JP2004128511A - Cerium oxide polishing agent, semiconductor chip and semiconductor devices, those manufacturing methods, as well as method for polishing substrate - Google Patents
Cerium oxide polishing agent, semiconductor chip and semiconductor devices, those manufacturing methods, as well as method for polishing substrate Download PDFInfo
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本発明は、酸化セリウム研磨剤、酸化セリウム研磨剤の製造法、基板の研磨法、半導体チップの製造法、半導体チップ、半導体装置の製造法及び半導体装置に関する。 The present invention relates to a cerium oxide abrasive, a method for manufacturing a cerium oxide abrasive, a method for polishing a substrate, a method for manufacturing a semiconductor chip, a method for manufacturing a semiconductor chip, a semiconductor device, and a semiconductor device.
近年、超LSIの急激な高密度・高集積化が進み、アルミニウム配線の多層化及びその配線パターンの微細化に伴う最小加工線幅の低減が要求されている。そこで、これらのLSIに用いられる層間絶縁膜にはこの微細な配線間隔を空洞無く埋め、かつ、その表面を平坦にする平坦化技術が求められている。 In recent years, the rapid increase in density and integration of ultra LSI has been advanced, and there has been a demand for a reduction in the minimum processing line width due to the multilayering of aluminum wiring and the miniaturization of its wiring pattern. Therefore, there is a demand for a flattening technique for filling the fine wiring intervals without voids in the interlayer insulating film used for these LSIs and for flattening the surface.
一般に、この平坦化を必要とする層間絶縁膜は、プラズマCVD法及びECR−CVD法等の蒸着法、SOG法などの塗布法により形成されている。これらの内、SOG法は、アルコキシシランおよびアルキルアルコキシシランをアルコールなどの有機溶媒中で水及び触媒により加水分解して得られる塗布液を、スピンコート法により塗布後、加熱処理により硬化させることによって平坦化させる方法で、中でも、クラックの発生を抑制し厚膜形成を可能とするために有機成分(例えばアルキル基)を膜中に残した有機SOG膜が主に用いられている。この有機SOG膜は、硬化時の体積収縮が少ない、疎水性を示す、誘電率が低いなどの利点を有する。また、この有機SOG膜は局部的な平坦化には適応可能であるが、配線の疎密に由来する様なグローバルな平坦化には力不足である。 Generally, the interlayer insulating film that needs to be planarized is formed by an evaporation method such as a plasma CVD method and an ECR-CVD method, and a coating method such as an SOG method. Among these, the SOG method is a method in which a coating solution obtained by hydrolyzing an alkoxysilane and an alkylalkoxysilane in an organic solvent such as an alcohol with water and a catalyst is applied by a spin coating method, and then cured by a heat treatment. Among these methods, an organic SOG film in which an organic component (for example, an alkyl group) is left in the film is mainly used to suppress the occurrence of cracks and to form a thick film. This organic SOG film has advantages such as low volume shrinkage upon curing, hydrophobicity, and low dielectric constant. Although this organic SOG film can be applied to local flattening, it is insufficient for global flattening due to the density of wiring.
また、この層間絶縁膜形成材料として、絶縁性、接着性などに優れたものとしてケイ素を含まない有機高分子樹脂の適用も進められている。この有機高分子樹脂をアルコールなどの有機溶媒中に溶解させた塗布液をスピンコート法により塗布後、加熱処理等により絶縁膜を形成させるので、比較的容易に厚い膜を形成することができる。 Also, as the material for forming the interlayer insulating film, application of an organic polymer resin containing no silicon as being excellent in insulating properties and adhesiveness has been promoted. Since a coating solution obtained by dissolving the organic polymer resin in an organic solvent such as alcohol is applied by spin coating, an insulating film is formed by heat treatment or the like, so that a thick film can be formed relatively easily.
超LSIは高密度・高集積化のために多層配線化が進み、特にロジック系デバイスではすでに4層以上になり表面の段差が大きくなる傾向にある。一方、配線のパターンニングのために用いるレジストの焦点深度は、配線の微細化に伴って浅くなる傾向にあり、上記の表面の高段差化が問題視されてきている。この高段差化を解消させるためにグローバルな平坦化が求められてきている。その一方法として、従来からSiウエハーの研磨に使用されている、化学研磨作用と機械的研磨作用の複合効果を利用した化学機械的研磨(CMP:Chemical Mechanical Polishing)の適用が期待されている。 (4) Multilayer wiring has been advanced in VLSI for high density and high integration, and particularly in logic devices, the number of layers has already been increased to four or more, and the step on the surface tends to increase. On the other hand, the depth of focus of a resist used for wiring patterning tends to be shallower as the wiring becomes finer, and the above-mentioned step height on the surface has been regarded as a problem. Global flattening has been demanded in order to eliminate the high step. As one of the methods, application of chemical mechanical polishing (CMP), which is conventionally used for polishing a Si wafer and utilizes a combined effect of a chemical polishing action and a mechanical polishing action, is expected.
絶縁膜のうち、CVD法により形成された膜は、従来からSiウエハーの研磨に用いられているコロイダルシリカを分散させたスラリーを研磨剤として用いることにより比較的容易に研磨が可能である。しかし、このCVD法は、配線パターンの微細化に伴う高アスペクト比の溝に対する埋込み性は悪く、アスペクト比3程度が限界とされている。また、膜の低誘電率化を図るためにフッ素の導入等が試みられているが、導入したフッ素の脱離や膜の吸湿性の増加などの問題点がまだ解決されていない状況にある。 (4) Among the insulating films, a film formed by the CVD method can be relatively easily polished by using a slurry in which colloidal silica conventionally used for polishing a Si wafer is dispersed as an abrasive. However, in this CVD method, the embedding property in a groove having a high aspect ratio due to the miniaturization of the wiring pattern is poor, and the aspect ratio is limited to about 3. Attempts have been made to introduce fluorine in order to lower the dielectric constant of the film, but problems such as desorption of the introduced fluorine and an increase in the hygroscopicity of the film have not yet been solved.
一方、SOG法により形成された有機SOG膜は、高アスペクト比の溝に対する埋込み性は良好で、アスペクト比10以上でも可能とされている。また、膜の誘電率は3程度とそのままでも低く、膜形成のコストもCVD法よりも低く抑えることが可能である。しかし、上記コロイダルシリカを用いた研磨剤で研磨すると研磨傷が発生しやすく、これを防ぐために研磨条件を緩やかにすると研磨速度が極端に低下してしまう。さらに、同じ条件で研磨しても、有機SOG膜の研磨速度はCVD膜の場合と比較すると極めて低い値しか得られず、このままではコストが高くなってしまうので適用は困難である。そこで、この有機SOG膜を高速で研磨することが可能な研磨剤の開発が求められている。 On the other hand, the organic SOG film formed by the SOG method has a good embedding property in a groove having a high aspect ratio, and is possible even with an aspect ratio of 10 or more. Further, the dielectric constant of the film is as low as about 3 as it is, and the cost of film formation can be suppressed to be lower than that of the CVD method. However, polishing is liable to occur when polishing with an abrasive using the above-mentioned colloidal silica, and if the polishing conditions are moderated to prevent this, the polishing rate will be extremely reduced. Further, even if the polishing is performed under the same conditions, the polishing rate of the organic SOG film is extremely low as compared with the case of the CVD film, and the cost is increased if the polishing is performed as it is. Therefore, development of a polishing agent capable of polishing this organic SOG film at high speed is required.
また、有機高分子樹脂を用いた膜は、1回の塗布で10μm以上の厚い膜を形成することができるので、グローバルな平坦化に有望と考えられている。また、膜の誘電率は3程度とそのままでも低いが、フッ素を含んだ樹脂を用いれば更に低い誘電率が得られ、アクリレート系ポリマーを用いれば紫外線硬化等の熱を使用しない形成方法が可能である。しかし、この有機高分子樹脂の硬度がCVD膜及び有機SOG膜と比較すると極めて低いために、上記コロイダルシリカを用いた研磨剤で研磨すると研磨傷が発生してしまう。これを防ぐために研磨傷が発生しなくなるまで研磨条件を緩やかにすると、ほとんど研磨されなくなってしまう。そこで、この有機高分子樹脂を用いた膜を研磨傷の発生無く研磨することが可能な研磨剤の開発が求められている。 膜 In addition, a film using an organic polymer resin is considered to be promising for global planarization because a film having a thickness of 10 μm or more can be formed by one application. Although the dielectric constant of the film is as low as about 3 as it is, a lower dielectric constant can be obtained by using a resin containing fluorine, and a forming method that does not use heat such as ultraviolet curing can be obtained by using an acrylate polymer. is there. However, since the hardness of this organic polymer resin is extremely low as compared with the CVD film and the organic SOG film, polishing scratches occur when polishing is performed with the above-mentioned abrasive using colloidal silica. If the polishing conditions are reduced until polishing scratches are no longer generated to prevent this, almost no polishing will occur. Therefore, there is a demand for the development of a polishing agent that can polish a film using the organic polymer resin without generation of polishing scratches.
本発明は、グローバルな平坦化が可能で、かつ、微細な配線間の埋め込み性が良好で誘電率の低い有機SOG膜、有機高分子樹脂膜の絶縁膜を研磨するために好適な酸化セリウム研磨剤、酸化セリウム研磨剤の製造法、その酸化セリウム研磨剤を使用する基板の研磨法、その基板の研磨法を利用する半導体チップの製造法、半導体チップ、半導体装置の製造法及び半導体装置を提供するものである。 The present invention provides cerium oxide polishing suitable for polishing an insulating film such as an organic SOG film or an organic polymer resin film that can be globally planarized, has good embedding between fine wirings, and has a low dielectric constant. Provided are a polishing agent, a method for producing a cerium oxide abrasive, a method for polishing a substrate using the cerium oxide abrasive, a method for producing a semiconductor chip utilizing the method for polishing the substrate, a method for producing a semiconductor chip, a semiconductor device, and a semiconductor device. To do.
本発明では、水中に酸化セリウム粒子を分散させたスラリーを含む、所定の基板上に設けられた絶縁膜を研磨するための酸化セリウム研磨剤が提供される。このスラリは、水溶媒100重量部に対して、酸化セリウム粒子を10重量部以下分散させたものであることが望ましい。また、本発明では、水中に酸化セリウム粒子を分散させてスラリーを調製する工程を含む、酸化セリウム研磨剤の製造法が提供される。 According to the present invention, there is provided a cerium oxide abrasive for polishing an insulating film provided on a predetermined substrate, the slurry including a slurry in which cerium oxide particles are dispersed in water. This slurry is preferably one in which 10 parts by weight or less of cerium oxide particles are dispersed in 100 parts by weight of an aqueous solvent. Further, the present invention provides a method for producing a cerium oxide abrasive, which comprises a step of preparing a slurry by dispersing cerium oxide particles in water.
ここで、酸化セリウム粒子は、つぎの(1)〜(11)の少なくともいずれかであることが望ましい。
(1)水中に分散された3価の非水溶性セリウム化合物を酸化剤で酸化することによって得られる酸化セリウム粒子
(2)3価の水溶性セリウム化合物の水溶液から得られる非水溶性セリウム化合物を酸化剤で酸化することによって得られる酸化セリウム粒子
この(1)または(2)において、酸化剤は過酸化水素であることが望ましい。
(3)4価のセリウム化合物の水溶液を中性又はアルカリ性にして得られる酸化セリウム粒子
(4)比表面積が25m2/g以上である酸化セリウム粒子
(5)静置法により測定した見掛け密度が1.30g/ml以下である酸化セリウム粒子
(6)タップ法により測定した見掛け密度が1.60g/ml以下である酸化セリウム粒子
(7)粉末X線回折パターンの主ピークの半値幅が0.4°以上である酸化セリウム粒子
(8)透過型電子顕微鏡による観察で一次粒子径が10nm以下である一次粒子が全数の90%以上の酸化セリウム粒子
(9)一次粒子径が10nm以下である一次粒子が全数の90%以上であり一次粒子が凝集した二次粒子径が1μm以下である二次粒子が全数の90%以上の酸化セリウム粒子
(10)直径が1μm以下である二次粒子が全数の90%以上であり、二次粒子が120°より小さい角部を含まない輪郭を示す酸化セリウム粒子
(11)一次粒子のアスペクト比が2.0以下である粒子の数が全数の90%以上である酸化セリウム粒子
また、スラリーは分散剤を含むことが望ましい。この分散剤としては、例えば、水溶性有機高分子、水溶性陰イオン性界面活性剤、水溶性非イオン性界面活性剤、水溶性アミンから選ばれる少なくとも一種を用いることができる。なお、スラリーはアルカリ性であることが望ましく、そのpHは8〜12であることが特に望ましい。
Here, the cerium oxide particles are desirably at least one of the following (1) to (11).
(1) Cerium oxide particles obtained by oxidizing a trivalent water-insoluble cerium compound dispersed in water with an oxidizing agent (2) Non-water-soluble cerium compound obtained from an aqueous solution of a trivalent water-soluble cerium compound Cerium oxide particles obtained by oxidizing with an oxidizing agent In this (1) or (2), the oxidizing agent is preferably hydrogen peroxide.
(3) Cerium oxide particles obtained by making an aqueous solution of a tetravalent cerium compound neutral or alkaline. (4) Cerium oxide particles having a specific surface area of 25 m 2 / g or more. (5) Apparent density measured by a static method. Cerium oxide particles of 1.30 g / ml or less (6) Cerium oxide particles of apparent density measured by a tap method of 1.60 g / ml or less (7) FWHM of main peak of powder X-ray diffraction pattern is 0. Cerium oxide particles of 4 ° or more (8) 90% or more of the total number of primary particles whose primary particle diameter is 10 nm or less observed by transmission electron microscope (9) Primary particles whose primary particle diameter is 10 nm or less 90% or more of the total number of particles and 90% or more of the total number of cerium oxide particles (10) having a secondary particle diameter of 1 μm or less where the primary particles are aggregated are 1 μm or less. Is 90% or more of the total number of the cerium oxide particles (11) in which the secondary particles have a contour not including a corner portion smaller than 120 °. Cerium oxide particles whose number is 90% or more of the total number Also, the slurry desirably contains a dispersant. As the dispersant, for example, 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 can be used. Note that the slurry is desirably alkaline, and the pH is particularly desirably 8 to 12.
さらに、本発明では、所定の基板に絶縁膜を形成し、絶縁膜を上述の酸化セリウム研磨剤で研磨する工程を備える基板の研磨法が提供される。この研磨法は、半導体基板の絶縁層の研磨に特に適している。また、本発明では、所定の半導体基板に有機基を有する化合物を含む絶縁層を備える絶縁膜を形成し、前記有機基を有する化合物を含む絶縁層を、この酸化セリウム研磨剤で研磨する工程を備える半導体チップの製造法と、該方法により製造された半導体チップとが提供される。さらに、本発明では、この半導体チップを支持基板に搭載し、該半導体チップを封止材で封止する工程を有する半導体装置の製造法と、該方法により製造された半導体装置とが提供される。 Further, the present invention provides a method for polishing a substrate, the method including a step of forming an insulating film on a predetermined substrate and polishing the insulating film with the above-mentioned cerium oxide abrasive. This polishing method is particularly suitable for polishing an insulating layer of a semiconductor substrate. Further, in the present invention, a step of forming an insulating film including an insulating layer containing a compound having an organic group on a predetermined semiconductor substrate, and polishing the insulating layer containing the compound having an organic group with the cerium oxide abrasive. Provided are a method of manufacturing a semiconductor chip provided with the semiconductor chip, and a semiconductor chip manufactured by the method. Further, the present invention provides a method of manufacturing a semiconductor device including a step of mounting the semiconductor chip on a support substrate and sealing the semiconductor chip with a sealing material, and a semiconductor device manufactured by the method. .
なお、絶縁膜は単一の層でなくてもよく、2層以上の絶縁層によって構成されてもよい。この場合は、複数の絶縁層のうち、少なくとも一層を上述の酸化セリウム研磨剤で選択的に研磨する。 Note that the insulating film does not have to be a single layer and may be composed of two or more insulating layers. In this case, at least one of the plurality of insulating layers is selectively polished with the above-mentioned cerium oxide abrasive.
この複数の絶縁層によって構成される絶縁膜は、有機基を有する化合物を含む絶縁層を含むことが望ましい。この有機基を有する化合物を含む絶縁層としては、例えば、アルコキシシランおよびアルキルアルコキシシランを有機溶媒中で水及び触媒の存在下で加水分解して得られる塗布液を基板に塗布後加熱硬化させて得らたものがある。絶縁膜は、この加水分解生成物を加熱硬化させて得られた絶縁層と、SiO2からなる絶縁膜層とを備えることが望ましい。上述の酸化セリウム研磨剤は、この有機基を有する化合物を含む絶縁層を選択的に研磨することができる。 The insulating film composed of the plurality of insulating layers desirably includes an insulating layer containing a compound having an organic group. As the insulating layer containing the compound having an organic group, for example, a coating solution obtained by hydrolyzing an alkoxysilane and an alkylalkoxysilane in an organic solvent in the presence of water and a catalyst is applied to a substrate and then heated and cured. There is something I got. The insulating film preferably includes an insulating layer obtained by heating and curing the hydrolysis product and an insulating film layer made of SiO 2 . The above-mentioned cerium oxide abrasive can selectively polish the insulating layer containing the compound having the organic group.
なお、この有機基を有する化合物を含む絶縁層中のシロキサン結合に由来するSi原子数とアルキル基に由来するC原子数は
C原子数/(Si原子数+C原子数)≧ 0.1
の関係にあることが望ましい。
The number of Si atoms derived from the siloxane bond and the number of C atoms derived from the alkyl group in the insulating layer containing the compound having an organic group are represented by the following formula: C atoms / (Si atoms + C atoms) ≧ 0.1
It is desirable to have the relationship of
また、絶縁膜層として、ケイ素を含まない有機高分子樹脂膜層を用いることもできる。 有機 Alternatively, an organic polymer resin film layer containing no silicon can be used as the insulating film layer.
本発明では、絶縁膜が二以上の絶縁層を備える場合、第一の絶縁膜層に対する研磨速度の、第二の絶縁膜層の研磨速度に対する比が10以上である酸化セリウム研磨剤により絶縁膜を研磨する基板の研磨法が提供される。ここで、第一の絶縁膜層および第二の絶縁膜層は、例えば、それぞれ、有機基を有する化合物を含む絶縁層およびSiO2絶縁膜層である。 In the present invention, when the insulating film includes two or more insulating layers, the ratio of the polishing rate for the first insulating film layer to the polishing rate of the second insulating film layer is not less than 10 by using a cerium oxide abrasive. A method for polishing a substrate is provided. Here, the first insulating film layer and the second insulating film layer are, for example, an insulating layer containing a compound having an organic group and a SiO 2 insulating film layer, respectively.
なお、本発明の基板研磨法では、絶縁膜層を研磨した後、基板を、過酸化水素と硝酸との混合物、硫酸、炭酸アンモニウム、カルバミン酸アンモニウム及び炭酸水素アンモニウムから選ばれる少なくとも一種を含む液で洗浄する工程を設けることが望ましい。 In the substrate polishing method of the present invention, after polishing the insulating film layer, the substrate is treated with a mixture containing at least one selected from a mixture of hydrogen peroxide and nitric acid, sulfuric acid, ammonium carbonate, ammonium carbamate and ammonium hydrogen carbonate. It is desirable to provide a step of washing with.
一般に、酸化セリウムは、代表的な希土類鉱物であるバストネサイト、モザナイト等を分離精製して得られるセリウム化合物(水酸化物、炭酸塩、硫酸塩、シュウ酸塩等)を焼成することによって得られる。有機SOG膜を研磨する場合には、酸化セリウムの結晶性が高いと研磨速度が低下する傾向を示すことから、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作製される。また、半導体チップの研磨に用いるので不純物の混入を防ぐために特にアルカリ金属類及びハロゲン類の含有量は1ppm以下に抑えることが好ましい。 In general, cerium oxide is obtained by calcining cerium compounds (hydroxides, carbonates, sulfates, oxalates, etc.) obtained by separating and purifying typical rare earth minerals such as bastnaesite and mosanite. Can be When polishing an organic SOG film, the polishing rate tends to decrease when the crystallinity of cerium oxide is high. Therefore, the cerium oxide particles used in the present invention are produced without increasing the crystallinity. In addition, since it is used for polishing a semiconductor chip, the content of alkali metals and halogens is particularly preferably suppressed to 1 ppm or less in order to prevent contamination of impurities.
本発明に於いて、酸化セリウム粒子を作成する方法としては、
(1)3価のセリウム化合物の中で水に溶解しないセリウム化合物を出発材料とし、これを水中に分散後、酸化剤を滴下することによって固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を作製する方法、
(2)3価のセリウム化合物の中で水溶性のものを出発材料とし、これを溶解させた水溶液に炭酸水素アンモニウム等を添加して得られる非水溶性セリウム化合物(沈殿物)に酸化剤を滴下することによって固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を作製する方法、
(3)4価のセリウム塩を出発材料とし、これを溶解させた水溶液にアンモニア水を添加する等により水溶液を中性、アルカリ性にすることにより4価の酸化セリウム粒子を作製する方法
が好ましく使用される。
In the present invention, as a method for producing cerium oxide particles,
(1) Among the trivalent cerium compounds, a cerium compound which does not dissolve in water is used as a starting material, and after dispersing the starting material in water, an oxidizing agent is added dropwise to oxidize in a solid state to give a tetravalent cerium compound. A method for producing cerium oxide particles,
(2) A water-soluble trivalent cerium compound is used as a starting material, and an oxidizing agent is added to a water-insoluble cerium compound (precipitate) obtained by adding ammonium hydrogen carbonate or the like to an aqueous solution in which this is dissolved. A method of producing tetravalent cerium oxide particles by performing an oxidation treatment in a solid state by dropping,
(3) A method of preparing tetravalent cerium oxide particles by using a tetravalent cerium salt as a starting material and making the aqueous solution neutral or alkaline by, for example, adding aqueous ammonia to an aqueous solution in which this is dissolved is preferably used. Is done.
3価の非水溶性セリウム化合物としては、炭酸セリウム、水酸化セリウム、シュウ酸セリウム、酢酸セリウムなどの非水溶性セリウム塩が挙げれ、特に制限はない。これらの3価の非水溶性セリウム化合物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、ボールミルなどを用いることができる。特に、分散粒子を細かくした方が後で施す酸化処理が容易に行えるので、ボールミルによる分散処理を施すのが好ましい。3価の非水溶性セリウム化合物の濃度には特に制限は無いが、分散液の取り扱い易さから1〜30重量%の範囲が好ましい。この3価の非水溶性セリウム化合物の分散液に酸化剤を添加することによって、固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を得る。ここで用いる酸化剤としては、硝酸カリウム等の硝酸塩、過マンガン酸カリウム等の過マンガン酸塩、クロム酸カリウム等のクロム酸塩、過酸化水素、ハロゲン、オゾンなどが挙げられる。これらの中では、酸化処理に伴う不純物の混入を防ぐために、過酸化水素を用いることが好ましい。酸化剤の添加量は、3価の非水溶性セリウム化合物1モルに対して1モル以上が必要であり、酸化処理を完結させることから1モル〜10モルの範囲が好ましい。処理温度には特に制限は無いが、過酸化水素等の自己分解性の酸化剤を用いる場合には40℃以下で処理を開始することが好ましく、全量添加後、過剰な酸化剤を分解させるために80℃以上に加熱することが好ましい。酸化処理を施して得られた粒子の回収は、デカンテーション、ろ過、遠心分離などの通常の方法が用いられるが、効率良く短時間で分離することが可能な遠心分離が好ましい。この際に、溶液のpHが酸側にあると粒子の沈殿が極めて遅く、一般的な遠心分離機では固液分離が困難になってしまうので、アンモニアなどの金属イオンを含まないアルカリ性物質を添加して溶液のpHを8以上にしてから遠心分離を行うことが好ましい。また、不純物濃度を低下させるために、沈殿物の洗浄を繰り返すことも有効である。回収した沈殿物をそのまま酸化セリウム粒子として使用してもよいが、回収した沈殿物を乾燥機などで水分を除去するようにしても良い。乾燥温度には特に制限は無いが、420℃以上では酸化セリウム粒子の結晶性が著しく増加してしまうので、420℃以下のできるだけ低い温度で乾燥させることが好ましい。 The trivalent water-insoluble cerium compound includes, but is not particularly limited to, water-insoluble cerium salts such as cerium carbonate, cerium hydroxide, cerium oxalate, and cerium acetate. As a method of dispersing the trivalent water-insoluble cerium compound in water, a homogenizer, an ultrasonic disperser, a ball mill, or the like can be used in addition to the dispersion treatment using a normal stirrer. In particular, it is preferable to perform the dispersion treatment by a ball mill, because the oxidation treatment to be performed later can be easily performed by making the dispersed particles finer. The concentration of the trivalent water-insoluble cerium compound is not particularly limited, but is preferably in the range of 1 to 30% by weight from the viewpoint of easy handling of the dispersion. By adding an oxidizing agent to the dispersion of the trivalent water-insoluble cerium compound, the solid state is subjected to an oxidation treatment to obtain tetravalent cerium oxide particles. The oxidizing agent used here includes nitrates such as potassium nitrate, permanganates such as potassium permanganate, chromates such as potassium chromate, hydrogen peroxide, halogen, ozone, and the like. Among them, it is preferable to use hydrogen peroxide in order to prevent impurities from being mixed in with the oxidation treatment. The addition amount of the oxidizing agent is required to be 1 mol or more per 1 mol of the trivalent water-insoluble cerium compound, and is preferably in the range of 1 mol to 10 mol in order to complete the oxidation treatment. The treatment temperature is not particularly limited, but when using a self-decomposable oxidizing agent such as hydrogen peroxide, it is preferable to start the treatment at 40 ° C. or lower. Is preferably heated to 80 ° C. or higher. For the recovery of the particles obtained by performing the oxidation treatment, ordinary methods such as decantation, filtration, and centrifugation are used, but centrifugation that can efficiently separate the particles in a short time is preferable. At this time, if the pH of the solution is on the acid side, the precipitation of particles is extremely slow and solid-liquid separation becomes difficult with a general centrifuge, so an alkaline substance that does not contain metal ions such as ammonia is added. It is preferable to carry out centrifugation after adjusting the pH of the solution to 8 or more. It is also effective to repeat the washing of the precipitate to reduce the impurity concentration. Although the collected precipitate may be used as it is as cerium oxide particles, the collected precipitate may be used to remove moisture with a dryer or the like. The drying temperature is not particularly limited. However, since the crystallinity of the cerium oxide particles is significantly increased at 420 ° C. or higher, it is preferable to dry at 420 ° C. or lower as low as possible.
3価の水溶性セリウム化合物としては、硝酸セリウム、硫酸セリウム、塩化セリウムなどの水溶性セリウム塩が挙げられ、特に制限はない。これらを溶解させた水溶液中の3価の水溶性セリウム化合物の濃度には特に制限は無いが、沈殿物である非水溶性セリウム化合物生成後の懸濁液の取り扱い易さから1〜30重量%の範囲が好ましい。これらの水溶液に炭酸水素アンモニウムの水溶液等を添加すると白色沈殿(非水溶性セリウム化合物)を生じる。ここで、炭酸水素アンモニウムの濃度は、3価の水溶性セリウム化合物1モルに対して1.5モル以上が必要であり、反応を完結させることから1.5モル〜30モルの範囲が好ましい。この3価の水溶性セリウム化合物から得られた沈殿物(非水溶性セリウム化合物)の分散液に酸化剤を添加することによって、固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を得る。ここで用いる酸化剤としては、3価の非水溶性セリウム化合物の場合と同じものが使用できる。これらの中では、酸化処理に伴う不純物の混入を防ぐために、過酸化水素を用いることが好ましい。酸化剤の添加量は、3価の水溶性セリウム化合物1モルに対して1モル以上が必要であり、酸化処理を完結させることから1モル〜10モルの範囲が好ましい。処理温度には特に制限は無いが、過酸化水素等の自己分解性の酸化剤を用いる場合には40℃以下で処理を開始することが好ましく、全量添加後、過剰な酸化剤を分解させるために80℃以上に加熱することが好ましい。酸化処理を施して得られた粒子の回収は、デカンテーション、ろ過、遠心分離などの通常の方法が用いられるが、効率良く短時間で分離することが可能な遠心分離が好ましい。この際に、溶液のpHが酸側にあると粒子の沈殿が極めて遅く、一般的な遠心分離機では固液分離が困難になってしまうので、アンモニアなどの金属イオンを含まないアルカリ性物質を添加して溶液のpHを8以上にしてから遠心分離を行うことが好ましい。また、不純物含有量を低下させるために、沈殿物を繰り返し洗浄することも有効である。回収した沈殿物をそのまま酸化セリウム粒子として使用してもよいが、回収した沈殿物を乾燥機などで水分を除去するようにしても良い。乾燥温度には特に制限は無いが、420℃以上では酸化セリウム粒子の結晶性が著しく増加してしまうので、420℃以下のできるだけ低い温度で乾燥させることが好ましい。 The trivalent water-soluble cerium compound includes, but is not particularly limited to, water-soluble cerium salts such as cerium nitrate, cerium sulfate, and cerium chloride. The concentration of the trivalent water-soluble cerium compound in the aqueous solution in which these are dissolved is not particularly limited. Is preferable. When an aqueous solution of ammonium hydrogen carbonate or the like is added to these aqueous solutions, a white precipitate (a water-insoluble cerium compound) is produced. Here, the concentration of ammonium bicarbonate needs to be 1.5 mol or more per 1 mol of the trivalent water-soluble cerium compound, and is preferably in the range of 1.5 mol to 30 mol in order to complete the reaction. By adding an oxidizing agent to a dispersion of the precipitate (water-insoluble cerium compound) obtained from the trivalent water-soluble cerium compound, it is subjected to an oxidizing treatment in a solid state, whereby tetravalent cerium oxide particles are obtained. Get. The same oxidizing agent as used in the case of the trivalent water-insoluble cerium compound can be used here. Among them, it is preferable to use hydrogen peroxide in order to prevent impurities from being mixed in with the oxidation treatment. The addition amount of the oxidizing agent is required to be 1 mol or more per 1 mol of the water-soluble trivalent cerium compound, and is preferably in the range of 1 mol to 10 mol in order to complete the oxidation treatment. The treatment temperature is not particularly limited, but when using a self-decomposable oxidizing agent such as hydrogen peroxide, it is preferable to start the treatment at 40 ° C. or lower. Is preferably heated to 80 ° C. or higher. For the recovery of the particles obtained by performing the oxidation treatment, ordinary methods such as decantation, filtration, and centrifugation are used, but centrifugation that can efficiently separate the particles in a short time is preferable. At this time, if the pH of the solution is on the acid side, the precipitation of particles is extremely slow and solid-liquid separation becomes difficult with a general centrifuge, so an alkaline substance that does not contain metal ions such as ammonia is added. It is preferable to carry out centrifugation after adjusting the pH of the solution to 8 or more. It is also effective to repeatedly wash the precipitate to reduce the content of impurities. Although the collected precipitate may be used as it is as cerium oxide particles, the collected precipitate may be used to remove moisture with a dryer or the like. The drying temperature is not particularly limited. However, since the crystallinity of the cerium oxide particles is significantly increased at 420 ° C. or higher, it is preferable to dry at 420 ° C. or lower as low as possible.
4価のセリウム化合物としては、硫酸セリウム、硫酸アンモニウムセリウム、硝酸アンモニウムセリウムなどのセリウム塩が挙げられ、特に制限はない。これらを溶解させた水溶液中の4価のセリウム化合物の濃度には特に制限は無いが、沈殿物(酸化セリウム粒子)生成後の懸濁液の取り扱い易さから1〜30重量%の範囲が好ましい。これらの水溶液は酸性であるが、水溶液にアンモニア水を添加する等により水溶液を中性、アルカリ性にすると白色沈殿(酸化セリウム粒子)を生じる。ここで、アンモニア水の添加量は、懸濁液のpHが初めの酸性から中性を示すまで加える必要があり、中性を経てアルカリ性を示すまで若干過剰に添加することが好ましい。沈殿処理を施して得られた粒子の回収は、デカンテーション、ろ過、遠心分離などの通常の方法が用いられるが、効率良く短時間で分離することが可能な遠心分離が好ましい。また、不純物の含有量を低下させるために、沈殿物を繰り返し洗浄することも有効である。回収した沈殿物をそのまま酸化セリウム粒子として使用してもよいが、回収した沈殿物を乾燥機などで水分を除去するようにしても良い。乾燥温度には特に制限は無いが、420℃以上では酸化セリウム粒子の結晶性が著しく増加してしまうので、420℃以下のできるだけ低い温度で乾燥させることが好ましい。 Examples of the tetravalent cerium compound include cerium salts such as cerium sulfate, ammonium cerium sulfate, and ammonium cerium nitrate, and are not particularly limited. The concentration of the tetravalent cerium compound in the aqueous solution in which these are dissolved is not particularly limited, but is preferably in the range of 1 to 30% by weight from the viewpoint of easy handling of the suspension after the formation of the precipitate (cerium oxide particles). . These aqueous solutions are acidic, but when the aqueous solution is made neutral or alkaline by adding ammonia water to the aqueous solution, white precipitates (cerium oxide particles) are generated. Here, it is necessary to add the aqueous ammonia until the pH of the suspension is initially acidic to neutral, and it is preferable to add the aqueous ammonia in a slightly excessive manner until the suspension becomes neutral and alkaline. For the recovery of the particles obtained by performing the precipitation treatment, ordinary methods such as decantation, filtration, and centrifugation are used, but centrifugation that can efficiently separate the particles in a short time is preferable. It is also effective to repeatedly wash the precipitate to reduce the content of impurities. Although the collected precipitate may be used as it is as cerium oxide particles, the collected precipitate may be used to remove moisture with a dryer or the like. The drying temperature is not particularly limited. However, since the crystallinity of the cerium oxide particles is significantly increased at 420 ° C. or higher, it is preferable to dry at 420 ° C. or lower as low as possible.
本発明に於いては、以下の示す物性の酸化セリウム粒子が用いられる。
本発明に於いては、比表面積が25m2/g以上で好ましくは1,000m2/g以下、更に好ましくは50m2/g以上で500m2/g以下を有する酸化セリウム粒子が用いられる。比表面積が25m2/g未満の酸化セリウム粒子を水中に分散させたスラリーを用いると、その一次粒子径が大きくなるために研磨後の被研磨表面に傷が発生する場合がある。また、比表面積が1,000m2/gを越える酸化セリウム粒子を用いると、その研磨速度が極端に小さくなるために十分な研磨効果が得られにくい。ここで、比表面積の測定方法としては、窒素吸着法、窒素脱着法、水銀圧入法などが挙げられ、特に制限はないが、測定が簡便なことから窒素吸着法を用いることが好ましい。
In the present invention, cerium oxide particles having the following physical properties are used.
In the present invention, cerium oxide particles having a specific surface area of 25 m 2 / g or more, preferably 1,000 m 2 / g or less, more preferably 50 m 2 / g or more and 500 m 2 / g or less are used. When a slurry in which cerium oxide particles having a specific surface area of less than 25 m 2 / g are dispersed in water is used, the primary particle diameter becomes large, so that a polished surface may be scratched after polishing. If cerium oxide particles having a specific surface area of more than 1,000 m 2 / g are used, a sufficient polishing effect is hardly obtained because the polishing rate becomes extremely low. Here, examples of the method for measuring the specific surface area include a nitrogen adsorption method, a nitrogen desorption method, a mercury intrusion method, and the like. There is no particular limitation, but the nitrogen adsorption method is preferably used because the measurement is simple.
本発明に於いては、静置法により測定した見掛け密度が好ましくは0.80g/ml以上で1.30g/ml以下、更に好ましくは0.90g/ml以上1.20g/ml以下を有する酸化セリウム粒子が用いられる。見掛け密度が1.30g/mlを越える酸化セリウム粒子を水中に分散させたスラリーを用いると、その一次粒子径が大きくなるために研磨後の被研磨表面に傷が発生する場合がある。また、見掛け密度が0.80g/ml未満の酸化セリウム粒子を用いると、その研磨速度が極端に小さくなるために十分な研磨効果が得られない場合がある。 In the present invention, oxidation having an apparent density measured by a static method of preferably 0.80 g / ml or more and 1.30 g / ml or less, more preferably 0.90 g / ml or more and 1.20 g / ml or less. Cerium particles are used. When a slurry in which cerium oxide particles having an apparent density exceeding 1.30 g / ml are dispersed in water is used, the primary particle diameter becomes large, so that the surface to be polished after polishing may be damaged. In addition, when cerium oxide particles having an apparent density of less than 0.80 g / ml are used, a sufficient polishing effect may not be obtained because the polishing rate becomes extremely low.
ここで、見掛け密度の測定方法は、静的測定法と動的測定法があり特に制限は無いが、JIS K−5101に規定されている静置法が測定が簡便なことから好ましい。 Here, the method of measuring the apparent density includes a static measurement method and a dynamic measurement method, and there is no particular limitation. However, the static method specified in JIS K-5101 is preferable because the measurement is simple.
本発明に於いては、タップ法により測定した見掛け密度が好ましくは1.00g/ml以上で1.60g/ml以下、更に好ましくは1.05g/ml以上1.55g/ml以下を有する酸化セリウム粒子が用いられるを用いる。見掛け密度が1.6g/mlを越える酸化セリウム粒子を水中に分散させたスラリーを用いると、その一次粒子径が大きくなるために研磨後の被研磨表面に傷が発生する場合がある。また、見掛け密度が1.00g/ml未満の酸化セリウム粒子を用いると、その研磨速度が極端に小さくなるために十分な研磨効果が得られない場合がある。 In the present invention, cerium oxide having an apparent density measured by a tap method of preferably from 1.00 g / ml to 1.60 g / ml, more preferably from 1.05 g / ml to 1.55 g / ml. The particles used are used. When a slurry in which cerium oxide particles having an apparent density exceeding 1.6 g / ml are dispersed in water is used, the primary particle diameter becomes large, so that a polished surface may be damaged after polishing. In addition, when cerium oxide particles having an apparent density of less than 1.00 g / ml are used, a sufficient polishing effect may not be obtained because the polishing rate becomes extremely low.
ここで、見掛け密度の測定方法は、静的測定法と動的測定法があり特に制限は無いが、JIS K−5101に規定されているタップ法が測定が簡便なことから好ましい。 Here, the method of measuring the apparent density includes a static measurement method and a dynamic measurement method, and there is no particular limitation. However, the tap method specified in JIS K-5101 is preferable because the measurement is simple.
本発明に於いては、粉末X線回折パターンの主ピークの半値幅が好ましくは0.4°以上で5.0°以下、更に好ましくは0.5°以上で2.0°以下の値を有する酸化セリウム粒子が用いられる。この範囲では、有機SOG膜あるいは有機高分子樹脂膜の研磨速度がCVD膜(SiO2)よりも10倍以上大きい値を示すので、選択的な研磨に優れる。粉末X線回折パターンの主ピークの半値幅が0.4°未満の酸化セリウム粒子を水中に分散させたスラリーを用いると、その結晶性が向上するために研磨後の被研磨表面に傷が発生する場合がある。また、CVD膜の研磨速度が有機SOG膜あるいは有機高分子樹脂膜の場合と同程度まで上昇してしまうので、選択的な研磨ができにくくなる。一方、粉末X線回折パターンの主ピークの半値幅が5.0°より大きい酸化セリウム粒子を用いると、その研磨速度が極端に小さくなるために十分な研磨効果が得られにくい。 本発明に於いては、一次粒子径が10nm以下である一次粒子が全数の90%以上であり、一次粒子が凝集した二次粒子径が1μm以下である二次粒子が全数の90%以上である酸化セリウム粒子が用いられる。粒子径の測定方法には特に制限は無いが、一次粒子径は透過型電子顕微鏡観察で、また、二次粒子径は走査型電子顕微鏡観察又は粒度分布測定装置による測定を用いる方法が簡便で好ましい。この範囲では、粒子濃度が低くても良好な研磨速度が得られるので、スラリーの低コスト化が可能である。また、粒子濃度を低下できると、スラリーの粘度が低下するので、研磨装置へのスラリーの輸送が容易となり、輸送パイプ内での粒子の詰りなども低減できる。さらに、研磨パッド上に滴下したスラリーの拡散が容易になるので、ウエハー内の均一研磨が可能となる。その一次粒子径が10nmを越える大きい粒子が凝集した二次粒子が1μmを越える酸化セリウム粒子を水中に分散させたスラリーを用いると、研磨後の被研磨表面に傷が発生する場合がある。 In the present invention, the half width of the main peak of the powder X-ray diffraction pattern is preferably from 0.4 ° to 5.0 °, more preferably from 0.5 ° to 2.0 °. Cerium oxide particles are used. In this range, the polishing rate of the organic SOG film or the organic polymer resin film is 10 times or more higher than that of the CVD film (SiO 2 ), so that the selective polishing is excellent. When a slurry in which cerium oxide particles having a half width of a main peak of a powder X-ray diffraction pattern of less than 0.4 ° are dispersed in water is used, scratches are generated on a surface to be polished after polishing because the crystallinity is improved. May be. In addition, since the polishing rate of the CVD film increases to the same level as that of the organic SOG film or the organic polymer resin film, it becomes difficult to perform selective polishing. On the other hand, if cerium oxide particles having a half width of the main peak of the powder X-ray diffraction pattern larger than 5.0 ° are used, the polishing rate becomes extremely low, so that it is difficult to obtain a sufficient polishing effect. In the present invention, 90% or more of the total number of primary particles having a primary particle diameter of 10 nm or less, and 90% or more of the total number of secondary particles having a primary particle diameter of 1 μm or less. Certain cerium oxide particles are used. The method for measuring the particle diameter is not particularly limited, but the primary particle diameter is preferably observed by a transmission electron microscope, and the secondary particle diameter is preferably measured by a scanning electron microscope or a method using a particle size distribution measurement apparatus, which is simple and convenient. . In this range, a good polishing rate can be obtained even if the particle concentration is low, so that the cost of the slurry can be reduced. Further, when the particle concentration can be reduced, the viscosity of the slurry decreases, so that the slurry can be easily transported to the polishing apparatus, and clogging of particles in the transport pipe can be reduced. Further, since the slurry dropped on the polishing pad can be easily diffused, uniform polishing within the wafer can be performed. When a slurry in which cerium oxide particles having a primary particle diameter exceeding 10 nm and a secondary particle having a diameter of more than 1 nm are aggregated and dispersed in water is used, scratches may be generated on the surface to be polished after polishing.
本発明に於いては、一次粒子径が10nm以下である一次粒子が全数の90%以上であり、一次粒子が凝集した二次粒子径が1μm以下である二次粒子が全数の90%以上である酸化セリウム粒子が用いられる。粒子径の測定方法には特に制限は無いが、一次粒子径は透過型電子顕微鏡観察で、また、二次粒子径は走査型電子顕微鏡観察又は粒度分布測定装置による測定を用いる方法が簡便で好ましい。この範囲では、粒子濃度が低くても良好な研磨速度が得られるので、スラリーの低コスト化が可能である。また、粒子濃度を低下できると、スラリーの粘度が低下するので、研磨装置へのスラリーの輸送が容易となり、輸送パイプ内での粒子の詰りなども低減できる。さらに、研磨パッド上に滴下したスラリーの拡散が容易になるので、ウエハー内の均一研磨が可能となる。その一次粒子径が10nmを越える大きい粒子が凝集した二次粒子が1μmを越える酸化セリウム粒子を水中に分散させたスラリーを用いると、研磨後の被研磨表面に傷が発生する場合がある。さらに、上記と同様な研磨速度を得るためには、粒子濃度を増加させなければならないので、コスト高、粘度の上昇などの問題点が生じがちである。 In the present invention, 90% or more of the total number of primary particles having a primary particle diameter of 10 nm or less, and 90% or more of the total number of secondary particles having a primary particle diameter of 1 μm or less. Certain cerium oxide particles are used. The method for measuring the particle diameter is not particularly limited, but the primary particle diameter is preferably observed by a transmission electron microscope, and the secondary particle diameter is preferably measured by a scanning electron microscope or a method using a particle size distribution measurement apparatus, which is simple and convenient. . In this range, a good polishing rate can be obtained even if the particle concentration is low, so that the cost of the slurry can be reduced. Further, when the particle concentration can be reduced, the viscosity of the slurry decreases, so that the slurry can be easily transported to the polishing apparatus, and clogging of particles in the transport pipe can be reduced. Further, since the slurry dropped on the polishing pad can be easily diffused, uniform polishing within the wafer can be performed. When a slurry in which cerium oxide particles having a primary particle diameter exceeding 10 nm and a secondary particle having a diameter of more than 1 nm are aggregated and dispersed in water is used, scratches may be generated on the surface to be polished after polishing. Furthermore, in order to obtain the same polishing rate as described above, the particle concentration must be increased, so that problems such as high cost and increased viscosity tend to occur.
本発明に於いては、直径が1μm以下である二次粒子が全数の90%以上であり、二次粒子が120°より小さい角部を含まない輪郭を示す酸化セリウム粒子が用いられる。粒子径の測定方法には特に制限は無いが、走査型電子顕微鏡観察又は粒度分布測定装置による測定を用いる方法が簡便で好ましい。この範囲では、粒子濃度が低くても良好な研磨速度が得られるので、スラリーの低コスト化が可能である。また、粒子濃度を低下できると、スラリーの粘度が低下するので、研磨装置へのスラリーの輸送が容易となり、輸送パイプ内での粒子の詰りなども低減できる。さらに、研磨パッド上に滴下したスラリーの拡散が容易になるので、ウエハー内の均一研磨が可能となる。二次粒子径が1μmを越える酸化セリウム粒子を水中に分散させたスラリーを用いると、研磨後の被研磨表面に傷が発生する。さらに、上記と同様な研磨速度を得るためには、粒子濃度を増加させなければならないので、コスト高、粘度の上昇などの問題点が生じやすくなる。また、二次粒子径が1μm以下でも、その粒子の輪郭に120°より小さい角部があると、研磨後の被研磨面に傷が発生しやすくなる。 セ In the present invention, cerium oxide particles are used, in which the secondary particles having a diameter of 1 μm or less account for 90% or more of the total number and the secondary particles have a contour that does not include corners smaller than 120 °. The method for measuring the particle diameter is not particularly limited, but a method using observation with a scanning electron microscope or measurement with a particle size distribution measuring device is simple and preferable. In this range, a good polishing rate can be obtained even if the particle concentration is low, so that the cost of the slurry can be reduced. Further, when the particle concentration can be reduced, the viscosity of the slurry decreases, so that the slurry can be easily transported to the polishing apparatus, and clogging of particles in the transport pipe can be reduced. Further, since the slurry dropped on the polishing pad can be easily diffused, uniform polishing within the wafer can be performed. When a slurry in which cerium oxide particles having a secondary particle diameter exceeding 1 μm are dispersed in water is used, scratches are generated on the surface to be polished after polishing. Furthermore, in order to obtain the same polishing rate as described above, the particle concentration must be increased, so that problems such as high cost and increased viscosity are likely to occur. Further, even if the secondary particle diameter is 1 μm or less, if the contour of the particle has a corner portion smaller than 120 °, the surface to be polished after polishing is likely to be damaged.
本発明に於いては、一次粒子のアスペクト比が2.0以下である粒子の数が全数の90%以上である酸化セリウム粒子が用いられる。その一次粒子のアスペクト比が2.0を越える酸化セリウム粒子を水中に分散させたスラリーを用いると、研磨後の被研磨表面に傷が発生す場合があるる。ここで、アスペクト比は、透過型電子顕微鏡による観察で一次粒子の短径と長径を測定し、これらの比を算出することによって求める方法が簡便で好ましい。 セ In the present invention, cerium oxide particles in which the number of primary particles having an aspect ratio of 2.0 or less is 90% or more of the total number are used. If a slurry is used in which cerium oxide particles whose primary particles have an aspect ratio exceeding 2.0 are dispersed in water, scratches may be generated on the surface to be polished after polishing. Here, the method of measuring the minor axis and the major axis of the primary particles by observation with a transmission electron microscope and calculating the ratio thereof is simple and preferable.
以上のような物性の酸化セリウム粒子を作製する方法としては、例えば前述したような、
(1)3価のセリウム化合物の中で水に溶解しないセリウム化合物を出発材料とし、これを水中に分散後、酸化剤を滴下することによって固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を作製する方法、
(2)3価のセリウム化合物の中で水溶性のものを出発材料とし、これを溶解させた水溶液に炭酸水素アンモニウム等を添加して得られる非水溶性セリウム化合物(沈殿物)に酸化剤を滴下することによって固体状態のままで酸化処理を施すことにより4価の酸化セリウム粒子を作製する方法、
(3)4価のセリウム化合物を出発材料とし、これを溶解させた水溶液にアンモニア水を添加する等により水溶液を中性、アルカリ性にすることにより4価の酸化セリウム粒子を作製する方法など好ましく使用されるが、特に制限は無い。
As a method for producing cerium oxide particles having the above physical properties, for example, as described above,
(1) Among the trivalent cerium compounds, a cerium compound which does not dissolve in water is used as a starting material, and after dispersing the starting material in water, an oxidizing agent is added dropwise to oxidize in a solid state to give a tetravalent cerium compound. A method for producing cerium oxide particles,
(2) A water-soluble trivalent cerium compound is used as a starting material, and an oxidizing agent is added to a water-insoluble cerium compound (precipitate) obtained by adding ammonium hydrogen carbonate or the like to an aqueous solution in which this is dissolved. A method of producing tetravalent cerium oxide particles by performing an oxidation treatment in a solid state by dropping,
(3) A tetravalent cerium compound is used as a starting material, and a method of preparing tetravalent cerium oxide particles by making the aqueous solution neutral or alkaline by adding ammonia water to an aqueous solution in which the cerium compound is dissolved is preferably used. However, there is no particular limitation.
本発明の酸化セリウム粒子は、以上説明した次に示す特性の二以上を兼ね備えるものがより好ましい。
(1)比表面積が25m2/g以上。
(2)静置法により測定した見掛け密度が1.3g/ml以下。
(3)タップ法により測定した見掛け密度が1.6g/ml以下。
(4)粉末X線回折パターンの主ピークの半値幅が0.4°以上。
(5)透過型電子顕微鏡による観察で一次粒子径が20nm以下である一次粒子が全数の90%以上。
(6)一次粒子径が20nm以下である一次粒子が全数の90%以上であり、一次粒子が凝集した二次粒子径が1μm以下である二次粒子が全数の90%以上。
(7)直径が1μm以下である二次粒子が全数の90%以上であり、二次粒子が120°より小さい角部を含まない輪郭を示す。
(8)一次粒子のアスペクト比が2.0以下である粒子の数が全数の90%以上。
The cerium oxide particles of the present invention more preferably have two or more of the following characteristics described above.
(1) The specific surface area is 25 m 2 / g or more.
(2) The apparent density measured by a static method is 1.3 g / ml or less.
(3) The apparent density measured by the tap method is 1.6 g / ml or less.
(4) The half value width of the main peak of the powder X-ray diffraction pattern is 0.4 ° or more.
(5) 90% or more of the total number of primary particles having a primary particle diameter of 20 nm or less as observed by a transmission electron microscope.
(6) 90% or more of the total number of primary particles having a primary particle diameter of 20 nm or less, and 90% or more of the total number of secondary particles having a primary particle diameter of 1 μm or less.
(7) Secondary particles having a diameter of 1 μm or less account for 90% or more of the total number, and the secondary particles have a contour that does not include corners smaller than 120 °.
(8) The number of particles whose primary particles have an aspect ratio of 2.0 or less is 90% or more of the total number.
本発明における酸化セリウムスラリーは、水、上記の酸化セリウム粒子及び好ましくは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。ここで、酸化セリウム粒子の濃度には制限は無いが、懸濁液の取り扱い易さから1〜30重量%の範囲が好ましい。水溶媒100重量部に対して、酸化セリウム粒子を10重量部以下分散させてスラリーとすることが好ましい。 The cerium oxide slurry in the present invention is obtained by dispersing a composition comprising water, the above-mentioned cerium oxide particles, and preferably a dispersant. Here, the concentration of the cerium oxide particles is not limited, but is preferably in the range of 1 to 30% by weight from the viewpoint of easy handling of the suspension. It is preferable to disperse cerium oxide particles in an amount of 10 parts by weight or less with respect to 100 parts by weight of the aqueous solvent to form a slurry.
また分散剤としては、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、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、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、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、モノエタノールアミン、ジエタノールアミン等の水溶性アミン類などが挙げられる。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などから酸化セリウム粒子100重量部に対して0.1重量部〜100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。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、ボールミルなどを用いることができる。特に酸化セリウム粒子を1μm以下の微粒子として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、媒体撹拌式ミルなどの湿式分散機を用いることが好ましい。またスラリーはアルカリ性であることが好ましく、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。スラリーのpHが8〜12が好ましい。 As the dispersant, those containing no metal ions include acrylic acid polymers and their ammonium salts, methacrylic acid polymers and their ammonium salts, water-soluble organic polymers such as polyvinyl alcohol, ammonium lauryl sulfate, and polyoxyethylene. Water-soluble anionic surfactants such as ammonium lauryl ether sulfate; water-soluble nonionic surfactants such as polyoxyethylene lauryl ether and polyethylene glycol monostearate; and water-soluble amines such as monoethanolamine and diethanolamine. Can be The addition amount of these dispersants is preferably in the range of 0.1 to 100 parts by weight based on 100 parts by weight of cerium oxide particles from the viewpoint of the dispersibility and anti-settling properties of the particles in the slurry, and enhances the dispersing effect. For this purpose, it is preferable to put the particles into the disperser at the same time as the dispersion. As a method for dispersing the cerium oxide particles in water, a homogenizer, an ultrasonic disperser, a ball mill, or the like can be used in addition to the dispersion treatment using a normal stirrer. In particular, in order to disperse cerium oxide particles as fine particles of 1 μm or less, it is preferable to use a wet disperser such as a ball mill, a vibrating ball mill, a planetary ball mill, and a medium stirring mill. The slurry is preferably alkaline. If it is desired to increase the alkalinity of the slurry, an alkaline substance containing no metal ions, such as aqueous ammonia, can be added during or after the dispersion treatment. The pH of the slurry is preferably from 8 to 12.
本発明のスラリーには、本発明の酸化セリウム粒子以外に例えば希土類金属の酸化物、塩等か添加されていて良い。他の添加物の混入により分散性向上、化学反応促進、すべり特性向上、選択性向上等の特性向上が期待できる。他の添加物の混入量は固形分の50重量%以下が好ましい。 ス ラ リ ー In addition to the cerium oxide particles of the present invention, for example, oxides or salts of rare earth metals may be added to the slurry of the present invention. By mixing other additives, it is possible to expect improvement in characteristics such as improvement in dispersibility, promotion of chemical reaction, improvement in sliding characteristics, and improvement in selectivity. The content of other additives is preferably 50% by weight or less of the solid content.
本発明の酸化セリウム研磨材で研磨される有機基を有する化合物を含む絶縁層は、アルコキシシラン及びアルキルアルコキシシランをアルコールなどの有機溶媒中で水及び触媒により加水分解して得られる塗布液をスピンコート法などにより基板に塗布後、加熱処理により硬化させることにより製造される。 The insulating layer containing a compound having an organic group that is polished by the cerium oxide abrasive of the present invention is formed by spinning a coating liquid obtained by hydrolyzing alkoxysilane and alkylalkoxysilane in an organic solvent such as alcohol with water and a catalyst. It is manufactured by applying to a substrate by a coating method or the like, and then curing by heating.
ここで、アルコキシシランとしては、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシランなどのモノマ又はオリゴマなどが挙げられ、それぞれ単独で又は2種類以上組み合わせて用いることができる。また、アルキルアルコキシシランとしては、メチルトリメトキシシラン、フェニルトリメトキシシラン、ジメチルジメトキシシラン、ジフェニルジメトキシシラン、アミノプロピルトリメトキシシラン、3−グリシドキシプロピルトリメトキシシラン、3−メタクリロキシプロピルトリメトキシシラン、ビニルトリメトキシシランなどが挙げられ、これらはそれぞれ単独で又は2種類以上組み合わせて用いることができる。ここで、フルオロトリメトキシシラン、フルオロメチルジメトキシシランなどのアルコキシシラン、アルキルアルコキシシランのSiにフッ素が結合したもの、トリフルオロメチルトリメトキシシラントリフルオロメチルメチルジメトキシシランなどのアルキルアルコキシシランのアルキル基の少なくとも一部がフッ素化されたもの、アルコキシシラン、アルキルアルコキシシランのSiにフッ素が結合したものも用いることができる。これらはそれぞれ単独で又は2種類以上組み合わせて用いることができる。ここで、アルコシシランとアルキルアルコキシシランとの添加量の割合は、これらにより構成される絶縁膜中のシロキサン結合に由来するSi原子数とアルキル基に由来するC原子数が
C原子数/(Si原子数+C原子数)≧0.1
の関係にあることが好ましい。この割合が0.1より小さいと絶縁膜の形成時に膜中にクラックが発生し、膜の欠落、絶縁性の低下などの欠陥が生じてしまう。
Here, examples of the alkoxysilane include monomers or oligomers such as tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane, and these can be used alone or in combination of two or more. Examples of the alkylalkoxysilane include methyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane. And vinyltrimethoxysilane, and these can be used alone or in combination of two or more. Here, alkoxysilanes such as fluorotrimethoxysilane and fluoromethyldimethoxysilane, those in which fluorine is bonded to Si of an alkylalkoxysilane, and alkyl groups of an alkylalkoxysilane such as trifluoromethyltrimethoxysilanetrifluoromethylmethyldimethoxysilane At least a part thereof may be fluorinated, or alkoxysilane or alkylalkoxysilane in which fluorine is bonded to Si may be used. These can be used alone or in combination of two or more. Here, the ratio of the addition amount of the alkoxysilane and the alkylalkoxysilane is such that the number of Si atoms derived from the siloxane bond and the number of C atoms derived from the alkyl group in the insulating film formed of these are C atoms / (Si atom Number + C atom number) ≧ 0.1
It is preferable that the relationship If this ratio is smaller than 0.1, cracks occur in the film when the insulating film is formed, and defects such as lack of the film and deterioration of the insulating property occur.
有機溶媒としては、メチルアルコール、エチルアルコールなどの1価アルコール類及びそのエーテル又はエステル類、グリセリン、エチレングリコールなどの多価アルコール類及びそのエーテル又はエステル類、アセトン、メチエチルケトン、などのケトン類などが挙げられ、これらはそれぞれ単独で、又は2種類以上組み合わせて用いることができる。触媒としては、加水分解用として、塩酸、硝酸、リン酸などの無機酸、酢酸、マレイン酸などの有機酸、これらの酸無水物又は誘導体などの酸及び水酸化ナトリウム、アンモニア、メチルアミンなどのアルカリが挙げられる。 Examples of the organic solvent include monohydric alcohols such as methyl alcohol and ethyl alcohol and ethers or esters thereof, polyhydric alcohols such as glycerin and ethylene glycol and ethers or esters thereof, and ketones such as acetone and methyl ethyl ketone. And these can be used alone or in combination of two or more. As a catalyst, for hydrolysis, hydrochloric acid, nitric acid, inorganic acids such as phosphoric acid, acetic acid, organic acids such as maleic acid, acids such as acid anhydrides or derivatives thereof and sodium hydroxide, ammonia, methylamine and the like Alkali is mentioned.
ここで、水の添加量はアルコキシシラン及びアルキルアルコキシシランそれぞれのアルコキシ基100%に対して75%より少ない範囲が好ましく、75%以上ではアルコキシシラン及びアルキルアルコキシシランの加水分解が急激に生じるために塗布液がゲル化又は白濁してしまう。触媒の添加量は、アルコキシシラン及びアルキルアルコキシシラン100重量部に対して0.1重量部から5重量部が好ましく、0.1重量部未満ではアルコキシシラン及びアルキルアルコキシシランの加水分解が不十分なために塗布時に膜が形成されず、5重量部を越えると加水分解が急激に生じるために塗布液がゲル化してしまう。アルコキシシラン及びアルキルアルコキシシランは有機溶媒100重量部に対して1重量部から40重量部の範囲が好ましい。アルコキシシラン及びアルキルアルコキシシランが1重量部未満では塗布時に膜が形成されにくくなり、また、40重量部を超えると均一な膜が得にくくなる。高分子量化時の反応温度には、特に制限はないが、使用している有機溶媒の沸点以下が好ましく、得られる加水分解物の分子量を制御するために特に5℃から70℃が好ましい。加水分解時の反応時間には、特に制限はなく、所定の分子量に到達した時点で反応を終了する。この時の分子量の測定方法としては、特に制限はないが、液体クロマトグラフを用いた方法が簡便で好ましい。 Here, the addition amount of water is preferably in a range of less than 75% with respect to 100% of each alkoxy group of the alkoxysilane and the alkylalkoxysilane, and if it is 75% or more, hydrolysis of the alkoxysilane and the alkylalkoxysilane occurs rapidly. The coating solution gels or becomes cloudy. The addition amount of the catalyst is preferably 0.1 part by weight to 5 parts by weight based on 100 parts by weight of the alkoxysilane and the alkylalkoxysilane, and if less than 0.1 part by weight, the hydrolysis of the alkoxysilane and the alkylalkoxysilane is insufficient. Therefore, a film is not formed at the time of application, and when it exceeds 5 parts by weight, hydrolysis occurs rapidly, and the application liquid gels. The amount of the alkoxysilane and the alkylalkoxysilane is preferably in the range of 1 to 40 parts by weight based on 100 parts by weight of the organic solvent. If the amount of the alkoxysilane and the alkylalkoxysilane is less than 1 part by weight, it is difficult to form a film at the time of coating, and if it exceeds 40 parts by weight, it is difficult to obtain a uniform film. The reaction temperature at the time of increasing the molecular weight is not particularly limited, but is preferably equal to or lower than the boiling point of the organic solvent used, and particularly preferably 5 ° C to 70 ° C in order to control the molecular weight of the obtained hydrolyzate. The reaction time at the time of hydrolysis is not particularly limited, and the reaction is terminated when a predetermined molecular weight is reached. The method for measuring the molecular weight at this time is not particularly limited, but a method using a liquid chromatograph is simple and preferable.
これらの4成分から得られる絶縁層形成用材料は、次の様にして製造される。まず、有機溶媒中に所定量のアルコキシシラン及びアルキルアルコキシシランを分散させ、これに水及び触媒を混合してしばらく撹拌後、室温下又は加温下で高分子量化させることによって製造される。 絶 縁 The insulating layer forming material obtained from these four components is manufactured as follows. First, it is manufactured by dispersing a predetermined amount of alkoxysilane and alkylalkoxysilane in an organic solvent, mixing water and a catalyst, stirring for a while, and increasing the molecular weight at room temperature or under heating.
以上の方法により製造した絶縁層形成用材料を、所定の半導体基板、すなわち回路素子と配線パターンが形成された段階の半導体基板(予めIC回路等の所定の回路素子を形成させてその上にアルミニウム配線をパターニング済みの半導体基板)、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塗布して、乾燥により有機溶媒を除去後、100℃以上で加熱硬化させることにより絶縁層が形成される。図1において、11はIC回路等の所定の回路素子を形成させたSiウエハー、12はアルミニウム配線、13はCVD−SiO2膜(TEOS膜)、14は有機基を有する化合物を含む絶縁層である。絶縁層は配線の厚みより厚く、例えば配線の厚みの1.2倍以上の厚みで形成するのが好ましい。 The insulating layer forming material manufactured by the above method is applied to a predetermined semiconductor substrate, that is, a semiconductor substrate in which circuit elements and wiring patterns are formed (a predetermined circuit element such as an IC circuit is formed in advance, and aluminum is formed thereon). An insulating layer is formed by coating a semiconductor substrate such as a semiconductor substrate on which wiring has been patterned) and a semiconductor substrate at a stage where circuit elements have been formed, removing an organic solvent by drying, and heating and curing at 100 ° C. or more. Is done. In FIG. 1, reference numeral 11 denotes a Si wafer on which predetermined circuit elements such as an IC circuit are formed, 12 denotes an aluminum wiring, 13 denotes a CVD-SiO 2 film (TEOS film), and 14 denotes an insulating layer containing a compound having an organic group. is there. The insulating layer is preferably formed thicker than the thickness of the wiring, for example, at least 1.2 times the thickness of the wiring.
ここで、半導体基板としては、Siウエハー、GaAsウエハーなどが挙げられるが、特に制限は無い。また、塗布法としては、スピンコート法、スプレー法、ディップコート法などが挙げられ、特に制限はない。乾燥温度には、特に制限がないが、有機溶媒の揮散を促進するために100℃から300℃の範囲が好ましい。加熱硬化温度は、300℃以上で特に制限はないが、使用する基板によりその上限が有り、アルミニウム配線を施してあるものでは500℃以下が好ましい。加熱硬化時間には、特に制限はなく、硬化した膜の物性がほぼ平衡に到達した時点で加熱を終了する。この時の判定方法としては、特に制限はないが、膜の表面硬度、膜の厚さなどの測定が簡便で好ましい。加熱硬化時の雰囲気には、特に制限がないが、加熱中のアルキルアルコキシシラン中のアルキル基の脱離を低減させるために窒素、アルゴンなどの不活性ガスを導入することが好ましい。 Here, examples of the semiconductor substrate include a Si wafer and a GaAs wafer, but there is no particular limitation. Examples of the coating method include a spin coating method, a spraying method, and a dip coating method, and are not particularly limited. The drying temperature is not particularly limited, but is preferably in the range of 100 ° C to 300 ° C in order to promote the evaporation of the organic solvent. The heat curing temperature is not particularly limited to 300 ° C. or more, but there is an upper limit depending on the substrate used, and it is preferably 500 ° C. or less for aluminum wiring. There is no particular limitation on the heat curing time, and the heating is terminated when the physical properties of the cured film have almost reached equilibrium. The determination method at this time is not particularly limited, but measurement of the film surface hardness, the film thickness, and the like is simple and preferable. The atmosphere during the heat curing is not particularly limited, but it is preferable to introduce an inert gas such as nitrogen or argon in order to reduce the elimination of the alkyl group in the alkylalkoxysilane during the heating.
所定の半導体基板、すなわち回路素子と配線パターン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形成された絶縁層を上記酸化セリウムスラリーで研磨することによって、図2に示すように絶縁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。 Polishing an insulating layer formed on a predetermined semiconductor substrate, that is, a semiconductor substrate at a stage where circuit elements and wiring patterns are formed, a semiconductor substrate at a stage where circuit elements are formed, etc., with the cerium oxide slurry. As a result, as shown in FIG. 2, unevenness on the surface of the insulating layer is eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate.
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、一般的な不職布、発泡ポリウレタン、多孔質フッ素樹脂などが使用でき、特に制限は無い。また、研磨布にはスラリーが留まる様な溝加工を施すことが好ましい。研磨条件には制限は無いが、定盤の回転速度は半導体基板が飛び出さない様に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様に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。この時の供給量には制限は無いが、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く、単位面積当りの供給量が例えば18インチ定盤に対して25ml/min以上の割合が特に好ましい。この供給量が25ml/minより少ないと、十分な研磨速度が得られず、また、スラリーの拡散が不十分なために均一な研磨が得られない場合がある。さらに、機械的研磨の影響が大きくなるために、CVD膜の研磨速度が大きくなる傾向を示し、有機SOG膜との速度比で表される選択性低下するために、選択的な研磨が不可能になってしまう場合がある。 Here, as a polishing apparatus, a general polishing apparatus having a holder holding a semiconductor substrate and a platen on which a polishing cloth (pad) is attached (a motor or the like whose rotation speed can be changed is attached) is used. it can. As the polishing cloth, general nonwoven cloth, foamed polyurethane, porous fluororesin and the like can be used, and there is no particular limitation. Further, it is preferable that the polishing cloth is subjected to groove processing such that the slurry remains. The polishing conditions are not limited, but the rotation speed of the platen is preferably as low as 100 rpm or less so that the semiconductor substrate does not pop 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, the slurry is continuously supplied to the polishing cloth by a pump or the like. Although the supply amount at this time is not limited, it is preferable that the surface of the polishing cloth is always covered with the slurry, and the supply amount per unit area is, for example, 25 ml / min or more with respect to the 18-inch platen. Particularly preferred. If the supply amount is less than 25 ml / min, a sufficient polishing rate may not be obtained, and uniform polishing may not be obtained due to insufficient diffusion of the slurry. Further, because the influence of mechanical polishing increases, the polishing rate of the CVD film tends to increase, and the selectivity represented by the speed ratio with the organic SOG film decreases, so that selective polishing is impossible. In some cases.
研磨終了後の半導体基板は、流水中で良く洗浄後、表面に付着した酸化セリウム粒子を除去するために、
(a)過酸化水素及び
(b)硝酸、硫酸、炭酸アンモニウム、カルバミン酸アンモニウム及び炭酸水素アンモニウムから選ばれる少なくとも一種を含む液中に浸漬してから再度水洗し乾燥する。(a)及び(b)を含む液は二種以上を混合して使用しても良い。
After polishing, the semiconductor substrate is thoroughly washed in running water, and then to remove cerium oxide particles attached to the surface,
It is immersed in a solution containing (a) hydrogen peroxide and (b) at least one selected from nitric acid, sulfuric acid, ammonium carbonate, ammonium carbamate and ammonium hydrogen carbonate, washed again with water, and dried. The liquid containing (a) and (b) may be used as a mixture of two or more kinds.
ここで、浸漬時間には特に制限は無いが、酸化セリウム粒子の溶解によって生じる気泡が発生しなくなる時点で処理の終了を判断することができる。また、浸漬温度には特に制限は無いが、過酸化水素水などの自己分解性を示すものを用いる場合には、40℃以下で処理することが好ましい。水洗後は、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。 Here, although there is no particular limitation on the immersion time, the end of the treatment can be determined at the time when bubbles generated by dissolution of the cerium oxide particles are not generated. The immersion temperature is not particularly limited. However, when a material having self-decomposability such as aqueous hydrogen peroxide is used, the treatment is preferably performed at 40 ° C. or lower. After washing with water, it is preferable to use a spin dryer or the like to remove water droplets attached to the semiconductor substrate and then dry the semiconductor substrate.
この様にして平坦化された絶縁層の上に、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絶縁層を形成後、上記酸化セリウムスラリーを用いて研磨することによって、絶縁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。この工程を所定数繰り返すことにより半導体チップを製造する。 A second layer of aluminum wiring is formed on the flattened insulating layer, an insulating layer is formed again between the wirings and on the wiring by the above-described method, and then polished using the cerium oxide slurry. By doing so, unevenness on the surface of the insulating layer is eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate. A semiconductor chip is manufactured by repeating this process a predetermined number of times.
本発明の酸化セリウム研磨剤により、半導体基板等の基板に形成されたケイ素を含まない有機高分子樹脂層を研磨することができる。 ケ イ 素 With the cerium oxide abrasive of the present invention, a silicon-free organic polymer resin layer formed on a substrate such as a semiconductor substrate can be polished.
このようなケイ素を含有しない有機高分子樹脂としては、フェノール、エポキシ、不飽和ポリエステル、ポリエステル、ポリイミド、ポリアミドイミドなどの熱硬化性樹脂、ポリアミド、ポリウレタン、ポリエチレン、エチレン酢酸ビニル共重合体、ポリプロピレン、ポリスチレン、ABS樹脂、AS樹脂、ポリメチルメタクリレート、ポリ塩化ビニル、ポリビニルホルマリン、ポリ四フッ化エチレン、ポリ三フッ化塩化エチレンなどの熱可塑性樹脂などが挙げられる。これらの中で、ポリ四フッ化エチレン、ポリ三フッ化塩化エチレンなどのフッ素樹脂を用いると膜の低誘電率化に有効であり、ポリアミドイミド樹脂、ポリイミド樹脂などを用いると膜の耐熱性に有効であるが、特に制限は無い。 Examples of such a silicon-free organic polymer resin include phenol, epoxy, unsaturated polyester, polyester, polyimide, thermosetting resins such as polyamideimide, polyamide, polyurethane, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, Examples include thermoplastic resins such as polystyrene, ABS resin, AS resin, polymethyl methacrylate, polyvinyl chloride, polyvinyl formalin, polytetrafluoroethylene, and polytrifluoroethylene chloride. Of these, the use of a fluororesin such as polytetrafluoroethylene or polychlorotrifluoroethylene is effective in lowering the dielectric constant of the film, and the use of a polyamideimide resin or a polyimide resin reduces the heat resistance of the film. Although effective, there is no particular limitation.
これらのケイ素を含有しない有機高分子樹脂の絶縁膜形成用材料は次の様にして作製する。熱硬化性樹脂を用いる場合、それぞれのモノマー及び/又は低分子量のものをアルコールなどの上記に記載した有機溶媒中に溶解させることによって、絶縁層形成用の塗布液を作製する。ここで、硬化をより進めるために、一般に使用される硬化剤、促進剤、触媒などを併用することができる。また、熱可塑性樹脂を用いる場合、それぞれの樹脂をアルコールなどの上記に記載した有機溶媒中に溶解させることによって、絶縁層形成用の塗布液を作製する。有機高分子樹脂10重量部に対して有機溶媒は0重量部から900重量部の範囲が好ましい。有機溶媒が900重量部を超えると、塗布時に膜が形成されにくくなる。 These silicon-free organic polymer resin insulating film forming materials are prepared as follows. When a thermosetting resin is used, a coating liquid for forming an insulating layer is prepared by dissolving each monomer and / or low molecular weight resin in the above-mentioned organic solvent such as alcohol. Here, a commonly used curing agent, accelerator, catalyst and the like can be used in combination in order to further promote curing. When a thermoplastic resin is used, a coating liquid for forming an insulating layer is prepared by dissolving each resin in the above-mentioned organic solvent such as alcohol. The organic solvent preferably ranges from 0 parts by weight to 900 parts by weight based on 10 parts by weight of the organic polymer resin. When the amount of the organic solvent exceeds 900 parts by weight, it is difficult to form a film during coating.
本発明の酸化セリウム研磨剤により、半導体基板等の基板に形成された互いに異なる材料からなる2種類以上の絶縁層の少なくとも1種を選択的に研磨することができる。 (4) With the cerium oxide abrasive of the present invention, it is possible to selectively polish at least one of two or more types of insulating layers formed of different materials formed on a substrate such as a semiconductor substrate.
2種類以上の異なる絶縁層としては、アルコキシシラン及びアルキルアルコキシシランを有機溶媒中で水及び触媒の存在下で加水分解して得られる塗布液を基板に塗布後加熱硬化させて得らた絶縁層と、SiO2絶縁層と含むものが好ましく、本発明の酸化セリウム研磨剤により、前者の絶縁層を選択的に研磨することができる。 The insulating layer obtained by applying a coating solution obtained by hydrolyzing an alkoxysilane and an alkylalkoxysilane in an organic solvent in the presence of water and a catalyst to a substrate and then heating and curing the substrate is used as two or more different insulating layers. And a SiO 2 insulating layer, and the cerium oxide abrasive of the present invention can selectively polish the former insulating layer.
互いに異なる材料からなる2種類以上の絶縁層が形成される基板としては、SiO2絶縁膜等が形成された配線板、フォトマスク・レンズ・プリズム等の光学ガラス、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、磁気ヘッド等ある。 The substrate on which two or more types of insulating layers made of different materials are formed is made of a wiring board on which an SiO 2 insulating film or the like is formed, optical glass such as a photomask, a lens, a prism, etc., glass, and a crystalline material. Optical integrated circuits, optical switching elements, optical waveguides, optical fiber end faces, optical single crystals such as scintillators, solid laser single crystals, blue laser LED sapphire substrates, SiC, GaP, GaAs, etc. Semiconductor single crystal, a glass substrate for a magnetic disk, a magnetic head, and the like.
半導体基板等の基板に形成された互いに異なる材料からなる2種類以上の絶縁層の少なくとも1種を選択的に研磨する場合、第一の絶縁層(例えば有機基を有する化合物を有する絶縁層)に対する研磨速度と、第二の絶縁層(例えばSiO2絶縁層)に対する研磨速度との比が10以上である酸化セリウム研磨剤を使用すれば、選択研磨が良好に行える。 In the case where at least one of two or more insulating layers made of different materials formed on a substrate such as a semiconductor substrate is selectively polished, the first insulating layer (eg, an insulating layer having a compound having an organic group) may be used. If a cerium oxide abrasive having a ratio of the polishing rate to the polishing rate for the second insulating layer (for example, a SiO 2 insulating layer) of 10 or more is used, selective polishing can be favorably performed.
図3は、本発明の研磨剤で絶縁膜を研磨して製造された半導体チップを支持基板に搭載し、半導体チップを封止材で封止した半導体装置の一例を示すものである。半導体装置としては図3に示すようなLOC(lead on chip)タイプに限らず、COL(chip on lead)タイプでも、チップをダイパッドに搭載するタイプでも通常のものが製造される。封止材はエポキシ樹脂系の通常のものが使用できる。図3で、1はボンド材、2は本発明の研磨材で絶縁膜を研磨して製造された半導体チップ3はリードフレーム、4はワイヤ、5は封止材である。 FIG. 3 shows an example of a semiconductor device in which a semiconductor chip manufactured by polishing an insulating film with the abrasive of the present invention is mounted on a support substrate, and the semiconductor chip is sealed with a sealing material. The semiconductor device is not limited to the LOC (lead on chip) type as shown in FIG. 3, but a COL (chip on lead) type or a type in which a chip is mounted on a die pad is usually manufactured. An ordinary epoxy resin-based sealing material can be used. In FIG. 3, 1 is a bond material, 2 is a semiconductor chip manufactured by polishing an insulating film with the abrasive of the present invention, 3 is a lead frame, 4 is a wire, and 5 is a sealing material.
本発明の研磨剤により、有機SOG膜あるいは有機高分子樹脂膜等の絶縁膜を研磨傷を発生させること無く高速で研磨することが可能となる。 (4) The polishing agent of the present invention enables an insulating film such as an organic SOG film or an organic polymer resin film to be polished at high speed without causing polishing scratches.
本発明の基板の研磨法により、各層において基板全面に渡りその表面の段差がほとんど生じなくなるので、配線の微細化にも十分に対応でき、高密度・高集積化による多層配線化が実現できる。また、絶縁膜として有機SOG膜あるいは有機高分子樹脂膜を使用できるので、微細な配線間の埋め込み性及び低誘電率化も同時に図ることができる。 (4) Since the substrate polishing method of the present invention hardly causes a level difference on the surface of each layer over the entire surface of the substrate, it is possible to sufficiently cope with miniaturization of wirings and realize multilayer wiring by high density and high integration. Further, since an organic SOG film or an organic polymer resin film can be used as the insulating film, the burying property between fine wirings and the reduction of the dielectric constant can be simultaneously achieved.
以下、本発明の各種実施例について説明する。 Hereinafter, various embodiments of the present invention will be described.
実施例1
(酸化セリウム粒子の作製、1の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。
Example 1
(Preparation of cerium oxide particles, 1-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide.
(酸化セリウム粒子の作製、1の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。
(Preparation of cerium oxide particles, 1-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide.
(酸化セリウム粒子の作製、1の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して(pH10)、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。
(Preparation of cerium oxide particles, 1-3)
After 50 g of cerium ammonium nitrate was put in 500 g of deionized water and mixed well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring (pH 10), and the mixture was allowed to react at room temperature for 1 hour. A white precipitate was obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide.
(酸化セリウムスラリーの作製)
上記3種類の各酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の3種類の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
After dispersing 10 g of each of the above three types of cerium oxide powder in 100 g of deionized water, adding 1 g of ammonium polyacrylate thereto, and using a planetary ball mill (type P-5, manufactured by Flitsch) at 2800 rpm for 30 minutes By performing the dispersion treatment, three types of milky white cerium oxide slurries were obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーをスピンコータにセットし、テトラメトキシシラン(4モル)及びメチルトリメトキシシラン(1モル)をイソプロピルアルコール中で水及び硝酸を添加することにより加水分解して得られた塗布液5mlをウエハー上に塗布して、2,500rpmで30秒間回転後、250℃のホットプレートで1分間乾燥した。このウエハーを加熱炉中にセットし、450℃で30分間焼成することにより、絶縁層を形成させた。
(Formation of insulating layer)
An IC circuit is formed in advance, and a 4-inch Si wafer on which aluminum wiring is patterned is set on a spin coater, and tetramethoxysilane (4 mol) and methyltrimethoxysilane (1 mol) are mixed with water and nitric acid in isopropyl alcohol. Was applied on the wafer, and the solution was rotated at 2,500 rpm for 30 seconds and then dried on a hot plate at 250 ° C. for 1 minute. The wafer was set in a heating furnace and baked at 450 ° C. for 30 minutes to form an insulating layer.
(絶縁層の研磨)
保持する基板取り付け用の吸着パッドを貼り付けたホルダーに上記絶縁層を形成させたSiウエハーをセットし、多孔質フッ素樹脂製の研磨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)定盤上にSiウエハー面を下にしてホルダーを載せ、さらにその上に5Kgの重しを載せた。定盤上に上記3種類の酸化セリウムスラリーをそれぞれ滴下しながら、上盤を50rpmで4分間回転させ、絶縁膜を研磨した。研磨後、Siウエハーをホルダーから外して、流水中で良く洗浄後、硝酸を入れたビーカの中に浸し、このビーカを超音波洗浄機中にセットして10分間洗浄した。酸化セリウムの溶解に伴う発泡が収まったことを確認後、ビーカ中からSiウエハーを取りだし、スピンドライヤで水滴を除去後、120℃の乾燥機で10分間乾燥させた。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
The Si wafer on which the insulating layer was formed was set on the holder to which the suction pad for attaching the substrate to be attached was attached, and a polishing pad made of a porous fluororesin was attached (attaching a motor or the like capable of changing the number of rotations). The holder was placed on a surface plate with the Si wafer side down, and a 5 kg weight was placed thereon. While dropping the three types of cerium oxide slurries on the platen, the upper plate was rotated at 50 rpm for 4 minutes to polish the insulating film. After polishing, the Si wafer was removed from the holder, washed well in running water, immersed in a beaker containing nitric acid, and the beaker was set in an ultrasonic cleaner and washed for 10 minutes. After confirming that the bubbling accompanying the dissolution of cerium oxide had subsided, the Si wafer was taken out of the beaker, water droplets were removed with a spin drier, and dried with a dryer at 120 ° C. for 10 minutes. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例1
実施例と同様にして半導体基板に絶縁膜層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 1
An insulating film layer was formed on a semiconductor substrate in the same manner as in the example, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the step on the surface became extremely large. It was found that the insulation between the upper and lower layers was destroyed, and no further multilayering was possible.
また、上記絶縁膜層の研磨をアンモニア水溶媒系のコロイダルシリカスラリー(SS−225、Cabot社製商品名)を用いて試みたが、50rpmで10分間研磨しても約400Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 In addition, the polishing of the insulating film layer was attempted using an aqueous colloidal silica slurry (SS-225, trade name, manufactured by Cabot) using an ammonia water solvent. It has been found that it is extremely inefficient to flatten the entire surface of the wafer.
実施例2
(酸化セリウム粒子の作製、2の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法によりその比表面積を測定した結果、111m2/gを示した。
Example 2
(Preparation of cerium oxide particles, 2-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area was measured by a nitrogen adsorption method, and as a result, it was found to be 111 m 2 / g.
(酸化セリウム粒子の作製、2の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法によりその比表面積を測定した結果、112m2/gを示した。
(Preparation of cerium oxide particles, 2-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area was measured by a nitrogen adsorption method, and as a result, it was 112 m 2 / g.
(酸化セリウム粒子の作製、2の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法によりその比表面積を測定した結果、130m2/gを示した。
(Preparation of cerium oxide particles, 2-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area was measured by a nitrogen adsorption method, and as a result, it was 130 m 2 / g.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例2
実施例2と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 2
An insulating layer was formed in the same manner as in Example 2, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、上記絶縁層を試薬として市販されている酸化セリウム粒子(比表面積:4m2/g)を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約4100Åと同程度の絶縁膜が削られたが、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約1000Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 In addition, as a result of attempting to polish the insulating film with a slurry prepared in the same manner as above using commercially available cerium oxide particles (specific surface area: 4 m 2 / g) using the insulating layer as a reagent, about 4100 ° was obtained by polishing. Although the same amount of insulating film as that of the above was removed, it was confirmed that a large number of polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if polishing was performed at 50 rpm for 10 minutes, only about 1000 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例3
(酸化セリウム粒子の作製、3の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、静置法により測定した見かけ密度は1.07g/mlを示した。
Example 3
(Preparation of cerium oxide particles, 3-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The apparent density measured by the static method was 1.07 g / ml.
(酸化セリウム粒子の作製、3の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、静置法により測定した見かけ密度は1.11g/mlを示した。
(Preparation of cerium oxide particles, 3-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. The mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The apparent density measured by the static method was 1.11 g / ml.
(酸化セリウム粒子の作製、3の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、静置法により測定した見かけ密度は1.08g/mlを示した。
(Preparation of cerium oxide particles, 3-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The apparent density measured by the static method was 1.08 g / ml.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例3
実施例と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 3
An insulating layer was formed in the same manner as in the example, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. The properties were destroyed, and it was found that further multi-layering was not possible.
また、上記絶縁層を試薬として市販されている酸化セリウム粒子(静置法により測定した見かけ密度:1.33g/ml)を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約4100Åと同程度の絶縁膜が削られたが、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約1000Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 In addition, polishing of the insulating film was attempted with a slurry prepared in the same manner as above using commercially available cerium oxide particles (apparent density measured by a static method: 1.33 g / ml) using the insulating layer as a reagent. As a result, although the insulating film was cut by about 4100 ° by polishing, it was recognized that a large number of polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if polishing was performed at 50 rpm for 10 minutes, only about 1000 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例4
(酸化セリウム粒子の作製、4の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、タップ法によりその見掛け密度を測定した結果、1.43g/mlを示した。
Example 4
(Preparation of cerium oxide particles, 4-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, the apparent density was measured by the tap method and found to be 1.43 g / ml.
(酸化セリウム粒子の作製、4の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、タップ法によりその見掛け密度を測定した結果、1.52g/mlを示した。
(Preparation of cerium oxide particles, 4-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. The mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The apparent density was measured by the tap method, and as a result, it was found to be 1.52 g / ml.
(酸化セリウム粒子の作製、4の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、タップ法によりその見掛け密度を測定した結果、1.49g/mlを示した。
(Preparation of cerium oxide particles, 4-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. Moreover, the apparent density was measured by the tap method, and as a result, it was 1.49 g / ml.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例4
実施例4と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 4
An insulating layer was formed in the same manner as in Example 4, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、上記絶縁層を試薬としてタップ法によりその見掛け密度を測定した結果、1.67g/mlを示した市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約4100Åと同程度の絶縁膜が削られたが、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約1000Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 The apparent density of the insulating film was measured by a tap method using the insulating layer as a reagent. As a result, a slurry prepared in the same manner as described above using commercially available cerium oxide particles showing 1.67 g / ml was used to form the insulating film. As a result of the polishing, it was found that the insulating film was polished to the extent of about 4100 °, but a large number of polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if polishing was performed at 50 rpm for 10 minutes, only about 1000 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例5
(酸化セリウム粒子の作製、5の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、その主ピークの半値幅を測定した結果、1.38°を示した。
Example 5
(Preparation of cerium oxide particles, 5-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, the half-width of the main peak was measured and found to be 1.38 °.
(酸化セリウム粒子の作製、5の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、その主ピークの半値幅を測定した結果、1.30°を示した。
(Preparation of cerium oxide particles, 5-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, as a result of measuring the half width of the main peak, it showed 1.30 °.
(酸化セリウム粒子の作製、5の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、その主ピークの半値幅を測定した結果、1.44°を示した。
(Preparation of cerium oxide particles, 5-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, as a result of measuring the half width of the main peak, it was found to be 1.44 °.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
また、同じ条件でCVD膜(SiO2)の研磨を試みた結果、約200Åしか研磨されておらず、有機SOG膜の研磨速度との比は約20となり、有機SOG膜を選択的に研磨することが可能であることが認められた。 In addition, as a result of attempting to polish the CVD film (SiO 2 ) under the same conditions, only about 200 ° was polished, and the ratio to the polishing rate of the organic SOG film was about 20, and the organic SOG film was selectively polished. It was recognized that it was possible.
比較例5
実施例5と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 5
An insulating layer was formed in the same manner as in Example 5, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the step on the surface became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、上粉末X線回折パターンの主ピークの半値幅を測定した結果0.25°を示した試薬として市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、有機SOG膜は約4100Åと同程度研磨されたが、CVD膜も約4000Å研磨されてしまったので、有機SOG膜を選択的に研磨することは不可能であることが認められた。また、両者の場合とも、研磨後の表面に研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約1000Åしか削れなくなり、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 Also, the half-width of the main peak of the upper powder X-ray diffraction pattern was measured. As a result, a slurry prepared in the same manner as described above using cerium oxide particles commercially available as a reagent showing 0.25 ° As a result of polishing, the organic SOG film was polished to about 4100 °, but the CVD film was also polished to about 4000 °. Therefore, it was recognized that it was impossible to selectively polish the organic SOG film. Was done. In both cases, it was recognized that polishing scratches occurred on the polished surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if polishing was performed at 50 rpm for 10 minutes, only about 1000 mm could be removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例6
(酸化セリウム粒子の作製、6の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約5〜10nmを示した。
Example 6
(Preparation of cerium oxide particles, 6-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was found to be about 5 to 10 nm.
(酸化セリウム粒子の作製、6の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約2〜5nmを示した。
(Preparation of cerium oxide particles, 6-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. Further, the primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was about 2 to 5 nm.
(酸化セリウム粒子の作製、6の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約5〜10nmを示した。
(Preparation of cerium oxide particles, 6-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was found to be about 5 to 10 nm.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例6
実施例6と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 6
An insulating layer was formed in the same manner as in Example 6, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約50nmを示した試薬として市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約2000Åしか削られず、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約500Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 The primary particle diameter was measured by observation with a transmission electron microscope. As a result, the insulating film was polished with a slurry prepared in the same manner as described above using cerium oxide particles which are commercially available as a reagent showing about 50 nm. As a result, only about 2000 mm was polished by polishing, and it was recognized that many polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if it was polished at 50 rpm for 10 minutes, only about 500 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例7
(酸化セリウム粒子の作製、7の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約5〜10nmを示した。さらに、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果、約0.2μmを示した。
Example 7
(Production of cerium oxide particles, 7-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was found to be about 5 to 10 nm. Furthermore, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it was found to be about 0.2 μm.
(酸化セリウム粒子の作製、7の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約2〜5nmを示した。さらに、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果、約0.2〜0.3μmを示した。
(Production of cerium oxide particles, 7-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. Further, the primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was about 2 to 5 nm. Furthermore, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it was found to be about 0.2 to 0.3 μm.
(酸化セリウム粒子の作製、7の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約5〜10nmを示した。さらに、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果、約0.2μmを示した。
(Preparation of cerium oxide particles, 7-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The primary particle diameter was measured by observation with a transmission electron microscope, and as a result, it was found to be about 5 to 10 nm. Furthermore, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it was found to be about 0.2 μm.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例7
実施例7と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 7
An insulating layer was formed in the same manner as in Example 7, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、透過型電子顕微鏡での観察よりその一次粒子径を測定した結果、約50nmを示し、また、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果約5.0μmを示した試薬として市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約2000Åしか削られず、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約500Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 Further, the primary particle diameter was measured by observation with a transmission electron microscope to be about 50 nm, and the secondary particle diameter was observed to be about 5.0 μm by observation with a scanning electron microscope. As a result of attempting to polish the insulating film with a slurry prepared in the same manner as above using commercially available cerium oxide particles as a reagent, only about 2000 mm was polished by polishing, and many polishing scratches were generated on the surface. It was recognized that. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if it was polished at 50 rpm for 10 minutes, only about 500 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例8
(酸化セリウム粒子の作製、8の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、走査型電子顕微鏡での観察よりその二次粒子径を測定した結果、約0.2μmを示した。さらに、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
Example 8
(Preparation of cerium oxide particles, 8-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The secondary particle diameter was measured by observation with a scanning electron microscope. As a result, it was found to be about 0.2 μm. Further, it was recognized that the contour of the secondary particles had almost no corners and showed a smooth curve.
(酸化セリウム粒子の作製、8の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果、約0.2〜0.3μmを示した。さらに、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
(Preparation of cerium oxide particles, 8-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. Further, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it was found to be about 0.2 to 0.3 μm. Further, it was recognized that the contour of the secondary particles had almost no corners and showed a smooth curve.
(酸化セリウム粒子の作製、8の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果、約0.2μmを示した。さらに、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
(Production of cerium oxide particles, 8-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it was found to be about 0.2 μm. Further, it was recognized that the contour of the secondary particles had almost no corners and showed a smooth curve.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例8
実施例8と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 8
An insulating layer was formed in the same manner as in Example 8, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the step on the surface became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、走査型電子顕微鏡での観察によりその二次粒子径を測定した結果約1.0μmを示し、60〜110°の角部を含んだ輪郭を示す、試薬として市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約2100Åしか削られず、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約500Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 In addition, as a result of measuring the secondary particle diameter by observation with a scanning electron microscope, it shows about 1.0 μm, shows a contour including a corner of 60 to 110 °, and sells cerium oxide particles commercially available as a reagent. An attempt was made to polish the insulating film with the slurry prepared in the same manner as above, and as a result, only about 2100 mm was polished by polishing, and it was recognized that a large number of polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if it was polished at 50 rpm for 10 minutes, only about 500 mm was removed, and the entire surface of the Si wafer was flattened. Turned out to be extremely inefficient.
実施例9
(酸化セリウム粒子の作製、9の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子のアスペクト比を算出した結果、1.1を示した。
Example 9
(Production of cerium oxide particles, 9-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, as a result of calculating the aspect ratio of the primary particles from observation with a transmission electron microscope, the ratio was 1.1.
(酸化セリウム粒子の作製、9の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子のアスペクト比を算出した結果、1.4を示した。
(Preparation of cerium oxide particles, 9-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. In addition, as a result of calculating the aspect ratio of the primary particles from observation with a transmission electron microscope, it was found to be 1.4.
(酸化セリウム粒子の作製、9の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、透過型電子顕微鏡での観察よりその一次粒子のアスペクト比を算出した結果、1.2を示した。
(Preparation of cerium oxide particles, 9-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. Further, as a result of calculating the aspect ratio of the primary particle from observation with a transmission electron microscope, 1.2 was shown.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末10gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
10 g of the above cerium oxide powder is dispersed in 100 g of deionized water, 1 g of ammonium polyacrylate is added thereto, and then subjected to a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). Thereby, a milky white cerium oxide slurry was obtained. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
比較例9
実施例9と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 9
An insulating layer was formed in the same manner as in Example 9, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、透過型電子顕微鏡での観察よりその一次粒子のアスペクト比が3.0を示した試薬として市販されている酸化セリウム粒子を用いて上記と同様にして作製したスラリーで上記絶縁膜の研磨を試みた結果、研磨により約4000Åとほぼ同じ量が削られたが、その表面には多数の研磨傷が発生していることが認められた。そこで、ホルダーに乗せる重しを5kgから1kgに減少させると、研磨傷の発生は見られなくなったが、50rpmで10分間研磨しても約500Åしか削れなくなり、、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。 The polishing of the insulating film was carried out using a slurry prepared in the same manner as above using cerium oxide particles which are commercially available as a reagent whose primary particles showed an aspect ratio of 3.0 as determined by observation with a transmission electron microscope. As a result of the trial, it was found that the polishing removed about the same amount as about 4000 °, but that many polishing scratches were generated on the surface. Therefore, when the weight placed on the holder was reduced from 5 kg to 1 kg, the occurrence of polishing scratches was no longer observed. However, even if polishing was performed at 50 rpm for 10 minutes, only about 500 mm could be removed, and the entire surface of the Si wafer was flattened. Was found to be extremely inefficient.
実施例10
(酸化セリウム粒子の作製、10の1)
炭酸セリウム50gを脱イオン水450g中に添加後、遊星ボールミルを用いて2800rpmで15分間分散処理を施すことによって、白色の炭酸セリウムスラリーを得た。このスラリーに撹拌をしながら過酸化水素水(約35%)29.2gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末30gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法により測定した比表面積は111m2/gを示し、静置法により測定した見掛け密度は1.07g/mlを示し、タップ法により測定した見掛け密度は1.43g/mlを示し、粉末X線回折パターンの主ピークの半値幅は1.38°を示し、透過型電子顕微鏡での観察より測定した一次粒子径は約5〜10nmを示し、走査型電子顕微鏡での観察より測定した二次粒子径は約0.2μmを示し、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
Example 10
(Production of cerium oxide particles, 10-1)
After adding 50 g of cerium carbonate to 450 g of deionized water, a white cerium carbonate slurry was obtained by performing a dispersion treatment at 2800 rpm for 15 minutes using a planetary ball mill. 29.2 g of aqueous hydrogen peroxide (about 35%) was added dropwise to the slurry while stirring, the reaction was allowed to proceed for 1 hour while stirring was continued, and then the temperature was raised to 90 ° C. using a water bath. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 30 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area measured by the nitrogen adsorption method was 111 m 2 / g, the apparent density measured by the stationary method was 1.07 g / ml, and the apparent density measured by the tap method was 1.43 g / ml. The half value width of the main peak of the powder X-ray diffraction pattern was 1.38 °, the primary particle size was about 5 to 10 nm as measured by observation with a transmission electron microscope, and was measured by observation with a scanning electron microscope. The diameter of the secondary particles thus obtained was about 0.2 μm, and it was confirmed that the contour of the secondary particles had almost no corners and showed a smooth curve.
(酸化セリウム粒子の作製、10の2)
硝酸セリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながら炭酸水素アンモニウム75gを蒸留水400gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離した。この白色沈殿物を再度脱イオン水500g中に入れて良く分散後、過酸化水素水(約35%)60.9gを滴下し、さらに撹拌を続けながら1時間反応を進めてから、ウォーターバスを用いて90℃まで昇温させた。90℃で1時間撹拌後、室温まで冷却し、遠心分離機による固液分離後、120℃の乾燥機で24時間乾燥させることにより白色粉末20gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法により測定した比表面積は112m2/gを示し、静置法により測定した見掛け密度は1.11g/mlを示し、タップ法により測定した見掛け密度は1.52g/mlを示し、粉末X線回折パターンの主ピークの半値幅は1.30°を示し、透過型電子顕微鏡での観察より測定した一次粒子径は約2〜5nmを示し、走査型電子顕微鏡での観察により測定した二次粒子径は約0.2〜0.3μmを示し、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
(Production of cerium oxide particles, 10-2)
50 g of cerium nitrate was placed in 500 g of deionized water, mixed well, and then, while stirring, an aqueous solution obtained by dissolving 75 g of ammonium hydrogen carbonate in 400 g of distilled water was added dropwise. Got. This white precipitate was subjected to solid-liquid separation by treating with a centrifuge at 3000 rpm for 10 minutes. The white precipitate was again placed in 500 g of deionized water, dispersed well, and 60.9 g of hydrogen peroxide (about 35%) was added dropwise. The reaction was continued for 1 hour while stirring was continued. And heated to 90 ° C. After stirring at 90 ° C. for 1 hour, the mixture was cooled to room temperature, solid-liquid separated by a centrifugal separator, and dried with a dryer at 120 ° C. for 24 hours to obtain 20 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area measured by the nitrogen adsorption method was 112 m 2 / g, the apparent density measured by the stationary method was 1.11 g / ml, and the apparent density measured by the tap method was 1.52 g / ml. The half value width of the main peak of the powder X-ray diffraction pattern is 1.30 °, the primary particle size measured by observation with a transmission electron microscope is about 2 to 5 nm, and measured by observation with a scanning electron microscope. The obtained secondary particle diameter was about 0.2 to 0.3 μm, and it was recognized that the contour of the secondary particle had almost no corners and showed a smooth curve.
(酸化セリウム粒子の作製、10の3)
硝酸アンモニウムセリウム50gを脱イオン水500g中に入れて良く混合後、撹拌を続けながらアンモニア水27gを蒸留水500gに溶解させた水溶液を滴下して、そのまま室温下で1時間反応させることにより白色沈殿を得た。遠心分離機を用いて3000rpm、10分間処理することによりこの白色沈殿物を固液分離し後、120℃の乾燥機で24時間乾燥させることにより白色粉末15gを得た。この白色粉末のX線回折パターンを測定した結果、酸化セリウムであることが同定された。また、窒素吸着法により測定した比表面積は130m2/gを示し、静置法により測定した見掛け密度は1.08g/mlを示し、タップ法により測定した見掛け密度は1.49g/mlを示し、粉末X線回折パターンの主ピークの半値幅は1.44°を示し、透過型電子顕微鏡での観察より測定した一次粒子径は約5〜10nmを示し、走査型電子顕微鏡での観察により測定した二次粒子径は約0.2μmを示し、その二次粒子の輪郭にはほとんど角部が無く、滑らかな曲線を示していることが認められた。
(Production of cerium oxide particles, 10-3)
After adding 50 g of cerium ammonium nitrate to 500 g of deionized water and mixing well, an aqueous solution in which 27 g of ammonia water was dissolved in 500 g of distilled water was added dropwise with stirring, and the mixture was allowed to react at room temperature for 1 hour to form a white precipitate. Obtained. This white precipitate was subjected to solid-liquid separation by treating at 3000 rpm for 10 minutes using a centrifugal separator, and then dried in a dryer at 120 ° C. for 24 hours to obtain 15 g of a white powder. As a result of measuring the X-ray diffraction pattern of this white powder, it was identified to be cerium oxide. The specific surface area measured by the nitrogen adsorption method was 130 m 2 / g, the apparent density measured by the stationary method was 1.08 g / ml, and the apparent density measured by the tap method was 1.49 g / ml. , The half value width of the main peak of the powder X-ray diffraction pattern was 1.44 °, the primary particle size measured by observation with a transmission electron microscope was about 5 to 10 nm, and was measured by observation with a scanning electron microscope. The diameter of the secondary particles thus obtained was about 0.2 μm, and it was confirmed that the contour of the secondary particles had almost no corners and showed a smooth curve.
(酸化セリウムスラリーの作製)
上記酸化セリウム粉末2.5gを脱イオン水100g中に分散して、これにポリアクリル酸アンモニウム塩1gを添加後、遊星ボールミル(Pー5型、フリッチェ製)を用いて2800rpmで30分間分散処理を施すことによって、乳白色の酸化セリウムスラリーを得た。コールターカウンタ(N−4型、日科機製)を用いてこのスラリーの粒度分布を測定した結果、平均粒子径が176nmと小さく、その分布は単分散で比較的分布も狭いことが分かった。
(Preparation of cerium oxide slurry)
2.5 g of the above-mentioned cerium oxide powder was dispersed in 100 g of deionized water, and 1 g of ammonium polyacrylate was added thereto, followed by a dispersion treatment at 2800 rpm for 30 minutes using a planetary ball mill (P-5, manufactured by Flitsch). To give a milky white cerium oxide slurry. As a result of measuring the particle size distribution of this slurry using a Coulter counter (Type N-4, manufactured by Nikkaki Co., Ltd.), it was found that the average particle size was as small as 176 nm, and the distribution was monodisperse and relatively narrow.
(絶縁層の形成)
予めIC回路を形成させてその上にアルミニウム配線をパターニング済みの4インチSiウエハーに実施例1と同様にして絶縁層を形成させた。
(Formation of insulating layer)
An IC layer was formed in advance, and an insulating layer was formed on a 4-inch Si wafer on which aluminum wiring had been patterned in the same manner as in Example 1.
(絶縁層の研磨)
上記酸化セリウムスラリーを使用し、実施例1と同様にして上記絶縁層を形成させたSiウエハーの絶縁膜を研磨した。自動エリプソメータを用いて研磨前後の膜厚変化を測定した結果、この研磨により約4000Åの絶縁層が削られ、Siウエハー全面に渡ってほぼ均一の厚みになっていることが分った。また、Siウエハーをカットし、その断面をSEMで観察した結果、幅0.1μmで深さ1.0μmの配線間の溝部分にも空洞等の欠陥が見られず、十分な埋め込み性を示すことが分った。この工程を6回繰り返して6層配線を形成させたが、その断面のSEM観察から、各層においてSi基板全面に渡りその表面の段差がほとんど認められず、配線パターンも精度良く切れていることが分った。
(Polishing of insulating layer)
Using the cerium oxide slurry, the insulating film of the Si wafer on which the insulating layer was formed was polished in the same manner as in Example 1. As a result of measuring the change in film thickness before and after polishing using an automatic ellipsometer, it was found that this polishing removed the insulating layer of about 4000 ° and became almost uniform over the entire surface of the Si wafer. In addition, as a result of cutting the Si wafer and observing the cross section thereof with a SEM, no defect such as a cavity was found in the groove portion between the wirings having a width of 0.1 μm and a depth of 1.0 μm, and sufficient embeddability was exhibited. I understood that. This process was repeated six times to form a six-layer wiring. From the SEM observation of the cross-section, it was found that there was almost no level difference on the entire surface of the Si substrate in each layer, and the wiring pattern was cut with high precision. I understand.
また、同じ条件でCVD膜(SiO2)の研磨を試みた結果、約200Åしか研磨されておらず、有機SOG膜の研磨速度との比は約1/20となり、有機SOG膜を選択的に研磨することが可能であることが認められた。 In addition, as a result of attempting to polish the CVD film (SiO 2 ) under the same conditions, only about 200 ° was polished, and the ratio to the polishing rate of the organic SOG film was about 1/20. It has been found that polishing is possible.
比較例10
実施例10と同様にして絶縁層を形成し、酸化セリウムスラリーを用いた研磨をせずに多層配線の形成を試みたが、3層以上になると表面の段差が極めて大きくなるために上下層間の絶縁性が破壊され、これ以上の多層化はできないことが分った。
Comparative Example 10
An insulating layer was formed in the same manner as in Example 10, and an attempt was made to form a multilayer wiring without polishing using a cerium oxide slurry. However, when three or more layers were formed, the surface step became extremely large. It was found that the insulation property was destroyed, and no further multilayering was possible.
また、上記絶縁層の研磨をアンモニア水溶媒系のコロイダルシリカスラリー(SS−225、Cabot社製商品名)を用いて試みたが、50rpmで10分間研磨しても約400Åしか削れず、Siウエハー全面に渡って平坦にするには極めて効率が悪いことが分った。同じ条件でCVD膜の研磨を試みた結果、約400Åが研磨され、有機SOG膜の研磨速度との比が1しか得られないので、有機SOG膜を選択的に研磨することは不可能であることが分かった。 Further, the polishing of the insulating layer was attempted using an aqueous colloidal silica slurry (SS-225, trade name, manufactured by Cabot) using an aqueous ammonia solvent. However, even if it was polished at 50 rpm for 10 minutes, only about 400 mm was polished. It has been found that it is extremely inefficient to flatten the entire surface. As a result of attempting to polish the CVD film under the same conditions, about 400 ° is polished, and only a ratio of 1 to the polishing rate of the organic SOG film is obtained. Therefore, it is impossible to selectively polish the organic SOG film. I found out.
1・・・ボンド材、2・・・半導体チップ、3・・・リードフレーム、4・・・ワイヤ、5・・・封止材、11・・・IC回路等の所定の回路素子を形成させたSiウエハー、12・・・アルミニウム配線、13・・・CVD−SiO2膜(TEOS膜)、14・・・有機基を有する化合物を含む絶縁層。
DESCRIPTION OF SYMBOLS 1 ... Bond material, 2 ... Semiconductor chip, 3 ... Lead frame, 4 ... Wire, 5 ... Sealing material, 11 ... Form predetermined circuit elements such as IC circuits Si wafer, 12 ... aluminum wire, 13 ... CVD-SiO 2 film (TEOS film), an insulating layer containing a compound having a 14 ... organic groups.
Claims (36)
C原子数/(Si原子数+C原子数)≧0.1
の関係にある請求項23記載の基板の研磨法。 The number of Si atoms derived from the siloxane bond and the number of C atoms derived from the alkyl group in the insulating layer containing the compound having an organic group are: C atoms / (Si atoms + C atoms) ≧ 0.1
24. The method of polishing a substrate according to claim 23, wherein:
アルコキシシラン及びアルキルアルコキシシランを有機溶媒中で水及び触媒の存在下で加水分解して得られる塗布液を基板に塗布後加熱硬化させて得らた有機基を含有した絶縁膜層と、
SiO2絶縁膜層とを含み、
前記有機基を有する化合物を含む絶縁層を選択的に研磨する請求項26記載の基板の研磨法。 The insulating film,
An insulating film layer containing an organic group obtained by applying a coating solution obtained by hydrolyzing an alkoxysilane and an alkylalkoxysilane in an organic solvent in the presence of water and a catalyst and then heating and curing the coating solution on a substrate,
A SiO 2 insulating film layer,
The method for polishing a substrate according to claim 26, wherein the insulating layer containing the compound having an organic group is selectively polished.
(a)過酸化水素
(b)硝酸、硫酸、炭酸アンモニウム、カルバミン酸アンモニウム及び炭酸水素アンモニウムのうちから選ばれる少なくとも一種 The method for polishing a substrate according to any one of claims 20 to 29, comprising a step of washing the substrate with a liquid containing the following (a) and (b) after polishing the insulating film layer.
(A) hydrogen peroxide (b) at least one selected from nitric acid, sulfuric acid, ammonium carbonate, ammonium carbamate and ammonium hydrogen carbonate
C原子数/(Si原子数+C原子数)≧0.1
の関係にある請求項32記載の半導体チップの製造法。 The number of Si atoms derived from the siloxane bond and the number of C atoms derived from the alkyl group in the insulating layer containing the compound having an organic group are: C atoms / (Si atoms + C atoms) ≧ 0.1
33. The method for manufacturing a semiconductor chip according to claim 32, wherein:
A semiconductor device manufactured by the method according to claim 35.
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JP2009290188A (en) * | 2008-04-30 | 2009-12-10 | Hitachi Chem Co Ltd | Abrasive powder and polishing method |
JP2014058422A (en) * | 2012-09-18 | 2014-04-03 | Kyushu Univ | Method for producing cerium oxide particle |
JP2015187069A (en) * | 2014-03-13 | 2015-10-29 | 第一稀元素化学工業株式会社 | Cerium-containing solution and production method thereof |
JPWO2018179062A1 (en) * | 2017-03-27 | 2019-12-26 | 日立化成株式会社 | Polishing liquid, polishing liquid set, additive liquid and polishing method |
CN114933301A (en) * | 2022-05-18 | 2022-08-23 | 广东东岛新能源股份有限公司 | Long-life artificial graphite negative electrode material for energy storage and preparation method and application thereof |
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JP2009290188A (en) * | 2008-04-30 | 2009-12-10 | Hitachi Chem Co Ltd | Abrasive powder and polishing method |
JP2014058422A (en) * | 2012-09-18 | 2014-04-03 | Kyushu Univ | Method for producing cerium oxide particle |
JP2015187069A (en) * | 2014-03-13 | 2015-10-29 | 第一稀元素化学工業株式会社 | Cerium-containing solution and production method thereof |
JPWO2018179062A1 (en) * | 2017-03-27 | 2019-12-26 | 日立化成株式会社 | Polishing liquid, polishing liquid set, additive liquid and polishing method |
CN114933301A (en) * | 2022-05-18 | 2022-08-23 | 广东东岛新能源股份有限公司 | Long-life artificial graphite negative electrode material for energy storage and preparation method and application thereof |
CN115368826A (en) * | 2022-08-26 | 2022-11-22 | 江南大学 | Polishing solution based on sphere-like cerium oxide abrasive particles and preparation method and application thereof |
CN115368826B (en) * | 2022-08-26 | 2023-08-25 | 江南大学 | Polishing solution based on spheroidal cerium oxide abrasive particles, and preparation method and application thereof |
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