JP2002270545A - Polishing liquid for conductor and polishing method using the same - Google Patents
Polishing liquid for conductor and polishing method using the sameInfo
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- JP2002270545A JP2002270545A JP2001063905A JP2001063905A JP2002270545A JP 2002270545 A JP2002270545 A JP 2002270545A JP 2001063905 A JP2001063905 A JP 2001063905A JP 2001063905 A JP2001063905 A JP 2001063905A JP 2002270545 A JP2002270545 A JP 2002270545A
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- conductor
- polishing
- acid
- tantalum
- copper
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、特に半導体デバイ
スの配線形成工程の研磨に使用される導体用研磨液及び
これを用いた研磨方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing slurry for a conductor used for polishing in a wiring forming step of a semiconductor device, and a polishing method using the same.
【０００２】[0002]
【従来の技術】近年、半導体集積回路（以下ＬＳＩと記
す）の高集積化、高性能化に伴って新たな微細加工技術
が開発されている。化学機械研磨（以下ＣＭＰと記す）
法もその一つであり、ＬＳＩ製造工程、特に多層配線形
成工程における層間絶縁膜の平坦化、金属プラグ形成、
埋め込み配線形成において頻繁に利用される技術であ
る。この技術は、例えば米国特許第４９４４８３６号明
細書に開示されている。2. Description of the Related Art In recent years, a new fine processing technology has been developed in accordance with high integration and high performance of a semiconductor integrated circuit (hereinafter, referred to as LSI). Chemical mechanical polishing (hereinafter referred to as CMP)
The method is one of them. For example, in an LSI manufacturing process, particularly, in a multilayer wiring forming process, an interlayer insulating film is flattened, a metal plug is formed,
This is a technique frequently used in the formation of embedded wiring. This technique is disclosed, for example, in US Pat. No. 4,944,836.
【０００３】また、最近はＬＳＩを高性能化するため
に、配線材料として銅及び銅合金の利用が試みられてい
る。しかし、銅及び銅合金は従来のアルミニウム合金配
線の形成で頻繁に用いられたドライエッチング法による
微細加工が困難である。そこで、あらかじめ溝を形成し
てある絶縁膜上に銅又は銅合金薄膜を堆積して埋め込
み、溝部以外の銅又は銅合金薄膜をＣＭＰにより除去し
て埋め込み配線を形成する、いわゆるダマシン法が主に
採用されている。この技術は、例えば特開平２−２７８
８２２号公報に開示されている。In recent years, in order to improve the performance of LSIs, attempts have been made to use copper and copper alloys as wiring materials. However, it is difficult to finely process copper and copper alloy by a dry etching method frequently used for forming a conventional aluminum alloy wiring. Therefore, a so-called damascene method is mainly used in which a copper or copper alloy thin film is deposited and buried on an insulating film in which a groove is formed in advance, and a copper or copper alloy thin film other than the groove is removed by CMP to form a buried wiring. Has been adopted. This technique is disclosed, for example, in Japanese Patent Laid-Open No. 2-278.
No. 822.
【０００４】銅及び銅合金等の金属ＣＭＰの一般的な方
法は、円形の研磨定盤（プラテン）上に研磨パッドを貼
り付け、研磨パッド表面を金属用研磨液で浸し、基板の
金属膜を形成した面を押し付けて、その裏面から所定の
圧力（以下研磨圧力と記す）を加えた状態で研磨定盤を
回し、研磨液と金属膜の凸部との機械的摩擦によって凸
部の金属膜を除去するものである。ＣＭＰに用いられる
金属用研磨液は、一般には酸化剤及び砥粒からなってお
り必要に応じてさらに酸化金属溶解剤、保護膜形成剤が
添加される。まず酸化剤によって金属膜表面を酸化し、
その酸化層を砥粒によって削り取るのが基本的なメカニ
ズムと考えられている。凹部の金属表面の酸化層は研磨
パッドにあまり触れず、砥粒による削り取りの効果が及
ばないので、ＣＭＰの進行とともに凸部の金属層が除去
されて基板表面は平坦化される。この詳細についてはジ
ャーナル・オブ・エレクトロケミカルソサエティ誌の第
１３８巻１１号（１９９１年発行）の３４６０〜３４６
４頁に開示されている。[0004] A general method of metal CMP such as copper and copper alloy is to attach a polishing pad on a circular polishing platen (platen), immerse the polishing pad surface with a metal polishing solution, and remove the metal film on the substrate. The formed surface is pressed, and the polishing platen is rotated while applying a predetermined pressure (hereinafter, referred to as polishing pressure) from the back surface, and the metal film of the convex portion is formed by mechanical friction between the polishing liquid and the convex portion of the metal film. Is to be removed. The metal polishing liquid used for CMP generally comprises an oxidizing agent and abrasive grains, and a metal oxide dissolving agent and a protective film forming agent are further added as necessary. First, oxidize the metal film surface with an oxidizing agent,
It is considered that a basic mechanism is to remove the oxide layer with abrasive grains. Since the oxide layer on the metal surface of the concave portion does not much contact the polishing pad and does not have the effect of shaving by the abrasive grains, the metal layer of the convex portion is removed with the progress of CMP, and the substrate surface is flattened. For details, refer to Journal of Electrochemical Society, Vol. 138, No. 11 (issued in 1991), 3460-346.
It is disclosed on page 4.
【０００５】ＣＭＰによる研磨速度を高める方法として
酸化金属溶解剤を添加することが有効とされている。砥
粒によって削り取られた金属酸化物の粒を研磨液に溶解
（以下エッチングと記す）させてしまうと砥粒による削
り取りの効果が増すためであるためと解釈できる。酸化
金属溶解剤の添加によりＣＭＰによる研磨速度は向上す
るが、一方、凹部の金属膜表面の酸化層もエッチング
（溶解）されて金属膜表面が露出すると、酸化剤によっ
て金属膜表面がさらに酸化され、これが繰り返されると
凹部の金属膜のエッチングが進行してしまう。このため
研磨後に埋め込まれた金属配線の表面中央部分が皿のよ
うに窪む現象（以下、ディッシングと記す。）が発生
し、平坦化効果が損なわれる。As a method of increasing the polishing rate by CMP, it is effective to add a metal oxide dissolving agent. It can be interpreted that dissolving the metal oxide particles removed by the abrasive grains in the polishing liquid (hereinafter referred to as etching) increases the effect of the abrasive grains to remove the metal oxide particles. The polishing rate by CMP is improved by the addition of the metal oxide dissolving agent. On the other hand, when the oxide layer on the surface of the metal film in the recess is also etched (dissolved) and the metal film surface is exposed, the metal film surface is further oxidized by the oxidizing agent. If this is repeated, the etching of the metal film in the concave portion proceeds. For this reason, a phenomenon in which the central portion of the surface of the metal wiring buried after polishing is depressed like a dish (hereinafter referred to as dishing) occurs, and the flattening effect is impaired.
【０００６】これを防ぐためにさらに保護膜形成剤が添
加される。保護膜形成剤は金属膜表面の酸化層上に保護
膜を形成し、酸化層の研磨液中への溶解を防止するもの
である。この保護膜は砥粒により容易に削り取ることが
可能で、ＣＭＰによる研磨速度を低下させないことが望
まれる。銅及び銅合金のディッシングや研磨中の腐食を
抑制し、信頼性の高いＬＳＩ配線を形成するために、グ
リシン等のアミノ酢酸又はアミド硫酸からなる酸化金属
溶解剤及び保護膜形成剤としてベンゾトリアゾール（Ｂ
ＴＡ）を含有する金属用研磨液を用いる方法が提唱され
ている。この技術は、例えば特開平８−８３７８０号公
報に記載されている。To prevent this, a protective film forming agent is further added. The protective film forming agent forms a protective film on the oxide layer on the surface of the metal film and prevents the oxide layer from dissolving in the polishing liquid. This protective film can be easily removed by abrasive grains, and it is desired that the polishing rate by CMP is not reduced. In order to suppress corrosion during dishing and polishing of copper and copper alloys and to form a highly reliable LSI wiring, a metal oxide dissolving agent composed of aminoacetic acid or amidosulfuric acid such as glycine and benzotriazole ( B
A method using a polishing slurry for metal containing TA) has been proposed. This technique is described, for example, in Japanese Patent Application Laid-Open No. 8-83780.
【０００７】銅及び銅合金のダマシン配線形成やタング
ステン等のプラグ配線形成等の金属埋め込み形成におい
ては、埋め込み部分以外に形成される層間絶縁膜である
二酸化シリコン膜の研磨速度も大きい場合には、層間絶
縁膜ごと配線の厚みが薄くなるシニングが発生する。そ
の結果、配線抵抗の増加やパターン密度等により抵抗の
ばらつきが生じるために、研磨される金属膜に対して二
酸化シリコン膜の研磨速度が十分小さい特性が要求され
る。そこで、酸の解離により生ずる陰イオンにより二酸
化シリコンの研磨速度を抑制することにより、研磨液の
ｐＨをｐＫａ−０．５よりも大きくする方法が提唱され
ている。この技術は、例えば特許第２８１９１９６号公
報に記載されている。In the formation of a metal buried layer such as the formation of a damascene wiring of copper or a copper alloy or the formation of a plug wiring of tungsten or the like, if the polishing rate of a silicon dioxide film which is an interlayer insulating film formed other than in the buried portion is high, Thinning occurs in which the thickness of the wiring is thinned together with the interlayer insulating film. As a result, variations in resistance occur due to an increase in wiring resistance, pattern density, and the like, so that the polishing rate of the silicon dioxide film is required to be sufficiently low with respect to the metal film to be polished. Therefore, a method has been proposed in which the polishing rate of the polishing liquid is made higher than pKa-0.5 by suppressing the polishing rate of silicon dioxide by anions generated by dissociation of the acid. This technique is described in, for example, Japanese Patent No. 2819196.
【０００８】一方、配線の銅又は銅合金等の下層には、
層間絶縁膜中への銅拡散防止のためにバリア層として、
タンタルやタンタル合金及び窒化タンタルやその他のタ
ンタル化合物等が形成される。したがって、銅又は銅合
金を埋め込む配線部分以外では、露出したバリア層をＣ
ＭＰにより取り除く必要がある。しかし、これらのバリ
ア層は、銅又は銅合金に比べ硬度が高いために、銅又は
銅合金用の研磨材料の組み合わせでは十分な研磨速度が
得られない場合が多い。そこで、銅又は銅合金を研磨す
る第１工程と、バリア層となる導体を研磨する第２工程
からなる２段研磨方法が検討されている。On the other hand, in the lower layer of the wiring such as copper or copper alloy,
As a barrier layer to prevent copper diffusion into the interlayer insulating film,
Tantalum, a tantalum alloy, tantalum nitride, other tantalum compounds, and the like are formed. Therefore, except for the wiring portion where copper or copper alloy is embedded, the exposed barrier layer is
Must be removed by MP. However, since these barrier layers have higher hardness than copper or copper alloy, a combination of polishing materials for copper or copper alloy often cannot provide a sufficient polishing rate. Therefore, a two-step polishing method including a first step of polishing copper or a copper alloy and a second step of polishing a conductor to be a barrier layer has been studied.
【０００９】第２工程であるバリア層となる導体のＣＭ
Ｐでは、銅及び銅合金埋め込み配線部のディッシングを
防止する必要があり、銅又は銅合金の研磨速度及びエッ
チング速度を抑制するために、研磨液のｐＨを小さくす
ることはマイナス効果であると考えられていた。バリア
層として用いられるタンタルやタンタル合金及び窒化タ
ンタルやその他のタンタル化合物は、化学的に安定でエ
ッチングが難しく、硬度が高いために機械的な研磨も銅
及び銅合金ほど容易ではない。そこで、砥粒の硬度を上
げた場合には、銅又は銅合金に研磨キズが発生して電気
特性不良の原因になったり、砥粒の粒子濃度を高くした
場合には、二酸化シリコン膜の研磨速度が大きくなって
しまいシニングが発生するという問題があった。In the second step, the CM of the conductor serving as the barrier layer is used.
In P, it is necessary to prevent dishing of the copper and copper alloy embedded wiring portion, and it is considered that lowering the pH of the polishing liquid has a negative effect in order to suppress the polishing rate and etching rate of copper or copper alloy. Had been. Tantalum, tantalum alloys, tantalum nitride, and other tantalum compounds used as barrier layers are chemically stable and difficult to etch, and have high hardness so that mechanical polishing is not as easy as copper and copper alloys. Therefore, when the hardness of the abrasive grains is increased, polishing scratches occur on copper or a copper alloy, causing electrical characteristics to be defective. When the particle concentration of the abrasive grains is increased, polishing of the silicon dioxide film is performed. There is a problem that the speed is increased and thinning occurs.
【００１０】[0010]
【発明が解決しようとする課題】本発明は、バリア層と
なる導体として用いられるタンタルやタンタル合金及び
窒化タンタルやその他のタンタル化合物等を低砥粒濃度
において高い研磨速度で研磨でき、かつ銅又は銅合金配
線のディッシングとシニング及び研磨キズ発生を抑制で
き、信頼性の高い金属膜の埋め込みパターン形成するこ
とができる導体用研磨液及びこれを用いた研磨方法を提
供するものである。SUMMARY OF THE INVENTION The present invention is capable of polishing a tantalum, a tantalum alloy, a tantalum nitride or other tantalum compounds used as a conductor to be a barrier layer at a high polishing rate at a low abrasive concentration, and is capable of polishing copper or copper. An object of the present invention is to provide a polishing slurry for a conductor and a polishing method using the same, which can suppress dishing and thinning of copper alloy wiring and generation of polishing scratches and can form a highly reliable embedded pattern of a metal film.
【００１１】[0011]
【課題を解決するための手段】本発明者らは、バリア層
となる導体として用いられるタンタルやタンタル合金及
び窒化タンタルやその他のタンタル化合物の研磨におい
て、砥粒粒径が大きすぎると、バリア層の研磨速度が低
下してしまい、二酸化シリコンの研磨速度が増加してし
まうことを見出した。更に、砥粒の平均粒径が小さくて
も、凝集していない一次粒子からなる砥粒であると二酸
化シリコンの研磨速度が増加してしまうことを見出し
た。この現象は、低ｐＨ領域かつ低酸化剤濃度領域でタ
ンタルやタンタル合金及び窒化タンタルやその他のタン
タル化合物を研磨する際に顕著である。本発明はこれら
の知見に基づいてなされたものである。Means for Solving the Problems In the polishing of tantalum, a tantalum alloy, tantalum nitride and other tantalum compounds used as a conductor serving as a barrier layer, the present inventors have found that if the grain size of the abrasive is too large, the barrier layer may be damaged. It has been found that the polishing rate of silicon dioxide decreases and the polishing rate of silicon dioxide increases. Furthermore, it has been found that, even if the average particle size of the abrasive grains is small, the polishing rate of silicon dioxide increases when the abrasive grains are composed of non-aggregated primary particles. This phenomenon is remarkable when polishing tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds in a low pH region and a low oxidant concentration region. The present invention has been made based on these findings.
【００１２】本発明は、砥粒、導体の酸化剤、金属表面
に対する保護膜形成剤、酸及び水を含有する研磨液であ
り、砥粒が一次粒子が平均２〜１０粒子凝集した平均粒
径が７０ｎｍ以下の２次粒子からなる粒子であることを
特徴とする導体用研磨液に関する。The present invention is a polishing liquid containing abrasive grains, an oxidizing agent for a conductor, an agent for forming a protective film on a metal surface, an acid and water, wherein the abrasive grains have an average particle diameter of 2 to 10 primary particles aggregated on average. Is a particle composed of secondary particles having a diameter of 70 nm or less.
【００１３】砥粒の平均粒径は好ましくは５０ｎｍ以下
であり、より好ましくは３０〜２０ｎｍである。また、
一次粒子が平均２〜５粒子凝集した２次粒子からなる粒
子からなることが好ましい。砥粒は、シリカ、アルミ
ナ、セリア、チタニア、ジルコニア及びゲルマニアより
選ばれた少なくとも１種であることが好ましく、コロイ
ダルシリカ又はコロイダルアルミナであることがより好
ましい。コロイダルシリカは、シリコンアルコキシドの
加水分解により製造したものが好ましいが、珪酸ナトリ
ウムを原料として製造したものも使用できる。砥粒濃度
は、０．０５〜３重量％であることが好ましい。The average grain size of the abrasive grains is preferably 50 nm or less, more preferably 30 to 20 nm. Also,
It is preferable that the primary particles be composed of particles composed of secondary particles in which 2 to 5 particles have averaged. The abrasive grains are preferably at least one selected from silica, alumina, ceria, titania, zirconia and germania, and more preferably colloidal silica or colloidal alumina. The colloidal silica is preferably manufactured by hydrolysis of silicon alkoxide, but may be manufactured using sodium silicate as a raw material. The abrasive concentration is preferably 0.05 to 3% by weight.
【００１４】導体用研磨液のｐＨは３以下、かつ導体の
酸化剤濃度が０．０１〜３重量％であることが好まし
い。導体用研磨液にはさらに水溶性高分子を含むことが
でき、その場合の導体の酸化剤濃度は、０．０１〜１．
５重量％であることが好ましい。導体用研磨剤をバリア
層となる導体用に使用する場合は、導体の酸化剤の濃度
は、０．０１〜１．５重量％であることが好ましい。It is preferable that the pH of the polishing slurry for a conductor is 3 or less and the oxidizing agent concentration of the conductor is 0.01 to 3% by weight. The conductor polishing liquid may further contain a water-soluble polymer. In this case, the conductor has an oxidant concentration of 0.01 to 1.
Preferably it is 5% by weight. When the conductor polishing agent is used for a conductor serving as a barrier layer, the concentration of the conductor oxidizing agent is preferably 0.01 to 1.5% by weight.
【００１５】水溶性高分子は、ポリアクリル酸もしくは
その塩、ポリアクリルアミド、ポリメタクリル酸もしく
はその塩、ポリアミド酸もしくはその塩、ポリアクリル
アミド、ポリビニルアルコール及びポリビニルピロリド
ンからなる群から選ばれた少なくとも１種が好ましい。The water-soluble polymer is at least one selected from the group consisting of polyacrylic acid or a salt thereof, polyacrylamide, polymethacrylic acid or a salt thereof, polyamic acid or a salt thereof, polyacrylamide, polyvinyl alcohol and polyvinylpyrrolidone. Is preferred.
【００１６】酸は、有機酸であることが好ましく、マロ
ン酸、リンゴ酸、酒石酸、グリコール酸及びクエン酸か
ら選ばれた少なくとも１種であることがより好ましい。The acid is preferably an organic acid, more preferably at least one selected from malonic acid, malic acid, tartaric acid, glycolic acid and citric acid.
【００１７】導体の酸化剤は、過酸化水素、硝酸、過ヨ
ウ素酸カリウム、次亜塩素酸、オゾン水より選ばれた少
なくとも１種であることが好ましい。The oxidizing agent for the conductor is preferably at least one selected from hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid, and ozone water.
【００１８】導体は、銅又は銅合金のバリア層となる導
体であることが好ましく、銅又は銅合金のバリア層とな
る導体が、タンタル、窒化タンタル、タンタル合金、そ
の他のタンタル化合物であることが好ましい。Preferably, the conductor is a conductor serving as a copper or copper alloy barrier layer, and the conductor serving as a copper or copper alloy barrier layer is tantalum, tantalum nitride, a tantalum alloy, or another tantalum compound. preferable.
【００１９】金属表面に対する保護膜形成剤は、銅又は
銅合金等の金属導体の表面を腐食から保護するもので、
従来から広く用いられてきたベンゾトリアゾール（ＢＴ
Ａ）及びその誘導体から選ばれた少なくとも一種（ＢＴ
Ａ類）が好ましく用いられる。The protective film forming agent for the metal surface protects the surface of the metal conductor such as copper or copper alloy from corrosion.
Benzotriazole (BT) which has been widely used in the past
A) and at least one selected from the derivatives thereof (BT)
A) is preferably used.
【００２０】本発明は、また、上記の導体用研磨液を用
いて、タンタル、窒化タンタル、タンタル合金又はその
他のタンタル化合物からなるバリア層を研磨する研磨方
法に関する。The present invention also relates to a polishing method for polishing a barrier layer made of tantalum, tantalum nitride, a tantalum alloy or another tantalum compound using the above-mentioned polishing slurry for a conductor.
【００２１】本発明は、また、上記の導体用研磨液を用
いて、銅又は銅合金とそのバリア層を含む面を研磨する
研磨方法に関する。The present invention also relates to a polishing method for polishing a surface containing copper or a copper alloy and its barrier layer using the above-mentioned polishing liquid for a conductor.
【００２２】本発明では、平均粒径が７０ｎｍ以下、か
つ一次粒子が平均２〜１０粒子凝集した二次粒子からな
る砥粒を含有し、研磨液を好ましくは低ｐＨ領域かつ低
酸化剤濃度領域にすることにより、銅又は銅合金配線の
ディッシングとシニング及び研磨キズ発生を抑制し、低
砥粒濃度においてバリア層の高い研磨速度を実現するこ
とができる。バリア層を研磨する方法として、砥粒の硬
度を上げた場合には、銅合金に研磨キズが発生して電気
特性不良の原因になったり、砥粒の粒子濃度を高くした
場合には、二酸化シリコン膜の研磨速度が大きくなりシ
ニングが発生してしまうという問題があったが、本発明
の研磨液を用いると、バリア層として用いられるタンタ
ルやタンタル合金及び窒化タンタルやその他のタンタル
化合物の研磨が低ｐＨ領域かつ低酸化剤濃度領域で容易
に進行する。また、これらの研磨速度が最大になる砥粒
濃度が低濃度領域に存在し、酸化剤濃度が低い場合に、
一般に低ｐＨ領域で問題になる銅又は銅合金のエッチン
グ速度の増加による配線のディッシングも問題となら
ず、砥粒濃度が低いためにシニングも少ない。In the present invention, the polishing slurry preferably contains abrasive grains composed of secondary particles having an average particle diameter of 70 nm or less and primary particles having an average of 2 to 10 particles, and the polishing liquid is preferably in a low pH region and a low oxidizing agent concentration region. By doing so, dishing and thinning of copper or copper alloy wiring and occurrence of polishing scratches can be suppressed, and a high polishing rate of the barrier layer can be realized at a low abrasive concentration. As a method of polishing the barrier layer, when the hardness of the abrasive grains is increased, polishing flaws are generated in the copper alloy to cause poor electrical characteristics, and when the particle concentration of the abrasive grains is increased, the carbon dioxide is removed. There was a problem that the polishing rate of the silicon film was increased and thinning occurred.However, when the polishing liquid of the present invention was used, polishing of tantalum, a tantalum alloy, a tantalum nitride, and other tantalum compounds used as a barrier layer was performed. It proceeds easily in the low pH region and low oxidant concentration region. Also, when the abrasive concentration at which these polishing rates are maximized exists in the low concentration region and the oxidant concentration is low,
In general, dishing of wiring due to an increase in the etching rate of copper or copper alloy, which is a problem in a low pH region, does not cause a problem, and thinning is less due to a low abrasive concentration.
【００２３】[0023]
【発明の実施の形態】例えば、表面に二酸化シリコンの
凹部を有する基板上にバリア層及び銅又は銅合金を含む
導体膜を形成・充填したものを、まず、銅又は銅合金／
バリア層の研磨速度比が十分大きい銅又は銅合金用の研
磨液を用いてＣＭＰすると、基板の凸部のバリア層が表
面に露出し、凹部に銅又は銅合金膜が残された所望の導
体パターンが得られる。本発明の導体用研磨液は、砥
粒、導体の酸化剤、金属表面に対する保護膜形成剤、酸
及び水を含有する研磨液であり、砥粒は平均粒径が７０
ｎｍ以下かつ一次粒子が平均２〜１０粒子凝集した二次
粒子からなるものである。平均粒径が７０ｎｍより大き
いとバリア層の研磨速度が小さく、二酸化シリコン膜の
研磨速度が大きい。また、平均粒径が７０ｎｍ以下であ
っても、一次粒子が平均２粒子以上凝集していない粒子
であると二酸化シリコン膜の研磨速度が大きくなる。ま
た、一次粒子が平均１０粒子を超えて凝集して、平均粒
径が７０ｎｍ以下になる粒子は製造が困難である。DETAILED DESCRIPTION OF THE INVENTION For example, a substrate having a concave portion of silicon dioxide on its surface, on which a barrier layer and a conductor film containing copper or a copper alloy are formed and filled, is first formed of copper or copper alloy /
When the CMP is performed using a polishing liquid for copper or copper alloy having a sufficiently large polishing rate ratio of the barrier layer, a desired conductor in which the barrier layer of the convex portion of the substrate is exposed on the surface and the copper or copper alloy film remains in the concave portion A pattern is obtained. The polishing slurry for a conductor of the present invention is a polishing slurry containing abrasive grains, an oxidizing agent for a conductor, a protective film forming agent for a metal surface, an acid and water, and the abrasive grains have an average particle diameter of 70.
It is composed of secondary particles of not more than nm and primary particles having an average of 2 to 10 particles aggregated. When the average particle size is larger than 70 nm, the polishing rate of the barrier layer is low, and the polishing rate of the silicon dioxide film is high. Further, even if the average particle diameter is 70 nm or less, the polishing rate of the silicon dioxide film increases if the primary particles are not aggregated by two or more particles on average. Further, it is difficult to produce particles in which the primary particles aggregate more than 10 particles on average and the average particle diameter is 70 nm or less.
【００２４】本発明の砥粒の平均粒径は、光回折散乱式
粒度分布計（例えば、COULTER Electronics社製の COUL
TER N４SD）を用いて、測定温度２０℃でｉｎｔｅｎｓ
ｉｔｙ（散乱強度、濁度に相当）が５Ｅ＋０４〜４Ｅ＋
０５の範囲になるように調整して（強度が強すぎる場合
には純水で希釈して）５回測定し、Ｕｎｉｍｏｄａｌ値
の平均値を求めた。なお、溶媒屈折率：１．３３３
（水）、粒子屈折率：ｕｎｋｎｏｗｎ（という設定）、
溶媒粘度：１．００５ｃｐ（水）、Ｒｕｎ Ｔｉｍｅ：
２００ｓｅｃ、レーザー入射角：９０°で行った。ま
た、粒子の凝集度は、透過型電子顕微鏡（例えば（株）
日立製作所製のH-７１００FA）を用いて、研磨液をミク
ロメッシュ上で凝集が発生しないように乾燥させて１０
〜５０万倍で測定した。凝集度は２次粒子の２００個の
凝集粒子数を観察して平均値を求めた。The average particle size of the abrasive grains of the present invention can be measured using a light diffraction scattering type particle size distribution meter (for example, COULTER Electronics Co., Ltd.).
TER N4SD) and intense at a measurement temperature of 20 ° C.
ity (corresponding to scattering intensity and turbidity) is 5E + 04 to 4E +
The measurement was performed five times while adjusting to be in the range of 05 (diluted with pure water when the strength was too strong), and the average value of Unimodal values was obtained. The solvent refractive index was 1.333.
(Water), particle refractive index: unknown (setting),
Solvent viscosity: 1.005 cp (water), Run Time:
The measurement was performed for 200 sec at a laser incident angle of 90 °. The degree of aggregation of the particles can be measured by a transmission electron microscope (for example,
The polishing liquid was dried using H-7100FA manufactured by Hitachi, Ltd. to prevent agglomeration from occurring on the micromesh.
It was measured at ~ 500,000 times. The average degree of aggregation was determined by observing the number of aggregated particles of 200 secondary particles.
【００２５】導体用研磨液のｐＨは、３より大きいとタ
ンタルやタンタル合金及び窒化タンタルやその他のタン
タル化合物の研磨速度が小さくなる傾向がある。ｐＨは
酸の添加量により調整することができる。またアンモニ
ア、水酸化ナトリウム、テトラメチルアンモニウムハイ
ドライド等のアルカリ成分の添加によっても調整可能で
ある。When the pH of the polishing slurry for a conductor is more than 3, the polishing rate of tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds tends to decrease. The pH can be adjusted by the amount of acid added. It can also be adjusted by adding an alkali component such as ammonia, sodium hydroxide, or tetramethylammonium hydride.
【００２６】一方、本発明における導体用研磨液は、導
体の酸化剤の濃度が０．１５重量％付近でタンタルやタ
ンタル合金及び窒化タンタルやその他のタンタル化合物
の研磨速度が極大になる。導体の酸化剤によりタンタル
やタンタル合金及び窒化タンタルやその他のタンタル化
合物等の導体膜表面に、機械的に研磨されやすい一次酸
化層が形成され、高い研磨速度が得られる。一般にｐＨ
が３以下の場合には、銅又は銅合金膜のエッチング速度
が大きく、金属表面に対する保護膜形成剤でのエッチン
グ抑制は困難である。しかし、本発明では、導体の酸化
剤の濃度を十分低くすると、金属表面に対する保護膜形
成剤によるエッチング抑制が可能である。導体の酸化剤
の濃度が３重量％より大きいと、銅又は銅合金のエッチ
ング速度が大きくなりディッシング等が発生し易くなる
だけでなく、タンタルやタンタル合金及び窒化タンタル
やその他のタンタル化合物等の導体膜表面に、一次酸化
層よりも研磨されにくい二次酸化層が形成されるために
研磨速度が低下する傾向がある。酸化剤の濃度が０．０
１重量％よりも小さいと、酸化層が充分形成されないた
めに研磨速度が小さくなり、タンタル膜等の剥離等が発
生することもある。On the other hand, in the polishing slurry for conductor in the present invention, the polishing rate of tantalum, tantalum alloy, tantalum nitride and other tantalum compounds is maximized when the concentration of the oxidizing agent of the conductor is around 0.15% by weight. A primary oxide layer that is easily mechanically polished is formed on the surface of a conductive film such as tantalum, a tantalum alloy, tantalum nitride, or another tantalum compound by the oxidizing agent of the conductor, and a high polishing rate can be obtained. Generally pH
Is 3 or less, the etching rate of the copper or copper alloy film is high, and it is difficult to suppress the etching of the metal surface with the protective film forming agent. However, in the present invention, if the concentration of the oxidizing agent in the conductor is sufficiently reduced, the etching of the metal surface by the protective film forming agent can be suppressed. When the concentration of the oxidizing agent in the conductor is more than 3% by weight, not only the etching rate of copper or copper alloy is increased and dishing easily occurs, but also the conductor such as tantalum, tantalum alloy, tantalum nitride, and other tantalum compounds is used. Since a secondary oxide layer that is less polished than the primary oxide layer is formed on the film surface, the polishing rate tends to decrease. Oxidant concentration of 0.0
If the amount is less than 1% by weight, the oxide layer is not sufficiently formed, so that the polishing rate becomes low, and peeling of the tantalum film or the like may occur.
【００２７】本発明における導体用研磨液の導体の酸化
剤は、水溶性高分子を含有する場合には、濃度が０．０
１〜１．５重量％であることが好ましい。水溶性高分子
は、タンタルやタンタル合金及び窒化タンタルやその他
のタンタル化合物、又はその酸化膜表面に吸着するため
に、高い研磨速度が得られる酸化剤濃度範囲が小さくな
る。また、水溶性高分子は、特に窒化タンタル膜や窒化
チタン等の窒化化合物膜の表面に吸着し易いために、窒
化タンタル膜や窒化チタン等の窒化化合物膜の研磨速度
が小さくなる。一方、水溶性高分子は、金属の表面保護
膜形成効果を持ち、ディッシングやシニング等の平坦化
特性を向上させる。The oxidizing agent for the conductor of the polishing slurry for a conductor according to the present invention, when containing a water-soluble polymer, has a concentration of 0.0
It is preferably from 1 to 1.5% by weight. Since the water-soluble polymer is adsorbed on tantalum, a tantalum alloy, tantalum nitride, other tantalum compounds, or the surface of an oxide film thereof, the oxidizing agent concentration range in which a high polishing rate can be obtained is small. Further, since the water-soluble polymer is easily adsorbed on the surface of a nitride compound film such as a tantalum nitride film or titanium nitride, the polishing rate of the nitride compound film such as a tantalum nitride film or titanium nitride decreases. On the other hand, the water-soluble polymer has a metal surface protective film forming effect and improves flattening characteristics such as dishing and thinning.
【００２８】本発明における導体の酸化剤としては、過
酸化水素（Ｈ2Ｏ2）、硝酸、過ヨウ素酸カリウム、次亜
塩素酸、オゾン水等が挙げられ、その中でも過酸化水素
が特に好ましい。基板が集積回路用素子を含むシリコン
基板である場合、アルカリ金属、アルカリ土類金属、ハ
ロゲン化物などによる汚染は望ましくないので、不揮発
成分を含まない酸化剤が望ましい。但し、オゾン水は組
成の時間変化が激しいので過酸化水素が最も適してい
る。但し、適用対象の基板が半導体素子を含まないガラ
ス基板などである場合は不揮発成分を含む酸化剤であっ
ても差し支えない。Examples of the oxidizing agent for the conductor in the present invention include hydrogen peroxide (H 2 O 2 ), nitric acid, potassium periodate, hypochlorous acid, ozone water and the like. Of these, hydrogen peroxide is particularly preferred. . When the substrate is a silicon substrate including an element for an integrated circuit, contamination by an alkali metal, an alkaline earth metal, a halide, or the like is not desirable, and an oxidizing agent containing no nonvolatile component is desirable. However, hydrogen peroxide is most suitable because the composition of ozone water changes drastically with time. However, when the substrate to be applied is a glass substrate or the like containing no semiconductor element, an oxidizing agent containing a nonvolatile component may be used.
【００２９】本発明における酸としては、ギ酸、酢酸、
プロピオン酸、吉草酸、２−メチル酪酸、ｎ−ヘキサン
酸、３，３−ジメチル酪酸、２−エチル酪酸、４−メチ
ルペンタン酸、ｎ−ヘプタン酸、２−メチルヘキサン
酸、ｎ−オクタン酸、２−エチルヘキサン酸、安息香
酸、グリコール酸、サリチル酸、グリセリン酸、シュウ
酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピ
メリン酸、マレイン酸、フタル酸、リンゴ酸、酒石酸、
クエン酸等、及びこれらの有機酸のアンモニウム塩等の
塩、硫酸、硝酸、アンモニア、アンモニウム塩類、例え
ば過硫酸アンモニウム、硝酸アンモニウム、塩化アンモ
ニウム、クロム酸等又はそれらの混合物等が挙げられ
る。これらの中では、実用的なＣＭＰ研磨速度が得られ
るという点で有機酸、特に、マロン酸、リンゴ酸、酒石
酸、グリコール酸及びクエン酸が好ましい。As the acid in the present invention, formic acid, acetic acid,
Propionic acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid,
Examples thereof include citric acid and the like, and salts of these organic acids such as ammonium salt, sulfuric acid, nitric acid, ammonia, ammonium salts such as ammonium persulfate, ammonium nitrate, ammonium chloride, chromic acid and the like, and mixtures thereof. Among these, organic acids, particularly malonic acid, malic acid, tartaric acid, glycolic acid and citric acid are preferable in that a practical CMP polishing rate can be obtained.
【００３０】本発明における金属表面に対する保護膜形
成剤は、ＢＴＡ（ベンゾトリアゾール）及びその誘導
体、例えばＢＴＡのベンゼン環の一つの水素原子をメチ
ル基で置換したもの（トリルトリアゾール）もしくはカ
ルボキシル基等で置換したもの（ベンゾトリアゾール−
４−カルボン酸のメチル、エチル、プロピル、ブチル及
びオクチルエステル）、又はナフトトリアゾール、ナフ
トトリアゾール誘導体及びこれらを含む混合物の中から
選ばれた少なくとも１種が好ましく用いられる。The protective film forming agent for the metal surface in the present invention is BTA (benzotriazole) or a derivative thereof, for example, one obtained by substituting one hydrogen atom of the benzene ring of BTA with a methyl group (tolyltriazole) or a carboxyl group. Substituted (benzotriazole-
Methyl, ethyl, propyl, butyl and octyl esters of 4-carboxylic acid), or at least one selected from naphthotriazole, naphthotriazole derivatives and mixtures containing these are preferably used.
【００３１】本発明における水溶性高分子としては、以
下の群から選ばれた少なくとも１種が好適に用いられ
る。すなわち、ポリアクリル酸、ポリアクリル酸アンモ
ニウム塩、ポリアクリル酸ナトリウム塩、ポリメタクリ
ル酸、ポリメタクリル酸アンモニウム塩、ポリメタクリ
ル酸ナトリウム塩、ポリアクリルアミド等のカルボキシ
ル基を持つモノマーを基本構成単位とするポリマー及び
その塩、ポリビニルアルコール及びポリビニルピロリド
ン等のビニル基を持つモノマーを基本構成単位とするポ
リマーからなる群が挙げられる。但し、適用する基板が
半導体集積回路用シリコン基板などの場合はアルカリ金
属、アルカリ土類金属、ハロゲン化物等による汚染は望
ましくないため、酸もしくはそのアンモニウム塩が望ま
しい。基板がガラス基板等である場合はその限りではな
い。これらの水溶性高分子を添加することにより、前記
保護膜形成剤によるエッチング抑止効果によりディッシ
ング特性を向上させることができる。As the water-soluble polymer in the present invention, at least one selected from the following group is preferably used. That is, a polymer having a monomer having a carboxyl group such as polyacrylic acid, ammonium polyacrylate, sodium polyacrylate, polymethacrylic acid, ammonium polymethacrylate, sodium polymethacrylate, or polyacrylamide as a basic structural unit. And a salt thereof, and a polymer including a monomer having a vinyl group such as polyvinyl alcohol and polyvinyl pyrrolidone as a basic structural unit. However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, an acid or an ammonium salt thereof is preferable because contamination with an alkali metal, an alkaline earth metal, a halide or the like is not desirable. This is not the case when the substrate is a glass substrate or the like. By adding these water-soluble polymers, dishing characteristics can be improved due to the etching inhibiting effect of the protective film forming agent.
【００３２】本発明の導体用研磨液の砥粒としては、シ
リカ、アルミナ、ジルコニア、セリア、チタニア、ゲル
マニア、炭化珪素等の無機物砥粒、ポリスチレン、ポリ
アクリル酸、ポリ塩化ビニル等の有機物砥粒のいずれで
もよいが、研磨液中での分散安定性が良く、ＣＭＰによ
り発生する研磨傷（スクラッチ）の発生数の少ない、平
均粒径が７０ｎｍ以下のコロイダルシリカ、コロイダル
アルミナが好ましく、平均粒径が５０ｎｍ以下のコロイ
ダルシリカ、コロイダルアルミナがより好ましい。平均
粒径は、バリア層の研磨速度がより大きくなり、二酸化
シリコンの研磨速度がより小さくなる３０ｎｍ以下が更
に好ましい。コロイダルシリカはシリコンアルコキシド
の加水分解又は珪酸ナトリウムのイオン交換による製造
方法が知られており、コロイダルアルミナは硝酸アルミ
ニウムの加水分解による製造方法が知られている。The abrasive grains of the polishing slurry for conductors of the present invention include inorganic abrasive grains such as silica, alumina, zirconia, ceria, titania, germania, and silicon carbide; and organic abrasive grains such as polystyrene, polyacrylic acid, and polyvinyl chloride. However, colloidal silica or colloidal alumina having a good dispersion stability in a polishing liquid, a small number of polishing scratches (scratch) generated by CMP, and an average particle size of 70 nm or less is preferable. Is more preferably 50 nm or less, colloidal silica or colloidal alumina. The average particle size is more preferably 30 nm or less at which the polishing rate of the barrier layer becomes higher and the polishing rate of silicon dioxide becomes lower. A method of producing colloidal silica by hydrolysis of silicon alkoxide or ion exchange of sodium silicate is known, and a method of producing colloidal alumina by hydrolysis of aluminum nitrate is known.
【００３３】本発明を適用する導体としては、基板に導
体として埋め込まれ、研磨されて平坦化されて電導性を
有する配線材料となるものであれば、特に限定されない
が、銅又は銅合金のバリア層となる導体であることが好
ましく、タンタルやタンタル合金及び窒化タンタルやそ
の他のタンタル化合物が好ましい。The conductor to which the present invention is applied is not particularly limited as long as the conductor is embedded in the substrate as a conductor, polished and flattened to become a conductive wiring material. The conductor to be a layer is preferably used, and tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds are preferable.
【００３４】本発明における酸の配合量は、導体の酸化
剤、酸、金属表面に対する保護膜形成剤、必要により配
合される水溶性高分子及び水の総量１００ｇに対して、
０．０００１〜０．０５molとすることが好ましく、
０．００１mol〜０．０１molとすることがより好まし
い。この配合量が０．０５molを超えると、銅合金のエ
ッチングが増加する傾向がある。In the present invention, the compounding amount of the acid is based on the total amount of 100 g of the oxidizing agent of the conductor, the acid, the protective film forming agent for the metal surface, the water-soluble polymer and the water compounded as necessary.
It is preferably 0.0001 to 0.05 mol,
More preferably, it is 0.001 mol to 0.01 mol. If the amount exceeds 0.05 mol, the etching of the copper alloy tends to increase.
【００３５】本発明における金属表面に対する保護膜形
成剤の配合量は、導体の酸化剤、酸、金属表面に対する
保護膜形成剤、必要により配合される水溶性高分子及び
水の総量１００ｇに対して、０．０００１mol〜０．０
１molとすることが好ましく、０．０００５mol〜０．０
０５molとすることがより好ましい。この配合量が０．
０００１mol未満では、銅合金のエッチングが増加する
傾向があり、０．０１molを超えても効果に変わりがな
い。In the present invention, the compounding amount of the protective film forming agent for the metal surface is based on the total amount of 100 g of the oxidizing agent of the conductor, the acid, the protective film forming agent for the metal surface, the water-soluble polymer and the water compounded if necessary. , 0.0001 mol-0.0
1 mol, preferably 0.0005 mol to 0.0 mol
More preferably, it is 05 mol. When the blending amount is 0.
If it is less than 0001 mol, the etching of the copper alloy tends to increase, and if it exceeds 0.01 mol, the effect remains unchanged.
【００３６】本発明における水溶性高分子の配合量は、
導体の酸化剤、酸、金属表面に対する保護膜形成剤、水
溶性高分子及び水の総量１００ｇに対して、０．００１
〜０．５重量％とすることが好ましく、０．０１重量％
〜０．２重量％とすることがより好ましい。この配合量
が０．００１重量％未満では、エッチング抑制において
保護膜形成剤との併用効果が現れない傾向があり、０．
５重量％を超えると、ＣＭＰによる研磨速度が低下する
傾向がある。The amount of the water-soluble polymer in the present invention is as follows:
0.001 to the total amount of 100 g of the oxidizing agent of the conductor, the acid, the protective film forming agent for the metal surface, the water-soluble polymer and water.
０．５0.5% by weight, preferably 0.01% by weight
More preferably, the content is set to 0.2% by weight. If the amount is less than 0.001% by weight, the effect of using the protective film forming agent in combination with the protective film tends not to be exhibited in suppressing etching.
If it exceeds 5% by weight, the polishing rate by CMP tends to decrease.
【００３７】[0037]
【実施例】以下、実施例により本発明を説明する。本発
明はこれらの実施例により制限されるものではない。The present invention will be described below with reference to examples. The present invention is not limited by these examples.
【００３８】実施例１〜３、比較例１〜３ 《研磨液の作製方法》リンゴ酸０．４重量％、砥粒１．
０重量％及び保護膜形成剤としてのＢＴＡ０．２重量％
に水９７．９重量％を加えて溶解し、過酸化水素水（試
薬特級、３０％水溶液）を０．５重量％加えて得られた
ものを導体用研磨液とした。砥粒としては、テトラエト
キシシランのアンモニア溶液中での加水分解により作製
し、テトラエトキシシラン濃度、アンモニア濃度、反応
温度を調整することにより砥粒粒径、凝集数を調整して
得られた表１に示す砥粒粒径２５〜１００ｎｍの範囲の
コロイダルシリカを用いた。使用したリンゴ酸のｐＫａ
は、３．４である。実施例１〜３、比較例１〜３では表
１に示す砥粒を含む上記導体用研磨液を用いてＣＭＰし
た。Examples 1 to 3 and Comparative Examples 1 to 3 << Method of preparing polishing liquid >> Malic acid 0.4% by weight, abrasive grains 1.
0% by weight and 0.2% by weight of BTA as a protective film forming agent
Was added and mixed with 97.9% by weight of water, and 0.5% by weight of hydrogen peroxide solution (reagent grade, 30% aqueous solution) was added to obtain a polishing slurry for conductor. The abrasive grains were prepared by hydrolyzing tetraethoxysilane in an ammonia solution, and adjusting the tetraethoxysilane concentration, the ammonia concentration, and the reaction temperature to adjust the abrasive grain diameter and the number of agglomerations. Colloidal silica having an abrasive grain diameter of 25 to 100 nm shown in No. 1 was used. PKa of malic acid used
Is 3.4. In Examples 1 to 3 and Comparative Examples 1 to 3, CMP was performed using the above-mentioned polishing slurry for conductors containing the abrasive grains shown in Table 1.
【００３９】《研磨条件》 基板： 厚さ２００ｎｍのタンタル膜を形成した配線形成のない
二酸化シリコン膜層付きシリコン基板 厚さ１００ｎｍの窒化タンタル膜を形成した配線形成の
ない二酸化シリコン膜層付きシリコン基板 厚さ１μｍの二酸化シリコン膜を形成したシリコン基板 厚さ１μｍの銅膜を形成した配線形成のない二酸化シリ
コン膜層付きシリコン基板 銅配線パターン付きシリコン基板 研磨パッド：独立気泡を持つ発泡ポリウレタン樹脂 研磨圧力：２５ＫＰａ 基板と研磨定盤との相対速度：１８ｍ／ｍｉｎ<< Polishing Conditions >> Substrate: A silicon substrate with a silicon dioxide film layer without a wiring formed thereon having a 200 nm thick tantalum film formed thereon A silicon substrate with a silicon dioxide film layer without a wiring formed thereon having a 100 nm thick tantalum nitride film formed thereon Silicon substrate with a silicon dioxide film with a thickness of 1 μm Silicon substrate with a silicon dioxide film layer without a wiring with a copper film with a thickness of 1 μm Silicon substrate with a copper wiring pattern Polishing pad: foamed polyurethane resin with closed cells Polishing pressure : 25KPa Relative speed between substrate and polishing platen: 18m / min
【００４０】《研磨品評価項目》 ＣＭＰによる研磨速度：タンタル膜、窒化タンタル膜、
銅膜については、例えばナプソン（株）製Ｍｏｄｅｌ
ＲＴ−７を用いてシート抵抗値を測定し、抵抗率から膜
厚を計算し、ＣＭＰ前後での膜厚差を求めた。このと
き、銅膜の抵抗率は１．８３μΩｃｍ、タンタル膜の抵
抗率は１８４μΩｃｍ、窒化タンタル膜の抵抗率は２６
３μΩｃｍを用いた。二酸化シリコン膜の膜厚は光干渉
式膜厚計（例えばナノメトリクス（株）製、Nanospec
Model 5100）で測定し、ＣＭＰ前後の膜厚差を求め
た。このとき二酸化シリコン膜の屈折率は１．４５を用
いた。<< Evaluation Items of Polished Article >> Polishing rate by CMP: tantalum film, tantalum nitride film,
As for the copper film, for example, Model manufactured by Napson Corporation
The sheet resistance was measured using RT-7, the film thickness was calculated from the resistivity, and the difference in film thickness before and after CMP was determined. At this time, the resistivity of the copper film is 1.83 μΩcm, the resistivity of the tantalum film is 184 μΩcm, and the resistivity of the tantalum nitride film is 26.
3 μΩcm was used. The thickness of the silicon dioxide film is measured by an optical interference type thickness meter (for example, Nanospec Co., Ltd., Nanospec
(Model 5100), and the difference in film thickness before and after CMP was determined. At this time, the refractive index of the silicon dioxide film was 1.45.
【００４１】ディッシング量：二酸化シリコン中に深さ
０．５μｍの溝を形成して、公知のスパッタ法によって
バリア層として厚さ５０ｎｍの窒化タンタル膜を形成
し、同様にスパッタ法により銅膜を形成して公知の熱処
理によって埋め込んだシリコン基板を基板として用いて
銅膜の研磨とバリア層の研磨とからなる２段研磨を行
い、触針式段差計（例えば、Ｖｅｅｃｏ／Ｓｌｏａｎ社
製Ｄｅｋｔａｔ３０３０）で配線金属部（銅）幅１００
μｍ、絶縁膜（二酸化シリコン）部幅１００μｍが交互
に並んだストライプ状パターン部の表面形状から、絶縁
膜部に対する配線金属部の膜減り量を測定し、表２に示
した。銅膜用の１段目研磨液としては、窒化タンタルに
対する銅の研磨速度比が十分大きい銅及び銅合金用の研
磨液（日立砥粒フリーＣ４３０Ｋスラリー）を使用して
研磨した。１段研磨後に、絶縁膜部上にバリア層が露出
した状態で測定したディッシング量が、５０ｎｍになる
ように基板サンプルを作製しておき、次に、バリア層用
の２段目研磨液として、実施例及び比較例の研磨液を用
いて絶縁膜部でバリア層がなくなるまで２段研磨し、配
線金属部の膜減り量を測定した。Dishing amount: A groove having a depth of 0.5 μm is formed in silicon dioxide, a 50 nm-thick tantalum nitride film is formed as a barrier layer by a known sputtering method, and a copper film is similarly formed by a sputtering method. Using a silicon substrate embedded by a known heat treatment as a substrate, two-stage polishing including polishing of a copper film and polishing of a barrier layer is performed, and wiring is performed by a stylus type step meter (for example, Dektat 3030 manufactured by Veeco / Sloan). Metal part (copper) width 100
The amount of film reduction of the wiring metal part relative to the insulating film part was measured from the surface shape of the stripe pattern part in which the width of the insulating film (silicon dioxide) part was 100 μm. As the first-stage polishing liquid for the copper film, polishing was performed using a polishing liquid (Hitachi abrasive-free C430K slurry) for copper and copper alloy having a sufficiently high polishing rate ratio of copper to tantalum nitride. After the first-stage polishing, a substrate sample was prepared so that the dishing amount measured in a state where the barrier layer was exposed on the insulating film portion was 50 nm. Next, as a second-stage polishing liquid for the barrier layer, Using the polishing liquids of Examples and Comparative Examples, the insulating film portion was polished in two steps until the barrier layer disappeared, and the amount of film reduction of the wiring metal portion was measured.
【００４２】シニング量：上記ディッシング量評価用基
板に形成された配線金属部幅４．５μｍ、絶縁膜部幅
０．５μｍが交互に並んだ総幅２．５ｍｍのストライプ
状パターン部を上記と同じ研磨液を用いて、銅膜の研磨
とバリア層の研磨とからなる２段研磨を行い、表面形状
を触針式段差計により測定し、ストライプ状パターン周
辺の絶縁膜フィールド部に対するパターン中央付近の絶
縁膜部の膜減り量を測定し、表２に示した。１段研磨
は、１段研磨後に、絶縁膜部上にバリア層が露出した状
態で測定したシニング量が２０ｎｍになるように行って
基板サンプルを作製しておき、次に絶縁膜部でバリア層
がなくなるまで２段研磨を行い、このときの膜減り量を
測定した。Thinning amount: A 2.5-mm-wide stripe pattern portion in which the wiring metal portion width of 4.5 μm and the insulating film portion width of 0.5 μm formed on the dishing amount evaluation substrate are alternately arranged is the same as above. Using a polishing solution, two-step polishing consisting of polishing of a copper film and polishing of a barrier layer is performed, and the surface shape is measured with a stylus-type profilometer. The amount of film loss of the insulating film was measured and is shown in Table 2. The one-step polishing is performed so that a thinning amount measured in a state where the barrier layer is exposed on the insulating film part is 20 nm after the one-step polishing to prepare a substrate sample, and then the barrier layer is formed on the insulating film part. The two-stage polishing was carried out until there was no more, and the amount of film reduction at this time was measured.
【００４３】実施例１〜３、比較例１〜３における、Ｃ
ＭＰによる研磨速度は表１に示すようであり、ディッシ
ング量及びシニング量は表２に示すようであった。C in Examples 1 to 3 and Comparative Examples 1 to 3
The polishing rates by MP were as shown in Table 1, and the amounts of dishing and thinning were as shown in Table 2.
【００４４】[0044]
【表１】 [Table 1]
【００４５】[0045]
【表２】 [Table 2]
【００４６】実施例１〜３では、バリア層導体であるタ
ンタル及び窒化タンタル膜の研磨速度が大きく、二酸化
シリコン膜の研磨速度が比較的小さいので、良好なディ
ッシング及びシニング特性が得られる。それに対し、比
較例１及び３では、バリア層膜（タンタル膜）の研磨速
度が減少し、二酸化シリコン膜の研磨速度がかなり大き
くなるためにディッシング及びシニング特性が悪化し
た。比較例２では、バリア層膜（タンタル膜）の研磨速
度は大きいが、二酸化シリコン膜の研磨速度がかなり大
きくなるためにディッシング及びシニング特性が悪化し
た。In Examples 1 to 3, since the polishing rate of the tantalum and tantalum nitride films as the barrier layer conductors is high and the polishing rate of the silicon dioxide film is relatively low, good dishing and thinning characteristics can be obtained. On the other hand, in Comparative Examples 1 and 3, the polishing rate of the barrier layer film (tantalum film) was reduced, and the polishing rate of the silicon dioxide film was considerably increased, so that the dishing and thinning characteristics were deteriorated. In Comparative Example 2, although the polishing rate of the barrier layer film (tantalum film) was high, the polishing rate of the silicon dioxide film was considerably high, so that dishing and thinning characteristics were deteriorated.
【００４７】[0047]
【発明の効果】本発明の導体用研磨液は、バリア層とし
て用いられるタンタルやタンタル合金及び窒化タンタル
やその他のタンタル化合物の研磨を可能にし、かつ銅合
金配線のディッシングとシニング及び研磨キズ発生を抑
制し、信頼性の高い金属膜の埋め込みパターン形成する
ことができる。The polishing slurry for conductors of the present invention enables polishing of tantalum, a tantalum alloy, tantalum nitride, and other tantalum compounds used as a barrier layer, and reduces dishing, thinning, and polishing scratches on copper alloy wiring. It is possible to suppress the formation and form a highly reliable buried pattern of the metal film.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｈ０１Ｌ 21/308 Ｈ０１Ｌ 21/306 Ｍ 21/3205 21/88 Ｋ (72)発明者 内田 剛 茨城県つくば市和台48番 日立化成工業株 式会社総合研究所内 (72)発明者 寺崎 裕樹 茨城県つくば市和台48番 日立化成工業株 式会社総合研究所内 Ｆターム(参考） 5F033 HH11 HH12 HH21 HH32 MM01 MM13 QQ50 WW00 WW01 WW04 XX01 5F043 AA26 BB18 DD16 EE08 FF07 GG03 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) H01L 21/308 H01L 21/306 M 21/3205 21/88 K (72) Inventor Go Uchida Tsukuba, Ibaraki Wada No. 48 Hitachi Chemical Co., Ltd. Research Institute (72) Inventor Hiroki Terazaki 48 No. 48 Wadai, Tsukuba, Ibaraki Prefecture Hitachi Chemical Co., Ltd. WW00 WW01 WW04 XX01 5F043 AA26 BB18 DD16 EE08 FF07 GG03
Claims (15)
保護膜形成剤、酸及び水を含有する研磨液であり、砥粒
が、一次粒子が平均２〜１０粒子凝集した平均粒径が７
０ｎｍ以下の２次粒子からなる粒子であることを特徴と
する導体用研磨液。1. A polishing liquid containing abrasive grains, an oxidizing agent for a conductor, an agent for forming a protective film for a metal surface, an acid and water, wherein the abrasive grains have an average particle diameter of 2 to 10 primary particles on average. 7
A polishing slurry for a conductor, which is a particle comprising secondary particles of 0 nm or less.
タニア、ジルコニア及びゲルマニアより選ばれた少なく
とも１種である請求項１記載の導体用研磨液。2. The conductor polishing slurry according to claim 1, wherein the abrasive grains are at least one selected from silica, alumina, ceria, titania, zirconia, and germania.
ルアルミナである請求項１記載の導体用研磨液。3. The conductor polishing liquid according to claim 1, wherein the abrasive grains are colloidal silica or colloidal alumina.
体の酸化剤の濃度が０．０１〜３重量％である請求項１
〜３何れか記載の導体用研磨液。4. The polishing liquid according to claim 1, wherein the pH of the polishing liquid is 3 or less, and the concentration of the oxidizing agent in the conductor is 0.01 to 3% by weight.
4. The polishing slurry for a conductor according to any one of items 3 to 3.
れか記載の導体用研磨液。5. The polishing slurry for a conductor according to claim 1, further comprising a water-soluble polymer.
はその塩、ポリメタクリル酸もしくはその塩、ポリアミ
ド酸もしくはその塩、ポリアクリルアミド、ポリビニル
アルコール及びポリビニルピロリドンからなる群から選
ばれた少なくとも１種である請求項５記載の導体用研磨
液。6. The water-soluble polymer is at least one selected from the group consisting of polyacrylic acid or a salt thereof, polymethacrylic acid or a salt thereof, polyamic acid or a salt thereof, polyacrylamide, polyvinyl alcohol and polyvinylpyrrolidone. The polishing slurry for a conductor according to claim 5.
重量％であり、導体のバリア層用である請求項１〜６何
れか記載の導体用研磨液。7. The conductor having an oxidizing agent concentration of 0.01 to 1.5.
The polishing slurry for a conductor according to any one of claims 1 to 6, which is used for a barrier layer of the conductor.
記載の導体用研磨液。8. The polishing slurry for a conductor according to claim 1, wherein the acid is an organic acid.
酸、グリコール酸及びクエン酸から選ばれた少なくとも
１種である請求項８記載の導体用研磨液。9. The polishing slurry for a conductor according to claim 8, wherein the organic acid is at least one selected from malonic acid, malic acid, tartaric acid, glycolic acid and citric acid.
ンゾトリアゾール及びその誘導体から選ばれた少なくと
も１種である請求項１〜９記載の導体用研磨液。10. The conductor polishing liquid according to claim 1, wherein the protective film forming agent for the metal surface is at least one selected from benzotriazole and derivatives thereof.
過ヨウ素酸カリウム、次亜塩素酸及びオゾン水より選ば
れた少なくとも１種である請求項１〜１０何れか記載の
導体用研磨液。11. The oxidizing agent for the conductor is hydrogen peroxide, nitric acid,
The polishing slurry for a conductor according to any one of claims 1 to 10, wherein the polishing slurry is at least one selected from potassium periodate, hypochlorous acid, and ozone water.
る導体である請求項１〜１１何れか記載の導体用研磨
液。12. The polishing slurry for a conductor according to claim 1, wherein the conductor is a conductor serving as a copper or copper alloy barrier layer.
が、タンタル、窒化タンタル、タンタル合金又はその他
のタンタル化合物である請求項１２記載の導体用研磨
液。13. The polishing slurry for a conductor according to claim 12, wherein the conductor serving as a copper or copper alloy barrier layer is tantalum, tantalum nitride, a tantalum alloy, or another tantalum compound.
磨液を用いて、タンタル、窒化タンタル、タンタル合金
又はその他のタンタル化合物からなる導体のバリア層を
研磨する研磨方法。14. A polishing method for polishing a barrier layer of a conductor made of tantalum, tantalum nitride, a tantalum alloy or another tantalum compound using the polishing slurry for a conductor according to claim 1.
磨液を用いて、銅又は銅合金とそのバリア層を含む面を
研磨する研磨方法。15. A polishing method for polishing a surface containing copper or a copper alloy and a barrier layer thereof using the polishing slurry for a conductor according to claim 1. Description:
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|---|---|---|---|
| JP2001063905A JP4224221B2 (en) | 2001-03-07 | 2001-03-07 | Polishing liquid for conductor and polishing method using the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001063905A JP4224221B2 (en) | 2001-03-07 | 2001-03-07 | Polishing liquid for conductor and polishing method using the same |
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|---|---|---|---|
| JP2008028775A Division JP4710915B2 (en) | 2008-02-08 | 2008-02-08 | Polishing method |
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|---|---|
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ID=18922816
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005268667A (en) * | 2004-03-19 | 2005-09-29 | Fujimi Inc | Polishing composition |
| JP2007005790A (en) * | 2005-06-22 | 2007-01-11 | Samsung Electronics Co Ltd | Etchant, method for forming wiring using this, and method for manufacturing thin film transistor substrate |
| JP2007095843A (en) * | 2005-09-27 | 2007-04-12 | Fujifilm Corp | Polishing method |
| US7378349B2 (en) | 2004-04-12 | 2008-05-27 | Jsr Corporation | Chemical mechanical polishing aqueous dispersion and chemical mechanical polishing method |
| KR101345555B1 (en) * | 2005-07-12 | 2013-12-27 | 삼성코닝정밀소재 주식회사 | Compositon of slurry |
-
2001
- 2001-03-07 JP JP2001063905A patent/JP4224221B2/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005268667A (en) * | 2004-03-19 | 2005-09-29 | Fujimi Inc | Polishing composition |
| KR101141178B1 (en) | 2004-03-19 | 2012-05-02 | 가부시키가이샤 후지미인코퍼레이티드 | Polishing composition and polishing method |
| US7378349B2 (en) | 2004-04-12 | 2008-05-27 | Jsr Corporation | Chemical mechanical polishing aqueous dispersion and chemical mechanical polishing method |
| JP2007005790A (en) * | 2005-06-22 | 2007-01-11 | Samsung Electronics Co Ltd | Etchant, method for forming wiring using this, and method for manufacturing thin film transistor substrate |
| KR101345555B1 (en) * | 2005-07-12 | 2013-12-27 | 삼성코닝정밀소재 주식회사 | Compositon of slurry |
| JP2007095843A (en) * | 2005-09-27 | 2007-04-12 | Fujifilm Corp | Polishing method |
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