JP3875156B2 - Roll-off reducing agent - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roll-off reducing agent and a polishing liquid composition using the same. Furthermore, it is related with the manufacturing method of a board | substrate using this polishing liquid composition, and the method of reducing the roll-off of a board | substrate.
[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. Further, from the viewpoint of reducing roll-off by the polishing composition used in the polishing process, the 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 The use of products (Japanese Patent Laid-Open No. 2002-20732), the use of polyalkylene oxide compounds (Japanese Patent Laid-Open No. 2002-167575) and the like have been studied, but it cannot be said that roll-off can be sufficiently reduced. Is the current situation.
[0003]
[Problems to be solved by the invention]
The present invention uses a roll-off reducing agent capable of sufficiently obtaining a polishing rate and reducing roll-off of a substrate caused by polishing, a polishing liquid composition containing the roll-off reducing agent, and the polishing liquid composition. Another object of the present invention is to provide a method for reducing roll-off using a substrate manufacturing method, the roll-off reducing agent or the polishing composition.
[0004]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows.
[1]A polishing composition comprising a roll-off reducing agent, an abrasive and water,
The roll-off reducing agent isIt is composed of Bronsted acid or a salt thereof having a viscosity decreasing action of 0.01 mPa · s or more as shown in the following formula.The
Viscosity reduction amount = viscosity of reference polishing composition-viscosity of roll-off reducing agent-containing polishing composition
[However, the reference polishing liquid composition is an abrasive (Al composed of α-type corundum crystals.₂O₃The composition comprises 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 and 79 parts by weight of water. The roll-off reducing agent-containing polishing composition is composed of an abrasive (α type corundum crystals). Al₂O₃High-purity alumina having a purity of 98.0% by weight or more) 20 parts by weight, 1 part by weight of citric acid, 78.9 parts by weight of water, and 0.1 part by weight of a roll-off reducing agent.^-1, Meaning viscosity at 25 ° C. ],And
Formula 1 to Formula 3:
[Chemical Formula 3]
(Where M ¹ And M ² Represents hydrogen atom, metal atom, ammonium, or organic ammonium, regardless of whether they are the same or different)
A compound containing one or more functional groups shown in
Or Equation 4:
[Formula 4]
(Where M ¹ And M ² Is the same as above. M ³ Represents a hydrogen atom, a metal atom, ammonium, or organic ammonium)
A compound represented by
Polishing liquid composition in which the abrasive comprises α-alumina particles and intermediate alumina particles.,
[2]Furthermore, an organic acid or a salt thereof is contained.[1] descriptionThe laboratoryPolishing liquid composition,
[3]The organic acid is citric acidThe polishing composition according to [2] aboveobject,
[4]in front[1]~ [3] eitherDescribedPolishing liquid compositionUsing,Manufacturing a substrate having a step of polishing a substrate to be polishedMethod and
[5] saidAny one of [1] to [3]Method for reducing substrate roll-off by polishing using the described polishing liquid composition
About.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the roll-off reducing agent of the present invention is a roll-off reducing agent composed of Bronsted acid or a salt thereof having a viscosity decreasing action of 0.01 mPa · s or more represented by the following formula.
Viscosity reduction amount = viscosity of reference polishing composition-viscosity of roll-off reducing agent-containing polishing composition
[However, the reference polishing composition is composed of 20 parts by weight of abrasive (high purity alumina composed of α-type corundum crystals of Al2O3 purity of 98.0% by weight or more), 1 part by weight of citric acid and 79 parts by weight of water. The roll-off reducing agent-containing polishing composition is 20 parts by weight of abrasive (high purity alumina composed of α-type corundum crystals and having an Al 2 O 3 purity of 98.0% by weight or more), 1 part by weight of citric acid, and 78.9 water. Part and 0.1 part by weight of a roll-off reducing agent, viscosity is 1500 S shear rate.^-1, Meaning a viscosity at 25 ° C. (hereinafter also referred to as a specific viscosity). ]
[0006]
In the present invention, by adding such a roll-off reducing agent to the polishing composition, the roll-off of the substrate can be significantly reduced, and a substrate having a large storage capacity that can be recorded up to the outer peripheral portion can be produced. The effect is expressed.
[0007]
In the roll-off reducing agent of the present invention, the shear rate 1500 S of the roll-off reducing agent-containing polishing composition^-1As the amount of decrease in viscosity (specific viscosity) at 25 ° C., as will be described later, the supply amount of the polishing liquid composition between the pad and the substrate to be polished and the removal of polishing debris are improved, and a sufficient roll-off reducing action is achieved. From the viewpoint of obtaining the above, 0.01 mPa · s or more, preferably 0.02 mPa · s or more, more preferably 0.03 mPa · s or more, particularly preferably 0.1 mPa · s or more, and a sufficient polishing rate. From the viewpoint of obtaining, it is preferably 1 mPa · s or less, more preferably 0.9 mPa · s or less. Considering both the roll-off reducing effect and the polishing rate, the amount of decrease in the specific viscosity is preferably 0.02 to 1 mPa · s, more preferably 0.03 to 1 mPa · s, and particularly preferably 0.1 to 0. .9 mPa · s.
[0008]
The reference polishing liquid composition used in the present invention is 20 parts by weight of an abrasive (high purity alumina composed of α-type corundum crystals and having an Al 2 O 3 purity of 98.0% by weight or more), 1 part by weight of citric acid and water 79. It is a polishing composition composed of parts by weight. Further, the roll-off reducing agent-containing polishing composition is 20 parts by weight of abrasive (high purity alumina composed of α-type corundum crystals and having a purity of 98.0% by weight or more), 1 part by weight of citric acid, water This polishing composition is composed of 78.9 parts by weight and 0.1 part by weight of a roll-off reducing agent. And the amount of viscosity reduction in the present invention refers to the amount of decrease in the viscosity of the roll-off reducing agent-containing polishing liquid composition with the reference polishing composition as a comparison target. Can be calculated.
Viscosity reduction amount = viscosity of reference polishing composition-viscosity of roll-off reducing agent-containing polishing composition
[0009]
As high purity alumina composed of α-type corundum crystals used as an abrasive when measuring the amount of reduced viscosity, Al2O3 purity of 98.0% by weight or more, other components include SiO.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).
[0010]
The viscosity is a shear rate of 1500S of the polishing composition.^-1The viscosity at 25 ° C. is measured with an instrument capable of measuring the high shear viscosity of the polishing composition, and specifically, Ares-100FRT-BATH- manufactured by Reometric Scientific under the conditions described in the examples below. A value measured using STD (trade name).
[0011]
As described above, the roll-off reducing agent of the present invention has an effect of reducing the roll-off of the substrate to be polished in addition to the effect of reducing the specific viscosity of the polishing composition. The relationship between these two mechanisms of action is not clear in detail, but the following can be considered. In other words, the roll-off reducing agent acts as a so-called rheology control agent on the interface of the dispersoid, controls mainly the size and number of collisions between the dispersoid particles, and destroys the structure formed by other compounds. The specific viscosity is reduced. In addition, the specific viscosity of the polishing composition is reduced in this way, so that the ability of supplying the polishing composition to the pad and the substrate to be polished and the discharge of polishing debris are improved. It is estimated that the polishing amount on the inner side (substrate center) of the substrate increases and the difference in polishing rate between the inner side and the outer side (end surface portion) of the substrate becomes relatively small, and as a result, the roll-off is reduced.
[0012]
The roll-off reducing agent used in the present invention is a Bronsted acid or salt thereof that reduces the specific viscosity by 0.01 mPa · s or more. Here, the Bronsted acid is an aqueous solution that converts water molecules to H.⁺Is a compound that gives an oxonium ion. Moreover, there is no limitation in particular as the salt, For example, the salt with organic ammonium, such as a metal or ammonium or alkylammonium, an organic amine, is mentioned.
[0013]
Examples of the roll-off reducing agent include Formula 1 to Formula 3:
[0014]
[Chemical Formula 3]
[0015]
(Where M¹And M²Are hydrogen atom, metal atom, ammonium, or organic ammonium, regardless of whether they are the same or different)
Or a compound containing one or more functional groups represented by formula (4):
[0016]
[Formula 4]
[0017]
(Where M¹And M²Is the same as above, M^ThreeRepresents a hydrogen atom, a metal atom, ammonium, or organic ammonium)
The compound shown by these is preferable.
[0018]
From the viewpoint of specific viscosity reduction and handling, the molecular weight of the roll-off reducing agent containing the functional group represented by Formula 1 to Formula 3 in the molecule is preferably 100 to 10,000, more preferably 100 to 5000, Preferably it is 150-2000.
[0019]
The number of functional groups represented by the formulas 1 to 3 per molecule of the roll-off reducing agent is preferably 1 to 100, more preferably 1 to 50, and particularly preferably 1 to 20 in terms of specific viscosity reduction and handling. is there.
[0020]
Among the compounds having one or more functional groups represented by Formula 1 to Formula 3 and the compounds represented by Formula 4, when the amount of viscosity reduction is taken into consideration, the compound having the functional group represented by Formula 1, 2, or 3 is A compound having a functional group represented by Formula 2 or 3 is particularly preferable.
[0021]
Among them, in consideration of industrial availability, the compound containing the functional group represented by Formula 1 is represented by Formula 5:
[0022]
[Chemical formula 5]
[0023]
[In the formula, R¹Represents a hydrocarbon group having 1 to 24 carbon atoms. M¹And M²Is the same as above. ]
The compound shown by is more preferable. In this case, R¹One or more hydrogen atoms therein may be substituted with a hydroxyl group, an amino group, or a functional group represented by Formula 1. Moreover, as a compound containing the functional group shown by Formula 2, Formula 6, 7:
[0024]
[Chemical 6]
[0025]
[In the formula, R²Is a hydrocarbon group having 1 to 24 carbon atoms which may have another functional group, R^ThreeIs an alkylene oxide group having 2 to 4 carbon atoms or
[0026]
[Chemical 7]
[0027]
, R^FourRepresents a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom. n represents a positive integer of 1 to 100. M¹, M²And M^ThreeIs the same as above. ]
The compound shown by these is preferable. Where R², R^FourOne or more hydrogen atoms in the hydrocarbon group may be substituted with a functional group such as a hydroxyl group or an amino group. Furthermore, as a compound containing the functional group represented by Formula 3, Formula 8:
[0028]
[Chemical 8]
[0029]
[R^Five, R⁶Represents a hydrocarbon group having 1 to 24 carbon atoms. M¹Is the same as above. ]
The compound shown by these is preferable. Where R^Five, R⁶One or more hydrogen atoms in the hydrocarbon group may be substituted with a functional group such as a hydroxyl group or an amino group.
[0030]
M in the formula¹~ M^ThreeWhen is not a hydrogen atom, 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, From the viewpoint of reducing roll-off, a metal belonging to Group 1A, 3A, 3B, 7A or 8 is preferred, a metal belonging to Group 1A, 3A or 3B is more preferred, and sodium and potassium belonging to Group 1A are most preferred. Specific examples of alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like. Specific examples of the organic amine include dimethylamine, trimethylamine, alkanolamine and the like. Of these, ammonium, sodium and potassium are particularly preferred.
[0031]
Specific examples of the compound containing the functional group of formulas 1 to 3 and the compound represented by formula 4 include linear or cyclic inorganic phosphoric acids, organic phosphonic acids or salts thereof, phosphoric acid monoesters, phosphoric acid diesters. And salts thereof. Examples of linear or cyclic inorganic phosphoric acids include phosphoric acid, polyphosphoric acid, metaphosphoric acid, and pyrophosphoric acid. Examples of organic phosphonic acids include aminotri (methylene phosphonic acid) “Diquest 2000 (manufactured by Solcia Japan)”, 1- Hydroxyethylidene-1, 1-diphosphonic acid “Diquest 2010 (manufactured by Solcia Japan)”, tricarboxylbutanephosphonic acid “Diquest 7000 (manufactured by Solcia Japan)” and the like are monoesters of lauryl phosphate. Esters, stearyl phosphate monoester salts, polyoxyethylene monolauryl ether phosphate monoesters, polyoxyethylene monomyristyl ether phosphate monoesters, etc., and phosphoric diesters include dilauryl phosphate diester, bis (polyoxyethylene monoester) Lauryl ether) There are exemplified, respectively. Among these, in terms of industrial availability, economy, and handling, inorganic phosphoric acids are preferable, and inorganic condensed phosphoric acids obtained by condensing two or more inorganic phosphoric acids are particularly preferable.
[0032]
The roll-off reducing agent of the present invention can be used by blending it with a polishing composition containing an abrasive, water and the like. 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 and water.
[0033]
The content of the roll-off reducing agent in the roll-off reducing agent composition is preferably 0.001% by weight or more in the polishing composition from the viewpoint of viscosity reduction (roll-off reduction) and polishing performance. From the economical viewpoint and the viewpoint of the surface quality of the object to be polished, it is preferably 5% by weight or less. More preferably, it is 0.005 to 3 weight%, More preferably, it is 0.01 to 1.5 weight%, Most preferably, it is 0.05 to 1 weight%. In addition, a roll-off reducing agent can be used individually or in mixture of 2 or more types.
[0034]
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 grinding | polishing characteristic. PolishingMaterialFor the purpose of rough polishing of an aluminum alloy substrate plated with Ni-P, alumina particles such as α-alumina particles, intermediate alumina particles, and alumina sol are preferable, and α-alumina particles and intermediate alumina particles (especially θ-alumina). Is particularly preferable from the viewpoint of improving the polishing rate, preventing surface defects and reducing the surface roughness. In addition, the finish polishing of the Ni-P plated aluminum alloy substrate is preferably performed using silica particles such as colloidal silica particles and fumed silica particles. For polishing a glass material, cerium oxide particles and alumina particles are preferred. For polishing semiconductor wafers and semiconductor elements, cerium oxide particles, alumina particles, and silica particles are preferable.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
Moreover, other components can be mix | blended with the roll-off reducing agent composition of this invention according to the objective. The other compound is preferably an organic acid or a salt thereof as a polishing rate improver.
[0039]
The organic acid or a salt thereof 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.
[0040]
The compounds belonging to the compound group (A) can improve the polishing rate independently, but as a remarkable feature, roll off when combined with other polishing rate improvers represented by the compound group (B). It is a compound which also has the effect | action which reduces this. By combining these compound groups (A) and the roll-off reducing agent of 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.
[0041]
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.
[0042]
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 preferred are malic acid, tartaric acid and citric acid, and most preferred is citric acid.
[0043]
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.
[0044]
Specific examples of alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.
[0045]
Specific examples of the organic amine include dimethylamine, trimethylamine, alkanolamine and the like.
[0046]
Among these salts, ammonium salt, sodium salt and potassium salt are particularly preferable.
[0047]
A compound group (A) may be used independently and may be used in mixture of 2 or more types.
[0048]
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 polishing rate, among polyvalent carboxylic acids having no OH group or SH group having 4 or more carbon atoms, 4 to 20 carbon atoms are preferable, 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 as described above, the number of carbon atoms of the amino acid is preferably 2 to 20, and more preferably 2 to 10.
[0049]
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.
[0050]
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.
[0051]
Examples of the salt of the compound group (B) include the same compounds as the compound group (A).
[0052]
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.
[0053]
In addition, the total content of these organic acids or salts thereof is preferably 0.01 to 10% by weight, more preferably 0.02 in the roll-off reducing agent composition, from the viewpoint of developing the function and from the viewpoint of economy. -7% by weight, more preferably 0.03-5% by weight.
[0054]
Moreover, as other components other than the said organic acid or its salt, an inorganic acid and its salt, an oxidizing agent, a rust preventive agent, a basic substance, etc. are mentioned. Specific examples of inorganic acids and salts thereof and oxidizing agents are disclosed in JP-A-62-25187, page 2, upper right column, lines 3 to 11, and JP-A-63-251163, page 2, lower left column, lines 7 to 14. JP-A-1-205973, page 3, upper left column, line 11 to upper-right column, line 2, JP-A-3-115383, page 2, lower-right column, line 16 to page 3, upper-left column, line 11, JP-A-4-275387 Examples include those described in page right column, line 27 to page 3, left column, line 12 and the like. Specific examples of inorganic acids and salts thereof include sulfur-containing inorganic acids and salts thereof typified by sulfuric acid, ammonium sulfate, potassium sulfate, nickel sulfate, aluminum sulfate, aluminum sulfite, and ammonium sulfamate. 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%.
[0055]
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.
[0056]
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.
In addition, the roll-off reducing agent composition can be produced by adding and mixing desired additives by any method.
[0057]
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.
[0058]
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.
[0059]
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.
[0060]
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.
[0061]
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.
[0062]
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.
[0063]
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.
[0064]
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.
[0065]
【Example】
Examples 1 to 5 and Comparative Examples 1 and 2
(Viscosity measurement)
1. Method of blending polishing liquid composition for viscosity measurement
Dissolve and stir 1 part by weight of citric acid in 69 parts by weight of ion-exchanged water, and then add 20 parts by weight of a polishing material (product name: WA # 10000, manufactured by Fujimi Incorporated) with stirring. 90 parts by weight of the composition (a) was obtained.
[0066]
The reference polishing liquid composition was prepared by adding 10 parts by weight of ion-exchanged water and stirring for 30 minutes while sufficiently stirring 90 parts by weight of the polishing liquid composition (a).
[0067]
The roll-off reducing agent-containing polishing liquid composition was prepared by adding 10 parts by weight of a 1% aqueous solution of the target roll-off reducing agent while sufficiently stirring 90 parts by weight of the polishing liquid composition (a) and stirring for 30 minutes. did.
[0068]
2. Viscosity measurement method
The viscosities of the reference polishing composition and the roll-off reducing agent-containing polishing composition were measured under the following conditions.
Measuring instrument: Reometric Scientific, Ares-100FRT-BATH-STD (trade name)
Measuring jig: ARES-COU32T34A (trade name)
Measurement conditions: Test type Rete Sweep
Temperature 25 ℃
Initial shear rate 1S^-1
Final shear rate 1500S^-1
point per Decade 5
Measurement Time 2
Analysis software: Orchestrator Software ver.6.4.3 (Product name)
The obtained results are shown in Table 1.
[0069]
[Table 1]
[0070]
From the results shown in Table 1, it can be seen that all of the roll-off reducing agents used in Examples 1 to 5 have an effect of reducing the viscosity of the polishing composition. Moreover, it turns out that the compound of the comparative example 1 does not reduce the viscosity of polishing liquid composition. Further, the compound of Comparative Example 2 has a viscosity reduction amount of 0.01 mPa · s or more, but is not Bronsted acid or a salt thereof. As can be seen from the results of Comparative Example 5 in Table 2 described later, It can be seen that the roll-off reducing effect is inferior to the roll-off reducing agent of the invention.
[0071]
Examples 6-15, Comparative Examples 3-9
[Polishing method for polishing composition]
Abrasive 20 parts by weight (average primary particle diameter 0.23 μm, secondary particle average 0.65 μm α-alumina (purity about 99.9%) 16 parts by weight, intermediate alumina (θ alumina, average particle diameter 0.22 μm) , Purity of about 99.9%) 4 parts by weight), and other additives as shown in Tables 2 to 5 are mixed and stirred with a predetermined amount of ion-exchanged water (remainder), and 100 parts by weight of the polishing composition is mixed. Obtained.
[0072]
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 Polishing was performed under the following setting conditions of the double-sided processing machine, and a polished article of an Ni-P plated aluminum alloy substrate used as a substrate for a magnetic recording medium was obtained.
The setting conditions of the double-sided machine are shown below.
[0073]
<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
[0074]
[Polishing speed]
Weigh each substrate before and after polishing and measure it using [BP-210S (trade name), manufactured by Sartorius Co., Ltd.] to determine the weight change of each substrate, and use the average value of 10 sheets as the amount of reduction, and polish it The value divided by time was defined as the weight reduction rate. The weight reduction rate was introduced into the following equation and converted to a polishing rate (μm / min).
[0075]
[0076]
[Roll off]
Measurement was performed under the following conditions using Maxim 3D5700 (trade name) manufactured by Zygo.
Lens: Fizeau × 1
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.
[0077]
[Table 2]
[0078]
Table 2 shows relative values when the polishing rate and the roll-off value of Comparative Example 3 are set to the reference value 1, respectively. From the results of Table 2, it can be seen that in Examples 6 to 10 using the roll-off reducing agent having a specific viscosity lowered in Table 1, the roll-off is reduced while maintaining the polishing rate substantially as compared with Comparative Example 3. Moreover, it turns out that the roll-off value does not reduce in Comparative Example 4 using sodium nitrate in which no decrease in viscosity was observed in Table 1. It can be seen that in Comparative Example 5 using a polypropylene oxide polyethylene oxide block polymer, the amount of roll-off reduction is small.
[0079]
[Table 3]
[0080]
Table 3 shows relative values when the polishing rate and the roll-off value of Comparative Example 6 are each set to the reference value 1. From the results in Table 3, it can be seen that in Example 11 using the roll-off reducing agent having a specific viscosity lowered in Table 1, the roll-off is reduced while maintaining the polishing rate substantially as compared with Comparative Example 6.
[0081]
[Table 4]
[0082]
Table 4 shows relative values when the polishing rate and the roll-off value of Comparative Example 7 are each set to the reference value 1. From the results of Table 4, it can be seen that there is a roll-off reduction effect by using the roll-off reducing agent of the present invention even when a plurality of auxiliary agents are present.
[0083]
[Table 5]
[0084]
Table 5 shows relative values when the polishing rate and roll-off value of Comparative Example 9 are set to the reference value 1. From the results in Table 5, it can be seen that there is a roll-off reduction effect by using the roll-off reducing agent of the present invention even when a plurality of auxiliary agents are present.
[0085]
【The invention's effect】
By using the roll-off reducing agent or the roll-off reducing agent composition containing the roll-off reducing agent of the present invention for polishing a precision component substrate or the like, 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 (5)

A polishing liquid composition comprising a roll-off reducing agent, an abrasive and water, wherein the roll-off reducing agent has a viscosity reducing action with a viscosity reduction amount of 0.01 mPa · s or more represented by the following formula: Ri Do from Bronsted acid or a salt thereof,
Viscosity reduction amount = viscosity of reference polishing liquid composition−viscosity of polishing liquid composition containing roll-off reducing agent [However, the reference polishing liquid composition is an abrasive (Al ₂ O ₃ purity 98 composed of α-type corundum crystals) 0.0 wt% or more of high-purity alumina) 20 parts by weight, citric acid 1 part by weight and water 79 parts by weight, and the roll-off reducing agent-containing polishing composition is an abrasive (Al composed of α-type corundum crystals). ₂ O ₃ purity 98.0 wt% or more high-purity alumina) 20 parts by weight, citric acid 1 part by weight, water 78.9 parts by weight and roll-off reducing agent 0.1 part by weight, the viscosity is shear rate 1500 S ^{− 1} means viscosity at 25 ° C. ], And
Formula 1 to Formula 3:
(In the formula, M ¹ and M ² are each the same kind or different kinds, each representing a hydrogen atom, a metal atom, ammonium, or organic ammonium)
A compound containing one or more functional groups shown in
Or Equation 4:
( Wherein , M ¹ and M ² are the same as described above. M ³ represents a hydrogen atom, a metal atom, ammonium, or organic ammonium)
A compound represented by
A polishing liquid composition, wherein the abrasive comprises α-alumina particles and intermediate alumina particles. Further, the polishing liquid composition of claim 1, wherein comprising the organic acid or a salt thereof. The polishing composition according to claim 2, wherein the organic acid is citric acid. 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 1-3 . The method to reduce the roll-off of a board | substrate by grind | polishing using the polishing liquid composition in any one of Claims 1-3 .