JP2004247542A - Method for manufacturing substrate for precision component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of highly flattening a substrate for a precision component. <P>SOLUTION: The flattening method comprises a 1st process for polishing the substrate by polishing load of 50-1,000 hPa (P1), by using a 1st polishing solution composition containing silica particles, polymer particles and a cation compound in an aqueous medium; and a 2nd process for polishing the substrate by polishing load of 50-1,000 hPa (P2), by using a 2nd polishing solution composition containing silica particles in the aqueous medium. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００４０】
［式中、Ｒ_１ 、Ｒ_２ 、Ｒ_３ 及びＲ_４ は独立して炭素数１〜８の脂肪族アルキル基、フェニル基、ベンジル基又は炭素数１〜３のアルカノール基、Ｘ⁻ は一価の陰イオンを示す。］
【００４１】
式（Ｉ）において、Ｒ_１ 、Ｒ_２ 、Ｒ_３ 及びＲ_４ は、炭素数１〜８の脂肪族アルキル基、フェニル基、ベンジル基又は炭素数１〜３のアルカノール基であり、水溶性の観点から、脂肪族アルキル基は、１〜６が好ましく、１〜４がより好ましく、１〜２がさらに好ましい。また、Ｘ⁻ は一価の陰イオンであり、ＯＨ⁻ 、Ｆ⁻ 、Ｃｌ⁻ 、Ｂｒ⁻ 、Ｉ⁻ 、ＮＯ_３ ⁻ 、ＨＳＯ_４ ⁻ 、ＣＨ_３ ＳＯ_３ ⁻ 、Ｈ_２ ＰＯ_４ ⁻ 、ＨＣＯＯ⁻ 、ＣＨ_３ ＣＯＯ⁻ 、ＣＨ_３ ＣＨ（ＯＨ）ＣＯＯ⁻ 、Ｃ_２ Ｈ_５ ＣＯＯ⁻ 等が挙げられるが、半導体基板の研磨に用いる場合、ＯＨ⁻ 、ＣＨ_３ ＣＯＯ⁻ 、ＨＣＯＯ⁻ が好ましい。式（Ｉ）で表される四級アンモニウム塩化合物の具体的な例としては、テトラメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、テトラエチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、テトラプロピルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、テトラブチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、エチルトリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、プロピルトリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、ブチルトリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、Ｎ−ヒドロキシエチル−Ｎ，Ｎ，Ｎ−トリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、Ｎ−ヒドロキシプロピル−Ｎ，Ｎ，Ｎ−トリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、Ｎ−ヒドロキシエチル−Ｎ−ヒドロキシプロピル−Ｎ，Ｎ−ジメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、フェニルトリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、ベンジルトリメチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、ベンジルトリエチルアンモニウム塩（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）等が挙げられる。
【００４２】
【化２】

【００４３】
［式中、Ｒ_５ 、Ｒ_６ 、Ｒ_７ 、Ｒ_８ 、Ｒ_９ 及びＲ_１０は独立して炭素数１〜８の脂肪族アルキル基、フェニル基、ベンジル基又は炭素数１〜３のアルカノール基、Ｘ⁻ は一価の陰イオン、ｎは１〜１２の整数を示す。］
【００４４】
式（ＩＩ）において、Ｒ_５ 、Ｒ_６ 、Ｒ_７ 、Ｒ_８ 、Ｒ_９ 及びＲ_１０は、炭素数１〜８の脂肪族アルキル基、フェニル基、ベンジル基又は炭素数１〜３のアルカノール基であり、水溶性の観点から、脂肪族アルキル基は、１〜６が好ましく、１〜４がより好ましく、１〜２がさらに好ましい。また、Ｘ⁻ は一価の陰イオンであり、ＯＨ⁻ 、Ｆ⁻ 、Ｃｌ⁻ 、Ｂｒ⁻ 、Ｉ⁻ 、ＮＯ_３ ⁻ 、ＨＳＯ_４ ⁻ 、ＣＨ_３ ＳＯ_３ ⁻ 、Ｈ_２ ＰＯ_４ ⁻ 、ＨＣＯＯ⁻ 、ＣＨ_３ ＣＯＯ⁻ 、ＣＨ_３ ＣＨ（ＯＨ）ＣＯＯ⁻ 、Ｃ_２ Ｈ_５ ＣＯＯ⁻ 等が挙げられるが、半導体基板の研磨に用いる場合、ＯＨ⁻ 、ＣＨ_３ ＣＯＯ⁻ 及びＨＣＯＯ⁻ が好ましく、ｎは１〜１２の整数であり、配合性の観点から、１〜８が好ましく、１〜６がより好ましい。式（ＩＩ）で表される四級アンモニウム塩系化合物の具体的な例としては、Ｎ，Ｎ’−テトラメチレンビス（トリメチルアンモニウム塩）（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、Ｎ，Ｎ’−ペンタメチレンビス（トリメチルアンモニウム塩）（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）、Ｎ，Ｎ’−ヘキサメチレンビス（トリメチルアンモニウム塩）（ハイドロオキサイド、クロライド、ブロマイド、アセテート、ホルメート）等が挙げられる。
【００４５】
ベタイン化合物としては、水溶性の観点から炭素数１〜２０のものが好ましく、１〜１０がより好ましく、１〜６がさらに好ましく、１〜４が特に好ましい。
具体的には、トリメチルグリシン等の酢酸ベタイン、トリメチルアミノプロピオン酸ベタイン等のβ−Ｎ−アルキルアミノプロピオン酸、２−メチル−Ｎ−カルボキシメチル−Ｎ−ヒドロキシエチルイミダゾリニウムベタイン等のイミダゾリンカルボン酸、２−ヒドロキシ−３−スルホプロピルトリメチルベタイン等のスルホベタイン等が挙げられる。
【００４６】
アミノ酸化合物としては、水溶性の観点から水溶性の観点から炭素数１〜２０のものが好ましく、１〜１５がより好ましく、１〜１０がさらに好ましく、１〜６が特に好ましい。具体的には、グリシン、アラニン、セリン、トリプトファン、グルタミン、リシン、アルギニン等のα−アミノ酸、β−アラニン等のβ−アミノ酸、γ−アミノ酪酸等のγ−アミノ酸が挙げられる。
【００４７】
これらの中で、さらに好ましくは、水溶性の観点、平坦化特性の観点から、プロピルアミン、イソプロピルアミン、ブチルアミン、ヘキサメチレンジアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルヘキサメチレンジアミン、ジエチレントリアミン、ビス（３−アミノプロピル）アミン、テトラメチルアンモニウム塩、Ｎ−ヒドロキシプロピル−Ｎ，Ｎ，Ｎ−トリメチルアンモニウム塩、Ｎ−ヒドロキシエチル−Ｎ−ヒドロキシプロピル−Ｎ，Ｎ−ジメチルアンモニウム塩、Ｎ，Ｎ’−ヘキサメチレンビス（トリメチルアンモニウム塩）、アルギニン等である。
【００４８】
第１の研磨液組成物において使用できるシリカ粒子としては、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が挙げられる。表面修飾したシリカ粒子等とは、アルミニウム、チタン、ジルコニウム等の金属やそれらの酸化物を直接あるいはカップリング剤を介して、シリカ粒子表面に吸着及び／又は結合させたものや、シランカップリング剤やチタンカップリング剤などを結合させたものを指す。
【００４９】
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し、水溶液中で縮合反応させシリカ粒子を成長させる水ガラス法、又はテトラエトキシシラン等を原料とし、アルコール等の水溶性有機溶媒含有水中で縮合反応させシリカ粒子を成長させるアルコキシシラン法で得ることができる。フュームドシリカ粒子は、四塩化珪素等の揮発性珪素化合物を原料とし、酸水素バーナーによる１０００℃以上の高温下で気相加水分解する方法で得ることができる。これらのシリカ粒子は、単独で又は２種以上を混合して用いてもよい。
【００５０】
コロイダルシリカ粒子の平均粒径は、研磨速度の観点、また、沈降・分離を防止する観点から、５〜５００ｎｍが好ましく、１０〜３００ｎｍがより好ましく、２０〜２００ｎｍが更に好ましい。なお、コロイダルシリカ粒子の平均粒子径は、ＢＥＴ法で測定した比表面積を用いて、算出した一次粒子の平均粒径である。なお、ＢＥＴ法より求める粒子径（ｎｍ）は、２７２０／比表面積｛比表面積（ｍ^２ ／ｇ）｝の式により算出される。
【００５１】
ヒュームドシリカ粒子の平均粒径は、研磨速度の観点、また、沈降・分離を防止する観点から、２０〜２０００ｎｍが好ましく、３０〜１０００ｎｍがより好ましく、４０〜８００ｎｍが更に好ましい。なおヒュームドシリカの平均粒子径は、ヒュームドシリカが二次凝集しているため、光散乱法又は光回折法で測定される二次粒子の平均粒子径である。
【００５２】
第１の研磨液組成物において使用できる水系媒体としては、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が挙げられるが、イオン交換水等の水を用いることが好ましい。
【００５３】
第１の研磨液組成物は、シリカ粒子、重合体粒子及びカチオン性化合物を水系媒体に配合することにより調製することができる。なかでも、配合時におけるシリカ粒子及び重合体粒子の分散安定性の観点から、シリカ粒子を含む水分散体と重合体粒子を含む水分散体とカチオン性化合物を溶解した水溶液とを混合する方法が好ましい。
【００５４】
シリカ粒子を含む水分散体は、例えば、以下の方法によって調製することができる。粉末状のシリカ粒子を、必要に応じてさらに粉砕し、水系媒体中に配合し、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や、水系媒体中でシリカ粒子を成長させる方法を用いることができる。
【００５５】
重合体粒子を含む水分散体は、例えば、以下の方法によって調製することができる。水系媒体を用いて単量体を重合させ、あるいは必要に応じて他の単量体と共重合させ、生成する重合体粒子とそれを含む水系媒体を、そのまま得る方法。
有機溶媒を用いて単量体を重合させ、あるいは必要に応じて他の単量体と共重合させ、生成する重合体粒子とそれを含む有機溶媒を、蒸留等によりそのまま水系媒体に溶媒置換し、水分散体を得る方法。水系媒体あるいは有機溶媒を用いて重合し、得られた重合体を乾燥及び粉砕等を行った後、得られる粉末を水性媒体に再分散させ、水分散体を得る方法。中でも、水系媒体を用いて単量体を重合させ、あるいは必要に応じて他の単量体と共重合させ、生成する重合体粒子とそれを含む水系媒体を、そのまま水分散体として得る方法が、簡便であり、得られる重合体粒子の平均粒径の制御も容易であり好ましい。
【００５６】
第１の研磨液組成物のｐＨは、シリカ粒子と被研磨基板をマイナスに帯電させて、カチオン性化合物による吸着皮膜の形成を促進させる観点から、７〜１３が好ましく、８〜１２がより好ましく、９〜１２がさらに好ましい。
【００５７】
第１の研磨液組成物を上記のｐＨに調整するためにｐＨ調整剤を用いることができる。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、四級アンモニウムハイドロオキサイド等の塩基性物質、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。
【００５８】
第１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、分散安定化剤、防腐剤等が挙げられる。
【００５９】
分散安定化剤としては、アニオン性界面活性剤、カチオン性界面活性剤、ノニオン性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。
【００６０】
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、過酸化水素、次亜塩素酸塩等が挙げられる。
【００６１】
本発明に用いられる第２の研磨液組成物のシリカ粒子の種類及び含有量は、前記の第１の研磨液組成物と同様であればよい。
【００６２】
第２の研磨液組成物において使用できる水系媒体としては、前記の第１の研磨液組成物と同様であればよい。また、第２の研磨液組成物中の水系媒体含有量は、下限は沈降・分離を防止する観点から、上限は研磨速度向上の観点から、５０〜９９重量％が好ましく、６０〜９７重量％がより好ましい。
【００６３】
第２の研磨液組成物は、シリカ粒子を水系媒体に配合することにより調製することができる。粉末状のシリカ粒子を、必要に応じてさらに粉砕し、水系媒体中に配合し、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や、水系媒体中でシリカ粒子を成長させる方法を用いることができる。
【００６４】
第２の研磨液組成物には、必要に応じて重合体粒子及び／又はカチオン性化合物を配合することができる。その場合、第２の研磨液組成物中の重合体粒子含有量は、過度の研磨速度向上を避け、研磨終了時期を容易に管理する観点から、好ましくは１重量％以下、より好ましくは０．５重量％以下、さらに好ましくは０．１重量％未満、特に好ましくは０．０５重量％以下である。また、第２の研磨液組成物中のカチオン性化合物含有量は、目的とする研磨位置まで研磨するために必要な研磨速度を確保する観点から、好ましくは０．１重量％以下、より好ましくは０．０５重量％以下、さらに好ましくは０．０１重量％未満、特に好ましくは０．００５重量％以下である。第２の研磨液組成物の調製は、中でも前記２成分を併用する場合、前記の第１の研磨液組成物と同様であればよい。
【００６５】
また、第２の研磨液組成物のｐＨは、アルカリによるエッチング作用に基づく研磨速度の向上の点から、前記の第１の研磨液組成物と同様であり、第２の研磨液組成物を上記のｐＨに調整するためにｐＨ調整剤を用いることができる。ｐＨ調整剤としては、前記の第１の研磨液組成物と同様であればよい。
【００６６】
第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。これらは前記の第１の研磨液組成物と同様であればよい。
【００６７】
本発明の精密部品用基板の製造方法が適用される被研磨面の材質は、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、熱酸化膜、ＴＥＯＳ膜、ＢＰＳＧ膜、窒化ケイ素膜あるいはポリシリコン膜等の被研磨面にケイ素を含む膜が形成された精密部品用基板、例えば半導体基板を研磨する際に、効率的に平坦化が実現できる。
【００６８】
本発明の精密部品用基板の製造方法は、精密部品用基板の一種である半導体基板の被研磨面を研磨して平坦化する工程に用いることができ、例えばシリコンウェハ（ベアウェハ）のポリッシング工程、埋め込み素子分離膜形成工程、層間絶縁膜平坦化工程、埋め込み金属配線形成工程、埋め込みキャパシタ形成工程等がある。本発明は、特に埋め込み素子分離膜形成工程、層間絶縁膜平坦化工程、埋め込みキャパシタ形成工程に適しており、メモリーＩＣ、ロジックＩＣ、あるいはシステムＬＳＩ等の製造に好適に用いられる。従って本発明は、該製造方法により得られた精密部品用基板を用いた半導体装置に関する。
【００６９】
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方法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、特に薄膜が形成され表面に凹凸を有する精密部品用基板を所望の厚さで平坦化する目的で行う研磨に好適である。従って、本発明は、精密部品用基板の平坦化方法に関する。
【００７０】
前記凹凸を有する精密部品用基板の製造方法において、好適である凹凸段差とは、第１工程実施前において１０〜２０００ｎｍの段差量を有するものであり、さらに１００〜１５００ｎｍの段差量を有するものがより好適である。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、商品名：ＨＲＰ−１００）により求めることができる。
【００７１】
本発明の精密部品用基板の製造方法で用いられる研磨装置としては、特に制限はなく、一般的な装置を用いることができる。中でも好ましくは、研磨される基板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。該研磨装置を用いる製造方法の具体例としては、有機高分子系の発泡体、無発泡体及びそれらに重合体粒子等を充填したもの、あるいは不織布状等からなる研磨布を張り付けた研磨盤に、基板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基板を挟み込み、本発明で用いられる研磨液を基板表面に供給し、一定の圧力を加えながら研磨盤や基板を動かすことにより基板表面を研磨する方法が挙げられる。
【００７２】
第１工程と第２工程は、同一研磨布上で連続して実施しても良いし、また第１工程後にリンス工程、ドレッシング工程、バフ研磨工程或いは洗浄工程等を実施した後、第２工程を実施しても良い。さらに第１工程を実施後、必要によりリンス工程、バフ研磨工程或いは洗浄工程等を実施した後、基板を異なる研磨布上に移動させて第２工程を実施しても良い。
【００７３】
研磨液の供給方法は、該研磨液の構成成分が充分に混合された状態で研磨布上に供給される方法が好ましい。具体的には該研磨液の構成成分が予め混合され所定濃度に調製されたものをポンプ等で研磨布上に供給しても良いし、また該構成成分の水分散体或いは水溶液を個別に、又はその一部を混合したプレミックス液を調製し、各々をポンプ等で供給し供給配管内で混合させることによって、研磨布上に所定濃度の研磨液を供給する方法でも良い。供給配管内で混合する場合には、充分に混合できるように供給配管中に撹拌を促進する混合装置を設けることが好ましい。
【００７４】
【実施例】
以下の実施例中の「重量％」は、重合体粒子の水分散体全量又は研磨液組成物全量に対してである。「部」は、重量部を示す。
【００７５】
合成例〔重合体粒子の合成〕
スチレン２７部、５５％ジビニルベンゼン３部、脂肪酸カリウム（花王（株）製、ＫＳソープ）１．５部、イオン交換水６８．５部を２Ｌのセパラブルフラスコに仕込み、フラスコ内を窒素ガスで置換し、６５℃に昇温した。フラスコに０．０６部の過硫酸カリウムを投入し、３時間重合し、重合体粒子の水分散液を得た。光散乱法（大塚電子（株）製、商品名：レーザーゼータ電位計 ＥＬＳ８０００）にて測定した平均粒子径は７１ｎｍであった。
【００７６】
実施例及び比較例
＜研磨液の調製＞
Ｎ−ヒドロキシプロピル−Ｎ，Ｎ，Ｎ−トリメチルアンモニウムホルメート（花王（株）製、商品名：カオーライザーＮｏ．４３０）２．３部にイオン交換水５１部を加え攪拌溶解する。攪拌下、さらに合成例１において得られた重合体粒子の水分散液６．７部（重合体粒子は２部）とコロイダルシリカの水分散液（デュポン製、商品名：Ｓｙｔｏｎ ＯＸ−Ｋ５０、有効分５０％、平均粒子径４０ｎｍ）４０部を加え、さらに必要に応じて、研磨液組成物のｐＨは、１０．５〜１１．５となるよう水酸化カリウム水溶液で調整することによって、実施例に用いる研磨液Ａを得た。
【００７７】
次に、イオン交換水６０部に、コロイダルシリカの水分散液（デュポン製、商品名：Ｓｙｔｏｎ ＯＸ−Ｋ５０、有効分５０％、平均粒子径４０ｎｍ）４０部を加えて撹拌し、さらに必要に応じて、研磨液組成物のｐＨは、１０．５〜１１．５となるよう水酸化カリウム水溶液で調整することによって、実施例に用いる研磨液Ｂを得た。
【００７８】
最後に、イオン交換水４８部に、市販ヒュームドシリカ研磨液（キャボット・マイクロエレクトロニクス・コーポレーション製、商品名：ＳＥＭＩ−ＳＰＥＲＳＥ２５ ）５２部を加えて撹拌し、比較例に用いる研磨液を得た。
このようにして調製した研磨液を用い、以下の条件で研磨実験を行い、評価した。
【００７９】
＜研磨条件＞
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／Ｓｕｂ４００
プラテン回転数：６０ｒｐｍ
キャリア回転数：６１ｒｐｍ
研磨液供給量：２００（ｇ／ｍｉｎ）
研磨荷重：１９６〜４９０（ｈＰａ）
【００８０】
＜研磨速度測定／評価方法＞
１．ブランケットウエハ
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（ブランケットウエハ）を用いて、上記設定条件で２分間研磨し、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）製、商品名：ＶＭ−１０００）を用いた。研磨荷重と研磨速度の関係をプロットし、研磨特性を評価した。
【００８１】
２．パターンウエハ
平坦化特性を評価するために、被研磨材としてＣＭＰ特性評価用市販ウエハ（パターンウエハ、商品名：ＳＫＷ７−２、ＳＫＷアソシエーテス社（ＳＫＷ Ａｓｓｏｃｉａｔｅｓ，Ｉｎｃ．） 製：凹凸段差８００ｎｍ）を用いて、予め形成されたウエハの凹凸段差が研磨により平坦化される過程を測定し評価を行った。具体的には、まず研磨開始前にウエハ上のＧＲＡＤＵＡＬ Ｄ１０，Ｄ５０，Ｄ９０ パターン（Ｄ１０ ：凸部幅１０μｍ ／凹部幅９０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン、Ｄ５０ ：凸部幅５０μｍ ／凹部幅５０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン、Ｄ９０ ：凸部幅９０μｍ ／凹部幅１０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン）の図２に示す初期表面段差５（測定方法は前述）、初期凸部膜厚３と初期凹部膜厚４（測定方法は前述）を測定し、基板段差２を算出する（基板段差２＝初期表面段差５＋初期凹部膜厚４−初期凸部膜厚３）。続いて上記設定条件で１分毎にウエハ上のＧＲＡＤＵＡＬ Ｄ１０，Ｄ５０，Ｄ９０ パターン（Ｄ１０ ：凸部幅１０μｍ ／凹部幅９０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン、Ｄ５０ ：凸部幅５０μｍ ／凹部幅５０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン、Ｄ９０ ：凸部幅９０μｍ ／凹部幅１０μｍ のＬｉｎｅ＆Ｓｐａｃｅパターン）の凸部と凹部の残存膜厚（測定方法は前述）を測定し、これらから図２に示す凸部、凹部の基準面１からの高さに相当する（凸部残存膜厚８＋基板段差２）及び凹部残存膜厚９の値を研磨時間に対してプロットし、平坦化特性及びパターン依存性を評価した。
【００８２】
＜ブランケットウエハの研磨結果＞
実施例の研磨液Ａ及びＢを用いて行ったブランケットウエハの研磨において、研磨荷重と研磨速度との関係をそれぞれ図３、図４に示す。まず図３より研磨液Ａは比較例と比べて、低荷重（１９６ ｈＰａ） では研磨速度が抑制され、一方高荷重（４９０ ｈＰａ ）では研磨速度が向上しており、研磨速度の屈曲点が得られていることがわかる。次に図４より研磨液Ｂは比較例と類似の研磨特性であり、研磨速度の屈曲点を示さないことがわかる。
【００８３】
＜パターンウエハの研磨結果＞
実施例は研磨液Ａを用いた第１工程を３分間、続いて研磨液Ｂを用いた第２工程を１分間、合計４分間研磨を行った。一方比較例は４分間研磨を行った。どちらも研磨荷重を２９４ｈＰａ とした。
【００８４】
研磨の進行に従って、凸部と凹部の基準面に対する高さと段差が変化し、平坦化に至る過程を図５から図８に示す。実施例、比較例ともに研磨１分後（図５）まではほぼ同等に進行するが、研磨２分後（図６）に至ると比較例においてパターン間、特にＤ１０とＤ９０との間に高さのばらつきが目立ち初め、新たにパターン間の段差が生じて始めていることがわかる。一方実施例ではパターン間の高さのばらつきは比較的少ない。
【００８５】
更に研磨３分後（図７）において、比較例はパターン間の高さのばらつきに加えて、研磨が進行し続けるために過剰な研磨が目立ち、特にＤ１０の高さが目立って減少している。一方実施例は段差の低下とともに研磨が進行しなくなることで過剰な研磨が抑制されており、またパターン間の高さのばらつきも少ない状態を維持している。実施例は、ここで研磨液Ｂに変更して第２工程に移行する。
【００８６】
最後に、実施例の第２工程１分後（図８）（比較例は４分後）では、比較例は各パターンにおける平坦化は完了しているものの、パターン間の高さが大きく異なり、パターン間に新たな段差を残し高度な平坦化が不完全であることがわかる。
【００８７】
一方、実施例は、比較例と同じ合計４分間の研磨によって、パターン内、パターン間を問わず平坦化が為されており、高度な平坦化が実現されていることがわかる。また、実施例においては、過剰な研磨がなされておらず、十分な厚みを有する被研磨層が保存されているため、後工程において処理することで、様々な厚さのパターンに研磨できることがわかる。
【００８８】
【発明の効果】
本発明の精密部品用基板の製造方法を用いることにより、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、或いは埋め込みキャパシタ形成等を行うＣＭＰ技術において、薄膜が形成され表面に凹凸を有する基板であっても高度に平坦化することできるため、高度に平坦化された精密部品用基板、中でも薄膜が形成された表面を有しかつ所望の厚みを有する精密部品用基板を効率よく製造することができるという効果が奏される。
【図面の簡単な説明】
【図１】図１は、本発明の研磨液組成物と通常のシリカ系研磨液とを用いて凹凸パターンを持たない被研磨物を研磨した場合の研磨荷重に対する研磨速度の変化を示す概略図である。
【図２】図２は、実施例で行われたパターンウエハの研磨結果の評価を行う際に測定するパターンウエハの各部位を示す概略図である。
【図３】図３は、実施例で得られた研磨液Ａ及び比較例で得られた研磨液を用いてブランケットウエハを研磨した場合の研磨荷重に対する研磨速度の変化を示す概略図である。
【図４】図４は、実施例で得られた研磨液Ｂ及び比較例で得られた研磨液を用いてブランケットウエハを研磨した場合の研磨荷重に対する研磨速度の変化を示す概略図である。
【図５】図５は、実施例及び比較例において行った研磨１分後の凸部と凹部の基準面に対する高さと段差の変化を示すグラフである。なお、実施例では、第１研磨工程１分後を示す。
【図６】図６は、実施例及び比較例において行った研磨２分後の凸部と凹部の基準面に対する高さと段差の変化を示すグラフである。なお、実施例では、第１研磨工程２分後を示す。
【図７】図７は、実施例及び比較例において行った研磨３分後の凸部と凹部の基準面に対する高さと段差の変化を示すグラフである。なお、実施例では、第１研磨工程３分後を示す。
【図８】図８は、実施例及び比較例において行った研磨４分後の凸部と凹部の基準面に対する高さと段差の変化を示すグラフである。なお、実施例では、第２研磨工程１分後を示す。
【符号の説明】
１ 基準面
２ 基板段差
３ 初期凸部膜厚
４ 初期凹部膜厚
５ 初期表面段差
６ シリコン基板
７ ＴＥＯＳ膜
８ 凸部残存膜厚
９ 凹部残存膜厚[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a precision component substrate, a semiconductor device using the precision component substrate obtained by the manufacturing method, and a method for flattening the precision component substrate. More specifically, the present invention particularly relates to a method for manufacturing a precision component substrate having a thin film formed thereon and having irregularities on the surface, a semiconductor device using the precision component substrate obtained by the manufacturing method, and planarization of the precision component substrate. It is about the method.
[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]
2. Description of the Related Art Conventionally, in a manufacturing process of a semiconductor device, insulation of silicon dioxide or the like formed on a substrate by a method such as plasma-CVD, high-density plasma-CVD, low-pressure-CVD, sputtering, SOD (Spin-On Dielectrics), or electroplating. In order to form a film, a capacitor ferroelectric film, a wiring metal or a metal alloy, and to form a buried layer, there is a CMP method using fumed silica or an alumina-based polishing liquid. However, in such a method, the polishing rate greatly differs due to a local difference in the density or size of the pattern, so-called pattern dependence appears strongly. Therefore, although it can be locally flattened, it can be applied over the entire polished surface of the substrate. Therefore, there is a problem that flattening cannot be realized (that is, advanced flattening cannot be achieved). Therefore, a technique of adding an etch-back step of previously removing a film to be polished on a convex portion by etching has been widely used, but there is a problem that the number of steps is increased and the manufacturing cost is increased.
[0004]
Patent Document 1 discloses that an inorganic oxide abrasive is used as an abrasive, and a water-soluble organic polymer, a water-soluble anionic surfactant, a water-soluble nonionic surfactant, and a water-soluble amine are used as the abrasive. There is disclosed a polishing method for performing flattening by adding Si. However, when silicon oxide particles, that is, silica particles are used as abrasive grains, and a water-soluble organic polymer is used as an additive as described in Patent Document 1, compared with the case where the polymer particles of the present invention are dispersed. Thus, the effect of improving the polishing rate is poor or rather the polishing rate is reduced, so that it is not possible to quickly planarize the surface. In addition, the invention described in Patent Document 1 mainly focuses on using cerium oxide as abrasive grains, and there is no specific working description about silica particles which are considered to cause less scratching.
[0005]
Patent Document 2 discloses a chemical mechanical polishing aqueous dispersion containing polymer particles and inorganic particles and a method for manufacturing a semiconductor device using the dispersion. However, according to the dispersion, the polishing rate is reduced. Although improved, a high degree of planarization is not achieved.
[0006]
[Patent Document 1]
JP 2000-195832 A
[Patent Document 2]
JP 2000-204353 A
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a highly planarized precision component substrate, especially a thin film, in a CMP technique for performing buried element isolation, flattening an interlayer insulating film, forming a buried metal wiring, forming a plug, or forming a buried capacitor. A method for efficiently manufacturing a precision component substrate having a formed surface and a desired thickness, a semiconductor device using the substrate obtained by the manufacturing method, and a substrate having a desired thickness, particularly a thin film are formed. It is an object of the present invention to provide a method for flattening a precision component substrate which can highly planarize even a substrate having an uneven surface.
[0008]
[Means for Solving the Problems]
The gist of the present invention is:
[1] A method for manufacturing a precision component substrate having the following first step and second step,
First step: a step of performing polishing with a polishing load of 50 to 1000 hPa (P1) using a first polishing composition containing silica particles, polymer particles and a cationic compound in an aqueous medium.
Second step: a step of performing polishing with a polishing load of 50 to 1000 hPa (P2) using a second polishing composition containing silica particles in an aqueous medium.
[2] A semiconductor device using the precision component substrate obtained by the manufacturing method according to [1], and
[3] A method for flattening a substrate for precision parts having the following first and second steps:
First step: a step of performing polishing at a polishing load of 50 to 1000 hPa (P1) using a first polishing composition containing silica particles, polymer particles and a cationic compound in an aqueous medium,
Second step: This step relates to a step of performing polishing with a polishing load of 50 to 1000 hPa (P2) using a second polishing composition containing silica particles in an aqueous medium.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to a method for producing a substrate for precision parts, wherein a first polishing liquid composition containing silica particles, polymer particles and a cationic compound is used in an aqueous medium as a first step. The surface to be polished of the substrate is polished with a polishing load of 50 to 1000 hPa (P1).
[0010]
When the first polishing composition is used for polishing an object to be polished which does not have an uneven pattern on the surface to be polished, the polishing rate is suppressed to be low in a region where the polishing load is low, and is high in a region where the polishing load is high. And exhibit polishing characteristics in which the polishing rate greatly depends on the polishing load. On the other hand, with a normal silica-based polishing liquid, the polishing rate has polishing characteristics substantially proportional to the polishing load (see FIG. 1).
[0011]
Although the reason why the first polishing composition exhibits such polishing characteristics is not clear, it is considered that silica particles, polymer particles and a cationic compound coexist. First, in a low load region, that is, under a weak shearing force, the polymer particles maintain a stable dispersion state, so that there is almost no interaction with the abrasive grains. On the other hand, the cationic compound contained in the first polishing composition forms an adsorption film on the surface of the negatively charged silica particles and the surface to be polished, and inhibits the action of the silica particles and the surface to be polished. Therefore, the polishing rate is reduced mainly due to the adsorption film action of the cationic compound.
[0012]
However, in a high load range, the polymer particles are subjected to strong shearing force, so that the polymer particles are aggregated while involving the silica particles, and aggregated composite particles having a strong polishing force are generated. On the other hand, the cationic compound forms an adsorbing film regardless of the strength of the shearing force. However, since the strong abrasive force by the aggregated composite particles acts, the adsorbing film is broken and the polishing rate increases. Therefore, as a result, it is estimated that the polishing rate exhibits polishing characteristics that largely depend on the polishing load.
[0013]
When polishing the surface to be polished having irregularities with the first polishing composition, the polishing load P1 is, for example, as shown in FIG. 1, the slope of the polishing characteristic line of the polishing liquid used in the present invention (polishing load). The polishing rate is set to be close to the largest change in the polishing rate per unit area, so that the convex portion locally has a higher polishing rate corresponding to a polishing load of P1 or more as compared with a normal silica-based polishing liquid containing only silica particles. On the contrary, since the concave portion is locally polished at a low polishing rate corresponding to the polishing load of P1 or less, only the convex portion is selectively polished, and the reduction of the uneven step proceeds efficiently. . Further, as the polishing progresses, the local polishing load applied to the projections and the depressions approaches the polishing load P1 as the unevenness level decreases, so that the polishing rate of both the projections and the depressions decreases, and the polishing almost proceeds after the unevenness level is eliminated. It shows a characteristic polishing characteristic that it no longer occurs. With a normal silica-based polishing liquid, when polishing a substrate on which a pattern in which the unevenness density or unevenness size of the surface to be polished is mixed is polished, the so-called pattern dependency occurs because the polishing proceeds in the recesses as well as the protrusions. Cheap. In the first polishing composition of the present invention, polishing hardly proceeds after the unevenness level difference is eliminated, and as a result, an excellent effect that a high level of flatness with little pattern dependency can be quickly achieved with a small polishing amount is exhibited. Let it.
[0014]
Further, in the present invention, after the first step is completed, or after performing other steps as necessary, as a second step, using a second polishing composition containing silica particles in an aqueous medium, By polishing the surface to be polished of the substrate with a polishing load of 50 to 1000 hPa (P2), the polishing rate, which has been reduced at the end of the first step, can be increased again, and the polishing can be performed to a target polishing position. Since the flattening with little pattern dependency is substantially achieved in the first step, an effect that the entire polishing surface of the substrate can be easily and uniformly polished to the target polishing position is exhibited.
[0015]
Therefore, in the present invention, by performing the polishing process in combination of the first step and the second step, for example, the buried element isolation, the planarization of the interlayer insulating film, the formation of the buried metal wiring, the formation of the plug, or the formation of the buried capacitor In the CMP technique for performing polishing, etc., it is possible to uniformly polish the entire surface to be polished of the substrate to a desired position such as a stopper film, so that the substrate has a highly planarized substrate, especially a surface on which a thin film is formed. In addition, an excellent effect that a precision component substrate having a desired thickness can be efficiently obtained is exhibited.
[0016]
The upper limit of the polishing load P1 in the first step and the polishing load P2 in the second step are 50 to 1000 hPa, and the lower limit is 50 to 1000 hPa, more preferably 70 to 600 hPa, and 100 to 500 hPa. Is more preferred.
[0017]
The other steps include a rinsing step, a dressing step, a buff polishing step, a cleaning step, and the like.
[0018]
The lower limit of the silica particle content in the first polishing composition used in the present invention is from the viewpoint of polishing rate, and the upper limit is from the viewpoint of dispersion stability and cost, from the viewpoint of dispersion stability and cost. The liquid composition is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, even more preferably 5 to 30% by weight.
[0019]
The content of the polymer particles in the first polishing composition is preferably from 0.1 to 20% by weight, more preferably from 0.2 to 15% by weight, and more preferably from 0.3 to 15% by weight, from the viewpoint of the polishing rate and the flattening characteristics. -10% by weight is more preferred.
[0020]
The lower limit of the cationic compound content in the first polishing composition is preferably from 0.01 to 20% by weight, and the upper limit is preferably from 0.01 to 20% by weight from the viewpoint of the polishing rate. Is more preferable, and 0.1 to 10% by weight is further preferable.
[0021]
The lower limit of the aqueous medium content in the first polishing composition is from 40 to 98 for the first polishing composition, the lower limit being from the viewpoint of preventing sedimentation and separation, and the upper limit being from the viewpoint of improving the polishing rate. 0.85% by weight is preferred, and 60-95% by weight is more preferred.
[0022]
Examples of the polymer particles that can be used in the first polishing composition include particles made of a thermoplastic resin and particles made of a thermosetting resin that are not substantially dissolved in water and can exist as dispersed particles. Examples of the thermoplastic resin include a polystyrene resin, a (meth) acrylic resin, a polyolefin resin, a polyvinyl chloride resin, a rubber-based resin, a polyester resin, a polyamide resin, and a polyacetal resin. Epoxy resins, urethane resins, urea resins, melamine resins are mentioned. As the resin, particles made of a thermoplastic resin are preferable from the viewpoints of polishing rate and flattening characteristics, and particles made of a polystyrene resin and a (meth) acryl resin are particularly preferable.
[0023]
Examples of the polystyrene resin include polystyrene and a styrene-based copolymer. Styrene-based copolymers are copolymers of styrene and various ethylenically unsaturated monomers. Examples of copolymerizable ethylenically unsaturated monomers include acrylic acid, methacrylic acid, itaconic acid, and maleic acid. , Carboxylic acid monomers such as fumaric acid, and methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like (methacrylic acid ester monomers, styrene Sulfonic acid monomers such as sodium sulfonate and acrylamide t-butylsulfonic acid; amino monomers such as dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylamide and vinylpyridine; methacrylamidopropyltrimethylammonium chloride; methacryloyloxyethyl Trimethyl ammonium Crosslinking of quaternary ammonium salt monomers such as muchloride, nonionic monomers such as 2-hydroxyethyl methacrylate and methoxypolyethylene glycol methacrylate, divinylbenzene, ethylene glycol dimethacrylate, ethylene bisacrylamide, trimethylolpropane trimethacrylate, etc. And the like.
[0024]
Examples of the (meth) acrylic resin include poly (methyl) methacrylate, poly (meth) ethyl acrylate, poly (meth) butyl acrylate, poly (meth) acrylate 2-ethylhexyl, and an acrylic copolymer. Can be Examples of the acrylic copolymer include one or more (meth) acrylate monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, and various types of ethylene. It is a copolymer composed of an unsaturated monomer. Examples of the copolymerizable ethylenically unsaturated monomer include the same monomers as in the case of the styrene-based copolymer.
[0025]
In particular, when the polymer particles are made of a polystyrene resin or a (meth) acrylic resin, the polymer particles can be used after being crosslinked. Crosslinking can be performed by appropriately copolymerizing the copolymerizable crosslinkable monomer. The degree of this cross-linking is represented by the degree of cross-linking, and from the viewpoint of the polishing rate, the lower the degree of cross-linking, the more preferable it is, specifically, 50 or less, preferably 30 or less. Further, from the viewpoint of improving the in-plane uniformity of the surface to be polished, the higher the degree of crosslinking, the more preferable it is, specifically, 0.5 or more, preferably 1 or more. Here, the degree of crosslinking is the charged weight% of the copolymerizable crosslinkable monomer per polymer.
[0026]
The thermoplastic resin constituting the polymer particles preferably has a glass transition temperature of 200 ° C. or lower, more preferably 180 ° C. or lower, further preferably 150 ° C. or lower, from the viewpoint of the polishing rate improving effect. Examples of the resin having a glass transition temperature of 200 ° C. or lower include polyethylene (−120 ° C.), polypropylene (−10 ° C.), polystyrene (100 ° C.), polymethyl acrylate (3 ° C.), polymethyl methacrylate (115 ° C .: syndiotactic, 45 ° C .: isotactic), resins such as polybutyl methacrylate (21 ° C.), polyvinyl chloride (87 ° C.), polychloroprene (−50 ° C.), and polyvinyl acetate (28 ° C.). The value of the glass transition temperature is a value described in “Mechanical Properties of Polymer and Composite Material” (1976), pages 316 to 318 of Kagaku Dojin.
[0027]
Polymer particles can be obtained by a method of directly obtaining particles from an ethylenically unsaturated monomer by emulsion polymerization, precipitation polymerization or suspension polymerization, a method of emulsifying and dispersing a polymer, or a method of grinding a bulk resin. Further, the polymer particles thus obtained can be classified and used as necessary. Among them, emulsion polymerization is preferred because polymer particles having a particle diameter useful in the present invention can be easily obtained.
[0028]
The average particle size of the polymer particles is preferably from 10 to 1,000 nm, more preferably from 20 to 800 nm, and still more preferably from 20 to 500 nm, from the viewpoint of improving the polishing rate and flattening characteristics, and from the viewpoint of preventing sedimentation / separation. . The average particle diameter can be measured by a light scattering method or a light diffraction method.
[0029]
The average particle diameter Dp (nm) of the polymer particles preferably satisfies Dp ≦ Di + 50 nm with respect to the average particle diameter Di (nm) of the silica particles from the viewpoint of improving the polishing rate. Here, Dp and Di are values representing the average particle diameter of the polymer particles and the silica particles, respectively, in the unit of nm.
[0030]
Examples of the cationic compound that can be used in the polishing composition used in the present invention include an amine compound, a quaternary ammonium salt compound, a betaine compound, and a compound containing an amino acid compound. Among these cationic compounds, a quaternary ammonium salt compound is preferred from the viewpoint of stability with time.
[0031]
The molecular weight of the cationic compound is preferably from 30 to 10,000 from the viewpoint of water solubility, more preferably from 30 to 1,000, still more preferably from 30 to 500, and most preferably from 40 to 200. The number of amino groups and / or quaternary ammonium groups contained in one molecule of the cationic compound is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 5, from the viewpoint of compoundability. The ratio of the carbon atom to the nitrogen atom (C / N ratio) contained in one molecule of the cationic compound is preferably from 1 to 20, more preferably from 1 to 15, still more preferably from 1 to 10, from the viewpoint of compoundability. .
[0032]
Examples of the amine compound include a monoamine, a polyvalent amine, an amine having an OH group, an amine having an ether group, and a heterocyclic compound having a nitrogen atom.
[0033]
The monoamine is preferably one having 1 to 20 carbon atoms, more preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 4, from the viewpoint of water solubility. Specifically, primary amines such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, valerylamine, isovalerylamine, cyclohexylamine, benzylamine and allylamine , Dimethylamine, methylethylamine, diethylamine, methylpropylamine, methylisopropylamine, ethylpropylamine, methylbutylamine, ethylbutylamine, di-n-propylamine, secondary amines such as diallylamine, trimethylamine, triethylamine, dimethylethylamine, diethylmethyl And tertiary amines such as amine and diisopropylethylamine.
[0034]
As the polyvalent amine, those having 1 to 30 carbon atoms are preferable from the viewpoint of water solubility, 2 to 20 are more preferable, 2 to 15 are more preferable, and 2 to 10 are particularly preferable. Specifically, ethylenediamine, 1,2-propanediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, bis (dimethylamino) methane, N, N-dimethylethylenediamine, N, N′-dimethyl Ethylenediamine, N-ethylethylenediamine, N-methyl-1,3-propanediamine, 1,3-diaminopentane, N-isopropylethylenediamine, N-isopropyl-1,3-propanediamine, N, N, N ′, N ′ -Tetramethylethylenediamine, N, N, N ', N'-tetramethyltrimethylenediamine, N, N, N', N'-tetramethyl-1,2-propanediamine, N, N, 2,2-tetra Methyl-1,3-propanediamine, N, N, N ', N'-tetra Tyltetramethylenediamine, N, N-dimethyl-1,6-diaminohexane, N, N, N ′, N′-tetramethyl-2,2-dimethyl-1,3-propanediamine, N, N, N ′ , N'-tetramethylhexamethylenediamine, diethylenetriamine, bis (3-aminopropyl) amine, N- (3-aminopropyl) -1,3-propanediamine, 3,3'-diamino-N-methyl Dipropylamine, spermidine, N, N, N ', N', N "-pentamethyldiethylenetriamine, 3,3'-iminobis (N, N-dimethylpropylamine), bis (hexamethylene) triamine, triethylenetriamine , N, N'-bis (3-aminopropyl) ethylenediamine, tetraethylenepentamine, etc. Polyvalent amine having 3 or more can be mentioned.
[0035]
Further, as the amine containing an OH group and the amine containing an ether group, those having 1 to 30 carbon atoms are preferable, 2 to 20 are more preferable, 2 to 15 are more preferable, and 10 is particularly preferred. Specifically, monoethanolamine, 1-aminopropanol, 3-aminopropanol, 2-methylaminoethanol, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, N, N-diethyl Hydroxyamine, N, N-dimethylethanolamine, 2-ethylaminoethanol, 1- (dimethylamino) -2-propanol, 3-dimethylamino-1-propanol, 2- (isopropylamino) ethanol, 2- (butylamino) ) Ethanol, 2- (tert-butylamino) ethanol, N, N-diethylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2- (diisopropylamino) ethanol, 2- (dibutylamino) ethanol, 6-dimethylamino-1-hexanol, di Tanolamine, 2-amino-2-methylpropanediol, N-methyldiethanolamine, diisopropanolamine, 2- {2- (dimethylamino) ethoxy} ethanol, N-ethyldiethanolamine, N-butyldiethanolamine, triisopropanolamine, triisopropanolamine OH group-containing amines such as ethanolamine and 2- (2-aminoethylamino) ethanol, 2-methoxyethylamine, 2-amino-1-methoxypropane, 3-methoxypropylamine, 3-ethoxypropylamine, and 3-isopropoxy Ether group-containing amines such as propylamine, bis (2-methoxyethyl) amine, 2,2 ′-(ethylenedioxy) bis (ethylamine), and 4,7,10-trioxa-1,13-tridecanediamine. Can be
[0036]
Other amines include high molecular amines such as polyethyleneimine, polyvinylamine and polyallylamine.
[0037]
Further, a heterocyclic compound containing a nitrogen atom such as piperidine, piperazine, pyridine, pyrazine, pyrrole, triethylenediamine, morpholine, 2-aminopyridine, 3-amino-1,2,4-triazole, and the like are also included.
[0038]
The quaternary ammonium salt compound is preferably a compound having 4 to 20 carbon atoms, more preferably 4 to 15, and further preferably 4 to 7, from the viewpoint of water solubility. However, this carbon number does not include the carbon contained in the counter anion molecule. As the quaternary ammonium salt compound, compounds represented by the following formulas (I) and (II) are preferable.
[0039]
Embedded image

[0040]
[Wherein, R₁, R₂, R₃And R₄Is independently an aliphatic alkyl group having 1 to 8 carbon atoms, a phenyl group, a benzyl group or an alkanol group having 1 to 3 carbon atoms, X⁻Represents a monovalent anion. ]
[0041]
In the formula (I), R₁, R₂, R₃And R₄Is an aliphatic alkyl group having 1 to 8 carbon atoms, a phenyl group, a benzyl group or an alkanol group having 1 to 3 carbon atoms, and from the viewpoint of water solubility, the aliphatic alkyl group is preferably 1 to 6, 4 is more preferred, and 1-2 is still more preferred. Also, X⁻Is a monovalent anion, OH⁻, F⁻, Cl⁻, Br⁻, I⁻, NO₃ ⁻, HSO₄ ⁻, CH₃SO₃ ⁻, H₂PO₄ ⁻, HCOO⁻, CH₃COO⁻, CH₃CH (OH) COO⁻, C₂H₅COO⁻When used for polishing a semiconductor substrate, OH⁻, CH₃COO⁻, HCOO⁻Is preferred. Specific examples of the quaternary ammonium salt compound represented by the formula (I) include tetramethylammonium salts (hydroxide, chloride, bromide, acetate, formate) and tetraethylammonium salts (hydroxide, chloride, bromide, acetate) , Formate), tetrapropylammonium salt (hydroxide, chloride, bromide, acetate, formate), tetrabutylammonium salt (hydroxide, chloride, bromide, acetate, formate), ethyltrimethylammonium salt (hydroxide, chloride, bromide, Acetate, formate), propyltrimethylammonium salt (hydroxide, chloride, bromide, acetate, formate), Rutrimethylammonium salt (hydroxide, chloride, bromide, acetate, formate), N-hydroxyethyl-N, N, N-trimethylammonium salt (hydroxide, chloride, bromide, acetate, formate), N-hydroxypropyl-N N, N, N-trimethylammonium salt (hydroxide, chloride, bromide, acetate, formate), N-hydroxyethyl-N-hydroxypropyl-N, N-dimethylammonium salt (hydroxide, chloride, bromide, acetate, formate) , Phenyltrimethylammonium salt (hydroxide, chloride, bromide, acetate, formate), benzyltrimethylammonium salt (hydroxide Chloride, bromide, acetate, formate), benzyltriethylammonium salts (hydroxide, chloride, bromide, acetate, formate) and the like.
[0042]
Embedded image

[0043]
[Wherein, R₅, R₆, R₇, R₈, R₉And R₁₀Is independently an aliphatic alkyl group having 1 to 8 carbon atoms, a phenyl group, a benzyl group or an alkanol group having 1 to 3 carbon atoms, X⁻Represents a monovalent anion, and n represents an integer of 1 to 12. ]
[0044]
In the formula (II), R₅, R₆, R₇, R₈, R₉And R₁₀Is an aliphatic alkyl group having 1 to 8 carbon atoms, a phenyl group, a benzyl group or an alkanol group having 1 to 3 carbon atoms, and from the viewpoint of water solubility, the aliphatic alkyl group is preferably 1 to 6, 4 is more preferred, and 1-2 is still more preferred. Also, X⁻Is a monovalent anion, OH⁻, F⁻, Cl⁻, Br⁻, I⁻, NO₃ ⁻, HSO₄ ⁻, CH₃SO₃ ⁻, H₂PO₄ ⁻, HCOO⁻, CH₃COO⁻, CH₃CH (OH) COO⁻, C₂H₅COO⁻When used for polishing a semiconductor substrate, OH⁻, CH₃COO⁻And HCOO⁻Is preferable, and n is an integer of 1 to 12, and from the viewpoint of compoundability, 1 to 8 is preferable, and 1 to 6 is more preferable. Specific examples of the quaternary ammonium salt compound represented by the formula (II) include N, N′-tetramethylenebis (trimethylammonium salt) (hydroxide, chloride, bromide, acetate, formate), N, N'-pentamethylenebis (trimethylammonium salt) (hydroxide, chloride, bromide, acetate, formate), N, N'-hexamethylenebis (trimethylammonium salt) (hydroxide, chloride, bromide, acetate, formate), etc. Is mentioned.
[0045]
The betaine compound is preferably a compound having 1 to 20 carbon atoms, more preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 4, from the viewpoint of water solubility.
Specifically, betaine acetate such as trimethylglycine, β-N-alkylaminopropionic acid such as betaine trimethylaminopropionate, and imidazoline carboxylic acid such as 2-methyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine And sulfobetaines such as 2-hydroxy-3-sulfopropyltrimethylbetaine.
[0046]
The amino acid compound is preferably a compound having 1 to 20 carbon atoms, more preferably 1 to 15, more preferably 1 to 10, and particularly preferably 1 to 6 from the viewpoint of water solubility. Specific examples include α-amino acids such as glycine, alanine, serine, tryptophan, glutamine, lysine, and arginine; β-amino acids such as β-alanine; and γ-amino acids such as γ-aminobutyric acid.
[0047]
Among these, propylamine, isopropylamine, butylamine, hexamethylenediamine, N, N, N ', N'-tetramethylhexamethylenediamine, diethylenetriamine are more preferable from the viewpoint of water solubility and flattening characteristics. , Bis (3-aminopropyl) amine, tetramethylammonium salt, N-hydroxypropyl-N, N, N-trimethylammonium salt, N-hydroxyethyl-N-hydroxypropyl-N, N-dimethylammonium salt, N'-hexamethylenebis (trimethylammonium salt), arginine and the like.
[0048]
Examples of the silica particles that can be used in the first polishing composition include colloidal silica particles, fumed silica particles, and surface-modified silica particles. Surface-modified silica particles and the like include those in which metals such as aluminum, titanium, and zirconium and their oxides are adsorbed and / or bonded to the silica particle surfaces directly or via a coupling agent, and silane coupling agents And titanium coupling agent.
[0049]
Colloidal silica particles are prepared by using an alkali metal silicate such as sodium silicate as a raw material, a water glass method of growing silica particles by a condensation reaction in an aqueous solution, or a raw material of tetraethoxysilane or the like, and a water-soluble organic solvent such as alcohol. It can be obtained by an alkoxysilane method in which silica particles are grown by a condensation reaction in contained water. Fumed silica particles can be obtained by a method in which a volatile silicon compound such as silicon tetrachloride is used as a raw material and gas phase hydrolysis is performed at a high temperature of 1000 ° C. or more using an oxyhydrogen burner. These silica particles may be used alone or in combination of two or more.
[0050]
The average particle size of the colloidal silica particles is preferably from 5 to 500 nm, more preferably from 10 to 300 nm, and still more preferably from 20 to 200 nm, from the viewpoint of polishing rate and preventing sedimentation / separation. The average particle size of the colloidal silica particles is an average particle size of primary particles calculated using a specific surface area measured by a BET method. The particle diameter (nm) determined by the BET method is 2720 / specific surface area / specific surface area (m²/ G)｝.
[0051]
The average particle size of the fumed silica particles is preferably from 20 to 2,000 nm, more preferably from 30 to 1,000 nm, and still more preferably from 40 to 800 nm, from the viewpoints of polishing rate and preventing sedimentation / separation. The average particle size of the fumed silica is the average particle size of the secondary particles measured by a light scattering method or a light diffraction method because the fumed silica is secondary aggregated.
[0052]
Examples of the aqueous medium that can be used in the first polishing composition include a mixed medium of water and a solvent that is mixed with water such as alcohol, and it is preferable to use water such as ion-exchanged water.
[0053]
The first polishing composition can be prepared by blending silica particles, polymer particles and a cationic compound in an aqueous medium. Above all, from the viewpoint of dispersion stability of silica particles and polymer particles at the time of compounding, a method of mixing an aqueous dispersion containing silica particles, an aqueous dispersion containing polymer particles, and an aqueous solution in which a cationic compound is dissolved is used. preferable.
[0054]
The aqueous dispersion containing silica particles can be prepared, for example, by the following method. The powdery silica particles are further pulverized as necessary, blended in an aqueous medium, and ultrasonically stirred, kneaded or the like, forcibly dispersed by mechanical force, or grown in an aqueous medium. A method can be used.
[0055]
The aqueous dispersion containing the polymer particles can be prepared, for example, by the following method. A method in which a monomer is polymerized using an aqueous medium or, if necessary, copolymerized with another monomer to obtain polymer particles to be produced and an aqueous medium containing the same as they are.
The monomer is polymerized using an organic solvent or, if necessary, copolymerized with another monomer, and the resulting polymer particles and the organic solvent containing the same are directly solvent-substituted with an aqueous medium by distillation or the like. To obtain an aqueous dispersion. A method of polymerizing using an aqueous medium or an organic solvent, drying and pulverizing the obtained polymer, and then redispersing the obtained powder in an aqueous medium to obtain an aqueous dispersion. Among them, a method of polymerizing a monomer using an aqueous medium, or copolymerizing with another monomer as necessary, and obtaining a polymer particle to be generated and an aqueous medium containing the same as an aqueous dispersion as it is. It is preferable because it is simple and easy to control the average particle size of the obtained polymer particles.
[0056]
The pH of the first polishing composition is preferably from 7 to 13, more preferably from 8 to 12, from the viewpoint of negatively charging the silica particles and the substrate to be polished to promote the formation of the adsorption film by the cationic compound. , 9 to 12 are more preferred.
[0057]
A pH adjuster can be used to adjust the first polishing composition to the above pH. Examples of the pH adjuster include ammonia, potassium hydroxide, sodium hydroxide, water-soluble organic amines, basic substances such as quaternary ammonium hydroxide, acetic acid, oxalic acid, succinic acid, glycolic acid, malic acid, citric acid, and benzoic acid. Acidic substances such as organic acids such as acids and inorganic acids such as nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid.
[0058]
Various additives can be added to the first polishing composition as needed. Examples of the additives include a dispersion stabilizer, a preservative, and the like.
[0059]
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.
[0060]
Examples of the preservative include benzalkonium chloride, benzethonium chloride, 1,2-benzisothiazolin-3-one, hydrogen peroxide, hypochlorite and the like.
[0061]
The kind and content of the silica particles of the second polishing composition used in the present invention may be the same as those of the first polishing composition.
[0062]
The aqueous medium that can be used in the second polishing composition may be the same as the first polishing composition. The lower limit of the aqueous medium content in the second polishing composition is preferably from 50 to 99% by weight, and the upper limit is preferably from 60 to 97% by weight, from the viewpoint of preventing sedimentation and separation, and from the viewpoint of improving the polishing rate. Is more preferred.
[0063]
The second polishing composition can be prepared by blending silica particles with an aqueous medium. The powdery silica particles are further pulverized as necessary, blended in an aqueous medium, and ultrasonically stirred, kneaded or the like, forcibly dispersed by mechanical force, or grown in an aqueous medium. A method can be used.
[0064]
Polymer particles and / or a cationic compound can be added to the second polishing composition as needed. In that case, the content of the polymer particles in the second polishing composition is preferably 1% by weight or less, more preferably 0.1% by weight, from the viewpoint of avoiding an excessive increase in the polishing rate and easily controlling the polishing end timing. It is at most 5% by weight, more preferably less than 0.1% by weight, particularly preferably at most 0.05% by weight. In addition, the content of the cationic compound in the second polishing composition is preferably 0.1% by weight or less, more preferably 0.1% by weight or less, from the viewpoint of securing a polishing rate required for polishing to a target polishing position. It is at most 0.05% by weight, more preferably less than 0.01% by weight, particularly preferably at most 0.005% by weight. The preparation of the second polishing composition may be the same as the preparation of the first polishing composition, especially when the two components are used in combination.
[0065]
The pH of the second polishing composition is the same as that of the first polishing composition in terms of improving the polishing rate based on the etching action of the alkali. A pH adjuster can be used to adjust the pH of the solution. The pH adjuster may be the same as the first polishing composition described above.
[0066]
Various additives can be added to the second polishing composition as needed. These may be the same as those of the first polishing composition.
[0067]
The material of the surface to be polished to which the method for manufacturing a substrate for precision parts of the present invention is applied is, for example, a metal or semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, and the like, and these metals as main components. Alloys, glassy substances such as glass, glassy carbon and amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, titanium nitride and polysilicon, and resins such as polyimide resin. In particular, when polishing a precision component substrate, such as a semiconductor substrate, having a silicon-containing film formed on a surface to be polished such as glass, thermal oxide film, TEOS film, BPSG film, silicon nitride film, or polysilicon film, the efficiency is high. Flattening can be realized.
[0068]
The method for manufacturing a substrate for precision parts of the present invention can be used for a step of polishing and flattening a surface to be polished of a semiconductor substrate which is a kind of substrate for precision parts, for example, a polishing step of a silicon wafer (bare wafer), There are a buried element isolation film forming step, an interlayer insulating film flattening step, a buried metal wiring forming step, a buried capacitor forming step, and the like. The present invention is particularly suitable for a buried element isolation film forming step, an interlayer insulating film flattening step, and a buried capacitor forming step, and is suitably used for manufacturing a memory IC, a logic IC, a system LSI, or the like. Therefore, the present invention relates to a semiconductor device using a precision component substrate obtained by the manufacturing method.
[0069]
There is no particular limitation on the shape of the object to be polished. For example, a shape having a flat portion such as a disk shape, a plate shape, a slab shape, a prism shape, or a shape having a curved surface portion such as a lens may be used as the polishing method of the present invention. It is an object of polishing using 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 precision component substrate on which a thin film is formed and has irregularities on its surface to a desired thickness. Therefore, the present invention relates to a method for flattening a precision component substrate.
[0070]
In the method for producing a precision component substrate having irregularities, the irregularities that are suitable are those having a step amount of 10 to 2000 nm before the first step, and those having a step amount of 100 to 1500 nm. More preferred. Here, the unevenness step can be obtained by a profile measuring device (for example, HLA-100 manufactured by KLA-Tencor).
[0071]
The polishing apparatus used in the method for manufacturing a substrate for precision parts of the present invention is not particularly limited, and a general apparatus can be used. Among them, a polishing apparatus including a jig for holding a substrate to be polished and a polishing cloth is preferably used. As a specific example of the manufacturing method using the polishing apparatus, an organic polymer-based foam, non-foamed and those filled with polymer particles and the like, or a polishing plate attached with a polishing cloth formed of a nonwoven fabric or the like Pressing a jig holding the substrate, or sandwiching the substrate in a polishing plate with a polishing cloth applied thereto, supplying the polishing liquid used in the present invention to the substrate surface, and moving the polishing plate or the substrate while applying a constant pressure Thus, a method of polishing the surface of the substrate can be mentioned.
[0072]
The first step and the second step may be continuously performed on the same polishing cloth, or after the first step, a rinsing step, a dressing step, a buff polishing step, a cleaning step, or the like is performed, and then a second step. May be implemented. Further, after the first step is performed, if necessary, a rinsing step, a buff polishing step, a cleaning step, or the like is performed, and then the substrate may be moved to a different polishing cloth to perform the second step.
[0073]
The method for supplying the polishing liquid is preferably a method in which the components of the polishing liquid are supplied to the polishing cloth in a state of being sufficiently mixed. Specifically, the components of the polishing liquid may be premixed and adjusted to a predetermined concentration and supplied to the polishing cloth by a pump or the like, or the aqueous dispersion or aqueous solution of the components may be individually Alternatively, a method may be used in which a premix liquid in which a part thereof is mixed is prepared, and each is supplied by a pump or the like and mixed in a supply pipe, thereby supplying a polishing liquid of a predetermined concentration onto the polishing cloth. When mixing in the supply pipe, it is preferable to provide a mixing device that promotes stirring in the supply pipe so that mixing can be sufficiently performed.
[0074]
【Example】
"Weight%" in the following examples is based on the total amount of the aqueous dispersion of the polymer particles or the total amount of the polishing composition. “Parts” indicates parts by weight.
[0075]
Synthesis Example (Synthesis of polymer particles)
27 parts of styrene, 3 parts of 55% divinylbenzene, 1.5 parts of fatty acid potassium (KS soap, manufactured by Kao Corporation) and 68.5 parts of ion-exchanged water were charged into a 2 L separable flask, and the inside of the flask was filled with nitrogen gas. This was replaced and the temperature was raised to 65 ° C. 0.06 parts of potassium persulfate was charged into the flask and polymerized for 3 hours to obtain an aqueous dispersion of polymer particles. The average particle diameter measured by a light scattering method (trade name: Laser Zeta Electrometer ELS8000, manufactured by Otsuka Electronics Co., Ltd.) was 71 nm.
[0076]
Examples and comparative examples
<Preparation of polishing liquid>
To 2.3 parts of N-hydroxypropyl-N, N, N-trimethylammonium formate (manufactured by Kao Corporation, trade name: Kaorizer No. 430), 51 parts of ion-exchanged water is added and dissolved by stirring. Under stirring, 6.7 parts of an aqueous dispersion of polymer particles obtained in Synthesis Example 1 (2 parts of polymer particles) and an aqueous dispersion of colloidal silica (manufactured by DuPont, trade name: Syton OX-K50, effective) 40 parts by mass (average particle diameter: 40 nm) and, if necessary, adjusting the pH of the polishing composition with an aqueous solution of potassium hydroxide so as to be 10.5 to 11.5. A polishing liquid A to be used was obtained.
[0077]
Next, 40 parts of an aqueous dispersion of colloidal silica (manufactured by DuPont, trade name: Syton OX-K50, effective component 50%, average particle diameter 40 nm) is added to 60 parts of ion-exchanged water, and the mixture is stirred. The polishing liquid B used in the examples was obtained by adjusting the pH of the polishing liquid composition with an aqueous potassium hydroxide solution so as to be 10.5 to 11.5.
[0078]
Finally, 52 parts of a commercially available fumed silica polishing liquid (trade name: SEMI-SPERSE25, manufactured by Cabot Microelectronics Corporation) was added to 48 parts of ion-exchanged water, followed by stirring to obtain a polishing liquid used in Comparative Examples.
Using the polishing liquid thus prepared, a polishing experiment was performed under the following conditions and evaluated.
[0079]
<Polishing conditions>
Polishing tester: Lappmaster SFT LP-541 (platen diameter 540mm)
Polishing pad: IC-1000 / Sub400 manufactured by Rodale Nitta
Platen rotation speed: 60 rpm
Carrier rotation speed: 61 rpm
Polishing liquid supply amount: 200 (g / min)
Polishing load: 196-490 (hPa)
[0080]
<Polishing rate measurement / evaluation method>
1. Blanket wafer
A 2 μm PE-TEOS film (blanket wafer) formed on an 8-inch (200 mm) silicon substrate as a material to be polished is polished for 2 minutes under the above-mentioned conditions, and the polishing rate is determined from the difference in the remaining film thickness before and after polishing. (Nm / min) was determined. The residual film thickness was measured using a light interference type film thickness meter (trade name: VM-1000, manufactured by Dainippon Screen Mfg. Co., Ltd.). The relationship between the polishing load and the polishing rate was plotted to evaluate the polishing characteristics.
[0081]
2. Pattern wafer
In order to evaluate the flattening characteristics, a commercially available wafer for CMP characteristics evaluation (pattern wafer, trade name: SKW7-2, manufactured by SKW Associates, Inc .: 800 nm unevenness step) was used as the material to be polished. The process of flattening the unevenness of the previously formed wafer by polishing was measured and evaluated. Specifically, first, prior to the start of polishing, GRADUAL D10, D50, D90 patterns (D10: Line & Space pattern with a convex width of 10 μm / concave width of 90 μm, D50: Line & Space pattern with a convex width of 50 μm / concave width of 50 μm, D90 on the wafer) : The initial surface step 5 (measuring method described above), the initial convex part film thickness 3 and the initial concave part film thickness 4 (measuring method described above) of the Line & Space pattern (protrusion width 90 μm / recess width 10 μm) shown in FIG. 2 were measured. Then, the substrate step 2 is calculated (substrate step 2 = initial surface step 5 + initial concave film thickness 4−initial convex film thickness 3). Subsequently, the GRADUAL D10, D50, D90 patterns (D10: Line & Space pattern with a convex width of 10 μm / concave width of 90 μm, D50: Line & Space pattern with a convex width of 50 μm / concave width of 50 μm, D90 on the wafer every minute under the above setting conditions. : Measure the remaining film thickness of the convex and concave portions (Line & Space pattern having a convex portion width of 90 μm / concave portion width of 10 μm) (the measuring method is described above), and from these, the height of the convex portions and concave portions from the reference plane 1 shown in FIG. Are plotted with respect to the polishing time, and the flattening characteristics and pattern dependence are evaluated.
[0082]
<Blanket wafer polishing results>
FIGS. 3 and 4 show the relationship between the polishing load and the polishing rate in the polishing of the blanket wafer performed using the polishing liquids A and B of the examples. First, as shown in FIG. 3, the polishing rate of the polishing liquid A was suppressed at a low load (196 hPa) as compared with the comparative example, while the polishing rate was improved at a high load (490 hPa). You can see that it is done. Next, it can be seen from FIG. 4 that the polishing liquid B has polishing characteristics similar to those of the comparative example, and does not show a bending point of the polishing rate.
[0083]
<Pattern wafer polishing results>
In the example, polishing was performed for 3 minutes in the first step using the polishing liquid A, and then for 1 minute in the second step using the polishing liquid B, for a total of 4 minutes. On the other hand, in the comparative example, polishing was performed for 4 minutes. In both cases, the polishing load was 294 hPa.
[0084]
FIGS. 5 to 8 show a process in which the height and the level difference between the projections and the recesses with respect to the reference surface change as the polishing progresses, and the process reaches flattening. In both the examples and comparative examples, the process proceeds almost equally until 1 minute after polishing (FIG. 5), but after 2 minutes after polishing (FIG. 6), the height between the patterns in the comparative example, particularly between D10 and D90, is increased. It can be seen that the variation of the pattern becomes conspicuous, and a new step between the patterns is newly generated. On the other hand, in the embodiment, variation in height between patterns is relatively small.
[0085]
Further, after 3 minutes of polishing (FIG. 7), in the comparative example, in addition to the variation in height between the patterns, excessive polishing is conspicuous because polishing continues to proceed, and particularly the height of D10 is remarkably reduced. . On the other hand, in the example, excessive polishing is suppressed because the polishing does not progress as the step decreases, and the state in which the variation in height between patterns is small is maintained. In this embodiment, the polishing liquid is changed to the polishing liquid B, and the process proceeds to the second step.
[0086]
Finally, one minute after the second step of the example (FIG. 8) (four minutes after in the comparative example), although the comparative example has completed the planarization in each pattern, the height between the patterns is significantly different. It can be seen that advanced flattening is incomplete, leaving a new step between the patterns.
[0087]
On the other hand, in the example, the same level of polishing as in the comparative example was performed for a total of 4 minutes, and the surface was flattened regardless of the pattern or between the patterns, indicating that a high degree of flattening was realized. In addition, in the examples, since excessive polishing is not performed and a layer to be polished having a sufficient thickness is stored, it can be seen that by processing in a later step, it is possible to polish a pattern having various thicknesses. .
[0088]
【The invention's effect】
By using the method of manufacturing a substrate for precision parts of the present invention, a thin film is formed on a surface by a CMP technique for performing buried element isolation, flattening an interlayer insulating film, forming a buried metal wiring, forming a plug, or forming a buried capacitor. Since even a substrate having irregularities can be highly flattened, a highly planarized precision component substrate, especially a precision component substrate having a surface on which a thin film is formed and having a desired thickness. The effect that it can manufacture efficiently is produced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a change in polishing rate with respect to a polishing load when an object to be polished having no concavo-convex pattern is polished using the polishing liquid composition of the present invention and a normal silica-based polishing liquid. It is.
FIG. 2 is a schematic diagram showing each part of the pattern wafer measured when evaluating the polishing result of the pattern wafer performed in the embodiment.
FIG. 3 is a schematic diagram showing a change in polishing rate with respect to a polishing load when a blanket wafer is polished using the polishing liquid A obtained in the example and the polishing liquid obtained in the comparative example.
FIG. 4 is a schematic diagram showing a change in a polishing rate with respect to a polishing load when a blanket wafer is polished using the polishing liquid B obtained in the example and the polishing liquid obtained in the comparative example.
FIG. 5 is a graph showing changes in height and height of a convex portion and a concave portion with respect to a reference surface after one minute of polishing performed in Examples and Comparative Examples. In the example, one minute after the first polishing step is shown.
FIG. 6 is a graph showing changes in height and height of a convex portion and a concave portion with respect to a reference surface after two minutes of polishing performed in Examples and Comparative Examples. In the examples, two minutes after the first polishing step are shown.
FIG. 7 is a graph showing changes in height and height of a convex portion and a concave portion with respect to a reference surface after three minutes of polishing performed in Examples and Comparative Examples. In the example, three minutes after the first polishing step is shown.
FIG. 8 is a graph showing changes in height and height difference between a convex portion and a concave portion with respect to a reference plane after 4 minutes of polishing performed in Examples and Comparative Examples. In the examples, one minute after the second polishing step is shown.
[Explanation of symbols]
1 Reference plane
2 substrate step
3 Initial convex part film thickness
4 Initial recess thickness
5 Initial surface step
6 Silicon substrate
7 TEOS film
8 Remaining film thickness of protrusion
9 Remaining recess thickness

Claims (7)

A method for manufacturing a precision component substrate, comprising the following first step and second step.
First step: a step of performing polishing with a polishing load of 50 to 1000 hPa (P1) using a first polishing composition containing silica particles, polymer particles and a cationic compound in an aqueous medium. Polishing with a polishing load of 50 to 1000 hPa (P2) using a second polishing composition containing silica particles in an aqueous medium. In the first polishing composition, the content of the silica particles is 1 to 50% by weight, the content of the polymer particles is 0.1 to 20% by weight, and the content of the cationic compound is 0.01 to 20% by weight. %. The method for producing a precision component substrate according to claim 1. 3. The method for producing a precision component substrate according to claim 1, wherein the polymer particles are a thermoplastic resin having a glass transition temperature of 200 ° C. or less. The method for producing a precision component substrate according to any one of claims 1 to 3, wherein the cationic compound is at least one selected from the group consisting of an amine compound, a quaternary ammonium salt, a betaine compound, and an amino acid. The method for producing a precision component substrate according to any one of claims 1 to 4, wherein the substrate is a substrate on which a film containing at least silicon is formed on a surface to be polished. A semiconductor device using a precision component substrate obtained by the manufacturing method according to claim 1. A method for planarizing a precision component substrate, comprising the following first step and second step.
First step: a step of performing polishing at a polishing load of 50 to 1000 hPa (P1) using a first polishing composition containing silica particles, polymer particles and a cationic compound in an aqueous medium,
Second step: a step of performing polishing with a polishing load of 50 to 1000 hPa (P2) using a second polishing composition containing silica particles in an aqueous medium.

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