JP2017063190A - Slurry and polishing method of substrate using the same - Google Patents
Slurry and polishing method of substrate using the same Download PDFInfo
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- JP2017063190A JP2017063190A JP2016181253A JP2016181253A JP2017063190A JP 2017063190 A JP2017063190 A JP 2017063190A JP 2016181253 A JP2016181253 A JP 2016181253A JP 2016181253 A JP2016181253 A JP 2016181253A JP 2017063190 A JP2017063190 A JP 2017063190A
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Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/31051—Planarisation of the insulating layers
- H01L21/31053—Planarisation of the insulating layers involving a dielectric removal step
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Materials Engineering (AREA)
Abstract
Description
本発明は、スラリー及びこれを用いた基板の研磨方法に係り、さらに詳しくは、半導体の製造工程における化学的・機械的な研磨工程を行うに当たって酸化物を効率よく研磨することのできるスラリー及びこれを用いた基板の研磨方法に関する。 The present invention relates to a slurry and a substrate polishing method using the same, and more specifically, a slurry capable of efficiently polishing an oxide in performing a chemical / mechanical polishing step in a semiconductor manufacturing process, and the same. The present invention relates to a method for polishing a substrate using a substrate.
半導体素子のサイズが益々縮小されると共に金属配線の層数が益々増大されることに伴い、各層における表面ばらつきは次の層に転写されて最下層表面の曲がり度が非常に重要になってきている。このような曲がりは、後続工程であるフォトリソグラフィ（ｐｈｏｔｏｌｉｔｈｏｇｒａｐｈｙ）工程を行い難いほど深刻な影響を及ぼす虞がある。従って、半導体素子の歩留まりを向上させるためには、半導体の製造工程における各種の工程時に発生するばらついた表面の曲がりを除去する平坦化工程を行うことが必須である。平坦化方法としては、薄膜を形成した後にリフロー（ｒｅｆｌｏｗ）させる方法、薄膜を形成した後にエッチバック（ｅｔｃｈ ｂａｃｋ）する方法、化学的・機械的な研磨（ｃｈｅｍｉｃａｌ ｍｅｃｈａｎｉｃａｌ ｐｏｌｉｓｈｉｎｇ：ＣＭＰ）を行う方法など種々の方法が挙げられる。 As the size of the semiconductor element is further reduced and the number of metal wiring layers is increased, the surface variation in each layer is transferred to the next layer, and the curvature of the bottom surface becomes very important. Yes. Such a bend may have a serious effect that it is difficult to perform a photolithography process, which is a subsequent process. Therefore, in order to improve the yield of the semiconductor element, it is essential to perform a planarization process for removing the uneven surface curvature that occurs during various processes in the semiconductor manufacturing process. As a planarization method, a method of performing reflow after forming a thin film, a method of performing etch back after forming a thin film, a method of performing chemical mechanical polishing (CMP), etc. There are various methods.
化学的・機械的な研磨工程とは、半導体基板の表面を研磨パッドに押し当てて回転運動を行いながら、研磨剤と各種の化合物が含有されているスラリーを提供して平らに研磨を行う工程のことをいう。すなわち、基板やその上部の層の表面がスラリー及び研磨パッドにより化学的及び機械的に研磨されて平坦化されることをいう。 The chemical / mechanical polishing process is a process in which the surface of the semiconductor substrate is pressed against the polishing pad and rotated to provide a slurry containing an abrasive and various compounds and polished flat. I mean. That is, the surface of the substrate and the upper layer thereof is planarized by being chemically and mechanically polished by a slurry and a polishing pad.
例えば、既存のフラッシュメモリ素子の製造過程において素子分離膜を形成するために、ポリシリコン膜を研磨停止膜としてシリコン酸化膜を化学的・機械的に研磨する工程が用いられる。すなわち、基板の上部にゲート絶縁膜及びポリシリコン膜を形成した後、ポリシリコン膜の上に窒化膜をハードマスクとして用いて基板を所定の深さでエッチングしてトレンチを形成する。次いで、トレンチが埋め込まれるようにシリコン酸化膜を形成した後、ポリシリコン膜が露出されるまでシリコン酸化膜を研磨して素子分離膜を形成する。 For example, a process of chemically and mechanically polishing a silicon oxide film using a polysilicon film as a polishing stopper film is used to form an element isolation film in the manufacturing process of an existing flash memory element. That is, after forming a gate insulating film and a polysilicon film on the substrate, a trench is formed on the polysilicon film by etching the substrate at a predetermined depth using a nitride film as a hard mask. Next, after forming a silicon oxide film so as to fill the trench, the silicon oxide film is polished until the polysilicon film is exposed to form an element isolation film.
このため、これらの複数の異種物質層にトレンチを形成し、その内部にシリコン酸化膜を形成するためには、酸化物に対する高い研磨率を有するだけではなく、窒化膜及びポリシリコン膜の研磨を同時に抑える最適な研磨選択比を有するスラリーが求められる。 For this reason, in order to form trenches in these plurality of different material layers and form a silicon oxide film therein, not only has a high polishing rate for oxides, but also polishes nitride films and polysilicon films. There is a need for a slurry having an optimum polishing selectivity that is simultaneously suppressed.
しかしながら、これまでは酸化物に対する研磨選択比を向上させるための種々の研究が行われているだけであり、酸化物の研磨率をより低い研磨率に下げて窒化膜及びポリシリコン膜に対して最適な研磨選択比を調節するための酸化物研磨用スラリーは開発されていないのが現状である。 However, only various studies have been conducted so far to improve the polishing selectivity ratio with respect to the oxide, and the polishing rate of the oxide is lowered to a lower polishing rate and the nitride film and the polysilicon film are reduced. At present, an oxide polishing slurry for adjusting an optimum polishing selection ratio has not been developed.
一方、シリコン窒化膜の研磨を抑えて酸化物に対する研磨選択比を向上させるシリコン窒化物研磨用スラリーが提案されているが（例えば、下記の特許文献１参照）、この場合にも、窒化物に対する酸化物の研磨選択比のみを向上させるだけであり、上述した問題は依然として存在する。
On the other hand, a silicon nitride polishing slurry that suppresses polishing of the silicon nitride film and improves the polishing selectivity to oxide has been proposed (see, for example,
本発明の目的は、酸化物研磨用スラリー及びこれを用いた基板の研磨方法を提供することである。より詳細に言えば、本発明の目的は、酸化物及び酸化物以外の物質の研磨率を調節して研磨選択比を最適な範囲に維持することのできるスラリー及び基板の研磨方法を提供することにある。 An object of the present invention is to provide an oxide polishing slurry and a method for polishing a substrate using the same. More specifically, an object of the present invention is to provide a slurry and a substrate polishing method capable of maintaining the polishing selectivity within an optimum range by adjusting the polishing rate of oxides and substances other than oxides. It is in.
本発明の実施形態に係るスラリーは、酸化物の研磨用スラリーであって、研磨を行う研磨剤と、前記研磨剤を分散させる分散剤及び前記酸化物とは異なる第１の物質の研磨を抑える第１の研磨抑制剤を含む第１のスラリーと、前記酸化物の研磨を促す研磨促進剤を含む第２のスラリーと、を含む。 The slurry according to the embodiment of the present invention is an oxide polishing slurry, and suppresses polishing of a polishing agent for polishing, a dispersing agent for dispersing the polishing agent, and a first substance different from the oxide. A first slurry containing a first polishing inhibitor; and a second slurry containing a polishing accelerator that promotes polishing of the oxide.
前記第２のスラリーは、前記酸化物及び前記第１の物質とは異なる第２の物質の研磨を抑える第２の研磨抑制剤を含んでいてもよい。 The second slurry may include a second polishing inhibitor that suppresses polishing of the second substance different from the oxide and the first substance.
前記第１のスラリー及び第２のスラリーは、１：０．５〜１：１．５の割合で混合されてもよい。 The first slurry and the second slurry may be mixed at a ratio of 1: 0.5 to 1: 1.5.
前記研磨剤は、酸化セリウム（セリア）粒子を含み、前記第１のスラリーの総質量に対して、０．１質量％〜１０質量％で含まれることができる。 The abrasive may include cerium oxide (ceria) particles, and may be included at 0.1 mass% to 10 mass% with respect to the total mass of the first slurry.
前記酸化物対前記第１の物質の研磨選択比は、１００：１〜３００：１の範囲であり、前記酸化物対前記第２の物質の研磨選択比は、２０：１〜６０：１の範囲であってもよい。 The polishing selectivity ratio of the oxide to the first material ranges from 100: 1 to 300: 1, and the polishing selectivity ratio of the oxide to the second material ranges from 20: 1 to 60: 1. It may be a range.
前記第１の研磨抑制剤の含有量は、前記研磨促進剤の含有量よりも少なくてもよい。 The content of the first polishing inhibitor may be less than the content of the polishing accelerator.
前記第１の研磨抑制剤の含有量は、前記第２の研磨抑制剤の含有量よりも少なくてもよい。 The content of the first polishing inhibitor may be less than the content of the second polishing inhibitor.
前記第１の研磨抑制剤は、前記第１のスラリーの総質量に対して、０．００２質量％〜０．０２質量％で含まれることができる。 The first polishing inhibitor may be included at 0.002% by mass to 0.02% by mass with respect to the total mass of the first slurry.
前記研磨促進剤は、前記第２のスラリーの総質量に対して、０．１質量％〜１．３５質量％で含まれることができる。 The polishing accelerator may be included at 0.1% by mass to 1.35% by mass with respect to the total mass of the second slurry.
前記第２の研磨抑制剤は、前記第２のスラリーの総質量に対して、０．１５質量％〜１質量％で含まれることができる。 The second polishing inhibitor may be included at 0.15% by mass to 1% by mass with respect to the total mass of the second slurry.
前記第１の研磨抑制剤は、疎水性基及び親水性基を両方とも有するノニオン系物質を含んでいてもよい。 The first polishing inhibitor may contain a nonionic substance having both a hydrophobic group and a hydrophilic group.
前記第１の研磨抑制剤は、ポリプロピレングリコール−ポリエチレングリコール−ポリプロピレングリコール共重合体（ＰＥＰ）、ポリソルベート、オクトキシノール、ポリエチレングリコールオクタデシルエーテル、ノニルフェノールエトキシレート、エチレンオキシド、グリコール酸、グリセロールエトキシレートのうちの少なくとも一種を含んでいてもよい。 The first polishing inhibitor is a polypropylene glycol-polyethylene glycol-polypropylene glycol copolymer (PEP), polysorbate, octoxynol, polyethylene glycol octadecyl ether, nonylphenol ethoxylate, ethylene oxide, glycolic acid, glycerol ethoxylate. At least one kind may be included.
前記研磨促進剤は、ヒドロキシル基及びアミン基を有しているアルカノールアミン系の単分子物質を含んでいてもよい。 The polishing accelerator may contain an alkanolamine-based monomolecular substance having a hydroxyl group and an amine group.
前記研磨促進剤は、アミノメチルプロパノール（ＡＭＰ）、エタノールアミン、ヘプタミノール、イソエタリン、メタノールアミン、ジエチルエタノールアミン及びＮ−メチルエタノールアミンのうちの少なくとも一種を含んでいてもよい。 The polishing accelerator may contain at least one of aminomethyl propanol (AMP), ethanolamine, heptaminol, isoetarine, methanolamine, diethylethanolamine, and N-methylethanolamine.
前記第２の研磨抑制剤は、カルボキシル基を有するアニオン系物質を含んでいてもよい。 The second polishing inhibitor may contain an anionic substance having a carboxyl group.
前記第２の研磨抑制剤は、ポリアクリル酸（ＰＡＡ）、ポリアルキルメタクリレート、アクリルアミド、メタクリルアミド及びエチル−メタクリルアミドのうちの少なくとも一種を含んでいてもよい。 The second polishing inhibitor may contain at least one of polyacrylic acid (PAA), polyalkyl methacrylate, acrylamide, methacrylamide, and ethyl-methacrylamide.
本発明の実施形態に係る基板の研磨方法は、酸化物層及び酸化物以外の複数の異種物質により形成される異種物質層が形成された基板を設ける過程と、研磨剤と、前記研磨剤を分散させる分散剤及び前記複数の異種物質のうち第１の物質の研磨を抑える第１の研磨抑制剤を含む第１のスラリーを設ける過程と、前記酸化物の研磨を促す研磨促進剤及び前記複数の異種物質のうち第２の物質の研磨を抑える第２の研磨抑制剤を含む第２のスラリーを設ける過程と、前記第１のスラリー及び第２のスラリーを前記基板の上に供給しながら前記酸化物層を研磨する過程と、を含む。 A method for polishing a substrate according to an embodiment of the present invention includes a process of providing a substrate on which an oxide layer and a heterogeneous material layer formed of a plurality of different materials other than oxide are provided, an abrasive, and the abrasive A step of providing a first slurry containing a dispersing agent to be dispersed and a first polishing inhibitor that suppresses polishing of the first substance among the plurality of different substances; a polishing accelerator that promotes polishing of the oxide; A step of providing a second slurry containing a second polishing inhibitor that suppresses polishing of the second substance among the different kinds of substances, and supplying the first slurry and the second slurry onto the substrate. Polishing the oxide layer.
前記基板を設ける過程は、前記基板の上に前記第１の物質により形成される第１の物質層を形成する過程と、前記第１の物質層の上に前記第２の物質により形成される第２の物質層を形成する過程と、前記第１の物質層及び第２の物質層にトレンチを形成する過程と、前記トレンチを有する全面の上に酸化物層を形成する過程と、を含んでいてもよい。 The step of providing the substrate includes a step of forming a first material layer formed of the first material on the substrate, and a step of forming the second material on the first material layer. Forming a second material layer, forming a trench in the first material layer and the second material layer, and forming an oxide layer on the entire surface having the trench. You may go out.
前記研磨過程は、前記酸化物層の研磨速度を前記第２の物質の研磨速度よりも速くしてもよく、前記第２の物質の研磨速度を前記第１の物質の研磨速度よりも速くしてもよい。 In the polishing process, the polishing rate of the oxide layer may be higher than the polishing rate of the second material, and the polishing rate of the second material may be higher than the polishing rate of the first material. May be.
前記研磨過程は、前記酸化物対前記第１の物質の研磨選択比を１００：１〜３００：１の範囲に維持し、前記酸化物対前記第２の物質の研磨選択比を２０：１〜６０：１の範囲に維持してもよい。 The polishing process maintains a polishing selectivity ratio of the oxide to the first material in a range of 100: 1 to 300: 1, and a polishing selectivity ratio of the oxide to the second material of 20: 1 to 1. You may maintain in the range of 60: 1.
前記研磨過程は、前記第１のスラリー及び第２のスラリーを１：０．５〜１：１．５の割合で混合して前記基板の上に供給してもよい。 In the polishing process, the first slurry and the second slurry may be mixed at a ratio of 1: 0.5 to 1: 1.5 and supplied onto the substrate.
本発明の実施形態によれば、第１の研磨抑制剤を含む第１のスラリー及び研磨促進剤を含む第２のスラリーを混合したスラリーを用いることから、酸化物に対する高い研磨率を有するだけではなく、酸化物以外の物質、例えば、ポリシリコンまたは窒化物の研磨率を最適な範囲に調節することができる。なお、酸化物以外の複数の異なる物質に対してそれぞれ高選択比を有するように調節を行うとともに、所定のレベルの研磨率差を有するように異なる各物質に対する研磨選択比をそれぞれ調節して研磨安定性を向上させることができる。 According to the embodiment of the present invention, since a slurry obtained by mixing the first slurry containing the first polishing inhibitor and the second slurry containing the polishing accelerator is used, it is only necessary to have a high polishing rate for the oxide. In addition, the polishing rate of a substance other than an oxide, for example, polysilicon or nitride can be adjusted to an optimum range. In addition, adjustment is performed so that each of a plurality of different substances other than oxides has a high selection ratio, and polishing is performed by adjusting the polishing selection ratio for each different substance so as to have a predetermined level of polishing rate difference Stability can be improved.
また、第１の研磨抑制剤は、酸化物の研磨率を緩やかに下げて酸化物の研磨率が調節しやすいだけではなく、ポリシリコンの上にパッシベーション膜を形成してポリシリコン膜が研磨されることを防ぐことができて、オーバーエッチングを防ぐことができる。 The first polishing inhibitor not only easily adjusts the oxide polishing rate by gradually reducing the oxide polishing rate, but also forms a passivation film on the polysilicon to polish the polysilicon film. This can prevent over-etching.
例えば、半導体素子の製造工程において研磨停止膜として用いられるポリシリコン膜の上に窒化膜をマスクとして用いて基板を所定の深さでエッチングする場合、このような各異種物質層に対して酸化膜の研磨選択比を向上させることができる。なお、酸化膜の各物質層に対する研磨選択比を最適な範囲に維持してエロージョン及びディッシングを抑え、一回の工程を用いて研磨工程を終えることができて、工程の単純化及びコストの節減による生産性の向上を図ることができる。 For example, when a substrate is etched at a predetermined depth using a nitride film as a mask on a polysilicon film used as a polishing stopper film in a semiconductor device manufacturing process, an oxide film is formed for each of these different material layers. The polishing selection ratio can be improved. It should be noted that the polishing selectivity ratio for each material layer of the oxide film is maintained within an optimal range to suppress erosion and dishing, and the polishing process can be completed using a single process, thereby simplifying the process and reducing costs. This can improve productivity.
本発明によるスラリー及びこれを用いた基板の研磨方法は、第１の研磨抑制剤を含む第１のスラリー及び研磨促進剤を含む第２のスラリーを混合したスラリーを用いることにより、酸化物（ＳｉＯ２）に対する高い研磨率を有するだけではなく、酸化物以外の物質、例えば、ポリシリコン（ｐｏｌｙ−Ｓｉ）または窒化物（Ｓｉ３Ｎ４）の研磨率を最適な範囲に調節することができるという技術的な特徴を提示する。 The slurry according to the present invention and the method for polishing a substrate using the same use an oxide (SiO 2) by using a slurry obtained by mixing a first slurry containing a first polishing inhibitor and a second slurry containing a polishing accelerator. 2 ) In addition to having a high polishing rate with respect to 2 ), the polishing rate of materials other than oxides, for example, polysilicon (poly-Si) or nitride (Si 3 N 4 ) can be adjusted to an optimum range. Present technical features.
以下、添付図面に基づき、本発明の実施形態について詳細に説明する。しかしながら、本発明は以下に開示される実施形態に何ら限定されるものではなく、異なる様々な形態として実現され、単にこれらの実施形態は本発明の開示を完全たるものにし、通常の知識を有する者に発明の範囲を完全に知らせるために提供されるものである。図中、同じ符号は同じ構成要素を示す。また、図１〜１０中の「ｗｔ％」は質量％を表すものとする。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be realized in various different forms, which merely complete the disclosure of the present invention and have ordinary knowledge. It is provided to fully inform the person of the scope of the invention. In the drawings, the same reference numerals indicate the same components. Further, “wt%” in FIGS. 1 to 10 represents mass%.
本発明の実施形態によるスラリーは、酸化物研磨用スラリーであって、研磨を行う研磨剤及び前記酸化物とは異なる第１の物質の研磨を抑える第１の研磨抑制剤を含む第１のスラリーと、前記酸化物の研磨を促す研磨促進剤を含む第２のスラリーと、を含む。ここで、第１のスラリーは、前記研磨剤を分散させる分散剤を含んでいてもよく、前記研磨剤の分散を均一に維持する分散安定剤をさらに含んでいてもよい。なお、第２のスラリーは、前記酸化物とは異なる第２の物質の研磨を抑える第２の研磨抑制剤を含んでいてもよい。 The slurry according to the embodiment of the present invention is a slurry for polishing an oxide, and includes a polishing agent that performs polishing and a first polishing inhibitor that suppresses polishing of a first substance different from the oxide. And a second slurry containing a polishing accelerator that promotes polishing of the oxide. Here, the first slurry may include a dispersant for dispersing the abrasive, and may further include a dispersion stabilizer for maintaining the dispersion of the abrasive uniformly. Note that the second slurry may contain a second polishing inhibitor that suppresses polishing of the second substance different from the oxide.
第１のスラリーに含まれる研磨剤、分散剤、分散安定剤、第１の研磨抑制剤は、第１の溶液内に含有されてもよい。例えば、水、特に、純水（ＤＩ ｗａｔｅｒ）に研磨剤、分散剤、分散安定剤及び第１の研磨抑制剤が分散されて分布する。なお、第１のスラリーのｐＨを調節するために、第１のｐＨ調節剤がさらに含まれていてもよい。このような第１のスラリーは、液体に研磨剤が分散された状態のものであり、各成分の含量が適切に調節される。 The abrasive, dispersant, dispersion stabilizer, and first polishing inhibitor contained in the first slurry may be contained in the first solution. For example, an abrasive, a dispersant, a dispersion stabilizer, and a first polishing inhibitor are dispersed and distributed in water, particularly pure water (DI water). In addition, in order to adjust pH of a 1st slurry, the 1st pH adjuster may further be contained. Such a first slurry is in a state where an abrasive is dispersed in a liquid, and the content of each component is appropriately adjusted.
また、第２のスラリーに含まれる研磨促進剤及び第２の研磨抑制剤は、第２の溶液内に含有されてもよい。すなわち、水、特に、純水に研磨促進剤及び第２の研磨抑制剤が分散されて分布し、第２のスラリーのｐＨを調節するために第２のｐＨ調節剤がさらに含まれていてもよい。 Moreover, the polishing accelerator and the second polishing inhibitor contained in the second slurry may be contained in the second solution. That is, even if the polishing accelerator and the second polishing inhibitor are dispersed and distributed in water, particularly pure water, and a second pH adjuster is further included to adjust the pH of the second slurry. Good.
ここで、第１のスラリー及び第２のスラリーは、希釈剤とともに混合されて酸化物研磨用スラリーとして研磨対象物の表面に供給され、希釈剤は、水、特に、純水であってもよい。第１のスラリーに含まれる研磨剤、分散剤、分散安定剤及び第１の研磨抑制剤、及び第２のスラリーに含まれる研磨促進剤及び第２の研磨抑制剤は、一つのスラリーとして製造されてもよいが、研磨剤、分散剤、分散安定剤及び第１の研磨抑制剤を含む第１のスラリー、及び研磨促進剤及び第２の研磨抑制剤を含む第２のスラリーとしてそれぞれ製造されて研磨前に希釈剤とともに混合されて研磨対象物に供給されてもよい。これは、第１のスラリー及び第２のスラリーを使い分けずに長期に亘って繰り返し研磨工程を行う場合、第２のスラリーの研磨促進剤及び第２の研磨抑制剤のイオン性によりスラリーの分散安定性が低下し、しかも、有効使用期間が短縮される虞があるためである。 Here, the first slurry and the second slurry are mixed together with a diluent and supplied to the surface of the object to be polished as an oxide polishing slurry, and the diluent may be water, particularly pure water. . The polishing agent, the dispersing agent, the dispersion stabilizer and the first polishing inhibitor contained in the first slurry, and the polishing accelerator and the second polishing inhibitor contained in the second slurry are produced as one slurry. The first slurry containing the polishing agent, the dispersing agent, the dispersion stabilizer and the first polishing inhibitor, and the second slurry containing the polishing accelerator and the second polishing inhibitor, respectively. It may be mixed with a diluent before polishing and supplied to the object to be polished. This is because when the polishing process is repeatedly performed over a long period of time without properly using the first slurry and the second slurry, the dispersion of the slurry is stabilized by the ionicity of the polishing accelerator and the second polishing inhibitor of the second slurry. This is because there is a risk that the effective use period may be shortened.
研磨剤は、シリカ（ＳｉＯ２）、セリア（ＣｅＯ２）、アルミナ（Ａｌ２Ｏ３）、チタニア（ＴｉＯ２）、ジルコニア（ＺｒＯ２）及びゲルマニア（ＧｅＯ２）よりなる群から選ばれる少なくとも一種の金属酸化物であってもよい。ここで、研磨剤は、酸化物の研磨選択比が高いセリア（ＣｅＯ２）を含んでいてもよい。 The abrasive is at least one selected from the group consisting of silica (SiO 2 ), ceria (CeO 2 ), alumina (Al 2 O 3 ), titania (TiO 2 ), zirconia (ZrO 2 ), and germania (GeO 2 ). It may be a metal oxide. Here, the abrasive may contain ceria (CeO 2 ) having a high oxide selectivity.
また、前記研磨剤は、第１のスラリー１００質量％を基準として０．１〜１０質量％で含まれていてもよい。研磨剤が０．１質量％未満で含まれると、研磨の効果があまり得られず、１０質量％を超えて含まれると、研磨率が高すぎて対象膜の過剰な研磨が行われる虞があり、しかも、傷つきが発生する虞がある。 Moreover, the said abrasive | polishing agent may be contained by 0.1-10 mass% on the basis of 100 mass% of 1st slurries. If the abrasive is contained in an amount of less than 0.1% by mass, the effect of polishing is not obtained so much that if it is contained in excess of 10% by mass, the polishing rate may be too high and the target film may be excessively polished. In addition, there is a risk of scratching.
前記研磨剤を構成する研磨粒子は、Ｘ線回折（ｘ−ｒａｙ ｄｉｆｆｒａｃｔｉｏｎ：ＸＲＤ）を用いて結晶構造を分析することができ、湿式セリアと同じ結晶構造を有し、多面体の結晶面を有する。 The abrasive particles constituting the abrasive can be analyzed for crystal structure using X-ray diffraction (XRD), have the same crystal structure as wet ceria, and have polyhedral crystal faces.
研磨粒子の平均粒径は、５〜１００ｎｍであってもよい。ここで、研磨粒子の平均粒径が５ｎｍ未満である場合、研磨対象膜が十分に研磨されないため研磨率が低くなり、研磨粒子の平均粒径が１００ｎｍを超えると、研磨対象膜にマイクロスクラッチを発生させる。なお、研磨剤を構成する研磨粒子の平均粒径は、２０〜８０ｎｍであってもよい。これは、研磨対象膜の研磨を低下させず、且つ研磨停止膜にマイクロスクラッチを発生させないためである。 The average particle size of the abrasive particles may be 5 to 100 nm. Here, when the average particle size of the abrasive particles is less than 5 nm, the polishing target film is not sufficiently polished, resulting in a low polishing rate. When the average particle size of the abrasive particles exceeds 100 nm, micro scratches are applied to the polishing target film. generate. The average particle diameter of the abrasive particles constituting the abrasive may be 20 to 80 nm. This is because the polishing of the polishing target film is not lowered and micro scratches are not generated in the polishing stopper film.
分散剤は、第１のスラリー内で研磨剤を均一に分散させて研磨粒子同士の凝集を防ぐ役割を果たし、カチオン系高分子物質、アニオン系低分子物質、ヒドロキシル基を含む酸またはアミノ基を含む酸を用いることができる。また、分散剤は、研磨剤のゼータ電位を調節することができる。すなわち、カチオン系分散剤は、研磨剤のゼータ電位をプラス、すなわち、正の電位に上げることができ、アニオン系分散剤は、研磨剤のゼータ電位をマイナス、すなわち、負の電位に下げることができる。このため、スラリーに含まれる分散剤に応じて研磨剤のゼータ電位をそのまま維持してもよく、正の電位または負の電位側に微細に調節してもよい。 The dispersant serves to prevent the agglomeration of the abrasive particles by uniformly dispersing the abrasive in the first slurry, and includes a cationic high-molecular substance, an anionic low-molecular substance, an acid or amino group containing a hydroxyl group. An acid can be used. The dispersant can adjust the zeta potential of the abrasive. That is, the cationic dispersant can increase the zeta potential of the abrasive to a positive, that is, positive potential, and the anionic dispersant can decrease the zeta potential of the abrasive to a negative, that is, a negative potential. it can. For this reason, the zeta potential of the abrasive may be maintained as it is according to the dispersant contained in the slurry, or may be finely adjusted to the positive potential or negative potential side.
カチオン系高分子分散剤としては、ポリリシン（Ｐｏｌｙｌｙｓｉｎｅ）、ポリエチレンイミン（Ｐｏｌｙｅｔｈｙｌｅｎｉｍｅ）、塩化ベンゼトニウム（Ｂｅｎｚｅｔｈｏｎｉｕｍ Ｃｈｌｏｒｉｄｅ）、臭化セトリモニウム（Ｃｅｔｒｉｍｏｎｉｕｍ ｂｒｏｍｉｄｅ）、塩化セトリモニウム（Ｃｅｔｒｉｍｏｎｉｕｍ ｃｈｌｏｒｉｄｅ）、水酸化テトラメチルアンモニウム（Ｔｅｔｒａｍｅｔｈｙｌａｍｍｏｎｉｕｍ ｈｙｄｒｏｘｉｄｅ）、ジステアリルジメチル塩化アンモニウム（Ｄｉｓｔｅａｒｙｌ ｄｉｍｅｔｈｙｌ ａｍｍｏｎｉｕｍ ｃｈｌｏｒｉｄｅ）、ジメチルアミン及びエピクロロヒドリンの重合物（Ｐｏｌｙｄｉｍｅｔｈｙｌａｍｉｎｅ−ｃｏ−ｅｐｉｃｈｌｏｒｏｈｙｄｒｉｎ）、ポリアリルアミン（Ｐｏｌｙ ａｌｌｙｌ ａｍｉｎｅ）よりなる群から選ばれる少なくとも一種が挙げられる。 Examples of the cationic polymer dispersant include polylysine, polyethylenimine, benzethonium chloride, cetrimonium bromide, cetrimonium ammonium hydroxide, and cetrimonium ammonium hydroxide. Tetramethylammonium hydroxide, distearyldimethylammonium chloride, polymer of dimethylamine and epichlorohydrin, polyallylamine (polyallylamine), polyallylamine (polyallylamine) and at least one selected from the group consisting of lylamine).
また、アニオン系低分子分散剤としては、シュウ酸（ｏｘａｌｉｃ ａｃｉｄ）、クエン酸（ｃｉｔｒｉｃ ａｃｉｄ）、多硫酸（ｐｏｌｙｓｕｌｆｕｒｉｃ ａｃｉｄ）、ポリアクリル酸（ｐｏｌｙａｃｒｙｌｉｃ ａｃｉｄ）、ポリメタクリル酸（Ｄａｒｖａｎ Ｃ−Ｎ）及びこれらの塩を少なくとも一種以上含有する物質よりなる群から選ばれる少なくとも一種が挙げられるか、或いは、これらの共重合体酸（ｃｏｐｏｌｙｍｅｒ ａｃｉｄ）が挙げられる。 Examples of the anionic low molecular weight dispersant include oxalic acid, citric acid, polysulfuric acid, polyacrylic acid, polymethacrylic acid (Darvan CN) and There may be mentioned at least one selected from the group consisting of substances containing at least one of these salts, or a copolymer acid thereof.
さらに、ヒドロキシル基を含む酸としては、ヒドロキシ安息香酸（ｈｙｄｒｏｘｙｌｂｅｎｚｏｉｃ ａｃｉｄ）、アスコルビン酸（ａｓｃｏｒｂｉｃ ａｃｉｄ）及びこれらの塩を少なくとも一種以上含有する物質よりなる群から選ばれる少なくとも一種が挙げられ、アミノ基を含む酸としては、ピコリン酸（ｐｉｃｏｌｉｎｉｃ ａｃｉｄ）、グルタミン酸（ｇｌｕｔａｍｉｃ ａｃｉｄ）、トリプトファン（ｔｒｙｐｔｏｐｈａｎｅ）、アミノ酪酸（ａｍｉｎｏｂｕｔｙｒｉｃ ａｃｉｄ）及びこれらの塩を少なくとも一種以上含有する物質よりなる群から選ばれる少なくとも一種が挙げられる。 Furthermore, examples of the acid containing a hydroxyl group include at least one selected from the group consisting of hydroxybenzoic acid, ascorbic acid, and a substance containing at least one of these salts. Examples of the acid to be contained include at least one selected from the group consisting of picolinic acid, glutamic acid, tryptophan, aminobutyric acid, and a substance containing at least one of these salts. It is done.
分散剤は、第１のスラリーの総質量に対して、０．０１質量％〜１質量％の範囲で含まれることができる。分散剤の含量が０．０１質量％未満であれば、分散され難く、沈殿が起こる虞があり、分散剤の含量が１質量％を超えると、高分子物質の凝集及び高いイオン化濃度によりスラリーの分散安定性が低下する虞がある。また、分散剤は、スラリーの総質量に対して、０．０５質量％〜０．３質量％の範囲で含まれることができる。これは、分散安定性に非常に優れているので、研磨剤のゼータ電位を微細に調節するのに一層有利であるからである。 The dispersant may be included in the range of 0.01% by mass to 1% by mass with respect to the total mass of the first slurry. If the content of the dispersant is less than 0.01% by mass, it is difficult to disperse and precipitation may occur. If the content of the dispersant exceeds 1% by mass, the aggregation of the polymer substance and the high ionization concentration cause the slurry. Dispersion stability may be reduced. Moreover, a dispersing agent can be contained in 0.05 mass%-0.3 mass% with respect to the gross mass of a slurry. This is because the dispersion stability is very excellent, and this is more advantageous for finely adjusting the zeta potential of the abrasive.
分散安定剤は、スラリー内においてｐＨ緩衝作用をすることにより、外部の変化因子による第１のスラリーの化学変化を抑えて研磨粒子同士の凝集を防ぎ、研磨粒子を均一に分散させて傷付きの発生を抑える役割を果たす。分散安定剤は有機酸を含んでいてもよく、この場合、解離定数の絶対値であるｐＫａ値が９〜１２であり、アミノ酸中においてカルボキシル基（ＣＯＯＨ）及びアミン基（ＮＨ２）が同じカーボン（Ｃ）原子に結合されているα−アミノ酸を含んでいてもよい。ここで、α−アミノ酸は、カルボキシル基（ＣＯＯＨ）及びアミン基（ＮＨ２）の数に応じて中性アミノ酸、酸性アミノ酸及び塩基性アミノ酸に分類可能であるが、中性アミノ酸は、同じ数のアミン基及びカルボキシル基を有するアラニン（Ａｌａｎｉｎｅ）、グリシン（Ｇｌｙｃｉｎｅ）、チロシン（Ｔｙｒｏｓｉｎｅ）及びバリン（Ｖａｌｉｎｅ）よりなる群から選ばれる少なくとも一種を含んでいてもよく、酸性アミノ酸は、カルボキシル基の数がアミン基の数よりも多い アスパラギン酸（Ａｓｐａｒｔｉｃ ａｃｉｄ）、グルタミン酸（Ｇｌｕｔａｍｉｃ ａｃｉｄ）及びクエン酸（Ｃｉｔｒｉｃ ａｃｉｄ）よりなる群から選ばれる少なくとも一種を含んでいてもよく、塩基性アミノ酸は、アミン基の数がカルボキシル基の数よりも多いリシン（Ｌｙｓｉｎｅ）を含んでいてもよい。 The dispersion stabilizer acts as a pH buffer in the slurry, thereby suppressing the chemical change of the first slurry due to an external change factor to prevent agglomeration of the abrasive particles and uniformly dispersing the abrasive particles. It plays a role in suppressing the occurrence. The dispersion stabilizer may contain an organic acid. In this case, the pKa value, which is the absolute value of the dissociation constant, is 9 to 12, and in the amino acid, the carboxyl group (COOH) and the amine group (NH 2 ) are the same carbon. (C) An α-amino acid bonded to an atom may be included. Here, α-amino acids can be classified into neutral amino acids, acidic amino acids, and basic amino acids according to the number of carboxyl groups (COOH) and amine groups (NH 2 ). It may contain at least one selected from the group consisting of alanine having a amine group and a carboxyl group, glycine, tyrosine, and valine, and the acidic amino acid has the number of carboxyl groups. The number of amine groups may include at least one selected from the group consisting of aspartic acid (Aspartic acid), glutamic acid (Glutamic acid) and citric acid (Citric acid). Is more than the number of carboxyl groups There may also contain lysine (Lysine).
分散安定剤は、第１のスラリーに含まれる研磨剤５質量％を基準として第１のスラリーの総質量に対して、０．００１質量％〜０．１質量％の範囲で含まれることができる。分散安定剤の含量が０．００１質量％未満であれば、分散安定剤のｐＨ緩衝能が低いため分散安定剤の効果が不十分であり、分散安定剤の含量が０．１質量％を超えると、研磨剤の分散安定性が低くなって沈殿が起こる虞がある。なお、分散安定剤は、スラリーの総質量に対して、０．００５質量％〜０．０５質量％の範囲で含まれることができる。これは、ｐＨ緩衝能に非常に優れているので、分散安定性を維持するのに一層有利であるからである。 The dispersion stabilizer may be included in the range of 0.001% by mass to 0.1% by mass with respect to the total mass of the first slurry based on 5% by mass of the abrasive contained in the first slurry. . If the content of the dispersion stabilizer is less than 0.001% by mass, the effect of the dispersion stabilizer is insufficient because the pH buffering ability of the dispersion stabilizer is low, and the content of the dispersion stabilizer exceeds 0.1% by mass. Then, the dispersion stability of the abrasive is lowered, and precipitation may occur. In addition, a dispersion stabilizer can be contained in 0.005 mass%-0.05 mass% with respect to the total mass of a slurry. This is because the pH buffering ability is very excellent, which is more advantageous for maintaining the dispersion stability.
第１の研磨抑制剤は、研磨対象以外の物質の研磨を抑える。すなわち、各物質の研磨を抑えて、研磨選択比を調節する。ここで、研磨対象以外の物質は、成分が異なる複数の異種物質を含んでいてもよい。例えば、酸化物を研磨する場合、第１の研磨抑制剤は、複数の異種物質に含まれる第１の物質及び第２の物質の研磨をそれぞれ抑えて選択比を調節してもよい。 The first polishing inhibitor suppresses polishing of substances other than the object to be polished. That is, the polishing selectivity is adjusted while suppressing polishing of each substance. Here, the substance other than the object to be polished may include a plurality of different substances having different components. For example, when polishing an oxide, the first polishing inhibitor may adjust the selection ratio by suppressing polishing of the first substance and the second substance contained in the plurality of different substances.
このような第１の研磨抑制剤は、酸化物に比べて第１の物質、例えば、ポリシリコンに対する結合力に優れた物質であり、疎水性基及び親水性基を併せ持つノニオン系物質を用いることができる。このような第１の研磨抑制剤は、疎水性及び親水性を併せ持って、疎水性を有するポリシリコンの膜の表面に吸着してパッシベーション膜を形成し、その結果、ポリシリコンの研磨率を相対的に大幅に下げて研磨選択比を調節することができる。 Such a first polishing inhibitor is a substance that has a superior binding force to a first substance, such as polysilicon, compared to an oxide, and uses a nonionic substance having both a hydrophobic group and a hydrophilic group. Can do. Such a first polishing inhibitor has both hydrophobicity and hydrophilicity and adsorbs to the surface of the hydrophobic polysilicon film to form a passivation film. As a result, the polishing rate of the polysilicon is relatively increased. In particular, the polishing selectivity can be adjusted with a significant reduction.
第１の研磨抑制剤としては、各種のノニオン系物質が使用可能であり、例えば、第１の研磨抑制剤としては、ポリプロピレングリコール−ポリエチレングリコール−ポリプロピレングリコール共重合体（ＰＥＰ：ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ）、ポリソルベート（ｐｏｌｙｓｏｒｂａｔｅｓ）、オクトキシノール（ｏｃｔｏｘｙｎｏｌ）、ポリエチレングリコール（ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ）、オクタデシルエーテル（ｏｃｔａｄｅｃｙｌ ｅｔｈｅｒ）、ノニルフェノールエトキシレート（ｎｏｎｙｌｐｈｅｎｏｌ ｅｔｈｏｘｙｌａｔｅ）、エチレンオキシド（ｅｔｈｙｌｅｎｅ ｏｘｉｄｅ）、グリコール酸（ｇｌｙｃｏｌｉｃ ａｃｉｄ）、グリセロールエトキシレート（ｇｌｙｃｅｒｏｌ ｅｔｈｏｘｙｌａｔｅ）のうちの少なくとも一種が挙げられる。 As the first polishing inhibitor, various nonionic substances can be used. For example, as the first polishing inhibitor, a polypropylene glycol-polyethylene glycol-polypropylene glycol copolymer (PEP: polypropyleneglycol-b-polyethyleneglycol) can be used. -B-polypropylenecol, polysorbates, octoxynol, polyethyleneglycol, octadecylether, nonylphenol ethoxylate (nonethylethylene glycol) ycolic acid), include at least one of glycerol ethoxylate (glycerol ethoxylate).
第１の研磨抑制剤の含量は、第１のスラリーの総質量の約０．００２質量％〜約０．０２質量％であってもよい。第１の研磨抑制剤の含量が０．００２質量％未満であれば、例えば、研磨停止膜として用いられるポリシリコン膜の研磨率が高過ぎ、０．０２質量％を超えると、ポリシリコン膜に過剰に吸着されて酸化膜及びポリシリコン膜の研磨選択比を適正な範囲に維持することができない。なお、第１の研磨抑制剤の含量が０．００５質量％〜０．０１５質量％の範囲である場合、十分な選択比の調節効果を有するとともに、ポリシリコン膜の研磨率を適正なレベルに維持することができる。 The content of the first polishing inhibitor may be from about 0.002% to about 0.02% by weight of the total weight of the first slurry. If the content of the first polishing inhibitor is less than 0.002% by mass, for example, the polishing rate of the polysilicon film used as the polishing stopper film is too high, and if it exceeds 0.02% by mass, Due to excessive adsorption, the polishing selectivity of the oxide film and the polysilicon film cannot be maintained within an appropriate range. In addition, when the content of the first polishing inhibitor is in the range of 0.005% by mass to 0.015% by mass, it has a sufficient selection ratio adjusting effect, and the polishing rate of the polysilicon film is set to an appropriate level. Can be maintained.
研磨促進剤は、第２のスラリーに含まれて研磨対象物質の研磨を促す。すなわち、研磨促進剤により研磨対象物質の研磨を促し、研磨対象以外の物質の研磨を抑えて研磨選択比を調節する。例えば、酸化物を研磨する場合、研磨促進剤は、酸化物の研磨を促し、酸化物以外のポリシリコン及び窒化物の研磨をそれぞれ抑えて選択比を調節してもよい。 The polishing accelerator is contained in the second slurry and promotes polishing of the material to be polished. That is, the polishing accelerator is urged to polish the polishing target substance, and the polishing selectivity is adjusted by suppressing the polishing of the substance other than the polishing target. For example, when polishing an oxide, the polishing accelerator may promote polishing of the oxide, and may control the selection ratio by suppressing polishing of polysilicon and nitride other than the oxide.
このような研磨促進剤としては、ヒドロキシル基（ＯＨ）及びアミン基（ＮＨ２）を併せ持つアルカノールアミン系の単分子物質を用いることができる。このような研磨促進剤は、解離定数の絶対値であるｐＫａ値が約９．７の値を有して、ｐＨ９．７以下の溶液内においてプラスチャージを帯びる正の電荷であるＮＨ３ ＋に解離される。解離されたＮＨ３ ＋は溶液内において負の電荷を帯びる、例えば、酸化膜（ＳｉＯＨ−）と作用して酸化膜がＳｉ（ＯＨ４）の形で反応することを促して酸化膜の研磨率を上げる。 As such a polishing accelerator, an alkanolamine-based monomolecular substance having both a hydroxyl group (OH) and an amine group (NH 2 ) can be used. Such a polishing accelerator has a pKa value, which is an absolute value of the dissociation constant, of about 9.7, and has a positive charge in NH 3 + in a solution having a pH of 9.7 or lower. Dissociated. The dissociated NH 3 + has a negative charge in the solution, for example, acts on the oxide film (SiOH − ) to promote the reaction of the oxide film in the form of Si (OH 4 ), and the polishing rate of the oxide film Raise.
研磨促進剤としては、アルカノールアミン（Ａｌｋａｎｏｌａｍｉｎｅ）系の単分子物質が使用可能であり、例えば、研磨促進剤は、アミノメチルプロパノール（ＡＭＰ：Ａｍｉｎｏｍｅｔｈｙｌ ｐｒｏｐａｎｏｌ）、エタノールアミン（Ｅｔｈａｎｏｌａｍｉｎｅ）、ヘプタミノール（Ｈｅｐｔａｍｉｎｏｌ）、イソエタリン（Ｉｓｏｅｔｈａｒｉｎｅ）、メタノールアミン（Ｍｅｔｈａｎｏｌａｍｉｎｅ）、ジエチルエタノールアミン（Ｄｉｅｔｈｙｌｅｔｈａｎｏｌａｍｉｎｅ）及びＮ−メチルエタノールアミン（Ｎ−ｍｅｔｈｙｌｅｔｈａｎｏｌａｍｉｎｅ）のうちの少なくともいずれか一種を含んでいてもよい。このような単分子物質は、官能基としてヒドロキシル基及びアミン基を有していてもよい。 As the polishing accelerator, alkanolamine-based monomolecular substances can be used. For example, the polishing accelerator includes aminomethylpropanol (AMP), ethanolamine, heptaminol, It may include at least one of isoethaline, methanolamine, diethylethanolamine, and N-methylethanolamine. Such a monomolecular substance may have a hydroxyl group and an amine group as functional groups.
研磨促進剤の含量は、第２のスラリーの総質量の約０．１質量％〜約１．３５質量％であってもよい。研磨促進剤の含量が０．１質量％未満であれば、研磨対象物、例えば、酸化膜の研磨率が低過ぎたり、研磨対象物以外の物質、例えば、窒化膜の研磨率が高過ぎたりして酸化膜及び窒化膜の適正な研磨選択比レベルを満たすことができず、１．３５質量％を超えると、窒化膜の研磨率が急激に下がって研磨効率が低下する虞がある。なお、研磨促進剤の含量が０．５質量％〜１質量％の範囲である場合、酸化膜及び窒化膜の研磨率を最適なレベルに調節することができる。 The content of the polishing accelerator may be from about 0.1% to about 1.35% by weight of the total weight of the second slurry. If the content of the polishing accelerator is less than 0.1% by mass, the polishing rate of the object to be polished, for example, the oxide film is too low, or the substance other than the polishing object, for example, the polishing rate of the nitride film is too high. Therefore, if the appropriate polishing selection ratio level of the oxide film and the nitride film cannot be satisfied, and if it exceeds 1.35% by mass, the polishing rate of the nitride film may be drastically lowered and the polishing efficiency may be lowered. In addition, when the content of the polishing accelerator is in the range of 0.5% by mass to 1% by mass, the polishing rate of the oxide film and the nitride film can be adjusted to an optimum level.
第２の研磨抑制剤は、第２のスラリーに含まれて研磨対象以外の物質の研磨を抑える。すなわち、各物質の研磨を抑えて、研磨選択比を調節する。例えば、酸化物を研磨する場合、第２の研磨抑制剤は、複数の異種物質に含まれる第１の物質及び第２の物質の研磨をそれぞれ抑えて選択比を調節することができる。 The second polishing inhibitor is contained in the second slurry and suppresses polishing of substances other than the object to be polished. That is, the polishing selectivity is adjusted while suppressing polishing of each substance. For example, when polishing an oxide, the second polishing inhibitor can adjust the selection ratio by suppressing polishing of the first substance and the second substance contained in the plurality of different substances.
第２の研磨抑制剤としては、カルボキシル基を一つ以上有するアニオン系物質を用いることができる。このような第２の研磨抑制剤は、解離定数の絶対値であるｐＫａ値が約４の値を有して、ｐＨ４以上の溶液においてマイナスチャージを帯びる負の電荷であるＣＯＯ−に解離される。解離されたＣＯＯ−基は、研磨対象以外の物質、例えば、正の電荷を帯びる窒化物に吸着されてもよい。 As the second polishing inhibitor, an anionic substance having one or more carboxyl groups can be used. Such a second polishing inhibitor has a pKa value of about 4 as an absolute value of the dissociation constant, and is dissociated into COO − which is a negative charge having a negative charge in a solution of pH 4 or higher. . The dissociated COO − group may be adsorbed by a substance other than the object to be polished, for example, a positively charged nitride.
第２の研磨抑制剤は、カルボキシル基を有しているアニオン系物質が使用可能であり、例えば、第２の研磨抑制剤は、ポリアクリル酸（ＰＡＡ：ｐｏｌｙ（ａｃｒｙｌｉｃ ａｃｉｄ））、ポリアルキルメタクリレート（ｐｏｌｙ（ａｌｋｙｌ ｍｅｔｈａｃｒｙｌａｔｅ））、アクリルアミド（ａｃｒｙｌａｍｉｄｅ）、メタクリルアミド（ｍｅｔｈａｃｒｙｌａｍｉｄｅ）及びエチル−メタクリルアミド（ｅｔｈｙｌ−ｍｅｔｈａｃｒｙｌａｍｉｄｅ）のうちの少なくともいずれか一種を含んでいてもよい。各アニオン系物質は、少なくとも一つのカルボキシル基を含んでおり、このようなアニオン系物質は、官能基としてカルボキシル基のみを有していてもよく、カルボキシル基以外に他の官能基をさらに有していてもよい。 As the second polishing inhibitor, an anionic substance having a carboxyl group can be used. For example, the second polishing inhibitor is polyacrylic acid (PAA: poly (acrylic acid)), polyalkyl methacrylate. (Poly (alkyl methacrylate)), acrylamide (acrylamide), methacrylamide (methacrylamide), and ethyl-methacrylamide (ethyl-methacrylamide) may be included. Each anionic substance contains at least one carboxyl group, and such an anionic substance may have only a carboxyl group as a functional group, and further has another functional group in addition to the carboxyl group. It may be.
第２の研磨抑制剤の含量は、第２のスラリーの総質量の約０．１５質量％〜約１質量％であってもよい。研磨促進剤の含量が０．１５質量％未満であれば、窒化物膜に十分に吸着されないため選択比の調節効果が十分に得られず、１質量％を超えると、窒化物膜に過剰に吸着されて窒化物膜の研磨率が過度に下がって酸化物対第２の物質、例えば、窒化物との研磨選択比が目標数値である２０：１〜６０：１の範囲から外れる虞がある。 The content of the second polishing inhibitor may be from about 0.15% to about 1% by weight of the total weight of the second slurry. If the content of the polishing accelerator is less than 0.15% by mass, the nitride film is not sufficiently adsorbed, so that the effect of adjusting the selection ratio is not sufficiently obtained. If the content exceeds 1% by mass, the nitride film is excessively contained. There is a possibility that the polishing rate of the nitride film is excessively decreased due to adsorption and the polishing selectivity ratio of the oxide to the second substance, for example, nitride, is out of the target range of 20: 1 to 60: 1. .
第１のｐＨ調節剤及び第２のｐＨ調節剤は、第１のスラリー及び第２のスラリーにそれぞれ含まれて各スラリーのｐＨを調節することができる。このようなｐＨ調節剤として、硝酸、アンモニア水などを含んでいてもよい。本発明の実施形態においては、ｐＨ調節剤を用いて第１のスラリー及び第２のスラリーのｐＨを４〜８の範囲に同様に調節することができる。ｐＨが４未満である場合、スラリーの分散安定性が悪化され、ｐＨが８を超える場合、強塩基性により研磨対象以外の物質、例えば、研磨停止膜として用いられるポリシリコン膜の研磨率が急激に上昇する虞がある。なお、第１のスラリー及び第２のスラリーのｐＨは、６〜７の範囲に調節されるが、この場合、分散安定性を維持するとともに、研磨対象物質及び研磨対象以外の物質の研磨選択比を最適に維持することができるためである。 The first pH adjusting agent and the second pH adjusting agent can be included in the first slurry and the second slurry, respectively, to adjust the pH of each slurry. As such a pH regulator, nitric acid, aqueous ammonia, or the like may be included. In the embodiment of the present invention, the pH of the first slurry and the second slurry can be similarly adjusted to a range of 4 to 8 using a pH adjuster. When the pH is less than 4, the dispersion stability of the slurry is deteriorated, and when the pH exceeds 8, the polishing rate of a substance other than the object to be polished, for example, a polysilicon film used as a polishing stopper film is rapidly increased due to strong basicity. There is a risk of rising. The pH of the first slurry and the second slurry is adjusted in the range of 6 to 7. In this case, while maintaining the dispersion stability, the polishing selectivity of the material to be polished and the material other than the object to be polished This is because it can be maintained optimally.
また、第１のスラリー及び第２のスラリーは、１：０．５〜１：１．５の割合で混合されてもよく、このとき、第１のスラリー及び希釈剤は、１：３〜１：８の割合で混合されてもよい。第１のスラリー及び第２のスラリーを１：０．５〜１：１．５の割合で混合し、第１のスラリー及び希釈剤を１：３〜１：８の割合で混合して酸化物スラリーを製造する場合、酸化物に対する研磨率を２０００Å／ｍｉｎ以上、さらに２５００Å／ｍｉｎ以上に維持することができ、窒化物に対する研磨率を５０〜１５０Å／ｍｉｎ、好ましくは、５０〜１００Å／ｍｉｎの範囲に維持することができる。さらに、このとき、ポリシリコンの研磨率は、５０Å／ｍｉｎ以下、さらに２０Å／ｍｉｎ以下に維持されて、酸化物対第１の物質、例えば、ポリシリコンの研磨選択比を１００：１〜３００：１の範囲に維持し、酸化物対第２の物質、例えば、窒化物の研磨選択比を２０：１〜６０：１の範囲に維持することができる。 In addition, the first slurry and the second slurry may be mixed at a ratio of 1: 0.5 to 1: 1.5. At this time, the first slurry and the diluent are in the range of 1: 3 to 1. : You may mix in the ratio of 8. The first slurry and the second slurry are mixed in a ratio of 1: 0.5 to 1: 1.5, and the first slurry and the diluent are mixed in a ratio of 1: 3 to 1: 8. In the case of producing a slurry, the polishing rate for oxides can be maintained at 2000 kg / min or more, further 2500 kg / min or more, and the polishing rate for nitride is 50 to 150 kg / min, preferably 50 to 100 kg / min. Can be kept in range. Further, at this time, the polishing rate of polysilicon is maintained at 50 Å / min or less, and further 20 Å / min or less, and the polishing selection ratio of the oxide to the first material, for example, polysilicon is 100: 1 to 300: The polishing selectivity ratio of the oxide to the second material, eg, nitride, can be maintained in the range of 20: 1 to 60: 1.
以下、前記実施形態のスラリーを製造し、半導体基板に適用して研磨特性を評価した結果について説明する。 Hereinafter, the result of manufacturing the slurry of the embodiment and applying it to a semiconductor substrate to evaluate the polishing characteristics will be described.
スラリーの製造過程は、通常のスラリーの製造過程と略同じであるため、これについて簡略に説明する。 Since the manufacturing process of the slurry is substantially the same as the manufacturing process of a normal slurry, this will be briefly described.
まず、第１のスラリーを製造するためには、第１のスラリーを製造する容器を用意し、容器に所望の量の超純水と、アニオン系分散剤及び分散安定剤としての有機酸を入れて十分に混合し、多面体結晶面を有し、且つ、所定の研磨粒子の平均粒径を有する湿式セリア粒子を研磨剤として所定量測量して投入して均一に混合した。また、第１の研磨抑制剤としてポリプロピレングリコール−ポリエチレングリコール−ポリプロピレングリコール共重合体（ＰＥＰ：ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ）を容器に所定量投入した後に均一に混合した。次いで、硝酸などのｐＨ調節剤を容器に投入して第１のスラリーのｐＨを調節した。 First, in order to produce the first slurry, a container for producing the first slurry is prepared, and a desired amount of ultrapure water and an anionic dispersant and an organic acid as a dispersion stabilizer are placed in the container. The wet ceria particles having a polyhedral crystal face and having an average particle diameter of predetermined abrasive particles were weighed in a predetermined amount as an abrasive and mixed uniformly. In addition, a predetermined amount of polypropylene glycol-polyethylene glycol-polypropylene glycol copolymer (PEP) was added to the container as a first polishing inhibitor, and then uniformly mixed. Next, a pH adjusting agent such as nitric acid was added to the container to adjust the pH of the first slurry.
さらに、第２のスラリーを製造するためには、第２のスラリーを製造する容器を用意し、容器に所望の量の超純水と、研磨促進剤及び第２の研磨抑制剤を所定量測量して投入して均一に混合した。ここで、研磨促進剤としてはアミノメチルプロパノール（ＡＭＰ：Ａｍｉｎｏｍｅｔｈｙｌ ｐｒｏｐａｎｏｌ）を用い、第２の研磨抑制剤としてはポリアクリル酸（ＰＡＡ：ｐｏｌｙａｃｒｙｌｉｃ ａｃｉｄ）を用いた。次いで、硝酸などのｐＨ調節剤を容器に投入して第２のスラリーのｐＨを調節した。 Furthermore, in order to manufacture the second slurry, a container for manufacturing the second slurry is prepared, and a predetermined amount of ultrapure water, a polishing accelerator, and a second polishing inhibitor are measured in a predetermined amount in the container. And then uniformly mixed. Here, aminomethyl propanol (AMP) was used as the polishing accelerator, and polyacrylic acid (PAA) was used as the second polishing inhibitor. Next, a pH adjusting agent such as nitric acid was added to the container to adjust the pH of the second slurry.
次いで、容器に希釈剤としての所望の量の超純水と、第１のスラリー及び第２のスラリーを混合して酸化物スラリーを製造した。これらの各物質の投入及び混合順序は、特に限定されない。 Next, an oxide slurry was produced by mixing a desired amount of ultrapure water as a diluent, the first slurry, and the second slurry in a container. The order of adding and mixing these substances is not particularly limited.
本実験例において酸化セリウム、すなわち、セリア粒子は、第１のスラリーの総質量に対して、５質量％含有されるように投入し、分散剤及び分散安定剤は、第１のスラリーの総質量に対して、それぞれ０．１５質量％及び０．０２質量％含有されるように投入した。また、第１の研磨抑制剤は、第１のスラリーの総質量に対して、０質量％から０．０２質量％まで様々な量で含まれるように投入し、研磨促進剤及び第２の研磨抑制剤は、第２のスラリーの総質量に対して、それぞれ０質量％から１．３５質量％まで、及び０質量％から０．３質量％まで様々な量で含まれるように投入した。 In this experimental example, cerium oxide, that is, ceria particles are added so as to be contained by 5 mass% with respect to the total mass of the first slurry, and the dispersant and the dispersion stabilizer are the total mass of the first slurry. The content was 0.15% by mass and 0.02% by mass, respectively. The first polishing inhibitor is added so as to be included in various amounts from 0% by mass to 0.02% by mass with respect to the total mass of the first slurry, and the polishing accelerator and the second polishing agent are added. The inhibitor was added so as to be included in various amounts from 0% by mass to 1.35% by mass and from 0% by mass to 0.3% by mass, respectively, with respect to the total mass of the second slurry.
すなわち、第１のスラリー及び第２のスラリーに含有される第１の研磨抑制剤、研磨促進剤及び第２の研磨抑制剤の投入量に応じて複数の第１のスラリー及び第２のスラリーを用意した。第１のスラリー及び第２のスラリーは、硝酸を用いてそれぞれのｐＨが６．５になるようにした。前記成分に加えて、残りの成分としては、不可避的に入れられた不純物及び純水が挙げられ、このようにして製造された第１のスラリー及び第２のスラリーは超純水に混合し、第１のスラリー、第２のスラリー及び超純水を０．７：０．８：３．５の割合で混合して酸化物スラリーを製造した。 That is, a plurality of first slurries and second slurries are added according to the input amounts of the first polishing inhibitor, the polishing accelerator, and the second polishing inhibitor contained in the first slurry and the second slurry. Prepared. The first slurry and the second slurry were each adjusted to pH 6.5 using nitric acid. In addition to the above components, the remaining components include unavoidably introduced impurities and pure water. The first slurry and the second slurry thus produced are mixed with ultrapure water, The first slurry, the second slurry, and ultrapure water were mixed at a ratio of 0.7: 0.8: 3.5 to produce an oxide slurry.
図１は、本発明の実施形態において第１の研磨抑制剤を様々な量で含まれるように投入したスラリーの研磨結果を示す図であり、図２は、第１の研磨抑制剤の濃度による酸化物の研磨率を示すグラフ図である。また、図３は、本発明の実施形態において研磨促進剤を様々な量で含まれるように投入したスラリーの研磨結果を示す図であり、図４は、研磨促進剤の濃度による酸化物の研磨率を示すグラフ図である。図５は、本発明の実施形態において第２の研磨抑制剤を様々な量で含まれるように投入したスラリーの研磨結果を示す図であり、図６は、第２の研磨抑制剤の濃度による酸化物の研磨率を示すグラフ図である。ここで、シリコン酸化物、シリコン窒化物及びポリシリコンの研磨率は、シリコン酸化膜ウェーハ、シリコン窒化膜ウェーハ及びポリシリコン膜ウェーハをそれぞれ研磨して算出したものであり、研磨選択比は、シリコン酸化膜の研磨率とシリコン窒化膜またはポリシリコン膜の研磨率との間の割合である。すなわち、シリコン酸化膜の研磨率をシリコン窒化膜またはポリシリコン膜の研磨率で割った値である。 FIG. 1 is a diagram showing the polishing results of a slurry charged so as to contain various amounts of the first polishing inhibitor in the embodiment of the present invention, and FIG. 2 shows the concentration of the first polishing inhibitor. It is a graph which shows the polishing rate of an oxide. FIG. 3 is a diagram showing the results of polishing the slurry charged so as to contain various amounts of the polishing accelerator in the embodiment of the present invention, and FIG. 4 shows the polishing of the oxide according to the concentration of the polishing accelerator. It is a graph which shows a rate. FIG. 5 is a diagram showing the polishing results of the slurry charged so as to contain various amounts of the second polishing inhibitor in the embodiment of the present invention, and FIG. 6 shows the concentration of the second polishing inhibitor. It is a graph which shows the polishing rate of an oxide. Here, the polishing rates of silicon oxide, silicon nitride, and polysilicon are calculated by polishing a silicon oxide film wafer, a silicon nitride film wafer, and a polysilicon film wafer, respectively. It is a ratio between the polishing rate of the film and the polishing rate of the silicon nitride film or the polysilicon film. That is, it is a value obtained by dividing the polishing rate of the silicon oxide film by the polishing rate of the silicon nitride film or the polysilicon film.
図１および図２から明らかなように、第１の研磨抑制剤の量が増えると、シリコン酸化物と、シリコン窒化物及びポリシリコンの研磨率がいずれも全体的に下がった。また、シリコン酸化物の研磨速度はシリコン窒化物の研磨速度よりも速く、シリコン窒化物の研磨速度はポリシリコンの研磨速度よりも全体的に速く調節されることが分かる。第１の研磨抑制剤は、ポリシリコンの研磨率を大幅に下げ、これに関する原理については既に説明した。 As apparent from FIGS. 1 and 2, as the amount of the first polishing inhibitor increases, the polishing rates of silicon oxide, silicon nitride, and polysilicon all decrease as a whole. Also, it can be seen that the polishing rate of silicon oxide is faster than the polishing rate of silicon nitride, and the polishing rate of silicon nitride is adjusted to be faster overall than the polishing rate of polysilicon. The first polishing inhibitor significantly reduces the polishing rate of polysilicon, and the principle relating to this has already been described.
第１のスラリーに含まれる第１の研磨抑制剤の含量が０．００２質量％であり、第２のスラリーに含まれる研磨促進剤及び第２の研磨抑制剤の含量がそれぞれ０．９質量％及び０．２質量％である場合、シリコン酸化物及びポリシリコンの研磨選択比は約２３６であり、第１の研磨抑制剤の含量が０質量％である場合の研磨選択比である４６に比べて非常に高い値を示した。 The content of the first polishing inhibitor contained in the first slurry is 0.002% by mass, and the content of the polishing accelerator and the second polishing inhibitor contained in the second slurry is 0.9% by mass, respectively. And 0.2 mass%, the polishing selectivity ratio of silicon oxide and polysilicon is about 236, compared with 46, which is the polishing selectivity ratio when the content of the first polishing inhibitor is 0 mass%. Very high value.
また、図３及び図４から明らかなように、研磨促進剤の量が増えると、シリコン窒化物及びポリシリコンの研磨率はやや下がるが、シリコン酸化物の研磨率は大幅に上がった。これに関する原理については既に説明した。また、第１のスラリーに含まれる第１の研磨抑制剤の含量が０．０１質量％であり、第２のスラリーに含まれる研磨促進剤及び第２の研磨抑制剤の含量がそれぞれ０．１質量％及び０．２質量％である場合、シリコン酸化物及びシリコン窒化物の研磨選択比は２５であり、シリコン酸化物及びポリシリコンの研磨選択比は１５３であって、研磨促進剤の含量が０質量％である場合のシリコン酸化物及びシリコン窒化物の研磨選択比である１３及びシリコン酸化物及びポリシリコンの研磨選択比である９２に比べて非常に高い値を示した。 Further, as apparent from FIGS. 3 and 4, when the amount of the polishing accelerator is increased, the polishing rate of silicon nitride and polysilicon is slightly lowered, but the polishing rate of silicon oxide is significantly increased. The principle of this has already been explained. Further, the content of the first polishing inhibitor contained in the first slurry is 0.01% by mass, and the contents of the polishing accelerator and the second polishing inhibitor contained in the second slurry are each 0.1%. In the case of mass% and 0.2 mass%, the polishing selectivity of silicon oxide and silicon nitride is 25, the polishing selectivity of silicon oxide and polysilicon is 153, and the content of the polishing accelerator is When the content was 0% by mass, the polishing selectivity of silicon oxide and silicon nitride was 13 and the polishing selectivity of silicon oxide and polysilicon was 92, which was a very high value.
これらに加えて、図５及び図６から明らかなように、第２の研磨抑制剤の量が増えると、シリコン酸化物の研磨率と、シリコン窒化物及びポリシリコンの研磨率がいずれも全体的に下がった。第２の研磨抑制剤は、シリコン酸化物及びシリコン窒化物の研磨率を大幅に下げ、これらのうち、シリコン窒化物の研磨率の減少率が大きいことが分かる。これに関する原理については既に説明した。 In addition to these, as is apparent from FIGS. 5 and 6, when the amount of the second polishing inhibitor increases, the polishing rate of silicon oxide and the polishing rates of silicon nitride and polysilicon are both overall. Went down. It can be seen that the second polishing inhibitor significantly reduces the polishing rate of silicon oxide and silicon nitride, and of these, the reduction rate of the polishing rate of silicon nitride is large. The principle of this has already been explained.
すなわち、第１のスラリーに含まれる第１の研磨抑制剤の含量が０．０１質量％であり、第２のスラリーに含まれる研磨促進剤及び第２の研磨抑制剤の含量がそれぞれ０．９質量％及び０．１５質量％である場合、シリコン酸化物及びシリコン窒化物の研磨選択比は約３０であり、第２の研磨抑制剤の含量が０質量％である場合の研磨選択比である５に比べて非常に高い値を示した。 That is, the content of the first polishing inhibitor contained in the first slurry is 0.01% by mass, and the contents of the polishing accelerator and the second polishing inhibitor contained in the second slurry are each 0.9. In the case of mass% and 0.15 mass%, the polishing selectivity ratio of silicon oxide and silicon nitride is about 30, and the polishing selectivity ratio when the content of the second polishing inhibitor is 0 mass%. Compared to 5, the value was very high.
図７は、別途の実験により第１の研磨抑制剤の種類による酸化物の研磨率を比較するためのグラフであり、図８は、第１の研磨抑制剤の種類による酸化物の研磨結果を示す表である。 FIG. 7 is a graph for comparing the polishing rate of the oxide according to the type of the first polishing inhibitor by a separate experiment, and FIG. 8 shows the polishing result of the oxide according to the type of the first polishing inhibitor. It is a table | surface which shows.
図７及び図８から明らかなように、第１の研磨抑制剤として、ポリシリコンに対する結合力に優れた物質である、疎水性基及び親水性基を併せ持つノニオン系物質であるポリプロピレングリコール−ポリエチレングリコール−ポリプロピレングリコール共重合体（ＰＥＰ：ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ−ｂ−ｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌ）（以下、ＰＥＰと称する。）を用いる場合、従来のポリシリコンの研磨抑制剤として用いるポリビニルピロリドン（ＰＶＰ：ｐｏｌｙ ｖｉｎｙｌ ｐｙｒｒｏｌｉｄｏｎｅ）（以下、ＰＶＰと称する。）に比べて、シリコン酸化物の研磨率の減少幅が−９．４から−６．７へとさらに小さくなるだけではなく、ポリシリコンの研磨率はむしろさらに大幅に下がることが分かる。 As is apparent from FIGS. 7 and 8, as the first polishing inhibitor, a polypropylene glycol-polyethylene glycol, which is a nonionic substance having both a hydrophobic group and a hydrophilic group, which is a substance excellent in bonding force to polysilicon. -When using a polypropylene glycol copolymer (PEP: polypropyleneglycol-b-polypropyleneglycol) (hereinafter referred to as PEP), polyvinyl pyrrolidone (PVP) used as a conventional polysilicon polishing inhibitor (Hereinafter referred to as “PVP”), the reduction rate of the polishing rate of silicon oxide is not only further reduced from −9.4 to −6.7, but also polishing of polysilicon. It can be seen that the fall in the further significantly rather.
第１の研磨抑制剤としてＰＥＰを用いる場合、従来のＰＶＰを用いる場合に比べてシリコン酸化物の研磨率の減少幅が小さくなる理由は、図９及び図１０から推察可能である。すなわち、図９は、セリア粒子にＰＶＰ及びＰＥＰをそれぞれ添加した場合におけるセリア粒子の表面電位、すなわち、ゼータ電位値を示す表であり、図１０は、前記ゼータ電位の変化を比較するためのグラフである。 When PEP is used as the first polishing inhibitor, the reason why the reduction rate of the polishing rate of silicon oxide is smaller than when using conventional PVP can be inferred from FIGS. 9 and 10. That is, FIG. 9 is a table showing the surface potential of ceria particles, that is, zeta potential values when PVP and PEP are added to the ceria particles, respectively, and FIG. 10 is a graph for comparing changes in the zeta potential. It is.
図９及び図１０から明らかなように、スラリー内のセリア粒子の表面電位は−４５〜−５０ｍＶの範囲の値を有し、ノニオン性であるＰＥＰまたはＰＶＰをスラリー内に添加する場合にセリア粒子の表面電位は上がる。ここで、濃度による表面電位の増加率を見ると、ＰＶＰの場合に約１２７の勾配値を有して、２８の勾配値を有するＰＥＰに比べて表面電位の増加率が大きい。このため、酸化物の研磨に際して酸化物の表面電位は−５０〜−６０ｍＶの範囲の値を有するので、ＰＶＰの場合にＰＥＰに比べて酸化物との静電気力、すなわち、静電気的な斥力が弱く作用して酸化物に吸着され易い。このため、上述した如き静電気力差によりＰＥＰのシリコン酸化物の研磨率の減少幅がＰＶＰに比べて小さくなる。 As is apparent from FIGS. 9 and 10, the surface potential of the ceria particles in the slurry has a value in the range of −45 to −50 mV, and the ceria particles are added when non-ionic PEP or PVP is added to the slurry. The surface potential increases. Here, looking at the increase rate of the surface potential depending on the concentration, the PVP has a gradient value of about 127, and the increase rate of the surface potential is larger than that of the PEP having 28 gradient values. For this reason, since the surface potential of the oxide has a value in the range of −50 to −60 mV when polishing the oxide, the electrostatic force with the oxide, that is, the electrostatic repulsive force, is weaker than that of PEP in the case of PVP. It acts and is easily adsorbed by the oxide. For this reason, the amount of decrease in the polishing rate of the silicon oxide of PEP is smaller than that of PVP due to the difference in electrostatic force as described above.
また、第１の研磨抑制剤としてのＰＥＰを０．００５質量％で含有する場合のシリコン酸化物対ポリシリコンの研磨選択比は１６０であり、同じ量のＰＶＰを含有する場合のシリコン酸化物対ポリシリコンの研磨選択比である１１に比べてはるかに高い研磨選択比を有することが分かる。
In addition, when the PEP as the first polishing inhibitor is contained at 0.005 mass%, the polishing selection ratio of silicon oxide to polysilicon is 160, and the silicon oxide pair when the same amount of PVP is contained. It can be seen that the polishing selectivity is much higher than the polishing
このため、従来のポリシリコンの研磨抑制剤として用いられていたＰＶＰは、シリコン酸化物の研磨率を急激に下げて最適な研磨選択比の範囲を検出し難いのに対し、本発明の実施形態によるＰＥＰを第１の研磨抑制剤として用いる場合には、シリコン酸化物の研磨率を緩やかに下げてシリコン酸化膜の研磨率パターンだけではなく、シリコン酸化物対ポリシリコンの研磨選択比を向上させて高選択比を有するように調節することが可能になる。 For this reason, PVP used as a conventional polysilicon polishing inhibitor is difficult to detect the range of the optimum polishing selectivity by rapidly reducing the polishing rate of silicon oxide, whereas the embodiment of the present invention When the PEP is used as the first polishing inhibitor, the polishing rate of the silicon oxide is gradually lowered to improve not only the polishing rate pattern of the silicon oxide film but also the polishing selectivity ratio of silicon oxide to polysilicon. Can be adjusted to have a high selectivity.
本発明の実施形態によるスラリーは、半導体素子の製造工程における酸化物の研磨工程に使用可能である。例えば、フラッシュメモリ素子の製造過程において素子分離膜を形成するためにポリシリコン膜を研磨停止膜として用い、ポリシリコン膜の上にシリコン窒化膜をハードマスクとして用いてパターンを形成することができる。このため、このようなパターンが形成された複数の異種物質層の上にシリコン酸化膜を形成する場合、研磨すべきパターン及び研磨停止膜の種類に応じて適切な研磨選択比を有するスラリーを選択して研磨工程を行うことができる。すなわち、シリコン酸化膜に対して高い研磨率を有するだけではなく、シリコン窒化膜に対して研磨速度を下げ、ポリシリコン膜において研磨を停止するために、シリコン窒化膜の研磨率をポリシリコン膜の研磨率よりも所定のレベルだけ高く維持する最適範囲の研磨選択比を有するスラリーを半導体素子の製造工程に用いることができる。このような本発明のスラリーを用いた半導体素子の製造方法について図１１を用いて説明すると、下記の通りである。以下の説明においては、上述したスラリーに関して既に説明した内容と重複する説明は省略する。 The slurry according to the embodiment of the present invention can be used in an oxide polishing process in a semiconductor element manufacturing process. For example, a pattern can be formed using a polysilicon film as a polishing stopper film and forming a silicon nitride film as a hard mask on the polysilicon film in order to form an element isolation film in the manufacturing process of the flash memory device. For this reason, when a silicon oxide film is formed on a plurality of different material layers having such a pattern, a slurry having an appropriate polishing selection ratio is selected according to the pattern to be polished and the type of polishing stopper film. Thus, a polishing process can be performed. That is, not only has a high polishing rate for the silicon oxide film, but also reduces the polishing rate for the silicon nitride film and stops the polishing in the polysilicon film so that the polishing rate of the silicon nitride film is reduced. A slurry having a polishing selection ratio in an optimum range that is maintained at a predetermined level higher than the polishing rate can be used in the semiconductor element manufacturing process. A method for manufacturing a semiconductor device using the slurry of the present invention will be described with reference to FIG. In the following description, the description which overlaps the content already demonstrated regarding the slurry mentioned above is abbreviate | omitted.
図１１は、本発明の一実施形態による半導体素子の製造方法を説明するための断面図である。図１１（ａ）を参照すると、基板１１０の上に第１の物質層１２０及び第２の物質層１３０を形成する。ここで、基板１１０としては、半導体素子の製造に用いられる様々な基板を用いることができるが、シリコン基板を用いることができる。基板１１０の上には第１の物質層１２０及び第２の物質層１３０が形成されるが、第１の物質層１２０は、研磨停止膜として用いられる、例えば、ポリシリコン系の物質を用いて形成してもよく、第２の物質層１３０は、パターンの形成のためのマスク層として用いられる、例えば、シリコン窒化物系の物質を用いて形成してもよい。また、第１の物質層１２０及び第２の物質層１３０は、物理蒸着（ＰＶＤ：Ｐｈｙｓｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）方法、化学気相蒸着（ＣＶＤ：Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）方法、金属有機化学蒸着（ＭＯＣＶＤ：Ｍｅｔａｌ Ｏｒｇａｎｉｃ ＣＶＤ）方法、原子層蒸着（ＡＬＤ：Ａｔｏｍｉｃ Ｌａｙｅｒ Ｄｅｐｏｓｉｔｉｏｎ）方法またはＣＶＤ方法及びＡＬＤ方法を併用したＡＬ−ＣＶＤ方法を用いて形成してもよい。
FIG. 11 is a cross-sectional view for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention. Referring to FIG. 11A, the
図１１（ｂ）を参照すると、前記基板１１０の上に第１の物質層１２０を形成した後、第１の物質層１２０の上に第２の物質層１３０をマスクとして用いて基板を所定の深さでエッチングしてパターン１１５を形成する。パターン１１５は、素子分離膜を形成するためのライン状のトレンチであってもよい。
Referring to FIG. 11B, after the
また、図１１（ｃ）に示すように、パターン１１５を有する第２の物質層１３０の全面の上にパターン１１５が埋め込まれるように酸化物層１４０を形成する。
In addition, as illustrated in FIG. 11C, the
図１１（ｄ）を参照すると、酸化物層１４０に対して高い研磨率を有するだけではなく、第２の物質層１３０に対して研磨速度を下げ、第１の物質層１２０において研磨を停止するために、第２の物質層１３０の研磨率を第１の物質層１２０の研磨率よりも所定のレベルだけ高く維持する最適範囲の研磨選択比を有するスラリーを用いて酸化物層１４０及び第２の物質層１３０を研磨する。第２の物質層１３０は、素子の特性の向上のために酸化物層１４０の研磨とともに除去される必要があり、スラリーは、酸化物層１４０対第１の物質層１２０の研磨選択比を１００：１〜３００：１の範囲に維持し、酸化物層１４０対第２の物質層１３０の研磨選択比を２０：１〜６０：１の範囲に維持する。
Referring to FIG. 11D, not only has a high polishing rate with respect to the
研磨過程は、ｐＨ４〜８の領域において行われ、セリア研磨粒子により酸化物層１４０を研磨する過程、研磨促進剤のアミン基が解離されてＮＨ３ ＋基が生成される過程、第２の研磨抑制剤のカルボキシル基が解離されてＣＯＯ−基が生成される過程及び第１の研磨抑制剤の疎水性基が吸着してパッシベーション膜を形成する過程を含む。生成されたＮＨ３ ＋基は、上述したように、溶液内において負の電荷を帯びるシリコン酸化膜（ＳｉＯＨ−）と作用して酸化膜の研磨を促し、生成されたＣＯＯ−基は、シリコン窒化膜の研磨を抑える。また、第１の研磨抑制剤の疎水性基は、ポリシリコンの膜の表面に吸着してパッシベーション膜を形成してポリシリコンの研磨率を抑え、シリコン酸化膜の研磨率を緩やかに減少させてシリコン酸化膜の研磨率を調節し易いだけではなく、シリコン酸化物対ポリシリコンの研磨選択比を向上させて高選択比を有するように調節することができる。
The polishing process is performed in a pH range of 4 to 8, the process of polishing the
以上、本発明の好適な実施形態について特定の用語を用いて説明及び図示したが、このような用語は単に本発明を明確に説明するためのものに過ぎず、本発明の実施形態及び記述された用語は、下記の請求範囲の技術的思想及び範囲から逸脱することなく様々な変更及び変化が加えられてもよいということはいうまでもない。このように変形された実施形態は、本発明の思想及び範囲から個別的に理解されてはならず、本発明の請求範囲内に属するものと理解すべきである。 Although the preferred embodiments of the present invention have been described and illustrated using specific terms, such terms are merely for clear explanation of the present invention and are not limited to the embodiments and description of the present invention. Needless to say, various changes and modifications may be made to the terms without departing from the spirit and scope of the following claims. Such modified embodiments should not be individually understood from the spirit and scope of the present invention, but should be understood to fall within the scope of the claims of the present invention.
１１０ 基板
１２０ 第１の物質層
１３０ 第２の物質層
１４０ 酸化物層
110 substrates
120
Claims (21)
研磨を行う研磨剤と、前記研磨剤を分散させる分散剤及び前記酸化物とは異なる第１の物質の研磨を抑える第１の研磨抑制剤を含む第１のスラリーと、
前記酸化物の研磨を促す研磨促進剤を含む第２のスラリーと、
を含むスラリー。 An oxide polishing slurry comprising:
A first slurry containing a polishing agent for polishing, a dispersant for dispersing the polishing agent, and a first polishing inhibitor for suppressing polishing of a first substance different from the oxide;
A second slurry comprising a polishing accelerator that facilitates polishing of the oxide;
Containing slurry.
酸化物層及び酸化物以外の複数の異種物質により形成される異種物質層が形成された基板を設ける過程と、
研磨剤と、前記研磨剤を分散させる分散剤及び前記複数の異種物質のうち第１の物質の研磨を抑える第１の研磨抑制剤を含む第１のスラリーを設ける過程と、
前記酸化物の研磨を促す研磨促進剤及び前記複数の異種物質のうち第２の物質の研磨を抑える第２の研磨抑制剤を含む第２のスラリーを設ける過程と、
前記第１のスラリー及び第２のスラリーを前記基板の上に供給しながら前記酸化物層を研磨する過程と、
を含む基板の研磨方法。 A method for polishing a substrate,
Providing a substrate on which an oxide layer and a different material layer formed of a plurality of different materials other than oxide are formed;
Providing a first slurry containing an abrasive, a dispersant that disperses the abrasive, and a first polishing inhibitor that suppresses polishing of the first substance among the plurality of different substances;
Providing a second slurry containing a polishing accelerator that promotes polishing of the oxide and a second polishing inhibitor that suppresses polishing of a second substance among the plurality of different substances;
Polishing the oxide layer while supplying the first slurry and the second slurry onto the substrate;
A method for polishing a substrate comprising:
前記基板の上に前記第１の物質により形成される第１の物質層を形成する過程と、
前記第１の物質層の上に前記第２の物質により形成される第２の物質層を形成する過程と、
前記第１の物質層及び第２の物質層にトレンチを形成する過程と、
前記トレンチを有する全面の上に酸化物層を形成する過程と、
を含む請求項１７に記載の基板の研磨方法。 The process of providing the substrate includes
Forming a first material layer formed of the first material on the substrate;
Forming a second material layer formed of the second material on the first material layer;
Forming a trench in the first material layer and the second material layer;
Forming an oxide layer on the entire surface having the trench;
The method for polishing a substrate according to claim 17, comprising:
前記第１のスラリー及び第２のスラリーを１：０．５〜１：１．５の割合で混合して前記基板の上に供給する請求項１７または１８に記載の基板の研磨方法。 The polishing process includes
The method for polishing a substrate according to claim 17 or 18, wherein the first slurry and the second slurry are mixed at a ratio of 1: 0.5 to 1: 1.5 and supplied onto the substrate.
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| US10584266B2 (en) * | 2018-03-14 | 2020-03-10 | Cabot Microelectronics Corporation | CMP compositions containing polymer complexes and agents for STI applications |
| KR102665321B1 (en) * | 2018-03-20 | 2024-05-14 | 삼성디스플레이 주식회사 | Polishing slurry and substrate polishing method using the same |
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| KR102638622B1 (en) * | 2021-07-22 | 2024-02-19 | 에스케이엔펄스 주식회사 | Polishing compostion for semiconductor process and method for manufacturing semiconductor device by using the same |
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