JP3875155B2 - Roll-off reducing agent - Google Patents

Description

【００５８】
表１の結果より、本発明のロールオフ低減剤を含有した実施例１〜６の基準研磨液組成物ではいずれも、比較例の-123mVに対して、特定表面電位が-110〜250mV に制御されることがわかる。
【００５９】
実施例７〜１５及び比較例２〜４
〔研磨用研磨液組成物配合方法〕
一次粒径の平均粒径0.23μm 、二次粒子の平均粒径0.65μm のα−アルミナ（純度約99.9％）16重量部、θ−アルミナ（平均粒径0.22μm 、比表面積150m²/g 、純度約99.9% ）を4 重量部、他の添加物として表２〜３に記載のロールオフ低減剤、化合物群（Ａ）や化合物群（Ｂ）を所定量、イオン交換水（残部）とを混合・攪拌し、研磨液組成物１００重量部を得た。
【００６０】
研磨方法
得られた研磨液組成物をイオン交換水で３倍希釈（vol/vol ）し、ランク・テーラーホブソン社製のタリーステップ（触針先端サイズ：25μm ×25μm 、ハイパスフィルター：80μm 、測定長さ：0.64mm）によって測定した中心線平均粗さRaが0.2 μm 、厚さ1.27 mm 、直径3.5 インチ（直径95.0 mm)のNi-Pメッキされたアルミニウム合金からなる基板の表面を両面加工機により、以下の両面加工機の設定条件でポリッシングし、磁気記録媒体用基板として用いられるNi-Pメッキされたアルミニウム合金基板の研磨物を得た。
両面加工機の設定条件を下記に示す。
【００６１】
＜両面加工機の設定条件＞
両面加工機：スピードファーム（株）製、9B型両面加工機
加工圧力：9.8kPa
研磨パッド：フジボウ（株）製、Ｈ９９００（商品名）
定盤回転数：30rpm
研磨液組成物希釈品供給流量：125ml/min
研磨時間：3.5min
投入した基板の枚数：10枚
【００６２】
〔研磨速度〕
研磨前後の各基板の重さを計り（Sartorius 社製、商品名：BP-210S ）を用いて測定し、各基板の重量変化を求め、１０枚の平均値を減少量とし、それを研磨時間で割った値を重量減少速度とした。重量の減少速度を下記の式に導入し、研磨速度（μm/min ）に変換した。実施例７〜１３は、比較例２の研磨速度を、実施例１４、１５及び比較例４は、比較例３の研磨速度をそれぞれ基準値１として各実験例の研磨速度の相対値（相対速度）を求めた。

【００６３】
〔ロールオフ〕
Zygo社製、Maxim 3D5700（商品名）を用いて以下の条件で測定した。
レンズ：Fizeau ×10
解析ソフト：Zygo Metro Pro（商品名）
上記の装置を用いて、ディスク中心から41.5mmから47.0mmまでのディスク端部の形状を測定し、図１のように、Ａ、Ｂ及びＣ点の位置をディスク中心からそれぞれ41.5mm、47mm及び43mmにとり、解析ソフトを用いて前記測定方法により、Ｄ（ベースラインとＢ点との位置の差）を求めた。この求められたＤを研磨前後のディスク研磨量の１／２で除した値をロールオフ値とした。
【００６４】
表２に比較例２の測定値を基準値１としたとき、表３に比較例３の測定値を基準値１としたときの相対速度、相対ロールオフ値をそれぞれ示す。
【００６５】
【表２】

【００６６】
【表３】

【００６７】
表２、３の結果より、研磨液組成物に本発明のロールオフ低減剤を添加することで（実施例７〜１５）、ロールオフ低減剤を添加しない場合に比べ（比較例２〜４）、研磨速度を低下することなくロールオフを低減できることがわかる。
また、比較例３と実施例１４の比較より、数種の有機酸を混合しても、本発明の表面電位を抑制するロールオフ低減剤を添加することで、研磨速度を低下することなくロールオフを低減することができることがわかる。
【００６８】
【発明の効果】
本発明のロールオフ低減剤、ロールオフ低減剤を含有するロールオフ低減剤組成物を精密部品用基板等の研磨に用いることにより、該基板のロールオフを著しく低減させる効果が奏される。
【図面の簡単な説明】
【図１】図１は、測定曲線とロールオフとの関係を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roll-off reducing agent in a polishing process and a polishing liquid composition using the same. Furthermore, it is related with the manufacturing method of the board | substrate using this polishing liquid composition, and the roll-off reduction method in a grinding | polishing process.
[0002]
[Prior art]
Hard disks are increasingly demanded for technologies that promote higher capacity. As one of the effective means for increasing the capacity, it is desired that the roll-off (the edge of the substrate to be polished) generated in the polishing process can be reduced and the recording can be performed to the outer periphery. In order to manufacture such a substrate with reduced roll-off, mechanical conditions such as hardening the polishing pad and reducing the polishing load have been studied. However, although such mechanical polishing conditions are effective, they are still not sufficient. In addition, from the viewpoint of reducing roll-off from the polishing composition used in the polishing step, use of a specific organic acid typified by an organic acid having a hydroxyl group (Japanese Patent Laid-Open No. 2002-12857), solation of an aluminum salt Although the use of products (Japanese Patent Laid-Open No. 2002-20732) has been studied, it cannot be said that roll-off can be sufficiently reduced.
[0003]
[Problems to be solved by the invention]
As described above, the roll-off in which the end surface portion of the substrate is polished more than the inside is thought to be caused by the pressure at the time of polishing the substrate being higher in the end surface portion than in the inside. . Therefore, the inventors of the present invention greatly polished the end face portion when the abrasive enters between the substrate and a polishing apparatus such as a polishing pad because the difference in pressure is due to the large cohesive force of the abrasive grains. Therefore, the present invention has been completed by paying attention to a compound that controls agglomeration of abrasive grains of an abrasive material, from a new point of view unconventional.
[0004]
Therefore, the present invention provides a roll-off reducing agent capable of sufficiently obtaining a polishing rate and reducing roll-off of a substrate to be polished caused by polishing, a polishing liquid composition containing the roll-off reducing agent, and the polishing liquid It aims at providing the manufacturing method of the board | substrate using a composition, the method of reducing roll-off with this roll-off reducing agent or the said polishing liquid composition.
[0005]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows.
[1]A polishing liquid composition comprising a roll-off reducing agent, an abrasive, an organic acid or a salt thereof, and water, wherein the roll-off reducing agent isInorganic compound having properties for controlling surface potential of abrasive in polishing compositionBecauseAbrasive (A1 composed of α-type corundum crystals₂0₃When a reference polishing composition comprising 20 parts by weight of high-purity alumina having a purity of 98.0% by weight or more), 1 part by weight of citric acid, 78 parts by weight of water and 1 part by weight of an inorganic compound was prepared, the inorganic compound The surface potential of the abrasive in the reference polishing composition is controlled to -110 to 250 mV.A polishing liquid composition, wherein the abrasive comprises α-alumina particles and intermediate alumina particles.,
[2]The inorganic compound is a nitrogen-containing inorganic acid or a salt thereof, a sulfur-containing inorganic acid or a salt thereof, a phosphorus-containing inorganic acid or a salt thereof, a halogen-containing inorganic acid or a salt thereof, a carbonate, a cyanate, and a metal-containing inorganic acid or a salt thereof 1 type or more chosen from the group which consists of a salt of the said [1] descriptionPolishing liquid composition,
[3]The polishing composition according to [1] or [2], wherein the inorganic compound is sulfuric acid or a sulfate.,
[4]Organic acids are (A) citric acid and (B) succinic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, tricarbaric acid, diglycolic acid, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid The polishing composition according to any one of [1] to [3], comprising at least one acid selected from the group consisting of
[5]Using the polishing composition according to any one of [1] to [4], a method for producing a substrate comprising a step of polishing a substrate to be polished, and
[6]  In the polishing processAny one of [1] to [4]Method for reducing substrate roll-off using the polishing composition
About.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the roll-off reducing agent of the present invention is composed of an inorganic compound having the characteristic of controlling the surface potential of the abrasive in the polishing composition, and is composed of an abrasive (α-type corundum crystal). A1203 purity 98.0% by weight or more) When preparing a reference polishing composition comprising 20 parts by weight, citric acid 1 part by weight, water 78 parts by weight and inorganic compound 1 part by weight, Due to the presence of the inorganic compound, the surface potential (hereinafter also referred to as a specific surface potential) of the abrasive in the reference polishing composition is controlled to -110 to 250 mV. In the present invention, by incorporating such a roll-off reducing agent into the polishing composition, the roll-off of the substrate can be significantly reduced, and a remarkable effect that a substrate capable of recording up to the outer peripheral portion can be produced. The
[0007]
The roll-off reducing agent of the present invention has a roll-off reducing action of the substrate to be polished, in addition to the surface potential control action of the abrasive of the polishing composition as described above. The details of these two mechanisms of action are not clear, but the following can be considered. That is, the roll-off reducing agent of the present invention is controlled so that the surface potential of the abrasive is controlled within the above range and the cohesive force between the abrasives is reduced. As a result, the end face portion to which a high pressure is applied during polishing becomes [end face pressure> abrasive cohesion force], and the agglomeration of the abrasive grains is disrupted to reduce the polishing rate. On the contrary, the inner pressure where the pressure is lower than that of the end face portion is [internal pressure <cohesive force], and reagglomeration of the abrasive grains occurs and the polishing rate is maintained. Therefore, the difference in the polishing rate between the inside and the outside (end face portion) becomes small, and roll-off can be reduced.
[0008]
The roll-off reducing agent of the present invention is an inorganic compound that controls the surface potential of the abrasive in the reference polishing liquid composition to −110 to 250 mV. Examples of such inorganic compounds include compounds that do not contain carbon atoms, carbonates, and Examples thereof include carbon-containing Bronsted acid salts such as cyanate.
[0009]
The roll-off reducing agent of the present invention preferably has a specific surface potential of −110 to 200 mV, more preferably −100 to 200 mV, and most preferably −90 to 180 mV from the viewpoint of reducing roll-off. .
[0010]
In the present invention, the reference polishing composition containing 1% by weight of an inorganic compound is 20 parts by weight of an abrasive (A1203 purity high purity alumina composed of α-type corundum crystals). A polishing composition comprising 1 part by weight of citric acid, 78 parts by weight of water and 1 part by weight of a roll-off reducing agent. Accordingly, in the present invention, the surface potential is the surface potential of the abrasive in the polishing composition containing citric acid.
[0011]
A1203 purity high-purity alumina composed of α-type corundum crystals used as an abrasive in the reference polishing liquid composition is composed of SiO as other components.₂1.2 wt% or less, Fe₂O_ThreeIs 0.2 wt% or less, Na₂O is preferably 0.7% by weight or less, and alumina having a cumulative height of 50% and a particle diameter of 0.6 μm is suitable. Specific examples thereof include “WA #” manufactured by Fujimi Incorporated. 10,000 "(trade name).
[0012]
The specific surface potential is the surface potential of the abrasive in the polishing composition, and the above-mentioned reference polishing composition is filtered under reduced pressure with a 0.45 μm filter, and 0.1 g of the recovered polishing residue is collected in water. Re-dispersed to 70 g, and the potential after 5 to 6 minutes is defined as a specific surface potential using a streaming potential detector.
[0013]
Further, the roll-off reducing agent of the present invention is not particularly limited as long as it is an inorganic compound that controls the specific surface potential of the abrasive in the reference polishing composition to -110 to 250 mV, but the surface potential control surface, In view of handling at the time of use, those that dissolve 0.1 g or more with respect to 100 g of water are preferable, more preferably 0.5 g or more, more preferably 1 g or more, and most preferably 5 g or more.
[0014]
In terms of surface potential control, the inorganic compound is preferably an ion dissociable compound, more preferably a Bronsted acid or a salt thereof. More preferably, any dissociation stage may be used, but a Bronsted acid or a salt thereof having a dissociation stage having a pKa (25 ° C., aqueous solution) of −10 to 10 is preferable. Most preferably, a Bronsted acid having a dissociation stage where pKa is 0 to 7 or a salt thereof is preferable.
[0015]
The roll-off reducing agent used in the present invention is preferably one having a pH of 1 to 13 when 0.1 g is added to 100 g of water from the viewpoint of corrosiveness of the substrate and influence on the human body, more preferably 2 to 2. 10.
[0016]
Specific examples of inorganic compounds used in the roll-off reducing agent used in the present invention include nitric acid, potassium nitrate, nickel nitrate, aluminum nitrate, nitrous acid, nitrogen-containing inorganic acids represented by aluminum nitrite or salts thereof, sulfuric acid, Ammonium sulfate, potassium sulfate, nickel sulfate, aluminum sulfate, aluminum sulfite, sulfur-containing inorganic acid represented by ammonium sulfamate or its salt, phosphoric acid, sodium phosphate, nickel phosphate, potassium phosphite, aluminum pyrophosphate Phosphorus-containing inorganic acid or salt thereof, hydrochloric acid, sodium chloride, sodium perchlorate, sodium hypochlorite, halogen-containing inorganic acid represented by potassium bromide, or salt thereof, represented by sodium carbonate, potassium hydrogen carbonate Representative of carbonate, sodium cyanate, potassium cyanate That cyanate, tungstate, ammonium molybdate, metal-containing atom inorganic acid or a salt thereof typified by sodium titanate.
[0017]
Among these inorganic compounds, when considering the roll-off reduction property, polyvalent inorganic acids or salts thereof are preferable, and nonmetallic inorganic acids or salts thereof are preferable from the viewpoint of economy. Furthermore, in view of the persistence of polishing debris on the substrate to be produced, sulfur-containing inorganic acids or salts thereof are more preferable, and sulfur-containing inorganic acid salts are most preferable in consideration of corrosion and the like. Of the sulfur-containing inorganic acids or salts thereof, sulfuric acid or sulfates are particularly preferred.
[0018]
When the roll-off reducing agent is a salt of an ionic inorganic compound, the cationic species is not particularly limited, and specific examples include salts with metals, ammonium, alkylammonium, organic amines and the like. Specific examples of the metal include metals belonging to the periodic table (long-period type) 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8. Among these metals, a metal belonging to Group 1A, 3B or Group 8 is preferable from the viewpoint of reducing roll-off, and a metal belonging to Group 8 is particularly preferable.
[0019]
Specific examples of alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.
[0020]
Specific examples of the organic amine include dimethylamine, trimethylamine, alkanolamine and the like.
[0021]
Among these cationic species, ammonium and metals belonging to Group 8 are particularly preferable.
[0022]
The roll-off reducing agent of this invention can be mix | blended and used for the polishing liquid containing an abrasive, an organic acid or its salt, and water. The polishing liquid composition thus obtained is particularly referred to as “roll-off reducing agent composition” in the present specification. That is, the roll-off reducing agent composition of the present invention contains at least the roll-off reducing agent, an abrasive, an organic acid or a salt thereof, and water.
[0023]
The content of the roll-off reducing agent for controlling the surface potential of the abrasive in the roll-off reducing agent composition is preferably 0.001% by weight or more in the polishing composition from the viewpoint of roll-off reduction and polishing performance. Moreover, 10 weight% or less is preferable from a viewpoint of an economical viewpoint, the surface quality of to-be-polished material, sedimentation of a polishing litter, and adhesion. More preferably, it is 0.005-8 weight%, More preferably, it is 0.01-5 weight%, Most preferably, it is 0.05-3 weight%. In addition, a roll-off reducing agent can be used individually or in mixture of 2 or more types.
[0024]
As the abrasive used in the present invention, an abrasive generally used for polishing can be used. Examples of the abrasive include metals; metal or metalloid carbides, nitrides, oxides, borides; diamond and the like. The metal or metalloid element is derived from Group 2A, 2B, 3A, 3B, 4A, 4B, 5A, 6A, 7A or Group 8 of the periodic table (long period type). Specific examples of abrasives include α-alumina particles, intermediate alumina particles, alumina sol, silicon carbide particles, diamond particles, magnesium oxide particles, zinc oxide particles, cerium oxide particles, zirconium oxide particles, colloidal silica particles, fumed silica particles, etc. The use of one or more of these is preferable from the viewpoint of improving the polishing rate. Moreover, you may mix and use these 2 or more types according to the necessity of a grinding | polishing characteristic. According to the abrasive application, rough polishing of Ni-P plated aluminum alloy substrate is preferably alumina particles such as α-alumina particles, intermediate alumina particles, and alumina sol, and the combination with α-alumina particles and intermediate alumina particles is speed. It is particularly preferable from the viewpoint of improvement, prevention of surface defects and reduction of surface roughness, and a combination of α-alumina particles and γ-alumina and θ-alumina as intermediate alumina is particularly preferable. The mixing ratio of α-alumina and intermediate alumina (intermediate alumina / α-alumina, weight ratio) is preferably 0.1 to 2, more preferably 0.5 to 1. In addition, it is preferable to use silica particles such as colloidal silica particles and fumed silica particles for finish polishing of the Ni-P plated aluminum alloy substrate. For polishing a glass material, cerium oxide particles and alumina particles are preferably used. For polishing semiconductor wafers and semiconductor elements, cerium oxide particles, alumina particles, and silica particles are preferable.
[0025]
The average particle size of the primary particles of the abrasive is preferably 0.01 to 3 μm, more preferably 0.01 to 0.8 μm, and particularly preferably 0.02 to 0.5 μm from the viewpoint of improving the polishing rate. . Furthermore, when primary particles are aggregated to form secondary particles, the average particle size of the secondary particles is similarly from the viewpoint of improving the polishing rate and reducing the surface roughness of the object to be polished. The thickness is preferably 0.02 to 3 μm, more preferably 0.05 to 1.5 μm, and particularly preferably 0.1 to 1.2 μm. The average particle size of the primary particles of the abrasive is observed with a scanning electron microscope (preferably 3000 to 30000 times) or observed with a transmission electron microscope (preferably 10000 to 300000 times), and image analysis is performed. It can be determined by measuring the diameter. The average particle size of the secondary particles can be measured as a volume average particle size using a laser beam diffraction method.
[0026]
The specific gravity of the abrasive is preferably 2 to 6 and more preferably 2 to 5 from the viewpoints of dispersibility, supply to a polishing apparatus, and recovery and reusability.
The total content of the abrasive is preferably 1 to 40% by weight, more preferably in the roll-off reducing agent composition, from the viewpoint of reducing economy and surface roughness and enabling efficient polishing. It is 2 to 30% by weight, more preferably 3 to 25% by weight.
[0027]
The organic acid or salt thereof used in the present invention is not particularly limited as long as it improves the polishing rate, and examples thereof include mono- or polyvalent carboxylic acids, aminocarboxylic acids, amino acids, and salts thereof. These compounds are roughly classified into a compound group (A) and a compound group (B) based on their characteristics.
[0028]
The compounds belonging to the compound group (A) can also improve the polishing rate independently, but as a remarkable feature, roll-off can be achieved when combined with other speed improvers represented by the compound group (B). It is a compound having a reducing action. By combining these compound groups (A) and the roll-off reducing agent that suppresses the surface potential in the present invention, the roll-off can be further reduced. The compounds of the compound group (A) include mono- or polyvalent carboxylic acids having 2 to 20 carbon atoms, dicarboxylic acids having 2 to 3 carbon atoms, monocarboxylic acids having 1 to 20 carbon atoms, and OH groups or SH groups. It is 1 or more types of compounds chosen from these salts. Carbon number of mono- or polyvalent carboxylic acid containing OH group or SH group is 2 to 20 from the viewpoint of solubility in water, preferably 2 to 10, more preferably 2 to 8, still more preferably 2 to 2. 6. For example, from the viewpoint of reducing roll-off, α-hydroxycarboxyl compounds are preferable. C2-C3 dicarboxylic acid means oxalic acid and malonic acid. The number of carbon atoms of the monocarboxylic acid is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 5, from the viewpoint of solubility in water. Of the compound group (A), α-hydroxycarboxylic acid or a salt thereof is preferable from the viewpoint of polishing rate.
[0029]
Specific examples of mono- or polyvalent carboxylic acids having 2 to 20 carbon atoms, dicarboxylic acids having 2 to 3 carbon atoms, and monocarboxylic acids having 1 to 20 carbon atoms containing an OH group or an SH group include JP-A-2002-12857. No. 2 page, right column, line 44 to page 3, left column, line 45, and the like.
[0030]
Specific examples of the carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group include glycolic acid, mercaptosuccinic acid, thioglycolic acid, lactic acid, β-hydroxypropionic acid, malic acid, tartaric acid, citric acid, and isocitric acid. And allocic acid, gluconic acid, glyoxylic acid, glyceric acid, mandelic acid, tropic acid, benzylic acid, salicylic acid and the like. Specific examples of monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, 2-methylhexanoic acid, octanoic acid, 2-ethylhexanoic acid, nonane Acid, decanoic acid, lauric acid and the like can be mentioned. Among these, acetic acid, oxalic acid, malonic acid, glycolic acid, lactic acid, malic acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid are preferable, and oxalic acid, malonic acid, glycolic acid, lactic acid, apple are more preferable. Acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid, particularly preferably citric acid.
[0031]
There are no particular limitations on the salt of these compound groups (A), and specific examples include salts with metals, ammonium, alkylammonium, organic amines, and the like. Specific examples of the metal include metals belonging to the periodic table (long-period type) 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8. Among these metals, metals belonging to Group 1A, 3A, 3B, 7A or 8 are preferred from the viewpoint of reducing clogging, metals belonging to Group 1A, 3A or 3B are more preferred, and sodium and potassium belonging to Group 1A are the most. preferable.
[0032]
Specific examples of alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.
[0033]
Specific examples of the organic amine include dimethylamine, trimethylamine, alkanolamine and the like.
[0034]
Among these salts, ammonium salt, sodium salt and potassium salt are particularly preferable.
[0035]
A compound group (A) may be used independently and may be used in mixture of 2 or more types.
[0036]
The compound group (B) used in the present invention is a compound that is particularly excellent in the action of improving the polishing rate. Examples of the compound group (B) include polyvalent carboxylic acids, aminocarboxylic acids, amino acids and salts thereof having no OH group or SH group having 4 or more carbon atoms.
From the viewpoint of improving the speed, 4 to 20 carbon atoms are preferable among polyvalent carboxylic acids having no OH group or SH group having 4 or more carbon atoms, and 4 to 10 carbon atoms are preferable from the viewpoint of water solubility. Moreover, the carboxylic acid valence is 2-10, Preferably it is 2-6, Most preferably, it is 2-4. From the same viewpoint, the aminocarboxylic acid preferably has 1 to 6 amino groups and more preferably 1 to 4 amino groups in one molecule. The number of carboxylic acid groups is preferably 1 to 12, and more preferably 2 to 8. Moreover, as carbon number, 1-30 are preferable, Furthermore, 1-20 are preferable. From the same viewpoint, the number of carbon atoms of the amino acid is preferably 2-20, and more preferably 2-10.
[0037]
Specific examples of the compound group (B) include those described in JP-A No. 2002-30276, page 4, left column, line 13 to page 4, line 30.
[0038]
Specifically, succinic acid, maleic acid, fumaric acid, glutaric acid, citraconic acid, itaconic acid, tricarbaric acid, adipic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3, 4-tetracarboxylic acid, diglycolic acid, nitrotriacetic acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetetraacetic acid (HEDTA), triethylenetetraminehexaacetic acid (TTHA), dicarboxymethylglutamic acid (GLDA), glycine, alanine and the like.
Of these, succinic acid, maleic acid, fumaric acid, glutaric acid, citraconic acid, itaconic acid, tricarbaric acid, adipic acid, diglycolic acid, nitrotriacetic acid, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid are preferred, and succinic acid and maleic acid are also preferred. Fumaric acid, citraconic acid, itaconic acid, tricarbaric acid, diglycolic acid, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid are more preferable.
[0039]
Examples of the salt of the compound group (B) include the same compounds as the compound group (A).
[0040]
A compound group (B) may be used independently and may be used in mixture of 2 or more types. Furthermore, it is particularly preferable to combine the compound group (A) and the compound group (B) in terms of the balance of polishing performance.
[0041]
Further, the total content of the organic acid or a salt thereof is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% in the roll-off reducing agent composition, from the viewpoint of developing the function and from the viewpoint of economy. % By weight, more preferably 0.03 to 5% by weight.
[0042]
Water in the roll-off reducing agent composition of the present invention is used as a medium, and the content thereof is preferably 55 to 98.999% by weight, more preferably from the viewpoint of efficiently polishing an object to be polished. Is 60 to 97.5% by weight, more preferably 70 to 96.8% by weight.
[0043]
The roll-off reducing agent composition of the present invention may contain other components as necessary. Examples of other components include an oxidizing agent, a rust inhibitor, and a basic substance. Specific examples of the oxidizing agent are disclosed in JP-A-63-251163, page 2, lower left column, lines 7 to 14, JP-A-3-115383, page 2, lower right column, lines 16 to page 3, upper left column, line 11, No. 4-275387, page 2, right column, line 27 to page 3, left column, line 12 and the like. These components may be used alone or in combination of two or more. Further, the content is preferably 0.05 to 20% by weight, more preferably 0.05 to 10% by weight, more preferably 0.05 to 10% by weight in the roll-off reducing agent composition, from the viewpoints of developing the respective functions and economical efficiency. Preferably it is 0.05-5 weight%.
[0044]
Furthermore, a disinfectant, an antibacterial agent, etc. can be mix | blended as another component as needed. The content of these bactericides and antibacterial agents is 0.0001 to 0.1% by weight, more preferably 0.001 to 0.05% by weight in the roll-off reducing agent composition from the viewpoints of developing functions, influence on polishing performance, and economic aspects. More preferably, it is 0.002 to 0.02% by weight.
[0045]
In addition, although the density | concentration of each component in the said roll-off reducing agent composition is a density | concentration preferable at the time of grinding | polishing, it may be the density | concentration at the time of manufacture of this composition. Usually, the polishing composition is produced as a concentrated solution, which is often used after being diluted.
Further, the roll-off reducing agent composition can be produced by adding and mixing desired additives by any method.
[0046]
The pH of the roll-off reducing agent composition is preferably determined as appropriate according to the type of the object to be polished and the required quality. For example, the pH of the roll-off reducing agent composition is preferably 2 to 12 from the viewpoints of the washability of the object to be polished, the corrosion resistance of the processing machine, and the safety of the operator. In addition, when the object to be polished is a substrate for precision parts mainly made of metal such as an aluminum alloy substrate plated with Ni-P, the pH is increased from the viewpoint of improving the polishing rate, improving the surface quality, and preventing pad clogging. 2-10 are preferable, 2-9 are more preferable, 2-7 are more preferable, Most preferably, it is 2-5. Furthermore, polishing of semiconductor wafers and semiconductor elements, especially silicon substrates, polysilicon films, SiO₂When used for polishing a film or the like, 7 to 12 is preferable, 8 to 11 is more preferable, and 9 to 11 is particularly preferable from the viewpoint of improving the polishing rate and improving the surface quality. If necessary, the pH may be adjusted with inorganic acids such as nitric acid and sulfuric acid, oxycarboxylic acids, polyvalent carboxylic acids, aminopolycarboxylic acids, organic acids such as amino acids, and metal salts and ammonium salts thereof, ammonia, sodium hydroxide, water It can adjust by mix | blending basic substances, such as a potassium oxide and an amine, with a desired quantity suitably.
[0047]
The manufacturing method of the board | substrate of this invention has the process of grind | polishing a to-be-polished board | substrate using the said roll-off reducing agent composition.
The material of the object to be polished typified by the substrate to be polished, which is the subject of the present invention, is, for example, a metal or semi-metal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, and these metals as a main component. And glassy materials such as glass, glassy carbon, and amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium nitride, resins such as polyimide resin, and the like. Among these, metals such as aluminum, nickel, tungsten and copper and alloys based on these metals are objects to be polished, or semiconductor substrates such as semiconductor elements containing these metals are objects to be polished. It is preferable that In particular, it is preferable to use the roll-off reducing agent composition of the present invention when polishing a substrate made of an aluminum alloy plated with Ni—P because roll-off can be particularly reduced. Accordingly, the present invention relates to a method for reducing the roll-off of the substrate.
[0048]
The shape of these objects to be polished is not particularly limited. For example, a shape having a flat portion such as a disk shape, a plate shape, a slab shape, or a prism shape, or a shape having a curved surface portion such as a lens can be used for the roll-off of the present invention. It becomes the object of polishing using the reducing agent composition. Among these, it is particularly excellent for polishing a disk-shaped workpiece.
[0049]
The roll-off reducing agent composition of the present invention is suitably used for polishing precision component substrates. For example, it is suitable for polishing a substrate of a magnetic recording medium such as a magnetic disk, an optical disk, and a magneto-optical disk, a photomask substrate, glass for liquid crystal, an optical lens, an optical mirror, an optical prism, and a semiconductor substrate. Polishing of a semiconductor substrate includes polishing performed in a silicon wafer (bare wafer) polishing process, a buried element isolation film forming process, an interlayer insulating film flattening process, a buried metal wiring forming process, a buried capacitor forming process, and the like. The roll-off reducing composition of the present invention is particularly suitable for polishing a magnetic disk substrate.
[0050]
Further, in the method for reducing the roll-off of the substrate to be polished using the roll-off reducing agent of the present invention, the above-mentioned substrate to be polished is a polishing liquid containing the roll-off reducing agent of the present invention or the roll-off reducing agent composition of the present invention. By polishing the product itself as a polishing liquid, roll-off of the substrate to be polished can be significantly reduced. For example, the substrate is sandwiched by a polishing disk with a non-woven organic polymer polishing cloth or the like attached thereto, and the polishing liquid containing the roll-off reducing agent of the present invention or the roll-off reducing agent composition of the present invention is applied to the polishing surface. A substrate with reduced roll-off can be manufactured by supplying and moving the polishing board and the substrate while applying pressure.
[0051]
In the present invention, the roll-off generated on the substrate to be polished is measured, for example, by measuring the shape of the end surface portion using a stylus type or optical shape measuring device, and the end surface portion is compared with the center of the disk from the profile. It is possible to evaluate by quantifying how much is cut.
[0052]
As shown in FIG. 1, the quantification method takes three points on a measurement curve (meaning the shape of the end surface portion of the substrate to be polished) such as points A, B, and C, which are separated from the center of the disk by a certain distance. , The straight line connecting points A and C is used as the base line, and the distance (D) between point B and the base line is said. Good roll-off means that the D value is closer to zero. The roll-off value is a value obtained by dividing D by 1/2 of the amount of change in disk thickness before and after polishing.
[0053]
The roll-off reducing agent composition of the present invention is particularly effective in the polishing process, but can be similarly applied to other polishing processes such as a lapping process.
[0054]
【Example】
Examples 1-6, Comparative Example 1
(Surface potential measurement)
1. Method for blending polishing liquid composition for surface potential measurement
20 parts by weight of an abrasive (product name: WA # 10000, manufactured by Fujimi Incorporated) was added to a solution obtained by dissolving 1 part by weight of citric acid in 59 parts by weight of ion-exchanged water and stirred for about 30 minutes to polish. 80 parts by weight of the liquid composition (a) was obtained.
[0055]
The reference polishing liquid composition containing 1% by weight of the roll-off reducing agent was added with 20 parts by weight of a 5% by weight aqueous solution of the roll-off reducing agent while sufficiently stirring 80 parts by weight of the polishing liquid composition (a) for 30 minutes. The mixture was stirred to a certain extent. In addition, the reference polishing liquid composition not containing a roll-off reducing agent to be compared was obtained by adding 20 parts by weight of ion-exchanged water and stirring for about 30 minutes while sufficiently stirring 80 parts by weight of the polishing liquid composition (a). It was.
[0056]
2. Surface potential measurement method
About 20 g of the reference polishing composition (Examples 1 to 6) or the reference polishing composition containing no roll-off reducing agent (Comparative Example 1) is filtered under reduced pressure with a 0.45 μm hydrophilic PFTE filter for 5 hours, and the remaining filtration The abrasive material that was the inspection was collected. The collected abrasive was transferred to a 20 mL beaker and ground with a 5 mm diameter glass rod until particles of about 1 mm were lost. In a 100 mL beaker, 0.1 g of this abrasive and 70 g of water were thoroughly evaluated and a 25 mm stir bar was placed. PIST is set to a scale of 550 and agitation of 500 using a flow potential detector (potential difference automatic titrator manufactured by Kyoto Electronics Co., Ltd., product name: AT-410, streaming potential detection unit, product name: PCD-500). Then, measurement of the surface potential was started, and the potential after 5 minutes was defined as the specific surface potential. These results are shown in Table 1.
[0057]
[Table 1]

[0058]
From the results shown in Table 1, in each of the reference polishing liquid compositions of Examples 1 to 6 containing the roll-off reducing agent of the present invention, the specific surface potential is controlled to -110 to 250 mV with respect to -123 mV of the comparative example. You can see that
[0059]
Examples 7 to 15 and Comparative Examples 2 to 4
[Polishing polishing composition composition method]
16 parts by weight of α-alumina (purity about 99.9%) with an average primary particle size of 0.23 μm and an average secondary particle size of 0.65 μm, θ-alumina (average particle size 0.22 μm, specific surface area 150 m)²/ g, purity of about 99.9%), 4 parts by weight, as other additives, roll-off reducing agents listed in Tables 2-3, a predetermined amount of compound group (A) or compound group (B), ion-exchanged water (remainder) And 100 parts by weight of the polishing composition were obtained.
[0060]
Polishing method
The resulting polishing composition was diluted 3 times (vol / vol) with ion-exchanged water, and a tally step manufactured by Rank Taylor Hobson (stylus tip size: 25 μm × 25 μm, high-pass filter: 80 μm, measurement length: The surface of the substrate made of Ni-P plated aluminum alloy with a center line average roughness Ra of 0.2 μm, a thickness of 1.27 mm and a diameter of 3.5 inches (diameter 95.0 mm) measured by a double-sided machine Polishing was performed under the setting conditions of the two-sided processing machine to obtain a polished product of a Ni-P plated aluminum alloy substrate used as a substrate for a magnetic recording medium.
The setting conditions of the double-sided machine are shown below.
[0061]
<Setting conditions of double-sided machine>
Double-sided machine: 9B type double-sided machine manufactured by Speed Farm Co., Ltd.
Processing pressure: 9.8kPa
Polishing pad: Fujibow Co., Ltd., H9900 (trade name)
Plate rotation speed: 30rpm
Polishing liquid composition dilution flow rate: 125ml / min
Polishing time: 3.5min
Number of substrates loaded: 10
[0062]
[Polishing speed]
Weigh each substrate before and after polishing (measured by Sartorius, product name: BP-210S), determine the weight change of each substrate, determine the average value of 10 substrates as the reduction amount, and use it as the polishing time. The value obtained by dividing by was used as the weight reduction rate. The weight reduction rate was introduced into the following equation and converted to a polishing rate (μm / min). In Examples 7 to 13, the polishing rate of Comparative Example 2 was used, and in Examples 14 and 15 and Comparative Example 4, the polishing rate of Comparative Example 3 was used as the reference value 1, and the relative values of the polishing rates of the respective experimental examples (relative speeds). )

[0063]
[Roll off]
Measurement was performed under the following conditions using Maxim 3D5700 (trade name) manufactured by Zygo.
Lens: Fizeau × 10
Analysis software: Zygo Metro Pro (trade name)
Using the above device, measure the shape of the end of the disk from 41.5 mm to 47.0 mm from the center of the disk. As shown in FIG. 1, the positions of points A, B and C are 41.5 mm, 47 mm and For 43 mm, D (difference in position between the baseline and point B) was determined by the measurement method using analysis software. A value obtained by dividing the obtained D by 1/2 of the disk polishing amount before and after polishing was defined as a roll-off value.
[0064]
Table 2 shows the relative speed and the relative roll-off value when the measured value of Comparative Example 2 is the reference value 1, and Table 3 shows the measured value of Comparative Example 3 is the reference value 1.
[0065]
[Table 2]

[0066]
[Table 3]

[0067]
From the results of Tables 2 and 3, by adding the roll-off reducing agent of the present invention to the polishing composition (Examples 7 to 15), compared with the case where no roll-off reducing agent is added (Comparative Examples 2 to 4). It can be seen that roll-off can be reduced without reducing the polishing rate.
Further, from the comparison between Comparative Example 3 and Example 14, even when several kinds of organic acids are mixed, the roll without reducing the polishing rate can be obtained by adding the roll-off reducing agent that suppresses the surface potential of the present invention. It can be seen that off can be reduced.
[0068]
【The invention's effect】
By using the roll-off reducing agent of the present invention and the roll-off reducing agent composition containing the roll-off reducing agent for polishing a substrate for precision parts, the effect of significantly reducing the roll-off of the substrate is exhibited.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a relationship between a measurement curve and roll-off.

Claims (6)

A polishing liquid composition comprising a roll-off reducing agent, an abrasive, an organic acid or a salt thereof, and water, wherein the roll-off reducing agent has a surface potential of the abrasive in the polishing liquid composition. an inorganic compound having a control characteristic, (A1 ₂ 0 ₃ purity 98.0% or more by weight of high-purity alumina, which is composed of α-type corundum crystal) 20 parts by weight of the abrasive, 1 part by weight of citric acid, water When a reference polishing composition comprising 78 parts by weight and 1 part by weight of an inorganic compound was prepared, the surface potential of the abrasive in the reference polishing composition was controlled to -110 to 250 mV due to the presence of the inorganic compound. A polishing composition, wherein the abrasive comprises α-alumina particles and intermediate alumina particles. The inorganic compound is a nitrogen-containing inorganic acid or a salt thereof, a sulfur-containing inorganic acid or a salt thereof, a phosphorus-containing inorganic acid or a salt thereof, a halogen-containing inorganic acid or a salt thereof, a carbonate, a cyanate, and a metal-containing inorganic acid or a salt thereof The polishing composition according to claim 1, wherein the polishing composition is one or more selected from the group consisting of salts . The polishing composition according to claim 1 or 2, wherein the inorganic compound is sulfuric acid or a sulfate . Organic acids are (A) citric acid and (B) succinic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, tricarbaric acid, diglycolic acid, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid The polishing liquid composition in any one of Claims 1-3 containing the 1 or more acid chosen from the group which consists of . The manufacturing method of the board | substrate which has the process of grind | polishing a to-be-polished board | substrate using the polishing liquid composition in any one of Claims 1-4 . The method to reduce the roll-off of a board | substrate using the polishing liquid composition in any one of Claims 1-4 in a grinding | polishing process.

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