JP7523291B2 - Polishing composition, polishing method, and method for producing semiconductor substrate - Google Patents
Polishing composition, polishing method, and method for producing semiconductor substrate Download PDFInfo
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- JP7523291B2 JP7523291B2 JP2020153877A JP2020153877A JP7523291B2 JP 7523291 B2 JP7523291 B2 JP 7523291B2 JP 2020153877 A JP2020153877 A JP 2020153877A JP 2020153877 A JP2020153877 A JP 2020153877A JP 7523291 B2 JP7523291 B2 JP 7523291B2
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- polishing composition
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- 238000005498 polishing Methods 0.000 title claims description 294
- 239000000203 mixture Substances 0.000 title claims description 122
- 238000000034 method Methods 0.000 title claims description 27
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- 239000004065 semiconductor Substances 0.000 title claims description 9
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- 150000001875 compounds Chemical class 0.000 claims description 42
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- 125000004432 carbon atom Chemical group C* 0.000 claims description 17
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 7
- 229910052814 silicon oxide Inorganic materials 0.000 description 32
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Landscapes
- Mechanical Treatment Of Semiconductor (AREA)
Description
本発明は、研磨用組成物、研磨方法、および半導体基板の製造方法に関する。 The present invention relates to a polishing composition, a polishing method, and a method for manufacturing a semiconductor substrate.
近年、LSI(Large Scale Integration)の高集積化、高性能化に伴って新たな微細加工技術が開発されている。化学機械研磨(Chemical Mechanical Polishing;CMP)法もその一つであり、LSI製造工程、特に多層配線形成工程における層間絶縁膜の平坦化、金属プラグ形成、埋め込み配線(ダマシン配線)形成において頻繁に利用される技術である。 In recent years, new microfabrication technologies have been developed in response to the increasing integration and performance of LSI (Large Scale Integration). Chemical Mechanical Polishing (CMP) is one such technology, and it is frequently used in the LSI manufacturing process, particularly in the multilayer wiring formation process, for planarizing the interlayer insulating film, forming metal plugs, and forming embedded wiring (damascene wiring).
当該CMPは、半導体製造における各工程に適用されてきており、その一態様として、例えばトランジスタ作製におけるゲート形成工程への適用が挙げられる。トランジスタ作製の際には、シリコン、シリコン酸化膜(酸化シリコン)、多結晶シリコン(ポリシリコン)やシリコン窒化物(窒化ケイ素)といったSi含有材料を研磨することがあり、トランジスタの構造によっては、各Si含有材料の研磨レートを制御することが求められている。 CMP has been applied to various processes in semiconductor manufacturing, and one example of this is the gate formation process in transistor fabrication. When fabricating a transistor, Si-containing materials such as silicon, silicon oxide film (silicon oxide), polycrystalline silicon (polysilicon), and silicon nitride (silicon nitride) may be polished, and depending on the transistor structure, it is necessary to control the polishing rate of each Si-containing material.
例えば、特許文献1には、砥粒として酸化アルミニウム、および水を含み、pHが10.5~11.5であることを特徴とするポリシリコン用研磨材が開示されている。 For example, Patent Document 1 discloses an abrasive for polysilicon that contains aluminum oxide as abrasive grains and water and has a pH of 10.5 to 11.5.
最近、ポリシリコンと窒化ケイ素とを共に含む基板が用いられるようになってきており、このような基板において、ポリシリコンを選択的に研磨するという要求が高まってきている。しかしながら、特許文献1の技術では、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)が低いという問題があった。 Recently, substrates containing both polysilicon and silicon nitride have come into use, and there is an increasing demand for selective polishing of polysilicon on such substrates. However, the technology of Patent Document 1 has a problem in that the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon nitride is low.
したがって、本発明の目的は、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(すなわち、選択比)を向上できる手段を提供することにある。 Therefore, the object of the present invention is to provide a means for improving the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (i.e., the selectivity ratio).
また、本発明の他の目的は、ポリシリコンの研磨速度が十分に高い研磨用組成物を提供することにある。 Another object of the present invention is to provide a polishing composition that has a sufficiently high polishing rate for polysilicon.
上記課題を解決すべく、本発明者は鋭意研究を積み重ねた。その結果、正のゼータ電位を有する砥粒と、式(1):N(R1)(R2)-C(=O)-N(R3)(R4)(式中、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す)で示される構造を有する化合物と、を含み、pHが6.0未満である、研磨用組成物により、上記課題の少なくとも一つが解決できることを見出し、本発明を完成させるに至った。 In order to solve the above problems, the present inventors have conducted extensive research and have found that at least one of the above problems can be solved by a polishing composition that contains an abrasive having a positive zeta potential and a compound having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms), and has a pH of less than 6.0, thereby completing the present invention.
本発明の研磨用組成物によれば、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比を向上できる。また、本発明によれば、ポリシリコンの研磨速度が十分に高い研磨用組成物が提供できる。 The polishing composition of the present invention can improve the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride. Furthermore, the present invention can provide a polishing composition that has a sufficiently high polishing rate of polysilicon.
本発明は、正のゼータ電位を有する砥粒と、式(1):N(R1)(R2)-C(=O)-N(R3)(R4)(式中、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す)で示される構造を有する化合物と、を含み、pHが6.0未満である、研磨用組成物に関する。かような構成を有する本発明の研磨用組成物によれば、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比が十分に高い(選択比が高い)という効果が得られる。また、本発明の研磨用組成物によれば、ポリシリコンの研磨速度が十分に高いという効果が得られる。なお、本明細書において、式(1):N(R1)(R2)-C(=O)-N(R3)(R4)(式中、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す)で示される構造を有する化合物を、単に「式(1)の化合物」とも称する。 The present invention relates to a polishing composition comprising an abrasive having a positive zeta potential and a compound having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms), and having a pH of less than 6.0. The polishing composition of the present invention having such a configuration provides the effect that the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride is sufficiently high (high selectivity). Furthermore, the polishing composition of the present invention provides the effect that the polishing rate of polysilicon is sufficiently high. In this specification, a compound having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms) is also simply referred to as a "compound of formula (1)".
上記のような効果が得られるメカニズムは、以下の通りであると考えられる。ただし、下記メカニズムはあくまで推測であり、これによって本発明の範囲が制限されることはない。 The mechanism by which the above-mentioned effects are obtained is believed to be as follows. However, the following mechanism is merely speculation and does not limit the scope of the present invention.
研磨用組成物に含まれる式(1)の化合物は、=N-C(=O)-N=部分を有するが、この部分の窒素原子に存在する非共有電子対が高い電子供与性(求核性)を有する。加えて、研磨用組成物に含まれる式(1)の化合物は、=N-C(=O)-N=部分の両末端に少なくとも1個のアルキル基が存在する。このアルキル基の存在により、電子がよりスムーズに動くことが可能になるため、電子供与性(求核性)がより高まる。この非共有電子対が、ポリシリコン表面に求核反応することにより、ポリシリコンのケイ素-ケイ素結合は弱くなる。これにより、ポリシリコンの膜表面(すなわち研磨面)が脆化し、砥粒による掻き取りが容易になり、ポリシリコンの研磨速度が向上すると考えられる。また、研磨対象物がポリシリコンとともに酸化ケイ素を含む場合、ポリシリコンの研磨速度と酸化ケイ素の研磨速度とが等しくなる(酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)は1に近くなる)。 The compound of formula (1) contained in the polishing composition has a =N-C(=O)-N= portion, and the unshared electron pair present in the nitrogen atom of this portion has high electron donating (nucleophilic) properties. In addition, the compound of formula (1) contained in the polishing composition has at least one alkyl group at both ends of the =N-C(=O)-N= portion. The presence of this alkyl group allows electrons to move more smoothly, so the electron donating (nucleophilic) properties are further increased. This unshared electron pair undergoes a nucleophilic reaction with the polysilicon surface, weakening the silicon-silicon bond of the polysilicon. This makes the polysilicon film surface (i.e., the polishing surface) brittle, making it easier to scrape off with abrasive grains, and is thought to improve the polishing rate of the polysilicon. In addition, when the object to be polished contains silicon oxide together with polysilicon, the polishing rate of the polysilicon and the polishing rate of the silicon oxide become equal (the ratio (selectivity) of the polishing rate of the polysilicon to the polishing rate of the silicon oxide becomes close to 1).
さらに、研磨対象物がポリシリコンとともに窒化ケイ素を含む場合、窒化ケイ素に対しての求核付加はほとんど起きないため、窒化ケイ素の研磨速度は低く抑えられたままである。よって、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)が向上すると考えられる。 Furthermore, when the object to be polished contains silicon nitride as well as polysilicon, nucleophilic addition to silicon nitride hardly occurs, so the polishing rate of silicon nitride remains low. Therefore, it is believed that the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (selectivity ratio) improves.
また、本発明の研磨用組成物を用いてポリシリコンを研磨する場合において、ポリシリコン表面のゼータ電位は負である。本発明の研磨用組成物に含まれる砥粒のゼータ電位は正であることから、砥粒とポリシリコン表面との間に引力が生じ、砥粒は研磨面であるポリシリコン表面に付着しやすくなる。これにより、砥粒がポリシリコン表面に対して有意に近接することができ、砥粒によるポリシリコン表面の掻き取りがさらに容易になり、さらに効率的なポリシリコンの研磨が実現できるものと推測される。よって、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(窒化ケイ素に対するポリシリコンの選択比)が向上すると考えられる。 In addition, when polysilicon is polished using the polishing composition of the present invention, the zeta potential of the polysilicon surface is negative. Since the zeta potential of the abrasive grains contained in the polishing composition of the present invention is positive, an attractive force is generated between the abrasive grains and the polysilicon surface, and the abrasive grains are likely to adhere to the polysilicon surface, which is the polishing surface. This allows the abrasive grains to come significantly closer to the polysilicon surface, making it even easier for the abrasive grains to scrape off the polysilicon surface, and it is presumed that more efficient polishing of polysilicon can be achieved. Therefore, it is believed that the ratio of the polishing speed of polysilicon to the polishing speed of silicon nitride (selectivity ratio of polysilicon to silicon nitride) is improved.
一方、本発明の研磨用組成物を用いて窒化ケイ素を研磨する場合において、窒化ケイ素表面のゼータ電位は正であり、正のゼータ電位を有する砥粒との間に斥力が生じ、砥粒は窒化ケイ素表面に近づきにくくなる。このことから、砥粒による窒化ケイ素表面の掻き取りは起こりにくく、窒化ケイ素の研磨速度は低いままである。よって、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)およびポリシリコンの研磨速度が向上すると考えられる。 On the other hand, when silicon nitride is polished using the polishing composition of the present invention, the zeta potential of the silicon nitride surface is positive, and a repulsive force is generated between the silicon nitride surface and the abrasive grains, which have a positive zeta potential, making it difficult for the abrasive grains to approach the silicon nitride surface. As a result, the abrasive grains are unlikely to scrape off the silicon nitride surface, and the polishing rate of silicon nitride remains low. Therefore, it is believed that the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride and the polishing rate of polysilicon are improved.
以下、本発明の実施形態を説明する。なお、本発明は、以下の実施形態のみには限定されない。 The following describes an embodiment of the present invention. Note that the present invention is not limited to the following embodiment.
本明細書において、特記しない限り、操作および物性等の測定は室温(20℃以上25℃以下)/相対湿度40%RH以上50%RH以下の条件で行う。 Unless otherwise specified in this specification, operations and measurements of physical properties are performed at room temperature (20°C or higher and 25°C or lower) and at a relative humidity of 40% RH or higher and 50% RH or lower.
[研磨対象物]
本発明に係る研磨対象物は、特に制限されず、例えば、ポリシリコン、窒化ケイ素、炭窒化ケイ素(SiCN)、酸化ケイ素、金属、SiGe等が挙げられる。
[Polished object]
The object to be polished according to the present invention is not particularly limited, and examples thereof include polysilicon, silicon nitride, silicon carbonitride (SiCN), silicon oxide, metal, SiGe, and the like.
酸化ケイ素を含む研磨対象物の例としては、例えば、オルトケイ酸テトラエチルを前駆体として使用して生成されるTEOSタイプ酸化ケイ素面(以下、単に「TEOS」とも称する)、HDP(High Density Plasma)膜、USG(Undoped Silicate Glass)膜、PSG(Phosphorus Silicate Glass)膜、BPSG(Boron-Phospho Silicate Glass)膜、RTO(Rapid Thermal Oxidation)膜等が挙げられる。 Examples of polishing objects containing silicon oxide include TEOS-type silicon oxide surfaces (hereinafter simply referred to as "TEOS") produced using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma) films, USG (Undoped Silicate Glass) films, PSG (Phosphorus Silicate Glass) films, BPSG (Boron-Phospho Silicate Glass) films, and RTO (Rapid Thermal Oxidation) films.
上記金属としては、例えば、タングステン、銅、アルミニウム、コバルト、ハフニウム、ニッケル、金、銀、白金、パラジウム、ロジウム、ルテニウム、イリジウム、オスミウム等が挙げられる。 Examples of the above metals include tungsten, copper, aluminum, cobalt, hafnium, nickel, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium.
これらの中でも、ポリシリコンを含む研磨対象物が好ましい。よって、本発明の好ましい一実施形態によれば、研磨用組成物は、ポリシリコンを含む研磨対象物を研磨するために用いられる。 Among these, objects to be polished that contain polysilicon are preferred. Therefore, according to a preferred embodiment of the present invention, the polishing composition is used to polish objects to be polished that contain polysilicon.
また、上記したように、特にポリシリコンと窒化ケイ素とを含む研磨対象物に本発明の研磨用組成物を適用した場合、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)が向上するという効果が得られる。したがって、本発明の他の好ましい実施形態によれば、研磨用組成物は、窒化ケイ素に対するポリシリコンの選択的な研磨に用いられる。 As described above, when the polishing composition of the present invention is applied to an object to be polished that contains polysilicon and silicon nitride, the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (selectivity) is improved. Therefore, according to another preferred embodiment of the present invention, the polishing composition is used for selective polishing of polysilicon relative to silicon nitride.
[砥粒]
本発明に係る研磨用組成物中に含まれる砥粒は、研磨対象物を機械的に研磨する作用を有し、研磨用組成物による研磨対象物の研磨速度を向上させる。
[Abrasive grain]
The abrasive grains contained in the polishing composition of the present invention have the effect of mechanically polishing an object to be polished, and improve the polishing rate of the object to be polished by the polishing composition.
本発明に係る砥粒は、pH6.0未満の研磨用組成物中で正のゼータ電位を有する。pH6.0未満の研磨用組成物中で0以下のゼータ電位を有する砥粒を用いる場合、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)が低下する。また、ポリシリコンの研磨速度が低下する。 The abrasive grains according to the present invention have a positive zeta potential in a polishing composition having a pH of less than 6.0. When using an abrasive grains having a zeta potential of 0 or less in a polishing composition having a pH of less than 6.0, the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride decreases. In addition, the polishing rate of polysilicon decreases.
研磨用組成物中の砥粒のゼータ電位の下限は、10mV以上が好ましく、10mV超がより好ましく、20mV以上がさらに好ましく、25mV以上が特に好ましい。また、研磨用組成物中の砥粒のゼータ電位の上限は、40mV以下が好ましく、40mV未満がより好ましく、35mV以下がさらに好ましく、35mV未満が特に好ましい。また、すなわち、研磨用組成物中の砥粒のゼータ電位は、10mV以上40mV以下が好ましく、10mV超40mV未満がより好ましく、20mV以上35mV以下がさらに好ましく、25mV以上35mV未満が特に好ましい。 The lower limit of the zeta potential of the abrasive grains in the polishing composition is preferably 10 mV or more, more preferably more than 10 mV, even more preferably 20 mV or more, and particularly preferably 25 mV or more. The upper limit of the zeta potential of the abrasive grains in the polishing composition is preferably 40 mV or less, more preferably less than 40 mV, even more preferably 35 mV or less, and particularly preferably less than 35 mV. In other words, the zeta potential of the abrasive grains in the polishing composition is preferably 10 mV or more and 40 mV or less, more preferably more than 10 mV and less than 40 mV, even more preferably 20 mV or more and 35 mV or less, and particularly preferably 25 mV or more and less than 35 mV.
上記のようなゼータ電位を有する砥粒であれば、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより向上させることができる。また、上記のようなゼータ電位を有する砥粒であれば、ポリシリコンの研磨速度と酸化ケイ素の研磨速度とをより等しくすることができる(酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより1に近づける)。 Abrasive grains having the above-mentioned zeta potential can further improve the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon nitride. In addition, abrasive grains having the above-mentioned zeta potential can make the polishing speed of polysilicon and the polishing speed of silicon oxide more equal (the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon oxide can be brought closer to 1).
本明細書において、砥粒のゼータ電位は、実施例に記載の方法によって測定される値である。砥粒のゼータ電位は、砥粒が有するカチオン性基の量、研磨用組成物のpH等により調整することができる。 In this specification, the zeta potential of the abrasive grains is a value measured by the method described in the Examples. The zeta potential of the abrasive grains can be adjusted by the amount of cationic groups contained in the abrasive grains, the pH of the polishing composition, etc.
本発明の研磨用組成物において、砥粒の種類としては、例えば、カチオン変性シリカ粒子、アルミナ粒子、ジルコニア粒子、チタニア粒子、セリア粒子等の金属酸化物が挙げられる。該砥粒は、単独でもまたは2種以上組み合わせても用いることができる。該砥粒は、それぞれ市販品を用いてもよいし合成品を用いてもよい。 In the polishing composition of the present invention, the types of abrasive grains include, for example, metal oxides such as cation-modified silica particles, alumina particles, zirconia particles, titania particles, and ceria particles. The abrasive grains can be used alone or in combination of two or more kinds. The abrasive grains may be either commercially available products or synthetic products.
砥粒は、カチオン変性シリカ粒子(カチオン性基を有するシリカ粒子)が好ましく、カチオン変性コロイダルシリカ粒子(カチオン性基を有するコロイダルシリカ粒子)がより好ましい。 The abrasive grains are preferably cation-modified silica particles (silica particles having cationic groups), and more preferably cation-modified colloidal silica particles (colloidal silica particles having cationic groups).
コロイダルシリカの製造方法としては、ケイ酸ソーダ法、ゾルゲル法が挙げられ、いずれの製造方法で製造されたコロイダルシリカであっても、本発明の砥粒として好適に用いられる。しかしながら、金属不純物低減の観点から、ゾルゲル法により製造されたコロイダルシリカが好ましい。ゾルゲル法によって製造されたコロイダルシリカは、半導体中に拡散性のある金属不純物や塩化物イオン等の腐食性イオンの含有量が少ないため好ましい。ゾルゲル法によるコロイダルシリカの製造は、従来公知の手法を用いて行うことができ、具体的には、加水分解可能なケイ素化合物(たとえば、アルコキシシランまたはその誘導体)を原料とし、加水分解・縮合反応を行うことにより、コロイダルシリカを得ることができる。 Methods for producing colloidal silica include the sodium silicate method and the sol-gel method, and colloidal silica produced by either method is suitable for use as the abrasive grains of the present invention. However, from the viewpoint of reducing metal impurities, colloidal silica produced by the sol-gel method is preferred. Colloidal silica produced by the sol-gel method is preferred because it contains less metal impurities that are diffusible in semiconductors and less corrosive ions such as chloride ions. Colloidal silica can be produced by the sol-gel method using a conventionally known method, and specifically, colloidal silica can be obtained by hydrolysis and condensation reaction using a hydrolyzable silicon compound (e.g., alkoxysilane or its derivative) as a raw material.
ここでカチオン変性とは、シリカ(好ましくはコロイダルシリカ)の表面にカチオン性基(例えば、アミノ基または第4級アンモニウム基)が結合した状態を意味する。そして、本発明の好ましい実施形態によれば、カチオン変性シリカ粒子は、アミノ基変性シリカ粒子であり、より好ましくはアミノ基変性コロイダルシリカ粒子である。かかる実施形態によれば、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより向上させることができる。また、かかる実施形態によれば、ポリシリコンを含む研磨対象物の研磨速度を高めることができる。 Here, cationically modified means a state in which a cationic group (e.g., an amino group or a quaternary ammonium group) is bonded to the surface of silica (preferably colloidal silica). According to a preferred embodiment of the present invention, the cationically modified silica particles are amino group-modified silica particles, and more preferably amino group-modified colloidal silica particles. According to such an embodiment, the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride can be further improved. Also, according to such an embodiment, the polishing rate of an object to be polished containing polysilicon can be increased.
シリカ(コロイダルシリカ)をカチオン変性するには、シリカ(コロイダルシリカ)に対して、カチオン性基(例えば、アミノ基または第4級アンモニウム基)を有するシランカップリング剤を加えて、所定の温度で所定時間反応させればよい。本発明の好ましい実施形態において、砥粒は、アミノ基を有するシランカップリング剤または第4級アンモニウム基を有するシランカップリング剤をシリカ(より好ましくはコロイダルシリカ)の表面に固定化させてなる。 To cationic modify silica (colloidal silica), a silane coupling agent having a cationic group (e.g., an amino group or a quaternary ammonium group) is added to the silica (colloidal silica) and reacted at a predetermined temperature for a predetermined time. In a preferred embodiment of the present invention, the abrasive grains are formed by immobilizing a silane coupling agent having an amino group or a silane coupling agent having a quaternary ammonium group on the surface of silica (more preferably colloidal silica).
この際、用いられるシランカップリング剤としては、例えば、特開2005-162533号公報に記載されているものが挙げられる。具体的には、N-(β-アミノエチル)-γ-アミノプロピルメチルジメトキシシラン、N-(β-アミノエチル)-γ-アミノプロピルトリメトキシシラン、N-(β-アミノエチル)-γ-アミノプロピルトリエトキシシラン、γ-アミノプロピルトリエトキシシラン((3-アミノプロピル)トリエトキシシラン)、γ-アミノプロピルトリメトキシシラン、γ-トリエトキシシリル-N-(α,γ-ジメチル-ブチリデン)プロピルアミン、N-フェニル-γ-アミノプロピルトリメトキシシラン、N-(ビニルベンジル)-β-アミノエチル-γ-アミノプロピルトリエトキシシランの塩酸塩、オクタデシルジメチル-(γ-トリメトキシシリルプロピル)-アンモニウムクロライド、N-トリメトキシシリルプロピル-N,N,N-トリメチルアンモニウムクロライド等のシランカップリング剤が挙げられる。なかでも、コロイダルシリカとの反応性が良好であることから、N-(β-アミノエチル)-γ-アミノプロピルトリメトキシシラン、N-(β-アミノエチル)-γ-アミノプロピルトリエトキシシラン、γ-アミノプロピルトリエトキシシラン、γ-アミノプロピルトリメトキシシランが好ましく用いられる。なお、本発明において、シランカップリング剤は、1種のみが単独で用いられてもよいし、2種以上を組み合わせて用いてもよい。 In this case, examples of the silane coupling agent used include those described in JP-A-2005-162533. Specific examples include silane coupling agents such as N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane ((3-aminopropyl)triethoxysilane), γ-aminopropyltrimethoxysilane, γ-triethoxysilyl-N-(α,γ-dimethyl-butylidene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, N-(vinylbenzyl)-β-aminoethyl-γ-aminopropyltriethoxysilane hydrochloride, octadecyldimethyl-(γ-trimethoxysilylpropyl)-ammonium chloride, and N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride. Among these, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, and γ-aminopropyltrimethoxysilane are preferably used because of their good reactivity with colloidal silica. In the present invention, the silane coupling agent may be used alone or in combination of two or more kinds.
なお、シランカップリング剤は、そのまま、または親水性有機溶媒もしくは純水で希釈して、シリカ(コロイダルシリカ)に加えることができる。親水性有機溶媒または純水で希釈することによって、凝集物の生成を抑制することができる。シランカップリング剤を親水性有機溶媒または純水で希釈する場合、シランカップリング剤が親水性有機溶媒または純水 1L中、0.01~1g、好ましくは0.1~0.7g程度の濃度になるように希釈すればよい。親水性有機溶媒としては、特に限定されないが、メタノール、エタノール、イソプロパノール、ブタノール等の低級アルコールなどを例示することができる。 The silane coupling agent can be added to the silica (colloidal silica) as is or after diluting with a hydrophilic organic solvent or pure water. By diluting with a hydrophilic organic solvent or pure water, the formation of aggregates can be suppressed. When diluting the silane coupling agent with a hydrophilic organic solvent or pure water, the silane coupling agent should be diluted to a concentration of about 0.01 to 1 g, preferably 0.1 to 0.7 g, per 1 L of hydrophilic organic solvent or pure water. The hydrophilic organic solvent is not particularly limited, but examples include lower alcohols such as methanol, ethanol, isopropanol, and butanol.
また、シリカ原料のpHとシランカップリング剤の添加量とを調節することにより、シリカ(コロイダルシリカ)の表面に導入されるカチオン性基の量を調節できると考えられる。シランカップリング剤の使用量は特に限定されないが、シリカ(コロイダルシリカ)に対して、好ましくは0.01質量%以上3.0質量%以下、より好ましくは0.05質量%以上1.0質量%以下程度である。 It is also believed that the amount of cationic groups introduced onto the surface of the silica (colloidal silica) can be adjusted by adjusting the pH of the silica raw material and the amount of silane coupling agent added. The amount of silane coupling agent used is not particularly limited, but is preferably 0.01% by mass or more and 3.0% by mass or less, more preferably 0.05% by mass or more and 1.0% by mass or less, relative to the silica (colloidal silica).
シランカップリング剤でシリカ(コロイダルシリカ)をカチオン変性する際の処理温度は特に限定されず、室温(例えば、25℃)から、シリカ(コロイダルシリカ)を分散する分散媒の沸点程度の温度であればよく、具体的には0℃以上100℃以下、好ましくは室温(例えば、25℃)以上90℃以下程度とされる。 The treatment temperature when cationically modifying silica (colloidal silica) with a silane coupling agent is not particularly limited, and may be from room temperature (e.g., 25°C) to a temperature about the boiling point of the dispersion medium in which the silica (colloidal silica) is dispersed, specifically from 0°C to 100°C, and preferably from room temperature (e.g., 25°C) to 90°C.
砥粒の形状は、特に制限されず、球形状であってもよいし、非球形状であってもよい。非球形状の具体例としては、三角柱や四角柱などの多角柱状、円柱状、円柱の中央部が端部よりも膨らんだ俵状、円盤の中央部が貫通しているドーナツ状、板状、中央部にくびれを有するいわゆる繭型形状、複数の粒子が一体化しているいわゆる会合型球形状、表面に複数の突起を有するいわゆる金平糖形状、ラグビーボール形状等、種々の形状が挙げられ、特に制限されない。 The shape of the abrasive grains is not particularly limited and may be spherical or non-spherical. Specific examples of non-spherical shapes include polygonal prisms such as triangular prisms and square prisms, cylinders, bale shapes in which the center of a cylinder is more bulging than the ends, donut shapes with a disk penetrating the center, plate shapes, so-called cocoon shapes with a constriction in the center, so-called associative spheres in which multiple particles are integrated, so-called confetti shapes with multiple protrusions on the surface, and rugby ball shapes, and various other shapes are not particularly limited.
砥粒の大きさは特に制限されない。例えば、砥粒の平均一次粒子径は、10nm以上であることが好ましく、15nm以上であることがより好ましく、20nm以上であることがさらに好ましい。砥粒の平均一次粒子径が大きくなるにつれて、研磨用組成物による研磨対象物の研磨速度が向上する。また、砥粒の平均一次粒子径は、300nm以下であることが好ましく、100nm以下であることがより好ましく、50nm以下であることがさらに好ましく、30nm以下が最も好ましい。砥粒の平均一次粒子径が小さくなるにつれて、研磨用組成物を用いた研磨により欠陥が少ない表面を得ることが容易になる。すなわち、砥粒の平均一次粒子径は、10nm以上300nm以下であることが好ましく、15nm以上100nm以下であることがより好ましく、20nm以上50nm以下であることがさらに好ましく、20nm以上30nm以下であることが最も好ましい。なお、砥粒の平均一次粒子径は、例えば、BET法から算出した砥粒の比表面積(SA)を基に、砥粒の形状が真球であると仮定して算出することができる。本明細書では、砥粒の平均一次粒子径は、実施例に記載の方法により測定された値を採用する。 The size of the abrasive grains is not particularly limited. For example, the average primary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more. As the average primary particle diameter of the abrasive grains increases, the polishing speed of the object to be polished by the polishing composition increases. In addition, the average primary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 100 nm or less, even more preferably 50 nm or less, and most preferably 30 nm or less. As the average primary particle diameter of the abrasive grains decreases, it becomes easier to obtain a surface with fewer defects by polishing with the polishing composition. That is, the average primary particle diameter of the abrasive grains is preferably 10 nm or more and 300 nm or less, more preferably 15 nm or more and 100 nm or less, even more preferably 20 nm or more and 50 nm or less, and most preferably 20 nm or more and 30 nm or less. The average primary particle diameter of the abrasive grains can be calculated, for example, based on the specific surface area (SA) of the abrasive grains calculated by the BET method, assuming that the shape of the abrasive grains is a true sphere. In this specification, the average primary particle size of the abrasive grains is the value measured by the method described in the Examples.
また、砥粒の平均二次粒子径は、20nm以上であることが好ましく、30nm以上であることがより好ましく、35nm以上であることがさらに好ましい。砥粒の平均二次粒子径が大きくなるにつれて、研磨中の抵抗が小さくなり、安定的な研磨が可能になる。また、砥粒の平均二次粒子径は、400nm以下であることが好ましく、250nm以下であることがより好ましく、100nm以下であることがさらに好ましく、70nm以下であることが最も好ましい。砥粒の平均二次粒子径が小さくなるにつれて、砥粒の単位質量当たりの表面積が大きくなり、研磨対象物との接触頻度が向上し、研磨速度がより向上する。すなわち、砥粒の平均二次粒子径は、20nm以上400nm以下であることが好ましく、30nm以上250nm以下であることがより好ましく、35nm以上100nm以下であることがさらに好ましく、35nm以上70nm以下であることが特に好ましい。なお、砥粒の平均二次粒子径は、例えばレーザー回折散乱法に代表される動的光散乱法により測定することができる。本明細書では、砥粒の平均二次粒子径は、実施例に記載の方法により測定された値を採用する。 The average secondary particle diameter of the abrasive grains is preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 35 nm or more. As the average secondary particle diameter of the abrasive grains increases, the resistance during polishing decreases, enabling stable polishing. The average secondary particle diameter of the abrasive grains is preferably 400 nm or less, more preferably 250 nm or less, even more preferably 100 nm or less, and most preferably 70 nm or less. As the average secondary particle diameter of the abrasive grains decreases, the surface area per unit mass of the abrasive grains increases, the frequency of contact with the object to be polished increases, and the polishing speed increases. That is, the average secondary particle diameter of the abrasive grains is preferably 20 nm or more and 400 nm or less, more preferably 30 nm or more and 250 nm or less, even more preferably 35 nm or more and 100 nm or less, and particularly preferably 35 nm or more and 70 nm or less. The average secondary particle diameter of the abrasive grains can be measured, for example, by a dynamic light scattering method represented by a laser diffraction scattering method. In this specification, the average secondary particle size of the abrasive grains is the value measured by the method described in the Examples.
砥粒の平均会合度は、5.0以下であることが好ましく、4.0以下であることがより好ましく、3.0以下であることがさらに好ましく、2.5以下がさらにより好ましく、2.3以下が最も好ましい。砥粒の平均会合度が小さくなるにつれて、欠陥をより低減することができる。砥粒の平均会合度はまた、1.0以上であることが好ましく、1.5以上であることがより好ましく、2.0以上であることがさらに好ましい。この平均会合度とは、砥粒の平均二次粒子径の値を平均一次粒子径の値で除することにより得られる。砥粒の平均会合度が大きくなるにつれて、研磨用組成物による研磨対象物の研磨速度が向上する有利な効果がある。 The average degree of association of the abrasive grains is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.0 or less, even more preferably 2.5 or less, and most preferably 2.3 or less. As the average degree of association of the abrasive grains decreases, defects can be further reduced. The average degree of association of the abrasive grains is also preferably 1.0 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. This average degree of association is obtained by dividing the average secondary particle diameter of the abrasive grains by the average primary particle diameter. As the average degree of association of the abrasive grains increases, there is an advantageous effect of improving the polishing speed of the object to be polished by the polishing composition.
研磨用組成物中の砥粒のアスペクト比の上限は、特に制限されないが、2.0未満であることが好ましく、1.8以下であることがより好ましく、1.5以下であることがさらに好ましい。このような範囲であれば、研磨対象物表面の欠陥をより低減することができる。なお、アスペクト比は、走査型電子顕微鏡により砥粒粒子の画像に外接する最小の長方形をとり、その長方形の長辺の長さを同じ長方形の短辺の長さで除することにより得られる値の平均であり、一般的な画像解析ソフトウエアを用いて求めることができる。研磨用組成物中の砥粒のアスペクト比の下限は、特に制限されないが、1.0以上であることが好ましい。 The upper limit of the aspect ratio of the abrasive grains in the polishing composition is not particularly limited, but is preferably less than 2.0, more preferably 1.8 or less, and even more preferably 1.5 or less. Within such a range, defects on the surface of the object to be polished can be further reduced. The aspect ratio is the average of the values obtained by taking the smallest rectangle that circumscribes the image of the abrasive grains taken with a scanning electron microscope and dividing the length of the long side of the rectangle by the length of the short side of the same rectangle, and can be determined using general image analysis software. The lower limit of the aspect ratio of the abrasive grains in the polishing composition is not particularly limited, but is preferably 1.0 or more.
砥粒のレーザー回折散乱法により求められる粒度分布において、微粒子側から積算粒子重量が全粒子重量の90%に達するときの粒子の直径(D90)と全粒子の全粒子重量の50%に達するときの粒子の直径(D50)との比であるD90/D50の下限は、特に制限されないが、1.1以上であることが好ましく、1.2以上であることがより好ましく、1.3以上であることがさらに好ましい。また、研磨用組成物中の砥粒における、レーザー回折散乱法により求められる粒度分布において、微粒子側から積算粒子重量が全粒子重量の90%に達するときの粒子の直径(D90)と全粒子の全粒子重量の50%に達するときの粒子の直径(D50)との比D90/D50の上限は特に制限されないが、2.0以下であることが好ましく、1.7以下であることがより好ましく、1.5であることがさらに好ましい。このような範囲であれば、研磨対象物表面の欠陥をより低減することができる。 In the particle size distribution of abrasive grains obtained by the laser diffraction scattering method, the lower limit of D90/D50, which is the ratio of the particle diameter (D90) when the cumulative particle weight from the fine particle side reaches 90% of the total particle weight and the particle diameter (D50) when the cumulative particle weight reaches 50% of the total particle weight of all particles, is not particularly limited, but is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more. In addition, in the particle size distribution of abrasive grains in a polishing composition obtained by the laser diffraction scattering method, the upper limit of the ratio D90/D50, which is the particle diameter (D90) when the cumulative particle weight from the fine particle side reaches 90% of the total particle weight and the particle diameter (D50) when the cumulative particle weight reaches 50% of the total particle weight of all particles, is not particularly limited, but is preferably 2.0 or less, more preferably 1.7 or less, and even more preferably 1.5. Within such a range, defects on the surface of the object to be polished can be further reduced.
砥粒の大きさ(平均一次粒子径、平均二次粒子径、アスペクト比、D90/D50等)は、砥粒の製造方法の選択等により適切に制御することができる。 The size of the abrasive grains (average primary particle size, average secondary particle size, aspect ratio, D90/D50, etc.) can be appropriately controlled by selecting the manufacturing method of the abrasive grains, etc.
砥粒の含有量(濃度)は特に制限されないが、研磨用組成物の総質量に対して、0.1質量%以上であることが好ましく、0.2質量%以上であることがより好ましく、0.5質量%以上であることがさらに好ましく、0.5質量%超であることが特に好ましい。また、砥粒の含有量の上限は、研磨用組成物の総質量に対して、10質量%以下であることが好ましく、5質量%以下であることがより好ましく、3質量%未満であることがさらに好ましく、1質量%未満であることが特に好ましい。すなわち、砥粒の含有量は、研磨用組成物の総質量に対して、0.1質量%以上10質量%以下が好ましく、0.2質量%以上5質量%以下がより好ましく、0.5質量%以上3質量%未満がさらに好ましく、0.5質量%超1質量%未満が特に好ましい。このような範囲であれば、コストを抑えながら、窒化ケイ素の研磨速度を低く抑えることができる。ゆえに、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより向上させることができる。また、このような範囲であれば、ポリシリコンの研磨速度と窒化ケイ素の研磨速度とのバランスをより向上させることができる。加えて、ポリシリコンの研磨速度と酸化ケイ素の研磨速度とをより同等の速度にする(酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより1に近づける)ことができる。なお、研磨用組成物が2種以上の砥粒を含む場合には、砥粒の含有量は、これらの合計量を意図する。 The content (concentration) of the abrasive grains is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably more than 0.5% by mass, relative to the total mass of the polishing composition. The upper limit of the content of the abrasive grains is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably less than 3% by mass, and particularly preferably less than 1% by mass, relative to the total mass of the polishing composition. That is, the content of the abrasive grains is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 5% by mass or less, even more preferably 0.5% by mass or more and less than 3% by mass, and particularly preferably more than 0.5% by mass and less than 1% by mass, relative to the total mass of the polishing composition. Within such a range, the polishing rate of silicon nitride can be kept low while keeping costs down. Therefore, the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride can be further improved. In addition, within this range, the balance between the polishing rate of polysilicon and the polishing rate of silicon nitride can be improved. In addition, the polishing rate of polysilicon and the polishing rate of silicon oxide can be made more equivalent (the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon oxide can be made closer to 1). When the polishing composition contains two or more types of abrasive grains, the content of the abrasive grains refers to the total amount of these.
[式(1)の化合物]
本発明の研磨用組成物は、式(1):N(R1)(R2)-C(=O)-N(R3)(R4)(式中、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す)で示される構造を有する化合物(式(1)の化合物)を含む。式(1)の化合物に存在する=N-C(=O)-N=部分の窒素原子に存在する非共有電子対が高い電子供与性(求核性)を有する。加えて、研磨用組成物に含まれる式(1)の化合物は、=N-C(=O)-N=部分の両末端に少なくとも1個のアルキル基が存在するため、電子の動きがよりスムーズであり、電子供与性(求核性)がより高まる。この窒素原子の求核作用により、ポリシリコンが有するケイ素-ケイ素結合は弱くなり、ポリシリコンの研磨速度が向上すると考えられる。また、研磨対象物がポリシリコンとともに窒化ケイ素を含む場合、窒化ケイ素に対して上記作用は働き難いため、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)が向上すると考えられる。
[Compound of formula (1)]
The polishing composition of the present invention contains a compound (compound of formula (1)) having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms). The unshared electron pair present in the nitrogen atom of the =N-C(═O)-N= portion present in the compound of formula (1) has high electron donating (nucleophilic) properties. In addition, the compound of formula (1) contained in the polishing composition has at least one alkyl group at both ends of the =N-C(═O)-N= portion, so that the movement of electrons is smoother and the electron donating (nucleophilic) properties are further enhanced. It is believed that the nucleophilic action of this nitrogen atom weakens the silicon-silicon bond of the polysilicon, thereby improving the polishing rate of the polysilicon. Furthermore, when the object to be polished contains silicon nitride as well as polysilicon, the above-mentioned effect is less likely to act on silicon nitride, and it is therefore believed that the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (selectivity) will improve.
式(1):N(R1)(R2)-C(=O)-N(R3)(R4)において、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表す。ここで、R1~R4は、同一であっても、または異なるものであってもよい。上記アルキル基としては、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、sec-ブチル基、tert-ブチル基からなる群より選択される直鎖または分岐鎖のアルキル基がある。これらのうち、炭素数1~3のアルキル基がより好ましく、メチル基、エチル基がさらに好ましく、メチル基が特に好ましい。 In the formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ), R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Here, R 1 to R 4 may be the same or different. The alkyl group may be a straight-chain or branched-chain alkyl group selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Among these, an alkyl group having 1 to 3 carbon atoms is more preferred, a methyl group or an ethyl group is even more preferred, and a methyl group is particularly preferred.
また、上記式(1)において、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す。R1~R4の少なくとも1つが上記したようなアルキル基であると、電子がさらによりスムーズに動き、電子供与性(求核性)をさらに高めることができる。また、R1~R4に占めるアルキル基の数は1~4であるが、アルキル基数に比例して、電子の動きがよりスムーズになり、電子供与性(求核性)がさらに高まる(ゆえに、窒化ケイ素に対するポリシリコンの選択比、ポリシリコンの研磨速度等がさらに向上できる)。このため、R1~R4に占めるアルキル基の数は、好ましくは2~4であり、より好ましくは3または4であり、特に好ましくは4である。すなわち、本発明の好ましい形態では、式(1)において、R1~R4の少なくとも1つは、炭素数1~4のアルキル基を表す。本発明のより好ましい形態では、式(1)において、R1~R4の少なくとも2つは、炭素数1~3のアルキル基を表す。本発明のさらに好ましい形態では、式(1)において、R1~R4の3つまたは4つが、それぞれ独立して、メチル基またはエチル基を表す。本発明の特に好ましい形態では、式(1)において、R1~R4すべてがメチル基を表す。 In addition, in the above formula (1), at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms. When at least one of R 1 to R 4 is an alkyl group as described above, electrons move more smoothly, and electron donating property (nucleophilicity) can be further increased. In addition, the number of alkyl groups in R 1 to R 4 is 1 to 4, and the movement of electrons becomes smoother in proportion to the number of alkyl groups, and the electron donating property (nucleophilicity) is further increased (therefore, the selectivity of polysilicon to silicon nitride, the polishing speed of polysilicon, etc. can be further improved). For this reason, the number of alkyl groups in R 1 to R 4 is preferably 2 to 4, more preferably 3 or 4, and particularly preferably 4. That is, in a preferred embodiment of the present invention, in formula (1), at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms. In a more preferred embodiment of the present invention, in formula (1), at least two of R 1 to R 4 represent alkyl groups having 1 to 3 carbon atoms. In a further preferred embodiment of the present invention, three or four of R 1 to R 4 in formula (1) each independently represent a methyl group or an ethyl group. In a particularly preferred embodiment of the present invention, all of R 1 to R 4 in formula (1) represent a methyl group.
式(1)の化合物の具体的な例としては、1-メチル尿素(式(1)中のR1=メチル基、R2,R3,R4=H)、1-エチル尿素(式(1)中のR1=エチル基、R2,R3,R4=H)、1-プロピル尿素(式(1)中のR1=プロピル基、R2,R3,R4=H)、1,1-ジメチル尿素(式(1)中のR1,R2=メチル基、R3,R4=H)、1,3-ジメチル尿素(式(1)中のR1,R2=H,メチル基、R3,R4=H,メチル基)、1,1-ジエチル尿素(式(1)中のR1,R2=エチル基、R3,R4=H)、1,3-ジエチル尿素(式(1)中のR1,R2=H,エチル基、R3,R4=H,エチル基)、1-メチル-1-エチル尿素(式(1)中のR1,R2=メチル基,エチル基、R3,R4=H)、1-メチル-3-エチル尿素(式(1)中のR1,R2=H,メチル基、R3,R4=H,エチル基)、トリメチル尿素(式(1)中のR1,R2,R3=メチル基、R4=H)、トリエチル尿素(式(1)中のR1,R2,R3=エチル基、R4=H)、トリプロピル尿素(式(1)中のR1,R2,R3=プロピル基、R4=H)、1,1-ジメチル-3-エチル尿素(式(1)中のR1,R2=メチル基、R3=エチル基、R4=H)、1-メチル-1-エチル-3-エチル尿素(式(1)中のR1,R2=メチル基,エチル基、R3=エチル基、R4=H)、テトラメチル尿素(式(1)中のR1,R2,R3,R4=メチル基)、テトラエチル尿素(式(1)中のR1,R2,R3,R4=エチル基)、テトラプロピル尿素(式(1)中のR1,R2,R3,R4=プロピル基)等が挙げられる。 Specific examples of the compound of formula (1) include 1-methylurea (R 1 in formula (1) = methyl group, R 2 , R 3 , R 4 = H), 1-ethylurea (R 1 in formula (1) = ethyl group, R 2 , R 3 , R 4 = H), 1-propylurea (R 1 in formula (1) = propyl group, R 2 , R 3 , R 4 = H), 1,1-dimethylurea (R 1 and R 2 in formula (1) = methyl group, R 3 and R 4 = H), 1,3-dimethylurea (R 1 and R 2 in formula (1) = H, methyl group, R 3 and R 4 = H, methyl group), 1,1-diethylurea (R 1 and R 2 in formula (1) = ethyl group, R 3 and R 4 = H, methyl group), =H), 1,3-diethylurea (R 1 and R 2 in formula (1) =H, ethyl group, R 3 and R 4 =H, ethyl group), 1-methyl-1-ethylurea (R 1 and R 2 in formula (1) =methyl group, ethyl group, R 3 and R 4 =H), 1-methyl-3-ethylurea (R 1 and R 2 in formula (1) =H, methyl group, R 3 and R 4 =H, ethyl group), trimethylurea (R 1 , R 2 and R 3 in formula (1) =methyl group, R 4 =H), triethylurea (R 1 , R 2 and R 3 in formula (1) =ethyl group, R 4 =H), tripropylurea (R 1 , R 2 and R 3 in formula (1) =propyl group, R 4 =H), =H), 1,1-dimethyl-3-ethylurea (in formula (1) R 1 and R 2 = methyl group, R 3 = ethyl group, and R 4 = H), 1-methyl-1-ethyl-3-ethylurea (in formula (1) R 1 and R 2 = methyl group and ethyl group, R 3 = ethyl group, and R 4 = H), tetramethylurea (in formula (1) R 1 , R 2 , R 3 , and R 4 = methyl group), tetraethylurea (in formula (1) R 1 , R 2 , R 3 , and R 4 = ethyl group), and tetrapropylurea (in formula (1) R 1 , R 2 , R 3 , and R 4 = propyl group).
上記式(1)の化合物は、1種単独でも、または2種以上組み合わせて用いてもよい。 The compound of formula (1) above may be used alone or in combination of two or more.
式(1)の化合物のより具体的な例としては、1-メチル尿素、1-エチル尿素、1,3-ジメチル尿素、1,3-ジエチル尿素、トリメチル尿素、トリエチル尿素、トリプロピル尿素、テトラメチル尿素、テトラエチル尿素、テトラプロピル尿素等が挙げられる。これらの式(1)の化合物の中でも、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)のさらなる向上効果、入手容易性等の観点から、1,3-ジメチル尿素、1,3-ジエチル尿素、トリメチル尿素、トリエチル尿素、テトラメチル尿素、テトラエチル尿素が好ましく、トリメチル尿素、トリエチル尿素、テトラメチル尿素、テトラエチル尿素がより好ましく、テトラメチル尿素、テトラエチル尿素がさらに好ましく、テトラメチル尿素が特に好ましい。 More specific examples of the compound of formula (1) include 1-methylurea, 1-ethylurea, 1,3-dimethylurea, 1,3-diethylurea, trimethylurea, triethylurea, tripropylurea, tetramethylurea, tetraethylurea, tetrapropylurea, etc. Among these compounds of formula (1), from the viewpoint of the effect of further improving the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon nitride, ease of availability, etc., 1,3-dimethylurea, 1,3-diethylurea, trimethylurea, triethylurea, tetramethylurea, and tetraethylurea are preferred, trimethylurea, triethylurea, tetramethylurea, and tetraethylurea are more preferred, tetramethylurea and tetraethylurea are even more preferred, and tetramethylurea is particularly preferred.
使用する式(1)の化合物は、1種単独でも、または2種以上組み合わせても用いることができる。また、式(1)の化合物は市販品でもよいし合成品でもよい。市販品としては、東京化成工業株式会社、富士フイルム和光純薬株式会社、シグマアルドリッチ社等から入手できる。 The compound of formula (1) used may be used alone or in combination of two or more. The compound of formula (1) may be a commercially available product or a synthetic product. Commercially available products are available from Tokyo Chemical Industry Co., Ltd., Fujifilm Wako Pure Chemical Industries, Ltd., Sigma-Aldrich Corporation, etc.
式(1)の化合物の含有量(濃度)は特に制限されないが、研磨用組成物の総質量に対して、0.0001質量%以上であることが好ましく、0.0005質量%以上であることがより好ましく、0.001質量%以上であることがさらに好ましく、0.01質量%以上であることが特に好ましい。また、式(1)の化合物の含有量の上限は、研磨用組成物の総質量に対して、1質量%未満であることが好ましく、0.5質量%以下であることがより好ましく、0.1質量%以下であることがさらに好ましく、0.1質量%未満であることが特に好ましい。すなわち、式(1)の化合物の含有量は、研磨用組成物の総質量に対して、0.0001質量%以上1質量%未満が好ましく、0.0005質量%以上0.5量%以下がより好ましく、0.001質量%以上0.1質量%以下がさらに好ましく、0.01質量%以上0.1質量%未満が特に好ましい。このような含有量の範囲であれば、コストを抑えながら、窒化ケイ素の研磨速度を低く抑えることができる。ゆえに、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより向上させることができる。また、このような含有量の範囲であれば、ポリシリコンの研磨速度と窒化ケイ素の研磨速度とのバランスをより向上させることができる。加えて、ポリシリコンの研磨速度と酸化ケイ素の研磨速度とをより同等の速度にする(酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより1に近づける)ことができる。なお、研磨用組成物が2種以上の式(1)の化合物を含む場合には、式(1)の化合物の含有量は、これらの合計量を意図する。 The content (concentration) of the compound of formula (1) is not particularly limited, but is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, and particularly preferably 0.01% by mass or more, relative to the total mass of the polishing composition. The upper limit of the content of the compound of formula (1) is preferably less than 1% by mass, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably less than 0.1% by mass, relative to the total mass of the polishing composition. That is, the content of the compound of formula (1) is preferably 0.0001% by mass or more and less than 1% by mass, more preferably 0.0005% by mass or more and 0.5% by mass or less, even more preferably 0.001% by mass or more and 0.1% by mass or less, and particularly preferably 0.01% by mass or more and less than 0.1% by mass. Within such a content range, the polishing rate of silicon nitride can be kept low while keeping costs down. Therefore, the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride can be further improved. Furthermore, within this range of content, the balance between the polishing rate of polysilicon and the polishing rate of silicon nitride can be further improved. In addition, the polishing rate of polysilicon and the polishing rate of silicon oxide can be made more equivalent (the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon oxide can be made closer to 1). Note that, when the polishing composition contains two or more compounds of formula (1), the content of the compound of formula (1) refers to the total amount of these.
また、式(1)の化合物と砥粒との混合割合は特に制限されないが、式(1)の化合物が、砥粒 100質量部に対して、5質量部を超える割合で含まれることが好ましく、10質量部以上の割合で含まれることがより好ましく、10質量部を超える割合で含まれることがさらに好ましく、11質量部以上の割合で含まれることが特に好ましい。また、式(1)の化合物は、砥粒 100質量部に対して、50質量部以下の割合で含まれることが好ましく、30質量部未満の割合で含まれることがより好ましく、25質量部以下の割合で含まれることがさらに好ましく、20質量部未満の割合で含まれることが特に好ましく、15質量部以下の割合で含まれることが最も好ましい。すなわち、式(1)の化合物が、砥粒 100質量部に対して、5質量部を超え50質量部以下の割合で含まれることが好ましく、5質量部を超え30質量部未満の割合で含まれることがより好ましく、10質量部以上25質量部以下の割合で含まれることがさらに好ましく、10質量部を超え20質量部未満の割合で含まれることが特に好ましく、11質量部以上15質量部以下の割合で含まれることが最も好ましい。このような混合比であれば、式(1)の化合物が砥粒により有効に作用し、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより向上させることができる。また、このような混合比であれば、ポリシリコンの研磨速度と窒化ケイ素の研磨速度とのバランスをより向上させることができる。加えて、ポリシリコンの研磨速度と酸化ケイ素の研磨速度とをより同等の速度にする(酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)をより1に近づける)ことができる。なお、研磨用組成物が2種以上の式(1)の化合物を含む場合には、式(1)の化合物の含有量は、これらの合計量を意図する。同様にして、研磨用組成物が2種以上の砥粒を含む場合には、砥粒の含有量は、これらの合計量を意図する。 In addition, the mixing ratio of the compound of formula (1) and the abrasive grains is not particularly limited, but the compound of formula (1) is preferably contained in a ratio of more than 5 parts by mass, more preferably 10 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 11 parts by mass or more, relative to 100 parts by mass of the abrasive grains. In addition, the compound of formula (1) is preferably contained in a ratio of 50 parts by mass or less, more preferably less than 30 parts by mass, even more preferably 25 parts by mass or less, particularly preferably less than 20 parts by mass, and most preferably 15 parts by mass or less, relative to 100 parts by mass of the abrasive grains. That is, the compound of formula (1) is preferably contained in a ratio of more than 5 parts by mass to 50 parts by mass or less, more preferably more than 5 parts by mass to less than 30 parts by mass, even more preferably 10 parts by mass to 25 parts by mass or less, particularly preferably more than 10 parts by mass to less than 20 parts by mass, and most preferably 11 parts by mass to 15 parts by mass or less. With such a mixing ratio, the compound of formula (1) acts more effectively on the abrasive grains, and the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon nitride can be further improved. Furthermore, with such a mixing ratio, the balance between the polishing speed of polysilicon and the polishing speed of silicon nitride can be further improved. In addition, the polishing speed of polysilicon and the polishing speed of silicon oxide can be made more equivalent (the ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon oxide can be made closer to 1). In addition, when the polishing composition contains two or more compounds of formula (1), the content of the compounds of formula (1) refers to the total amount of these. Similarly, when the polishing composition contains two or more types of abrasive grains, the content of the abrasive grains refers to the total amount of these.
[分散媒]
本発明の研磨用組成物は、各成分を分散するための分散媒を含むことが好ましい。分散媒としては、水;メタノール、エタノール、エチレングリコール等のアルコール類;アセトン等のケトン類等や、これらの混合物などが例示できる。これらのうち、分散媒としては水が好ましい。すなわち、本発明のより好ましい形態によると、分散媒は水を含む。本発明のさらに好ましい形態によると、分散媒は実質的に水からなる。なお、上記の「実質的に」とは、本発明の目的効果が達成され得る限りにおいて、水以外の分散媒が含まれ得ることを意図し、より具体的には、好ましくは90質量%以上100質量%以下の水と0質量%以上10質量%以下の水以外の分散媒とからなり、より好ましくは99質量%以上100質量%以下の水と0質量%以上1質量%以下の水以外の分散媒とからなる。上記したように、さらに好ましくは、分散媒は水のみからなる。
[Dispersion medium]
The polishing composition of the present invention preferably contains a dispersion medium for dispersing each component. Examples of the dispersion medium include water; alcohols such as methanol, ethanol, and ethylene glycol; ketones such as acetone, and mixtures thereof. Of these, water is preferred as the dispersion medium. That is, according to a more preferred embodiment of the present invention, the dispersion medium contains water. According to a further preferred embodiment of the present invention, the dispersion medium is substantially composed of water. Note that the above "substantially" means that a dispersion medium other than water may be included as long as the objective effect of the present invention can be achieved, and more specifically, the dispersion medium is preferably composed of 90% by mass or more and 100% by mass or less of water and 0% by mass or more and 10% by mass or less of a dispersion medium other than water, and more preferably composed of 99% by mass or more and 100% by mass or less of water and 0% by mass or more and 1% by mass or less of a dispersion medium other than water. As described above, more preferably, the dispersion medium is composed of only water.
研磨用組成物に含まれる成分の作用を阻害しないようにするという観点から、分散媒としては、不純物をできる限り含有しない水が好ましく、具体的には、イオン交換樹脂にて不純物イオンを除去した後、フィルタを通して異物を除去した純水や超純水、または蒸留水がより好ましい。 From the viewpoint of not inhibiting the action of the components contained in the polishing composition, the dispersion medium is preferably water that contains as few impurities as possible. Specifically, pure water or ultrapure water that has been filtered to remove foreign matter after removing impurity ions with an ion exchange resin, or distilled water is more preferable.
[pH]
本発明の研磨用組成物のpHは、6.0未満である。pHが6.0以上であると、=N-C(=O)-N=部分の窒素原子に存在する非共有電子対が高い電子供与性(求核性)が過度に低下して、ポリシリコンや酸化ケイ素の研磨速度(ゆえに窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比))が過度に低下して、好ましくない。研磨用組成物のpHは、5.5以下が好ましく、5.5未満がより好ましく、5.0以下がさらに好ましく、5.0未満が特に好ましい。研磨用組成物のpHの下限は、特に制限されないが、砥粒のゼータ電位(ゆえに、砥粒と研磨対象物(特に酸化ケイ素)との引き合い)を適切に調節できるとの観点から、3.5以上が好ましく、3.5超がより好ましく、3.7以上がさらに好ましく、3.7超が特に好ましい。すなわち、研磨用組成物のpHは、3.5以上5.5以下が好ましく、3.5超5.5未満がより好ましく、3.7以上5.0以下がさらに好ましく、3.7超5.0未満が特に好ましい。
[pH]
The pH of the polishing composition of the present invention is less than 6.0. If the pH is 6.0 or more, the high electron donative property (nucleophilicity) of the unshared electron pair present in the nitrogen atom of the =N-C(=O)-N= portion is excessively decreased, and the polishing rate of polysilicon or silicon oxide (hence the ratio (selectivity) of the polishing rate of polysilicon to the polishing rate of silicon nitride) is excessively decreased, which is undesirable. The pH of the polishing composition is preferably 5.5 or less, more preferably less than 5.5, even more preferably 5.0 or less, and particularly preferably less than 5.0. The lower limit of the pH of the polishing composition is not particularly limited, but from the viewpoint of being able to appropriately adjust the zeta potential of the abrasive (hence the attraction between the abrasive and the object to be polished (particularly silicon oxide)), it is preferably 3.5 or more, more preferably more than 3.5, even more preferably 3.7 or more, and particularly preferably more than 3.7. That is, the pH of the polishing composition is preferably 3.5 or more and 5.5 or less, more preferably more than 3.5 and less than 5.5, even more preferably 3.7 or more and 5.0 or less, and particularly preferably more than 3.7 and less than 5.0.
研磨用組成物のpHは、pHメーター(株式会社堀場製作所製、型番:LAQUA)により測定することができる。 The pH of the polishing composition can be measured using a pH meter (manufactured by Horiba, Ltd., model number: LAQUA).
本発明の研磨用組成物においては、本発明の効果を阻害しない範囲内において、pH調整剤を添加してpHを調整してもよい。 In the polishing composition of the present invention, a pH adjuster may be added to adjust the pH within a range that does not impair the effects of the present invention.
pH調整剤は酸、塩基のいずれであってもよく、また、無機化合物および有機化合物のいずれであってもよい。pH調整剤は、単独でもまたは2種以上混合しても用いることができる。 The pH adjuster may be either an acid or a base, and may be either an inorganic compound or an organic compound. The pH adjuster may be used alone or in combination of two or more kinds.
pH調整剤として用いられる酸の具体例としては、例えば、硫酸、硝酸、ホウ酸、炭酸、次亜リン酸、亜リン酸、およびリン酸等の無機酸;ギ酸、酢酸、プロピオン酸、酪酸、吉草酸、2-メチル酪酸、n-ヘキサン酸、3,3-ジメチル酪酸、2-エチル酪酸、4-メチルペンタン酸、n-ヘプタン酸、2-メチルヘキサン酸、n-オクタン酸、2-エチルヘキサン酸、安息香酸、グリコール酸、サリチル酸、グリセリン酸、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、マレイン酸、フタル酸、リンゴ酸、酒石酸、クエン酸および乳酸などのカルボン酸、ならびにメタンスルホン酸、エタンスルホン酸およびイセチオン酸等の有機硫酸等の有機酸等が挙げられる。 Specific examples of acids used as pH adjusters include inorganic acids such as sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid; carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid; and organic acids such as organic sulfuric acids such as methanesulfonic acid, ethanesulfonic acid, and isethionic acid.
pH調整剤として用いられる塩基の具体例としては、例えば、第1族元素の水酸化物または塩、第2族元素の水酸化物または塩、水酸化第4級アンモニウムまたはその塩等が挙げられる。塩の具体例としては、炭酸塩、炭酸水素塩、硫酸塩、酢酸塩等が挙げられる。 Specific examples of bases used as pH adjusters include hydroxides or salts of Group 1 elements, hydroxides or salts of Group 2 elements, quaternary ammonium hydroxide or its salts, etc. Specific examples of salts include carbonates, hydrogen carbonates, sulfates, acetates, etc.
pH調整剤の添加量は、特に制限されず、研磨用組成物が所望のpHとなるように適宜調整すればよい。 The amount of pH adjuster added is not particularly limited, and may be adjusted appropriately so that the polishing composition has the desired pH.
[研磨用組成物の電気伝導度(EC)]
本発明の研磨用組成物の電気伝導度(EC)の下限は、好ましくは0.01mS/cm以上であり、より好ましくは0.1mS/cm以上である。また、本発明の研磨用組成物の電気伝導度(EC)の上限は、好ましくは10mS/cm以下であり、より好ましくは3mS/cm以下である。上記したような範囲であれば、砥粒同士の反発を適切に調整して、(特にポリシリコンに対する)十分な研磨速度および安定性を確保できる。研磨用組成物の電気伝導度は、式(1)の化合物の種類および量、研磨用組成物のpH、pH調整剤の種類および量等により調整することができる。なお、研磨用組成物の電気伝導度は、卓上型電気伝導度計(株式会社堀場製作所製、型番:DS-71)により測定される値である。
[Electrical Conductivity (EC) of Polishing Composition]
The lower limit of the electrical conductivity (EC) of the polishing composition of the present invention is preferably 0.01 mS/cm or more, more preferably 0.1 mS/cm or more. The upper limit of the electrical conductivity (EC) of the polishing composition of the present invention is preferably 10 mS/cm or less, more preferably 3 mS/cm or less. Within the above range, the repulsion between the abrasive grains can be appropriately adjusted to ensure sufficient polishing speed and stability (especially for polysilicon). The electrical conductivity of the polishing composition can be adjusted by the type and amount of the compound of formula (1), the pH of the polishing composition, the type and amount of the pH adjuster, etc. The electrical conductivity of the polishing composition is a value measured by a tabletop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71).
[その他の成分]
本発明の研磨用組成物は、本発明の効果が著しく妨げられない範囲で、錯化剤、防腐剤、防カビ剤等の、研磨用組成物に用いられ得る公知の添加剤を、必要に応じてさらに含有してもよい。
[Other ingredients]
The polishing composition of the present invention may further contain, as necessary, known additives that can be used in polishing compositions, such as complexing agents, preservatives, and anti-fungal agents, to the extent that the effects of the present invention are not significantly impeded.
本発明に係る研磨用組成物は、酸化剤を実質的に含有しないことが好ましい。研磨用組成物中に酸化剤が含まれていると、研磨対象物(例えばポリシリコン)の表面を酸化して酸化膜を生じさせ、研磨時間が長くなってしまう虞がある。ここでいう酸化剤の具体例としては、過酸化水素(H2O2)、過硫酸ナトリウム、過硫酸アンモニウム、ジクロロイソシアヌル酸ナトリウム等が挙げられる。なお、研磨用組成物が酸化剤を実質的に含有しないとは、少なくとも意図的には酸化剤を含有させないことをいう。したがって、原料や製法等に由来して微量の酸化剤が不可避的に含まれている研磨用組成物は、ここでいう酸化剤を実質的に含有しない研磨用組成物の概念に包含される。例えば、研磨用組成物中における酸化剤の濃度は、好ましくは0.001質量%以下、より好ましくは0.0001質量%以下、さらに好ましくは0.00001質量%以下(下限:0質量%)である。 The polishing composition according to the present invention preferably does not substantially contain an oxidizing agent. If an oxidizing agent is contained in the polishing composition, the surface of the object to be polished (e.g., polysilicon) is oxidized to generate an oxide film, which may lengthen the polishing time. Specific examples of the oxidizing agent include hydrogen peroxide (H 2 O 2 ), sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate. The polishing composition substantially does not contain an oxidizing agent means that the oxidizing agent is not intentionally contained at least. Therefore, a polishing composition that inevitably contains a small amount of oxidizing agent due to raw materials, manufacturing method, etc. is included in the concept of a polishing composition that does not substantially contain an oxidizing agent. For example, the concentration of the oxidizing agent in the polishing composition is preferably 0.001% by mass or less, more preferably 0.0001% by mass or less, and even more preferably 0.00001% by mass or less (lower limit: 0% by mass).
[研磨用組成物の製造方法]
本発明の研磨用組成物の製造方法は、特に制限されず、例えば、砥粒、式(1)の化合物、および必要に応じて他の添加剤を、分散媒(例えば、水)中で攪拌混合することにより得ることができる。各成分の詳細は上述した通りである。したがって、本発明は、砥粒、および式(1)の化合物を混合する工程を含む、研磨用組成物の製造方法を提供する。
[Method of manufacturing the polishing composition]
The method for producing the polishing composition of the present invention is not particularly limited, and can be obtained, for example, by stirring and mixing abrasive grains, the compound of formula (1), and other additives as necessary in a dispersion medium (for example, water). The details of each component are as described above. Therefore, the present invention provides a method for producing a polishing composition, comprising the step of mixing abrasive grains and the compound of formula (1).
各成分を混合する際の温度は特に制限されないが、10℃以上40℃以下が好ましく、溶解速度を上げるために加熱してもよい。また、混合時間も、均一混合できれば特に制限されない。 The temperature at which the components are mixed is not particularly limited, but is preferably 10°C or higher and 40°C or lower, and may be heated to increase the dissolution rate. In addition, there is no particular limit to the mixing time as long as the components can be mixed uniformly.
[研磨方法および半導体基板の製造方法]
上述のように、本発明の研磨用組成物は、ポリシリコンを含む研磨対象物の研磨に好適に用いられる。よって、本発明は、ポリシリコンを含む研磨対象物を、本発明の研磨用組成物で研磨する研磨方法を提供する。
[Polishing method and manufacturing method of semiconductor substrate]
As described above, the polishing composition of the present invention is suitable for use in polishing an object to be polished that contains polysilicon. Thus, the present invention provides a polishing method for polishing an object to be polished that contains polysilicon with the polishing composition of the present invention.
さらに、本発明は、ポリシリコンを含む半導体基板を前記研磨方法で研磨する工程を含む半導体基板の製造方法を提供する。 The present invention further provides a method for manufacturing a semiconductor substrate, comprising the step of polishing a semiconductor substrate containing polysilicon by the above-mentioned polishing method.
研磨装置としては、研磨対象物を有する基板等を保持するホルダーと回転数を変更可能なモータ等とが取り付けてあり、研磨パッド(研磨布)を貼り付け可能な研磨定盤を有する一般的な研磨装置を使用することができる。 As a polishing device, a general polishing device can be used that is equipped with a holder for holding a substrate or the like having an object to be polished, a motor that can change the rotation speed, and a polishing platen onto which a polishing pad (polishing cloth) can be attached.
研磨パッドとしては、一般的な不織布、ポリウレタン、および多孔質フッ素樹脂等を特に制限なく使用することができる。研磨パッドには、研磨液が溜まるような溝加工が施されていることが好ましい。 As the polishing pad, general nonwoven fabric, polyurethane, porous fluororesin, etc. can be used without any particular restrictions. It is preferable that the polishing pad has grooves to allow the polishing liquid to accumulate.
研磨条件については、例えば、研磨定盤の回転速度は、10rpm(0.17s-1)以上500rpm(8.3s-1)以下が好ましい。研磨対象物を有する基板にかける圧力(研磨圧力)は、0.5psi(3.4kPa)以上10psi(68.9kPa)以下が好ましい。研磨パッドに研磨用組成物を供給する方法も特に制限されず、例えば、ポンプ等で連続的に供給する方法が採用される。この供給量に制限はないが、研磨パッドの表面が常に本発明の研磨用組成物で覆われていることが好ましい。 Regarding the polishing conditions, for example, the rotation speed of the polishing platen is preferably 10 rpm (0.17 s -1 ) or more and 500 rpm (8.3 s -1 ) or less. The pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. There are no particular limitations on the method of supplying the polishing composition to the polishing pad, and for example, a method of continuously supplying the composition using a pump or the like is adopted. There is no limitation on the amount of supply, but it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.
研磨終了後、基板を流水中で洗浄し、スピンドライヤ等により基板上に付着した水滴を払い落として乾燥させることにより、金属を含む層を有する基板が得られる。 After polishing is complete, the substrate is washed with running water, and the water droplets adhering to the substrate are removed using a spin dryer or the like, followed by drying to obtain a substrate having a metal-containing layer.
本発明の研磨用組成物は一液型であってもよいし、二液型をはじめとする多液型であってもよい。また、本発明の研磨用組成物は、研磨用組成物の原液を水などの希釈液を使って、例えば10倍以上に希釈することによって調製されてもよい。 The polishing composition of the present invention may be a one-component type or a multi-component type, such as a two-component type. The polishing composition of the present invention may also be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more, with a diluent such as water.
(研磨速度、選択比)
本発明の研磨用組成物を用いてポリシリコン及び窒化ケイ素を含む研磨対象物を研磨すると、高い窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(高い窒化ケイ素に対するポリシリコンの選択比)を達成できる。具体的には、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(窒化ケイ素に対するポリシリコンの選択比)は、15以上であることが好ましく、20以上であることがより好ましく、25以上であることがさらに好ましく、30以上であることが特に好ましい。なお、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(選択比)は、高いほど好ましいため、上限は特に制限されないが、通常、50以下である。
(polishing speed, selectivity)
When the polishing composition of the present invention is used to polish an object containing polysilicon and silicon nitride, a high ratio of the polishing speed of polysilicon to the polishing speed of silicon nitride (high selectivity of polysilicon to silicon nitride) can be achieved.Specifically, the ratio of the polishing speed of polysilicon to the polishing speed of silicon nitride (selectivity of polysilicon to silicon nitride) is preferably 15 or more, more preferably 20 or more, even more preferably 25 or more, and particularly preferably 30 or more.The ratio (selectivity) of the polishing speed of polysilicon to the polishing speed of silicon nitride is preferably as high as possible, so the upper limit is not particularly limited, but is usually 50 or less.
また、本発明の研磨用組成物を用いてポリシリコン及び酸化ケイ素を含む研磨対象物を研磨すると、ポリシリコン及び酸化ケイ素を実質的に同等の研磨速度で研磨できる。具体的には、酸化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(酸化ケイ素に対するポリシリコンの選択比)は、0.70を超えて1.30未満であることが好ましく、0.80以上1.20以下であることがより好ましく、0.95を超えて1.10未満であることがさらに好ましく、0.98を超えて1.05未満であることが特に好ましい。 In addition, when an object to be polished containing polysilicon and silicon oxide is polished using the polishing composition of the present invention, the polysilicon and silicon oxide can be polished at substantially the same polishing rate. Specifically, the ratio of the polishing rate of polysilicon to the polishing rate of silicon oxide (selectivity ratio of polysilicon to silicon oxide) is preferably greater than 0.70 and less than 1.30, more preferably 0.80 or more and 1.20 or less, even more preferably greater than 0.95 and less than 1.10, and particularly preferably greater than 0.98 and less than 1.05.
本発明の研磨用組成物を用いてポリシリコンを含む研磨対象物を研磨すると、高いポリシリコンの研磨速度を達成できる。具体的には、ポリシリコンの研磨速度は、600Å/min以上であると好ましく、700Å/min以上であることがより好ましく、800Å/min以上であることがさらに好ましい。なお、ポリシリコンの研磨速度の上限は、特に制限されないが、例えば、2000Å/min以下である。 When a polishing object containing polysilicon is polished using the polishing composition of the present invention, a high polishing rate for polysilicon can be achieved. Specifically, the polishing rate for polysilicon is preferably 600 Å/min or more, more preferably 700 Å/min or more, and even more preferably 800 Å/min or more. The upper limit of the polishing rate for polysilicon is not particularly limited, but is, for example, 2000 Å/min or less.
また、本発明の研磨用組成物を用いて窒化ケイ素を含む研磨対象物を研磨すると、窒化ケイ素の研磨速度を抑制できる。具体的には、窒化ケイ素の研磨速度は、70Å/min以下であると好ましく、50Å/min以下であることがより好ましく、40Å/min以下であることがさらに好ましく、30Å/min以下であることがさらに好ましい。なお、窒化ケイ素の研磨速度の下限は、可能な限り低い(ゆえに0Å/min)ことが好ましいが、例えば、5Å/min以上であれば十分である。 In addition, when a polishing object containing silicon nitride is polished using the polishing composition of the present invention, the polishing rate of silicon nitride can be suppressed. Specifically, the polishing rate of silicon nitride is preferably 70 Å/min or less, more preferably 50 Å/min or less, even more preferably 40 Å/min or less, and even more preferably 30 Å/min or less. It is preferable that the lower limit of the polishing rate of silicon nitride is as low as possible (hence 0 Å/min), but for example, 5 Å/min or more is sufficient.
本明細書において、ポリシリコン、窒化ケイ素および酸化ケイ素の研磨速度は、実施例に記載の方法により算出される値を採用する。本明細書において、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(窒化ケイ素に対するポリシリコンの選択比)および酸化ケイ素の研磨速度に対するポリシリコンの研磨度の比(酸化ケイ素に対するポリシリコンの選択比)は、実施例に記載の方法により算出される値を採用する。 In this specification, the polishing rates of polysilicon, silicon nitride, and silicon oxide are calculated by the method described in the Examples. In this specification, the ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (selectivity ratio of polysilicon to silicon nitride) and the ratio of the polishing degree of polysilicon to the polishing rate of silicon oxide (selectivity ratio of polysilicon to silicon oxide) are calculated by the method described in the Examples.
本発明を、以下の実施例および比較例を用いてさらに詳細に説明する。ただし、本発明の技術的範囲が以下の実施例のみに制限されるわけではない。なお、特記しない限り、「%」および「部」は、それぞれ、「質量%」および「質量部」を意味する。 The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.
(研磨用組成物の電気伝導度の測定)
研磨用組成物の電気伝導度(EC)(mS/cm)は、卓上型電気伝導度計(株式会社堀場製作所製、型番:DS-71)により測定した。
(Measurement of Electrical Conductivity of Polishing Composition)
The electrical conductivity (EC) (mS/cm) of the polishing composition was measured with a tabletop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71).
(砥粒のゼータ電位の測定)
調製した研磨用組成物を大塚電子株式会社製ELS-Z2に供し、測定温度25℃でフローセルを用い、レーザードップラー法(電気泳動光散乱測定法)により測定を行った。得られたデータをSmoluchowskiの式で解析することにより、研磨用組成物中の砥粒のゼータ電位(ζ電位)(mV)を算出した。
(Measurement of Zeta Potential of Abrasive Grains)
The prepared polishing composition was subjected to measurement by a laser Doppler method (electrophoretic light scattering measurement method) using an ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., and a flow cell was used at a measurement temperature of 25° C. The obtained data was analyzed by the Smoluchowski formula to calculate the zeta potential (ζ potential) (mV) of the abrasive grains in the polishing composition.
(砥粒の粒子径の測定)
砥粒の平均一次粒子径(nm)は、マイクロメリテックス社製の“Flow SorbII 2300”を用いて測定されたBET法による砥粒の比表面積と、砥粒の密度とから算出した。また、砥粒の平均二次粒子径(nm)は、日機装株式会社製 動的光散乱式粒子径・粒度分布装置 UPA-UTI151により測定した。
(Measurement of abrasive grain size)
The average primary particle size (nm) of the abrasive grains was calculated from the specific surface area of the abrasive grains measured by the BET method using a Micromeritics "Flow SorbII 2300" and the density of the abrasive grains. The average secondary particle size (nm) of the abrasive grains was measured using a dynamic light scattering particle size/particle size distribution device UPA-UTI151 manufactured by Nikkiso Co., Ltd.
(砥粒の準備)
特開2005-162533号公報の実施例1に記載の方法と同様にして、シリカゾルのメタノール溶液(シリカ濃度=20質量%)1Lに対してシランカップリング剤としてγ-アミノプロピルトリエトキシシランを2mmolの濃度で使用して、平均一次粒子径:23nm、平均二次粒子径:50nm、アスペクト比:1.2、D90/D50:約1.4、平均会合度:2.17の繭型形状のカチオン変性コロイダルシリカを作製した。
(Preparation of abrasive grains)
In the same manner as in Example 1 of JP2005-162533A, γ-aminopropyltriethoxysilane was used as a silane coupling agent at a concentration of 2 mmol per 1 L of a methanol solution of silica sol (silica concentration=20% by mass), to prepare a cocoon-shaped cation-modified colloidal silica having an average primary particle size of 23 nm, an average secondary particle size of 50 nm, an aspect ratio of 1.2, a D90/D50 of approximately 1.4, and an average degree of association of 2.17.
また、アニオン変性シリカとして、スルホン酸修飾コロイダルシリカ(“Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003)に記載の方法で作製したもの、平均一次粒子径20nm、平均二次粒子径40nm、平均会合度2)を準備した。 As anion-modified silica, sulfonic acid-modified colloidal silica (produced by the method described in "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003), average primary particle size 20 nm, average secondary particle size 40 nm, average degree of association 2) was prepared.
(実施例1)
砥粒として上記で得られたカチオン変性コロイダルシリカを1質量%、式(1)の化合物として1,3-ジメチル尿素(東京化成工業株式会社製)を0.1質量%の最終濃度とそれぞれなるように、分散媒である純水に室温(25℃)で加え、混合液を得た。
Example 1
The cation-modified colloidal silica obtained above as the abrasive grains and 1,3-dimethylurea (manufactured by Tokyo Chemical Industry Co., Ltd.) as the compound of formula (1) were added to pure water as a dispersion medium at room temperature (25° C.) so as to have final concentrations of 1 mass % and 0.1 mass %, respectively, to obtain a mixed liquid.
その後、混合液に、pH調整剤として硝酸を、pHが4.0となるように添加し、室温(25℃)で30分攪拌混合し、研磨用組成物を調製した。研磨用組成物(液温:25℃)のpHは、pHメーター(株式会社堀場製作所製 型番:LAQUA)により確認した。また、得られた研磨用組成物中のカチオン変性コロイダルシリカのゼータ電位を、上記(砥粒のゼータ電位の測定)に従い測定したところ、+30mVであった。なお、研磨用組成物中のカチオン変性コロイダルシリカの粒子径は、用いたカチオン変性コロイダルシリカの粒子径と同様であった。さらに、得られた研磨用組成物の電気伝導度を、上記(研磨用組成物の電気伝導度の測定)に従い測定したところ、0.3mS/cmであった。 Then, nitric acid was added to the mixture as a pH adjuster so that the pH was 4.0, and the mixture was stirred and mixed at room temperature (25°C) for 30 minutes to prepare a polishing composition. The pH of the polishing composition (liquid temperature: 25°C) was confirmed with a pH meter (Model: LAQUA, manufactured by Horiba, Ltd.). The zeta potential of the cation-modified colloidal silica in the obtained polishing composition was measured according to the above (measurement of the zeta potential of the abrasive grains) and was +30 mV. The particle diameter of the cation-modified colloidal silica in the polishing composition was the same as the particle diameter of the cation-modified colloidal silica used. The electrical conductivity of the obtained polishing composition was measured according to the above (measurement of the electrical conductivity of the polishing composition) and was 0.3 mS/cm.
(実施例2~8、比較例1~5)
砥粒の種類および濃度、式(1)の化合物の種類および濃度、ならびに研磨用組成物のpHを、下記表1のように変更したこと以外は、実施例1と同様にして、実施例2~8、比較例1~5の各研磨用組成物を調製した。なお、1-メチル尿素として、東京化成工業株式会社製の1-メチル尿素を使用した。テトラメチル尿素として、東京化成工業株式会社製のテトラメチル尿素を使用した。下記表1において「-」と表示されているものは、その剤を含んでいないことを示す。
(Examples 2 to 8, Comparative Examples 1 to 5)
Polishing compositions of Examples 2 to 8 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1, except that the type and concentration of abrasive grains, the type and concentration of the compound of formula (1), and the pH of the polishing composition were changed as shown in Table 1 below. As 1-methylurea, 1-methylurea manufactured by Tokyo Chemical Industry Co., Ltd. was used. As tetramethylurea, tetramethylurea manufactured by Tokyo Chemical Industry Co., Ltd. was used. In Table 1 below, "-" indicates that the agent was not contained.
また、上記各研磨用組成物につき、実施例1と同様にして、研磨用組成物中の砥粒のゼータ電位および研磨用組成物の電気伝導度を測定し、結果を下記表1に示す。なお、各研磨用組成物中のカチオン変性コロイダルシリカの粒子径は、用いたカチオン変性コロイダルシリカの粒子径と同様であった。 In addition, for each of the above polishing compositions, the zeta potential of the abrasive grains in the polishing composition and the electrical conductivity of the polishing composition were measured in the same manner as in Example 1, and the results are shown in Table 1 below. The particle size of the cation-modified colloidal silica in each polishing composition was the same as the particle size of the cation-modified colloidal silica used.
比較例4は、式(1)の化合物の代わりに尿素(東京化成工業株式会社製)を用い、比較例5は式(1)の化合物の代わりにビ尿素(東京化成工業株式会社製)を用いた。 In Comparative Example 4, urea (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the compound of formula (1), and in Comparative Example 5, biurea (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the compound of formula (1).
<評価>
上記で得られた各研磨用組成物を用いて、下記の研磨対象物のいずれかに対して、以下の研磨条件で研磨した際の研磨速度を測定した。
<Evaluation>
Each of the polishing compositions obtained above was used to measure the removal rate when polishing any of the following objects to be polished under the following polishing conditions.
(研磨装置および研磨条件)
研磨装置:アプライド・マテリアルズ製200mm用CMP片面研磨装置 Mirra 研磨パッド:ニッタ・ハース株式会社製 硬質ポリウレタンパッド IC1010
研磨圧力:3psi(1psi=6894.76Pa)
研磨定盤回転数:97rpm
ヘッド(キャリア)回転数:43rpm
研磨用組成物の供給:掛け流し
研磨用組成物供給量:200mL/分
研磨時間:60秒。
(Polishing Equipment and Polishing Conditions)
Polishing equipment: Applied Materials 200 mm CMP single-sided polishing equipment Mirra Polishing pad: Nitta Haas Co., Ltd. hard polyurethane pad IC1010
Polishing pressure: 3 psi (1 psi = 6894.76 Pa)
Polishing platen rotation speed: 97 rpm
Head (carrier) rotation speed: 43 rpm
Supply of polishing composition: flowing Polishing composition supply amount: 200 mL/min Polishing time: 60 seconds.
(研磨対象物)
表面に研磨対象物の膜を形成したシリコンウェーハ(200mm、ブランケットウェーハ、アドバンテック株式会社製)をそれぞれ準備した。研磨対象物は、
(1)表面に厚さ5000Åのポリシリコン膜を形成したシリコンウェーハ(poly-Si)、
(2)表面に厚さ10000Åの酸化ケイ素(TEOS)膜を形成したシリコンウェーハ(TEOS)、および
(3)表面に厚さ2000Åの窒化ケイ素膜を形成したシリコンウェーハ(SiN)
の3種類とした。上記で得られた各研磨用組成物を用いて、上記3種の基板を上記の研磨条件で研磨した。
(Object to be polished)
Silicon wafers (200 mm, blanket wafer, manufactured by Advantec Co., Ltd.) with a film of the object to be polished formed on the surface were prepared.
(1) a silicon wafer (poly-Si) having a polysilicon film of 5000 Å formed on its surface;
(2) A silicon wafer (TEOS) having a 10,000 Å thick silicon oxide (TEOS) film formed on its surface, and (3) A silicon wafer (SiN) having a 2,000 Å thick silicon nitride film formed on its surface.
The above three types of substrates were polished under the above polishing conditions using each of the polishing compositions obtained above.
(研磨速度)
研磨速度(研磨レート)(Å/分)は、以下の式により計算した。
(Polishing speed)
The polishing speed (polishing rate) (Å/min) was calculated according to the following formula.
膜厚(Å)は、光学式膜厚測定器(ASET-f5x:ケーエルエー・テンコール社製)により求めて、研磨前後の膜厚の差を研磨時間で除することにより、研磨速度(研磨レート)(Å/分)を評価した。なお、下記表1では、ポリシリコンの研磨速度、窒化ケイ素の研磨速度および酸化ケイ素の研磨速度を、それぞれ、「poly-Si」、「SiN」および「TEOS」の欄に記す。 The film thickness (Å) was measured using an optical film thickness measuring device (ASET-f5x: manufactured by KLA Tencor Corporation), and the polishing speed (polishing rate) (Å/min) was evaluated by dividing the difference in film thickness before and after polishing by the polishing time. In Table 1 below, the polishing speeds for polysilicon, silicon nitride, and silicon oxide are shown in the "poly-Si", "SiN", and "TEOS" columns, respectively.
(選択比)
窒化ケイ素に対するポリシリコンの選択比は、ポリシリコンの研磨速度を窒化ケイ素の研磨速度で除することによって求める。また、酸化ケイ素に対するポリシリコンの選択比は、ポリシリコンの研磨速度を酸化ケイ素の研磨速度で除することによって求める。下記表1では、窒化ケイ素に対するポリシリコンの選択比および酸化ケイ素に対するポリシリコンの選択比を、それぞれ、「poly-Si/SiN」および「poly-Si/TEOS」の欄に記す。
(Selectivity)
The selectivity of polysilicon to silicon nitride is determined by dividing the polishing rate of polysilicon by the polishing rate of silicon nitride. The selectivity of polysilicon to silicon oxide is determined by dividing the polishing rate of polysilicon by the polishing rate of silicon oxide. In Table 1 below, the selectivity of polysilicon to silicon nitride and the selectivity of polysilicon to silicon oxide are shown in the "poly-Si/SiN" and "poly-Si/TEOS" columns, respectively.
各評価結果を下記表1に示す。なお、下記表1において、混合比は、各研磨用組成物における、砥粒 100質量部に対する式(1)の化合物量(質量部)の割合(質量比)である。例えば、下記表1において、実施例1の研磨用組成物は、カチオン変性コロイダルシリカ 100質量部に対して、式(1)の化合物であるジメチル尿素を10質量部含むことを意味する。 The evaluation results are shown in Table 1 below. In Table 1 below, the mixing ratio is the ratio (mass ratio) of the amount (parts by mass) of the compound of formula (1) to 100 parts by mass of abrasive grains in each polishing composition. For example, in Table 1 below, the polishing composition of Example 1 means that it contains 10 parts by mass of dimethylurea, which is the compound of formula (1), to 100 parts by mass of cation-modified colloidal silica.
上記表1から明らかなように、実施例1~8の研磨用組成物は、比較例1~5の研磨用組成物に比べて、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(poly-Si/SiN)が有意に高いことが分かる。また、実施例1~8の研磨用組成物は、比較例1~5の研磨用組成物に比べて、ポリシリコンの研磨速度が有意に高いことが分かる。特に、実施例3、4の研磨用組成物は、窒化ケイ素の研磨速度に対するポリシリコンの研磨速度の比(poly-Si/SiN)に優れ、また、高いポリシリコンの研磨速度および高い選択比(poly-Si/SiN)を両立していた。 As is clear from Table 1 above, the polishing compositions of Examples 1 to 8 have a significantly higher ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (poly-Si/SiN) than the polishing compositions of Comparative Examples 1 to 5. It is also clear that the polishing compositions of Examples 1 to 8 have a significantly higher polishing rate of polysilicon than the polishing compositions of Comparative Examples 1 to 5. In particular, the polishing compositions of Examples 3 and 4 have an excellent ratio of the polishing rate of polysilicon to the polishing rate of silicon nitride (poly-Si/SiN), and also achieve both a high polishing rate of polysilicon and a high selectivity ratio (poly-Si/SiN).
また、実施例1~8の研磨用組成物は、比較例1~5の研磨用組成物に比べて、酸化ケイ素(TEOS)の研磨速度に対するポリシリコンの研磨速度の比(poly-Si/TEOS)が1に近い値を示すことが分かった。このことは、実施例1~8の研磨用組成物が、酸化ケイ素をポリシリコンと同様の研磨速度で研磨し得ることを示している。 In addition, it was found that the polishing compositions of Examples 1 to 8 exhibited a ratio of the polishing rate of polysilicon to the polishing rate of silicon oxide (TEOS) (poly-Si/TEOS) that was closer to 1 than the polishing compositions of Comparative Examples 1 to 5. This indicates that the polishing compositions of Examples 1 to 8 can polish silicon oxide at the same polishing rate as polysilicon.
Claims (9)
式(1):N(R1)(R2)-C(=O)-N(R3)(R4)(式中、R1~R4は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R1~R4の少なくとも2つは、炭素数1~3のアルキル基を表す)で示される構造を有する化合物と、を含み、
pHが6.0未満である、研磨用組成物。 an abrasive having a positive zeta potential;
and a compound having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and in this case, at least two of R 1 to R 4 represent an alkyl group having 1 to 3 carbon atoms);
A polishing composition having a pH of less than 6.0.
式(1):N(R 1 )(R 2 )-C(=O)-N(R 3 )(R 4 )(式中、R 1 ~R 4 は、それぞれ独立して、水素原子または炭素数1~4のアルキル基を表し、この際、R 1 ~R 4 の少なくとも1つは、炭素数1~4のアルキル基を表す)で示される構造を有する化合物と、を含み、
pHが6.0未満であり、
ポリシリコンを含む研磨対象物を研磨するために用いられる、研磨用組成物。 an abrasive having a positive zeta potential;
and a compound having a structure represented by formula (1): N(R 1 )(R 2 )-C(═O)-N(R 3 )(R 4 ) (wherein R 1 to R 4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R 1 to R 4 represents an alkyl group having 1 to 4 carbon atoms);
The pH is less than 6.0,
A polishing composition used for polishing an object containing polysilicon .
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JP2007273910A (en) | 2006-03-31 | 2007-10-18 | Fujifilm Corp | Polishing composition liquid |
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WO2018131341A1 (en) | 2017-01-11 | 2018-07-19 | 株式会社フジミインコーポレーテッド | Polishing composition |
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JP2015193714A (en) | 2014-03-31 | 2015-11-05 | 株式会社フジミインコーポレーテッド | Composition for polishing |
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