JP2006196508A - Cmp polishing solution for semiconductor metal film, and polishing method of substrate - Google Patents
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本発明は、化学機械研磨（以下、ＣＭＰという）用研磨液及び基体の研磨方法に関するものである。更に詳しくは、あらかじめ溝を形成した基体（基板）上にバリアメタルを堆積し、更に上記溝に金属を埋め込む半導体デバイスの配線工程の後、バリアメタルの除去工程で用いる半導体金属膜用CMP研磨液とこの研磨液を用いた基体の研磨方法とに関するものである。 The present invention relates to a polishing liquid for chemical mechanical polishing (hereinafter referred to as CMP) and a method for polishing a substrate. More specifically, a CMP metal polishing liquid for a semiconductor metal film used in a barrier metal removal step after a wiring step of a semiconductor device in which a barrier metal is deposited on a substrate (substrate) on which a groove has been formed in advance and a metal is embedded in the groove. And a method for polishing a substrate using this polishing liquid.
近年、半導体集積回路（以下、ＬＳＩと略す）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。ＣＭＰ法はその一つであり、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、金属プラグの形成、埋め込み配線の形成等において頻繁に利用される技術である（特許文献１参照）。 In recent years, new microfabrication techniques have been developed along with higher integration and higher performance of semiconductor integrated circuits (hereinafter abbreviated as LSI). The CMP method is one of them, and is a technique that is frequently used in the LSI manufacturing process, in particular, the flattening of the interlayer insulating film, the formation of the metal plug, the formation of the embedded wiring in the multilayer wiring forming process (Patent Document 1). reference).
また、最近は、ＬＳＩを高性能化するために、配線材料として従来のアルミニウム合金に代わって銅合金も使われ始めている。しかし、銅合金はアルミニウム合金配線の形成で用いられるドライエッチング法による微細加工が困難であるため、あらかじめ溝を形成した基体上に銅合金薄膜を堆積して埋め込み、溝部以外の銅合金薄膜をＣＭＰにより除去して埋め込み配線を形成する方法（いわゆる、ダマシン法）が主として採用されている。ダマシン法については、例えば、特許文献２に開示がある。なお、銅合金薄膜をあらかじめ溝を形成した基体(SiO2)上に堆積して埋め込む前に、銅合金のSiO2中への拡散防止、銅合金／SiO2間の密着力確保のために、TaN、Ta等のバリアメタルが形成される。 Recently, copper alloys have begun to be used as wiring materials in place of conventional aluminum alloys in order to improve the performance of LSIs. However, since copper alloy is difficult to be finely processed by the dry etching method used in forming aluminum alloy wiring, a copper alloy thin film is deposited and embedded on a substrate on which a groove has been formed in advance, and the copper alloy thin film other than the groove is CMPed. A method (so-called damascene method) in which buried wiring is formed by removing by the above method is mainly employed. The damascene method is disclosed in Patent Document 2, for example. Before depositing and embedding a copper alloy thin film on a substrate (SiO 2 ) in which grooves are formed in advance, in order to prevent diffusion of the copper alloy into SiO 2 and to ensure the adhesion between the copper alloy / SiO 2 , A barrier metal such as TaN or Ta is formed.
金属をＣＭＰ法で平坦化する一般的な方法は、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潤し、基体の金属膜形成面を押し付けて、その裏面から所定の圧力（以下、研磨圧力という）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金属膜の凸部を除去するものである。
ＣＭＰに用いられる金属用研磨液は、通常は固体砥粒及び酸化剤からなっており、先ず、酸化によって金属膜表面を酸化し、その酸化層を固体砥粒によって削り取ると考えられている。金属表面の凹部の酸化層では研磨パッドにあまり触れず、固体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体表面は平坦化される（非特許文献１参照）。
A general method for planarizing metal by CMP is to apply a polishing pad on a circular polishing platen (platen), moisten the polishing pad surface with a metal polishing liquid, and press the metal film forming surface of the substrate. In this state, the polishing platen is turned with a predetermined pressure (hereinafter referred to as polishing pressure) applied from the back surface, and the convex portion of the metal film is removed by mechanical friction between the polishing liquid and the convex portion of the metal film. .
The metal polishing liquid used for CMP is usually composed of solid abrasive grains and an oxidizing agent. It is considered that the metal film surface is first oxidized by oxidation and the oxidized layer is scraped off by solid abrasive grains. Since the oxide layer in the concave portion on the metal surface does not touch the polishing pad so much and the effect of scraping with solid abrasive grains does not reach, the metal layer on the convex portion is removed with the progress of CMP, and the substrate surface is flattened (non-patent) Reference 1).
ＣＭＰ法における研磨速度を高める方法の一つとして、研磨液にグリシン等のアミノ酢酸又はアミド硫酸からなる金属酸化物溶解剤を配合する方法が知られている（特許文献３）。固体砥粒によって削り取られた金属酸化物を金属酸化物溶解剤の作用で溶解させると砥粒による削り取りの効果が増すためと説明されている。ただ、凹部における金属膜表面の酸化層も溶解（エッチング）されて金属膜表面が露出すると、その金属膜表面が酸化剤によってさらに酸化され、これが繰り返されると凹部における金属膜のエッチングが進行し、平坦化効果が損なわれる。これを防ぐために、研磨液に更にベンゾトリアゾール等のエッチング防止剤（保護膜形成剤）を配合している（特許文献３）。 As one method for increasing the polishing rate in the CMP method, a method is known in which a metal oxide solubilizer composed of aminoacetic acid or amide sulfuric acid such as glycine is blended in the polishing liquid (Patent Document 3). It is described that the metal oxide scraped by the solid abrasive grains is dissolved by the action of the metal oxide solubilizing agent, so that the effect of scraping by the abrasive grains is increased. However, when the oxide layer on the surface of the metal film in the recess is also dissolved (etched) and the surface of the metal film is exposed, the surface of the metal film is further oxidized by the oxidizing agent, and when this is repeated, the etching of the metal film in the recess proceeds. The flattening effect is impaired. In order to prevent this, an etching inhibitor (protective film forming agent) such as benzotriazole is further blended in the polishing liquid (Patent Document 3).
溝部以外の銅合金薄膜をCMP研磨液により除去した後、従来のバリアメタル用CMP研磨液を用いて、TaNまたはTaのバリアメタルを研磨して除去し、更にバリアメタルの残渣を除去するために、基体のSiO2を研磨する場合には、次のような問題が起こりやすい。
（１）溝部の銅合金薄膜近傍のTaNまたはTaのバリアメタルおよびSiO2が、それ以外のSiO2より深く削れる現象(Fang)が発生する。このFangは、配線の短絡の要因となりLSIの製造歩留まりを低下させる原因となる。
To remove the copper alloy thin film other than the grooves with CMP polishing liquid, then polish and remove TaN or Ta barrier metal using conventional CMP polishing liquid for barrier metal, and further remove the barrier metal residue When polishing the substrate SiO 2 , the following problems are likely to occur.
(1) A phenomenon (Fang) occurs in which the TaN or Ta barrier metal and SiO 2 near the copper alloy thin film in the groove are deeper than other SiO 2 . This Fang causes a short circuit of the wiring and causes a decrease in the manufacturing yield of the LSI.
本発明の目的は、TaNまたはTaのバリアメタルおよび基体のSiO2を連続して研磨可能であり、この際に、銅合金薄膜近傍のTaNまたはTaのバリアメタルおよびSiO2が、それ以外のSiO2より深く削れる現象(Fang)を抑制できるCMP用研磨液を提供することであり、また、これを用いた基体の研磨方法を提供することである。 The object of the present invention is to be able to continuously polish TaN or Ta barrier metal and SiO 2 of the substrate. At this time, TaN or Ta barrier metal and SiO 2 in the vicinity of the copper alloy thin film are made of other SiO 2. 2 is to provide a CMP polishing liquid capable of suppressing a phenomenon (Fang) that can be cut deeper, and to provide a method for polishing a substrate using the same.
上記課題を達成するために、本発明者らは、種々検討していたところ、次の（i）を見出し、本発明を完成することができた。
(i)電気泳動法により測定したゼータ電位が5mV以上であるシリカ粒子、酸化剤、金属表面に対する保護膜形成剤、酸および水を含有する半導体金属膜用CMP研磨液で、溝部に銅配線薄膜を形成した基体のTaNおよびSiO2を連続研磨すると、溝部の銅合金薄膜近傍のTaNおよびSiO2が、それ以外のSiO2より深く削れる現象(Fang)が抑制されたこと。
In order to achieve the above-mentioned problems, the present inventors have made various studies and found the following (i) to complete the present invention.
(i) CMP polishing liquid for semiconductor metal film containing silica particles having an zeta potential measured by electrophoresis of 5 mV or more, an oxidizing agent, a protective film forming agent for metal surfaces, acid and water, and a copper wiring thin film in the groove When TaN and SiO 2 of the substrate on which the substrate was formed were continuously polished, the phenomenon (Fang) in which TaN and SiO 2 in the vicinity of the copper alloy thin film in the groove portion were deeply cut away from other SiO 2 was suppressed.
本発明は、電気泳動法により測定したゼータ電位が5mV以上であるシリカ粒子、酸化剤、金属表面に対する保護膜形成剤、酸および水を含有する半導体金属膜用CMP研磨液 に関する。
また、本発明は、あらかじめ溝を形成した基体（基板）上にバリアメタルを堆積し、更にこの溝に金属を埋め込む半導体デバイスの配線工程の後、バリアメタルを研磨除去したとき、金属配線上部に対する金属配線近傍のバリアメタルおよびSiO2の膜減り(Fang)量が20nm以下である前記記載の半導体金属膜用CMP研磨液に関する。
また、本発明は、半導体集積回路における導体埋め込み配線形成後に、前記研磨液を用いて、TaNまたはTaのバリアメタルを除去し、更に、バリアメタルの残渣を完全に除去するために、バリアメタルの下地のSiO2を研磨することを順に行うことを特徴とする基体の研磨方法に関する。
The present invention relates to a CMP polishing liquid for a semiconductor metal film containing silica particles having an zeta potential measured by electrophoresis of 5 mV or more, an oxidizing agent, a protective film forming agent for a metal surface, an acid and water.
Further, according to the present invention, when a barrier metal is deposited on a substrate (substrate) in which a groove is formed in advance, and the barrier metal is polished and removed after the wiring process of the semiconductor device in which the metal is embedded in the groove, The present invention relates to the CMP polishing liquid for a semiconductor metal film according to the above, wherein the film thickness (Fang) of the barrier metal and SiO 2 near the metal wiring is 20 nm or less.
The present invention also provides a method for removing TaN or Ta barrier metal after the formation of a buried conductor wiring in a semiconductor integrated circuit and further removing the barrier metal residue completely. The present invention relates to a method for polishing a substrate, characterized by sequentially performing polishing of underlying SiO 2 .
本発明の研磨液を用いることにより、TaNまたはTaのバリアメタルおよび基体のSiO2を連続して研磨可能であり、銅配線近傍のTaNまたはTaのバリアメタルおよびSiO2が、それ以外のSiO2より深く削れる現象(Fang)の発生を抑制できる By using the polishing liquid of the present invention, TaN or Ta barrier metal and SiO 2 of the substrate can be continuously polished, and TaN or Ta barrier metal and SiO 2 in the vicinity of the copper wiring are made of other SiO 2. Can suppress the phenomenon of deeper cutting (Fang)
更に本発明を詳しく説明する。
本発明で、削りとられる金属膜は、TaNまたはTaおよびこれらを積層した金属層を有する堆積膜からなる金属膜、並びにその下地のSiO2である。
Further, the present invention will be described in detail.
In the present invention, the metal film to be scraped is TaN or Ta and a metal film made of a deposited film having a metal layer obtained by laminating these and SiO 2 as an underlying layer.
本発明において、研磨液で用いる砥粒としては、電気泳動法により測定したゼータ電位が5mV以上であるシリカ粒子である。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）の発生数が少ない点で、コロイダルシリカが好ましい。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り製造できる。 In the present invention, the abrasive grains used in the polishing liquid are silica particles whose zeta potential measured by electrophoresis is 5 mV or more. Colloidal silica is preferable in that it has good dispersion stability in the polishing liquid and the number of polishing scratches (scratches) generated by CMP is small. Colloidal silica can be produced by hydrolysis of silicon alkoxide or ion exchange of sodium silicate.
研磨液中における砥粒の濃度は、1.0〜15.0重量％の範囲が好ましく、2.0〜12.0重量％の範囲が更に好ましい。1.0重量％未満では、SiO2研磨速度が＜500Å／minに遅くなる傾向がある。また、15.0重量％を超えると、TaN、Ta、SiO2研磨速度の増加は、わずかであり、それ以上加えても余り意味がない。 The concentration of the abrasive grains in the polishing liquid is preferably in the range of 1.0 to 15.0% by weight, and more preferably in the range of 2.0 to 12.0% by weight. If it is less than 1.0% by weight, the SiO 2 polishing rate tends to be as low as <500 mm / min. On the other hand, if it exceeds 15.0% by weight, the increase in TaN, Ta, and SiO 2 polishing rate is slight, and adding more than that is not meaningful.
本発明において、砥粒のゼータ電位を調整するために、シランカップリング剤を用いることができる。本発明において研磨液に用いるシランカップリング剤に制限はないが、アミノ基を含むN-β(アミノエチル)γ-アミノプロピルメチルジメトキシシラン、N-β(アミノエチル)γ-アミノプロピルトリメトキシシラン、N-β(アミノエチル)γ-アミノプロピルトリエトキシシラン、γ-アミノプロピルトリメトキシシラン、γ-アミノプロピルトリエトキシシランが好ましい。シランカップリング剤の配合量は、砥粒のゼータ電位を5mV以上にするのであれば、特に制限はない。また、砥粒のゼータ電位を調整するものとしては、シランカップリング剤に限定するものではない。 In the present invention, a silane coupling agent can be used to adjust the zeta potential of the abrasive grains. There is no limitation on the silane coupling agent used in the polishing liquid in the present invention, but N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane containing amino groups N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane are preferred. The amount of the silane coupling agent is not particularly limited as long as the zeta potential of the abrasive grains is 5 mV or more. Moreover, as what adjusts the zeta potential of an abrasive grain, it is not limited to a silane coupling agent.
本発明において、研磨液に用いる酸化剤としては、過酸化水素（Ｈ２Ｏ２）、硝酸、過ヨウ素酸カリウム、次亜塩素酸、オゾン水等があり、その中でも過酸化水素が好ましい。基体が集積回路用素子を含むシリコン基板である場合は、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を避けるため、不揮発成分を含まない酸化剤が好ましい。また、オゾン水は組成の時間変化が激しいので注意を要する。なお、適用対象の基体が半導体素子を含まないガラス基板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。 In the present invention, the oxidizing agent used in the polishing liquid includes hydrogen peroxide (H 2 O 2 ), nitric acid, potassium periodate, hypochlorous acid, ozone water, etc. Among them, hydrogen peroxide is preferable. When the substrate is a silicon substrate including an integrated circuit element, an oxidizing agent that does not contain a nonvolatile component is preferable in order to avoid contamination with alkali metal, alkaline earth metal, halide, and the like. In addition, attention is required because ozone water has a severe compositional change over time. Note that when the substrate to be applied is a glass substrate that does not include a semiconductor element, an oxidizing agent that includes a nonvolatile component may be used.
酸化剤の配合量は、研磨液の総量１００ｇに対して、０．０００３０〜０．００８０ｍｏｌとすることが好ましく、０．０００３５〜０．００６０ｍｏｌとすることが更に好ましく、０．０００５０〜０．００３０ｍｏｌとすることが特に好ましい。０．０００３０ｍｏｌ未満では、TaNまたはTa研磨速度が遅くなる傾向となり、０．００８０ｍｏｌを超えると、銅合金薄膜の研磨速度が速くなり、目減りが激しくなる傾向となる。 The blending amount of the oxidizing agent is preferably 0.00030 to 0.0080 mol, more preferably 0.00035 to 0.0060 mol, and more preferably 0.00050 to 0.0030 mol with respect to 100 g of the total amount of the polishing liquid. It is particularly preferable that If it is less than 0.00030 mol, the TaN or Ta polishing rate tends to be slow, and if it exceeds 0.0080 mol, the polishing rate of the copper alloy thin film becomes high and the loss tends to be severe.
本発明において、金属の保護膜形成剤としては、ベンゾトリアゾール(ＢＴＡ)、ＢＴＡ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)、カルボキシル基で置換したもの（ベンゾトリアゾール−４−カルボン酸）、前期カルボキシル基で置換したもののカルボキシル基の水素原子をエチル基、プロピル基、ブチル基又はオクチル基で置換したもの、あるいは、ナフトトリアゾール、ナフトトリアゾール誘導体等がある。さらに、金属の保護膜形成剤として、7-ヒドロキシ-5-メチル-(2,3a)-トリアゾロピリミジンがある。 In the present invention, metal protective film forming agents include benzotriazole (BTA), BTA derivatives, for example, one hydrogen atom of a benzene ring of BTA substituted with a methyl group (tolyltriazole), one substituted with a carboxyl group (Benzotriazole-4-carboxylic acid), those in which the hydrogen atom of the carboxyl group has been substituted with a carboxyl group in the previous period, or those in which the ethyl group, propyl group, butyl group or octyl group are substituted, or naphthotriazole, naphthotriazole derivatives, etc. . Furthermore, 7-hydroxy-5-methyl- (2,3a) -triazolopyrimidine is used as a metal protective film forming agent.
研磨液におけるベンゾトリアゾール又はベンゾトリアゾール誘導体（保護膜形成剤）の配合量は、研磨液の総量１００ｇに対して０．０００１〜０．０５ｍｏｌとすることが好ましく、０．０００３〜０．００５ｍｏｌとすることが更に好ましく、０．０００５〜０．００３５ｍｏｌとすることが特に好ましい。０．０００１ｍｏｌ未満では、銅配線のエッチングの抑制が困難となる傾向になり、０．０５ｍｏｌを超えると、TaNまたはTaの研磨速度が低下する傾向になる。 The blending amount of benzotriazole or benzotriazole derivative (protective film forming agent) in the polishing liquid is preferably 0.0001 to 0.05 mol, and 0.0003 to 0.005 mol with respect to 100 g of the total amount of the polishing liquid. Is more preferable, and 0.0005 to 0.0035 mol is particularly preferable. If it is less than 0.0001 mol, it tends to be difficult to suppress etching of the copper wiring, and if it exceeds 0.05 mol, the polishing rate of TaN or Ta tends to decrease.
また、研磨液における7-ヒドロキシ-5-メチル-(2,3a)-トリアゾロピリミジンの配合量は、研磨液の総量１００ｇに対して０．００００1〜０．００５ｍｏｌとすることが好ましく、０．００００３〜０．０００５０ｍｏｌとすることが更に好ましく、０．００００５〜０．０００３０ｍｏｌとすることが特に好ましい。０．００００１ｍｏｌ未満では、銅配線のエッチングの抑制が困難となる傾向になり、０．００５ｍｏｌを超えると、TaNまたはTaの研磨速度が低下する傾向になる。 The blending amount of 7-hydroxy-5-methyl- (2,3a) -triazolopyrimidine in the polishing liquid is preferably 0.00001 to 0.005 mol with respect to 100 g of the total amount of the polishing liquid. It is more preferable to set it as 0.0003-0.00050 mol, and it is especially preferable to set it as 0.00005-0.00030 mol. If it is less than 0.00001 mol, it tends to be difficult to suppress etching of the copper wiring, and if it exceeds 0.005 mol, the polishing rate of TaN or Ta tends to decrease.
金属の保護膜形成剤としては、ベンゾトリアゾール(ＢＴＡ)、ＢＴＡ誘導体、7-ヒドロキシ-5-メチル-(2,3a)-トリアゾロピリミジンのうち、何れか1つを用いるのが好ましい。 As the metal protective film forming agent, any one of benzotriazole (BTA), a BTA derivative, and 7-hydroxy-5-methyl- (2,3a) -triazolopyrimidine is preferably used.
本発明の酸としては、ギ酸、酢酸、プロピオン酸、酪酸、吉草酸、２−メチル酪酸、ｎ−ヘキサン酸、３，３−ジメチル酪酸、２−エチル酪酸、４−メチルペンタン酸、ｎ−ヘプタン酸、２−メチルヘキサン酸、ｎ−オクタン酸、２−エチルヘキサン酸、安息香酸、グリコ−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、又はこれら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、塩化アンモニウム等、クロム酸等がある。これらの中では、実用的な研磨速度が得られる点で、サリチル酸、リンゴ酸、酒石酸、クエン酸又はグリコール酸が好ましく用いられる。 Examples of the acid of the present invention include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, and n-heptane. Acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, Maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, etc., or salts such as ammonium salts of these organic acids, sulfuric acid, nitric acid, ammonia, ammonium salts such as ammonium persulfate, ammonium nitrate, ammonium chloride, chromic acid, etc. is there. Among these, salicylic acid, malic acid, tartaric acid, citric acid or glycolic acid is preferably used in that a practical polishing rate can be obtained.
研磨液で用いる酸の配合量は、研磨液の総量１００ｇに対して０〜０．０１０ｍｏｌとすることが好ましく、０．００００５〜０．００７５ｍｏｌとすることが更に好ましく、０．０００１〜０．００５０ｍｏｌとすることが特に好ましい。酸の配合量が０．０１０ｍｏｌを超えると、銅配線のエッチングの抑制が困難となる傾向になる。 The amount of the acid used in the polishing liquid is preferably 0 to 0.010 mol, more preferably 0.00005 to 0.0075 mol, and more preferably 0.0001 to 0.0050 mol with respect to 100 g of the total amount of the polishing liquid. It is particularly preferable that When the compounding amount of the acid exceeds 0.010 mol, it becomes difficult to suppress the etching of the copper wiring.
本発明の基体の研磨方法は、先に述べたように、電気泳動法により測定したゼータ電位が5mV以上であるシリカ粒子、酸化剤、金属表面に対する保護膜形成剤、酸および水を含有する半導体金属膜用CMP研磨液を用いて、TaNまたはTaのバリアメタルを除去し、更に、バリアメタルの残渣を除去するためにバリアメタルの下地のSiO2を順に連続して研磨することを特徴としている。 As described above, the substrate polishing method of the present invention includes a silica particle having an zeta potential measured by electrophoresis of 5 mV or more, an oxidizing agent, a protective film forming agent for metal surfaces, a semiconductor containing acid and water. It is characterized by removing TaN or Ta barrier metal using CMP polishing liquid for metal film, and further polishing the underlying SiO 2 of the barrier metal successively in order to remove the barrier metal residue. .
基体側では表面に凹部が設けられて、その上に銅又は銅合金（銅／クロム等）を含む金属膜が形成・充填されている。それ以外の部分には、TaNまたはTaのバリアメタルが形成されている。このバリアメタルとその下地のSiO2の一部を本発明の研磨方法で研磨すると、前記凹部に金属膜を残して、所望の導体パターンが得られる。 On the substrate side, a recess is provided on the surface, and a metal film containing copper or a copper alloy (copper / chromium or the like) is formed and filled thereon. In other parts, TaN or Ta barrier metal is formed. When this barrier metal and a part of the underlying SiO 2 are polished by the polishing method of the present invention, a desired conductor pattern can be obtained leaving the metal film in the recess.
基体の研磨は、研磨定盤の研磨布上に本発明に係る研磨液を供給しながら、金属堆積膜を有する基体（基板）を研磨布に押圧した状態で、研磨定盤と基体との相対的位置を動かすことによって行うことができる。 The polishing of the substrate is performed by supplying the polishing liquid according to the present invention onto the polishing cloth of the polishing surface plate, while pressing the substrate (substrate) having the metal deposition film against the polishing cloth, relative to the polishing surface plate and the substrate. This can be done by moving the target position.
以下、実施例により、本発明を更に具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples.
（１）研磨液の調製
研磨液1の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシリカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、シランカップリング剤を０．００２５重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６７７５重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、7.8mVであった。
研磨液２の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシリカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、シランカップリング剤を０．００５０重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６７５０重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、8.2mVであった。
研磨液３の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシリカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、シランカップリング剤を０．０１０重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６７重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、12.7mVであった。
研磨液４の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシリカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６８重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、0.5mVであった。
研磨液５の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシリカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、シランカップリング剤を０．００１重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６７９０重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、2.9mVであった。
研磨液６の調製
アンモニア水溶液中で、テトラエトキシシランの加水分解により製造したコロイダルシ リカを６．０重量部、ベンゾトリアゾールを０．２重量部、サリチル酸を０．１２重量部、シランカップリング剤を０．００５重量部、プロピレングリコール モノ プロピルエーテルを８．０重量部、純水を８５．６７５０重量部取り、よく攪拌・混合した。次に、この混合液と過酸化水素(試薬特級、３０％水溶液)とを９９．８０：０．２０の重量比率で混合し、研磨液とした。この研磨液中の砥粒のゼータ電位をMALVERN社製のゼータ電位測定装置ZETASIZER3000HSAで測定した結果、4.3mVであった。
(1) Preparation of polishing liquid Preparation of polishing liquid 1 In an aqueous ammonia solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, and 0.12 parts by weight of salicylic acid Parts, 0.0025 parts by weight of the silane coupling agent, 8.0 parts by weight of propylene glycol monopropyl ether, and 85.6775 parts by weight of pure water were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and as a result, it was 7.8 mV.
Preparation of polishing liquid 2 In an aqueous ammonia solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, 0.12 parts by weight of salicylic acid, and a silane coupling agent 0.0050 parts by weight, propylene glycol monopropyl ether 8.0 parts by weight, and pure water 85.6750 parts by weight were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and found to be 8.2 mV.
Preparation of polishing liquid 3 In an aqueous ammonia solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, 0.12 parts by weight of salicylic acid, and a silane coupling agent 0.010 parts by weight, 8.0 parts by weight of propylene glycol monopropyl ether, and 85.67 parts by weight of pure water were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and as a result, it was 12.7 mV.
Preparation of polishing liquid 4 In ammonia aqueous solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, 0.12 parts by weight of salicylic acid, propylene glycol monopropyl ether 8.0 parts by weight and 85.68 parts by weight of pure water were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and as a result, it was 0.5 mV.
Preparation of polishing liquid 5 In an aqueous ammonia solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, 0.12 parts by weight of salicylic acid, and a silane coupling agent 0.001 part by weight, 8.0 parts by weight of propylene glycol monopropyl ether and 85.6790 parts by weight of pure water were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and as a result, it was 2.9 mV.
Preparation of polishing liquid 6 In an aqueous ammonia solution, 6.0 parts by weight of colloidal silica produced by hydrolysis of tetraethoxysilane, 0.2 parts by weight of benzotriazole, 0.12 parts by weight of salicylic acid, and a silane coupling agent 0.005 parts by weight, 8.0 parts by weight of propylene glycol monopropyl ether, and 85.6750 parts by weight of pure water were taken and mixed well. Next, this mixed solution and hydrogen peroxide (special grade reagent, 30% aqueous solution) were mixed at a weight ratio of 99.80: 0.20 to obtain a polishing solution. The zeta potential of the abrasive grains in this polishing liquid was measured with a zeta potential measuring device ZETASIZER3000HSA manufactured by MALVERN, and as a result, it was 4.3 mV.
（２）研磨条件
銅配線付き基体：表面のSiO2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２５ｎｍのTaN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み、溝部以外の銅膜を銅用研磨液を用いて公知のＣＭＰ法により研磨除去したシリコン基板。この基板の配線金属部幅１００μｍ、絶縁膜部幅１００μｍが交互に並んだストライプ状パターン部の触針式段差計による表面形状から、絶縁膜部に対する銅配線金属部の膜減り(Dishing)量は、６０nmであった。
研磨パッド：独立気泡を持つ発泡ポリウレタン樹脂を用いた。
研磨圧力：１４０ｇｆ／ｃｍ２
基体と研磨定盤との相対速度：１００ｍ／ｍｉｎ
研磨時間：研磨後の絶縁膜部膜厚が、450nmとなるように、研磨時間を設定した。
(2) Polishing conditions Substrate with copper wiring: A groove having a depth of 0.5 μm is formed in SiO 2 on the surface, and a TaN film having a thickness of 25 nm is formed as a barrier layer by a known sputtering method. A silicon substrate in which a copper film is formed by burying by a known heat treatment and the copper film other than the groove is polished and removed by a known CMP method using a copper polishing liquid. From the surface shape of the striped pattern portion in which the wiring metal portion width of 100 μm and the insulating film portion width of 100 μm are alternately arranged by the stylus type step meter, the amount of film reduction of the copper wiring metal portion relative to the insulating film portion is , 60 nm.
Polishing pad: A foamed polyurethane resin having closed cells was used.
Polishing pressure: 140 gf / cm 2
Relative speed between substrate and polishing surface plate: 100 m / min
Polishing time: The polishing time was set so that the film thickness of the insulating film after polishing was 450 nm.
（３）研磨品の評価方法
Fang量：銅配線付き基体を用いて研磨を行い、触針式段差計で配線金属部幅１００μｍ、絶縁膜部幅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、銅配線上部に対する銅配線近傍のTaNおよびSiO2の膜減り量をFang量とした。
（４）研磨結果
(3) Polished product evaluation method
Fang amount: Polishing using a substrate with copper wiring, and using a stylus-type step gauge, the copper from the surface shape of the striped pattern part in which the wiring metal part width of 100 μm and the insulating film part width of 100 μm are arranged alternately The amount of TaN and SiO 2 film loss in the vicinity of the wiring was defined as the Fang amount.
(4) Polishing result
本発明の研磨液1〜3は、TaNおよび基体のSiO2を連続して研磨可能であり、比較例の研磨液4〜6に比較して、Fang量が小さく良好であることがわかる。
It can be seen that the polishing liquids 1 to 3 of the present invention can continuously polish TaN and the SiO 2 of the substrate, and the Fang amount is small and good as compared with the polishing liquids 4 to 6 of the comparative example.
Claims (3)
The substrate on which the film to be polished is formed is pressed against the polishing cloth of the polishing platen and pressed, and the CMP polishing liquid for semiconductor metal film according to claim 1 is supplied between the polishing film and the polishing cloth. And polishing method of the substrate to polish the film to be polished by moving the polishing platen.
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| JP5263400B2 (en) * | 2009-08-19 | 2013-08-14 | 日立化成株式会社 | CMP polishing liquid and polishing method |
| JP2013055342A (en) * | 2009-08-19 | 2013-03-21 | Hitachi Chemical Co Ltd | Cmp polishing liquid and polishing method |
| JP2014140056A (en) * | 2009-08-19 | 2014-07-31 | Hitachi Chemical Co Ltd | Cmp polishing liquid and polishing method |
| US8883031B2 (en) | 2009-08-19 | 2014-11-11 | Hitachi Chemical Company, Ltd. | CMP polishing liquid and polishing method |
| CN105070657A (en) * | 2009-08-19 | 2015-11-18 | 日立化成株式会社 | Polishing solution for cmp and polishing method |
| US9318346B2 (en) | 2009-08-19 | 2016-04-19 | Hitachi Chemical Company, Ltd. | CMP polishing liquid and polishing method |
| JP2013055343A (en) * | 2009-08-19 | 2013-03-21 | Hitachi Chemical Co Ltd | Cmp polishing liquid and polishing method |
| WO2011021599A1 (en) * | 2009-08-19 | 2011-02-24 | 日立化成工業株式会社 | Polishing solution for cmp and polishing method |
| JP7375483B2 (en) | 2019-11-15 | 2023-11-08 | Jsr株式会社 | Chemical mechanical polishing composition and chemical mechanical polishing method |
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