JP2001031954A - Separated abrasive grain slurry composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separated abrasive grain slurry composition which can uniformly polish a composite material comprising a mixture of materials different in hardness without causing selective polishing by incorporating abrasive grains, a dispersion medium, an alcoholic-OH-containing compound, and optionally a dispersant into the same. SOLUTION: Preferably, the alcoholic-OH-containing compound is a prim. to tert. alcohol of the formula: R1-OH, a polyoxyalkylene monoether compound of the formula: P2O-(CnH2nO)mH or a polyoxyalkylene monoester compound of the formula: R3COO-(CnH2nO)mH. In the formulas, R1 is 4-18C alkyl, alkenyl, alkynyl, alkaryl, or aryl; R2 is 1-18C alkyl, alkenyl, alkynyl, alkaryl, or aryl; R3 is 1-18C alkyl; n is 2-4; and m is 1-4. The composition is suitable for processing a composite material comprising a plurality of materials different in hardness without causing the difference in the amount of polishing between soft materials and hard materials otherwise caused by lapping and polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for producing a composite material composed of a plurality of different hardness materials having different hardnesses. The present invention relates to a free abrasive slurry composition suitable for use in a step of uniformly processing.

[0002]

2. Description of the Related Art In recent years, optical parts, electronic parts, precision mechanical parts, and the like have been increasingly required to have higher performance and higher functions. Materials used are metal crystal materials, ceramics, glass, and plastics. And it is very diverse. As one of the manufacturing processes of such components, polishing of a composite material composed of a plurality of materials having different hardnesses has been increasing. Examples of polishing of composite materials include texturing of Ni-P plating layers on hard disk substrates for electronic components, uniform processing of wiring metal and interlayer insulating films in the multilayer wiring process of LSI, and zirconia called ferrule for optical components. Polishing of an end face of an optical fiber connector which is a composite material of a system ceramic and a quartz glass called a core of a fiber portion and a fluororesin called a glad.

The recording density of a hard disk drive, which is a recording medium of a computer, is being improved year by year. As one of means for achieving a high recording density, an attempt has been made to reduce the spacing between the hard disk and the magnetic head and reduce the spacing between the disk and the head, that is, to lower the flying height of the head. The magnetic head mounted on the hard disk drive is mainly a thin film magnetic head, and is inductive, and has an MR (Magn) as a recording / reproducing element.
et Resistance: MR-inductive hybrid type using a magnetoresistive element, and further GMR (Gia
nt MR (giant magnetoresistive element). These thin-film magnetic heads are made of AlTiC (Al ₂ O ₃
-TiC) a base material such as alumina (Al ₂ O ₃₎ protection, such as / insulating film made ceramics and permalloy (Fe
-Ni), a composite material of a metal film or the like which is a magnetic material such as sendust (Fe-Al-Si).

[0004] An ABS (Air Bearing Surf) of a thin film type magnetic head is manufactured using a conventional loose abrasive slurry.
When performing ace: ABS (air floating surface) polishing, a metal film such as permalloy or sendust which is a soft material is selectively processed due to a difference in hardness between materials, and a step and a surface roughness are generated. Things were mostly. Therefore, the metal film such as the magnetic pole portion is retreated from the ABS made of ceramics, and the pole tip recession (PoleTip) which increases the magnetic distance from the recording medium is increased.
(Recession: PTR), which causes a substantial increase in the flying height of the head.

Therefore, in order to avoid such selective polishing and damage, it is necessary to add a selective polishing inhibitor to the free abrasive slurry to achieve a highly accurate polished surface.
0-113327 and JP-A-10-255022. JP-A-10-113327 discloses that a propylene oxide having a molecular weight of 300 to 20,000 and optionally a polyether having a functional group of a hydroxyl group of 1 to 6 obtained by an addition reaction of ethylene oxide are added to a free abrasive slurry as a selective polishing inhibitor. By,
An attempt is made to avoid selective polishing caused by lapping of the ABS of the thin-film magnetic head and to improve the polished surface condition.

In Japanese Patent Application Laid-Open No. Hei 10-255022, a sulfur-containing organic molybdenum compound is used as a selective polishing inhibitor. Molybdenum disulfide (MoS ₂ ), which is decomposed by frictional heat generated during polishing and forms a film without reacting with the metal surface, and the layers are bonded by van der Waals' force with weak intermolecular force A layered structure mainly composed of a molybdenum disulfide, and the friction at the contact surface is replaced by the friction between the layers inside the molybdenum disulfide. Is effectively prevented.

Various free abrasive slurry compositions using compounds having an alcoholic hydroxyl group have been devised in various ways. The conventional free abrasive slurry composition to which alcohol is added is mainly a system using an aqueous dispersion medium.
In 261386, a lubricant is used as a polyhydric alcohol, an alkyl ether of a polyhydric alcohol, an allyl ether of a polyhydric alcohol, and an aqueous solution thereof for the purpose of preventing a decrease in lapping / polishing performance due to a composition change due to evaporation of a lubricant component during use. A slurry-type slurry-type lapping / polishing lubricant obtained by mixing and dispersing abrasive grains in a substrate selected from the group consisting of:
In Japanese Patent Application Laid-Open No. 9-256171, surface processing on a Ni-based plated substrate, that is, workability of plane polishing processing or texture processing, dispersibility of abrasive grains in a processing liquid in which abrasive grains are dispersed, during or after processing Water-soluble oil composition for processing that simultaneously satisfies the non-adhesiveness of the chips on the underlying film (cleanability after processing) and the good error characteristics after the formation of the magnetic film, and the processing including the composition Fluid has been reported. Further, Japanese Patent Application Laid-Open Nos. 8-41443 and 10-20441
9, JP-A-10-249713 and the like, polyoxyalkylene monoalkyl ethers, polyoxyalkylene monoalkyl phenyl ethers and polyoxyalkylene mono fatty acids which are compounds having an alcoholic hydroxyl group as an abrasive dispersant in a free abrasive slurry composition Nonionic surfactants such as esters are used. However, these are not intended to prevent selective polishing of a soft material generated during polishing of a material of different hardness according to the present invention and to improve the polishing rate.

However, in the conventional free-abrasive slurry composition, the selective polishing prevention mainly acts on the metal film, and only the selective polishing is prevented. However, it is increasingly required to lower the flying height of the head. The PTR value must be further reduced to prevent selective polishing of the metal film, and at the same time, in the polishing process using free abrasive slurry, a shoulder generated at the boundary between the base material Altic and the insulating film alumina. There is a problem that a step called a step must be reduced. Further, considering the processing ability of the free abrasive grain slurry, there is a problem that if the lubricating property is excessively increased, the frictional property is also reduced, so that the polishing rate of the free abrasive grain slurry is reduced.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a free grinding method suitable for uniform processing without causing a difference in the amount of polishing between different kinds of materials, that is, selective polishing, particularly when polishing a thin film magnetic head. Provided is a free-abrasive slurry composition for obtaining a high polished surface quality while maintaining a high polishing rate.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a free abrasive slurry composition for polishing a composite material in which different hardness materials are mixed, comprising a polishing material particle, a dispersion medium and at least one alcoholic hydroxyl group. A free abrasive slurry composition comprising a compound having the compound and optionally a dispersant. In addition, the present invention provides the compound having an alcoholic hydroxyl group represented by the structural formula (I):

[0011]

Embedded image embedded image R ¹ —OH (I) (where R ¹ represents an alkyl group, an alkenyl group, an alkynyl group, an alkylaryl group or an aryl group having 4 to 18 carbon atoms) The free abrasive slurry composition described above, wherein the compound having an alcoholic hydroxyl group has a structural formula (II)

[0012]

Embedded image R ² O— (C _n H _{2n + 1} O) _m H (II) (R ² is an alkyl group having 1 to 18 carbon atoms, an alkenyl group, an alkynyl group, an alkylaryl group or an aryl group, n Represents 2 to 4, m represents 1 to 4.) The free abrasive slurry composition described above, which is a polyoxyalkylene monoether compound represented by the formula (III):

[0013]

Embedded image R ³ COO— (C _n H _{2n + 1} O) _m H (III) (R ³ is an alkyl group having 1 to 18 carbon atoms, n is 2 to 4,
m represents 1-4. The above-mentioned free abrasive slurry composition, which is a polyoxyalkylene monoester compound represented by the formula (1), comprising a step of polishing a surface serving as an air bearing surface of the thin-film magnetic head. In a manufacturing method, the polishing is a method of polishing a thin-film magnetic head using any of these free abrasive slurry compositions. By using such a free abrasive slurry composition, it is characterized in that selective polishing of a metal film which occurs when polishing a thin film type magnetic head and occurrence of a shoulder difference between Altic / Alumina are prevented.

When a compound having an alcoholic hydroxyl group is used as the selective polishing inhibitor of the present invention, the alcoholic hydroxyl group, which is a polar group present in the molecule, is selectively adsorbed on the metal surface. It is thought to be lower. On the other hand, there is no significant difference in the adsorption amount of the compound having an alcoholic hydroxyl group with respect to alumina, which is a base material having a low interaction with the compound having an alcoholic hydroxyl group as compared with the metal, alumina which is an insulating film and a protective film. It is considered to be excellent in the ability to prevent selective polishing between Altic / Alumina. Further, since the alcoholic hydroxyl group is relatively weakly adsorbed on the solid surface as compared with the carboxyl group, it is expected that polishing can be performed while maintaining a high polishing rate. Therefore, in order to eliminate the difference in the amount of polishing between different hardnesses generated when performing the polishing process of the composite material and to uniformly polish, and to maintain the polishing efficiency of the free abrasive slurry, that is, the polishing rate, It is an effective means to add at least one compound having an alcoholic hydroxyl group to the abrasive slurry composition.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a free abrasive polishing slurry composition comprising a compound having an alcoholic hydroxyl group as a selective polishing inhibitor, a dispersion medium and abrasive particles, and optionally a dispersant such as a surfactant. In order to overcome the problem of selective polishing between an AlTiC / alumina / metal film that occurs when polishing a thin-film magnetic head that requires a low PTR value and achieve a low PTR value, the present inventors Are
As a result of intensive studies, the use of a free abrasive slurry composition containing at least one or more compounds having an alcoholic hydroxyl group as a selective polishing inhibitor prevents selective polishing caused by lapping, and is still high. It has been found that a low PTR value can be achieved while maintaining the polishing rate.

The compounds having an alcoholic hydroxyl group used in the present invention include alcohols, polyoxyalkylene monoether compounds and polyoxyalkylene monoester compounds.

The alcohol used in the present invention has the following formula

Embedded image R ¹ —OH (I) (R ¹ is an alkyl group or an alkenyl group having 4 to 18, preferably 10 to 18, more preferably 10 to 14 carbon atoms;
Represents an alkynyl group, an alkylaryl group or an aryl group, preferably an alkyl group. ) Is a primary to tertiary alcohol, preferably a primary alcohol. Examples of these are 1-
Butanol, isobutanol, 2-butanol, ter
t-butanol, 1-buten-3-ol, 3-buten-1-ol, 2-buten-1-ol, 1-butyne-
3-ol, 2-butyn-1-ol, 3-butyn-1
-Ol, 1-pentanol, 2-pentanol, 3-
Pentanol, tert-amyl alcohol, 3-methyl-1-butanol, 1-penten-3-ol, 2-
Penten-1-ol, 4-penten-1-ol, 2
-Methyl-3-buten-2-ol, 3-methyl-2-
Buten-1-ol, 3-methyl-3-buten-1-ol, 1-pentyn-3-ol, 2-pentyn-1-
All, 3-pentin-1-ol, 4-pentin-1
-Ol, 4-pentyn-2-ol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol,
2-methyl-2-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol,
3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2,2-dimethyl-1-butanol, 2-ethylbutanol, 1-hexen-3-ol, 2-hexen-1-ol , 3-hexen-1-ol, 4-hexen-1-ol, 5-hexen-1-
All, 2,4-hexadien-1-ol, 1-hexyn-3-ol, 2-hexyn-1-ol, 3-hexyn-1-ol, 5-hexyn-1-ol, 5-hexyn-1-ol
Hexin-3-ol, 3-methyl-1-pentin-3
-Ol, 1-heptanol, 2-heptanol, 3-
Heptanol, 4-heptanol, 3-ethyl-3-pentanol, 2-methyl-2-hexanol, 2-hepten-1-ol, 4-hepten-1-ol, 1-heptin-3-ol, 2-heptin -1-ol, 3-
Heptin-1-ol, 4-heptin-2-ol, 5
-Heptin-3-ol, 5-methyl-1-hexyne-
3-ol, 1-octanol, 2-octanol, 3
-Octanol, 4-octanol, 2-methyl-2-
Heptanol, 3-methyl-3-heptanol, 4-methyl-4-heptanol, 5-methyl-1-heptanol, 5-methyl-2-heptanol, 5-methyl-3-
Heptanol, 6-methyl-2-heptanol, 6-methyl-3-heptanol, 2,2-dimethyl-3-hexanol, 2,3-dimethyl-2-hexanol, 2,
5-dimethyl-2-hexanol, 2,5-dimethyl-
3-hexanol, 3,4-dimethyl-3-hexanol, 3,5-dimethyl-3-hexanol, 2-ethyl-1-hexanol, 3-ethyl-2-methyl-3-pentanol, 1-decanol, -Dodecanol, 1-
Examples thereof include tetradecanol, 1-hexadecanol, 1-octadecanol and the like, with 1-decanol, 1-dodecanol and 1-tetradecanol being preferred.

The polyoxyalkylene monoether compound used in the present invention is represented by the following formula:

Embedded image R ² O— (C _n H _{2n + 1} O) _m H (II) (R ² is an alkyl group or alkenyl having 1 to 18, preferably 1 to 10, more preferably 1 to 4 carbon atoms. A group, an alkynyl group, an alkylaryl group or an aryl group, preferably an alkyl group, n represents 2 to 4, preferably 2 to 3, more preferably 2, and m represents 1 to 4, preferably 1 or 2.) expressed. Examples of these are 2-methoxyethanol, 2-ethoxyethanol, 2-n-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-isobutoxyethanol,
(Hexyloxy) ethanol, 2- (dodecyloxy) ethanol, 2- (allyloxy) ethanol, 2
Phenoxyethanol, 2- (benzyloxy) ethanol, 2- (2-methoxyethoxy) ethanol, 2
-(2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-isobutoxyethoxy) ethanol, 2- (2-tert-butoxyethoxy) ethanol, 2- [2- (hexyloxy) )
Ethoxy] ethanol, 2- [2- (dodecyloxy)
Ethoxy] ethanol, 2- [2- (tetradecyloxy) ethoxy] ethanol, 2- [2- (hexadecyloxy) ethoxy] ethanol, 2- [2- (octadecyloxy) ethoxy] ethanol, 2- [2- (2-
Methoxyethoxy) ethoxy] ethanol, 2- [2-
(2-ethoxyethoxy) ethoxy] ethanol, 2-
[2- (2-butoxyethoxy) ethoxy] ethanol, 2- [2- [2- (dodecyloxy) ethoxy] ethoxy] ethanol, 2- [2- [2- (2- (tetradecyloxy) ethoxy] ethoxy] ethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, 2- (2-methoxypropoxy)
Propanol, 2- [2- (octylphenyloxy)
Ethoxy] ethanol, 2- [2- (nonylphenyloxy) ethoxy] ethanol, 2- [2- (dinonylphenyloxy) ethoxy] ethanol, and the like are preferred, with 2-ethoxyethanol being particularly preferred.

The polyoxyalkylene monoester compound used in the present invention is represented by the following formula:

Embedded image R ³ COO— (C _n H _{2n + 1} O) _m H (III) (R ³ is an alkyl group having 1 to 18, preferably 1 to 10, more preferably 1 to ³ carbon atoms, n Is 2 to 4, preferably 2 to 3, more preferably 2, and m represents 1 to 4, preferably 1 to 2.) Examples of these are 2-
Hydroxyethyl acetate, 2-hydroxyethyl caprylate, 2-hydroxyethyl caprynate, 2-
Examples include hydroxyethyl laurate, 2-hydroxyethyl palmitate, 2-hydroxyethyl oleate, polyethylene glycol monooleate 2EO, and the like.

The free abrasive slurry composition to which the compound having an alcoholic hydroxyl group is added alone or in an optional ratio of two or more prevents selective polishing of a soft material generated by polishing of a material having a different hardness, and furthermore, It is possible to reduce the processing step between metal and ceramics uniformly without lowering the polishing efficiency (polishing speed). These compounds having an alcoholic hydroxyl group used in the present invention have a boiling point of 80 ° C. or higher, preferably a boiling point of 10 ° C.
0 ° C. or higher. This is because the selective polishing inhibitor having a high evaporation rate evaporates during the polishing operation and makes stable polishing difficult. The concentration of the selective polishing inhibitor used in the present invention is 0.5 wt% or more, preferably 1.0 wt% or more, more preferably 1.0 to 50 wt%, based on the free abrasive slurry composition. is there.

The dispersion medium used in the present invention is made of a non-aqueous solvent as the dispersion medium since metal films such as permalloy and sendust, which are constituent materials of the thin-film magnetic head, are generally weak against water and generate corrosion and rust. It is desirable to use a non-polar solvent having a low polarity. Here, the polarity of the dispersion medium is a property based on the dipole generated in the molecule depending on the kind of atoms in the solvent molecule and its bond, the atomic group and the arrangement of the atoms and the position thereof in a commonly used sense. The magnitude of this polarity is relatively determined by the polarity of the interacting molecules. The polarity of the solvent is qualitatively represented by the Hildebrand solubility parameter (sp value) δ value. The greater the δ value, the greater the polarity, and the smaller the δ value, the smaller the polarity. This δ value can be further divided by some molecular interactions such as dispersion, orientation by polarity, and hydrogen bonding, and these values are used to determine the solubility of a compound in a compound such as what kind of compound the solvent dissolves well. Determines gender. The organic solvent suitable for the dispersion medium of the free abrasive slurry slurry of the present invention preferably has a low δ value. This is because the odor of the dispersion medium becomes a problem due to the increase of the polar component, and the dispersion medium itself has a bad influence on the human body and the object to be polished.

Further, in the present invention, a solvent having a low evaporation rate of the dispersion medium is suitable for eliminating the evaporation of the polishing slurry during the polishing process and performing a stable polishing process. This is because the dispersion medium with a high evaporation rate evaporates during the polishing operation,
This is because stable polishing becomes difficult. From these, the dispersion medium used in the present invention has a boiling point of 100 ° C. or higher,
More preferably, it is 120 ° C. or more, and the solubility parameter sp value is 10.0 or less, preferably 8.0 or less, and the relative speed is 5.0 or less, more preferably 2.0 or less. Examples of these dispersion media include odorless isoparaffinic solvents: Isopar series and low odor naphthenic solvents: EXXXSOL series manufactured by Exxon Chemical Co., Ltd.
Mobil Chemical's n-paraffinic solvents: White Rex series and industrial aliphatic solvents such as Pegasol, Pegawhite, Sartrex and the like.

The dispersant includes a surfactant, a polymer compound and a surface modifier, and these may be used in combination.
In order to produce a stable dispersion from the state of powder, the wettability at the solid / liquid interface must be good. Here, the wettability
A phenomenon in which a liquid displaces a gas from a solid surface. Since air is strongly adsorbed on the surface of a dried powder, it is necessary to replace the air with a liquid. Further, in order to improve the wettability, the chemical affinity between solid and liquid may be increased, and the affinity increases as the polarity and chemical structure of the two become closer. General abrasive particles exhibit hydrophilic properties due to the presence of polar functional groups such as hydroxyl groups on their surface, and can be easily dispersed in polar solvents with high δ values such as water because of their good wettability. It is. However, since the dispersion medium used in the present invention is a non-polar solvent, it is necessary to increase the affinity between the particle surface and the dispersion medium in order to uniformly disperse the abrasive particles, which are hydrophilic particles, in the non-polar solvent. Instead, it is necessary to perform a hydrophobic treatment on the particle surface. As a method of the hydrophobic treatment, there is a method of adding a dispersant such as a surfactant.

The method of using a surfactant as a dispersant is as follows.
Utilizing that a surfactant is an amphiphilic substance having a long hydrophobic hydrocarbon chain in a molecule and a strong polar group (= hydrophilic group) at a terminal. Specifically, the interaction between the hydrophilic particle surface and the polar group of the surfactant causes the hydrophobic hydrocarbon chains to be adsorbed outward, so that the overall surface properties of the particles are hydrophilic. From hydrophobic to hydrophobic, and can be stably present in non-polar solvents without sedimentation.

The surfactant as a dispersant used in the present invention must be soluble in a non-polar solvent, and such a surfactant has a double bond or triple bond in its molecular skeleton. In general, there is a branch or a branch. Such surfactants include, for example, sorbitan monooleate, sorbitan sesquioleate, and sorbitan trioleate, which are sorbitan fatty acid esters, and decaglyceryl pentaoleate, decaglyceryl pentaisostearate, and triolein, which are glycerin esters. Acid decaglyceryl, hexaglyceryl pentaoleate, glyceryl monoisostearate,
Polyoxyethylene sorbite fatty acid esters such as diglyceryl monoisostearate, polyoxyethylene sorbite tetraoleate, polyethylene glycol fatty acid esters, polyethylene glycol monooleate 2EO, 6EO, and POE, polyoxyethylene alkyl ether based 2) Oleyl ether, POE (3) secondary alkyl ether and the like. The concentration of the surfactant used in the present invention may be not less than the concentration at which the particles cause saturated adsorption, and varies depending on the surface properties of the abrasive particles used and the type of the surfactant. This is because, in a non-polar solvent, the amount of adsorption of the surfactant in the first layer is smaller than that in the aqueous system, so that it is difficult for the surfactants to perform two-layer adsorption using hydrophobic-hydrophobic interaction. This is because the surface properties do not change with the addition concentration of the surfactant.

Further, a surface modifier such as a polymer compound or a silane coupling agent may be used as the dispersant. The polymer compound is adsorbed on the particle surface to form a thick adsorption layer. Utilizing that the thick adsorption layer prevents the particles from approaching each other sterically. In the method using a surface modifier, a method is used in which the surface functional group on the particle surface is bonded to the surface modifier by a chemical reaction to change the surface property of the particle from hydrophilic to hydrophobic. The method is not limited to the method described above, and the hydrophobic abrasive particles can be uniformly dispersed in the non-polar solvent by performing the hydrophobic treatment. The content of the dispersant in the free abrasive slurry composition is 0.01% by weight or more, preferably 0.05 to
5.0% by weight.

The abrasive particles can be used without any particular limitation as long as they are generally used for polishing. Specific examples include diamond, alumina, silicon carbide, cerium oxide, zirconium oxide, silicon oxide, iron oxide, and the like. Generally, diamond abrasive particles are used for processing a thin-film magnetic head because the base material is Altic and hard, and the general particle size is generally 1.0 μm or less, more preferably 0.5 μm or less. Diamond abrasive particles are used. Also,
The crystal structure of diamond may be polycrystal or single crystal depending on the manufacturing method, and either may be used depending on the purpose of polishing. The concentration of diamond particles added to the free abrasive slurry is generally about 0.05 to 1.0% by weight, which is also adjusted by the polishing efficiency and the polished surface quality.

As the method for producing the free abrasive slurry composition of the present invention, a general method for producing a free abrasive slurry can be applied. That is, an appropriate amount of abrasive particles is mixed with a dispersion medium in which an appropriate amount of a surfactant or the like can be dissolved. In this state, since the surface of the abrasive particles is hydrophilic, they exist in an agglomerated state in the nonpolar solvent. Therefore, dispersion is performed to make the aggregated abrasive particles primary particles. In the dispersing step, a general dispersing method and dispersing apparatus can be used. Specifically, for example, an ultrasonic dispersing machine, various bead mill dispersing machines, a kneader, a ball mill and the like can be applied. By using a dispersing device, particles are dispersed to primary particles, a surfactant is adsorbed on the surface where the particles appear, and by improving the wettability, it becomes possible to prepare a slurry having good dispersion stability without agglomeration. .

The object to be polished according to the present invention is mainly composed of a soft material having a Vickers hardness (Hv) of 26 to 360 and a Hv of 700 to 4
It is a composite material in which 000 different hardness materials are mixed. The soft material and the hard material included here may be one kind or plural kinds, respectively. This soft material is in particular a metal, for example Ti
(Hv: 60), Pb (Hv: 37), Ag (Hv: 2)
6), W (Hv: 360), V (Hv: 55), Nb
(Hv: 80), Ta (Hv: 355), Pd (Hv:
38), Cr (Hv: 130), Ru (Hv: 35)
0), Cu (Hv: 117), Pt (Hv: 39), M
o (Hv: 160), Th (Hv: 38), Ni (Hv
v: 60), sendust (Fe-Al-Si, Hv: 6)
00), permalloy (Fe-Ni, Hv: 200), and aluminum (Hv: 200). The hard material is ceramics, glass, etc., for example, quartz glass (H
v: 620), AlTiC _{(Al 2 O 3 -TiC, Hv} :
2500), TiC (Hv: 3200), AlN (Hv: 1
370), Si ₃ N ₄ (Hv: 2160), ZrO ₂ (Hv: 70
0), cBN (Hv: 4000), SiO ₂ (Hv: 620),
SiC (Hv: 2400), hBN (Hv: 4700), AlT
iC (Hv: 2500), Al ₂ O ₃ (Hv: 2000), Si ₃
N ₄ (Hv: 2160), AlN (Hv: 1370), MgO
(Hv: 920), B ₄ C (Hv: 3200), TaN (Hv:
1080). In particular, when the object to be polished is a thin film type magnetic head, the object to be polished has a structure in which different hardness materials such as Altic, Sendust, Permalloy, and alumina are mixed as shown in FIG.

The method of measuring Hv is specified in JIS Z2251. Specifically, using a diamond square quadrangular pyramid indenter having a diagonal angle of 136 °, it is calculated from the test load when a test piece is provided with a depression and the surface area obtained from the diagonal length of the depression using the following equation.

HV = 0.102 (F / S) = 0.102 · (2Fsinθ / 2) /d2=0.18909F/d2 where HV is the Vickers hardness, F is the test load (N), S is the surface area of the depression, D Average diagonal length of the hollow (mm),
θ represents the facing angle of the diamond indenter. The tester for Vickers hardness is JIS B7725, and the reference piece for hardness is steel (JIS G4401, JIS G4805) and brass (JIS H31
00) and copper (JIS H3100). In addition, the surface roughness of the range of use of the reference piece is a mirror surface of 0.1 s according to JIS B0601 (surface roughness), and the parallelism of the front and back surfaces of the reference piece is according to JIS B0621 (definition and display of accuracy of shape and position), It is specified to be 0.02mm or less per 50mm.

Examples of polishing using the free abrasive slurry composition of the present invention include optical fiber connectors,
Any kind of composite material having different hardness and surface properties, such as a semiconductor element, a VTR head, and a floppy head, can be applied to anything, and an example of application to the processing of a thin-film magnetic head will be described below as an example. Levitation type magnetic heads are generally manufactured in the following steps: Bar cutting This bar is obtained by cutting a wafer in which a large number of magnetic exchange elements are formed in a matrix as shown in FIG.
A plurality of sliders are arranged in a row. 2. 2. Adhere the bar to the processing jig (see Fig. 3) Bar lapping process (see FIG. 4) The lapping process is as shown in FIG. 4, in which a platen mainly made of tin or the like is rotated, and a polished object is placed on the platen to supply free abrasive slurry or the like. While doing, slider ABS
The polishing process. 4. 4. Remove the bar from the processing jig. Rail etching step 6. Bar separated into sliders

[0032] In this step, the present invention provides: It relates to polishing in lapping processing of bars. Slider ABS
Is generally performed using a free abrasive slurry while controlling the throat height and the MR height. Here, the throat height (TH) is one of the factors that determine the recording / writing characteristics of the thin-film magnetic head. The throat height is obtained by removing a thin-film coil from ABS as shown by TH in FIG. It is the distance of the magnetic pole portion to the end of the insulating layer that is electrically separated. A thin-film type magnetic head having a magnetoresistive reproducing element is referred to as an MR-inductive composite head. As one factor for determining the recording / reproducing characteristics in this MR-inductive composite head, a high magnetic resistance reproducing element is used. This is called MR height (MR-h). The MR height is a distance measured from the ABS of the magnetoresistive reproducing element whose end face is exposed to the ABS as indicated by MR-h in FIG.

[0033]

EXAMPLE 1 In this example, the effect of selective polishing prevention when polishing a thin-film magnetic head composed of Altic, Sendust and Permalloy was examined. Also, a slurry using oleic acid and stearic acid, which are known as polishing aids, and a slurry with no additive were compared. The compositions of the free abrasive slurries used in the examples and comparative examples are shown in Tables.
Shown in 1.

[0034]

[Table 1]

Isopar M, a nonpolar solvent, is used as a dispersion medium, and sorbitan monooleate, a nonionic surfactant, is used as a surfactant (Nikko Chemicals Co., Ltd.)
Made. Trade name: SP-O10) was used. For the polishing experiment, an automatic precision lapping machine HY manufactured by Nippon Engis Co., Ltd.
PREZEJ-3801N type was used. The polishing conditions were as follows: tin / lead platen on lapping machine, platen rotation speed 60 rpm, slurry slurry supply rate sprayed at 30 second intervals for 3 seconds, processing load 13
00 g / cm 2 and the processing time were 30 minutes. The polishing characteristics were evaluated by using a scanning probe microscope (AFM) to determine the step generated between the AlTiC and the metal film of the thin-film magnetic head after polishing, that is, the pole tip recession value (PTR value). Here, the PTR value of the thin film magnetic head is 3
nm or less was regarded as good. The AFM and the differential interference optical microscope were used for the evaluation of the scratch and the surface roughness. The polishing rate was measured from the weight change of the object to be polished before polishing and after polishing for 30 minutes under the above-mentioned polishing conditions. Table 2 shows the results.

[0036]

[Table 2]

Here, the polishing rate is a relative value of each polishing rate when the amount of polishing of the thin film type magnetic head by the free abrasive slurry composition containing no additive is 100.
From these experimental results, the PTR values of the thin-film magnetic heads polished using the free abrasive slurry containing the compound having an alcoholic hydroxyl group were lower than those of the comparative examples in which oleic acid, stearic acid and no additive were used. Lower,
The thin film magnetic head composed of composite materials having different hardnesses could be polished more uniformly. In addition, fatty acids (oleic acid,
A remarkable decrease in the polishing rate is observed in the slurry to which (stearic acid) is added, but the polishing rate is improved in the free abrasive slurry to which the compound having an alcoholic hydroxyl group is added as compared with the case where no compound is added. confirmed. The polished surface was equivalent or better than oleic acid, stearic acid and no additive. Further, 1-decanol and 1-tetradecanol were particularly good on the polished surface. In addition, the PTR values of the thin-film magnetic heads polished using a free abrasive slurry containing one or more compounds having an alcoholic hydroxyl group are lower than those of the comparative examples in which oleic acid, stearic acid and no additive are used. As a result, the thin film magnetic head composed of composite materials having different hardnesses could be polished more uniformly. The polished surface was equivalent or better than oleic acid, stearic acid and no additive.

Example 2 In this example, the PTR value, the polished surface and the relative polishing rate when the addition amount of the compound having an alcoholic hydroxyl group was changed from 0 to 50 wt% were evaluated. The conditions were the same as in Example 1 except that the compound having an alcoholic hydroxyl group was 1-decanol. Table 3 shows the results.

[0039]

[Table 3]

From the experimental results of this example, it was found that the PTR value was reduced at 0.5 wt% or more, and the effect of preventing the selective polishing of the thin film type magnetic head as a composite material was exhibited. The polished surface condition was better than the comparative example. 1.0 wt% or more, more preferably 1.
In the range of 0 to 30.0% by weight, scratches and surface roughness were the least and particularly good. From the results of these examples, by polishing using a free abrasive slurry containing a single compound or two or more compounds having an alcoholic hydroxyl group, a composite material having a different hardness is generated by a difference in hardness between the materials. Uniform polishing processing that prevented selective polishing became possible.

Although the present invention has been described with reference to an example in which the present invention is applied to polishing of a thin-film magnetic head, the present invention is not limited to this, and can be applied to polishing of other composite materials having different hardnesses.
The point is that the compound having an alcoholic hydroxyl group selectively acts on the material surface without causing a difference in the amount of polishing between different materials, and is applicable when a uniform polishing process and a high polishing rate are required. I can do it.

[Brief description of the drawings]

FIG. 1 is a cross-sectional structure of a thin-film magnetic head to be polished.

FIG. 2 shows the structure of a thin-film magnetic head.

FIG. 3 is a perspective view showing sticking of the cut bar to a processing jig.

FIG. 4 is a perspective view showing an example of a bar wrapping process.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuya Orii 1-5-1, Taito, Taito-ku, Tokyo Inside Tokyo Magnetic Printing Co., Ltd. (72) Inventor Yasutoshi Fujita 1-3-1, Nihonbashi, Chuo-ku, Tokyo (72) Inventor Masao Yamaguchi 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside T-DC Corporation (72) Inventor Masahiro Sasaki 1-13-1 Nihonbashi, Chuo-ku, Tokyo F term in the company (reference) 5D033 CA05 DA01

Claims (5)

[Claims] A free abrasive slurry composition for polishing a composite material in which different hardness materials are mixed, comprising abrasive particles, a dispersion medium, a compound having at least one alcoholic hydroxyl group, and optionally a dispersant. A free abrasive slurry composition comprising: 2. The compound having an alcoholic hydroxyl group is represented by the following structural formula (I): R ¹ —OH (I) (R ¹ is an alkyl group having 4 to 18 carbon atoms, an alkenyl group, an alkynyl group, an alkyl group) The free abrasive slurry composition according to claim 1, which is a primary to tertiary alcohol represented by an aryl group or an aryl group. 3. The compound having an alcoholic hydroxyl group is represented by the formula (II): ## STR2 ## R ² O— (C _n H _{2n + 1} O) _m H (II) (where R ² has 1 to 18 carbon atoms) The alkyl group, the alkenyl group, the alkynyl group, the alkylaryl group or the aryl group, wherein n represents 2 to 4 and m represents 1 to 4). Free abrasive slurry composition. 4. The compound having an alcoholic hydroxyl group is represented by the structural formula (III): ## STR3 ## R ³ COO— (C _n H _{2n + 1} O) _m H (III) (where R ³ has 1 to 18 carbon atoms) Wherein n is 2 to 4,
m represents 1-4. The free abrasive slurry composition according to claim 1, which is a polyoxyalkylene monoester compound represented by the formula: 5. A method for manufacturing a thin-film magnetic head, comprising a step of polishing a surface serving as an air bearing surface of a thin-film magnetic head, wherein the polishing is performed by any one of claims 1 to 4. 13. A method for polishing a thin-film magnetic head using the free abrasive grain slurry composition described in the above section.