JP2004146780A

JP2004146780A - Polishing liquid composition

Info

Publication number: JP2004146780A
Application number: JP2003159884A
Authority: JP
Inventors: Shigeaki Takashina; 高階　重昭; Yasuhiro Yoneda; 米田　康洋; Toshiya Hagiwara; 萩原　敏也
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2002-08-28
Filing date: 2003-06-04
Publication date: 2004-05-20
Anticipated expiration: 2023-06-04
Also published as: JP3926293B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing liquid composition for flattening a semiconductor substrate in a short period of time, a polishing method for flattening the semiconductor substrate by using the composition, and a method of manufacturing the semiconductor device by polishing the semiconductor substrate with the composition. <P>SOLUTION: The polishing liquid composition contains an aqueous medium and abrasive particles. In the abrasive particles, a content of abrasive particles with a particle size of 2 to 200 nm is 50 vol.% or higher. A content of small abrasive particles with a grain size of no smaller than 2 nm and no larger than 58 nm is 40 to 75 vol.% in a total content of abrasive particles with a grain size of 2 to 200 nm. A content of middle grain size abrasive particles with a grain size of no smaller than 58 nm and no larger than 75 nm is 0 to 50 vol.% in a total content of the abrasive particles with a grain size of 2 to 200 nm. A content of large grain size abrasive particles with a grain size of 75 to 200 nm is 10 to 60 vol.% in a total content of the abrasive particles with a grain size of 2 to 200 nm. There are provided: the polishing method for flattening the semiconductor substrate by using the composition, the method of flattening the semiconductor substrate, and the method of manufacturing the semiconductor device with a step of polishing the semiconductor substrate. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は研磨液組成物、該研磨液組成物を用いる研磨方法、半導体基板の平坦化方法、並びに半導体装置の製造方法に関するものである。更に詳しくは、本発明は特に薄膜を形成した表面に凹凸を有する半導体基板を平坦化する際に有用な研磨液組成物、およびこの研磨液組成物を用いて半導体基板を平坦化する研磨方法、この研磨液組成物を用いる半導体基板の平坦化方法並びにこれらを用いて半導体基板を研磨する工程を有する半導体装置の製造方法に関するものである。
【０００２】
【従来の技術】
現在の超々大規模集積回路では、トランジスタおよび他の半導体素子を縮小して実装密度を高める傾向にある。このため、種々の微細加工技術が開発されている。その技術の一つに化学的機械的研磨（Ｃｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ　、略してＣＭＰ）技術がある。この技術は、半導体装置の製造工程において、例えば埋め込み素子分離、層間絶縁膜の平坦化、埋め込み金属配線形成、プラグ形成、埋め込みキャパシタ形成等を行う上で大変重要な技術である。中でも、種々の金属、絶縁膜等を積層する際に行う、研磨表面の凹凸部の段差を低減させる平坦化は、半導体装置の微細化、高密度化の点から重要な工程であり、速やかに平坦化を実現することが求められている。
【０００３】
上記製造工程で用いられるＣＭＰ用研磨液としては、一例として水に研磨粒子を分散させたものが用いられる。従来、この研磨粒子にはヒュームドシリカ、あるいはアルミナなどが使用されている。中でも安価で高純度なことからヒュームドシリカが多用されているが、製造過程で凝集粒子（二次粒子）を形成していることからスクラッチを誘発しやすい欠点がある。その一方でコロイダルシリカと称されるシリカ砥粒は、粒子の表面形状が比較的球状であり、かつ単分散に近く凝集粒子を形成し難いため、低スクラッチ化を期待できることで使用され始めているが一般に研磨速度が低いという欠点がある。
【０００４】
コロイダルシリカを用いた研磨液組成物については、特定粒径分布を有するシリカ研磨液が特許文献１に開示されているが、被研磨面の表面粗さを５〜１５Å程度から３Å以下に低減することを主眼としており、この特定粒径分布では半導体基板表面の１００〜２００００Åの凹凸段差を平坦化するには時間がかかる。
【０００５】
また、特許文献２では、粒径が異なる２種のコロイダルシリカの混合物を用いた研磨用組成物により平均うねりの少ない研磨面（数Å以下）を得ることが開示されている。この平均うねりの少ない研磨面（数Å以下）を得るという課題は例えばハードディスクのいわゆる仕上げ研磨工程において生じる初期被研磨面の平均うねりが数１０Åで研磨後面の平均うねりが数Å以下となるようなものにおける課題であり、従って、ここに具体的に開示されている平均うねりが数Å以下の研磨面とはハードディスクの仕上げ研磨についてのことであり、本発明が対象とする凹凸段差を有する被研磨面、例えば半導体基板等の平坦化とは本質的に異なる。
【０００６】
さらに特許文献３には集積回路を平坦化するため、平均粒子径が２〜３０ｎｍの小研磨粒子と、その２〜１０倍の平均粒子径を有する大研磨粒子から成り、小研磨粒子と大研磨粒子とが体積比５：１〜１００：１であるスラリーを用いたＣＭＰ方法が開示されているが、小研磨粒子が８３％以上と大部分を占めているため研磨速度が低く、平坦化完了までに要する研磨時間が長くなるため、平坦化効率という観点で不十分である。
【０００７】
【特許文献１】
特開２００１−３２３２５４号公報
【特許文献２】
特開２００２−３０２７４号公報
【特許文献３】
米国特許第６１４３６６２号公報
【０００８】
【発明が解決しようとする課題】
本発明の目的は、短時間に表面に凹凸を有する被研磨面半導体基板を平坦化することができる研磨液組成物、この研磨液組成物を用いて凹凸を有する被研磨面半導体基板を平坦化する研磨方法、半導体基板の平坦化方法、並びにこれらを用いて半導体基板を研磨する工程を有する半導体装置の製造方法を提供することにある。
【０００９】
【課題を解決するための手段】
即ち、本発明の要旨は、
〔１〕　水系媒体と研磨粒子を含んでなる研磨液組成物であって、該研磨粒子中における粒子径２〜２００ｎｍの研磨粒子含有量が５０体積％以上であり、該研磨粒子として粒子径が２〜５８ｎｍ未満の小粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中４０〜７５体積％含有し、粒子径が５８〜７５ｎｍ未満の中粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中０〜５０体積％含有し、粒子径が７５〜２００ｎｍの大粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中１０〜６０体積％含有する研磨液組成物、
〔２〕　水系媒体と研磨粒子を含んでなる研磨液組成物であって、研磨粒子が平均粒子径が２〜５０ｎｍである研磨粒子群（Ａ）と、平均粒子径が５２〜２００ｎｍである研磨粒子群（Ｂ）とを含み、ＡとＢの重量比（Ａ／Ｂ）が０．５／１〜４．５／１である、研磨液組成物、
〔３〕　前記〔１〕又は〔２〕記載の研磨液組成物を用いて、半導体基板を平坦化する研磨方法、
〔４〕　前記〔１〕又は〔２〕記載の研磨液組成物を用いる、半導体基板の平坦化方法、
〔５〕　前記〔１〕又は〔２〕記載の研磨液組成物を用いて半導体基板を研磨する工程を有する半導体装置の製造方法
に関する。
【００１０】
【発明の実施の形態】
本発明の研磨液組成物としては、前記のように、
（態様１）水系媒体と研磨粒子を含んでなる研磨液組成物であって、該研磨粒子中における粒子径２〜２００ｎｍの研磨粒子含有量が５０体積％以上であり、該研磨粒子として粒子径が２〜５８ｎｍ未満の小粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中４０〜７５体積％含有し、粒子径が５８〜７５ｎｍ未満の中粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中０〜５０体積％含有し、粒子径が７５〜２００ｎｍの大粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中１０〜６０体積％含有する研磨液組成物、及び
（態様２）水系媒体と研磨粒子を含んでなる研磨液組成物であって、研磨粒子が平均粒子径が２〜５０ｎｍである研磨粒子群（Ａ）と、平均粒子径が５２〜２００ｎｍである研磨粒子群（Ｂ）とを含み、ＡとＢの重量比（Ａ／Ｂ）が０．５／１〜４．５／１である、研磨液組成物
の２つの態様が挙げられる。
【００１１】
態様１及び２において、前記研磨粒子としては、例えば無機粒子が挙げられる。金属、金属又は半金属の炭化物、金属又は半金属の窒化物、金属又は半金属の酸化物、金属又は半金属のホウ化物、ダイヤモンド等が挙げられる。金属又は半金属元素は周期律表の３Ａ、４Ａ、５Ａ、３Ｂ、４Ｂ、５Ｂ、６Ｂ、７Ｂ又は８Ｂ族に属するものが挙げられる。その例として、二酸化ケイ素、酸化アルミニウム、酸化セリウム、酸化チタン、酸化ジルコニウム、窒化ケイ素、二酸化マンガン、炭化ケイ素、酸化亜鉛、ダイヤモンド及び酸化マグネシウムが挙げられる。
【００１２】
これらの中でも好ましくは、二酸化ケイ素、酸化アルミニウム、酸化セリウムであり、スクラッチ低減の観点から、二酸化ケイ素がより好ましい。この具体例として、二酸化ケイ素としては、コロイダルシリカ粒子、フュームドシリカ粒子、表面修飾したシリカ粒子等；酸化アルミニウムとしては、α―アルミナ粒子、γ―アルミナ粒子、δ―アルミナ粒子、θ―アルミナ粒子、η―アルミナ粒子、無定型アルミナ粒子、その他の製造法の異なるフュームドアルミナやコロイダルアルミナ等；酸化セリウムとしては、酸化数が３価又は４価のもの、結晶系が、六方晶系、等軸晶系又は面心立方晶系のもの等が挙げられる。
【００１３】
さらにこれらの中でもより好ましくは、コロイダルシリカ粒子である。コロイダルシリカ粒子は形状が比較的球形であり、一次粒子の状態で安定に分散でき凝集粒子を形成し難いため被研磨表面に対してスクラッチを低減できる。コロイダルシリカ粒子は、ケイ酸ナトリウム等のケイ酸アルカリ金属塩を原料とする水ガラス法またはテトラエトキシシラン等を原料とするアルコキシシラン法で得ることができる。これらの研磨粒子は、単独で又は２種以上を混合して用いてもよい。
【００１４】
態様１において用いる研磨粒子は、粒子径２〜２００ｎｍの研磨粒子を５０体積％以上含有するものである。前記粒子径２〜２００ｎｍの研磨粒子の含有量は、平坦化特性やスクラッチ低減の観点から、７０体積％以上が好ましく、より好ましくは８５体積％以上であり、特に好ましくは９５体積％以上であり、最も好ましくは１００体積％である。
【００１５】
態様１において前記粒子径２〜２００ｎｍの研磨粒子は、その全量中、粒子径が２〜５８ｎｍ未満の小粒径研磨粒子を４０〜７５体積％、粒子径が５８〜７５ｎｍ未満の中粒径研磨粒子を０〜５０体積％、粒子径が７５〜２００ｎｍの大粒径研磨粒子を１０〜６０体積％、それぞれ含有するものである。
【００１６】
前記小粒径研磨粒子の含有量としては、平坦化特性の観点から、４２〜７３体積％が好ましく、４３〜７２体積％がより好ましい。中粒径研磨粒子の含有量としては、平坦化特性の観点から、０〜４０体積％が好ましく、０〜３０体積％がより好ましく、０〜２５体積％が特に好ましい。大粒径研磨粒子の含有量としては、平坦化特性の観点から、１３〜５５体積％が好ましく、１５〜５０体積％がより好ましい。
【００１７】
前記研磨粒子の粒径分布は、以下の方法により求めることが出来る。即ち、研磨粒子を日本電子製透過型電子顕微鏡「ＪＥＭ−２０００ＦＸ」（８０ｋＶ、１〜５万倍）で観察した写真を、パーソナルコンピューターに接続したスキャナにて画像データとして取り込み、解析ソフト「ＷｉｎＲＯＯＦ」（販売元、三谷商事）を用いて１個１個の研磨粒子の円相当径を求め、それを研磨粒子の直径と見なし、１０００個以上の研磨粒子データを解析した後、それをもとに表計算ソフト「ＥＸＣＥＬ」（マイクロソフト社製）にて研磨粒子直径から研磨粒子体積に換算する。まず、全研磨粒子中における２ｎｍ以上２００ｎｍ以下（２〜２００ｎｍ）の研磨粒子の割合（体積基準％）を計算し、さらに２ｎｍ以上２００ｎｍ以下の研磨粒子の集合全体における２ｎｍ以上５８ｎｍ未満（２〜５８ｎｍ未満）、５８ｎｍ以上７５ｎｍ未満（５８〜７５ｎｍ未満）、７５ｎｍ以上２００ｎｍ以下（７５〜２００ｎｍ）の３つの領域の割合（体積基準％）を求める。
【００１８】
態様２において用いる研磨粒子は、平坦化特性やスクラッチ低減の観点から、前記研磨粒子群（Ａ）と前記研磨粒子群（Ｂ）との合計を少なくとも５０重量％以上含有することが好ましく、より好ましくは７０重量％以上であり、更に好ましくは８５重量％以上であり、特に好ましくは９５重量％以上であり、最も好ましくは１００重量％である。
【００１９】
態様２に用いる研磨粒子のうち、研磨粒子群（Ａ）として混合される研磨粒子の平均粒子径は、研磨速度向上の観点から２〜５０ｎｍであり、好ましくは１０〜５０ｎｍであり、特に好ましくは２６〜５０ｎｍである。また研磨粒子群（Ｂ）として混合される研磨粒子の平均粒子径は、粒子の沈降・分離を防止する観点から５２〜２００ｎｍ以下であり、好ましくは５５〜１７０ｎｍ以下である。
【００２０】
態様２において、さらに平坦化特性の観点から、研磨粒子群（Ａ）として混合される研磨粒子のうち平均粒子径が最小である研磨粒子（Ｄｍｉｎ　）と、研磨粒子群（Ｂ）として混合される研磨粒子のうち平均粒子径が最大である研磨粒子（Ｄｍａｘ　）との平均粒子径比（Ｄｍａｘ　／Ｄｍｉｎ　）は３を超えることが好ましい。なお平均粒子径Ｄ（ｎｍ）は、窒素吸着法による測定で得られた比表面積Ｓ（ｍ^２／ｇ）から、Ｄ＝２７２０／Ｓとして算出できる。
【００２１】
態様２において、研磨粒子群（Ａ）と研磨粒子群（Ｂ）の重量比は、下限は平坦化特性の観点から、上限は研磨速度の観点から、ＡとＢの重量比（Ａ／Ｂ）は０．５／１〜４．５／１であり、好ましくは１．０／１〜４．０／１である。研磨粒子群（Ａ）および研磨粒子群（Ｂ）として混合できる研磨粒子は、平均粒子径が規定範囲内のものであれば、それぞれ１つ以上混合可能である。
【００２２】
また、本発明に使用される研磨粒子としては、スクラッチを低減し、短時間で平坦化させる効率的研磨の観点から、態様１及び２に使用される研磨粒子の条件を共に満足するもの、即ち、研磨粒子中における粒子径２〜２００ｎｍの研磨粒子含有量が５０体積％以上であり、該研磨粒子として小粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中４０〜７５体積％含有し、中粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中０〜５０体積％含有し、大粒径研磨粒子を粒子径２〜２００ｎｍの研磨粒子全量中１０〜６０体積％含有し、且つ平均粒子径が２〜５０ｎｍである研磨粒子群（Ａ）と、平均粒子径が５２〜２００ｎｍである研磨粒子群（Ｂ）との重量比（Ａ／Ｂ）が０．５／１〜４．５／１であるものを使用することができる。
【００２３】
態様１及び２において、研磨液組成物中の研磨粒子の含有量は、下限は研磨速度の観点、上限は分散安定性やコストの観点から、１〜５０重量％が好ましく、３〜４０重量％がより好ましく、５〜３０重量％が特に好ましい。
【００２４】
態様１及び２において水系媒体としては、水、及びアルコール等水と混じり合う溶媒との混合媒体物を使用することができるが、水を用いることが好ましい。研磨液組成物中の水系媒体の量は、下限は分散安定性の観点から、上限は研磨速度の観点から、４０〜９９重量％が好ましく、５０〜９７重量％がより好ましく、６０〜９５重量％が特に好ましい。
【００２５】
態様１及び２の研磨液組成物は、前記水系媒体と研磨粒子とを含有してなるものである。かかる研磨粒子を含む研磨液組成物は、例えば、以下の方法によって調製することができる。水系媒体中に配合し、例えば粉末状の研磨粒子であれば、必要に応じてさらに粉砕し、超音波、攪拌、混練等の機械力により強制的に分散する方法。無機粒子などで用いられる水系媒体中で粒子を成長させる方法。中でも、水系媒体中で無機粒子を成長させる方法は、得られる無機粒子が安定に分散しており、さらに粒径の制御も容易であり好ましい。
【００２６】
態様１及び２の研磨液組成物には、必要に応じて各種の添加剤を配合することができる。添加剤としては、ｐＨ調整剤、分散安定化剤、酸化剤、キレート剤、防腐剤等が挙げられる。
【００２７】
ｐＨ調整剤としては、アンモニア、水酸化カリウム、水酸化ナトリウム、水溶性有機アミン等の塩基性物質、酢酸、シュウ酸、コハク酸、グリコール酸、リンゴ酸、クエン酸、安息香酸等の有機酸及び、硝酸、塩酸、硫酸、リン酸等の無機酸等の酸性物質が挙げられる。なお、シュウ酸とコハク酸はキレート剤としても使用し得る。
【００２８】
分散安定化剤としては、アニオン系界面活性剤、カチオン系界面活性剤、ノニオン系界面活性剤等の界面活性剤、あるいは、ポリアクリル酸又はその塩、アクリル酸共重合体、エチレンオキサイド−プロピレンオキサイドブロック共重合体（プルロニック類）等の高分子分散剤等が挙げられる。
【００２９】
酸化剤としては、過酸化物、過マンガン酸又はその塩、クロム酸又はその塩、硝酸又はその塩、ペルオキソ酸又はその塩、酸素酸又はその塩、金属塩類、硫酸等が挙げられる。
【００３０】
キレート剤としては、シュウ酸、コハク酸、フタル酸、トリメリット酸等の多価カルボン酸；グリコール酸、リンゴ酸、クエン酸、サリチル酸等のヒドロキシカルボン酸；ニトリロトリ酢酸、エチレンジアミン四酢酸等のポリアミノカルボン酸；アミノトリ（メチレンホスホン酸）、１−ヒドロキシエチリデン−１，１−ジホスホン酸等のホスホン酸等が挙げられる。
【００３１】
防腐剤としては、ベンザルコニウムクロライド、ベンゼトニウムクロライド、１，２−ベンズイソチアゾリン−３−オン等が挙げられる。
【００３２】
態様１及び２の研磨液組成物のｐＨは、被研磨物の種類や要求品質等に応じて適宜決定することが好ましい。例えば、該研磨液組成物のｐＨは、被研磨物の洗浄性及び加工機械の腐食防止性、作業者の安全性の観点から、２〜１２が好ましい。また、被研磨物が半導体ウエハや半導体素子等の研磨、特にシリコン基板、ポリシリコン基板、酸化珪素膜等の研磨に用いる場合は、研磨速度向上と表面品質の向上の観点から、７〜１２がより好ましく、８〜１２がさらに好ましく、９〜１２が特に好ましい。該ｐＨは、必要により、先に挙げたｐＨ調整剤を適宜、所望量を配合することで調整することができる。
【００３３】
本発明の研磨方法は、前記態様１又は２の研磨液組成物を用いて、あるいは態様１又は２の研磨液組成物の組成となるように各成分を混合して研磨液を調製したものを用いて、被研磨表面を研磨する工程を有するものを指し、これにより特に精密部品用基板を好適に製造することができる。したがって、本発明は、半導体装置の製造方法に関する。
【００３４】
本発明の対象である被研磨物の材質は、例えば、シリコン、アルミニウム、ニッケル、タングステン、銅、タンタル、チタン等の金属又は半金属、及びこれらの金属を主成分とした合金、ガラス、ガラス状カーボン、アモルファスカーボン等のガラス状物質、アルミナ、二酸化ケイ素、窒化ケイ素、窒化タンタル、窒化チタン、ポリシリコン等のセラミック材料、ポリイミド樹脂等の樹脂などが挙げられる。特に、ガラスやＴＥＯＳ膜等の被研磨面に二酸化ケイ素を有する基板や、ポリシリコンを有する基板を研磨する際に態様１又は２の研磨液組成物（以下、本発明の研磨液組成物という）を用いた場合、効率的に平坦化が実現できる。
【００３５】
これらの被研磨物の形状には特に制限がなく、例えば、ディスク状、プレート状、スラブ状、プリズム状等の平面部を有する形状や、レンズ等の曲面部を有する形状が本発明の研磨液組成物を用いた研磨の対象となる。その中でも、ディスク状の被研磨物の研磨に適しており、特に凹凸を有する半導体基板を平坦化する目的で行う研磨に好適である。したがって、本発明は、半導体基板の平坦化方法に関する。
【００３６】
本発明に係わる凹凸を有する被研磨面において、凹凸段差は好ましくは１００〜２００００Å（１０〜２０００ｎｍ）より好ましくは１０００〜１５０００Å（１００〜１５００ｎｍ）である。ここで、凹凸段差はプロファイル測定装置（例えばＫＬＡ−Ｔｅｎｃｏｒ社製　ＨＲＰ−１００）により求めることができる。
【００３７】
半導体基板の研磨は、シリコンウェハ（ベアウェハ）のポリッシング工程、埋め込み素子分離膜の形成工程、層間絶縁膜の平坦化工程、埋め込み金属配線の形成工程、埋め込みキャパシタ形成工程等において行われる研磨があるが、特に埋め込み素子分離膜の形成工程、層間絶縁膜の平坦化工程に適している。
【００３８】
本発明の研磨液組成物を用いる研磨方法としては、特に制限はなく、一般的な方法を用いることができる。中でも好ましくは、研磨される被研磨物を保持する治具と研磨布を備える研磨装置が用いられる。研磨布としては、有機高分子系の発泡体、無発泡体、不織布状の研磨布等を張り付けた研磨盤に、上記被研磨物を保持する治具を押しつけ、あるいは、研磨布を張り付けた研磨盤に、上記被研磨物を挟み込み、本発明の研磨液組成物を被研磨物表面に供給し、一定の圧力を加えながら研磨盤や被研磨物を動かすことにより被研磨物表面を研磨する方法が挙げられる。
【００３９】
また、本発明の半導体装置の製造方法は、凹凸のある半導体基板の上方に薄膜を形成する成膜工程と、該薄膜を研磨する研磨工程とを備え、上記研磨工程において水系媒体と研磨粒子とを含んでなる本発明の研磨液組成物を該薄膜表面に供給して、凹凸のある該薄膜表面をＣＭＰにより平坦化することからなるものであり、メモリーＩＣ、ロジックＩＣ、あるいはシステムＬＳＩ等の半導体装置の製造に好適に用いられる。
【００４０】
以上の様に、本発明の研磨液組成物およびこれを用いた研磨方法並びにこれらを用いた半導体基板を研磨する工程を有する半導体装置の製造方法によって効率的に平坦化を実現することが可能となる。
【００４１】
【実施例】
実施例１〜５及び比較例１〜４
研磨粒子として、表１に記載のシリカ粒子を用いた。
【００４２】
【表１】

【００４３】
本発明の研磨液組成物を得るために、表１記載のシリカ粒子および水を用いて、表２及び表３に記載の研磨粒子濃度を有する研磨液組成物（残部は水）を調製した。また、ｐＨが１０．５〜１１．５になるように水酸化カリウム水溶液で調整した。表２に記載された研磨粒子濃度は、下記研磨装置条件および研磨速度測定方法により、研磨速度が約２３００（Å／ｍｉｎ）〔２３０ｎｍ／ｍｉｎ〕になるように決定した。
【００４４】
＜研磨装置条件＞
研磨試験機：ラップマスターＳＦＴ製　ＬＰ−５４１（プラテン径５４０ｍｍ）
研磨パッド：ロデール・ニッタ製　ＩＣ−１０００／Ｓｕｂａ４００
プラテン回転数：６０ｒｐｍ
キャリア回転数：５８ｒｐｍ
研磨液流量：２００（ｇ／ｍｉｎ）
研磨荷重：３００（ｇ／ｃｍ^２）
【００４５】
＜研磨速度測定方法＞
被研磨材として８インチ（２００ｍｍ）シリコン基板上に２μｍのＰＥ−ＴＥＯＳを成膜したものを用いて、上記設定条件で２分研磨し、その研磨前後の残存膜厚差から研磨速度（ｎｍ／ｍｉｎ）を求めた。なお残存膜厚の測定は光干渉式膜厚計（大日本スクリーン製造（株）ＶＭ−１０００）を用いた。
【００４６】
平坦化特性を評価するために、被研磨材としてＣＭＰ特性評価用市販ウェハ（商品名：ＳＫＷ７−２、ＳＫＷアソシエーテス社（ＳＫＷ　Ａｓｓｏｃｉａｔｅｓ，Ｉｎｃ．　）製：凹凸段差８０００Å（８００ｎｍ））を用いて、予め形成されたウェハ上の凹凸段差が研磨により解消されるまでの時間で評価を行った。具体的には、上記設定条件で１分研磨毎にウェハ上のＧＲＡＤＵＡＬ　Ｄ９０　パターンの凸部と凹部の残存膜厚（測定法は上記に同じ）を測定し、既知の初期段差とから知ることのできる凹凸段差量が０になる（平坦化完了）まで繰り返し、必要な研磨時間を測定した。結果は平坦化完了までの研磨時間で表し、４分以下を良好と判断するものとする（表２）。これにより各研磨液の研磨速度をいずれも２３０ｎｍ／ｍｉｎになるように処方したにもかかわらず、実施例１〜５の平坦化特性は比較例１〜４に比べて良好であることがわかる。
【００４７】
【表２】

【００４８】
【表３】

【００４９】
【発明の効果】
本発明の研磨液組成物は、凹凸のある被研磨面に対して効率的に平坦化を実現可能なものであり、該研磨液組成物を用いることにより、およびこの研磨液組成物を用いる研磨方法並びにこれらを用いた半導体基板を研磨する工程を有する半導体装置の製造方法を提供することが可能となる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing composition, a polishing method using the polishing composition, a method for planarizing a semiconductor substrate, and a method for manufacturing a semiconductor device. More specifically, the present invention is a polishing composition particularly useful when planarizing a semiconductor substrate having irregularities on the surface on which a thin film is formed, and a polishing method for planarizing a semiconductor substrate using the polishing composition, The present invention relates to a method for flattening a semiconductor substrate using the polishing composition and a method for manufacturing a semiconductor device having a step of polishing a semiconductor substrate using the same.
[0002]
[Prior art]
In today's ultra-large-scale integrated circuits, there is a trend to increase the packing density by reducing the size of transistors and other semiconductor elements. For this reason, various fine processing techniques have been developed. As one of the techniques, there is a chemical mechanical polishing (CMP) technique. This technology is a very important technology in the manufacturing process of a semiconductor device, for example, for performing buried element isolation, planarization of an interlayer insulating film, formation of a buried metal wiring, formation of a plug, formation of a buried capacitor, and the like. Above all, flattening, which is performed when laminating various metals, insulating films, and the like, and reduces the steps of uneven portions on the polished surface, is an important step from the viewpoint of miniaturization and high density of a semiconductor device, and is promptly performed. There is a need to achieve flattening.
[0003]
As a polishing liquid for CMP used in the above-mentioned manufacturing process, a liquid in which polishing particles are dispersed in water is used as an example. Conventionally, fumed silica or alumina has been used for the abrasive particles. Above all, fumed silica is frequently used because of its low cost and high purity, but it has a disadvantage that scratches are easily induced because aggregated particles (secondary particles) are formed in the production process. On the other hand, silica abrasive grains called colloidal silica have begun to be used because the surface shape of the particles is relatively spherical, and it is almost monodisperse and it is difficult to form agglomerated particles. Generally, there is a disadvantage that the polishing rate is low.
[0004]
Regarding a polishing composition using colloidal silica, a silica polishing liquid having a specific particle size distribution is disclosed in Patent Document 1, but the surface roughness of the polished surface is reduced from about 5 to 15 ° to 3 ° or less. With this specific particle size distribution, it takes time to flatten the unevenness of 100 to 20000 ° on the surface of the semiconductor substrate.
[0005]
Further, Patent Document 2 discloses that a polishing composition using a mixture of two types of colloidal silica having different particle diameters can obtain a polished surface with few average undulations (several Å or less). The problem of obtaining a polished surface with few average undulations (several Å or less) is that, for example, the average undulation of the initial polished surface generated in the so-called finish polishing step of a hard disk is several tens of Å and the average undulation of the polished surface is several Å or less. Therefore, the polished surface specifically disclosed herein having an average waviness of several Å or less refers to the final polishing of the hard disk, and the present invention is directed to a polished surface having uneven steps. It is essentially different from the planarization of a surface, for example a semiconductor substrate.
[0006]
Further, Patent Document 3 discloses a method for flattening an integrated circuit, which comprises small abrasive particles having an average particle diameter of 2 to 30 nm and large abrasive particles having an average particle diameter of 2 to 10 times that of the small abrasive particles. A CMP method using a slurry in which particles have a volume ratio of 5: 1 to 100: 1 is disclosed. However, the polishing rate is low because small abrasive particles occupy the majority of 83% or more, and the polishing rate is low. Since the polishing time required until this is long, it is insufficient from the viewpoint of planarization efficiency.
[0007]
[Patent Document 1]
JP 2001-323254 A [Patent Document 2]
JP 2002-30274 A [Patent Document 3]
US Pat. No. 6,143,662
[Problems to be solved by the invention]
An object of the present invention is to provide a polishing composition capable of flattening a polished surface semiconductor substrate having irregularities on the surface in a short time, and to planarize a polished surface semiconductor substrate having irregularities using this polishing composition. It is an object of the present invention to provide a polishing method, a method of planarizing a semiconductor substrate, and a method of manufacturing a semiconductor device having a step of polishing a semiconductor substrate using the same.
[0009]
[Means for Solving the Problems]
That is, the gist of the present invention is:
[1] A polishing composition comprising an aqueous medium and abrasive particles, wherein the content of the abrasive particles having a particle size of 2 to 200 nm in the abrasive particles is 50% by volume or more, and the particle size of the abrasive particles is Polishing particles having a particle size of 2 to 200 nm containing 40 to 75% by volume of small abrasive particles having a particle size of less than 2 to 58 nm in the total amount of the abrasive particles having a particle size of 2 to 200 nm. A polishing liquid composition containing 0 to 50% by volume of the total amount of particles, and containing 10 to 60% by volume of the large abrasive particles having a particle diameter of 75 to 200 nm in the total amount of the abrasive particles having a particle diameter of 2 to 200 nm;
[2] A polishing composition comprising an aqueous medium and abrasive particles, wherein the abrasive particles have an average particle diameter of 2 to 50 nm (A) and a polishing liquid having an average particle diameter of 52 to 200 nm. A polishing liquid composition comprising a particle group (B), wherein the weight ratio (A / B) of A and B is 0.5 / 1 to 4.5 / 1;
[3] A polishing method for flattening a semiconductor substrate using the polishing composition according to [1] or [2],
[4] A method for planarizing a semiconductor substrate using the polishing composition according to [1] or [2],
[5] A method for manufacturing a semiconductor device, comprising: polishing a semiconductor substrate using the polishing composition according to [1] or [2].
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
As the polishing composition of the present invention, as described above,
(Aspect 1) A polishing composition comprising an aqueous medium and abrasive particles, wherein the content of the abrasive particles having a particle size of 2 to 200 nm in the abrasive particles is 50% by volume or more, and the abrasive particles have a particle size of at least 50% by volume. Contains 40 to 75% by volume of the total amount of the abrasive particles having a particle size of 2 to 200 nm and a medium particle size of the abrasive particles having a particle size of 2 to 200 nm. A polishing composition containing 0 to 50% by volume based on the total amount of the abrasive particles, and 10 to 60% by volume based on the total amount of the abrasive particles having a particle size of 2 to 200 nm and large particles having a particle size of 75 to 200 nm, and 2) A polishing composition comprising an aqueous medium and abrasive particles, wherein the abrasive particles have an average particle size of 2 to 50 nm (A), and the abrasive particles have an average particle size of 52 to 200 nm. Group (B) and A The weight ratio of B (A / B) is 0.5 / 1 to 4.5 / 1, and two embodiments of the polishing composition.
[0011]
In embodiments 1 and 2, the abrasive particles include, for example, inorganic particles. Examples thereof include metal, metal or metalloid carbide, metal or metalloid nitride, metal or metalloid oxide, metal or metalloid boride, and diamond. Examples of the metal or metalloid element include those belonging to Groups 3A, 4A, 5A, 3B, 4B, 5B, 6B, 7B or 8B of the periodic table. Examples include silicon dioxide, aluminum oxide, cerium oxide, titanium oxide, zirconium oxide, silicon nitride, manganese dioxide, silicon carbide, zinc oxide, diamond and magnesium oxide.
[0012]
Among these, silicon dioxide, aluminum oxide and cerium oxide are preferred, and silicon dioxide is more preferred from the viewpoint of reducing scratches. Specific examples thereof include colloidal silica particles, fumed silica particles, surface-modified silica particles, and the like as silicon dioxide; α-alumina particles, γ-alumina particles, δ-alumina particles, and θ-alumina particles as aluminum oxide. , Η-alumina particles, amorphous alumina particles, fumed alumina, colloidal alumina, etc. of different production methods; cerium oxide having a trivalent or tetravalent oxidation number, a hexagonal crystal system, etc. An axis system or a face-centered cubic system is exemplified.
[0013]
Further, among these, colloidal silica particles are more preferable. Colloidal silica particles are relatively spherical in shape, and can be stably dispersed in the form of primary particles and are less likely to form aggregated particles, so that scratches on the surface to be polished can be reduced. Colloidal silica particles can be obtained by a water glass method using alkali metal silicate such as sodium silicate as a raw material or an alkoxysilane method using tetraethoxysilane or the like as a raw material. These abrasive particles may be used alone or in combination of two or more.
[0014]
The abrasive particles used in Embodiment 1 contain abrasive particles having a particle size of 2 to 200 nm in an amount of 50% by volume or more. The content of the abrasive particles having a particle diameter of 2 to 200 nm is preferably 70% by volume or more, more preferably 85% by volume or more, and particularly preferably 95% by volume or more, from the viewpoint of flattening characteristics and reduction of scratches. , Most preferably 100% by volume.
[0015]
In the first aspect, the polishing particles having a particle diameter of 2 to 200 nm are, in the total amount thereof, 40 to 75% by volume of small particle polishing particles having a particle diameter of less than 2 to 58 nm, and medium particle polishing having a particle diameter of less than 58 to 75 nm. It contains 0 to 50% by volume of particles and 10 to 60% by volume of large abrasive particles having a particle diameter of 75 to 200 nm.
[0016]
The content of the small abrasive particles is preferably 42 to 73% by volume, and more preferably 43 to 72% by volume, from the viewpoint of flattening characteristics. The content of the medium-sized abrasive particles is preferably 0 to 40% by volume, more preferably 0 to 30% by volume, and particularly preferably 0 to 25% by volume from the viewpoint of flattening characteristics. The content of the large-diameter abrasive particles is preferably from 13 to 55% by volume, and more preferably from 15 to 50% by volume, from the viewpoint of flattening characteristics.
[0017]
The particle size distribution of the abrasive particles can be determined by the following method. That is, a photograph obtained by observing the abrasive particles with a transmission electron microscope “JEM-2000FX” (80 kV, 10,000 to 50,000 times) manufactured by JEOL Ltd. is captured as image data by a scanner connected to a personal computer, and analysis software “WinROOF” is used. (Distributor, Mitani Corporation) is used to determine the equivalent circle diameter of each abrasive particle, consider it as the diameter of the abrasive particle, analyze 1000 or more abrasive particle data, and then use that as the basis. The abrasive particle diameter is converted into an abrasive particle volume using spreadsheet software “EXCEL” (manufactured by Microsoft). First, the proportion (% by volume) of abrasive particles of 2 nm to 200 nm (2 to 200 nm) in all the abrasive particles is calculated, and 2 nm to less than 58 nm (2 to 58 nm) of the entire set of abrasive particles of 2 nm to 200 nm. Less than 58 nm, less than 75 nm (58 to less than 75 nm), and 75 nm to 200 nm (75 to 200 nm) (volume%).
[0018]
The abrasive particles used in the aspect 2 preferably contain at least 50% by weight or more, more preferably the total of the abrasive particle group (A) and the abrasive particle group (B), from the viewpoint of flattening characteristics and reduction of scratches. Is 70% by weight or more, more preferably 85% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight.
[0019]
Among the abrasive particles used in the aspect 2, the average particle size of the abrasive particles mixed as the abrasive particle group (A) is from 2 to 50 nm, preferably from 10 to 50 nm, particularly preferably from the viewpoint of improving the polishing rate. 26 to 50 nm. The average particle diameter of the abrasive particles mixed as the abrasive particle group (B) is from 52 to 200 nm or less, preferably from 55 to 170 nm, from the viewpoint of preventing sedimentation and separation of the particles.
[0020]
In the aspect 2, further from the viewpoint of the flattening characteristics, the abrasive particles (Dmin) having the smallest average particle diameter among the abrasive particles mixed as the abrasive particle group (A) are mixed as the abrasive particle group (B). It is preferable that the average particle diameter ratio (Dmax / Dmin) of the abrasive particles having the largest average particle diameter among the abrasive particles (Dmax) exceeds 3. The average particle diameter D (nm) can be calculated as D = 2720 / S from the specific surface area S (m ² / g) obtained by measurement by the nitrogen adsorption method.
[0021]
In the aspect 2, the weight ratio of the abrasive particle group (A) to the abrasive particle group (B) is such that the lower limit is from the viewpoint of flattening characteristics, and the upper limit is the weight ratio of A and B (A / B) from the viewpoint of polishing rate. Is from 0.5 / 1 to 4.5 / 1, preferably from 1.0 / 1 to 4.0 / 1. One or more abrasive particles that can be mixed as the abrasive particle group (A) and the abrasive particle group (B) can be mixed as long as the average particle diameter is within a specified range.
[0022]
In addition, as the abrasive particles used in the present invention, from the viewpoint of efficient polishing for reducing scratches and flattening in a short time, those satisfying both the conditions of the abrasive particles used in aspects 1 and 2, ie, The content of the abrasive particles having a particle size of 2 to 200 nm in the abrasive particles is 50% by volume or more, and the abrasive particles contain 40 to 75% by volume of the small abrasive particles in the total amount of the abrasive particles having a particle size of 2 to 200 nm. Containing 0 to 50% by volume of the entire abrasive particles having a particle diameter of 2 to 200 nm, 10 to 60% by volume of the large abrasive particles in the total amount of the abrasive particles having a particle diameter of 2 to 200 nm, and The weight ratio (A / B) of the abrasive particle group (A) having an average particle diameter of 2 to 50 nm and the abrasive particle group (B) having an average particle diameter of 52 to 200 nm is 0.5 / 1 to 4. 5/1 can be used .
[0023]
In Embodiments 1 and 2, the lower limit of the content of the abrasive particles in the polishing composition is preferably 1 to 50% by weight, and the upper limit is preferably 3 to 40% by weight from the viewpoints of polishing rate and dispersion stability and cost. Is more preferable, and 5 to 30% by weight is particularly preferable.
[0024]
In Embodiments 1 and 2, as the aqueous medium, a mixed medium of water and a solvent miscible with water such as alcohol can be used, but water is preferably used. The amount of the aqueous medium in the polishing composition is preferably from 40 to 99% by weight, more preferably from 50 to 97% by weight, and more preferably from 60 to 95% by weight, from the viewpoint of dispersion stability at the lower limit and the polishing rate at the upper limit. % Is particularly preferred.
[0025]
The polishing composition of Embodiments 1 and 2 contains the aqueous medium and abrasive particles. The polishing composition containing such polishing particles can be prepared, for example, by the following method. A method in which the particles are mixed in an aqueous medium and, for example, powdered abrasive particles are further pulverized as necessary, and forcibly dispersed by mechanical force such as ultrasonic waves, stirring, and kneading. A method of growing particles in an aqueous medium used for inorganic particles. Among them, the method of growing inorganic particles in an aqueous medium is preferable because the obtained inorganic particles are stably dispersed and the control of the particle size is easy.
[0026]
Various additives can be added to the polishing composition of Embodiments 1 and 2 as needed. Examples of the additive include a pH adjuster, a dispersion stabilizer, an oxidizing agent, a chelating agent, a preservative, and the like.
[0027]
As pH adjusters, ammonia, potassium hydroxide, sodium hydroxide, basic substances such as water-soluble organic amines, acetic acid, oxalic acid, succinic acid, glycolic acid, malic acid, citric acid, organic acids such as benzoic acid and And acidic substances such as inorganic acids such as nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid. In addition, oxalic acid and succinic acid can also be used as a chelating agent.
[0028]
Examples of the dispersion stabilizer include surfactants such as anionic surfactants, cationic surfactants, and nonionic surfactants, or polyacrylic acid or a salt thereof, an acrylic acid copolymer, ethylene oxide-propylene oxide. Polymer dispersants such as block copolymers (pluronics) and the like.
[0029]
Examples of the oxidizing agent include peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, nitric acid or a salt thereof, peroxoacid or a salt thereof, oxyacid or a salt thereof, metal salts, and sulfuric acid.
[0030]
Examples of the chelating agent include polycarboxylic acids such as oxalic acid, succinic acid, phthalic acid, and trimellitic acid; hydroxycarboxylic acids such as glycolic acid, malic acid, citric acid, and salicylic acid; and polyaminocarboxylic acids such as nitrilotriacetic acid and ethylenediaminetetraacetic acid. Acid; phosphonic acids such as aminotri (methylenephosphonic acid) and 1-hydroxyethylidene-1,1-diphosphonic acid;
[0031]
Preservatives include benzalkonium chloride, benzethonium chloride, 1,2-benzisothiazolin-3-one, and the like.
[0032]
It is preferable that the pH of the polishing composition of Embodiments 1 and 2 is appropriately determined depending on the type of the object to be polished, required quality, and the like. For example, the pH of the polishing composition is preferably from 2 to 12 from the viewpoints of the cleaning property of the object to be polished, the corrosion prevention property of the processing machine, and the safety of the operator. When the object to be polished is used for polishing a semiconductor wafer, a semiconductor element, and the like, particularly for polishing a silicon substrate, a polysilicon substrate, a silicon oxide film, and the like, from the viewpoint of improving the polishing rate and the surface quality, 7 to 12 are preferable. More preferably, 8-12 are more preferable, and 9-12 are particularly preferable. The pH can be adjusted by adding a desired amount of the above-mentioned pH adjuster as needed.
[0033]
The polishing method of the present invention uses a polishing liquid prepared by using the polishing liquid composition of the above aspect 1 or 2, or by mixing respective components so as to have a composition of the polishing liquid composition of the aspect 1 or 2. Refers to one having a step of polishing the surface to be polished, whereby a substrate for precision parts can be particularly suitably manufactured. Therefore, the present invention relates to a method for manufacturing a semiconductor device.
[0034]
The material of the object to be polished, which is the object of the present invention, is, for example, a metal or semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, and an alloy containing these metals as a main component, glass, or glassy. Glass materials such as carbon and amorphous carbon; ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, titanium nitride, and polysilicon; and resins such as polyimide resins. In particular, when polishing a substrate having silicon dioxide on a surface to be polished, such as glass or a TEOS film, or a substrate having polysilicon, the polishing composition of Embodiment 1 or 2 (hereinafter referred to as the polishing composition of the present invention) Is used, flattening can be efficiently realized.
[0035]
There is no particular limitation on the shape of the object to be polished. For example, the polishing liquid of the present invention may have a shape having a flat portion such as a disk, a plate, a slab, or a prism, or a shape having a curved portion such as a lens. It is an object of polishing using the composition. Among them, it is suitable for polishing a disk-shaped object to be polished, and is particularly suitable for polishing for the purpose of flattening a semiconductor substrate having irregularities. Accordingly, the present invention relates to a method for planarizing a semiconductor substrate.
[0036]
In the surface to be polished having the unevenness according to the present invention, the unevenness step is preferably 100 to 20000 (10 to 2000 nm), more preferably 1000 to 15000 (100 to 1500 nm). Here, the unevenness step can be obtained by a profile measuring device (for example, HRP-100 manufactured by KLA-Tencor).
[0037]
Polishing of a semiconductor substrate includes polishing performed in a polishing step of a silicon wafer (bare wafer), a step of forming a buried element isolation film, a step of flattening an interlayer insulating film, a step of forming a buried metal wiring, a step of forming a buried capacitor, and the like. In particular, it is suitable for a step of forming a buried element isolation film and a step of flattening an interlayer insulating film.
[0038]
The polishing method using the polishing composition of the present invention is not particularly limited, and a general method can be used. Among them, a polishing apparatus provided with a jig for holding an object to be polished and a polishing cloth is preferably used. As the polishing cloth, a jig for holding the object to be polished is pressed against a polishing plate on which an organic polymer foam, a non-foamed body, a non-woven polishing cloth or the like is stuck, or a polishing cloth stuck with a polishing cloth. A method of sandwiching the above-described object to be polished, supplying the polishing composition of the present invention to the surface of the object to be polished, and polishing the surface of the object to be polished by moving the polishing plate or the object to be polished while applying a constant pressure. Is mentioned.
[0039]
Further, the method for manufacturing a semiconductor device of the present invention includes a film forming step of forming a thin film above a semiconductor substrate having irregularities, and a polishing step of polishing the thin film. Supplying the polishing composition of the present invention to the surface of the thin film, and flattening the surface of the thin film having irregularities by CMP, such as a memory IC, a logic IC, or a system LSI. It is suitably used for manufacturing semiconductor devices.
[0040]
As described above, the polishing liquid composition of the present invention, a polishing method using the same, and a method for manufacturing a semiconductor device having a step of polishing a semiconductor substrate using the same can efficiently realize planarization. Become.
[0041]
【Example】
Examples 1 to 5 and Comparative Examples 1 to 4
The silica particles shown in Table 1 were used as the abrasive particles.
[0042]
[Table 1]

[0043]
In order to obtain the polishing composition of the present invention, a polishing composition having the polishing particle concentrations shown in Tables 2 and 3 (the remainder being water) was prepared using the silica particles and water shown in Table 1. Further, the pH was adjusted with an aqueous potassium hydroxide solution so as to be 10.5 to 11.5. The polishing particle concentration described in Table 2 was determined by the following polishing apparatus conditions and polishing rate measuring method so that the polishing rate was about 2300 (Å / min) [230 nm / min].
[0044]
<Polishing equipment conditions>
Polishing tester: LP-541 made by Lapmaster SFT (platen diameter 540mm)
Polishing pad: IC-1000 / Suba400 manufactured by Rodale Nitta
Platen rotation speed: 60 rpm
Carrier rotation speed: 58 rpm
Polishing liquid flow rate: 200 (g / min)
Polishing load: 300 (g / cm ² )
[0045]
<Polishing rate measuring method>
A 2 μm PE-TEOS film formed on an 8 inch (200 mm) silicon substrate was polished as a material to be polished, and polished for 2 minutes under the above set conditions, and the polishing rate (nm / nm) was determined from the difference in the remaining film thickness before and after the polishing. min). The residual film thickness was measured using an optical interference type film thickness meter (VM-1000, Dainippon Screen Mfg. Co., Ltd.).
[0046]
In order to evaluate the flattening characteristics, a commercially available wafer for evaluating the CMP characteristics (trade name: SKW7-2, manufactured by SKW Associates, Inc .: unevenness 8000 ° (800 nm)) is used as the material to be polished. The evaluation was made based on the time until the uneven steps on the wafer formed beforehand were eliminated by polishing. Specifically, the residual film thickness of the convex and concave portions of the GRADUAL D90 pattern on the wafer (measurement method is the same as above) is measured every one minute polishing under the above set conditions, and it is known from the known initial step. The required polishing time was measured by repeating this process until the possible uneven step amount became zero (the planarization was completed). The results are expressed as the polishing time until the completion of the flattening, and 4 minutes or less are judged to be good (Table 2). This indicates that the flattening characteristics of Examples 1 to 5 are better than those of Comparative Examples 1 to 4, even though the polishing rates of the respective polishing liquids are all prescribed to be 230 nm / min.
[0047]
[Table 2]

[0048]
[Table 3]

[0049]
【The invention's effect】
The polishing composition of the present invention is capable of efficiently planarizing a polished surface to be polished. By using the polishing composition, and by polishing using the polishing composition. It is possible to provide a method and a method for manufacturing a semiconductor device having a step of polishing a semiconductor substrate using the method.

Claims

A polishing composition comprising an aqueous medium and polishing particles, wherein the content of the polishing particles having a particle size of 2 to 200 nm in the polishing particles is 50% by volume or more, and the particle size of the polishing particles is 2 to 58 nm. The abrasive particles having a small particle diameter of less than 40 to 75% by volume based on the total amount of the abrasive particles having a particle diameter of 2 to 200 nm, and the abrasive particles having a particle diameter of less than 58 to 75 nm are contained in the total amount of the abrasive particles having a particle diameter of 2 to 200 nm. A polishing composition containing 0 to 50% by volume, and 10 to 60% by volume of large abrasive particles having a particle diameter of 75 to 200 nm in the total amount of the abrasive particles having a particle diameter of 2 to 200 nm.

A polishing liquid composition comprising an aqueous medium and abrasive particles, wherein the abrasive particles have an average particle diameter of 2 to 50 nm (A), and the abrasive particles have an average particle diameter of 52 to 200 nm ( B), wherein the weight ratio (A / B) of A and B is 0.5 / 1 to 4.5 / 1.

3. The polishing composition according to claim 1, wherein the surface to be polished is a surface of a semiconductor substrate.

The polishing composition according to any one of claims 1 to 3, wherein the abrasive particles are silicon dioxide.

A polishing method for planarizing a semiconductor substrate using the polishing composition according to claim 1.

A method for planarizing a semiconductor substrate, comprising using the polishing composition according to claim 1.

A method for manufacturing a semiconductor device, comprising a step of polishing a semiconductor substrate using the polishing composition according to claim 1.