JP2007129247A - Abrasive and slurry - Google Patents
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- JP2007129247A JP2007129247A JP2006335086A JP2006335086A JP2007129247A JP 2007129247 A JP2007129247 A JP 2007129247A JP 2006335086 A JP2006335086 A JP 2006335086A JP 2006335086 A JP2006335086 A JP 2006335086A JP 2007129247 A JP2007129247 A JP 2007129247A
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本発明は、研磨剤、基板の研磨法及び半導体装置の製造法に関する。 The present invention relates to an abrasive, a method for polishing a substrate, and a method for manufacturing a semiconductor device.
従来、半導体装置の製造工程において、プラズマ−ＣＶＤ（化学蒸着）、低圧−ＣＶＤ等の方法で形成されるＳｉＯ２絶縁膜等の無機絶縁膜層を平坦化するための化学機械研磨剤として、コロイダルシリカ系の研磨剤が一般的に検討されている。コロイダルシリカ系の研磨剤は、四塩化珪酸を熱分解する等の方法でシリカ粒子を粒成長させ、アンモニア等のアルカリ金属を含まないアルカリ溶液でｐＨ調整を行って製造している。しかしながら、このような研磨剤は無機絶縁膜の研磨速度が充分な速度を持たず、実用化には低研磨速度という技術課題がある。 Conventionally, colloidal as a chemical mechanical polishing agent for planarizing an inorganic insulating film layer such as a SiO 2 insulating film formed by a method such as plasma-CVD (chemical vapor deposition) or low-pressure CVD in a manufacturing process of a semiconductor device. Silica-based abrasives are generally studied. Colloidal silica-based abrasives are produced by growing silica particles by a method such as thermal decomposition of tetrachlorosilicic acid and adjusting the pH with an alkaline solution not containing an alkali metal such as ammonia. However, such an abrasive does not have a sufficient polishing rate for the inorganic insulating film, and there is a technical problem of low polishing rate for practical use.
一方、フォトマスク用ガラス表面研磨として、酸化セリウム研磨剤が用いられている。酸化セリウム粒子はシリカ粒子やアルミナ粒子に比べ硬度が低く、したがって研磨表面に傷が入りにくいことから仕上げ鏡面研磨に有用である。また、酸化セリウムは強い酸化剤として知られるように、化学的活性な性質を有している。この利点を活かし、絶縁膜用化学機械研磨剤への適用が有用である。しかしながら、フォトマスク用ガラス表面研磨用酸化セリウム研磨剤をそのまま無機絶縁膜研磨に適用すると、１次粒子径が大きく、そのため絶縁膜表面に目視で観察できる研磨傷が入ってしまう。 On the other hand, a cerium oxide abrasive is used for photomask glass surface polishing. Cerium oxide particles have a lower hardness than silica particles and alumina particles, and are therefore useful for finishing mirror polishing because they do not easily scratch the polished surface. Moreover, cerium oxide has a chemically active property as known as a strong oxidant. Taking advantage of this advantage, application to a chemical mechanical polishing agent for insulating films is useful. However, when the cerium oxide abrasive for polishing a glass surface for a photomask is applied as it is to the polishing of an inorganic insulating film, the primary particle size is large, so that a polishing flaw that can be visually observed enters the insulating film surface.
本発明は、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することが可能な研磨剤、基板の研磨法及び半導体装置の製造法を提供するものである。 The present invention provides an abrasive capable of polishing a surface to be polished such as a SiO 2 insulating film at high speed without damage, a method for polishing a substrate, and a method for manufacturing a semiconductor device.
本発明により、２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を、媒体に分散させたスラリーを含む研磨剤が提供される。 The present invention provides an abrasive containing a slurry in which cerium oxide particles composed of two or more crystallites and having crystal grain boundaries are dispersed in a medium.
結晶粒界を有する酸化セリウム粒子径の中央値は、６０〜１５００ｎｍが好ましく、１００〜１２００ｎｍがより好ましく、３００〜１０００ｎｍが最も好ましい。結晶子径の中央値は、５〜２５０ｎｍが好ましく、５〜１５０ｎｍがより好ましい。結晶粒界を有する酸化セリウム粒子径の中央値が３００〜１０００ｎｍであり、結晶子径の中央値が１０〜５０ｎｍである粒子が好ましく使用される。また、結晶粒界を有する酸化セリウム粒子径の中央値が３００〜１０００ｎｍであり、結晶子径の中央値が５０〜２００ｎｍである粒子が好ましく使用される。結晶粒界を有する酸化セリウム粒子の最大径は、３０００ｎｍ以下が好ましく、結晶子の最大径は、６００ｎｍ以下が好ましい。結晶子径が１０〜６００ｎｍのものが好ましい。 The median value of the cerium oxide particle diameter having a crystal grain boundary is preferably 60 to 1500 nm, more preferably 100 to 1200 nm, and most preferably 300 to 1000 nm. The median crystallite diameter is preferably 5 to 250 nm, more preferably 5 to 150 nm. Particles having a median cerium oxide particle diameter having a grain boundary of 300 to 1000 nm and a median crystallite diameter of 10 to 50 nm are preferably used. Further, particles having a median cerium oxide particle diameter of 300 to 1000 nm and a median crystallite diameter of 50 to 200 nm are preferably used. The maximum diameter of cerium oxide particles having crystal grain boundaries is preferably 3000 nm or less, and the maximum diameter of crystallites is preferably 600 nm or less. A crystallite diameter of 10 to 600 nm is preferable.
また、本発明により、気孔を有する砥粒を媒体に分散させたスラリーを含む研磨剤が提供される。砥粒としては酸化セリウム粒子が好ましく使用される。 The present invention also provides an abrasive containing a slurry in which abrasive grains having pores are dispersed in a medium. As the abrasive grains, cerium oxide particles are preferably used.
気孔は、ピクノメータを用いて測定した密度とＸ線リートベルト解析で求めた理論密度との比から求めた気孔率が１０〜３０％であることが好ましい。また、Ｂ．Ｊ．Ｈ．（Barret, Joyner, Halende）法により測定した細孔容積が０．０２〜０．０５ｃｍ３／ｇである気孔が好ましい。 The porosity is preferably 10 to 30% in terms of the porosity determined from the ratio between the density measured using a pycnometer and the theoretical density determined by X-ray Rietveld analysis. B. J. et al. H. Pore whose pore volume measured by the (Barret, Joyner, Halende) method is 0.02 to 0.05 cm 3 / g is preferred.
さらに、本発明により、かさ密度が６．５ｇ／ｃｍ３以下である酸化セリウム粒子を媒体に分散させたスラリーを含む研磨剤が提供される。かさ密度が５．０ｇ／ｃｍ３以上５．９ｇ／ｃｍ３以下であることが好ましい。 Furthermore, the present invention provides an abrasive containing a slurry in which cerium oxide particles having a bulk density of 6.5 g / cm 3 or less are dispersed in a medium. The bulk density is preferably 5.0 g / cm 3 or more and 5.9 g / cm 3 or less.
媒体としては、水が好ましく使用される。スラリーには分散剤を含むことができ、分散剤としては、水溶性有機高分子、水溶性陰イオン界面活性剤、水溶性非イオン性界面活性剤及び水溶性アミンから選ばれる少なくとも１種であるが好ましく、ポリアクリル酸アンモニウム塩が好ましく使用できる。 As the medium, water is preferably used. The slurry may contain a dispersant, and the dispersant is at least one selected from a water-soluble organic polymer, a water-soluble anionic surfactant, a water-soluble nonionic surfactant, and a water-soluble amine. Are preferred, and polyacrylic acid ammonium salts are preferably used.
さらに、本発明により、２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含み、粒径１μｍ以上の酸化セリウム粒子が酸化セリウム粒子全量の０．１重量％以上を占め、前記結晶粒界を有する酸化セリウム粒子は、研磨の際に崩れながら所定の基板を研磨することを特徴とする研磨剤が提供される。 Further, according to the present invention, the cerium oxide particles comprising a crystal grain boundary composed of two or more crystallites, the cerium oxide particles having a particle size of 1 μm or more occupy 0.1% by weight or more of the total amount of the cerium oxide particles, A polishing agent is provided in which a predetermined substrate is polished while cerium oxide particles having crystal grain boundaries collapse during polishing.
さらに、本発明により、２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含み、前記結晶粒界を有する酸化セリウム粒子は、研磨の際に媒体と触れていない新面を生成しながら、所定の基板を研磨することを特徴とする研磨剤が提供される。 Further, according to the present invention, the cerium oxide particles having a crystal grain boundary including two or more crystallites are formed, and the cerium oxide particles having the crystal grain boundary generate a new surface that is not in contact with the medium during polishing. An abrasive that polishes a predetermined substrate is provided.
さらに、本発明により、２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含む研磨剤であって、
（１）所定の基板を研磨した後遠心沈降法により測定した、研磨後の粒径０．５μｍ以上の酸化セリウム粒子の含有量の、同様に遠心沈降法により測定した研磨前の粒径０．５μｍ以上の酸化セリウム粒子の含有量に対する比率が、０．８以下となることを特徴とする研磨剤、
（２）所定の基板を研磨した後レーザー回折法により測定した、研磨後のＤ９９体積％の酸化セリウム粒子径の、同様にレーザー回折法により測定した研磨前のＤ９９％の酸化セリウム粒子径に対する比率が、０．４以上０．９以下となることを特徴とする研磨剤、及び、
（３）所定の基板を研磨した後レーザー回折法により測定した、研磨後のＤ９０体積％の酸化セリウム粒子径の、同様に後レーザー回折法により測定した研磨前のＤ９０％の酸化セリウム粒子径に対する比率が、０．７以上０．９５以下となることを特徴とする研磨剤
が提供される。
Further, according to the present invention, an abrasive comprising cerium oxide particles composed of two or more crystallites and having a crystal grain boundary,
(1) The content of cerium oxide particles having a particle size of 0.5 μm or more after polishing, measured by a centrifugal sedimentation method after polishing a predetermined substrate, and the particle size before polishing similarly measured by the centrifugal sedimentation method. A polishing agent characterized in that the ratio to the content of cerium oxide particles of 5 μm or more is 0.8 or less,
(2) Ratio of D99 volume% cerium oxide particle diameter after polishing measured by laser diffraction after polishing a predetermined substrate to D99% cerium oxide particle diameter before polishing similarly measured by laser diffraction Is an abrasive characterized by being 0.4 or more and 0.9 or less, and
(3) After polishing a predetermined substrate, the D90 volume% cerium oxide particle diameter after polishing measured by the laser diffraction method, similarly to the D90% cerium oxide particle diameter before polishing measured by the post laser diffraction method A polishing agent characterized in that the ratio is 0.7 or more and 0.95 or less is provided.
本発明の基板の研磨法は、上述の研磨剤を用いて所定の基板を研磨するものであり、当該所定の基板の強度が、酸化セリウム粒子の粒界破壊強度より大きいことが好ましい。所定の基板は、シリカ膜が形成された半導体チップであることができる。 The substrate polishing method of the present invention is to polish a predetermined substrate using the above-described abrasive, and the strength of the predetermined substrate is preferably larger than the grain boundary fracture strength of the cerium oxide particles. The predetermined substrate can be a semiconductor chip on which a silica film is formed.
本発明の半導体装置の製造法は、シリカ膜が形成された半導体チップを、前記の研磨剤で研磨する工程を備えるものである。 The method for producing a semiconductor device of the present invention comprises a step of polishing a semiconductor chip on which a silica film is formed with the above-mentioned abrasive.
一般に酸化セリウムは、炭酸塩、硫酸塩、蓚酸塩等のセリウム化合物を焼成することによって得られる。ＴＥＯＳ（テトラエトキシシラン）−ＣＶＤ法等で形成されるＳｉＯ２絶縁膜は、粒子径が大きく、かつ結晶歪が少ないほど、すなわち結晶性がよいほど高速研磨が可能であるが、研磨傷が入りやすい傾向がある。そこで、本発明で用いる酸化セリウム粒子は、あまり結晶性を上げないで調製される。また、半導体チップ研磨に使用することから、アルカリ金属及びハロゲン類の含有率は１ｐｐｍ以下に抑えることが好ましい。 In general, cerium oxide is obtained by firing a cerium compound such as carbonate, sulfate, or oxalate. The SiO 2 insulating film formed by TEOS (tetraethoxysilane) -CVD method, etc., can be polished at a higher speed as the particle size is larger and the crystal distortion is smaller, that is, the better the crystallinity is, but there are polishing scratches. It tends to be easy. Therefore, the cerium oxide particles used in the present invention are prepared without significantly increasing the crystallinity. Moreover, since it uses for semiconductor chip grinding | polishing, it is preferable to suppress the content rate of an alkali metal and halogens to 1 ppm or less.
本発明の研磨剤は高純度のもので、Ｎａ、Ｋ、Ｓｉ、Ｍｇ、Ｃａ、Ｚｒ、Ｔｉ、Ｎｉ、Ｃｒ、Ｆｅはそれぞれ１ｐｐｍ以下、Ａｌは１０ｐｐｍ以下である。 The abrasive | polishing agent of this invention is a highly purified thing, Na, K, Si, Mg, Ca, Zr, Ti, Ni, Cr, and Fe are 1 ppm or less respectively, and Al is 10 ppm or less.
本発明において、酸化セリウム粒子を調製する方法として焼成法が使用できる。ただし、研磨傷が入らない粒子を調製するために、できるだけ結晶性を上げない低温焼成が好ましい。セリウム化合物の酸化温度が３００℃であることから、焼成温度は４００℃以上９００℃以下が好ましい。炭酸セリウムを４００℃以上９００℃以下で５〜３００分、酸素ガス等の酸化雰囲気で焼成すること好ましい。 In the present invention, a firing method can be used as a method for preparing the cerium oxide particles. However, in order to prepare particles free from abrasive scratches, low-temperature firing that does not increase crystallinity as much as possible is preferable. Since the oxidation temperature of the cerium compound is 300 ° C, the firing temperature is preferably 400 ° C or higher and 900 ° C or lower. It is preferable to calcine cerium carbonate at 400 ° C. or higher and 900 ° C. or lower for 5 to 300 minutes in an oxidizing atmosphere such as oxygen gas.
焼成された酸化セリウムは、ジェットミル、ボールミル等の乾式粉砕、ビ−ズミル、ボールミル等の湿式粉砕で粉砕することができる。焼成酸化セリウムを粉砕した酸化セリウム粒子には、結晶子サイズの小さい単結晶粒子と結晶子サイズまで粉砕されていない粉砕粒子が含まれ、この粉砕粒子は単結晶粒子が再凝集した凝集体とは異なっており、２つ以上の結晶子から構成され結晶粒界を有している。この結晶粒界を有す粉砕粒子を含む研磨剤で研磨を行うと、研磨時の応力により破壊され活性面を発生すると推定され、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することに寄与していると考えられる。 The calcined cerium oxide can be pulverized by dry pulverization such as jet mill and ball mill, and wet pulverization such as bead mill and ball mill. The cerium oxide particles obtained by pulverizing calcined cerium oxide include single crystal particles having a small crystallite size and pulverized particles that have not been pulverized to the crystallite size. It is different and is composed of two or more crystallites and has a grain boundary. When polishing with an abrasive containing pulverized particles having crystal grain boundaries, it is presumed that the active surface is generated by being destroyed by the stress during polishing, and the surface to be polished such as the SiO 2 insulating film is polished at high speed without scratches. It is thought that it contributes to this.
本発明における酸化セリウムスラリーは、上記の方法により製造された酸化セリウム粒子を含有する水溶液又はこの水溶液から回収した酸化セリウム粒子、水及び必要に応じて分散剤からなる組成物を分散させることによって得られる。必要に応じて酸化セリウム粒子はフィルタ等で分級することができる。ここで、酸化セリウム粒子の濃度に制限はないが、懸濁液（研磨剤）の取り扱いやすさから０．５〜１０重量％の範囲が好ましい。 The cerium oxide slurry in the present invention is obtained by dispersing an aqueous solution containing cerium oxide particles produced by the above method, or a composition comprising cerium oxide particles recovered from this aqueous solution, water and, if necessary, a dispersant. It is done. If necessary, the cerium oxide particles can be classified with a filter or the like. Here, although there is no restriction | limiting in the density | concentration of a cerium oxide particle, The range of 0.5 to 10 weight% is preferable from the ease of handling of suspension (abrasive).
分散剤としては、金属イオン類を含まないものとして、アクリル酸系ポリマー、ポリビニルアルコール等の水溶性有機高分子類、ラウリル硫酸アンモニウム及びポリオキシエチレンラウリルエーテル硫酸アンモニウム等の水溶性陰イオン性界面活性剤、ポリオキシエチレンラウリルエーテル及びポリエチレングリコールモノステアレート等の水溶性非イオン性界面活性剤、並びに、モノエタノールアミン及びジエタノールアミン等の水溶性アミン類等が挙げられる。なお、アクリル酸系ポリマーには、例えば、アクリル酸重合体及びそのアンモニウム塩、メタクリル酸重合体及びそのアンモニウム塩、並びに、アクリル酸アンモニウム塩とアクリル酸アルキル（メチル、エチル又はプロピル）との共重合体などが挙げられる。 The dispersant does not contain metal ions, water-soluble organic polymers such as acrylic acid polymers, polyvinyl alcohol and the like, water-soluble anionic surfactants such as ammonium lauryl sulfate and ammonium polyoxyethylene lauryl ether sulfate, Examples thereof include water-soluble nonionic surfactants such as polyoxyethylene lauryl ether and polyethylene glycol monostearate, and water-soluble amines such as monoethanolamine and diethanolamine. Examples of acrylic acid polymers include acrylic acid polymer and ammonium salt thereof, methacrylic acid polymer and ammonium salt thereof, and co-polymerization of ammonium acrylate salt and alkyl acrylate (methyl, ethyl or propyl). Examples include coalescence.
これらのうち、ポリアクリル酸アンモニウム塩、又は、アクリル酸アンモニウム塩とアクリル酸メチルとの共重合体が好ましい。後者を用いる場合、アクリル酸アンモニウム塩とアクリル酸メチルとのモル比は、アクリル酸アンモニウム塩／アクリル酸メチルが１０／９０〜９０／１０であることが好ましい。 Of these, polyacrylic acid ammonium salt or a copolymer of ammonium acrylate salt and methyl acrylate is preferable. When the latter is used, it is preferable that the ammonium acrylate salt / methyl acrylate molar ratio is 10/90 to 90/10.
また、アクリル酸系ポリマーの重量平均分子量１０００〜２００００であることが好ましい。重量平均分子量が２００００を超えると再凝集による粒度分布の経時変化が生じやすい。重量平均分子量が１０００未満では分散性及び沈降防止の効果が充分でない場合がある。 Moreover, it is preferable that the weight average molecular weights of acrylic acid-type polymer are 1000-20000. When the weight average molecular weight exceeds 20000, the particle size distribution is likely to change over time due to reaggregation. If the weight average molecular weight is less than 1000, the dispersibility and the effect of preventing sedimentation may not be sufficient.
これらの分散剤の添加量は、スラリー中の粒子の分散性及び沈降防止性等から、酸化セリウム粒子１００重量部に対して０．０１重量部から５重量部の範囲が好ましく、その分散効果を高めるためには、分散処理時に分散機の中に粒子と同時に入れることが好ましい。酸化セリウム粒子１００重量部に対して０．０１重量部未満では沈降しやすく、５重量部を超えると再凝集による粒度分布の経時変化が生じやすい。 The amount of these dispersants added is preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the cerium oxide particles in view of the dispersibility of the particles in the slurry and the anti-settling property. In order to increase the density, it is preferable to place the particles in the disperser at the same time as the particles during the dispersion treatment. If the amount is less than 0.01 part by weight with respect to 100 parts by weight of the cerium oxide particles, the particles are likely to settle.
これらの酸化セリウム粒子を水中に分散させる方法としては、通常の撹拌機による分散処理の他に、ホモジナイザー、超音波分散機、ボールミル等を用いることができる。サブμｍオーダの酸化セリウム粒子を分散させるためには、ボールミル、振動ボールミル、遊星ボールミル、媒体撹拌式ミル等の湿式分散機を用いることが好ましい。また、スラリーのアルカリ性を高めたい場合には、分散処理時又は処理後に、アンモニア水などの金属イオンを含まないアルカリ性物質を添加することができる。 As a method for dispersing these cerium oxide particles in water, a homogenizer, an ultrasonic disperser, a ball mill, or the like can be used in addition to a dispersion treatment using a normal stirrer. In order to disperse the sub-μm order cerium oxide particles, it is preferable to use a wet disperser such as a ball mill, a vibration ball mill, a planetary ball mill, a medium stirring mill or the like. When it is desired to increase the alkalinity of the slurry, an alkaline substance that does not contain metal ions such as aqueous ammonia can be added during or after the dispersion treatment.
本発明の酸化セリウム研磨剤は、上記スラリーをそのまま使用してもよいが、Ｎ，Ｎ−ジエチルエタノ−ルアミン、Ｎ，Ｎ−ジメチルエタノ−ルアミン、アミノエチルエタノ−ルアミン、陰イオン性界面活性剤、ポリビニルアルコール、又は、上述の分散剤といった添加剤を使用形態に応じ適宜添加して研磨剤とすることができる。 The cerium oxide abrasive of the present invention may use the above slurry as it is, but N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethylethanolamine, anionic surfactant Additives such as polyvinyl alcohol or the above-mentioned dispersants can be appropriately added depending on the use form to obtain an abrasive.
本発明のスラリーに分散される結晶粒界を有する酸化セリウム粒子径の中央値は６０〜１５００ｎｍが好ましく、結晶子径の中央値は５〜２５０ｎｍが好ましい。 The median value of the cerium oxide particle diameter having the crystal grain boundaries dispersed in the slurry of the present invention is preferably 60 to 1500 nm, and the median value of the crystallite diameter is preferably 5 to 250 nm.
結晶粒界を有する酸化セリウム粒子径の中央値が６０ｎｍ未満、又は結晶子径の中央値が５ｎｍ未満であれば、ＳｉＯ２絶縁膜等の被研磨面を高速に研磨することができ難くなる傾向があり、結晶粒界を有する酸化セリウム粒子径の中央値が１５００ｎｍを超える、又は結晶子の中央値が２５０ｎｍを超えると、ＳｉＯ２絶縁膜等の被研磨面に傷が発生しやすくなる。結晶粒界を有する酸化セリウム粒子径の最大値が３０００ｎｍを超えると、ＳｉＯ２絶縁膜等の被研磨面に傷が発生しやすくなる。結晶粒界を有する酸化セリウム粒子は、全酸化セリウム粒子の５〜１００体積％であることが好ましく、５体積％未満の場合はＳｉＯ２絶縁膜等の被研磨面に傷が発生しやすくなる。 If the median diameter of cerium oxide particles having crystal grain boundaries is less than 60 nm, or the median crystallite diameter is less than 5 nm, the surface to be polished such as a SiO 2 insulating film tends to be difficult to polish at high speed. When the median value of the cerium oxide particle diameter having crystal grain boundaries exceeds 1500 nm or the median value of crystallites exceeds 250 nm, the surface to be polished such as the SiO 2 insulating film is likely to be damaged. If the maximum value of the cerium oxide particle diameter having a crystal grain boundary exceeds 3000 nm, the surface to be polished such as the SiO 2 insulating film is likely to be damaged. The cerium oxide particles having a grain boundary are preferably 5 to 100% by volume of the total cerium oxide particles, and if it is less than 5% by volume, the surface to be polished such as the SiO 2 insulating film is likely to be damaged.
上記の酸化セリウム粒子では、結晶子の最大径は６００ｎｍ以下が好ましく、結晶子径は１０〜６００ｎｍであることが好ましい。結晶子が６００ｎｍを超えると傷が発生しやすく、１０ｎｍ未満であると研磨速度が小さくなる傾向にある。 In the cerium oxide particles, the maximum crystallite diameter is preferably 600 nm or less, and the crystallite diameter is preferably 10 to 600 nm. If the crystallite exceeds 600 nm, scratches are likely to occur, and if it is less than 10 nm, the polishing rate tends to decrease.
本発明で、結晶子径及び結晶粒界を有する酸化セリウム粒子径は走査型電子顕微鏡（例えば（株）日立製作所製Ｓ−９００型）による観察で測定する。なお、粒子の粒子径は、その粒子の長径と短径とから求める。すなわち、その粒子の長径と短径とを測定し、長径と短径との積の平方根を粒子径とする。また、こうして決められた粒子径から求められる球の体積を、その粒子の体積とする。 In the present invention, the cerium oxide particle diameter having a crystallite diameter and a crystal grain boundary is measured by observation with a scanning electron microscope (for example, S-900 type manufactured by Hitachi, Ltd.). The particle diameter of the particle is determined from the major axis and minor axis of the particle. That is, the major axis and minor axis of the particle are measured, and the square root of the product of the major axis and the minor axis is taken as the particle diameter. Further, the volume of the sphere obtained from the particle diameter determined in this way is defined as the volume of the particle.
また、中央値は、体積粒子径分布の中央値であり、粒子径の細かいものからその粒子の体積割合を積算していき５０％になったときの粒子径を意味する。すなわち、ある区間Δの粒子径の範囲に体積割合Ｖｉ％の量の粒子が存在するとき、区間Δの平均粒子径をｄｉとすると粒子径ｄｉの粒子がＶｉ体積％存在するとする。粒子径ｄｉの小さい方から粒子の存在割合Ｖｉ（体積％）を積算していき、Ｖｉ＝５０％になったときのｄｉを中央値とする。 The median is the median of the volume particle size distribution, and means the particle size when the volume ratio of the particles is accumulated from the finer particle size to 50%. That is, the particles ranging in volume fraction V i% of the amount of the particle diameter of a certain section Δ is when present, an average particle diameter d i that the particles having a particle size d i of the interval Δ is present V i vol% . Write continue integrating the existing ratio of the particles V i (vol%) of small particle size d i, the d i when becomes V i = 50% and median.
本発明のスラリーに分散される気孔を有する酸化セリウム粒子の気孔率は１０〜３０％であることが好ましい。この気孔率の求め方は、ピクノメータを用いて測定（純水、２０℃）した密度とＸ線リートベルト解析で求めた理論密度の比から算出した。気孔を有する酸化セリウム粒子の細孔容積が０．０２〜０．０５ｃｍ３／ｇであることが好ましい。 The porosity of the cerium oxide particles having pores dispersed in the slurry of the present invention is preferably 10 to 30%. This porosity was calculated from the ratio of the density measured with a pycnometer (pure water, 20 ° C.) and the theoretical density determined by X-ray Rietveld analysis. The pore volume of the cerium oxide particles having pores is preferably 0.02 to 0.05 cm 3 / g.
気孔率が１０％未満、又は、細孔容積が０．０２ｃｍ３／ｇ未満であると、ＳｉＯ２絶縁膜等の被研磨面を高速に研磨することができるが、研磨傷が発生しやすくなる。また、気孔率が３０％を超える、又は、細孔容積が０．０５ｃｍ３／ｇを超えると、ＳｉＯ２絶縁膜等の被研磨面を研磨傷は入らないが、研磨速度が遅くなる傾向にある。 When the porosity is less than 10% or the pore volume is less than 0.02 cm 3 / g, the surface to be polished such as the SiO 2 insulating film can be polished at high speed, but polishing scratches are likely to occur. . Further, if the porosity exceeds 30% or the pore volume exceeds 0.05 cm 3 / g, the polishing surface such as the SiO 2 insulating film will not be scratched, but the polishing rate tends to be slow. is there.
また、本発明では、かさ密度が６．５ｇ／ｃｍ３以下である酸化セリウム粒子が分散しているスラリーが提供される。酸化セリウムのかさ密度が６．５ｇ／ｃｍ３を超えると、ＳｉＯ２絶縁膜の被研磨面に傷が発生する。酸化セリウムのかさ密度は５．０〜５．９ｇ／ｃｍ３が好ましく、この下限値未満であると研磨速度が小さくなり、上限値を超えると傷が発生しやすい。なお、本明細書で用いたかさ密度は、ピクノメータで測定した粉体の密度である。測定に際してピクノメータに注入する液体には純水を使用し、２０℃で測定した。 In the present invention, a slurry in which cerium oxide particles having a bulk density of 6.5 g / cm 3 or less are dispersed is provided. When the bulk density of cerium oxide exceeds 6.5 g / cm 3 , scratches occur on the polished surface of the SiO 2 insulating film. The bulk density of cerium oxide is preferably 5.0 to 5.9 g / cm 3 , and if it is less than this lower limit value, the polishing rate is reduced, and if it exceeds the upper limit value, scratches are likely to occur. In addition, the bulk density used in this specification is the density of the powder measured with a pycnometer. In the measurement, pure water was used as a liquid to be injected into the pycnometer, and measurement was performed at 20 ° C.
本発明のスラリーに分散された酸化セリウム粒子を構成する一次粒子のアスペクト比は１〜２、中央値１．３が好ましい。アスペクト比は、走査型電子顕微鏡（例えば（株）日立製作所製 Ｓ−９００型）による観察で測定する。 The aspect ratio of the primary particles constituting the cerium oxide particles dispersed in the slurry of the present invention is preferably 1 to 2, and the median value is 1.3. The aspect ratio is measured by observation with a scanning electron microscope (for example, S-900 type manufactured by Hitachi, Ltd.).
本発明のスラリーのｐＨは、７以上１０以下が好ましく、８以上９以下がより好ましい。 The pH of the slurry of the present invention is preferably 7 or more and 10 or less, and more preferably 8 or more and 9 or less.
なお、スラリーは、ｐＨを調整した後、ポリエチレン等の容器に入れ５〜５５℃で７日以上、より好ましくは３０日以上放置してから使用すれば、傷の発生が少なくなる。本発明のスラリーは、分散性に優れ、沈降速度が遅く、直径１０ｃｍ高さ１ｍの円柱容器内のどの高さでも、２時間放置濃度変化率が１０％未満である。 If the slurry is used after being adjusted in pH and then placed in a container of polyethylene or the like at 5 to 55 ° C. for 7 days or more, more preferably 30 days or more, the generation of scratches is reduced. The slurry of the present invention is excellent in dispersibility, has a slow sedimentation rate, and has a 2-hour standing concentration change rate of less than 10% at any height in a cylindrical container having a diameter of 10 cm and a height of 1 m.
また、本発明では、２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含むもので、粒径１μｍ以上の酸化セリウム粒子が酸化セリウム粒子全量の０．１重量％以上を占め、結晶粒界を有する酸化セリウム粒子は、所定の基板を研磨する際、崩れながら研磨する研磨剤が提供される。粒径１μｍ以上の酸化セリウム粒子の含有量は、０．１〜５０重量％であることが好ましく、０．１〜３０重量％であることがより好ましい。 In the present invention, the cerium oxide particles having a grain boundary composed of two or more crystallites are included, and the cerium oxide particles having a particle diameter of 1 μm or more occupy 0.1% by weight or more of the total amount of the cerium oxide particles. The cerium oxide particles having crystal grain boundaries are provided with an abrasive that polishes a predetermined substrate while being broken. The content of cerium oxide particles having a particle size of 1 μm or more is preferably 0.1 to 50% by weight, and more preferably 0.1 to 30% by weight.
粒径１μｍ以上の酸化セリウム粒子の含有量の測定は、液中パーティクルカウンタを用いて、粒子により遮られた透過光強度を測定することにより行い、測定装置としては例えば、Particle Sizing System, Inc.製のmodel 770 AccuSizer（商品名）を使用することができる。 The content of cerium oxide particles having a particle size of 1 μm or more is measured by measuring the transmitted light intensity blocked by the particles using an in-liquid particle counter. As a measuring apparatus, for example, Particle Sizing System, Inc. The model 770 AccuSizer (trade name) made by the company can be used.
また、本発明では、所定の基板を研磨する際、結晶粒界を有する酸化セリウム粒子が、媒体と触れていない新面を生成しながら研磨する研磨剤が提供される。 The present invention also provides an abrasive for polishing a predetermined substrate while generating a new surface in which cerium oxide particles having crystal grain boundaries do not come into contact with the medium.
さらに、本発明では、基板を研磨した後遠心沈降法により測定した、研磨後の０．５μｍ以上の酸化セリウム粒子含有量の、研磨前の含有量に対する比率が、０．００１以上となる研磨剤が提供される。なお、遠心沈降法は、遠心力により沈降させた粒子を透過光の強度により酸化セリウム粒子含有量を測定するものである。測定装置には、例えば島津製作所ＳＡ−ＣＰ４Ｌ（商品名）を使用することができる。 Further, in the present invention, the polishing agent in which the ratio of the cerium oxide particle content of 0.5 μm or more after polishing measured by the centrifugal sedimentation method after polishing the substrate to the content before polishing becomes 0.001 or more. Is provided. The centrifugal sedimentation method measures the content of cerium oxide particles by the intensity of transmitted light from particles sedimented by centrifugal force. For example, Shimadzu SA-CP4L (trade name) can be used as the measuring device.
また、本発明では、基板を研磨した後レーザー回折法により測定した、研磨後のＤ９９体積％の酸化セリウム粒子径の、研磨前のＤ９９％の酸化セリウム粒子径に対する比率が、０．４以上０．９以下となる研磨剤が提供される。 In the present invention, the ratio of the D99 volume% cerium oxide particle diameter after polishing measured by laser diffraction after polishing the substrate to the D99% cerium oxide particle diameter before polishing is 0.4 or more and 0. A polishing agent of less than or equal to 9 is provided.
また、本発明の研磨剤では、所定の基板を研磨した後、レーザー回折法により測定した研磨後のＤ９０体積％の酸化セリウム粒子径と研磨前のＤ９０％の酸化セリウム粒子径との比が０．７以上０．９５以下となる。 In the abrasive of the present invention, after polishing a predetermined substrate, the ratio of the D90 volume% cerium oxide particle diameter after polishing measured by laser diffraction method to the D90% cerium oxide particle diameter before polishing is 0. 7 or more and 0.95 or less.
なお、所定の基板を研磨した後とは、研磨対象となる基板を保持するための基板取り付け用吸着パッドを貼り付けたホルダーに所定の基板をセットし、多孔質ウレタン樹脂製の研磨パッドを貼り付けた定盤上に被研磨面を下にしてホルダーを載せ、さらに加工荷重が３００ｇ／ｃｍ２になるように重しを載せ、定盤上に上記の研磨剤を５０ｍｌ／分の速度で滴下しながら定盤を３０ｒｐｍで一時間回転させることにより被研磨面を研磨した後を意味する。その際、研磨後の研磨剤は循環させて再使用し、研磨剤の総量は７５０ｍｌとする。 Note that after polishing a predetermined substrate, the predetermined substrate is set in a holder to which a suction pad for mounting a substrate for holding the substrate to be polished is attached, and a polishing pad made of porous urethane resin is attached. Place the holder on the surface plate attached with the surface to be polished facing down, place a weight so that the processing load is 300 g / cm 2 , and drop the above abrasive on the surface plate at a rate of 50 ml / min. It means after the surface to be polished is polished by rotating the surface plate for 1 hour at 30 rpm. At that time, the abrasive after polishing is circulated and reused, and the total amount of abrasive is 750 ml.
レーザ回折法による測定は、例えば、マルバーンインスツルメンツ社製Master Sizer microplus、屈折率：１．９２８５、光源：Ｈｅ−Ｎｅレーザ、吸収０）によって行うことができる。 The measurement by the laser diffraction method can be performed by, for example, Master Sizer microplus manufactured by Malvern Instruments, refractive index: 1.9285, light source: He—Ne laser, absorption 0).
また、Ｄ９９％、Ｄ９０％は、体積粒子径分布において粒子径の細かいものからその粒子の体積割合を積算していき、それぞれ９９％、９０％になったときの粒子径を意味する。 Further, D99% and D90% mean the particle diameters when the volume ratio of the particles is accumulated from the finer particle diameter in the volume particle diameter distribution to 99% and 90%, respectively.
本発明の酸化セリウム研磨剤が使用される無機絶縁膜としては、ＳｉＨ４又はテトラエトキシシランをＳｉ源とし、酸素又はオゾンを酸素源としたＣＶＤ法により形成されたＳｉＯ２膜が挙げられる。 Examples of the inorganic insulating film in which the cerium oxide abrasive of the present invention is used include a SiO 2 film formed by a CVD method using SiH 4 or tetraethoxysilane as a Si source and oxygen or ozone as an oxygen source.
所定の基板として、回路素子とアルミニウム配線が形成された段階の半導体基板、回路素子が形成された段階の半導体基板等の半導体基板上にＳｉＯ２絶縁膜層が形成された基板等が使用できる。また、半導体分離（シャロー・トレンチ分離）の目的で形成されたＳｉＯ２絶縁膜を含有する基板も使用できる。このような半導体基板上に形成されたＳｉＯ２絶縁膜層を、上記研磨剤で研磨することによって、ＳｉＯ２絶縁膜層表面の凹凸を解消し、半導体基板全面に渡って平滑な面とする。ここで、研磨する装置としては、半導体基板を保持するホルダーと研磨布（パッド）を貼り付けた（回転数が変更可能なモータ等を取り付けてある）定盤を有する一般的な研磨装置が使用できる。研磨布としては、一般的な不織布、発泡ポリウレタン、多孔質フッ素樹脂などが使用でき、特に制限がない。また、研磨布にはスラリーが溜まるような溝加工を施すことが好ましい。研磨条件に制限はないが、定盤の回転速度は、半導体が飛び出さないように１００ｒｐｍ以下の低回転が好ましく、半導体基板にかける圧力は、研磨後に傷が発生しないように１ｋｇ／ｃｍ２以下が好ましい。研磨している間、研磨布にはスラリーをポンプ等で連続的に供給する。この供給量に制限はないが、研磨布の表面が常にスラリーで覆われていることが好ましい。 As the predetermined substrate, a substrate in which a SiO 2 insulating film layer is formed on a semiconductor substrate such as a semiconductor substrate in which a circuit element and an aluminum wiring are formed, a semiconductor substrate in a stage in which a circuit element is formed, and the like can be used. A substrate containing a SiO 2 insulating film formed for the purpose of semiconductor isolation (shallow trench isolation) can also be used. By polishing the SiO 2 insulating film layer formed on such a semiconductor substrate with the above-described polishing agent, unevenness on the surface of the SiO 2 insulating film layer is eliminated, and the entire surface of the semiconductor substrate is made smooth. Here, as a polishing apparatus, a general polishing apparatus having a surface plate with a holder for holding a semiconductor substrate and a polishing cloth (pad) attached (a motor etc. capable of changing the number of rotations) is used. it can. As an abrasive cloth, a general nonwoven fabric, a polyurethane foam, a porous fluororesin, etc. can be used, and there is no restriction | limiting in particular. Further, it is preferable that the polishing cloth is grooved so that slurry is accumulated. The polishing conditions are not limited, but the rotation speed of the surface plate is preferably low rotation of 100 rpm or less so that the semiconductor does not jump out, and the pressure applied to the semiconductor substrate is 1 kg / cm 2 or less so that scratches do not occur after polishing. Is preferred. During polishing, slurry is continuously supplied to the polishing cloth with a pump or the like. Although there is no restriction | limiting in this supply amount, It is preferable that the surface of polishing cloth is always covered with the slurry.
研磨終了後の半導体基板は、流水中で良く洗浄後、スピンドライヤ等を用いて半導体基板上に付着した水滴を払い落としてから乾燥させることが好ましい。このようにして平坦化されたＳｉＯ２絶縁膜層の上に、第２層目のアルミニウム配線を形成し、その配線間及び配線上に再度上記方法により、ＳｉＯ２絶縁膜を形成後、上記酸化セリウム研磨剤を用いて研磨することによって、絶縁膜表面の凹凸を解消し、半導体基板全面に渡って平滑な面とする。この工程を所定数繰り返すことにより、所望の層数の半導体を製造する。 The semiconductor substrate after completion of polishing is preferably washed in running water and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. A second-layer aluminum wiring is formed on the thus planarized SiO 2 insulating film layer, and after the SiO 2 insulating film is formed again between the wirings and on the wiring by the above method, the oxidation By polishing with a cerium abrasive, unevenness on the surface of the insulating film is eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate. By repeating this process a predetermined number of times, a desired number of semiconductor layers are manufactured.
本発明の酸化セリウム研磨剤は、半導体基板に形成されたＳｉＯ２絶縁膜だけでなく、所定の配線を有する配線板に形成されたＳｉＯ２絶縁膜、ガラス、窒化ケイ素等の無機絶縁膜、フォトマスク・レンズ・プリズム等の光学ガラス、ＩＴＯ（Indium Tin Oxide）等の無機導電膜、ガラス及び結晶質材料で構成される光集積回路・光スイッチング素子・光導波路、光ファイバ−の端面、シンチレ−タ等の光学用単結晶、固体レ−ザ単結晶、青色レ−ザ用ＬＥＤサファイア基板、ＳｉＣ、ＧａＰ、ＧａＡＳ等の半導体単結晶、磁気ディスク用ガラス基板、磁気ヘッド等を研磨するために使用される。 Cerium oxide abrasive of the present invention is not only SiO 2 insulating film formed on a semiconductor substrate, SiO 2 insulating film formed on the wiring board having a predetermined wiring, glass, inorganic insulating films such as silicon nitride, Photo Optical glass such as masks, lenses and prisms, inorganic conductive films such as ITO (Indium Tin Oxide), optical integrated circuits composed of glass and crystalline materials, optical switching elements, optical waveguides, end faces of optical fibers, scintillators Used to polish optical single crystals such as lasers, solid laser single crystals, LED sapphire substrates for blue lasers, semiconductor single crystals such as SiC, GaP, and GaAS, glass substrates for magnetic disks, magnetic heads, etc. Is done.
このように本発明において所定の基板とは、ＳｉＯ２絶縁膜が形成された半導体基板、ＳｉＯ２絶縁膜が形成された配線板、ガラス、窒化ケイ素等の無機絶縁膜、フォトマスク・レンズ・プリズム等の光学ガラス、ＩＴＯ等の無機導電膜、ガラス及び結晶質材料で構成される光集積回路・光スイッチング素子・光導波路、光ファイバ−の端面、シンチレ−タ等の光学用単結晶、固体レ−ザ単結晶、青色レ−ザ用ＬＥＤサファイア基板、ＳｉＣ、ＧａＰ、ＧａＡＳ等の半導体単結晶、磁気ディスク用ガラス基板、磁気ヘッド等を含む。 The predetermined substrate in the present invention as described above, SiO 2 semiconductor substrate on which an insulating film is formed, SiO 2 insulating film is formed wiring board, glass, inorganic insulating films such as silicon nitride, photomask lenses and prisms Optical glass such as ITO, inorganic conductive films such as ITO, optical integrated circuits / optical switching elements / optical waveguides composed of glass and crystalline materials, optical fiber end faces, optical single crystals such as scintillators, solid state lasers, etc. -The single crystal, LED sapphire substrate for blue laser, semiconductor single crystal such as SiC, GaP, GaAS, etc., glass substrate for magnetic disk, magnetic head, etc.
（１）酸化セリウム粒子の調製
ａ．酸化セリウム粒子Ａの調製
炭酸セリウム水和物２ｋｇを白金製容器に入れ、８００℃で、２時間、空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末の相同定をＸ線回折法で行ない、酸化セリウムであることを確認した。
(1) Preparation of cerium oxide particles a. Preparation of Cerium Oxide Particle A 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined in air at 800 ° C. for 2 hours to obtain about 1 kg of yellowish white powder. The phase of this powder was identified by X-ray diffraction and confirmed to be cerium oxide.
得られた焼成粉末の粒子径は３０〜１００μｍであった。焼成粉末粒子の表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が１９０ｎｍ、最大値が５００ｎｍであった。 The particle size of the obtained fired powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 190 nm and the maximum value was 500 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕後の粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子の他に、１μｍから３μｍの大きな多結晶粒子と０．５から１μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ａと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to small single crystal particles having a size equivalent to the crystallite diameter, large polycrystalline particles of 1 to 3 μm and polycrystalline particles of 0.5 to 1 μm were mixed. It was. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles A.
ｂ．酸化セリウム粒子Ｂの調製
炭酸セリウム水和物２ｋｇを白金製容器に入れ、７５０℃で、２時間、空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末の相同定をＸ線回折法で行い、酸化セリウムであることを確認した。焼成粉末の粒子径は３０〜１００μｍであった。
b. Preparation of Cerium Oxide Particle B 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined in the air at 750 ° C. for 2 hours to obtain about 1 kg of yellowish white powder. The powder was phase-identified by X-ray diffraction and confirmed to be cerium oxide. The particle diameter of the fired powder was 30 to 100 μm.
得られた焼成粉末の粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が１４１ｎｍ、最大値が４００ｎｍであった。 When the particle surface of the obtained fired powder was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 141 nm, and the maximum value was 400 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕後の粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子の他に、１μｍから３μｍの大きな多結晶粒子と０．５〜１μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ｂと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. When the pulverized particles were observed with a scanning electron microscope, large single particles of 1 to 3 μm and polycrystalline particles of 0.5 to 1 μm were mixed in addition to small single crystal particles having the same size as the crystallite diameter. It was. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles B.
（２）研磨剤の調製
ａ．研磨剤Ａ，Ｂの調製
上記（１）で得られた酸化セリウム粒子Ａ又はＢ１ｋｇと、ポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと、脱イオン水８９７７ｇとを混合し、攪拌しながら超音波を１０分間照射して、酸化セリウム粒子を分散させ、スラリーを得た。
(2) Preparation of abrasive a. Preparation of abrasives A and B 1 kg of the cerium oxide particles A or B obtained in (1) above, 23 g of an ammonium polyacrylate aqueous solution (40% by weight), and 8977 g of deionized water were mixed and stirred while stirring. A sound wave was irradiated for 10 minutes to disperse the cerium oxide particles to obtain a slurry.
得られたスラリーを１μｍフィルタでろ過をし、さらに脱イオン水を加えることにより、固形分３重量％の研磨剤を得た。酸化セリウム粒子Ａ又はＢから得られた研磨剤を、以下、それぞれ、研磨剤Ａ又はＢと呼ぶ。得られた研磨剤Ａ，ＢのｐＨは、それぞれ８．３、８．３であった。 The obtained slurry was filtered with a 1 μm filter, and deionized water was added to obtain an abrasive having a solid content of 3% by weight. The abrasive obtained from the cerium oxide particles A or B is hereinafter referred to as abrasive A or B, respectively. The resulting abrasives A and B had pH 8.3 and 8.3, respectively.
研磨剤中の粒子を走査型電子顕微鏡で観察するために、各研磨剤をそれぞれ適当な濃度に希釈した後乾燥させて、中に含まれる多結晶粒子径を測定したところ、酸化セリウム粒子Ａを用いた研磨剤Ａでは、中央値が８２５ｎｍ、最大値が１２３０ｎｍであった。また、酸化セリウム粒子Ｂを用いた研磨剤Ｂでは、中央値が７６８ｎｍ、最大値が１２００ｎｍであった。 In order to observe the particles in the abrasive with a scanning electron microscope, each abrasive was diluted to an appropriate concentration and then dried, and the polycrystalline particle size contained therein was measured. The abrasive A used had a median value of 825 nm and a maximum value of 1230 nm. Moreover, in the abrasive | polishing agent B using the cerium oxide particle B, the median value was 768 nm and the maximum value was 1200 nm.
研磨剤Ａを乾燥し、得られた粒子の密度（かさ密度）を、ピクノメータを用いて測定したところ、５．７８ｇ／ｍｌであった。また、Ｘ線リートベルト解析による理論密度は７．２０１ｇ／ｍｌであった。これらの値から気孔率を算出したところ、１９．８％であった。スラリーを乾燥して得られた粒子についてＢ．Ｊ．Ｈ．法によりその細孔容積を測定したところ、０．０３３ｍｌ／ｇであった。 The abrasive A was dried, and the density (bulk density) of the obtained particles was measured with a pycnometer to be 5.78 g / ml. The theoretical density by X-ray Rietveld analysis was 7.201 g / ml. The porosity was calculated from these values and found to be 19.8%. B. Particles obtained by drying the slurry J. et al. H. When the pore volume was measured by the method, it was 0.033 ml / g.
次に、研磨剤の分散性及び分散粒子の電荷を調べるため、研磨剤Ａ，Ｂのゼータ電位を調べた。すなわち、対向する側面の両側に白金製電極を取り付けてある測定セルに酸化セリウムスラリーを入れ、両電極に１０Ｖの電圧を印加した。電圧を印加することにより電荷を持った分散粒子は、その電荷と反対の極を持つ電極側に移動する。この移動速度を求めることにより粒子のゼータ電位を求めた。ゼータ電位測定の結果、研磨剤Ａ，Ｂとも、分散粒子がそれぞれマイナスに荷電し、−５０ｍＶ、−６３ｍＶと絶対値が大きく分散性が良好であることを確認した。 Next, in order to investigate the dispersibility of the abrasive and the charge of the dispersed particles, the zeta potentials of the abrasives A and B were examined. That is, cerium oxide slurry was put into a measurement cell having platinum electrodes attached to both sides of the opposite side surfaces, and a voltage of 10 V was applied to both electrodes. Dispersed particles having a charge by applying a voltage move to the side of the electrode having a pole opposite to the charge. By determining the moving speed, the zeta potential of the particles was determined. As a result of the zeta potential measurement, it was confirmed that both of the abrasives A and B had negatively charged dispersed particles and had large absolute values of −50 mV and −63 mV and good dispersibility.
ｂ．研磨剤Ａ’，Ｂ’の調製
酸化セリウム粒子Ａ又はＢ１ｋｇと、ポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと、脱イオン水８９７７ｇとを混合し、攪拌しながら超音波を１０分間照射して、酸化セリウム粒子を分散させ、スラリーを得た。
b. Preparation of abrasives A ′ and B ′ 1 kg of cerium oxide particles A or B, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight), and 8977 g of deionized water are mixed and irradiated with ultrasonic waves for 10 minutes while stirring. Then, cerium oxide particles were dispersed to obtain a slurry.
得られたスラリーを０．８μｍフィルタでろ過をし、さらに脱イオン水を加えることにより、固形分３重量％の研磨剤を得た。酸化セリウム粒子Ａ又はＢから得られた研磨剤を、以下、それぞれ、研磨剤Ａ’又はＢ’と呼ぶ。得られた研磨剤Ａ’，Ｂ’のｐＨは、それぞれ８．３、８．３であった。 The obtained slurry was filtered through a 0.8 μm filter, and deionized water was further added to obtain an abrasive having a solid content of 3% by weight. The abrasive obtained from the cerium oxide particles A or B is hereinafter referred to as abrasive A ′ or B ′, respectively. The resulting abrasives A ′ and B ′ had pH of 8.3 and 8.3, respectively.
研磨剤中の粒子を走査型電子顕微鏡で観察するために、研磨剤Ａ’，Ｂ’をそれぞれ適当な濃度に希釈して乾燥させた後、含まれる多結晶粒子の粒径を測定したところ、酸化セリウム粒子Ａを用いて調製された研磨剤Ａ’では、中央値が４５０ｎｍ、最大値が９８０ｎｍであった。また、酸化セリウム粒子Ｂを用いて調製された研磨剤Ｂ’では、中央値が４６２ｎｍ、最大値が１０００ｎｍであった。 In order to observe the particles in the abrasive with a scanning electron microscope, each of the abrasives A ′ and B ′ was diluted to an appropriate concentration and dried, and then the particle size of the polycrystalline particles contained was measured. The abrasive A ′ prepared using the cerium oxide particles A had a median value of 450 nm and a maximum value of 980 nm. Moreover, in the abrasive | polishing agent B 'prepared using the cerium oxide particle B, the median value was 462 nm and the maximum value was 1000 nm.
次に、研磨剤中の粒子の分散性、及び、分散粒子の電荷を調べるため、上述の研磨剤Ａ，Ｂの場合と同様にして研磨剤Ａ’，Ｂ’のゼータ電位を調べたところ、いずれの研磨剤の分散粒子もマイナスに荷電し、それぞれ−５３ｍＶ、−６３ｍＶと絶対値が大きく分散性が良好であることが確認された。 Next, in order to investigate the dispersibility of the particles in the abrasive and the charge of the dispersed particles, the zeta potential of the abrasives A ′ and B ′ was examined in the same manner as in the above-described abrasives A and B. It was confirmed that the dispersed particles of any abrasive were negatively charged and had large absolute values of -53 mV and -63 mV, respectively, and good dispersibility.
（３）絶縁膜の研磨
ホルダーに貼り付けられた基板取り付け用吸着パッドに、ＴＥＯＳ−プラズマＣＶＤ法でＳｉＯ２絶縁膜を形成したＳｉウエハを吸着させて固定した。このホルダーを、Ｓｉウエハを保持したまま、絶縁膜面を下にして、多孔質ウレタン樹脂製の研磨パッドを貼り付けた定盤上に載置し、さらに加工荷重が３００ｇ／ｃｍ２になるように重しを載せた。
(3) Polishing of insulating film The Si wafer on which the SiO 2 insulating film was formed was adsorbed and fixed to the adsorption pad for substrate attachment affixed to the holder by TEOS-plasma CVD method. The holder is placed on a surface plate with a porous urethane resin polishing pad affixed with the insulating film face down while holding the Si wafer, so that the processing load becomes 300 g / cm 2. The weight was put on.
次に、定盤上に本実施例で調製した研磨剤Ａ，Ｂ，Ａ’又はＢ’（固形分：３重量％）を５０ｍｌ／分の速度で滴下しながら、定盤を３０ｒｐｍで２分間回転させ、Ｓｉウエハ表面の絶縁膜を研磨した。研磨後、ウエハをホルダーから取り外し、流水で良く洗浄した後、超音波洗浄機によりさらに２０分間洗浄した。洗浄後、ウエハをスピンドライヤで水滴を除去し、１２０℃の乾燥機で１０分間乾燥させた。 Next, while the abrasive A, B, A ′ or B ′ (solid content: 3% by weight) prepared in this example was dropped on the surface plate at a rate of 50 ml / min, the surface plate was kept at 30 rpm for 2 minutes. The insulating film on the surface of the Si wafer was polished by rotating. After polishing, the wafer was removed from the holder, thoroughly washed with running water, and then further washed with an ultrasonic cleaner for 20 minutes. After cleaning, the wafer was removed of water droplets with a spin dryer and dried with a 120 ° C. dryer for 10 minutes.
乾燥後のウエハについて、光干渉式膜厚測定装置を用いて、研磨前後のＳｉＯ２絶縁膜の膜厚変化を測定した結果、研磨剤Ａを用いた場合は６００ｎｍ（研磨速度：３００ｎｍ／分）、研磨剤Ｂを用いた場合は５８０ｎｍ（研磨速度：２９０ｎｍ／分）、研磨剤Ａ’を用いた場合は５９０ｎｍ（研磨速度：２９５ｎｍ／分）、研磨剤Ｂ’を用いた場合は５６０ｎｍ（研磨速度：２８０ｎｍ／分）の絶縁膜がそれぞれ削られ、いずれの研磨剤を用いた場合も、ウエハ全面に渡って均一の厚みになっていることがわかった。また、光学顕微鏡を用いて絶縁膜表面を観察したところ、いずれの場合も明確な傷は見られなかった。 As a result of measuring the film thickness change of the SiO 2 insulating film before and after polishing using a light interference type film thickness measuring device, the dried wafer was 600 nm (polishing rate: 300 nm / min). When abrasive B is used, 580 nm (polishing rate: 290 nm / min), when abrasive A ′ is used, 590 nm (polishing rate: 295 nm / min), and when abrasive B ′ is used, 560 nm (polishing) It was found that the insulating film at a speed of 280 nm / min was respectively cut, and even when any abrasive was used, the thickness was uniform over the entire surface of the wafer. Further, when the surface of the insulating film was observed using an optical microscope, no clear scratch was observed in any case.
また、研磨剤Ａを用い、上述の場合と同様にしてＳｉウエハ表面のＳｉＯ２絶縁膜を研磨し、研磨後の研磨剤Ａの粒径を遠心沈降式粒度分布計により測定したところ、０．５μｍ以上の粒子含有量（体積％）の、研磨前の値に対する比率は０．３８５であった。ただし、研磨の際の定盤を回転させる時間は１時間とし、順次交換しながら１５枚のＳｉウエハを研磨した。また、研磨後の研磨剤は循環させて再使用し、研磨剤の総量は７５０ｍｌとした。研磨後の研磨剤Ａの粒径をレーザー散乱式粒度分布計により測定したところ、Ｄ９９％およびＤ９０％における粒径は研磨前の値に対してそれぞれ０．４９１、０．８０４であった。これらの値から、研磨剤Ａは崩れながら研磨する性質及び媒体と触れていない新面を生成しながら研磨する性質を備えていると考えられる。 Further, the polishing agent A was used to polish the SiO 2 insulating film on the Si wafer surface in the same manner as described above, and the particle size of the polishing agent A after polishing was measured with a centrifugal sedimentation type particle size distribution meter. The ratio of the particle content (volume%) of 5 μm or more to the value before polishing was 0.385. However, the time for rotating the platen during polishing was 1 hour, and 15 Si wafers were polished while being sequentially replaced. The abrasive after polishing was circulated and reused, and the total amount of abrasive was 750 ml. The particle size of abrasive A after polishing was measured with a laser scattering particle size distribution meter. The particle sizes at D99% and D90% were 0.491 and 0.804, respectively, with respect to the values before polishing. From these values, it is considered that the polishing agent A has the property of polishing while being broken and the property of polishing while generating a new surface not touching the medium.
（１）酸化セリウム粒子の調製
ａ．酸化セリウム粒子Ｃの調製
炭酸セリウム水和物２ｋｇを白金製容器に入れ、７００℃で２時間、空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末の相同定をＸ線回折法で行ない、酸化セリウムであることを確認した。得られた焼成粉末の粒子径は３０〜１００μｍであった。焼成粉末粒子の表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が５０ｎｍ、最大値が１００ｎｍであった。
(1) Preparation of cerium oxide particles a. Preparation of Cerium Oxide Particle C 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined in the air at 700 ° C. for 2 hours to obtain about 1 kg of yellowish white powder. The phase of this powder was identified by X-ray diffraction and confirmed to be cerium oxide. The particle size of the obtained fired powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 50 nm and the maximum value was 100 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕した粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子粒子の他に、２μｍから４μｍの大きな多結晶粒子と０．５から１．２μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ｃと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to small single crystal particle particles having a size equivalent to the crystallite size, large polycrystalline particles of 2 to 4 μm and polycrystalline particles of 0.5 to 1.2 μm were obtained. It was mixed. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles C.
ｂ．酸化セリウム粒子Ｄの調製
炭酸セリウム水和物３ｋｇを白金製容器に入れ、７００℃で、２時間、空気中で焼成することにより、黄白色の粉末を約１．５ｋｇ得た。この粉末の相同定をＸ線回折法で行い、酸化セリウムであることを確認した。焼成粉末の粒子径は３０〜１００μｍであった。
b. Preparation of Cerium Oxide Particle D 3 kg of cerium carbonate hydrate was put in a platinum container and calcined in the air at 700 ° C. for 2 hours to obtain about 1.5 kg of yellowish white powder. The powder was phase-identified by X-ray diffraction and confirmed to be cerium oxide. The particle diameter of the fired powder was 30 to 100 μm.
得られた焼成粉末の粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が３０ｎｍ、最大値が８０ｎｍであった。 When the particle surface of the obtained fired powder was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 30 nm, and the maximum value was 80 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕後の粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子の他に、１μｍから３μｍの大きな多結晶粒子と０．５から１μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ｄと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to small single crystal particles having a size equivalent to the crystallite diameter, large polycrystalline particles of 1 to 3 μm and polycrystalline particles of 0.5 to 1 μm were mixed. It was. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles D.
ｃ．酸化セリウム粒子Ｅの調製
炭酸セリウム水和物２ｋｇを白金製容器に入れ、６５０℃で、２時間、空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末の相同定をＸ線回折法で行ない、酸化セリウムであることを確認した。
c. Preparation of Cerium Oxide Particle E 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined in the air at 650 ° C. for 2 hours to obtain about 1 kg of yellowish white powder. The phase of this powder was identified by X-ray diffraction and confirmed to be cerium oxide.
得られた焼成粉末の粒子径は３０〜１００μｍであった。焼成粉末粒子の表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が１５ｎｍ、最大値が６０ｎｍであった。 The particle size of the obtained fired powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 15 nm, and the maximum value was 60 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕後の粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子の他に、１μｍから３μｍの大きな多結晶粒子と０．５から１μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ｅと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to small single crystal particles having a size equivalent to the crystallite diameter, large polycrystalline particles of 1 to 3 μm and polycrystalline particles of 0.5 to 1 μm were mixed. It was. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles E.
ｄ．酸化セリウム粒子Ｆの調製
炭酸セリウム水和物２ｋｇを白金製容器に入れ、６００℃で、２時間、空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末の相同定をＸ線回折法で行ない、酸化セリウムであることを確認した。焼成粉末の粒子径は３０〜１００μｍであった。
d. Preparation of Cerium Oxide Particle F 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined in the air at 600 ° C. for 2 hours to obtain about 1 kg of yellowish white powder. The phase of this powder was identified by X-ray diffraction and confirmed to be cerium oxide. The particle diameter of the fired powder was 30 to 100 μm.
得られた焼成粉末の粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム結晶子径を測定したところ、その分布の中央値が１０ｎｍ、最大値が４５ｎｍであった。 When the particle surface of the obtained fired powder was observed with a scanning electron microscope, a grain boundary of cerium oxide was observed. When the diameter of the cerium oxide crystallite surrounded by the grain boundary was measured, the median value of the distribution was 10 nm, and the maximum value was 45 nm.
次に、得られた焼成粉末１ｋｇを、ジェットミルを用いて乾式粉砕した。粉砕後の粒子について走査型電子顕微鏡で観察したところ、結晶子径と同等サイズの小さな単結晶粒子の他に、１μｍから３μｍの大きな多結晶粒子と０．５から１μｍの多結晶粒子が混在していた。多結晶粒子は、単結晶粒子の凝集体ではなかった。粉砕により得られた酸化セリウム粒子を、以下、酸化セリウム粒子Ｆと呼ぶ。 Next, 1 kg of the obtained fired powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to small single crystal particles having a size equivalent to the crystallite diameter, large polycrystalline particles of 1 to 3 μm and polycrystalline particles of 0.5 to 1 μm were mixed. It was. Polycrystalline particles were not aggregates of single crystal particles. The cerium oxide particles obtained by pulverization are hereinafter referred to as cerium oxide particles F.
（２）研磨剤の調製
ａ．研磨剤Ｃ，Ｄ，Ｅ，Ｆの調製
上記（１）で得られた酸化セリウム粒子Ｃ，Ｄ，Ｅ又はＦ１ｋｇと、ポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと、脱イオン水８９７７ｇとを混合し、攪拌しながら超音波を１０分間照射して、酸化セリウム粒子を分散させ、スラリーを得た。
(2) Preparation of abrasive a. Preparation of abrasives C, D, E, F 1 kg of the cerium oxide particles C, D, E or F obtained in (1) above, 23 g of an aqueous polyacrylate salt solution (40% by weight), 8977 g of deionized water, Were mixed and irradiated with ultrasonic waves for 10 minutes with stirring to disperse the cerium oxide particles to obtain a slurry.
得られたスラリーを２μｍフィルタでろ過をし、さらに脱イオン水を加えることにより、固形分３重量％研磨剤を得た。酸化セリウム粒子Ｃ，Ｄ，Ｅ又はＦから得られた研磨剤を、以下、それぞれ、研磨剤Ｃ，Ｄ，Ｅ又はＦと呼ぶ。研磨剤Ｃ，Ｄ，Ｅ又はＦのｐＨは、それぞれ８．０、８．１、８．４、８．４であった。 The obtained slurry was filtered with a 2 μm filter, and deionized water was further added to obtain an abrasive having a solid content of 3% by weight. The abrasive obtained from the cerium oxide particles C, D, E or F is hereinafter referred to as abrasive C, D, E or F, respectively. The pH of abrasive C, D, E or F was 8.0, 8.1, 8.4 and 8.4, respectively.
研磨剤中の粒子を走査型電子顕微鏡で観察するために、各研磨剤をそれぞれ適当な濃度に希釈した後乾燥させて、中に含まれる多結晶粒子径を測定したところ、酸化セリウム粒子Ｃを用いた研磨剤Ｃでは、中央値が８８２ｎｍ、最大値が１２６４ｎｍであった。また、酸化セリウム粒子Ｄを用いた研磨剤Ｄでは、中央値が８００ｎｍ、最大値が１４４０ｎｍであった。酸化セリウム粒子Ｅを用いた研磨剤Ｅでは、中央値が８３１ｎｍ、最大値が１５００ｎｍであった。酸化セリウム粒子Ｆを用いた研磨剤Ｆでは、中央値が８４０ｎｍ、最大値が１４６８ｎｍであった。 In order to observe the particles in the abrasive with a scanning electron microscope, each abrasive was diluted to an appropriate concentration and then dried, and the polycrystalline particle size contained therein was measured. The abrasive C used had a median value of 882 nm and a maximum value of 1264 nm. Moreover, in the abrasive | polishing agent D using the cerium oxide particle D, the median value was 800 nm and the maximum value was 1440 nm. In the abrasive E using the cerium oxide particles E, the median value was 831 nm and the maximum value was 1500 nm. In the abrasive F using the cerium oxide particles F, the median value was 840 nm and the maximum value was 1468 nm.
次に、研磨剤の分散性及び分散粒子の電荷を調べるため、研磨剤Ｃ，Ｄ，Ｅ又はＦのゼータ電位を、実施例１と同様にして調べたところ、いずれの研磨剤中の粒子もマイナスに荷電し、それぞれ−６４ｍＶ、−３５ｍＶ、−３８ｍＶ、−４１ｍＶと絶対値が大きく分散性が良好であることが確認された。 Next, in order to investigate the dispersibility of the abrasive and the charge of the dispersed particles, the zeta potential of the abrasive C, D, E or F was examined in the same manner as in Example 1. It was confirmed that it was negatively charged and had a large absolute value of -64 mV, -35 mV, -38 mV, and -41 mV, respectively, and good dispersibility.
ｂ．研磨剤Ｃ’，Ｄ’，Ｅ’，Ｆ’の調製
酸化セリウム粒子Ｃ，Ｄ，Ｅ又はＦ１ｋｇと、ポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと、脱イオン水８９７７ｇとを混合し、攪拌しながら超音波を１０分間照射して、酸化セリウム粒子を分散させ、スラリーを得た。
b. Preparation of abrasives C ′, D ′, E ′, F ′ Mix 1 kg of cerium oxide particles C, D, E or F, 23 g of ammonium polyacrylate aqueous solution (40% by weight) and 8977 g of deionized water, Ultrasonic waves were irradiated for 10 minutes while stirring to disperse the cerium oxide particles, thereby obtaining a slurry.
得られたスラリーを０．８μｍフィルタでろ過をし、さらに脱イオン水を加えることにより、固形分３重量％の研磨剤を得た。酸化セリウム粒子Ｃ，Ｄ，Ｅ又はＦから得られた研磨剤を、以下、それぞれ、研磨剤Ｃ’，Ｄ’，Ｅ’又はＦ’と呼ぶ。研磨剤Ｃ’，Ｄ’，Ｅ’又はＦ’のｐＨは、それぞれ８．０、８．１、８．４、８．４であった。 The obtained slurry was filtered through a 0.8 μm filter, and deionized water was further added to obtain an abrasive having a solid content of 3% by weight. The abrasive obtained from the cerium oxide particles C, D, E or F is hereinafter referred to as abrasive C ', D', E 'or F', respectively. The pH of the abrasive C ', D', E 'or F' was 8.0, 8.1, 8.4 and 8.4, respectively.
研磨剤中の粒子を走査型電子顕微鏡で観察するために、研磨剤Ｃ’，Ｄ’，Ｅ’又はＦ’をそれぞれ適当な濃度に希釈して乾燥させた後、含まれる多結晶粒子の粒径を測定したところ、酸化セリウム粒子Ｃを用いた研磨剤Ｃ’では、中央値が３９８ｎｍ、最大値が８９０ｎｍであった。また、酸化セリウム粒子Ｄを用いた研磨剤Ｄ’では、中央値が４０５ｎｍ、最大値が９２０ｎｍであった。酸化セリウム粒子Ｅを用いた研磨剤Ｅ’では、中央値が４１５ｎｍ、最大値が９９０ｎｍであった。酸化セリウム粒子Ｆを用いた研磨剤Ｆ’では、中央値が４５０ｎｍ、最大値が１０８０ｎｍであった。 In order to observe the particles in the abrasive with a scanning electron microscope, the abrasive C ′, D ′, E ′ or F ′ is diluted to an appropriate concentration and dried. When the diameter was measured, the abrasive C ′ using cerium oxide particles C had a median value of 398 nm and a maximum value of 890 nm. Further, in the abrasive D ′ using the cerium oxide particles D, the median value was 405 nm and the maximum value was 920 nm. In the abrasive E ′ using the cerium oxide particles E, the median value was 415 nm and the maximum value was 990 nm. In the abrasive F ′ using the cerium oxide particles F, the median value was 450 nm and the maximum value was 1080 nm.
次に、研磨剤中の粒子の分散性及び分散粒子の電荷を調べるため、実施例１と同様にして各研磨剤のゼータ電位を調べたところ、いずれの研磨剤の分散粒子もマイナスに荷電し、それぞれ、−５８ｍＶ、−５５ｍＶ、−４４ｍＶ、−４０ｍＶと絶対値が大きく分散性が良好であることが確認された。 Next, in order to investigate the dispersibility of the particles in the abrasive and the charge of the dispersed particles, the zeta potential of each abrasive was examined in the same manner as in Example 1. As a result, all the dispersed particles of the abrasive were negatively charged. It was confirmed that the absolute values were large, such as -58 mV, -55 mV, -44 mV, and -40 mV, respectively, and the dispersibility was good.
（３）絶縁膜層の研磨
研磨剤として、本実施例で調製した研磨剤Ｃ，Ｄ，Ｅ，Ｆ，Ｃ’，Ｄ’，Ｅ’又はＦ’を用いた他は、実施例１と同様にして、Ｓｉウエハ表面のＳｉＯ２絶縁膜を研磨し、洗浄・乾燥して、ＳｉＯ２絶縁膜の膜厚変化を測定したところ、研磨剤Ｃを用いた場合は７４０ｎｍ（研磨速度：３７０ｎｍ／分）、研磨剤Ｄを用いた場合は７３０ｎｍ（研磨速度：３６５ｎｍ／分）、研磨剤Ｅを用いた場合は７５０ｎｍ（研磨速度：３７５ｎｍ／分）、研磨剤Ｆを用いた場合は７２０ｎｍ（研磨速度：３６０ｎｍ／分）、研磨剤Ｃ’を用いた場合は７００ｎｍ（研磨速度：３５０ｎｍ／分）、研磨剤Ｄ’を用いた場合は６９０ｎｍ（研磨速度：３４５ｎｍ／分）、研磨剤Ｅ’を用いた場合は７１０ｎｍ（研磨速度：３５５ｎｍ／分）、研磨剤Ｆ’を用いた場合は７１０ｎｍ（研磨速度：３５５ｎｍ／分）の絶縁膜がそれぞれ削られ、いずれの研磨剤を用いた場合も、ウエハ全面に渡って均一の厚みになっていることがわかった。また、光学顕微鏡を用いて絶縁膜表面を観察したところ、いずれの場合も明確な傷は見られなかった。
(3) Polishing of insulating film layer The same as Example 1 except that the polishing agent C, D, E, F, C ′, D ′, E ′ or F ′ prepared in this example was used as the polishing agent. Then, the SiO 2 insulating film on the surface of the Si wafer was polished, washed and dried, and the change in thickness of the SiO 2 insulating film was measured. When the polishing agent C was used, 740 nm (polishing rate: 370 nm / min) ), 730 nm (polishing rate: 365 nm / min) when abrasive D is used, 750 nm (polishing rate: 375 nm / min) when abrasive E is used, 720 nm (polishing rate) when abrasive F is used : 360 nm / min), 700 nm (polishing rate: 350 nm / min) when abrasive C ′ is used, 690 nm (polishing rate: 345 nm / min) when abrasive D ′ is used, abrasive E ′ is used 710 nm (polishing rate: 355 nm / min) When the polishing agent F ′ is used, the insulating films of 710 nm (polishing rate: 355 nm / min) are respectively shaved, and even when any polishing agent is used, the thickness is uniform over the entire surface of the wafer. all right. Further, when the surface of the insulating film was observed using an optical microscope, no clear scratch was observed in any case.
＜比較例＞
気孔を有しないシリカが分散されたシリカスラリーを研磨剤として用い、実施例１，２と同様にして、Ｓｉウエハ表面にＴＥＯＳ−ＣＶＤ法により形成されたＳｉＯ２絶縁膜の研磨を行った。このスラリーのｐＨは１０．３であり、ＳｉＯ２粒子を１２．５重量％含んでいるものであった。また、研磨条件は実施例１，２と同一とした。
<Comparative example>
A silica slurry in which silica having no pores was dispersed was used as an abrasive, and the SiO 2 insulating film formed on the Si wafer surface by the TEOS-CVD method was polished in the same manner as in Examples 1 and 2 . The slurry had a pH of 10.3 and contained 12.5% by weight of SiO 2 particles. The polishing conditions were the same as in Examples 1 and 2.
研磨後の絶縁膜を観察したところ、研磨による傷は見られず、また均一に研磨がなされたが、２分間の研磨により１５０ｎｍ（研磨速度：７５ｎｍ／分）の絶縁膜層しか削れなかった。 When the insulating film after polishing was observed, scratches due to polishing were not found, and polishing was performed uniformly, but only 150 nm (polishing rate: 75 nm / min) of the insulating film layer was removed by polishing for 2 minutes.
上述のように、本発明によれば、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することが可能となる。 As described above, according to the present invention, it is possible to polish a surface to be polished such as an SiO 2 insulating film at a high speed without scratching.
Claims (31)
前記酸化セリウム粒子は２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含み、
前記結晶子径が１０〜６００ｎｍである研磨剤。 An abrasive containing a slurry in which cerium oxide particles are dispersed in a medium,
The cerium oxide particles include cerium oxide particles composed of two or more crystallites and having a grain boundary,
An abrasive having a crystallite diameter of 10 to 600 nm.
前記酸化セリウム粒子は２個以上の結晶子から構成され結晶粒界を有する酸化セリウム粒子を含み、
前記結晶子径が１０〜６００ｎｍであるスラリー。 A slurry in which cerium oxide particles are dispersed in a medium,
The cerium oxide particles include cerium oxide particles composed of two or more crystallites and having a grain boundary,
A slurry having a crystallite diameter of 10 to 600 nm.
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| Application Number | Priority Date | Filing Date | Title |
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| JP34924097A JPH11181403A (en) | 1997-12-18 | 1997-12-18 | Cerium oxide abrasive and grinding of substrate |
| JP1997349240 | 1997-12-18 | ||
| JP8304298 | 1998-03-30 | ||
| JP1998083042 | 1998-03-30 | ||
| JP8304398 | 1998-03-30 | ||
| JP1998083043 | 1998-03-30 | ||
| JP2006335086A JP4788585B2 (en) | 1997-12-18 | 2006-12-12 | Abrasive and slurry |
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| JP2003394020A Division JP2004153286A (en) | 1997-12-18 | 2003-11-25 | Abrasive |
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| JP2012056073A (en) * | 2010-09-13 | 2012-03-22 | Kumamoto Prefecture | Polishing agent |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0881218A (en) * | 1994-07-11 | 1996-03-26 | Nissan Chem Ind Ltd | Production of crystalline ceric oxide |
| JPH08134435A (en) * | 1994-11-07 | 1996-05-28 | Mitsui Mining & Smelting Co Ltd | Abrasive and method for polishing |
| JPH0982667A (en) * | 1995-09-20 | 1997-03-28 | Hitachi Ltd | Abrasive and polishing and flattening |
| JPH09270402A (en) * | 1996-03-29 | 1997-10-14 | Hitachi Chem Co Ltd | Cerium oxide abraisives and method of manufacturing substrate |
| JPH101376A (en) * | 1996-04-19 | 1998-01-06 | Tosoh Corp | Silica formed body and its production |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0881218A (en) * | 1994-07-11 | 1996-03-26 | Nissan Chem Ind Ltd | Production of crystalline ceric oxide |
| JPH08134435A (en) * | 1994-11-07 | 1996-05-28 | Mitsui Mining & Smelting Co Ltd | Abrasive and method for polishing |
| JPH0982667A (en) * | 1995-09-20 | 1997-03-28 | Hitachi Ltd | Abrasive and polishing and flattening |
| JPH09270402A (en) * | 1996-03-29 | 1997-10-14 | Hitachi Chem Co Ltd | Cerium oxide abraisives and method of manufacturing substrate |
| JPH101376A (en) * | 1996-04-19 | 1998-01-06 | Tosoh Corp | Silica formed body and its production |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012056073A (en) * | 2010-09-13 | 2012-03-22 | Kumamoto Prefecture | Polishing agent |
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