33 is capable of accommodating a plurality of substrates (wafers) 23 to be subjected to a film forming process at the same time and heating each of the wafers 23 substantially uniformly. A hot-wall type reaction vessel 11 provided with a vessel heating device 26, a boat 24 as a substrate support capable of supporting each wafer 23 in the reaction vessel 11 with their surfaces separated from each other by a predetermined distance, An exhaust system 25 for exhausting the source gas, the activation gas, and the purge gas supplied into the container 11 to the outside of the reaction container 11 is provided.
[0086]
Next, a film forming method of the present embodiment will be described with reference to FIG. Specifically, the film forming method of the present embodiment is to form the STO film 47 as a compound film by using the film forming apparatus 31 in the following sequence.
[0087]
A plurality of wafers 23 are introduced into the reaction vessel 11 and supported by a boat 24 disposed in the reaction vessel 11. Subsequently, using the container heating device 26, the atmosphere in the reaction container 11 and the temperature of each wafer 23 are substantially uniformly heated so as to be about 300 ° C. At the same time, the Sr gas injector 41, TTIP gas injector 46, O ₂ Gas injector 19 and H ₂ About 1 SLM of Ar gas is supplied into the reaction vessel 11 from the O gas injector 17 respectively, and the pressure in the reaction vessel 11 is maintained at about 1.5 Torr. After confirming that the temperature inside the reaction vessel 11 (furnace temperature) was stable at about 300 ° C. ± 10 ° C., while maintaining the pressure inside the vessel at about 1.5 Torr, based on the sequence shown in FIG. Is performed.
[0088]
First, in the reaction vessel 11, H ₂ O gas injector 17 to H ₂ About 500 sccm of O gas is introduced for about 20 seconds, and the Sr gas injector 41, the TTIP gas injector 46, and the O ₂ O from the gas injector 19 ₂ The gas is supplied at about 500 sccm for about 20 seconds each. H introduced into the reaction vessel 11 ₂ O gas is adsorbed on the surface of each wafer 23.
[0089]
Next, H ₂ O gas injector 17, TTIP gas injector 46, and O ₂ The gas supplied from the gas injector 19 is switched to Ar gas. At the same time, the gas supplied from the Sr gas injector 41 is switched to Sr gas, and the Sr source gas is introduced into the reaction vessel 11 from the Sr gas injector 41 for about 10 seconds under the condition that the THF solution flow rate is about 3 sccm. The flow rate of Ar gas as a carrier gas is about 250 sccm. At this time, the internal pressure of the Sr gas injector 41 was about 35 Torr. In addition, the TTIP gas injector 46, O ₂ Gas injector 19 and H ₂ Ar gas is supplied from the O gas injector 17 into the reaction vessel 11 at a rate of about 500 sccm for about 10 seconds.
[0090]
Usually, the decomposition reaction of the Sr raw material hardly occurs at about 280 ° C., but H ₂ Since O is adsorbed, the Sr raw material reaching the surface of each wafer 23 is adsorbed H ₂ A hydrolysis reaction occurs with O. Thus, an Sr oxide film (not shown) is formed on the surface of each wafer 23.
[0091]
Next, H is again stored in the reaction vessel 11. ₂ O gas injector 17 to H ₂ About 500 sccm of O gas is introduced for about 20 seconds, and the Sr gas injector 41, the TTIP gas injector 46, and the O ₂ O from the gas injector 19 ₂ The gas is supplied at about 500 sccm for about 20 seconds each. As a result, carbon impurities in the Sr oxide film formed on the surface of each wafer 23 are reduced, and the introduced H ₂ O gas is adsorbed on the surface of the Sr oxide film.
[0092]
H described above ₂ By alternately repeating the supply of the O gas and the supply of the Sr gas four times, an Sr oxide film having a thickness of about 0.3 nm is formed substantially uniformly on the surface of each wafer 23 in about 120 seconds. be able to.
[0093]
Next, H ₂ The gas supplied from the O gas injector 17 is H ₂ Switch to O gas and add H ₂ About 500 sccm of O gas is introduced for about 20 seconds. At the same time, the Sr gas injector 41, TTIP gas injector 46, and O ₂ The gas supplied from the gas injector 19 is O ₂ Switch to gas, O ₂ The gas is supplied into the reaction vessel 11 at a rate of about 500 sccm for about 20 seconds each.
[0094]
Next, the gas supplied from the TTIP gas injector 46 is switched to TTIP gas, and TTIP gas is introduced into the reaction vessel 11 for about 10 seconds at about 150 sccm. At the same time, H ₂ O gas injector 17, Sr gas injector 41, and O ₂ The gas supplied from the gas injector 19 is switched to Ar gas, and the Ar gas is supplied into the reaction vessel 11 at about 500 sccm for about 10 seconds each.
[0095]
Normally, under the condition that oxygen does not exist at about 280 ° C., TTIP decomposition reaction hardly occurs, but the surface of the Sr oxide film formed on the surface of each wafer 23 has H ₂ Since O is adsorbed, the ethoxy group of the TTIP gas that has reached the surface of the Sr oxide film is adsorbed by H ₂ A hydrolysis reaction occurs with O. Thus, a Ti oxide film (not shown) is formed on the surface of each wafer 23, and further reacts with the Sr oxide film.
[0096]
Next, H is again stored in the reaction vessel 11. ₂ O gas injector 17 to H ₂ About 500 sccm of O gas is introduced for about 20 seconds, and the Sr gas injector 41, the TTIP gas injector 46, and the O ₂ O from the gas injector 19 ₂ The gas is supplied at about 500 sccm for about 20 seconds each. Then, O ₂ As a result, carbon impurities in the Ti oxide film are reduced, and the introduced H ₂ O gas is adsorbed on the surface of the Ti—Sr oxide film.
[0097]
H described above ₂ The supply of the O gas and the supply of the TTIP gas are alternately repeated three times. Thereby, the molar ratio between Ti and Sr contained in the Ti—Sr oxide film deposited on the surface of each wafer 23 becomes substantially equal, and the perovskite crystal structure (SrTiO 2) ₃ ) Can be formed on the surface of each wafer 23 with a substantially uniform film thickness of about 0.4 nm in about 90 seconds.
[0098]
That is, as described above, H ₂ After a series of sequences in which the supply of O gas and the supply of Sr gas are alternately repeated four times each, ₂ By performing a series of sequences in which the supply of the O gas and the supply of the TTIP gas are alternately repeated three times, the STO film 47 having a thickness of about 0.4 nm is formed on the surface of each wafer 23 in about 210 seconds in total. A uniform film can be formed. A sequence of about 210 seconds in total consisting of these two types is defined as one cycle, and this cycle is repeated 30 times to deposit about 12 nm of the STO film 47 on the surface of each wafer 23. Then N ₂ By introducing a gas into the reaction vessel 11 and subjecting the STO film 47 to a heat treatment at about 400 ° C., the film forming process of this embodiment is completed.
[0099]
Next, as shown in FIG. 7, an STO film is formed inside and around the hole 48 having an opening diameter W of about 70 nm, a depth D of about 420 nm, and an aspect ratio of about 6. At this time, the STO film is formed based on each of the film forming method of the present embodiment and the normal thermal CVD method. Then, the uniformity of the film thickness and film composition of the STO film 47 according to the present embodiment and the STO film (not shown) formed by the normal thermal CVD method are evaluated at five points (1) to (5) in FIG. . Table 1 shows the results of this evaluation. The film thickness was evaluated by a cross-sectional TEM, and the film composition was evaluated by a TEM-EDX.
[0100]
The conditions for implementing the thermal CVD method are as follows.
[0101]
The film forming temperature is set to about 400 ° C. and the film forming pressure is set to about 1 Torr. At the same time, Sr (METHD) as raw material ₂ , And Ti (MPD) (THD) ₂ Is set so that the total raw material flow rate is about 0.3 sccm. About 50% / 50% O ₂ And N ₂ A mixed gas with O is used. Under these conditions, an amorphous STO film is formed by a thermal CVD method, and then the NTO is formed on the STO film. ₂ And RTA (Rapid Thermal Anneal) at about 650 ° C. for crystallization. The conditions for performing this thermal CVD method are such that a substantially uniform film thickness and composition ratio can be obtained in a contact hole (not shown) having a diameter of about 150 nm.
[0102]
[Table 1]

[0103]
From Table 1, it can be seen that the conventional thermal CVD method can maintain the uniformity of the film thickness of the STO film, but the uniformity of the film composition in the thin and deep hole having a large aspect ratio like the hole 48 can be maintained. Can not be held. According to Table 1, at the bottom of the hole 48, almost only a Ti oxide film is formed. That is, in the conventional thermal CVD method, it is easily expected that it is very difficult to follow LSI miniaturization for present and future.
[0104]
The electrical characteristics of the STO film 47 formed based on the present embodiment and the STO film formed based on the conventional thermal CVD method on the planar Ru electrode of a capacitor (not shown) are shown. Table 2 shows the results of the evaluation. According to Table 2, the STO film 47 formed according to the present embodiment has a higher relative dielectric constant and a lower leakage current than the STO film formed according to the conventional thermal CVD method. Indicates the value. This is considered to be because the ALD film forming method of the present embodiment is more suitable for forming a compound film having better crystallinity than the conventional thermal CVD method.
[0105]
[Table 2]

[0106]
The maximum value of the film forming temperature in the film forming process of the present embodiment is about 400 ° C. This is because a capacitor formed by using the present process is formed, for example, on an aluminum multilayer wiring (not shown) that is sensitive to heat. Indicates that is possible. This means that pollution control becomes easier when manufacturing the capacitor, and furthermore, the semiconductor device including the capacitor. Further, for example, even if a capacitor is mixedly mounted in an arbitrary layer in an LSI having a multilayer wiring structure, there is a problem such as an increase in the aspect ratio of a contact hole between wirings in layers below the capacitor and, in turn, almost all wirings in the LSI. This has the advantage of not inviting
[0107]
As described above, in the second embodiment, the same effects as those in the first embodiment can be obtained. By using a cyclopentadienyl compound as the Sr raw material and using an alkoxide or a DPM complex containing an alkoxide as the Ti raw material, H ₂ Ligands can be removed at once by hydrolysis reaction with O, and crystallization at low temperature becomes easy. For example, in the case of an STO film, crystallization at about 300 ° C. is possible. Furthermore, the Sr raw material gas and Ti raw material gas are each independently oxygen (O ₂ ) And nitrous oxide (N ₂ O) hardly reacts with O), so O ₂ And N ₂ O can be used. This is effective in that organic impurities in the STO film due to ligands and the like can be efficiently removed.
[0108]
As described above, the characteristics of the STO film 47 formed based on the present embodiment apply to the BST film formed based on the present embodiment in substantially the same manner.
[0109]
(Third embodiment)
Next, a third embodiment according to the present invention will be described with reference to FIGS. FIG. 8 is a diagram schematically illustrating a film forming apparatus according to the third embodiment. FIG. 9 is a diagram illustrating a sequence of a film forming method according to the third embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0110]
In the present embodiment, specifically, by performing an atomic layer deposition (ALD) method in a batch process, a film forming method and a film forming apparatus for forming a Ti—Al—N film as a compound film, The conditions for forming the Ti-Al-N film and the characteristics of the obtained Ti-Al-N film will be described.
[0111]
In the film forming process of the present embodiment, titanium chloride (TiCl ₄ ), And aluminum chloride (AlCl ₃ ) Are used. Also, NH as an activating gas ₃ Use gas. Further, an argon (Ar) gas is used as a purge gas.
[0112]
First, the film forming apparatus 51 of the present embodiment will be described with reference to FIGS.
[0113]
FIG. 8A is a diagram showing a schematic configuration of the film forming apparatus 51 viewed from the front or side. FIG. 8B is a plan view showing the film forming apparatus 51 viewed from the direction of the solid arrow in FIG. The film forming apparatus 51 mainly includes a source gas supply system 52 and a reaction system 53, as in the first and second embodiments described above. The source gas supply system 52 is made of TiCl ₄ Gas supply system 54, AlCl ₃ Gas supply system 55 and NH ₃ It comprises a gas supply system 56 and the like.
[0114]
TiCl ₄ The gas supply system 54 is mainly composed of TiCl ₄ Gas cylinder 56, TiCl for heating this cylinder 56 ₄ Heating device 57 and high temperature specification TiCl ₄ It comprises a gas flow control device 58 and the like. Similarly, AlCl ₃ The gas supply system 55 mainly includes AlCl ₃ Gas cylinder 59, AlCl for heating this cylinder 59 ₃ Heating device 60 and high temperature specification AlCl ₃ It comprises a gas flow control device 61 and the like. TiCl ₄ Gas cylinder 56 and AlCl ₃ The temperature of the gas cylinders 59 is about 60 ° C. respectively. TiCl ₄ Gas and AlCl ₃ The gases were TiCl, each heated to about 80 ° C. ₄ Gas piping 62 and AlCl ₃ Passing through the gas pipe 63, the quartz-made TiCl as a source gas supply jig ₄ Gas injector 64 and AlCl ₃ The gas is sent to the gas injector 65 independently of each other. TiCl ₄ Gas injector 64 and AlCl ₃ The gas injectors 65 are provided in the reaction vessel 11 independently of each other, and ₄ Gas and AlCl ₃ Each gas is TiCl ₄ Gas injector 64 and AlCl ₃ The gas is supplied into the reaction vessel 11 via the gas injector 65.
[0115]
TiCl ₄ Gas pipe 62 and TiCl ₄ Near the connection with the gas injector 64, that is, TiCl ₄ At the base of the gas injector 64, TiCl ₄ The gas passed through the gas injector 64 is TiCl ₄ A source gas supply system switching valve 12c is provided so that the gas or Ar gas can be selectively switched. Similarly, AlCl ₃ Gas piping 63 and AlCl ₃ Near the connection with the gas injector 65, ie, AlCl ₃ At the base of the gas injector 65, AlCl ₃ The gas passed through the gas injector 65 is AlCl ₃ A source gas supply system switching valve 12d is provided so that the gas or Ar gas can be selectively switched.
[0116]
H ₂ The O gas supply system 56 mainly includes NH ₃ Gas cylinder 66 and NH ₃ It comprises a gas flow controller 67 for gas. NH ₃ The gas was NH heated to about 60 ° C. ₃ Quartz NH as an activating gas supply jig passing through the gas pipe 68 ₃ The gas is sent to the gas injector 69. NH ₃ The gas injector 69 is provided in the reaction vessel 11 and is provided with NH 3 ₃ Gas is NH ₃ The gas is supplied into the reaction vessel 11 via the gas injector 69. NH ₃ Gas piping 68 and NH ₃ Near the connection with the gas injector 69, ie, NH ₃ At the base of the gas injector 69, NH ₃ The gas passed through the gas injector 69 is NH ₃ An activation gas supply system switching valve 18a is provided so that it can be selectively switched to gas or Ar gas.
[0117]
As described above, the film forming apparatus 31 includes the three gas injectors 64, 65, and 69. Also, TiCl ₄ Gas injector 64, AlCl ₃ Gas injector 65 and NH ₃ The gas injector 69 is formed as a porous gas injector similarly to the first and second embodiments.
[0118]
On the other hand, as in the first and second embodiments, the reaction system 53 can simultaneously accommodate a plurality of substrates (wafers) 23 on which a film forming process is to be performed, and can roughly store the respective wafers 23. A hot-wall type reaction vessel 11 provided with a vessel heating device 26 so as to be able to heat uniformly, and as a substrate support capable of supporting each wafer 23 in the reaction vessel 11 with their surfaces separated from each other by a predetermined distance. And an exhaust system 25 for exhausting the raw material gas, the activation gas, and the purge gas supplied into the reaction vessel 11 to the outside of the reaction vessel 11. At the same time, ClF for cleaning the inside of the reaction vessel (chamber) 11 ₃ ClF for supplying gas into the reaction vessel 11 ₃ A gas supply system 70 is provided.
[0119]
As shown in FIGS. 8 (a) and 8 (b), the reaction container 11 of the present embodiment has three gas injectors 64, 65, with each wafer 23 accommodated therein being interposed therebetween. A plurality of slit-shaped exhaust holes 71 for exhausting unnecessary gas in the reaction vessel 11 to the outside of the reaction vessel 11 are provided on the side (position) opposite to 69 in accordance with the number of wafers 23. I have. At the same time, the boat 24 is provided with a shielding plate (rectifying plate) 72 as a rectifying member that surrounds each wafer 23 from both sides thereof from near each exhaust hole 71 to near three gas injectors 64, 65, and 69. Have been. As a result, each gas supplied to the reaction vessel 11 through the three gas injectors 64, 65, and 69 hardly flows out of the shielding plate 72, and intensively wraps each wafer 23 supported by the boat 24. As described above, the gas flows from the outlets 27 of the gas injectors 64, 65, 69 toward the exhaust holes 71.
[0120]
By adopting such a structure, firstly, it is possible to suppress the deposition (adhesion) of the metal film on the inner wall itself of the reaction vessel 11 and to precisely control the temperature of each wafer 23. . Generally, the more the metal film covering the inner wall of the reaction vessel 11, the more difficult it is for radiant heat from an external heat source such as the vessel heating device 26 to reach each wafer 23. However, in the reaction vessel 11 of the present embodiment, since the metal film can be prevented from being deposited on the inner wall of the reaction vessel 11 by the above-described structure, the container heating device 26 can be used to remove each wafer 23 contained in the reaction vessel 11. The temperature can be precisely controlled. Second, with the above-described structure, the source gas, the activation gas, and the purge gas flow around each wafer 23 while substantially confining the gas, such as near the surface of each wafer 23 or between the wafers 23. be able to. Thereby, the reaction rate of the film forming reaction can be increased, and the utilization efficiency of each gas can be further improved. Further, there is an advantage that the purging inside the reaction vessel 11, particularly around each wafer 23, can be performed easily and quickly.
[0121]
Further, when the film process is repeated a plurality of times, ClF is placed in the reaction vessel 11 between each process. ₃ By supplying the gas, the inside of the reaction ₃ Can be cleaned. This makes it possible to substantially completely remove the metal film deposited on the inner wall of the reaction vessel 11 before performing the film forming process. Thus, according to the film forming apparatus 51 of the present embodiment, the compound film can be formed in a more appropriate state.
[0122]
Next, a film forming method according to the present embodiment will be described with reference to FIG. Specifically, the film forming method according to the present embodiment uses a film forming apparatus 51 to form a Ti film (not shown) as a compound film in the following sequence. _0.7 Al _0.3 This is for forming an N film.
[0123]
The plurality of wafers 23 on which the film forming process is performed include Ti _0.7 Al _0.3 A contact hole (not shown) having an opening diameter of about 130 nm in which the N film is embedded is formed in advance. Then, on the surface of each wafer 23, a Ti film (not shown) of about 10 nm is previously formed by long throw sputtering (LTS) in order to reduce the contact resistance. At the same time, silicidation of each wafer 23 is completed by RTA at about 600 ° C.
[0124]
A plurality of wafers 23 which have been subjected to the processing described above are introduced into the reaction vessel 11 and supported by the boat 24 arranged in the reaction vessel 11. Subsequently, using the container heating device 26, the atmosphere in the reaction container 11 and the temperature of each wafer 23 are substantially uniformly heated so that the temperature of each wafer 23 becomes about 500 ° C. At the same time, TiCl ₄ Gas injector 64, AlCl ₃ Gas injector 65 and NH ₃ About 1 SLM of Ar gas is supplied into the reaction vessel 11 from the gas injector 69, and the pressure in the reaction vessel 11 is maintained at about 1.0 Torr. After confirming that the temperature inside the reaction vessel 11 (furnace temperature) was stable at about 500 ° C. ± 20 ° C., while maintaining the pressure inside the vessel at about 1.0 Torr, based on the sequence shown in FIG. Is performed.
[0125]
First, NH 3 is introduced into the reaction vessel 11. ₃ NH from gas injector 69 ₃ A gas is introduced for about 1 SLM for about 10 seconds and TiCl ₄ Gas injector 64 and AlCl ₃ Ar gas is supplied from the gas injector 65 at about 500 sccm for about 10 seconds. NH introduced into the reaction vessel 11 ₃ The gas is adsorbed on the surface of each wafer 23.
[0126]
Next, AlCl ₃ While supplying Ar gas from the gas injector 65 into the reaction vessel 11, ₃ The gas supplied from the gas injector 69 is switched to Ar gas. At the same time, TiCl ₄ The gas supplied from the gas injector 64 is TiCl ₄ The gas was switched to TiCl in the reaction vessel 11. ₄ The gas is introduced for about 1 SLM for about 5 seconds. AlCl ₃ Gas injector 65 and NH ₃ Ar gas is supplied from the gas injector 69 into the reaction vessel 11 at about 500 sccm for about 5 seconds.
[0127]
Usually, at around 500 ° C, TiCl ₄ Decomposition reaction hardly occurs, but the surface of each wafer 23 ₃ Are adsorbed, so that TiCl reaching the surface of each wafer 23 ₄ The gas is adsorbed NH ₃ Causes a decomposition reaction between Thus, a Ti nitride film (not shown) is formed on the surface of each wafer 23.
[0128]
Next, NH 3 is again introduced into the reaction vessel 11. ₃ NH from gas injector 69 ₃ A gas is introduced for about 1 SLM for about 10 seconds and TiCl ₄ Gas injector 64 and AlCl ₃ Ar gas is supplied from the gas injector 65 at about 1 SLM for about 10 seconds. Thereby, the Ti deposited on the surface of each wafer 23 is almost completely nitrided, and the chlorine in the Ti raw material remaining in the Ti nitride film is released as ammonium chloride. Furthermore, the introduced NH ₃ The gas is adsorbed on the surface of the Ti nitride film.
[0129]
NH explained above ₃ Gas supply and TiCl ₄ The supply of gas is repeated alternately five times over about 75 seconds.
[0130]
Next, NH ₃ The gas supplied from the gas injector 69 is NH ₃ Switch to gas and place NH in the reaction vessel 11 ₃ The gas is introduced for about 1 SLM for about 10 seconds. Also, AlCl ₃ While supplying Ar gas into the reaction vessel 11 from the gas injector 65, TiCl ₄ The gas supplied from the gas injector 64 is switched to Ar gas. AlCl ₃ Gas injector 65 and TiCl ₄ Ar gas is supplied into the reaction vessel 11 from the gas injector 64 by about 1 SLM for about 10 seconds each.
[0131]
Next, TiCl ₄ While supplying Ar gas from the gas injector 64 into the reaction vessel 11, ₃ The gas supplied from the gas injector 65 is AlCl ₃ Switch to gas. At the same time, NH ₃ The gas supplied from the gas injector 69 is switched to Ar gas. AlCl ₃ From the gas injector 65, the AlCl ₃ The gas is supplied for about 1 SLM for about 5 seconds. Also, TiCl ₄ Gas injector 64 and NH ₃ Ar gas is supplied into the reaction vessel 11 from the gas injector 69 at a rate of about 1 SLM for about 5 seconds.
[0132]
Usually, at around 500 ° C., AlCl ₃ Decomposition reaction hardly occurs, but the surface of the Ti nitride film formed on the surface of each wafer 23 ₃ Is adsorbed, so that AlCl reaches the surface of the Ti nitride film. ₃ The gas is adsorbed NH ₃ And cause a hydrolysis reaction. Thus, an Al nitride film (not shown) is formed on the surface of each wafer 23.
[0133]
Next, NH 3 is again introduced into the reaction vessel 11. ₃ NH from gas injector 69 ₃ A gas is introduced for about 1 SLM for about 10 seconds and TiCl ₄ Gas injector 64 and AlCl ₃ Ar gas is supplied from the gas injector 65 at about 1 SLM for about 10 seconds. As a result, Al deposited on the surface of each wafer 23 is almost completely nitrided, and chlorine in the Al raw material remaining in the Al nitride film is released as ammonium chloride. Furthermore, the introduced NH ₃ The gas is adsorbed on the surface of the Al nitride film.
[0134]
NH explained above ₃ Gas supply and AlCl ₃ The supply of gas is repeated twice alternately. This allows the Ti over the surface of each wafer 23 in about 30 seconds. _0.7 Al _0.3 A compound film having a composition of N can be formed with a substantially uniform thickness of about 2.5 nm.
[0135]
That is, as described above, NH 3 ₃ Gas supply and TiCl ₄ After a series of sequences of alternately repeating the supply of gas five times, NH 3 ₃ Gas supply and AlCl ₃ By performing a series of sequences in which gas supply is alternately repeated twice each time, a Ti film having a thickness of about 2.5 nm is formed on the surface of each wafer 23 in about 105 seconds in total. _0.7 Al _0.3 The N film can be formed substantially uniformly. A sequence of about 105 seconds in total consisting of these two types is defined as one cycle, and this cycle is repeated 30 times to deposit a Ti-Al-N film on the surface of each wafer 23 to a thickness of about 75 nm. Thus, the film forming process of the present embodiment is completed.
[0136]
According to the present inventors, it has been confirmed that the contact holes formed in advance in each wafer 23 can be almost completely filled with almost no voids or the like by the film forming process described above. Also, the surface of the contact plug (not shown) formed using these contact holes was hardly oxidized even by heat treatment in an oxidizing atmosphere at about 540 ° C., and it was confirmed that the contact resistance was sufficiently low.
[0137]
As described above, in the third embodiment, the same effects as those in the first embodiment can be obtained. Further, as described above, a plurality of exhaust holes 11 are provided on the side of the reaction vessel 11 opposite to the side on which the gas injectors 64, 65, 69 are provided, with each wafer 23 interposed therebetween. This allows the source gas, the activation gas, and the purge gas to flow while controlling their flows in a substantially constant direction. As a result, the use efficiency and exhaust efficiency of each gas can be further increased, and the purge time can be further reduced. Such effects include a shielding effect and a rectifying effect of the shielding plate 72 attached to the boat 24 from each gas injector 64, 65, 69 to each exhaust hole 11, and each wafer 23 supported by the boat 24 while being separated from each other. It is further enhanced by synergistic effects with its own rectifying effect. The source gas, the activation gas, and the purge gas supplied toward the respective wafers 23 from the plurality of blowing holes 27 provided in the respective gas injectors 64, 65, and 69 are guided by the respective wafers 23 and the shielding plate 72. It flows so as to wrap each wafer 23 toward each exhaust hole 11. Therefore, according to the third embodiment, a high-quality compound film can be formed very efficiently and very easily.
[0138]
Note that the film forming method, the film forming apparatus, and the method for manufacturing a semiconductor device according to the present invention are not limited to the above-described first to third embodiments. The present invention can be implemented by changing a part of the configuration, the process, or the like to various various settings, or using the various settings as appropriate, without departing from the spirit of the present invention.
[0139]
For example, the film forming apparatus 1 of the first embodiment can be made of TiO 2 by using tetraisopropoxide titanium (TTIP) as a raw material without changing the apparatus configuration. ₂ It is also possible to form a film or a Ta-Ti-O film. Similarly, as a raw material, AlCl ₃ By using, Al ₂ O ₃ It is also possible to form a film.
[0140]
In each of the first to third embodiments, the wafers 23 are arranged in the reaction vessel 11 so as to be vertically stacked with their surfaces (substrate surfaces) separated from each other. However, the arrangement state of each wafer 23 is not limited to this. For example, the wafers 23 may be arranged in the reaction vessel 11 so as to be arranged in the left-right (lateral) direction with their surfaces (substrate surfaces) separated from each other. Further, each of the wafers 23 does not need to be arranged in a posture parallel to each other. At the same time, each of the wafers 23 does not need to be arranged such that the intervals between the adjacent wafers 23 are all set to a uniform size. The arrangement direction, posture, interval, and the like of each wafer 23 are determined according to the type, weight, properties, flow direction, and the order in which each gas is supplied to each wafer 23. May be appropriately set so that the compound film is formed almost uniformly and in an appropriate state on the surface. In this case, it is preferable that the boat 24 be configured so that the arrangement direction, posture, interval, and the like of each wafer 23 can be appropriately set to an appropriate state.
[0141]
Further, it is not necessary to uniformly set the supply pressure, the blowout amount, and the like of each gas supplied from the raw material gas injector, the activation gas injector, and the purge gas injector. A compound film is formed on the surface of each wafer 23 in a substantially uniform and appropriate state according to the type, weight, property, flow direction, and order of supply of each gas of each gas. As described above, an appropriate state may be set for each gas injector. Further, the gas supply pressure and the amount of gas blown out from the plurality of blowout holes 27 provided in each gas injector are set to appropriate sizes according to the position of each hole 27, that is, the arrangement position of each wafer 23. You can do it. For example, when the wafers 23 are arranged so as to be vertically stacked as in the first to third embodiments, the gas supply pressure and the blowout amount from the blowout holes 27 are adjusted from the uppermost wafer 23 to the lowest. An appropriate size may be set for each height of each hole 27 so that each gas is supplied substantially evenly to the lower wafer 23. Thereby, a compound film can be formed more uniformly and more appropriately on the surface of each wafer 23.
[0142]
Further, in the third embodiment, the shielding plates (rectifying plates) 72 are provided on both sides of each wafer 23, but the invention is not limited to this. For example, the shielding plate 72 may be provided from the gas injectors to the exhaust holes 71 and above the boat 24 supporting the wafers 23. As a result, the shielding effect and the rectifying effect of each gas supplied to each wafer 23 can be further improved, and the utilization efficiency of each gas and eventually the film formation efficiency can be greatly improved. Alternatively, the upper and lower ends of the boat 24 supporting each wafer 23 may be formed in a shape capable of exhibiting a shielding effect and a rectifying effect. Thereby, even when the boat 24 is not provided with the shielding plate 72 as in the first and second embodiments, the utilization efficiency of each gas and the film formation efficiency can be improved. Further, if the boat 24 having such a shape is used together with the shielding plate 72, it goes without saying that the utilization efficiency of each gas and the film formation efficiency can be extremely improved.
[0143]
In addition, while each gas is being supplied from each gas injector, it is preferable that unnecessary gas in the reaction vessel 11 is positively exhausted to the outside of the reaction vessel 11 by the exhaust system 25. Thus, even when a plurality of types of gases are used, unnecessary gas-phase reactions can be significantly reduced, and a higher quality compound film can be formed.
[0144]
Further, semiconductor devices that can be manufactured using the film forming method, the film forming apparatus, and the method for manufacturing a semiconductor device according to the present invention are not limited to semiconductor devices that are currently widely used, such as DRAM. The method for manufacturing a semiconductor device according to the present invention can of course be sufficiently applied to manufacture various fine semiconductor devices, such as FeRAM, which are expected to develop in the future.
[0145]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the film-forming method and film-forming apparatus which concern on this invention, since purging in a process chamber can be performed easily in a short time, prolongation of a film-forming operation | work can be easily suppressed and gas use efficiency can be made easy. And the mutual reaction between a plurality of types of gases can be easily suppressed. Therefore, according to the film forming method of the present invention, a high-quality compound film can be efficiently and easily formed when performing a film forming operation by batch processing using the ALD method.
[0146]
Further, according to the method for manufacturing a semiconductor device according to the present invention, by using a compound film formed by the film forming method according to the present invention, various fine semiconductor elements incorporated inside the semiconductor device can be improved. The semiconductor device can be formed efficiently and easily with high quality, and the quality and yield of the semiconductor device can be easily improved. Therefore, according to the method of manufacturing a semiconductor device according to the present invention, a high-quality semiconductor device having a high-quality compound film can be efficiently and easily manufactured.
[Brief description of the drawings]
FIG. 1 is a view schematically showing a film forming apparatus according to a first embodiment.
FIG. 2 is a view showing a sequence of a film forming method according to the first embodiment.
FIG. 3 shows Ta on a substrate ₂ O ₅ FIG. 4 is a process cross-sectional view schematically illustrating a mechanism in which a film is formed.
FIG. 4 is Ta ₂ O ₅ FIG. 4 is a graph showing the dependence of particles generated when forming a film on a film forming cycle.
FIG. 5 is a diagram schematically illustrating a film forming apparatus according to a second embodiment.
FIG. 6 is a view showing a sequence of a film forming method according to a second embodiment.
FIG. 7 is a cross-sectional view schematically showing an STO film formed inside and around a hole by a film forming method according to a second embodiment.
FIG. 8 is a diagram schematically illustrating a film forming apparatus according to a third embodiment.
FIG. 9 is a view showing a sequence of a film forming method according to a third embodiment.
FIG. 10 is a simplified perspective view showing a film forming apparatus according to a conventional technique.
FIG. 11 is a view showing a sequence of a film forming method according to a conventional technique.
FIG. 12 is a simplified perspective view showing another film forming apparatus according to the related art.
[Explanation of symbols]
1, 31, 51 ... film forming equipment
2, 32, 52 ... source gas supply system
5, 56 ... activated gas supply system
10 PET gas injector (source gas supply jig)
11 ... reaction vessel (processing chamber)
17 ... H ₂ O gas injector (activation gas supply jig)
19 ... O ₂ Gas injector (purge gas supply jig)
20 ... Purge gas supply system
23 ... Wafer (substrate to be processed)
24 ... Boat (substrate support)
27… Blowout hole
28 ... Ta ₂ O ₂ Film (compound film)
41 Sr gas injector (source gas supply jig)
46 TTIP gas injector (source gas supply jig)
47 ... SrTiO ₃ Film (compound film)
64 ... TiCl ₄ Gas injector (source gas supply jig)
65 ... AlCl ₃ Gas injector (source gas supply jig)
69… NH ₃ Gas injector (activation gas supply jig)
71 ... exhaust hole
72 ... Shielding plate (rectifying plate, rectifying member)

Claims (6)

A film forming method for collectively forming a compound film on the surface of a plurality of substrates to be processed at an atomic layer level,
A first step of arranging the respective substrates to be separated from each other and parallel to each other along a thickness direction in a reaction vessel in which the film forming process is performed;
Activating gas supply for supplying an activating gas for activating a film forming reaction among a plurality of gas supply jigs for supplying a predetermined gas into the reaction vessel toward between the adjacent substrates to be processed. A second step of supplying the activation gas from a jig and supplying a purge gas from another gas supply jig;
A third step of switching the gas supplied from the activation gas supply jig from the activation gas to the purge gas and supplying the purge gas from another gas supply jig;
The source gas is supplied from a source gas supply jig that supplies a source gas serving as a main source of a compound film to be formed into a film between the adjacent target substrates, and from another gas supply jig. A fourth step of supplying the purge gas;
A fifth step of switching the gas supplied from the source gas supply jig from the source gas to the purge gas and supplying the purge gas from another gas supply jig;
And repeating the second to fifth steps a plurality of times. A film forming method for collectively forming a compound film on surfaces of a plurality of substrates to be processed,
Each of the substrates to be processed is spaced apart from each other and arranged along the thickness direction,
An activation gas for activating a film formation reaction is continuously supplied with a purge gas from each of the substrates to be processed in a direction substantially parallel to the substrate surface. A film forming method characterized by alternately supplying a raw material gas serving as a raw material. In a processing chamber in which a film forming process for forming a compound film on the surfaces of a plurality of substrates to be formed collectively is performed, the respective substrates to be processed are separated along the thickness direction by separating their surfaces from each other. Place them side by side,
After purging the processing chamber by supplying a purge gas into the processing chamber where each of the substrates to be processed is disposed,
For each of the substrates to be processed disposed in the purged processing chamber, the purge gas is continuously supplied from a direction substantially parallel to the surfaces of the substrates, and an activation gas for activating a film forming reaction is supplied. Supplying on the surface of each of the substrates to be processed,
While supplying the purge gas toward each of the substrates to be processed, the supply of the activation gas is cut off, and the main surface of the compound film is directed toward each of the substrates to be processed from a direction substantially parallel to their substrate surfaces. Forming a film of the compound on the surface of each of the substrates to be processed by supplying a source gas serving as a raw material onto the surface of each of the substrates to be processed. A processing chamber provided for a film forming process;
In the processing chamber, a plurality of substrates to be processed on which the film forming process is performed are separated from each other, and a substrate support that can be arranged and supported along the thickness direction;
A source gas serving as a main source of a compound film formed on the surface of each of the substrates to be collectively formed, and a purge gas for purging the processing chamber are directed toward each of the substrates to be processed. A source gas supply jig for supplying from a direction substantially parallel to the substrate surface,
A source gas supply system that supplies the source gas to the source gas supply jig;
An activating gas for activating a film forming reaction when the compound film is formed, and an activating gas for supplying the purge gas toward each of the substrates to be processed from a direction substantially parallel to their substrate surfaces. A supply jig,
An activation gas supply system that supplies the activation gas to the activation gas supply jig;
A purge gas supply system that selectively switches the purge gas between the source gas and the activation gas and supplies the source gas and the activation gas supply jig to the source gas supply jig and the activation gas supply jig;
A film forming apparatus comprising: The source gas supply jig and the source gas supply system are independently provided for each type of the source gas, and the source gas supply system independently supplies the source gas for each type of the source gas. The film forming apparatus according to claim 4, wherein the apparatus is set so as to be able to be supplied to a supply jig. A method for manufacturing a semiconductor device, comprising: forming a semiconductor element using a compound film formed by the film forming method according to claim 1.

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