201124552 六、發明說明： 【發明所屬之技術領域】 本發明’係有關於鈷膜之形成方法。 【先前技術】 在現今之Cu配線膜形成製程中，係將PVD-阻障膜（ 例如PVD-Ti膜或者是Ta膜）和PVD-種晶膜（PVD-Cu 膜）以一貫真空（in-situ)來形成，之後，進行Cu電鍍 工程、C Μ P工程。但是’由於近年之配線的細微化，在 裝置節點3 2 n m世代之後’ Ρ V D膜之晶圓邊緣的非對稱性 或者是懸垂（〇 v e r h a n g )係變得顯著，並有著在電鍍工程 中而產生空洞（V 〇 i d )的問題。 於此，所謂P V D -阻障膜’係指藉由p v 〇法所形成之 阻障膜，所謂p V D -種晶膜，係指藉由p V D法所形成之種 日日膜。以下所記載之P V D ( C V D ) - c u膜、A L D -阻障膜、 (C V D、A L D )-鈷膜，係分別指藉由p V D、C V D ' A L D 所形成之各膜。 例如，如同圖1 ( a )以及（b )中所示一般，若是在 被形成於設置有4 32nm之孔或者是溝渠的基板丨〇】上之 阻障膜1 0 2之上，形成p v D -種晶膜1 〇 3 ( p v D _ c u膜）’ 則孔或者是溝渠之上部會產生懸垂（A部分）並使孔等之 開口部Μ得狹$，而當接著藉由電鍍工程來將孔等之內部 以Cu膜丨04來作塡埋時，電鍍液係會成爲難以進入至內 部，並且，Cu膜與阻障膜之間的密著性亦並不佳，故而 -5- 201124552 ，隨著Cu膜之被埋入，Cu膜係會被吸起，而有著在Cu 膜中產生空洞（B部分）的問題。又，如同圖1 ( ^ )以及 (d )中所示一般’在孔等之側面處，係無法均—地對稱 性形成P V D -種晶膜1 0 3 ( C部分），而，起因於此阻障膜 之非對稱性，在後續之電鍍工程中所被埋入了的Cu膜 1 04之中，係亦會有產生空洞（D部分）之問題。 藉由 ALD法或者是CVD法所形成之阻障膜以及 CVD-Cu膜，由於係並不會有非對稱性或者是懸垂的問題 ，因此，係嘗試有使用此2種的製程來形成Cu配線膜之 方法（例如，參考專利文獻1 )。但是，此情況下之問題 點，係在於：由於CVD-Cu膜與身爲其之基底膜的ALD-阻障膜之間的密著性係爲低，因此，會有在Cu膜中產生 空洞的情況。故而，現今係尙未被實用化。 例如，如圖2 ( a )以及（b )中所示一般，當在被設 置於基板20 1上之孔或者是溝渠內，藉由ALD法來形成 TiN阻障膜（ALD-TiN阻障膜）202，之後，將孔等之內 部藉由CVD-Cu膜203而作了塡埋的情況時，在Cu膜內 部，係會產生空洞（A部分）。圖2(a)，係爲藉由 CVD-Cu膜203而作了塡埋的狀態下之基板剖面的SEM照 片，圖2(b)，係爲其之模式圖。 爲了將如同上述一般之起因於CVD-Cu膜與身爲其之 基底膜的 ALD-阻障膜之間的密著性不佳所產生的Cu膜 中之空洞消除，並對於阻障性/密著性作改善，係開始嘗 試利用覆蓋性爲佳且在薄膜下係爲低電阻之鈷膜，而，由 -6- 201124552 c V D法或者是A L D法所進行之鈷膜之成膜技術的開發， 係成爲當務之急。針對鈷膜，不僅是在Cu配線膜之領域 中，就算是在矽化層或者是帽層之領域中，亦同樣的對於 覆蓋性高之鈷膜的要求日益提升。 相對於此，在由先前技術所進行之藉由使用有Co與 胺之有機金屬材料的CVD法所得到之鈷膜的情況時（例 如’參考專利乂獻2 ) ’ C 〇核之成長時間’係爲2 0分鐘 而爲長，又，Co核之成長速度，係爲lnm/分而爲慢，並 且，亦有著C之雜質濃度爲3 0 %而爲多等等的問題。 [先前技術文獻] [專利文獻] [專利文獻1]日本特開2003-055769號公報 [專利文獻2]日本特開2006-299407號公報 【發明內容】 [發明所欲解決之課題] 本發明之課題’係在於對上述之先前技術的問題點作 解決’其目的，係在於提供一種：使用特定之還原氣體來 藉由CVD法等而形成鈷膜之方法。 [用以解決課題之手段] 本發明之鈷膜之形成方法，係爲在作爲基底之S i基 材表面上而形成鈷膜之方法，其特徵爲：使用烷基脒基鈷 201124552 、和由 nh3、n2h4、nh(ch3)2、n2h3ch 以及 n2 擇之還原氣體或者是將h2以及前述還原氣體作了 氣體，來形成鈷膜。 如此這般，藉由作爲還原氣體，而代替先前 h2氣體或者是除了該h2氣體之外更進而使用NH3 ，而成爲能夠抑制Co之核生成時間、控制鈷膜之 度、改善表面形態（m 0 r p h ο 10 g y )、抑制雜質濃度 爲低電阻化，而使鈷膜成爲能夠利用在半導體裝置 圖案中。 在上述鈷膜之形成方法中，係具備有下述特徵 是，係爲對於如同Si基材一般之基材的表面， nh3而進行前置處理，之後，使用如同雙烷基脒基 之烷基脒基鈷、和由nh3、n2h4、nh(ch3)2、n2h 及n2中所選擇之還原氣體、h2、或者是將h2以及 原氣體作了組合之氣體，來形成鈷膜。 如此這般，藉由對於如同Si基材一般之基材 而先藉由NH3來進行前置處理，再進而使用還原 而成爲能夠抑制Co之核生成時間、控制鈷膜之成 、改善表面形態（m 〇 r p h ο 1 〇 g y )、抑制雜質濃度， 低電阻化，而使鈷膜成爲能夠利用在半導體裝置之 案中。 本發明，係具備有下述特徵：亦即是，上述烷 鈷，係爲 Co(tBu-Et-Et-amd)2。 中所選 組合之 技術之 氣體等 成長速 ，並成 之細微 :亦即 先藉由 鈷一般 3CH以 前述還 的表面 氣體， 長速度 並成爲 細微圖 基脒塞 201124552 [發明之效果] 若依據本發明，則相較於先前技術之作爲還原氣體而 僅使用Η2所形成的鈷膜，並不對於s i基材表面進行前置 處理地而將NHS等作爲還原氣體來使用所形成了的鈷膜 、以及在對於Si基材表面而藉由NH3來進行了前置處理 之後再將I以及/或者是NH3等作爲還原氣體來使用所形 成了的鈷膜，係成爲能夠抑制C 〇之核生成時間、使鈷膜 低電阻化、改善表面形態（m 〇 r p h 〇 1 0 g y )、並成爲能夠以 低溫來成膜，因此’係能夠達成下述之效果：亦即是，在 半導體裝置製作工程中’係能夠使產率提升，並且，藉由 將銘膜之使用溫度領域擴廣，而使鈷膜成爲能夠利用在細 微加工中。 進而’若依據本發明，則係能夠將鈷膜藉由c V D法 、A LD法來形成，並且’係能夠將其薄膜化，而成爲能 夠在半導體裝置中而將鈷膜利用在更多的工程中。 【實施方式】 若依據本發明之鈷膜的形成方法之實施形態，則係爲 一種在作爲基底之如同S i基材一般的基材之表面上而形 成銘膜之方法’其係使用如同雙烷基脒基鈷一般之包含有 C 0以及院基脒基（此烷基，係爲乙基、丁基）的有機金 屬材料’以及作爲用以將此有機金屬材料還原並形成鈷膜 的還原氣體之由身爲週知之還原氣體的NH3、N2H4、 N^UCH3)2、N2H3CH以及N2中所選擇之還原氣體或者是 201124552 將H2以及前述還原氣體（於該些之中，特別是以nh3爲 理想）作了組合之氣體，而能夠藉由CVD法或者是ALD 法，在成膜壓力：1〇〇〜lOOOPa、基板溫度：200〜400 °C、 還原氣體（例如：NH3 )流量：100〜lOOOsccm的條件下， 形成CVD ( ALD )-鈷膜，藉由使用此種還原氣體，係成 爲能夠抑制Co之核生成時間、控制鈷膜之成長速度、改 善表面形態（morphology )、抑制雜質濃度，並成爲低電 阻化，而使鈷膜之在細微圖案中的作爲密著層、矽化層、 帽層之利用成爲可能。 在上述之鈷膜的形成方法中，係能夠對於如同S i基 材一般的基材之表面，而在成膜壓力：1〇〇〜1000Pa、基板 溫度：200〜400°C、氣體流量：100〜lOOOsccm —般的條件 下，藉由nh3來先進行前置處理，之後，使用如同雙烷 基脒基鈷一般之包含有Co以及烷基脒基的有機金屬材料 ，以及由身爲週知之還原氣體的nh3、n2h4、nh(ch3)2 、n2h3ch以及n2中所選擇之還原氣體或h2亦或是將h2 以及前述還原氣體（於該些之中，特別是以nh3爲理想 )作了組合之氣體’而藉由CVD法或者是ALD法，來在 週知之製程條件（例如，成膜壓力：1 0 0〜1 0 0 0 P a、基板溫 度：200〜400 °C、還原氣體流量：100~1000sccm)下，形 成CVD(ALD)-鈷膜，藉由如此這般地在先對於Si基材 表面藉由NH3來進行了前置處理之後，再使用此種氣體 ’係成爲能夠抑制Co之核生成時間、控制鈷膜之成長速 度、改善表面形態（m 〇 r p h ο 1 〇 g y )、抑制雜質濃度，並成 -10- 201124552 爲低電阻化，而使鈷膜之在細微圖案中的作爲密著層、矽 化層、帽層之利用成爲可能。 作爲上述之由烷基脒基鈷所成之有機金屬材料，例如 ，係可列舉出 Co(tBu-Et-Et-amd)2 等。 [實施例1] 在本實施例中，係對於下述之2種情況下，相對於成 膜時間（分）之膜厚（nm )的關係作了檢討：在將自然 氧化物除去後的Si基材上，藉由CVD法，而在成膜壓力 :500Pa、基板溫度：300°C、還原氣體流量：20〇sccm的 條件下，作爲有機金屬材料，而使用 Co(tBu-Et-Et-amd)2 ，並作爲還原氣體，而僅使用NH3來形成了鈷膜（NH3還 原鈷膜）的情況；和藉由C V D法，而在成膜壓力：5 0 0 P a 、基板溫度：3 00 t、還原氣體流量：20〇SCCm的條件下 ’作爲有機金屬材料，而使用C〇(tBu-Et-Et-amd)2，並作 爲還原氣體，而使用H2來形成了鈷膜（H2還原鈷膜）的 情況。此膜厚，係相當於每單位時間之成膜速率。 將所得到之結果展示於圖3中。如同由圖3而能夠明 顯得知一般，在H2還原鈷膜的情況時，成膜速率係爲 1 nm/分，核生成時間係爲20分，相對於此，在NH3還原 鈷膜的情況時，成膜速率係爲8nm/分，核生成時間係爲〇 ，故能夠得知，係立即產生有核，並立即開始成膜。 可以想見，起因於將此些之NH3作爲還原氣體來使 用一事所導致的雜質量之降低而造成的鈷膜表面之平滑化 -11 - 201124552 、鈷膜之低電阻化以及鈷膜成膜速率之增大 成時間的縮短，係由於NH3自由基會促進原 藉此而使Co之分壓增大之故。故而，在本發 形成中，係能夠使用產生此種自由基之還原氣 [實施例2] 當代替在實施例1中所使用之作爲還原棄 而使用由 n2h4、nh(ch3)2、n2h3ch 以及 n2 還原氣體的情況時，以及使用將H2與由NH: 、N2H3CH以及N2中所選擇之還原氣體作了徒 情況時，在反覆進行了實施例1之製程之後， 實施例1之情況相同的，Co核之生成時間，{; ，核係立即被產生，並開始成膜。 [實施例3] 在本實施例中，係對於下述之2種情況_ 進行了 AES分析：在將自然氧化物除去後的 藉由 CVD法，而在成膜壓力：500Pa、基板 、還原氣體流量：500sccm的製程條件下，·( 材料，而使用 Co(tBu-Et-Et-amd)2，並作爲完 使用H2來形成了 30nm之H2還原鈷膜的t CVD法，而在成膜壓力：5 00Pa、基板溫度 原氣體流量：50〇SCCm的條件下，作爲有機3 使用Co(tBu-Et-Et-amd)2，並作爲還原氣體， 、（:〇核之生 料之分解並 i明之鈷膜的 體。 體的NH3， 中所選擇之 、NH(CH3)2 合之氣體的 係得知：與 幾乎成爲〇 ‘的各試料而 Si基材上， 溫度：3 0 0 〇C :爲有機金賜 :原氣體，而 ί況；和藉由 :3 00 °C、還 :屬材料，而 而使用將H2 -12- 201124552 來與N Η 3作了組合的氣體，來形成了 3 0 n m之 原鈷膜的情況。 將所得到之結果展示於圖4 ( a )以及（b ) 4 ( a )中所示一般，當H2還原鈷膜的情況時， 3 0 %的C之雜質量，相對於此，如圖4(b)中 ，當Η2·ΝΗ3還原鈷膜的情況時，C之雜質量 爲少。 [實施例4] 代替在實施例3中所使用之Η2-ΝΗ3還原氣 用ΝΗ3還原氣體，並反覆進行了實施例3之製 果，所得到之ΝΗ3還原鈷膜，係得到了與實施1 況時相同之AES分析結果。 [實施例5] 在本實施例中，係在成膜C 〇前，先對於S i 而藉由nh3氣體來進行了前置處理。 準備φ 3 0 0 n m之s i基板，並藉由乾蝕刻來 面而將自然氧化膜除去，之後，作5分鐘之大氣 著，作爲有機金屬材料，而使用雙烷基脒基鈷（ 係爲乙基、丁基），並作爲還原氣體，而使用 由CVD法，而在成膜壓力：20〇Pa、基板溫度 還原氣體流量：3〇Osccm、成膜時間：1〇分鐘的 下，而形成了 H2還原鈷膜。又，在將自然氧化 H2-NH3 還 中。如圖 係包含有 所示一般 :爲5 %而 體，而使 程，其結 U 3的情 基板表面 從其之表 開放，接 此烷基， H2，再藉 ：2 00 °C、 製程條件 膜除去後 -13- 201124552 亦同樣的作了大氣開放之Si基板的表面上，使nh3作了 吸附（成膜壓力：5 00Pa、基板溫度：200°c、還原氣體（ NH3 )流量：30〇SCCm、處理時間：5分鐘），之後，使用 相同之有機金屬材料以及還原氣體，而在相同之CVD製 程條件下，形成了 H2還原鈷膜。 將如此這般所得到之Si基板表面的SEM照片，展示 於圖5 ( a )以及（b )中。當並未將NH3作吸附的情況時 ，在Si基板表面上，係幾乎不會產生Co之核，而並未被 形成有鈷膜（圖5(a))，但是，當將NH3作了吸附的 情況時，可以得知，相較於並不作吸附的情況，Co之核 係有所成長，並且被形成有鈷膜（圖5(b))。此事， 係代表著：藉由將被終端於Si之懸鍵處的Η置換爲NH， 核成長係被促進，並代表著：藉由將ΝΗ3作表面吸附， 係能夠對於核生成時間作抑制。於圖6中，展示相關於此 點之Si基板表面上的示意圖。圖6(a)，係爲並未將 NH3作表面吸附的情況，圖6(b)，係爲將NH3作了表 面吸附的情況。 [實施例6] 在本實施例中，係依據實施例5，而對於並不將NH3 作表面吸附地而成膜了 H2還原Co的情況和將NH3作了 表面吸附地而成膜H2還原Co的情況中之Si基板上的表 面形態作了檢討。其結果，將NH3作了表面吸附的情況 下之表面形態，係爲良好。 -14- 201124552 [實施例7] 在本實施例中，係對於使基板溫度在1 9 0 °C〜3 2 0 °C間 作變動並根據實施例3所記載之方法所得到的Η 2還原鈷 膜以及Η2-ΝΗ3還原鈷膜之相對於比電阻的溫度依存性作 了檢討。 亦即是，將並未除去自然氧化物之S i基板溫度設定 爲 2 5 0 °C〜3 2 0 t ，並在此基板上，作爲還原氣體而以 30〇SCCm來供給H2氣體，並作爲有機金屬材料，而將雙 烷基脒基鈷·_ Co(tBu-Et-Et-amd)2藉由防護筒（Canister )來加溫至60°C〜9〇t：，且作爲載體氣體，而以30〇SCcm 來流動載體氣體，並根據CVD法，來在200Pa之壓力下 而形成了 H2還原鈷膜。又，將與上述相同之並未除去自 然氧化物的Si基板溫度設定爲190°C~30(TC，並在此基 板上，作爲還原氣體而分別以200 seem以及40〇SCCm來供 給H2與NH3之混合氣體，並作爲有機金屬材料，而將雙 烷基脒基鈷：C〇(tBu-Et-Et-amd)2藉由防護筒（Canister )來加溫至60t〜90°C並作供給，並根據CVD法，來在 2 0 0Pa之壓力下而形成了 H2-NH3還原鈷膜。 對於如此這般所得到之H2-還原鈷膜與Η2·ΝΗ3還原 鈷膜，藉由4端子法而測定出比電阻（V Ω · cm )，並 將其結果描繪於圖7中。如同由圖7而能夠明顯得知一般 ，在Η 2 -還原鈷膜的情況中，比電阻係爲高，並且由基板 溫度所導致之比電阻的變動係爲劇烈，但是，在Η 2 - Ν Η 3 還原鈷膜的情況中，相較於Η2-還原鈷膜的情況，比電阻 -15- 201124552 係爲低，並且溫度依存性係爲少。 [產業上之利用可能性] 若依據本發明，則所得到之鈷膜 Co之核生成時間、將鈷膜低電阻化、 作低溫成膜，而使鈷膜之使用溫度區域 成爲能夠將鈷膜利用在細微圖案加工中 係能夠利用在半導體裝置之技術領域中 【圖式簡單說明】 [圖1 ]對於先前技術的情況時之空 式圖，（a )以及（b )，係爲對於由於 致的空洞之產生作展示之圖，又，（c) 對於由於在孔側面之阻障膜的非對稱性 生作展示之圖。 [圖2]對於由於先前技術所導致之 之SEM照片（a )以及其之模式圖（b ) [圖3]對於藉由實施例1所得到之] 及H2還原鈷膜的成膜時間（分鐘）與 之成膜速率（lnm/分）的膜厚（nm) f 圖表。 [圖4]係爲對於針對藉由實施例3 行的AES分析結果作展示之圖表，（s 原鈷膜的情況下之AES分析結果作展歹 ，係成爲能夠縮短 改善表面形態、並 增廣，藉由此，而 ，因此，本發明， 洞產生作展示的模 孔上部之懸垂所導 以及（d )，係爲 所導致的空洞之產 空洞的產生作展示 〇 ί；!-ΝΗ3還原鈷膜以 相當於每單位時間 蜀之關係作展示的 所得到之鈷膜所進 ι )係爲對於Η 2還 民的圖表，（b )係 -16- 201124552 爲對於H2-NH3還原鈷膜的情況下之AES分析結果作展示 的圖表。 [圖5 ]係爲藉由實施例5所得到了的S i基板表面之 S EM照片，（a )係爲並未將NH3作吸附的情況時之基板 表面的SEM照片，（b )係爲將NH3作了吸附的情況時之 基板表面的S E Μ照片。 [圖6]係爲藉由實施例5所得到了的Si基板表面之示 意，（a )係爲並未將NH3作表面吸附的情況，（b )係爲 將NH3作了表面吸附的情況。 [圖7 ]係爲對有關於藉由實施例7所得到了的H2還原 鈷膜和Η2·ΝΗ3還原銘膜之基板溫度與比電阻値之間的關 係作展示之圖表。 【主要元件符號說明】 101、2 0 1 :基板 1 0 2 :阻障膜 103 : PVD-種晶膜 1〇4 : Cu 膜 2 02 : TiN阻障膜 203: CVD-Cu 膜 -17-201124552 VI. Description of the Invention: [Technical Field to Which the Invention Is Ascribed] The present invention relates to a method of forming a cobalt film. [Prior Art] In the current Cu wiring film formation process, a PVD-barrier film (such as a PVD-Ti film or a Ta film) and a PVD- seed film (PVD-Cu film) are in a constant vacuum (in- Situ) is formed, and then, Cu plating engineering, C Μ P engineering is performed. However, due to the miniaturization of the wiring in recent years, the asymmetry or 悬verhang of the wafer edge of the VD film became significant after the device node 3 2 nm generation, and it was produced in the electroplating process. The problem of holes (V 〇id ). Here, the P V D -barrier film means a barrier film formed by the p v 〇 method, and the p V D - seed film refers to a seed film formed by the p V D method. The P V D ( C V D ) - c u film, the A L D - barrier film, and the (C V D, A L D )-cobalt film described below are the respective films formed by p V D and C V D ' A L D , respectively. For example, as shown in FIGS. 1(a) and (b), if it is formed on a barrier film 10 2 formed on a substrate provided with a hole of 4 32 nm or a trench, pv D is formed. - seed film 1 〇 3 ( pv D _ cu film) 'The hole or the upper part of the trench will have a dangling (Part A) and the opening of the hole etc. will be narrowed by $, and then by electroplating When the inside of the hole or the like is buried by the Cu film 丨04, the plating liquid system becomes difficult to enter into the inside, and the adhesion between the Cu film and the barrier film is also poor, so that -5 to 201124552, As the Cu film is buried, the Cu film system is sucked up, and there is a problem that voids (Part B) are generated in the Cu film. Further, as shown in Figs. 1 (^) and (d), generally, at the side of the hole or the like, the PVD- seed crystal film 1 0 3 (part C) cannot be formed uniformly and symmetrically, but is caused by this. The asymmetry of the barrier film, in the Cu film 104 buried in the subsequent electroplating process, there is also a problem of voids (part D). The barrier film formed by the ALD method or the CVD method and the CVD-Cu film have no problem of asymmetry or drape, and therefore, attempts have been made to form Cu wiring using these two processes. A method of a film (for example, refer to Patent Document 1). However, the problem in this case is that since the adhesion between the CVD-Cu film and the ALD-barrier film of the underlying film is low, voids are generated in the Cu film. Case. Therefore, the current system has not been put into practical use. For example, as shown in FIGS. 2(a) and (b), a TiN barrier film (ALD-TiN barrier film) is formed by an ALD method in a hole or a trench provided in the substrate 20 1 . 202. Then, when the inside of the hole or the like is buried by the CVD-Cu film 203, a void (Part A) is generated inside the Cu film. Fig. 2(a) shows an SEM photograph of a cross section of a substrate in a state in which it is buried by a CVD-Cu film 203, and Fig. 2(b) is a schematic view thereof. In order to eliminate the voids in the Cu film which are caused by the poor adhesion between the CVD-Cu film and the ALD-block film which is the base film of the substrate as described above, and for the barrier/density In order to improve the performance of the film, it is attempted to use a cobalt film which is excellent in coverage and low in resistance under the film, and the development of the film formation technology of cobalt film by the -6-201124552 c VD method or the ALD method. , is a matter of urgency. For the cobalt film, not only in the field of the Cu wiring film, but also in the field of the deuterated layer or the cap layer, the demand for the cobalt film having a high coverage is also increasing. In contrast, in the case of a cobalt film obtained by a CVD method using an organometallic material of Co and an amine by the prior art (for example, 'Reference Patent 2'), the growth time of the 'C nucleus' It is long for 20 minutes, and the growth rate of the Co core is slow for 1 nm/min. Moreover, there is also a problem that the impurity concentration of C is 30%. [PRIOR ART DOCUMENT] [Patent Document 1] JP-A-2003-055769 [Patent Document 2] JP-A-2006-299407 SUMMARY OF INVENTION [Problems to be Solved by the Invention] The present invention The subject 'is to solve the above problems of the prior art' is to provide a method of forming a cobalt film by a CVD method or the like using a specific reducing gas. [Means for Solving the Problem] The method for forming a cobalt film of the present invention is a method for forming a cobalt film on the surface of a Si substrate as a substrate, which is characterized in that: alkyl sulfonium cobalt 201124552 is used, and Nh3, n2h4, nh(ch3)2, n2h3ch, and n2 are selected as the reducing gas or the gas of h2 and the reducing gas is formed to form a cobalt film. In this way, by using NH3 as a reducing gas instead of the previous h2 gas or in addition to the h2 gas, it is possible to suppress the generation time of Co nucleus, control the degree of cobalt film, and improve the surface morphology (m 0 Rph ο 10 gy ), suppressing the impurity concentration to be low-resistance, and making the cobalt film usable in the semiconductor device pattern. In the method for forming a cobalt film, the surface is subjected to a pretreatment for nh3 on the surface of a substrate such as a Si substrate, and then an alkyl group such as a dialkyl fluorenyl group is used. The cobalt film is formed by a sulfhydryl cobalt and a reducing gas selected from nh3, n2h4, nh(ch3)2, n2h, and n2, h2, or a gas combining h2 and a raw gas. In this way, by pre-treating with NH3 for a substrate as a Si substrate, it is possible to suppress the formation of a nucleus of Co, control the formation of a cobalt film, and improve the surface morphology by using reduction. m 〇rph ο 1 〇 gy ), suppressing the impurity concentration, and reducing the resistance, so that the cobalt film can be utilized in the case of a semiconductor device. The present invention is characterized in that the alkane cobalt is Co(tBu-Et-Et-amd)2. The growth rate of the gas, etc. of the selected combination technology is fine: that is, the surface gas of the above-mentioned common 3CH is used for the long-term speed and becomes a fine-grained base plug 201124552 [Effect of the invention] According to the invention, the cobalt film formed by using only ruthenium 2 as the reducing gas in the prior art is used, and the cobalt film formed by using NHS or the like as a reducing gas is not used for the pretreatment of the surface of the si substrate. And the cobalt film formed by using I and/or NH3 as a reducing gas after pre-treatment with NH3 on the surface of the Si substrate, is capable of suppressing the nucleation time of C 、, By reducing the resistance of the cobalt film, improving the surface morphology (m 〇rph 〇1 0 gy ), and forming a film at a low temperature, it is possible to achieve the following effects: that is, in the semiconductor device fabrication process. The productivity can be improved, and the cobalt film can be utilized in fine processing by expanding the temperature range of use of the film. Further, according to the present invention, the cobalt film can be formed by the c VD method or the A LD method, and the film can be thinned, and the cobalt film can be used in a semiconductor device. In the project. [Embodiment] The embodiment of the method for forming a cobalt film according to the present invention is a method of forming a film on the surface of a substrate which is a substrate as a substrate, and is used as a double The alkyl fluorenyl cobalt generally comprises a C 0 and an organometallic material of a fluorenyl group (this alkyl group is an ethyl group, a butyl group) and as a reduction for the reduction of the organometallic material and formation of a cobalt film. The gas is a reducing gas selected from the group consisting of NH3, N2H4, N^UCH3)2, N2H3CH and N2, which are known as reducing gases, or 201124552, H2 and the aforementioned reducing gas (in particular among them, nh3) Ideally, a combined gas can be formed by a CVD method or an ALD method at a film formation pressure: 1 〇〇 lOOOPa, a substrate temperature: 200 to 400 ° C, a reducing gas (for example, NH 3 ) flow rate: 100 〜 Under the condition of lOOOsccm, a CVD (ALD)-cobalt film is formed, and by using such a reducing gas, it is possible to suppress the generation time of Co nucleus, control the growth rate of the cobalt film, improve the surface morphology, and suppress the impurity concentration. and Of low resistance, of the cobalt film in a fine pattern as adhesion layer, silicide layer, using the cap layer is made possible. In the above-described method for forming a cobalt film, it is possible to form a film on a surface similar to that of a Si substrate, and a film formation pressure: 1 〇〇 to 1000 Pa, a substrate temperature: 200 to 400 ° C, and a gas flow rate: 100. ~lOOOOsccm Under normal conditions, the pretreatment is carried out by nh3, after which an organometallic material containing Co and an alkyl fluorenyl group as in the case of a dialkyl fluorenyl cobalt is used, and is recovered by a well-known method. The reducing gas or h2 selected in the nh3, n2h4, nh(ch3)2, n2h3ch and n2 of the gas is also combined with h2 and the aforementioned reducing gas (especially nh3 in particular) The gas' is known by the CVD method or the ALD method (for example, film formation pressure: 1 0 0 to 1 0 0 P a, substrate temperature: 200 to 400 ° C, reducing gas flow rate: 100) ~1000sccm), a CVD (ALD)-cobalt film is formed, and after such a pre-treatment of the surface of the Si substrate by NH3, the gas is used to suppress Co. Nuclear generation time, control of the growth rate of cobalt film, and improvement of surface morphology (m r p h ο 1 billion g y), the impurity concentration of inhibition, and into a low resistance -10-201124552, the cobalt film of the fine pattern as in the adhesion layer, a silicon layer, using the cap layer is made possible. The organometallic material formed of the above alkyl fluorenyl cobalt may, for example, be Co(tBu-Et-Et-amd) 2 or the like. [Example 1] In the present example, the relationship between the film thickness (nm) of the film formation time (minute) was examined in the following two cases: Si after removal of the natural oxide On the substrate, by the CVD method, under the conditions of film formation pressure: 500 Pa, substrate temperature: 300 ° C, and reducing gas flow rate: 20 〇 sccm, Co(tBu-Et-Et- is used as the organic metal material. Amd)2, and as a reducing gas, only NH3 is used to form a cobalt film (NH3 reduced cobalt film); and by CVD method, at film forming pressure: 50,000 Pa, substrate temperature: 30,000 t, reducing gas flow rate: 20 〇 SCCm under the condition of 'as an organometallic material, and using C 〇 (tBu-Et-Et-amd) 2, and as a reducing gas, using H2 to form a cobalt film (H2 reduced cobalt The case of the membrane). This film thickness corresponds to the film formation rate per unit time. The results obtained are shown in Figure 3. As is apparent from Fig. 3, in the case where the cobalt film is reduced by H2, the film formation rate is 1 nm/min, and the nucleation time is 20 minutes. In contrast, when NH3 is used to reduce the cobalt film, The film formation rate was 8 nm/min, and the nucleation time was 〇, so it was found that the nucleus was immediately generated and film formation was started immediately. It is conceivable that the smoothing of the surface of the cobalt film caused by the decrease in the amount of impurities caused by the use of these NH3 as a reducing gas -11 - 201124552, the low resistance of the cobalt film, and the film formation rate of the cobalt film The increase in the time is shortened because the NH3 radical promotes the original and the partial pressure of Co increases. Therefore, in the formation of the present invention, it is possible to use a reducing gas which generates such a radical [Example 2], instead of using n2h4, nh(ch3)2, n2h3ch and instead of the use as the reduction in the use in Example 1. In the case of the n2 reducing gas, and the case where the reducing gas selected from NH:, N2H3CH, and N2 is used, the process of the first embodiment is repeated, and the case of the first embodiment is the same. The generation time of the Co nucleus, {;, the nucleus was immediately produced and began to form a film. [Example 3] In the present example, AES analysis was carried out for the following two cases: CVD method after removal of natural oxide, film formation pressure: 500 Pa, substrate, reducing gas Flow rate: 500 sccm process conditions, · (Material, Co(tBu-Et-Et-amd) 2 was used, and the T CVD method of forming a 30 nm H2 reduced cobalt film using H2 was completed, and the film formation pressure was observed. : 5 00Pa, substrate temperature, raw gas flow rate: 50 〇 SCCm, Co(tBu-Et-Et-amd) 2 is used as the organic 3, and as a reducing gas, (: decomposition of the raw material of the nucleus) The body of the cobalt film of the body, the NH(CH3)2 gas selected from the body NH3, is known to be almost the same as the sample of the 〇', and the temperature is 3 0 0 〇C: For organic gold: the original gas, and the condition; and by: 3 00 °C, also: a material, and the use of H2 -12- 201124552 to combine with N Η 3 gas to form 3 The case of the original cobalt film of 0 nm. The results obtained are shown in Fig. 4 (a) and (b) 4 (a). Generally, when H2 is used to reduce the cobalt film, 3 In contrast to the case where the cobalt film is reduced by Η2·ΝΗ3, the amount of impurities of C is small as shown in Fig. 4(b). [Example 4] Instead of the example 3 The ruthenium-ruthenium reduction gas used in the reduction of ruthenium 3 was used, and the result of Example 3 was repeated, and the obtained ruthenium 3 reduced cobalt film was obtained in the same manner as in the case of the first embodiment. [Example 5] In the present embodiment, the pre-treatment is performed by nh3 gas for S i before the formation of C 。. The si substrate of φ 3 0 0 nm is prepared, and the surface is naturally dried by dry etching. The oxide film is removed, and then it is made to stand for 5 minutes. As an organic metal material, a dialkyl fluorenyl cobalt (e.g., ethyl or butyl group) is used as a reducing gas, and a CVD method is used. Membrane pressure: 20 〇 Pa, substrate temperature, reducing gas flow rate: 3 〇 Osccm, film formation time: 1 〇 minute, and H2 reduced cobalt film was formed. Further, natural oxidation of H2-NH3 was also carried out. Contains the general: shown as 5%, while the process, its junction U 3, the surface of the substrate from its surface Put, connect this alkyl group, H2, and then borrow: 2 00 °C, after the process condition film is removed - 13-201124552 The same is made on the surface of the open Si substrate, so that nh3 is adsorbed (film formation pressure: 5 00Pa, substrate temperature: 200 ° C, reducing gas (NH3) flow rate: 30 〇 SCCm, processing time: 5 minutes), after that, using the same organometallic material and reducing gas, under the same CVD process conditions, The H2 reduced cobalt film. The SEM photograph of the surface of the Si substrate thus obtained is shown in Figs. 5(a) and (b). When NH3 is not adsorbed, a core of Co is hardly formed on the surface of the Si substrate, and a cobalt film is not formed (Fig. 5(a)), but when NH3 is adsorbed In the case of the case, it can be known that the core of Co grows and the cobalt film is formed as compared with the case where it is not adsorbed (Fig. 5(b)). This matter is represented by the fact that the nuclear growth system is promoted by replacing the enthalpy at the dangling bond of Si with NH, and it is represented by the surface adsorption of ΝΗ3, which suppresses the nucleation time. . In Fig. 6, a schematic view on the surface of a Si substrate relating to this point is shown. Fig. 6(a) shows a case where NH3 is not surface-adsorbed, and Fig. 6(b) shows a case where NH3 is surface-adsorbed. [Example 6] In the present example, according to Example 5, H2 reduction of Co was formed by forming NH2 without surface adsorption, and H2 reduction of Co was formed by surface adsorption of NH3. The surface morphology on the Si substrate was reviewed in the case. As a result, the surface morphology in the case where NH3 was surface-adsorbed was good. -14-201124552 [Example 7] In the present example, Η 2 reduction was carried out according to the method described in Example 3, with the substrate temperature varying between 19 ° C and 30 ° C. The temperature dependence of the cobalt film and the Η2-ΝΗ3 reduced cobalt film with respect to specific resistance was reviewed. That is, the temperature of the Si substrate on which the native oxide is not removed is set to 250 ° C to 3 2 0 t, and on the substrate, H 2 gas is supplied as a reducing gas at 30 〇 SCCm, and An organometallic material, and the bis-alkyl fluorenyl cobalt _ Co(tBu-Et-Et-amd) 2 is heated to 60 ° C to 9 〇 t: by a canister, and as a carrier gas, The carrier gas was flowed at 30 〇SCcm, and an H2 reduced cobalt film was formed under a pressure of 200 Pa according to the CVD method. Further, the temperature of the Si substrate which is not removed from the natural oxide is set to 190 ° C to 30 (TC), and H2 and NH 3 are supplied as 200 m and 40 〇 SCCm as reducing gas on the substrate. a mixed gas and as an organometallic material, and the dialkyl fluorenyl cobalt: C 〇 (tBu-Et-Et-amd) 2 is heated to a temperature of 60 t to 90 ° C by a canister. According to the CVD method, a H2-NH3 reduced cobalt film is formed under a pressure of 200 Pa. The thus obtained H2-reduced cobalt film and Η2·ΝΗ3 reduced cobalt film are obtained by a 4-terminal method. The specific resistance (V Ω · cm ) was measured, and the results are shown in Fig. 7. As is apparent from Fig. 7, in general, in the case of the Η2-reduced cobalt film, the specific resistance is high, and The variation of the specific resistance caused by the substrate temperature is severe, but in the case of Η 2 - Ν Η 3 reduction of the cobalt film, compared with the case of the Η2-reduced cobalt film, the specific resistance is -15-201124552. And the temperature dependence is small. [Industrial Applicability] According to the present invention, the obtained cobalt film Co The nucleation time, the low-resistance of the cobalt film, and the low-temperature film formation, and the use of the cobalt film in the use of the cobalt film in the fine pattern processing can be utilized in the technical field of the semiconductor device. 】 [Fig. 1] For the space diagram in the case of the prior art, (a) and (b) are diagrams showing the generation of voids due to the resulting holes, and (c) for the resistance due to the side of the holes. Asymmetric display of the barrier film. [Fig. 2] For the SEM photograph (a) due to the prior art and its pattern (b) [Fig. 3], obtained by the example 1. ] and H2 reduction film formation time (minutes) and film formation rate (lnm/min) film thickness (nm) f chart [Fig. 4] is for AES analysis results for Example 3 row As a graph for display, (the result of the AES analysis in the case of the original cobalt film is to be able to shorten the surface morphology and enlarge the surface, thereby, therefore, the present invention, the hole is produced as a model for display. The overhang of the upper part of the hole and (d) are caused by The production of voids is shown as a display of 空 ; ; ! 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原 还原)-16- 201124552 is a graph showing the results of AES analysis in the case of reducing the cobalt film by H2-NH3. [Fig. 5] is a S EM photograph of the surface of the Si substrate obtained by Example 5, ( a) is a SEM photograph of the surface of the substrate when NH3 is not adsorbed, and (b) is a SE Μ photograph of the surface of the substrate when NH3 is adsorbed. Fig. 6 is a view showing the surface of the Si substrate obtained in Example 5, wherein (a) is a case where NH3 is not adsorbed on the surface, and (b) is a case where NH3 is surface-adsorbed. Fig. 7 is a graph showing the relationship between the substrate temperature and the specific resistance 有 of the H2 reduced cobalt film and the Η2·ΝΗ3 reduction film obtained in Example 7. [Main component symbol description] 101, 2 0 1 : substrate 1 0 2 : barrier film 103 : PVD - seed film 1〇 4 : Cu film 2 02 : TiN barrier film 203: CVD-Cu film -17-