JP2017226770A - Cleaning agent for glass substrate for electronic material, and production method of glass substrate for electronic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning agent for a magnetic disk substrate, which has very high cleaning performance for abrasives and polishing debris and causes little surface roughness of the substrate after the cleaning.SOLUTION: The cleaning agent for a glass substrate for an electronic material comprises an organic alkali (A), an inorganic alkali (B), a chelating agent (C) and water, where the organic alkali (A) is a compound represented by the following general formula (1) and the cleaning agent for a glass substrate for an electronic material satisfies the following mathematical formulas (1) to (4).SELECTED DRAWING: None

Description

The present invention relates to a glass substrate cleaning agent for electronic materials and a method for producing a glass substrate for electronic materials.
More specifically, in the manufacture of a magnetic disk substrate, a cleaning agent that is suitable for removing abrasive grains and polishing debris after polishing of the surface and has less surface roughness, and manufacturing a glass substrate for electronic materials using the cleaning agent. Regarding the method.

  Electronic materials, especially magnetic disks, are becoming smaller and higher capacity year by year, and the flying height of magnetic heads is becoming smaller. Therefore, in the manufacturing process of the glass substrate for electronic materials, there is a demand for a substrate in which abrasive grains, polishing scraps, and the like do not remain. Further, improvement of surface accuracy (reduction of surface roughness, slight waviness, scratches, pits, etc.) is also demanded.

The glass substrate manufacturing process for electronic materials includes a substrate process (1) which is a process for producing a flattened substrate and a media process (2) which is a process for sputtering a magnetic layer on the substrate.
Of these, in the substrate process (1), polishing with a slurry containing abrasive grains is performed for planarization of the substrate, and then particles such as the slurry and generated polishing debris are rinsed and washed, and further removed by rinsing. The missing particles are cleaned and removed completely in a subsequent cleaning process.

By the way, with the recent increase in recording density of magnetic disks, studies using two or more stages of polishing processes have been made. That is, in the first stage polishing, polishing is performed mainly for the purpose of removing relatively large undulations, large pits and other surface defects on the substrate surface, and while the target surface roughness is achieved by the second stage polishing, It uses a method of removing fine scratches and pits.
If the abrasive grains and polishing debris used in the polishing process remain on the surface of the substrate obtained in the first stage polishing, most of them are removed in the second stage polishing process. What remains without being broken becomes a defect.
Further, the residual abrasive grains and polishing debris in the first stage cause scratches during the second stage polishing process and have an adverse effect.
In order to solve these problems, abrasive grains and polishing debris are removed at the end of the polishing process performed in each stage, and such residues are attached to the substrate before the second stage polishing process. In order to remove such residues, a high-performance cleaning agent has become necessary.

  On the other hand, in the media step (2), in order to uniformly sputter the magnetic layer on the substrate, receiving cleaning is appropriately performed. Even in this acceptance cleaning, there is a problem in that removal of chemicals (slurry, detergent, etc.) used in the cleaning process and particles generated in the cleaning process is not sufficient, and high cleaning performance is required.

  Conventionally, alkaline detergents with high pH have been proposed for these purposes. For example, a method (Patent Document 1) for improving the removability of colloidal silica using a cleaning agent containing an inorganic alkali and aldonic acid and having a pH of 10 or more has been proposed.

However, although the cleaning agent of Patent Document 1 has a certain cleaning power, the surface roughness of the surface of the target glass substrate increases after cleaning. In order to increase the recording density of magnetic disks, it is expected that surface accuracy will be increased (for example, suppressing surface roughness) in the future. However, these cleaning agents have a large surface roughness after cleaning. It is difficult to increase the recording density.
In addition, a phosphonic acid chelating agent, an anionic surfactant, and a nonionic surfactant are blended at a specific concentration ratio, and a detergent having a pH of 5 or less at 25 ° C. when diluted with pure water to 2% is used. A method of cleaning cerium oxide or colloidal silica (Patent Document 2) has also been proposed.

JP 2010-086563 A JP2012-219186A

However, although the cleaning agent of Patent Document 2 has a certain effect in suppressing surface roughness, the cleaning power is weak and is insufficient for the level required for recent cleaning.
Accordingly, an object of the present invention is to provide a glass substrate cleaning agent for electronic materials that has a very high cleaning performance for abrasive grains and polishing scraps and that has little surface roughness after cleaning, and a method for manufacturing a glass substrate for electronic materials. To do.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object. That is, the present invention is a glass substrate cleaning agent for electronic materials containing an organic alkali (A), an inorganic alkali (B), a chelating agent (C) and water, wherein the organic alkali (A) is represented by the following general formula ( 1) A glass substrate cleaning agent for electronic materials, wherein the glass substrate cleaning agent for electronic materials satisfies the following mathematical formulas (1) to (4).
[Wherein, R ^{1 to} R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms, an alkylene group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms, and X ⁻ represents an anion group. It is. ]
[pH] ≦ 0.020 × [Si] +12.736 (1)
[pH] ≦ 0.109 × [Si] +11.047 (2)
[pH] ≧ −0.060 × [Si] +11.455 (3)
[pH] ≧ 0.023 × [Si] +8.416 (4)
However, [Si] (ppb) represents the amount of Si ions eluted from one magnetic disk substrate per unit time. [pH] represents the pH of the glass substrate cleaning agent for electronic materials at 25 ° C.

  The glass substrate cleaning agent for electronic materials and the method for manufacturing a glass substrate for electronic materials of the present invention are excellent in cleaning properties for fine abrasive grains and polishing debris that are problematic in the manufacturing process of the glass substrate for electronic materials, and after cleaning. There is little surface roughness of the substrate.

  The glass substrate cleaner for electronic materials of the present invention contains an organic alkali (A), an inorganic alkali (B), a chelating agent (C) and water.

  In the present invention, the glass substrate for an electronic material includes a glass substrate for a magnetic disk, a glass substrate for a flat panel display, a glass substrate for a photomask, an optical lens, a glass substrate for a thin film solar cell, or a semiconductor substrate. From the viewpoint of suppressing deterioration, a glass substrate for hard disk is preferable.

The organic alkali (A) in the present invention is a compound represented by the general formula (1).
R ^{1 to} R ⁴ in the general formula (1) are an alkyl group having 1 to 20 carbon atoms, an alkylene group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms, and more specifically a methyl group or an ethyl group. Propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl Group, eicosyl group, methylidene group, ethylidene group, propylidene group, butylidene group, pentylidene group, hexylidene group, heptylidene group, octylidene group, nonylidene group, decylidene group, undecylidene group, dodecylidene group, tridecylidene group, tetradecylidene group, pentadecylidene group Hexadecylidene group, hep Examples include decylidene group, octadecylidene group, nonadecylidene group, eicosilidene group, benzyl group, etc., and from the standpoint of rough surface of the substrate after cleaning, and preferably from methyl group, ethyl group. It is a group.

X in the general formula (1) ^- is an anion group washing, fluoride, chloride, bromide, iodide, hydroxide, sulfate, acetate, hydrogen sulfate, borohydrides, polyhalide, and the like, for fine abrasive grains and polishing debris From the viewpoint of excellent properties and rough surface of the substrate after cleaning, hydroxide is preferred.

Specific examples of the compound represented by the general formula (1) include tetramethylammonium hydroxide (hereinafter abbreviated as TMAH), tetramethylammonium bromide, tetramethylammonium chloride, tetramethylammonium iodide, tetramethylammonium borohydride. Tetramethylammonium fluoride, tetramethylammonium dichloroiodate, tetramethylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, ethyltrimethylammonium iodide, tetramethylammonium perchlorate, tetramethylammonium sulfate, Triethylmethylammonium chloride, trimethylvinylammonium bromide, tetramethylammonium acetate, tetraethylammonium Um hydroxide (hereinafter abbreviated as TEAH), tetramethylammonium hydrogen sulfate, trimethylpropylammonium bromide, tetraethylammonium bromide, tetraethylammonium chloride, tetraethylammonium iodide, tetraethylammonium borohydride, hexyltrimethylammonium bromide, decyltrimethylammonium chloride Decyltrimethylammonium bromide, n-octyltrimethylammonium bromide, n-octyltrimethylammonium chloride, tetrapropylammonium hydroxide, trimethylnonylammonium bromide, dodecyltrimethylammonium bromide, ethyltripropylammonium iodide, hexadecyltrimethylammonium hydroxide, F Sadecyltrimethylammonium hydroxide, dodecyltrimethylammonium chloride, tetrapropylammonium iodide, tetrapropylammonium bromide, tetradecyltrimethylammonium bromide, trimethyltetradecylammonium chloride, didecyldimethylammonium bromide, dimethyldioctylammonium bromide, hexadecyltrimethylammonium Bromide, hexadecyltrimethylammonium chloride, hexyldimethyloctylammonium bromide, heptadecyltrimethylammonium bromide, tetrabutylammonium hydroxide (hereinafter abbreviated as TBAH), trimethylstearylammonium chloride, trimethylstearylammonium bromide, dilauryldimethyl Ammonium bromide, didodecyldimethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium fluoride, tetraamylammonium iodide, tetraamylammonium fluoride, tetraamylammonium chloride, tetraamylammonium hydroxide, tetra Amylammonium bromide, tetrahexylammonium hydroxide, tetrahexylammonium chloride, tetrahexylammonium bromide, tetrahexylammonium iodide, tetraheptylammonium hydroxide, tetraheptylammonium chloride, tetraheptylammonium bromide, tetraheptylammonium iodide, tetraheptyl Ammonium full Orido, tetrapentylammonium hydroxide, tetrapentylammonium chloride, tetrapentylammonium bromide, tetrapentylammonium iodide, tetrapentylammonium fluoride, tetrahexylammonium hydroxide, tetrahexylammonium chloride, tetrahexylammonium bromide, tetrahexylammonium iodide Tetrahexylammonium fluoride, tetraheptylammonium hydroxide, tetraheptylammonium chloride, tetraheptylammonium bromide, tetraheptylammonium iodide, tetraheptylammonium fluoride, tetraoctylammonium hydroxide, tetraoctylammonium chloride, tetraoctylammonium Bromide, tetra-octyl ammonium iodide, tetra-octyl ammonium fluoride and the like.

As the organic alkali (A) in the present invention, TMAH, TEAH, and TBAH are preferable from the viewpoint of the cleanability of the glass substrate cleaner for electronic materials and the surface roughness of the glass substrate for electronic materials.

Examples of the inorganic alkali (B) in the present invention include potassium hydroxide and sodium hydroxide.

  Of these, potassium hydroxide is preferred from the viewpoint of the cleanability of the glass substrate cleaner for electronic materials.

As the chelating agent (C) in the present invention, a chelating agent (C-1), phosphonic acid (salt) group or phosphoric acid (salt) group containing a carboxyl group and / or a carboxylate group in the molecule is contained in the molecule. Examples thereof include a chelating agent (C-2) and other chelating agents (C-3).

  As the chelating agent (C-1) containing a carboxyl group and / or a carboxylate group in the molecule, a hydroxycarboxylic acid having a hydroxyl group and / or a salt thereof (C-11) and a carboxylic acid having no hydroxyl group and / or There is its salt (C-12). Examples of the hydroxycarboxylic acid and / or its salt (C-11) include citric acid (salt), lactic acid (salt), gallic acid (salt) and tartaric acid (salt). Carboxylic acids having no hydroxyl group and / or salts thereof (C-12) include ethylenediaminetetraacetic acid (hereinafter abbreviated as EDTA) (salt), diethylenetriaminepentaacetic acid (hereinafter abbreviated as DTPA) (salt), hydroxyethyl- Iminodiacetic acid (hereinafter abbreviated as HIDA) (salt), 1,2-diaminocyclohexanetetraacetic acid (hereinafter abbreviated as DCTA) (salt), triethylenetetraminehexaacetic acid (hereinafter abbreviated as TTHA) (salt), nitrilo Triacetic acid (hereinafter abbreviated as NTA) (salt), β-alanine diacetate (salt), aspartate diacetate (salt), methylglycine diacetate (salt), iminodisuccinic acid (salt), serine diacetate (salt), asparagine Acid (salt) and glutamic acid (salt), pyromellitic acid (salt), benzopolycarboxylic acid (salt), cyclopentanetetra Rubonic acid (salt), carboxymethyloxysuccinate, oxydisuccinate, maleic acid derivative, oxalic acid (salt), malonic acid (salt), succinic acid (salt), glutaric acid (salt), adipic acid (salt) ) And the like.

  Examples of the chelating agent (C-2) containing a phosphonic acid (salt) group or phosphoric acid (salt) group in the molecule include methyldiphosphonic acid (salt), aminotri (methylenephosphonic acid) (salt), 1-hydroxy Ethylidene-1,1-diphosphonic acid (salt) (hereinafter abbreviated as HEDP), nitrilotrismethylenephosphonic acid (salt) (hereinafter abbreviated as NTMP), ethylenediaminetetra (methylenephosphonic acid) (salt), hexamethylenediaminetetra (Methylenephosphonic acid) (salt), propylenediaminetetra (methylenephosphonic acid) (salt), diethylenetriaminepenta (methylenephosphonic acid) (salt), triethylenetetraminehexa (methylenephosphonic acid) (salt), triaminotriethylamine hexa ( Methylenephosphonic acid) (salt), trans-1,2-cyclohexanedi Mintetra (methylenephosphonic acid) (salt), glycol ether diaminetetra (methylenephosphonic acid) (salt) and tetraethylenepentamine hepta (methylenephosphonic acid) (salt), metaphosphoric acid (salt), pyrophosphoric acid (salt), tripolyline Examples include acid (salt) and hexametaphosphoric acid (salt).

  Other chelating agents (C-3) include N, N′-bis (salicylidene) -1,2-ethanediamine, N, N′-bis (salicylidene) -1,2-propanediamine, and N, N ′. -Bis (salicylidene) -1,3-propanediamine and N, N′-bis (salicylidene) -1,4-butanediamine are exemplified.

  Among the chelating agents (C) in the present invention, a chelating agent containing a carboxyl group and / or a carboxylate group in the molecule (C-1) is preferable from the viewpoint of improving the detergency of the glass substrate cleaning agent for electronic materials. ) And a chelating agent (C-2) containing a phosphonic acid (salt) group or phosphoric acid (salt) group in the molecule, and more preferable are tartaric acid, citric acid (salt), EDTA (salt), and DTPA. (Salt), HIDA (salt), NTA (salt), NTMP (salt), HEDP (salt), ethylenediaminetetramethylenephosphonic acid (salt), pyrophosphoric acid (salt) and the like. Particularly preferred are HEDP (salt), NTMP (salt), ethylenediaminetetramethylenephosphonic acid (salt), citric acid (salt), DTPA (salt), and HIDA (salt).

  Examples of the water in the present invention include ultrapure water, ion exchange water, RO water, and distilled water, and ultrapure water is preferable from the viewpoint of cleanliness.

The glass substrate cleaner for electronic materials of the present invention satisfies the following mathematical formulas (1) to (4). When the following mathematical formulas (1) to (4) are not satisfied, the cleaning property of the glass substrate cleaning agent for electronic materials is low, and the surface of the electronic material after cleaning is rough.
[pH] ≦ 0.020 × [Si] +12.736 (1)
[pH] ≦ 0.109 × [Si] +11.047 (2)
[pH] ≧ −0.060 × [Si] +11.455 (3)
[pH] ≧ 0.023 × [Si] +8.416 (4)
However, in the active ingredient concentration when used as a cleaning liquid, [Si] (ppb) represents the amount of Si ions eluted from one magnetic disk substrate per unit time. [pH] represents the pH of the magnetic disk substrate cleaning agent at 25 ° C.

In the glass substrate cleaning agent for electronic materials of the present invention, the substrate is cleaned with a cleaning agent in which organic alkali (A), inorganic alkali (B), and chelating agent (C) are adjusted so as to satisfy the formulas (1) to (4). As a result, a substrate having a high pH and a high amount of Si ions (good cleanability) and a reduced Ra can be produced.

In order for the glass substrate cleaner for electronic materials of this invention to satisfy | fill numerical formula (1)-(4), as an adjustment method, organic alkali (A), inorganic alkali (B), and chelate in the glass substrate cleaner for electronic materials It is preferable to adjust so that the content rate of an agent (C) may satisfy | fill following numerical formula (5)-(8).
(A) ≦ −2.1 × (B) +1.3 (5)
(A) ≧ −0.5 × (B) +0.3 (6)
(A) ≧ 0.8 × (B) −0.3 (7)
0.0 <(C) ≦ 0.7 (8)

The Si ion elution amount test in the glass substrate cleaner for electronic materials of the present invention can be measured as follows.
<Si ion elution amount test>
One 2.5-inch glass substrate for a hard disk was immersed in a cleaning solution diluted to 3% by weight and tested under the following conditions.
Liquid volume: 100g
Temperature: 25 ° C
Immersion time: After 24 hours of testing, the substrate was taken out to obtain a test solution. The emission intensity of Si was measured using an ICP emission analyzer (Varian, 730-ES), and the Si concentration in the test solution was quantified.

  The pH of the cleaning agent aqueous solution diluted to 3% by weight at 25 ° C. in the present invention is preferably 9.0 to 14.0, and more preferably 10.0 to 14.0 from the viewpoint of reducing organic foreign matter residues. And particularly preferably 11.0 to 13.0. In addition, pH is measured at the measurement temperature of 25 degreeC using a pH meter (Horiba Ltd. make, F-71).

  In order to improve the cleaning property, a surfactant (D), a rust preventive agent (E) and the like can be appropriately blended with the magnetic disk substrate cleaning agent of the present invention in accordance with the object to be cleaned.

Examples of the surfactant (D) include a nonionic surfactant (D-1), an anionic surfactant (D-2), and an amphoteric surfactant (D-3).
As nonionic surfactant (D-1), as alkylene oxide addition type nonionic surfactant (D-1a), polyhydric alcohol type nonionic surfactant (D-1b), and monovalent surfactant Examples thereof include alkylene oxide adducts (D-1c) of alkylamines.

  As (D-1a), higher alcohol (8 to 18 carbon atoms) alkylene (2 to 4 carbon atoms) oxide (1 to 30 moles added per active hydrogen) adduct, alkyl (1 to 12 carbon atoms) ) Phenolethylene oxide (addition moles 1-30 per active hydrogen) adduct, fatty acid (carbon number 8-18) ethylene oxide (addition moles 1-30 per active hydrogen) adduct, aliphatic Alkylene oxide adducts of amines (6 to 24 carbon atoms) (addition moles 1 to 30 per active hydrogen), polypropylene glycol (molecular weight 200 to 4000) ethylene oxide (addition moles 1 to active hydrogen 1 50) Adduct, and polyoxyethylene (1-30 added moles per active hydrogen) alkyl (1-20 carbon atoms) allyl ether, sol Polyhydric (2 to 8 or more) alcohols (carbon number 2) such as tan monolaurate ethylene oxide (addition mole number 1-30) adduct, sorbitan monooleate ethylene oxide (addition mole number 1-30) adduct, etc. To 30) fatty acid (carbon number 8 to 24) ester ethylene oxide adduct (added mole number 1 to 30 per active hydrogen).

  As (D-1b), fatty acid (carbon) having a polyvalent (2 to 8 or more) alcohol (2 to 30 or more carbon atoms) such as glycerol monostearate, glycerol monooleate, sorbitan monolaurate, sorbitan monooleate, etc. 8-24) Fatty acid alkanolamides, such as ester, lauric acid monoethanolamide, lauric acid diethanolamide, etc. are mentioned.

  Examples of (D-1c) include alkylene oxide adducts of aliphatic amines having 8 to 24 carbon atoms. Aliphatic amines include primary amines or secondary amines. The starting aliphatic amine may be linear, branched or cyclic, and may have a saturated or unsaturated bond.

  Examples of the anionic surfactant (D-2) include a high molecular weight anionic surfactant (D-2a) and a low molecular weight anionic surfactant (D-2b).

  Polymeric anionic surfactant (D-2a) includes sulfonic acid (salt) group, sulfate ester (salt) group, phosphate ester (salt) group, phosphonic acid (salt) group and carboxylic acid (salt) Examples thereof include a polymeric anionic surfactant having at least one group selected from the group consisting of groups and having a Mw of 1,000 to 800,000. The polymer type anionic surfactant usually has at least two repeating units in one molecule. Specific examples of (D-2a) include the following (D-2a-1) to (D-2a-5).

(D-2a-1) a polymeric anionic surfactant having a sulfonic acid (salt) group:
Polystyrene sulfonic acid, styrene / styrene sulfonic acid copolymer, poly {2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid}, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid / Styrene copolymer, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid / acrylamide copolymer, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid / (meth) acrylic acid co Polymer, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid / (meth) acrylic acid / acrylamide copolymer, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid / styrene / Acrylamide copolymer, 2- (meth) acryloylamino-2,2-dimethyl eta Sulfonic acid / styrene / (meth) acrylic acid copolymer, naphthalene sulfonic acid formaldehyde condensate, methyl naphthalene sulfonic acid formaldehyde condensate, dimethyl naphthalene sulfonic acid formaldehyde condensate, anthracene sulfonic acid formaldehyde condensate, melamine sulfonic acid formaldehyde condensate And aniline sulfonic acid-phenol-formaldehyde condensate, etc .;

(D-2a-2) Polymeric anionic surfactant having a sulfate (salt) group:
Poly {2-hydroxyethyl (meth) acrylate sulfate}, 2-hydroxyethyl acrylate / 2-hydroxyethyl acrylate sulfate copolymer and 2-hydroxyethyl methacrylate / 2-hydroxyethyl methacrylate sulfate copolymer, poly { 2-hydroxyethyl (meth) acrylate} sulfated ester, poly {(meth) acryloyloxypolyoxyalkylene sulfate}, (meth) acryloyloxypolyoxyalkylene sulfate / acrylic acid copolymer and cellulose, methylcellulose or ethylcellulose Sulfated product of

(D-2a-3) Polymeric anionic surfactant having a phosphate ester (salt) group:
Poly {2-hydroxyethyl (meth) acrylate phosphate}, 2-hydroxyethyl acrylate / 2-hydroxyethyl acrylate phosphate copolymer and 2-hydroxyethyl methacrylate / 2-hydroxyethyl methacrylate phosphate copolymer , Phosphoric acid ester of poly {2-hydroxyethyl (meth) acrylate}, poly {(meth) acryloyloxypolyoxyalkylene phosphoric acid ester}, (meth) acryloyloxy polyoxyalkylene phosphoric acid ester / acrylic acid copolymer And phosphoric acid ester of cellulose, methylcellulose or ethylcellulose;

(D-2a-4) Polymeric anionic surfactant having a phosphonic acid (salt) group:
Poly {(meth) acryloyloxyethyl phosphate}, 2-hydroxyethyl acrylate / acryloyloxyethyl phosphate copolymer and 2-hydroxyethyl methacrylate / methacryloyloxyethyl phosphate copolymer, naphthalenephosphonic acid formaldehyde condensate, methylnaphthalenephosphonic acid Formaldehyde condensate, dimethylnaphthalenephosphonic acid formaldehyde condensate, anthracene phosphonic acid formaldehyde condensate, aniline phosphonic acid-phenol-formaldehyde condensate and the like;

(D-2a-4) Polymeric anionic surfactant having a carboxylic acid (salt) group:
Poly (meth) acrylic acid, (meth) acrylic acid-maleic acid copolymer, (meth) acrylic acid-itaconic acid copolymer, (meth) acrylic acid-fumaric acid copolymer, (meth) acrylic acid / acetic acid Vinyl copolymer and 2-hydroxyethyl methacrylate / (meth) acrylic acid copolymer, poly {2-hydroxyethyl (meth) acrylate} carboxymethylated product, carboxymethylcellulose, carboxymethylmethylcellulose, carboxymethylethylcellulose, benzoic acid formaldehyde Condensates and benzoic acid-phenol-formaldehyde condensates and the like.

  The Mw of (D-2a) is preferably from 1,000 to 800,000, more preferably from 1,200 to 400,000, particularly preferably 1, from the viewpoints of particle reattachment prevention and low foaming properties. 500 to 80,000, most preferably 2,000 to 40,000.

As the low molecular type anionic surfactant (D-2b), a low molecular type sulfonic acid type surfactant (D-2b-1), a low molecular type sulfate ester type surfactant (D-2b-2), Low molecular weight fatty acid surfactant (D-2b-3) and low molecular phosphate ester surfactant (D-2b-4) have a molecular weight (Mw or molecular weight calculated based on structure) of 1, And anionic surfactants of less than 000.
Among the anionic surfactants, the sulfonic acid surfactant (D-2b-1) is a sulfosuccinic acid (mono, di) ester (salt) of an alcohol having 6 to 24 carbon atoms, an 8 to 24 carbon atoms. α-olefin sulfone oxide (salt), alkylbenzene sulfonic acid (salt) having an alkyl group having 8 to 14 carbon atoms, petroleum sulfonate (salt), toluene sulfonic acid (salt), xylene sulfonic acid (salt), and cumene sulfone Examples include acids (salts). Specific examples of (D-2b-1) include dioctylsulfosuccinic acid (salt), paratoluenesulfonic acid (salt), orthotoluenesulfonic acid (salt), metaxylenesulfonic acid (salt), and paraxylenesulfonic acid (salt). ) And the like.

  Examples of the low-molecular-weight sulfate ester surfactant (D-2b-2) include sulfuric acid esters (salts) of aliphatic alcohols having 8 to 18 carbon atoms, ethylene oxides 1 to 10 of aliphatic alcohols having 8 to 18 carbon atoms. Mole adduct sulfates (salts), sulfated oils (salts), sulfated fatty acid esters (salts), sulfated olefins (salts), and the like. Specific examples of (D-2b-2) include 2-ethylhexanol sulfate (salt), octanol sulfate (salt), 1,10-decandiol disulfate (salt), and ethylene oxide of lauryl alcohol (5 Mol) adduct disulfate (salt) and the like.

  Examples of the low molecular weight fatty acid surfactant (D-2b-3) include fatty acid (salt) having 8 to 18 carbon atoms and ether carboxylic acid (salt) of an aliphatic alcohol having 8 to 18 carbon atoms. Specific examples of (A-2b-3) include n-octanoic acid (salt), 2-ethylhexanoic acid (salt), n-nonanoic acid (salt), isononanoic acid (salt), oleic acid (salt) and Examples include stearic acid (salt).

  Examples of the low molecular phosphate ester surfactant (D-2b-4) include phosphoric acid (mono, di) esters (salts) of higher alcohols having 8 to 24 carbon atoms and higher alcohols having 8 to 24 carbon atoms. Examples include phosphoric acid (mono, di) esters (salts) of alkylene oxide adducts. Specific examples of (D-2b-4) include lauryl alcohol monophosphate (salt), phosphate monoester (salt) of ethylene oxide (5 mol) adduct of lauryl alcohol, and octyl alcohol diphosphate (salt). Etc.

  There are no particular limitations on the counter ion when (D-2) forms a salt, but usually alkali metal (sodium and potassium) salts, ammonium salts, primary amines (alkylamines such as methylamine, ethylamine and butylamine, Monoethanolamine and guanidine etc.) salt, secondary amine (dialkylamine such as dimethylamine, diethylamine and dibutylamine and diethanolamine etc.) salt, tertiary amine {trialkylamine such as trimethylamine, triethylamine and tributylamine, triethanolamine, N-methyldiethanolamine and 1,8-diazabicyclo [5.4.0] -7-undecene (DBU), 1,5-diazabicyclo [4.3.0] -5-nonene (DBN) or 1,4- Diazabicyclo [2.2.2] O Tan (DABCO), 1H imidazole, 2-methyl-1H-imidazole, 2-ethyl-1H-imidazole, 4,5-dihydro-1H imidazole, 2-methyl-4,5-dihydro-1H imidazole, 1,4 5,6-tetrahydro-pyrimidine, 1,6 (4) -dihydropyrimidine etc.} salt and quaternary ammonium salt (tetraalkyl ammonium etc.) salt. Of these, ammonium salts, primary amine salts, secondary amine salts, tertiary amine salts and quaternary ammonium salts are preferred from the viewpoint of metal contamination on the substrate, and tertiary amines are particularly preferred. Salts and quaternary ammonium salts, most preferred are DBU, DBN, DABCO, N-methyldiethanolamine, 1H-imidazole, 2-methyl-1H-imidazole and 2-ethyl-1H-imidazole.

Among the anionic surfactants (D-2), the polymer type anionic surfactant (D-2a) and the low molecular weight sulfonic acid type surfactant (C) are preferred from the viewpoint of preventing the reattachment of particles. -2b-1), low-molecular-weight sulfate ester surfactant (D-2b-2) and low-molecular-weight fatty acid surfactant (C-1b-3), more preferably (D-2a) , (D-2b-1) and (D-2b-2), particularly preferred are polyacrylic acid (salt), polystyrene sulfonic acid (salt), salt of naphthalene sulfonic acid formalin condensate, acrylamide-2-methylpropane Salt of sulfonic acid / acrylic acid copolymer, salt of methacryloyloxypolyoxyalkylene sulfate / acrylic acid copolymer, octylbenzenesulfonic acid (salt), paratoluenesulfonic acid (salt) Meta-xylene sulfonic acid (salt) and 2-ethylhexanol sulfate (salt).
(D-2) may be used alone or in combination of two or more.

  As amphoteric surfactant (D-3); betaine-type amphoteric surfactant (D-3a) {for example, alkyl (C1-30) dimethylbetaine, alkyl (C1-30) amide alkyl (carbon number) 1-4) Dimethylbetaine, alkyl (C1-30) dihydroxyalkyl (C1-30) betaine, sulfobetaine type, etc.}; amino acid type amphoteric surfactant (C-3b) {for example, alanine type [ Alkyl (C1-C30) aminopropionic acid type, alkyl (C1-C30) iminodipropionic acid type, etc.], glycine type [alkyl (C1-C30) aminoacetic acid type, etc.]}; and aminosulfone Salt type amphoteric surfactant (D-3c) {for example, alkyl (having 1 to 30 carbon atoms) taurine type amphoteric surfactant};

Of these surfactants (D), a polymer anionic surfactant is preferably blended from the viewpoint of preventing reattachment of particles.
Moreover, it is preferable to mix | blend a nonionic surfactant from a viewpoint of the washing | cleaning property with respect to organic substance stains, such as a coolant.

  The content of the surfactant (D) is preferably 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, based on the weight of the magnetic disk substrate cleaning agent from the viewpoint of detergency. .

  Another embodiment of the present invention is a method of manufacturing a magnetic disk substrate including a step of cleaning a glass substrate for electronic material using the above-described glass substrate cleaning agent for electronic material, from the viewpoint of cleanability and surface roughness. It is particularly suitable for a method for producing a glass substrate for a hard disk.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these.

[Production Example 1] Synthesis of polyacrylic acid DBU salt A reaction vessel capable of temperature adjustment and stirring was charged with 300 parts of isopropyl alcohol and 100 parts by weight of ultrapure water, and the temperature was raised to 75 ° C after purging with nitrogen. Under stirring, 407 parts by weight of a 75% by weight aqueous solution of acrylic acid and 95 parts by weight of a 15% by weight isopropyl alcohol solution of dimethyl 2,2′-azobisisobutyrate were simultaneously added dropwise over 3.5 hours. After completion of the dropwise addition, the mixture was stirred at 75 ° C. for 5 hours, and then ultrapure water was intermittently added so that the system did not solidify, and the mixture of water and isopropyl alcohol was distilled off until isopropyl alcohol could not be detected. The obtained polyacrylic acid aqueous solution is neutralized with diazabicycloundecene (DBU) (450 parts by weight) until the pH becomes 7, and the concentration is adjusted with ultrapure water to thereby adjust the concentration of polyanion surfactant. A 40% by weight aqueous solution of an acrylic acid DBU salt was obtained. The weight average molecular weight of the synthesized polyacrylic acid DBU salt was measured at 40 ° C. using polyethylene oxide as a standard substance by gel permeation chromatography (hereinafter abbreviated as GPC). ) Manufactured by HLC-8120, column: TSKgel G5000 PWXL, G3000 PW XL manufactured by Tosoh Corporation, detector: differential refractometer detector built in the main body of the apparatus, eluent: 0.2 M anhydrous sodium sulfate, 10% acetonitrile buffer, Eluent flow rate: 0.8 ml / min, column temperature: 40 ° C., sample: 1.0 wt% eluent solution, injection amount: 100 μl, standard materials: TSK SE-30, SE-15 manufactured by Tosoh Corporation The measurement was performed under the conditions of SE-8 and SE-5.
The weight average molecular weight (Mw) by GPC method was 10,000.

Examples 1-9 and Comparative Examples 1-6
Each component was blended so as to have the composition shown in Table 1, and stirred at 25 ° C. and a magnetic stirrer at 40 rpm for 20 minutes to obtain the cleaning agent of the present invention and the cleaning agent for comparison.
The cleaning agent was further diluted to 3% by weight with ultrapure water to prepare a sample solution for performance test.

Various performance evaluation tests for the cleaning properties and surface roughness of the cleaning agent were performed by the following methods.
This evaluation was performed in a clean room of class 1,000 (FED-STD-209D, US Federal Standard, 1988) to prevent contamination from the atmosphere.

<Detergency test>
A 2.5 inch hard disk glass substrate was polished under the following conditions using commercially available colloidal silica (“COMPOL20” manufactured by Fujimi Incorporated, particle size of about 20 nm) as an abrasive.
Polishing equipment: “NFD-4BL” manufactured by Nano Factor
Slurry supply speed: 50 mL / min Load: 30 g weight / cm ²
Rotation speed: surface plate 30rpm, gear 20rpm
Polishing time: 10 minutes

After the substrate was polished and rinsed with ultrapure water for 1 minute, the substrate was removed from the polishing apparatus, immersed in an ultrasonic cleaner (output: 200 kHz) filled with the above sample solution, and washed at 25 ° C. for 10 minutes. The substrate after washing was taken out from the washing machine, washed with running water for 1 minute, and dried with nitrogen gas to obtain a substrate for evaluation.
Observe with a surface inspection device (“Micro-Max VMX-7100” manufactured by Vision Cytec Co., Ltd.) that illuminates the surface of the glass substrate for hard disk and amplifies the detected reflected light if there is a foreign matter of about 10 μm or more. Image analysis software “Sigmascan” was used to count the number of particles such as abrasive grains adhering to a 1 cm square on the substrate.
The blank was also washed with ultrapure water. The number of particles adhering to the substrate after cleaning at that time was 840.
The detergency test was evaluated according to the following evaluation criteria, and the evaluation results are shown in Table 1.

[Evaluation criteria for detergency test]
5: The number of particles adhering on the substrate after cleaning is less than 10% of the blank 3: The number of particles adhering on the substrate after cleaning is 10% or more and less than 50% of the blank 1: On the substrate after cleaning The number of adhering particles is 50% or more of the blank.

<Rough surface>
Using the glass substrate for hard disk used in the detergency test, the surface roughness was measured under the following conditions with an atomic force microscope (manufactured by SII Nano Technology, E-sweep).
Measurement mode: DFM (tapping mode)
Scan area: 10 μm × 10 μm
Number of scanning lines: 256 (Y-direction scanning)
Correction: With flat correction in the X and Y directions Table 1 shows the evaluation results.

  From Table 1, it can be seen that the cleaning liquids of Examples 1 to 9 have few particles remaining on the glass substrate and high cleaning performance. It can also be seen that there is little surface roughness after cleaning. On the other hand, the cleaning liquids of Comparative Examples 1 and 2 have a certain level of cleaning performance, but the substrate surface is greatly roughened after cleaning. Further, the cleaning liquids of Comparative Examples 3 and 4 have a low cleaning performance although surface roughness is suppressed as compared with the cleaning liquids of Comparative Examples 1 and 2. The cleaning liquids of Comparative Examples 4 to 6 in which [pH] and [Si] do not satisfy the mathematical formulas (1) to (4) cannot achieve both cleaning properties and surface accuracy.

  The glass substrate cleaning agent for electronic materials of the present invention can greatly improve the cleaning performance of particles on a substrate compared to conventional cleaning agents. Further, the surface roughness of the substrate after cleaning is small. Therefore, it can be used as a hard disk substrate cleaning agent whose recording density is increasing.

Claims (4)

A glass substrate cleaning agent for electronic materials containing an organic alkali (A), an inorganic alkali (B), a chelating agent (C) and water, wherein the organic alkali (A) is represented by the following general formula (1): A glass substrate cleaning agent for electronic materials, wherein the glass substrate cleaning agent for electronic materials satisfies the following mathematical formulas (1) to (4).
[Wherein, R ^{1 to} R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms, an alkylene group having 1 to 20 carbon atoms, or an aryl group having 1 to 20 carbon atoms, and X ⁻ represents an anion group. It is. ]
[pH] ≦ 0.020 × [Si] +12.736 (1)
[pH] ≦ 0.109 × [Si] +11.047 (2)
[pH] ≧ −0.060 × [Si] +11.455 (3)
[pH] ≧ 0.023 × [Si] +8.416 (4)
However, [Si] (ppb) represents the amount of Si ions eluted from one magnetic disk substrate per unit time. [pH] represents the pH of the glass substrate cleaning agent for electronic materials at 25 ° C. The organic alkali (A), inorganic alkali (B), and chelating agent (C) content in the glass substrate cleaner for electronic materials satisfies the following mathematical formulas (5) to (8): The glass substrate cleaning agent for electronic materials as described.
(A) ≦ −2.1 × (B) +1.3 (5)
(A) ≧ −0.5 × (B) +0.3 (6)
(A) ≧ 0.8 × (B) −0.3 (7)
0.0 <(C) ≦ 0.7 (8) Furthermore, the glass substrate cleaning agent for electronic materials of Claim 1 or 2 containing surfactant (D). The manufacturing method of the glass substrate for electronic materials using the glass substrate cleaning agent for electronic materials in any one of Claims 1-3.