JP6724127B2 - Polishing composition, method for producing the same, and polishing method - Google Patents
Polishing composition, method for producing the same, and polishing method Download PDFInfo
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本発明は、研磨組成物及び研磨組成物の製造方法に関する。また、本発明は、研磨組成物を用いた研磨方法にも関する。 The present invention relates to a polishing composition and a method for producing a polishing composition. The present invention also relates to a polishing method using the polishing composition.
半導体集積回路の製造技術の向上に伴い半導体素子の高集積化、高速動作が求められるようになり、半導体素子における微細回路の製造工程において要求される半導体基板表面の平坦性はより厳しくなってきている。そのため、化学機械研磨（Ｃｈｅｍｉｃａｌ Ｍｅｃｈａｎｉｃａｌ Ｐｏｌｉｓｈｉｎｇ：ＣＭＰ）は半導体素子の製造工程に不可欠な技術となっている。 With the improvement in the manufacturing technology of semiconductor integrated circuits, higher integration of semiconductor elements and higher speed operation are required, and the flatness of the semiconductor substrate surface required in the manufacturing process of fine circuits in semiconductor elements becomes more severe. There is. Therefore, chemical mechanical polishing (CMP) has become an indispensable technique in the manufacturing process of semiconductor devices.
ＣＭＰの原理としては、例えば、単結晶シリコン基板等の半導体基板を保持しながら、定盤上に貼り付けた研磨パッド上に押し付けつつ、砥粒や試薬を含む研磨組成物を研磨パッド上に供給しながら半導体基板と研磨パッドを相対的に運動させる。このようにして、試薬による化学的な反応と、砥粒による機械的な研磨効果により基板表面の凹凸を削り、表面を平坦化することができる。 As the principle of CMP, for example, while holding a semiconductor substrate such as a single crystal silicon substrate and pressing it onto a polishing pad attached on a surface plate, a polishing composition containing abrasive grains and a reagent is supplied onto the polishing pad. While moving the semiconductor substrate and the polishing pad relatively. In this manner, the chemical reaction of the reagent and the mechanical polishing effect of the abrasive grains can remove the irregularities on the substrate surface and flatten the surface.
また、コスト低減のため半導体素子の生産性の向上が求められ、半導体基板の可能な限り広い領域で素子を作製できるよう、基板端面付近の平坦性が重要視されるようになっており、半導体基板の広い領域において高い平坦性を実現させることが課題となっている。 Further, in order to reduce the cost, it is required to improve the productivity of semiconductor devices, and the flatness in the vicinity of the end face of the substrate is becoming important so that the device can be manufactured in the widest possible area of the semiconductor substrate. Achieving high flatness over a wide area of the substrate is an issue.
しかしながら、一般的に半導体基板の端面から数ミリメートル程度の領域では面ダレによる外周部が基板中心付近に比べ薄くなり平坦性が悪化する傾向がある。そのため半導体基板外周部における平坦性の悪化が歩留りの低下の原因となっている。 However, in general, in a region of several millimeters from the end surface of the semiconductor substrate, the outer peripheral portion due to surface sagging becomes thinner than that near the center of the substrate, and flatness tends to deteriorate. Therefore, the deterioration of flatness in the outer peripheral portion of the semiconductor substrate causes a decrease in yield.
半導体素子の作製工程、特にリソグラフィー工程における半導体基板平坦性の尺度としてＳＦＱＲ（Ｓｉｔｅ ｆｒｏｎｔ ｓｕｒｆａｃｅ ｒｅｆｅｒｅｎｃｅｄ ｌｅａｓｔ ｓｑｕａｒｅｓ ｒａｎｇｅ）がよく用いられる。ＳＦＱＲは任意の寸法のサイトを指定し、このサイト領域において最小２乗法により定めた基準面からの偏差の範囲で定義される。上記面ダレの影響により半導体基板外周部のＳＦＱＲが悪化する傾向がある。 SFQR (Site front surface referred least squares range) is often used as a measure of the flatness of a semiconductor substrate in a semiconductor device manufacturing process, particularly in a lithography process. SFQR designates a site of an arbitrary size, and is defined in the range of deviation from the reference plane defined by the least square method in this site region. The SFQR in the outer peripheral portion of the semiconductor substrate tends to deteriorate due to the influence of the surface sag.
また、上記のような平坦化のためのＣＭＰにおいて、半導体基板に金属不純物が付着してしまうという問題が有る。これは、砥粒に含まれる金属不純物が研磨加工中に半導体基板に拡散してしまうことが原因と考えられる。 Further, in the CMP for planarization as described above, there is a problem that metal impurities are attached to the semiconductor substrate. It is considered that this is because the metal impurities contained in the abrasive grains diffuse into the semiconductor substrate during the polishing process.
また、研磨工程に要する時間が長い、すなわち所定の研磨代まで研磨するまでにかかる時間が長くなるほど半導体基板の生産性が悪化する。従って、半導体基板を効率良く研磨するために、高い研磨速度を得ることが可能な研磨組成物が要求されている。 In addition, as the time required for the polishing step is longer, that is, the longer it takes to polish to a predetermined polishing allowance, the productivity of the semiconductor substrate is deteriorated. Therefore, in order to efficiently polish a semiconductor substrate, a polishing composition capable of obtaining a high polishing rate is required.
本発明は前述のような問題に鑑みてなされたもので、内周部だけでなく外周部の平坦性も高く、金属不純物による汚染が少ない半導体基板を、生産性良く得ることが可能な研磨組成物を提供することを目的とする。また、本発明は、このような研磨組成物を製造することが可能な研磨組成物の製造方法を提供することも目的とする。 The present invention has been made in view of the above-mentioned problems, and a polishing composition capable of obtaining a semiconductor substrate having high flatness not only in the inner peripheral portion but also in the outer peripheral portion and less contaminated by metal impurities with good productivity. The purpose is to provide things. Moreover, this invention also makes it the objective to provide the manufacturing method of the polishing composition which can manufacture such a polishing composition.
上記目的を達成するために、本発明は、砥粒として酸化ジルコニウムを含む研磨組成物であって、ｐＨが１１．０以上１２．５未満のものであり、前記酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものであることを特徴とする研磨組成物を提供する。 In order to achieve the above object, the present invention is a polishing composition containing zirconium oxide as abrasive grains, having a pH of 11.0 or more and less than 12.5, and magnesium contained in the zirconium oxide, Provided is a polishing composition characterized in that the concentration of each element of aluminum and iron is less than 1 ppm.
このような研磨組成物であれば、半導体基板の金属不純物汚染を抑制することができ、かつ、酸化ジルコニウムの機械的研磨作用と研磨組成物の化学的研磨作用の効果を調和させることで面ダレの影響を抑え、半導体基板の広い領域において高い平坦性を有する半導体ウェーハを生産性良く得ることができる。酸化ジルコニウムを砥粒として用いることで、ウェーハの平坦性を向上できる。酸化ジルコニウムにおいて、ジルコニウム元素以外の上記の金属元素の濃度が１ｐｐｍ未満であれば、研磨後の半導体基板から検出される金属不純物の濃度を、特に、それぞれ１．０×１０１０ａｔｏｍ／ｃｍ２未満に低減することができる。また、研磨組成物のｐＨが１１．０以上であることで、十分な化学的研磨作用が得られ、半導体基板の平坦性を向上できるとともに、高い研磨速度も得られる。研磨組成物のｐＨが１２．５未満であることで、化学的研磨作用が強くなり過ぎることが無く、面ダレの発生を抑制することができる。 With such a polishing composition, it is possible to suppress the contamination of the semiconductor substrate with metal impurities, and by adjusting the mechanical polishing action of zirconium oxide and the chemical polishing action of the polishing composition, it is possible to reduce the surface sag. It is possible to obtain the semiconductor wafer having a high flatness in a wide area of the semiconductor substrate with high productivity by suppressing the influence of the above. By using zirconium oxide as the abrasive grains, the flatness of the wafer can be improved. In zirconium oxide, if the concentration of the above metal elements other than zirconium is less than 1 ppm, the concentration of the metal impurities detected from the semiconductor substrate after polishing is particularly less than 1.0×10 10 atom/cm 2. Can be reduced to When the pH of the polishing composition is 11.0 or higher, a sufficient chemical polishing action can be obtained, the flatness of the semiconductor substrate can be improved, and a high polishing rate can be obtained. When the pH of the polishing composition is less than 12.5, the chemical polishing action does not become too strong, and the occurrence of surface sagging can be suppressed.
このとき、前記酸化ジルコニウムの含有量が前記研磨組成物全体の０．１〜１０質量％であることが好ましい。 At this time, the content of the zirconium oxide is preferably 0.1 to 10% by mass of the entire polishing composition.
砥粒である酸化ジルコニウムの含有量が０．１質量％以上であれば、十分な研磨速度を得ることができる。酸化ジルコニウムの含有量が１０質量％以下であれば、半導体基板の表面にスクラッチなどの欠陥が発生し難い。 When the content of zirconium oxide as the abrasive grains is 0.1% by mass or more, a sufficient polishing rate can be obtained. When the content of zirconium oxide is 10 mass% or less, defects such as scratches are unlikely to occur on the surface of the semiconductor substrate.
またこのとき、本発明の研磨組成物は、さらに、水溶性高分子としてノニオン性界面活性剤、又はアニオン性界面活性剤、あるいはこれらの両方を含むことが好ましい。 At this time, the polishing composition of the present invention preferably further contains a nonionic surfactant, an anionic surfactant, or both as a water-soluble polymer.
研磨組成物中に含まれている水溶性高分子は、半導体基板表面の被研磨表面との相互作用、及び砥粒であるジルコニウム酸化物の表面との相互作用により半導体基板の研磨面をスクラッチなどの欠陥から保護する効果及び酸化ジルコニウムの凝集を防止する効果がある。 The water-soluble polymer contained in the polishing composition scratches the polishing surface of the semiconductor substrate due to the interaction with the surface to be polished of the surface of the semiconductor substrate and the surface of the zirconium oxide which is an abrasive grain. It has an effect of protecting from defects of zirconium and an effect of preventing agglomeration of zirconium oxide.
このとき、本発明の研磨組成物は、前記ノニオン性界面活性剤として、ポリビニルピロリドン、ポリビニルアルコール、ポリアクリルアミド、ポリエチレングリコール、ポリオキシエチレンアルキルエーテル、及びポリエーテルのうち１種類以上を含有することが好ましい。 At this time, the polishing composition of the present invention may contain, as the nonionic surfactant, one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, polyethylene glycol, polyoxyethylene alkyl ether, and polyether. preferable.
本発明では、上記のようなノニオン性界面活性剤を好適に用いることができる。 In the present invention, the above nonionic surfactants can be preferably used.
またこのとき、本発明の研磨組成物は、前記アニオン性界面活性剤として、ポリアクリル酸あるいはその塩、ポリスルホン酸あるいはその塩、及びポリカルボン酸あるいはその塩のうち１種類以上を含有することが好ましい。 At this time, the polishing composition of the present invention may contain, as the anionic surfactant, one or more of polyacrylic acid or a salt thereof, polysulfonic acid or a salt thereof, and polycarboxylic acid or a salt thereof. preferable.
本発明では、上記のようなアニオン性界面活性剤を好適に用いることができる。 In the present invention, the above-mentioned anionic surfactant can be preferably used.
このとき、前記水溶性高分子の含有量が研磨組成物全体の０．００１〜０．５質量％であることが好ましい。 At this time, the content of the water-soluble polymer is preferably 0.001 to 0.5 mass% of the entire polishing composition.
研磨組成物全体に対する水溶性高分子の濃度が０．００１質量％以上であれば、上述した研磨砥粒の凝集抑制効果及び被研磨面の保護効果を十分に得ることができる。研磨組成物全体に対する水溶性高分子の濃度が０．５質量％以下であれば、研磨速度の低下及び研磨組成物の発泡を防止することができる。 When the concentration of the water-soluble polymer with respect to the entire polishing composition is 0.001% by mass or more, the effect of suppressing the agglomeration of the polishing abrasive grains and the effect of protecting the surface to be polished can be sufficiently obtained. When the concentration of the water-soluble polymer with respect to the entire polishing composition is 0.5% by mass or less, it is possible to prevent the polishing rate from decreasing and foaming of the polishing composition.
またこのとき、本発明の研磨組成物が、さらに、酸化剤を含むことが好ましい。 At this time, it is preferable that the polishing composition of the present invention further contains an oxidizing agent.
研磨組成物が酸化剤を含むことにより、半導体基板の表面を酸化でき、研磨をより効果的に促進できる。 When the polishing composition contains an oxidizing agent, the surface of the semiconductor substrate can be oxidized and polishing can be more effectively promoted.
このとき、前記酸化剤の含有量が研磨組成物全体の０．０１〜１．０質量％であることが好ましい。 At this time, the content of the oxidizing agent is preferably 0.01 to 1.0 mass% of the entire polishing composition.
酸化剤の含有量が研磨組成物に対して０．０１質量％以上であれば、酸化剤による研磨の促進効果を十分に得られる。酸化剤の含有量が研磨組成物に対して１．０質量％以下であれば、化学的研磨作用が強くなり過ぎることが無く、面ダレの発生をより抑制することができる。 When the content of the oxidizing agent is 0.01% by mass or more based on the polishing composition, the effect of promoting polishing by the oxidizing agent can be sufficiently obtained. When the content of the oxidizing agent is 1.0% by mass or less based on the polishing composition, the chemical polishing action does not become too strong, and the occurrence of surface sagging can be further suppressed.
またこのとき、本発明の研磨組成物は、前記酸化剤として過酸化水素を含むことが好ましい。 At this time, the polishing composition of the present invention preferably contains hydrogen peroxide as the oxidizing agent.
本発明において、酸化剤として過酸化水素を使用することが好適である。 In the present invention, it is preferable to use hydrogen peroxide as the oxidizing agent.
また、上記目的を達成するために、本発明は、上記のいずれかの研磨組成物を用いて半導体基板を研磨することを特徴とする研磨方法を提供する。 Further, in order to achieve the above object, the present invention provides a polishing method characterized by polishing a semiconductor substrate using any one of the above polishing compositions.
本発明の研磨組成を用いて半導体基板を研磨すれば、内周部だけでなく外周部の平坦性も高く、金属不純物による汚染が少ない半導体基板を研磨によって生産性良く得ることができる。 By polishing a semiconductor substrate using the polishing composition of the present invention, a semiconductor substrate having high flatness not only in the inner peripheral portion but also in the outer peripheral portion and less contaminated by metal impurities can be obtained with high productivity.
このとき、半導体基板を単結晶シリコン基板とすることができる。 At this time, the semiconductor substrate can be a single crystal silicon substrate.
本発明の研磨方法は、特に、単結晶シリコン基板の研磨に好適に使用される。 The polishing method of the present invention is particularly preferably used for polishing a single crystal silicon substrate.
また、上記目的を達成するために、本発明は、砥粒として酸化ジルコニウムを含む研磨組成物の製造方法であって、前記酸化ジルコニウムとして、前記酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものを準備する工程と、前記準備した酸化ジルコニウムを水に添加する工程と、前記酸化ジルコニウムを添加した溶液にｐＨ調整剤を添加することで、前記溶液のｐＨを１１．０以上１２．５未満に調整する工程とを含み、前記ｐＨを調製した後の溶液を用いて研磨組成物を製造することを特徴とする研磨組成物の製造方法を提供する。 In order to achieve the above object, the present invention is a method for producing a polishing composition containing zirconium oxide as abrasive grains, wherein the zirconium oxide contains magnesium, aluminum and iron elements contained in the zirconium oxide. To prepare a solution having a concentration of less than 1 ppm, adding the prepared zirconium oxide to water, and adding a pH adjuster to the solution containing zirconium oxide to adjust the pH of the solution to 11 A step of adjusting the pH to 0 or more and less than 12.5, and producing a polishing composition using the solution after adjusting the pH, and a method for producing the polishing composition.
このような製造方法によって、研磨速度を向上させ、半導体基板の内周部だけでなく外周部の平坦性も高くでき、金属不純物による汚染を少なくできる研磨組成物を製造することができる。 By such a manufacturing method, it is possible to manufacture a polishing composition in which the polishing rate can be improved, the flatness of not only the inner peripheral portion of the semiconductor substrate but also the outer peripheral portion thereof can be enhanced, and contamination by metal impurities can be reduced.
本発明によって、内周部だけでなく外周部の平坦性も高く、金属不純物による汚染が少ない半導体基板を生産性良く得ることができる。 According to the present invention, a semiconductor substrate having high flatness not only in the inner peripheral portion but also in the outer peripheral portion and less contaminated by metal impurities can be obtained with high productivity.
以下、本発明について実施の形態を説明するが、本発明はこれに限定されるものではない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
本発明の研磨組成物は、砥粒として酸化ジルコニウムを含むスラリーであり、酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものである。また、本発明の研磨組成物は、ｐＨが１１．０以上１２．５未満である。 The polishing composition of the present invention is a slurry containing zirconium oxide as abrasive grains, and the concentration of each element of magnesium, aluminum and iron contained in zirconium oxide is less than 1 ppm. The polishing composition of the present invention has a pH of 11.0 or more and less than 12.5.
砥粒として酸化ジルコニウムを使用することで、コロイダルシリカなどを砥粒として用いた場合よりも、高い研磨速度及び平坦性が得られる。また、酸化ジルコニウムにおいて、ジルコニウム元素以外の上記の金属元素の濃度が１ｐｐｍ未満であれば、研磨加工中に半導体基板へ金属不純物が拡散し難く、特に、研磨後の半導体基板から検出される金属不純物の濃度を、それぞれ１．０×１０１０ａｔｏｍ／ｃｍ２未満に低減することができる。また、研磨組成物のｐＨが１１．０以上であることで、十分な化学的研磨作用が得られ、半導体基板の平坦性を向上できるとともに、高い研磨速度も得られる。一方、ｐＨが１１．０未満であると研磨組成物の化学的研磨作用が不足し、半導体基板の平坦性を損なう。さらに、研磨速度が低下し生産性も悪化する。また、研磨組成物のｐＨが１２．５未満であることで、化学的研磨作用が強くなり過ぎることが無く、面ダレの発生を抑制することができる。一方、ｐＨが１２．５以上となると研磨組成物の化学的研磨作用が強くなりすぎて面ダレを促進することになり半導体基板の平坦性が低下する。 By using zirconium oxide as the abrasive grains, higher polishing rate and flatness can be obtained than when colloidal silica or the like is used as the abrasive grains. Further, in zirconium oxide, if the concentration of the above metal elements other than zirconium element is less than 1 ppm, it is difficult for the metal impurities to diffuse into the semiconductor substrate during the polishing process. Can be reduced to less than 1.0×10 10 atoms/cm 2 respectively. When the pH of the polishing composition is 11.0 or higher, a sufficient chemical polishing action can be obtained, the flatness of the semiconductor substrate can be improved, and a high polishing rate can be obtained. On the other hand, when the pH is less than 11.0, the chemical polishing action of the polishing composition is insufficient, and the flatness of the semiconductor substrate is impaired. Further, the polishing rate is lowered and the productivity is deteriorated. Further, when the pH of the polishing composition is less than 12.5, the chemical polishing action does not become too strong, and the occurrence of surface sagging can be suppressed. On the other hand, when the pH is 12.5 or more, the chemical polishing action of the polishing composition becomes too strong, which promotes surface sagging, and the flatness of the semiconductor substrate deteriorates.
また、本発明の研磨組成物中において、酸化ジルコニウムの平均１次粒子径が５ｎｍ以上１００ｎｍ未満であることが好ましい。酸化ジルコニウムの１次粒子径が５ｎｍ以上であれば、十分な研磨速度を得ることができる。酸化ジルコニウムの１次粒子径が１００ｎｍ未満であれば、粒子が大きすぎないためスクラッチが発生し難い。 Further, in the polishing composition of the present invention, the average primary particle diameter of zirconium oxide is preferably 5 nm or more and less than 100 nm. When the primary particle diameter of zirconium oxide is 5 nm or more, a sufficient polishing rate can be obtained. When the primary particle diameter of zirconium oxide is less than 100 nm, scratches are less likely to occur because the particles are not too large.
酸化ジルコニウムの１次粒子径は、透過型電子顕微鏡（ＴＥＭ）あるいは走査型電子顕微鏡（ＳＥＭ）により得られる粒子画像を計測し、粒子１００個以上の定方向最大径、即ちフェレ（Ｆｅｒｅｔ）径の平均値から計算される。酸化ジルコニウム粒子の粒度分布はこの粒径範囲内であることが好ましいが、特に制限されることはなく、目的に合わせ適宜変化させてよい。 The primary particle diameter of zirconium oxide is measured by measuring a particle image obtained by a transmission electron microscope (TEM) or a scanning electron microscope (SEM), and the maximum unidirectional diameter of 100 particles or more, that is, the Feret diameter is obtained. Calculated from the average value. The particle size distribution of zirconium oxide particles is preferably within this particle size range, but is not particularly limited and may be appropriately changed depending on the purpose.
また、酸化ジルコニウムの１次粒子の形状は特に限定されないが研磨傷の発生を抑制するために球形であることが好ましい。 The shape of the primary particles of zirconium oxide is not particularly limited, but is preferably spherical in order to suppress the occurrence of polishing scratches.
酸化ジルコニウムの結晶構造については特に制限されず、アモルファス、単斜晶系、正方晶、立方晶系であっても良い。また、単一の結晶相であっても良いし、複数の結晶相を有していても良く、結晶構造は目的に応じ適宜選択できる。 The crystal structure of zirconium oxide is not particularly limited, and may be amorphous, monoclinic, tetragonal, or cubic. Further, it may have a single crystal phase or a plurality of crystal phases, and the crystal structure can be appropriately selected according to the purpose.
酸化物ジルコニウムの含有量は研磨組成物全体に対して、０．１質量％以上１０質量％以下が好ましく、０．４質量％以上５質量％以下であることが特に望ましい。酸化物ジルコニウムの含有量が０．１質量％以上であれば、充分な研磨速度を得ることができる。また、酸化物ジルコニウムの含有量が１０質量％以下であれば、半導体基板にスクラッチ等の欠陥が発生し難い。 The content of zirconium oxide is preferably 0.1% by mass or more and 10% by mass or less, and particularly preferably 0.4% by mass or more and 5% by mass or less, based on the entire polishing composition. When the content of zirconium oxide is 0.1% by mass or more, a sufficient polishing rate can be obtained. If the content of zirconium oxide is 10 mass% or less, defects such as scratches are less likely to occur on the semiconductor substrate.
また、上述のように、本発明において、酸化ジルコニウム中に含まれるジルコニウム以外の上記のそれぞれの金属不純物の濃度は１ｐｐｍ未満である。このような、金属不純物の少ないナノサイズの酸化ジルコニウムは、特に限定されることはないが、例えば、溶媒抽出法などによって精製した原料（例えば、特許文献１、及び非特許文献１を参照）を用いた水熱合成法（例えば、特許文献２を参照）、加水分解法や沈殿法（例えば、特許文献３を参照）等により製造することができる。
Further, as described above, in the present invention, the concentration of each of the above metal impurities other than zirconium contained in zirconium oxide is less than 1 ppm. Such nano-sized zirconium oxide containing few metal impurities is not particularly limited, but for example, a raw material purified by a solvent extraction method (see, for example,
また、上述のように本発明の研磨組成物のｐＨは１１．０以上１２．５未満である。研磨組成物のｐＨを１１．０以上１２．５未満とするために、本発明の研磨組成物にｐＨ調整剤を加えることができる。ｐＨ調整剤の種類は特に限定されず、水酸化カリウム水溶液や水酸化テトラメチルアンモニウム溶液、アンモニア水などが例示される。なお、ｐＨ調整剤としては、カリウム等のアルカリ金属やカルシウム等のアルカリ土類金属を含んでよい。これは、これらの金属は研磨組成物中の液相に含まれているのであれば、研磨工程後に半導体基板の洗浄を行うことで比較的容易に除去することが可能であるため、半導体基板に与える影響が少ないからである。 Further, as described above, the pH of the polishing composition of the present invention is 11.0 or more and less than 12.5. In order to adjust the pH of the polishing composition to 11.0 or more and less than 12.5, a pH adjustor can be added to the polishing composition of the present invention. The type of pH adjuster is not particularly limited, and examples thereof include aqueous potassium hydroxide solution, tetramethylammonium hydroxide solution, and ammonia water. The pH adjustor may include an alkali metal such as potassium and an alkaline earth metal such as calcium. This is because if these metals are contained in the liquid phase of the polishing composition, it is possible to remove them relatively easily by cleaning the semiconductor substrate after the polishing step. This is because it has little influence.
また、本発明の研磨組成物は水溶性高分子を含んでも良く、水溶性高分子としてノニオン性界面活性剤、又はアニオン性界面活性剤、あるいはこれらの両方を含むことが好ましい。ノニオン性界面活性剤としては、ポリビニルピロリドン、ポリビニルアルコール、ポリアクリルアミド、ポリエチレングリコール、ポリオキシエチレンアルキルエーテル、及びポリエーテルのうち１種類以上を含有することが好ましい。アニオン性界面活性剤としては、ポリアクリル酸あるいはその塩、ポリスルホン酸あるいはその塩、ポリカルボン酸あるいはその塩のうち１種類以上を含有することが好ましい。 Further, the polishing composition of the present invention may contain a water-soluble polymer, and it is preferable that the water-soluble polymer contains a nonionic surfactant, an anionic surfactant, or both of them. The nonionic surfactant preferably contains at least one of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, polyethylene glycol, polyoxyethylene alkyl ether, and polyether. The anionic surfactant preferably contains at least one of polyacrylic acid or a salt thereof, polysulfonic acid or a salt thereof, polycarboxylic acid or a salt thereof.
研磨組成物中に含まれている水溶性高分子は、被研磨表面及び砥粒であるジルコニウム酸化物表面との相互作用により、酸化ジルコニウムの凝集防止や半導体基板の研磨面の保護等の効果を有する。このような効果によって、半導体基板の表面に研磨によるスクラッチ等の欠陥が発生し難くなる。なお、水溶性高分子の重合度及び分子量は特に制限されず、目的に応じ適宜選択できる。 The water-soluble polymer contained in the polishing composition has an effect of preventing agglomeration of zirconium oxide and protecting the polished surface of the semiconductor substrate due to the interaction with the surface to be polished and the surface of the zirconium oxide which is the abrasive grain. Have. Due to such an effect, defects such as scratches due to polishing are less likely to occur on the surface of the semiconductor substrate. The degree of polymerization and the molecular weight of the water-soluble polymer are not particularly limited and can be appropriately selected depending on the purpose.
水溶性高分子の含有量は研磨組成物全体に対して０．００１〜０．５質量％が好ましく、０．００５〜０．２質量％であることが特に好ましい。水溶性高分子の含有量が０．００１質量％以上であれば、上記のスクラッチの発生の抑制効果が十分に得られる。水溶性高分子の含有量が０．５質量％以下では研磨速度が低下し難いうえに、研磨組成物が発泡し難くなる。 The content of the water-soluble polymer is preferably 0.001 to 0.5% by mass, and particularly preferably 0.005 to 0.2% by mass, based on the whole polishing composition. When the content of the water-soluble polymer is 0.001% by mass or more, the above-described effect of suppressing scratch generation can be sufficiently obtained. When the content of the water-soluble polymer is 0.5% by mass or less, the polishing rate is hard to decrease and the polishing composition is hard to foam.
また、本発明の研磨組成物は、さらに、酸化剤を含むことが好ましい。酸化剤としては、過酸化水素が好適に用いられる。このような酸化剤を含むことにより、半導体基板の表面を酸化でき、研磨をより効果的に促進できる。 Further, the polishing composition of the present invention preferably further contains an oxidizing agent. Hydrogen peroxide is preferably used as the oxidizing agent. By including such an oxidizing agent, the surface of the semiconductor substrate can be oxidized and polishing can be more effectively promoted.
このとき、酸化剤の含有量が研磨組成物全体の０．０１〜１．０質量％であることが好ましい。酸化剤の含有量が研磨組成物に対して０．０１質量％以上であれば、酸化剤による研磨の促進効果を十分に得られる。酸化剤の含有量が研磨組成物に対して１．０質量％以下であれば、化学的研磨作用が強くなり過ぎることが無く、面ダレの発生をより抑制することができる。 At this time, the content of the oxidizing agent is preferably 0.01 to 1.0 mass% of the entire polishing composition. When the content of the oxidizing agent is 0.01% by mass or more based on the polishing composition, the effect of promoting polishing by the oxidizing agent can be sufficiently obtained. When the content of the oxidizing agent is 1.0% by mass or less based on the polishing composition, the chemical polishing action does not become too strong, and the occurrence of surface sagging can be further suppressed.
続いて、上記のような本発明の研磨組成物の製造方法について図１を参照して説明する。 Next, the method for producing the polishing composition of the present invention as described above will be described with reference to FIG.
まず、砥粒として酸化ジルコニウムの粒子を準備する（図１のＳ１）。この酸化ジルコニウムとしては、酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものを準備する。酸化ジルコニウム中の、ジルコニウム以外の金属元素の濃度を測定するには、例えば、ＩＣＰ−ＭＳ分析（誘導結合プラズマ質量分析）を使用すればよい。 First, zirconium oxide particles are prepared as abrasive grains (S1 in FIG. 1). As this zirconium oxide, ones in which the concentrations of the elements of magnesium, aluminum and iron contained in zirconium oxide are each less than 1 ppm are prepared. To measure the concentration of a metal element other than zirconium in zirconium oxide, for example, ICP-MS analysis (inductively coupled plasma mass spectrometry) may be used.
続いて、準備した酸化ジルコニウムを水に添加する（図１のＳ２）。 Subsequently, the prepared zirconium oxide is added to water (S2 in FIG. 1).
続いて、酸化ジルコニウムを水に添加して作製した溶液にｐＨ調整剤を添加することで、溶液のｐＨを１１．０以上１２．５未満に調整する（図１のＳ３）。ｐＨ調整剤の種類は特に限定されず、水酸化カリウム水溶液や水酸化テトラメチルアンモニウム溶液、アンモニア水などが例示される。 Then, the pH of the solution is adjusted to 11.0 or more and less than 12.5 by adding a pH adjusting agent to the solution prepared by adding zirconium oxide to water (S3 in FIG. 1). The type of pH adjuster is not particularly limited, and examples thereof include aqueous potassium hydroxide solution, tetramethylammonium hydroxide solution, and ammonia water.
このようにしてｐＨを調製した後の溶液を用いて研磨組成物を製造する。なお、本発明の研磨組成物の製造方法では、上記の酸化ジルコニウム及びｐＨ調整剤を添加した溶液に、水溶性高分子や酸化剤を更に添加して研磨組成物を作製しても良い。水溶性高分子や酸化剤としては、上述した物質と同様の物質を使用すればよい。 A polishing composition is manufactured using the solution after adjusting the pH in this way. In the method for producing a polishing composition of the present invention, a polishing composition may be prepared by further adding a water-soluble polymer or an oxidizing agent to the solution containing the zirconium oxide and the pH adjusting agent. As the water-soluble polymer and the oxidizing agent, the same substances as those mentioned above may be used.
次に、本発明の研磨組成物を用いた研磨方法を説明する。本発明の研磨組成物は粗研磨である１次研磨及び鏡面研磨である２次研磨のどちらの研磨工程にも好適に用いることができる。また、以下では、半導体基板を片面研磨する場合を例に説明するが、もちろんこれに限定されることはなく、本発明の研磨組成物は両面研磨や面取り部の研磨にも用いることができる。また、特に本発明の研磨方法は単結晶シリコンウェーハの研磨に好適に使用される。 Next, a polishing method using the polishing composition of the present invention will be described. The polishing composition of the present invention can be suitably used in both the polishing step of primary polishing which is rough polishing and the secondary polishing which is mirror polishing. Further, the case where the semiconductor substrate is polished on one side will be described below as an example, but the present invention is not limited to this, and the polishing composition of the present invention can be used for double-side polishing and polishing of a chamfered portion. Further, the polishing method of the present invention is particularly preferably used for polishing a single crystal silicon wafer.
片面研磨装置は、例えば、図２に示すように、研磨パッド４が貼り付けられた定盤３と、研磨組成物供給機構５と、研磨ヘッド２等から構成された片面研磨装置１０とすることができる。
The single-side polishing apparatus is, for example, as shown in FIG. 2, a single-
このような研磨装置１０では、研磨ヘッド２で半導体基板Ｗを保持し、研磨組成物供給機構５から研磨パッド４上に本発明の研磨組成物１を供給するとともに、定盤３と研磨ヘッド２をそれぞれ回転させて半導体基板Ｗの表面を研磨パッド４に摺接させることにより研磨を行う。
In such a
このような本発明の研磨組成物を用いた研磨方法であれば、内周部だけでなく外周部の平坦性も高く、金属不純物による汚染が少ない半導体基板を生産性良く得ることができる。 With such a polishing method using the polishing composition of the present invention, a semiconductor substrate having high flatness not only in the inner peripheral portion but also in the outer peripheral portion and less contaminated by metal impurities can be obtained with high productivity.
以下、本発明の実施例及び比較例を示して本発明をより具体的に説明するが、本発明はこれら実施例に限定されるものではない。 Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples.
（実施例１）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを、含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、この溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のようにして、研磨組成物を作製した。
(Example 1)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of this solution became 11.5. A polishing composition was prepared as described above.
（実施例２）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量６０００であるポリエチレングリコールを含有量が０．０７質量％となるよう添加した。さらに、溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のようにして、研磨組成物を作製した。
(Example 2)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyethylene glycol having an average molecular weight of 6000 was added to pure water in which zirconium oxide was dispersed so that the content thereof was 0.07% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 11.5. A polishing composition was prepared as described above.
（実施例３）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均重合度１０００、けん化度８０〜９０ｍｏｌ％のポリビニルアルコールを、含有量が０．０７質量％となるよう添加した。さらに、過酸化水素を、含有量が１．０質量％となるよう添加した。その後、溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のようにして、研磨組成物を作製した。
(Example 3)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyvinyl alcohol having an average degree of polymerization of 1000 and a degree of saponification of 80 to 90 mol% was added to pure water in which zirconium oxide was dispersed so that the content was 0.07% by mass. Further, hydrogen peroxide was added so that the content was 1.0% by mass. Then, a potassium hydroxide solution was added so that the pH of the solution became 11.5. A polishing composition was prepared as described above.
（実施例４）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１１．０となるように水酸化カリウム溶液を加えた。以上のようにして、研磨組成物を作製した。
(Example 4)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Furthermore, a potassium hydroxide solution was added so that the pH of the solution became 11.0. A polishing composition was prepared as described above.
（実施例５）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１２．４となるように水酸化カリウム溶液を加えた。以上のようにして、研磨組成物を作製した。
(Example 5)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 12.4. A polishing composition was prepared as described above.
（比較例１）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径３４ｎｍのコロイダルシリカを含有量が１．０質量％となるよう純水に分散させた。次に、コロイダルシリカを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のように、砥粒として、コロイダルシリカを使用した研磨組成物を作製した。
(Comparative Example 1)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The colloidal silica having a primary particle diameter of 34 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which colloidal silica was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 11.5. As described above, a polishing composition using colloidal silica as the abrasive grain was prepared.
（比較例２）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度がＭｇ：２０ｐｐｍ、Ｆｅ：１８ｐｐｍ、Ａｌ：１１ｐｐｍ、Ｔｉ：５ｐｐｍ、その他の金属元素がそれぞれ１ｐｐｍ未満である１次粒子径３０ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のようにして、酸化ジルコニウム中のＭｇ、Ｆｅ、Ａｌ、及びＴｉの元素の濃度が１ｐｐｍ以上である研磨組成物を作製した。
(Comparative example 2)
The metal impurity concentration was measured by ICP-MS analysis with sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt as the measurement elements, and each metal impurity concentration was Mg. : 20 ppm, Fe: 18 ppm, Al: 11 ppm, Ti: 5 ppm, and zirconium oxide having a primary particle diameter of 30 nm and other metal elements each less than 1 ppm are dispersed in pure water to a content of 1.0% by mass. It was Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 11.5. As described above, a polishing composition in which the concentration of Mg, Fe, Al and Ti elements in zirconium oxide was 1 ppm or more was prepared.
（比較例３）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度がＦｅ：１ｐｐｍ、その他の金属元素がそれぞれ１ｐｐｍ未満である１次粒子径３０ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１１．５となるように水酸化カリウム溶液を加えた。以上のようにして、酸化ジルコニウム中のＦｅの元素の濃度が１ｐｐｍ以上である研磨組成物を作製した。
(Comparative example 3)
The metal impurity concentration was measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration was Fe. 1 ppm, and zirconium oxide having a primary particle diameter of 30 nm and other metal elements each less than 1 ppm were dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 11.5. As described above, a polishing composition was prepared in which the concentration of Fe element in zirconium oxide was 1 ppm or more.
（比較例４）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１０．５となるように水酸化カリウム溶液を加えた。以上のようにして、ｐＨが１１．０未満である研磨組成物を作製した。
(Comparative Example 4)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added so that the content was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 10.5. As described above, a polishing composition having a pH of less than 11.0 was prepared.
（比較例５）
ＩＣＰ−ＭＳ分析により測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして金属不純物濃度を測定し、各金属不純物濃度が１ｐｐｍ未満であった１次粒子径２６ｎｍの酸化ジルコニウムを含有量が１．０質量％となるよう純水に分散させた。次に、酸化ジルコニウムを分散させた純水に、平均分子量１００００であるポリアクリル酸を含有量が０．０５質量％となるよう添加した。さらに、溶液のｐＨが１２．８となるように水酸化カリウム溶液を加えた。以上のようにして、ｐＨが１２．５以上である研磨組成物を作製した。
(Comparative example 5)
The metal impurity concentration is measured by ICP-MS analysis as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc, lead, and cobalt, and each metal impurity concentration is 1 ppm. The zirconium oxide having a primary particle diameter of 26 nm, which was less than the above, was dispersed in pure water so that the content was 1.0% by mass. Next, polyacrylic acid having an average molecular weight of 10,000 was added to pure water in which zirconium oxide was dispersed so that the content of polyacrylic acid was 0.05% by mass. Further, a potassium hydroxide solution was added so that the pH of the solution became 12.8. As described above, a polishing composition having a pH of 12.5 or higher was produced.
実施例１〜５及び比較例１〜５の研磨組成物を用いて下記の研磨条件により直径１２インチ（３００ｍｍ）の単結晶シリコン基板の片面研磨を行った。研磨装置はＰｏｌｉ−７６２（Ｇ＆Ｐ Ｔｅｃｈｎｏｌｏｇｙ， Ｉｎｃ．製）、研磨パッドとしてＩＣ１０００（ニッタ・ハース（株）製）を使用した。被研磨基板に加える加重を１９３ｇ／ｃｍ２とし、定盤回転数を７０ｒｐｍ、ヘッド回転数を７０ｒｐｍとし、研磨組成物の供給量を１００ｍＬ／ｍｉｎとした。 Using the polishing compositions of Examples 1-5 and Comparative Examples 1-5, single-sided polishing of single-crystal silicon substrates having a diameter of 12 inches (300 mm) was performed under the following polishing conditions. The polishing apparatus used was Poli-762 (manufactured by G&P Technology, Inc.), and IC1000 (manufactured by Nitta Haas Co., Ltd.) was used as a polishing pad. The load applied to the substrate to be polished was 193 g/cm 2 , the platen rotation speed was 70 rpm, the head rotation speed was 70 rpm, and the polishing composition supply rate was 100 mL/min.
研磨終了後、研磨速度を算出した。また、外周除外領域を２ｍｍ、サイトサイズを２５ｍｍ×２５ｍｍとして研磨後の半導体基板のＳＦＱＲを測定した。また研磨後の半導体基板を公知であるＳＣ−１（２９％アンモニア水、３０％過酸化水素水、純水の混合溶液、体積比率 アンモニア水：過酸化水素水：純水＝１：１：１０、７５℃、５分浸漬）及びＳＣ−２（３０％塩酸、３０％過酸化水素水、純水の混合溶液、体積比率 塩酸：過酸化水素水：純水＝１：１：１０、７５℃、５分浸漬）によるＲＣＡ洗浄を行なった後、ＴＲＥＸ（全反射蛍光Ｘ線分析）により、測定元素をナトリウム、マグネシウム、アルミニウム、カリウム、カルシウム、チタン、クロム、鉄、マンガン、ニッケル、銅、亜鉛、鉛、及びコバルトとして基板表面の任意の５点を分析し金属不純物による汚染の確認を行った。 After the polishing was completed, the polishing rate was calculated. Further, the SFQR of the semiconductor substrate after polishing was measured with the outer peripheral excluded region being 2 mm and the site size being 25 mm×25 mm. Further, the polished semiconductor substrate is a known SC-1 (29% ammonia water, 30% hydrogen peroxide water, pure water mixed solution, volume ratio ammonia water:hydrogen peroxide water:pure water=1:1:10. , 75° C., 5 minutes immersion) and SC-2 (30% hydrochloric acid, 30% hydrogen peroxide solution, pure water mixed solution, volume ratio hydrochloric acid:hydrogen peroxide water:pure water=1:1:10, 75° C. After RCA cleaning by immersion for 5 minutes), TREX (total reflection X-ray fluorescence analysis) was performed to determine the measurement element as sodium, magnesium, aluminum, potassium, calcium, titanium, chromium, iron, manganese, nickel, copper, zinc. Any five points on the surface of the substrate were analyzed as lead, lead, and cobalt to confirm contamination with metal impurities.
研磨速度、ＳＦＱＲの最大値、単結晶シリコン基板上の金属不純物の濃度について表１にまとめた。不純物は各測定元素の検出値について下記の基準に基づいた評価結果を示した。
○： １．０×１０１０ａｔｏｍ／ｃｍ２未満
△： １．０×１０１０以上１．０×１０１１ａｔｏｍ／ｃｍ２未満
×： １．０×１０１１ａｔｏｍ／ｃｍ２以上
The polishing rate, the maximum value of SFQR, and the concentration of metal impurities on the single crystal silicon substrate are summarized in Table 1. The impurities showed the evaluation results based on the following criteria for the detected values of each measured element.
◯: less than 1.0×10 10 atoms/cm 2 Δ: 1.0×10 10 or more but less than 1.0×10 11 atoms/cm 2 ×: 1.0×10 11 atoms/cm 2 or more
表１に示すように、実施例１〜５では、研磨後の半導体基板の表面から検出された各金属不純物の濃度は、１．０×１０１０ａｔｏｍ／ｃｍ２未満となり、研磨による半導体基板の不純物汚染を抑制することができた。また、実施例１〜５では、十分な研磨速度が得られ、且つ、特に半導体基板の外周部の面ダレが少ないためＳＦＱＲの最大値も低く抑えられ、良好な平坦性が得られた。 As shown in Table 1, in Examples 1 to 5, the concentration of each metal impurity detected from the surface of the semiconductor substrate after polishing was less than 1.0×10 10 atom/cm 2 , which indicates that the semiconductor substrate Impurity contamination could be suppressed. Further, in Examples 1 to 5, a sufficient polishing rate was obtained, and since the surface sagging of the outer peripheral portion of the semiconductor substrate was particularly small, the maximum value of SFQR was suppressed to be low, and good flatness was obtained.
一方、表１に示すように、比較例１のように、砥粒としてコロイダルシリカを使用した場合、実施例に比べ研磨速度が遅いうえに、ＳＦＱＲの最大値が大きく、平坦性が悪化した。また、比較例２、３のように、ジルコニウム以外の金属元素の濃度が１ｐｐｍ以上である酸化ジルコニウムを砥粒として使用すると、研磨後の半導体基板の表面から金属不純物が１．０×１０１０ａｔｏｍ／ｃｍ２以上の濃度で検出され、実施例と比較して金属不純物による汚染が悪化した。また、比較例４のように、研磨組成物のｐＨが１１．０未満であると、化学的研磨作用が十分に得られず、研磨速度が低下した。また、比較例５のように、研磨組成物のｐＨが１２．５以上であると、化学的研磨作用が強くなりすぎて、面ダレを促進し、ＳＦＱＲの最大値が著しく大きくなった。 On the other hand, as shown in Table 1, when colloidal silica was used as the abrasive grains as in Comparative Example 1, the polishing rate was slower than in Examples, and the maximum SFQR value was large, resulting in poor flatness. Further, as in Comparative Examples 2 and 3, when zirconium oxide having a metal element concentration other than zirconium of 1 ppm or more is used as abrasive grains, metal impurities are 1.0×10 10 atom from the surface of the semiconductor substrate after polishing. It was detected at a concentration of /cm 2 or more, and the contamination with metal impurities was worse than in the examples. Further, as in Comparative Example 4, when the pH of the polishing composition was less than 11.0, the chemical polishing action was not sufficiently obtained, and the polishing rate decreased. Further, as in Comparative Example 5, when the pH of the polishing composition was 12.5 or more, the chemical polishing action became too strong, surface sagging was promoted, and the maximum value of SFQR was significantly increased.
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。 The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the invention having substantially the same configuration as the technical idea described in the scope of the claims of the present invention and exhibiting the same action and effect is the present invention It is included in the technical scope of.
１…研磨組成物、 ２…研磨ヘッド、 ３…定盤、
４…研磨パッド、 ５…研磨組成物供給機構、
１０…片面研磨装置、
Ｗ…半導体基板。
1... Polishing composition, 2... Polishing head, 3... Surface plate,
4... polishing pad, 5... polishing composition supply mechanism,
10... Single-side polishing machine,
W... Semiconductor substrate.
Claims (8)
ｐＨが１１．０以上１２．５未満のものであり、前記酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものであり、
さらに、水溶性高分子としてノニオン性界面活性剤、又はアニオン性界面活性剤、あるいはこれらの両方が含まれ、
前記ノニオン性界面活性剤として、ポリビニルピロリドン、ポリビニルアルコール、ポリアクリルアミド、ポリエチレングリコール、及びポリエーテルのうち１種類以上を含有し、
前記アニオン性界面活性剤として、ポリアクリル酸あるいはその塩、及びポリカルボン酸あるいはその塩のうち１種類以上を含有し、
前記研磨組成物を用いて単結晶シリコン基板を研磨した場合、該単結晶シリコン基板の直径を３００ｍｍとし、前記単結晶シリコン基板に加える加重を１９３ｇ／ｃｍ ２ とし、定盤回転数を７０ｒｐｍ、ヘッド回転数を７０ｒｐｍとする条件下で、研磨速度が０．２０μｍ／ｍｉｎ以上であり、前記単結晶シリコン基板のＳＦＱＲの最大値が６３ｎｍ以下となるものであり、
前記酸化ジルコニウムの平均１次粒子径が５ｎｍ以上１００ｎｍ未満であり、
前記酸化ジルコニウムの１次粒子の形状が球形であることを特徴とする研磨組成物。 A polishing composition containing zirconium oxide as abrasive grains,
pH is 11.0 or more and less than 12.5, and the concentration of each element of magnesium, aluminum and iron contained in the zirconium oxide is less than 1 ppm,
Further, the water-soluble polymer contains a nonionic surfactant, an anionic surfactant, or both,
As the nonionic surfactant, one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, polyethylene glycol, and polyether are contained,
As the anionic surfactant, containing one or more of polyacrylic acid or a salt thereof and polycarboxylic acid or a salt thereof ,
When a single crystal silicon substrate is polished using the polishing composition, the diameter of the single crystal silicon substrate is 300 mm, the load applied to the single crystal silicon substrate is 193 g/cm 2 , the platen rotation speed is 70 rpm, and the head is Under the condition that the rotation speed is 70 rpm, the polishing rate is 0.20 μm/min or more, and the maximum value of SFQR of the single crystal silicon substrate is 63 nm or less.
The average primary particle diameter of the zirconium oxide is 5 nm or more and less than 100 nm,
The polishing composition, wherein the shape of the primary particles of zirconium oxide is spherical .
前記酸化ジルコニウムとして、前記酸化ジルコニウム中に含まれるマグネシウム、アルミニウム及び鉄の元素の濃度がそれぞれ１ｐｐｍ未満のものを準備する工程と、
前記準備した酸化ジルコニウムを水に添加する工程と、
前記酸化ジルコニウムを添加した溶液にｐＨ調整剤を添加することで、前記溶液のｐＨを１１．０以上１２．５未満に調整する工程と、
前記溶液に水溶性高分子を添加する工程とを含み、
前記ｐＨを調製した後の溶液を用いて研磨組成物を製造し、
前記水溶性高分子としてノニオン性界面活性剤、又はアニオン性界面活性剤、あるいはこれらの両方を用い、
前記ノニオン性界面活性剤として、ポリビニルピロリドン、ポリビニルアルコール、ポリアクリルアミド、ポリエチレングリコール、及びポリエーテルのうち１種類以上を用い、
前記アニオン性界面活性剤として、ポリアクリル酸あるいはその塩、及びポリカルボン酸あるいはその塩のうち１種類以上を用い、
前記研磨組成物を用いて単結晶シリコン基板を研磨した場合、該単結晶シリコン基板の直径を３００ｍｍとし、前記単結晶シリコン基板に加える加重を１９３ｇ／ｃｍ ２ とし、定盤回転数を７０ｒｐｍ、ヘッド回転数を７０ｒｐｍとする条件下で、研磨速度が０．２０μｍ／ｍｉｎ以上であり、前記単結晶シリコン基板のＳＦＱＲの最大値が６３ｎｍ以下となるものであり、
前記酸化ジルコニウムの平均１次粒子径が５ｎｍ以上１００ｎｍ未満であり、
前記酸化ジルコニウムの１次粒子の形状が球形であることを特徴とする研磨組成物の製造方法。
A method for producing a polishing composition containing zirconium oxide as abrasive grains,
A step of preparing, as the zirconium oxide, one in which the concentration of each element of magnesium, aluminum and iron contained in the zirconium oxide is less than 1 ppm,
A step of adding the prepared zirconium oxide to water,
Adjusting the pH of the solution to 11.0 or more and less than 12.5 by adding a pH adjusting agent to the solution containing zirconium oxide;
A step of adding a water-soluble polymer to the solution,
A polishing composition is produced using the solution after adjusting the pH,
As the water-soluble polymer, a nonionic surfactant, or an anionic surfactant, or both are used,
As the nonionic surfactant, one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylamide, polyethylene glycol, and polyether are used,
As the anionic surfactant, one or more of polyacrylic acid or a salt thereof and polycarboxylic acid or a salt thereof is used ,
When a single crystal silicon substrate is polished using the polishing composition, the diameter of the single crystal silicon substrate is 300 mm, the load applied to the single crystal silicon substrate is 193 g/cm 2 , the platen rotation speed is 70 rpm, and the head is Under the condition that the rotation speed is 70 rpm, the polishing rate is 0.20 μm/min or more, and the maximum value of SFQR of the single crystal silicon substrate is 63 nm or less.
The average primary particle diameter of the zirconium oxide is 5 nm or more and less than 100 nm,
The method for producing a polishing composition, wherein the shape of the primary particles of zirconium oxide is spherical .
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| JP2001269859A (en) * | 2000-03-27 | 2001-10-02 | Jsr Corp | Aqueous dispersing element for polishing chemical machine |
| JP2004266155A (en) * | 2003-03-03 | 2004-09-24 | Jsr Corp | Water dispersed element for chemical mechanical polishing and chemical mechanical polishing method using the same and method for manufacturing semiconductor device |
| WO2007116770A1 (en) * | 2006-04-03 | 2007-10-18 | Jsr Corporation | Aqueous dispersion for chemical mechanical polishing, chemical mechanical polishing method, and kit for preparing aqueous dispersion for chemical mechanical polishing |
| JP2008186898A (en) * | 2007-01-29 | 2008-08-14 | Nissan Chem Ind Ltd | Composition for polishing |
| JP2010192556A (en) * | 2009-02-17 | 2010-09-02 | Fujifilm Corp | Polishing solution for metal, and chemical mechanical polishing method |
| KR20180135113A (en) * | 2011-01-27 | 2018-12-19 | 가부시키가이샤 후지미인코퍼레이티드 | Polishing material and polishing composition |
| JP2013158884A (en) * | 2012-02-06 | 2013-08-19 | Raytex Corp | Substrate polishing device |
| KR101406763B1 (en) * | 2012-12-04 | 2014-06-19 | 주식회사 케이씨텍 | Slurry composition and additive composition |
| JP2015029001A (en) * | 2013-07-30 | 2015-02-12 | 日立化成株式会社 | Polishing liquid for cmp, and polishing method |
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