JP5417095B2 - Cleaning composition and method for cleaning glass hard disk substrate - Google Patents

Description

  The present invention relates to a cleaning composition and a method for cleaning a glass hard disk substrate.

  In electronic devices, fine dirt tends to cause malfunction and performance degradation. Therefore, it is required to remove almost completely the dirt attached to the electronic device substrate such as a display substrate used for a semiconductor substrate, a hard disk substrate, a liquid crystal panel or the like.

Conventionally, various precision cleaning techniques have been proposed in order to achieve the required cleanliness depending on the electronic device substrate to be cleaned and the type of dirt attached to the electronic device substrate.
For example, a hard disk substrate is roughly polished with an abrasive such as cerium oxide or alumina, and then further polished with an abrasive such as colloidal silica. In particular, when polishing a glass hard disk substrate, it is common to use cerium oxide during rough polishing.
Since the abrasive grains and polishing residue generated by polishing remain on the surface of the hard disk substrate after rough polishing or finish polishing, it is necessary to remove these after each polishing.

As a method for removing residual abrasive grains and polishing residue generated by rough polishing and finish polishing, for example, an aqueous solution containing an organic acid such as malic acid or citric acid and a chelating agent was used, and the surface was plated with a metal alloy. A method for cleaning a magnetic recording medium substrate has been proposed (see Patent Document 1).
Moreover, as a cleaning composition for glass substrates, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and nonionic surfactant are used, and the mass ratio of the two is HEDP / surfactant = 1/20. A cleaning composition containing ˜1 / 5 (see Patent Document 2) and a cleaning agent containing hydroxycarboxylic acid or phosphonic acid as a chelating agent and a surfactant (see Patent Document 3) are proposed. Has been.

JP 2005-174442 A JP 2007-291328 A JP 2009-87523 A

  By the way, glass hard disks have recently been in the trend of miniaturization and high capacity, and accordingly, the surface roughness of the substrate and the slight waviness of the substrate surface are reduced in the polishing process of the glass hard disk substrate, It is required to reduce surface defects such as scratches called. Further, after polishing the surface of the substrate, abrasive grains such as abrasives and polishing residue are likely to adhere to the surface. In order to reduce the size and increase the capacity of glass hard disks, it is important to sufficiently remove these abrasive grains and polishing debris. Therefore, it is necessary to further remove abrasive grains and debris in the cleaning process. It has been.

  In particular, cerium oxide, which is suitably used as an abrasive for rough polishing a glass hard disk substrate, tends to adhere to the substrate surface as particles (fine particle contamination). Although cerium oxide adhering to the substrate is generally removed by washing the substrate before finish polishing, it has been difficult to completely remove it. Therefore, cerium oxide remains on the substrate even after finish polishing. Therefore, in order to respond to the miniaturization and increase in capacity of the glass hard disk, the cleaning composition is required to have excellent cleaning properties with respect to an abrasive such as cerium oxide.

However, in the method described in Patent Document 1, a hard disk substrate whose surface is plated with a metal alloy is a cleaning target, and a glass hard disk substrate is not a cleaning target. For this reason, although the hard disk substrate whose surface is plated with a metal-based alloy exhibits a cleaning property, it is difficult to exhibit a high cleaning property, particularly an excellent cleaning property for cerium oxide, for a glass hard disk substrate.
In addition, the cleaning compositions described in Patent Documents 2 and 3 do not necessarily satisfy the cleaning properties for cerium oxide.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cleaning composition having excellent cleaning properties against fine particle stains derived from abrasives such as cerium oxide, and a method for cleaning a glass hard disk substrate. .

  As a result of intensive studies by the present inventors, the surfactant is a substance having an excellent cleaning effect and is a component generally used in the cleaning agent, but is derived from the aggregation of an abrasive such as cerium oxide or the abrasive. We focused on promoting the adhesion of particulate contamination to the substrate. Therefore, by reducing the amount of the surfactant in the cleaning composition, the cleaning performance against fine particle stains derived from abrasives such as cerium oxide is improved, and the types and contents of each component included in the cleaning composition By defining the amount, it was found that high detergency can be maintained even if the amount of the surfactant is reduced, and the present invention has been completed.

That is, the cleaning composition of the present invention is a cleaning composition used for cleaning a glass hard disk substrate polished with an abrasive containing cerium oxide, wherein (A) component: 5 to 15 % by mass of a phosphonic acid chelating agent, (B) component: 1-10 mass% of hydroxycarboxylic acid and / or its salt, and mass ratio of said (A) component and (B) component is (A) component / (B) component = 50 is a / 50-90 / 10, a content of the surfactant is less than 1 wt% state, and are pH is 5.0 or less at 25 ° C. of diluted solution diluted to 2 wt% with pure water, pure characterized Rukoto used at a dilution of 0.1 to 20.0 wt% water.
The component (A) is preferably 1-hydroxyethane-1,1-diphosphonic acid and / or a salt thereof.
Furthermore, the component (B) is preferably glycolic acid and / or a salt thereof.

  The glass hard disk substrate cleaning method of the present invention is characterized in that the cleaning composition of the present invention is diluted to 0.1 to 20.0% by mass with pure water.

  ADVANTAGE OF THE INVENTION According to this invention, the cleaning composition which is excellent in the washing | cleaning property with respect to fine-particle dirt derived from abrasives, such as a cerium oxide, and the washing | cleaning method of glass hard disk substrates can be provided.

Hereinafter, the present invention will be described in detail.
[Cleaning composition]
The cleaning composition of the present invention is for cleaning a glass hard disk substrate polished with an abrasive containing cerium oxide, and comprises (A) component: phosphonic acid chelating agent, (B) component: hydroxycarboxylic acid and / or Or a salt thereof.

<(A) component>
The cleaning composition of the present invention contains a phosphonic acid chelating agent as the component (A).
Examples of the phosphonic acid chelating agent include 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and / or a salt thereof, nitrilotrismethyleneformic acid (NTMP) and / or a salt thereof, ethylenediaminetetramethylenephosphonic acid (EDTMP). ) And / or a salt thereof.
Examples of these phosphonic acid salts include sodium, potassium, ammonium, monoethanolamine, diethanolamine, triethanolamine, and tetramethylammonium hydroxide.

  As the phosphonic acid chelating agent, 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and / or a salt thereof is preferable in that it is more excellent in cleaning properties against abrasives, particularly fine particle stains derived from cerium oxide. Among them, 1-hydroxyethane-1,1-diphosphonic acid-4 sodium salt is preferable.

(A) Content of a component is 1-50 mass% in 100 mass% of cleaning composition, 1-20 mass% is preferable, 5-15 mass% is more preferable, and 7-12 mass% is especially. preferable.
The cerium oxide suitably used as an abrasive for rough polishing of a glass hard disk substrate usually has zero charge in water. Therefore, cerium oxide is difficult to disperse in water and easily adheres to the surface of the substrate. When the content of the component (A) is 1% by mass or more, a negative charge can be imparted to the substrate and an abrasive such as cerium oxide attached to the surface of the substrate, and the negative zeta potential can be increased. As a result, the electrostatic repulsion between the substrate and cerium oxide is increased (cerium oxide is easily dispersed), and the cerium oxide is easily separated from the substrate. In addition, once the cerium oxide is separated from the substrate, it becomes difficult to re-adhere, thereby improving the cleaning performance for cerium oxide. Furthermore, since cerium oxide can be dissolved to some extent, the cleaning properties are easily improved. On the other hand, even if the content of the component (A) exceeds 50% by mass, the improvement of the cleaning property is not limited, and the manufacturing cost is likely to be increased.

<(B) component>
The cleaning composition of the present invention contains hydroxycarboxylic acid and / or a salt thereof as component (B).
Examples of the hydroxycarboxylic acid include glycolic acid, citric acid, gluconic acid, salicylic acid, lactic acid, hydroxybutyric acid, malic acid, tartaric acid, gallic acid, hydroxyiminodiacetic acid (HIDA), hydroxyiminodisuccinic acid (HIDS), hydroxy Examples include ethylethylenediaminetriacetic acid (HEDTA), dihydroxyethylglycine (DHEG), 1,3-diamino-2-hydroxypropanetetraacetic acid (DTPA-OH), heptogluconic acid, and the like.
Examples of these salts of hydroxycarboxylic acid include sodium, potassium, ammonium, monoethanolamine, diethanolamine, triethanolamine, and tetramethylammonium hydroxide.

As the hydroxycarboxylic acid, glycolic acid, citric acid, and gluconic acid are preferable, and glycolic acid is particularly preferable in that it is more excellent in cleaning properties against abrasives, particularly fine particle stains derived from cerium oxide.
Since glycolic acid exhibits a high peeling force against fine particle stains derived from cerium oxide, the cleaning properties for cerium oxide are particularly improved. Therefore, glycolic acid and / or a salt thereof is particularly preferable as the component (B).

(B) Content of a component is 1-20 mass% in 100 mass% of cleaning composition, 1-10 mass% is preferable, 2-8 mass% is more preferable, and 4-6 mass% is especially. preferable.
If content of (B) component is 1 mass% or more, since abrasives, such as a cerium oxide, can be peeled, the detergency with respect to a cerium oxide improves especially. On the other hand, even if the content of the component (B) exceeds 20% by mass, the improvement of the cleaning property is not limited, and the manufacturing cost tends to be increased.

Since the component (B) is used in combination with the component (A) described above, the effect of removing fine particles derived from cerium oxide adhering to the substrate is enhanced. improves. However, when the content of the component (B) is larger than that of the component (A), the function of the component (A) (that is, a negative charge is imparted to the abrasive such as cerium oxide, and the cerium oxide is easily separated from the substrate. In addition, it is difficult to obtain the effect of preventing re-adhesion, and the cleaning properties with respect to the abrasive, particularly cerium oxide, tend to be reduced. Therefore, it is important that the content of the component (B) is not more than the content of the component (A).
That is, in the present invention, the mass ratio of the component (A) and the component (B) is (A) component / (B) component = 50/50 to 90/10, and 60/40 to 80/20. It is preferable.

<Surfactant>
As described above, the surfactant is a substance having an excellent cleaning effect and is a component generally used in the cleaning agent. However, the surfactant is agglomerated with an abrasive such as cerium oxide, or to a substrate of particulate contamination derived from the abrasive. Easy to promote adhesion. Therefore, as the content of the surfactant increases, the detergency with respect to the abrasive tends to decrease.
The detergent composition of the present invention may contain a surfactant, but most preferably it does not contain a surfactant. When the surfactant is contained, the content thereof is less than 1% by mass in 100% by mass of the cleaning composition, preferably 0.7% by mass or less, and more preferably 0.5% by mass or less. When the content of the surfactant is less than 1.0% by mass, an excellent cleaning property can be exhibited with respect to the abrasive, particularly cerium oxide.

Here, the “surfactant” in the present invention is a compound having a surface tension at 25 ° C. of 50 mN / m or less when diluted to 1% by mass with pure water. The surface tension is measured using a platinum plate using a surface tension meter based on the Wilhelmy method.
The surface tension tends to decrease as the number of carbon atoms of the alkyl group in the surfactant increases. Therefore, the compounds classified as surfactants in the present invention are relatively long-chain compounds having an alkyl group with 7 or more carbon atoms.

Examples of the surfactant include ionic surfactants and nonionic surfactants.
Examples of ionic surfactants include sodium dialkyl sulfosuccinate, soap, alpha olefin sulfonic acid, alkyl benzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl sulfate ester, alkyl ether sulfate ester, methyl tauric acid, alaninate, sulfosuccinic acid, sulfated oil. , Ether carboxylic acid, quaternary ammonium, imidazolinium betaine series, amidopropyl betaine series, aminodipropionic acid, alkylamine, alkylamide salts, and the like.
Examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene glycol ethers, polyoxyalkylene polyalkylaryl ethers, fatty acid esters, alkylamine EO adducts, alkylamide EO adducts, and alkylamine oxides. It is done.

<Other ingredients>
The cleaning composition of the present invention may contain other components other than the component (A), the component (B), and the surfactant as needed as long as the effects of the present invention are not impaired.
Examples of other components include solvents, pH adjusters, antifoaming agents, glycol ethers, preservatives, antioxidants, inorganic salts, and dispersants.
Examples of the solvent include pure water, alcohols such as ethanol and isopropanol, and a mixture of alcohol and water. The content of the solvent is preferably 50.0 to 99.5% by mass and more preferably 60.0 to 98.0% by mass in 100% by mass of the cleaning composition.

<Physical properties>
In the cleaning composition of the present invention, the pH at 25 ° C. of a diluted solution diluted to 2% by mass with pure water is 5.0 or less, preferably 4.0 or less, and more preferably 3.0 or less.
Under acidic conditions, abrasives, especially cerium oxide, tend to dissolve easily. Therefore, if the pH of the cleaning composition is 5.0 or less, it can be effectively cleaned in a short time while dissolving fine particle stains derived from an abrasive such as cerium oxide. Since the hard disk substrate to be cleaned of the present invention is made of glass, there is no risk of corrosion even under acidic conditions. The lower limit of pH is not particularly limited, but is preferably 1.0 or more.
The pH of the cleaning composition was measured using a pH meter (manufactured by Toa DKK, “HM-20S”) and a pH electrode (manufactured by Toa DKK, “GST-5212C”) with respect to a diluted solution at 25 ° C. Then, immersing the pH electrode and reading the indicated value after 15 seconds.

<Preparation method>
The method for preparing the cleaning composition of the present invention is not particularly limited, and can be prepared by sequentially mixing each component according to a conventional method.

As described above, the cleaning composition of the present invention is used for cleaning a glass hard disk substrate polished with an abrasive containing cerium oxide.
The cleaning composition of the present invention is excellent in cleaning properties against fine particle dirt derived from an abrasive such as cerium oxide.

The reason why such an effect is obtained is not certain but is presumed as follows.
The cleaning composition of the present invention contains 1 to 50% by mass of a phosphonic acid chelating agent as the component (A) and 1 to 20% by mass of hydroxycarboxylic acid and / or a salt thereof as the component (B). It is considered that the detergency with respect to cerium oxide is improved by dissolving an abrasive such as cerium oxide by each component. In addition, the component (A) imparts a negative charge to the substrate and cerium oxide and increases the negative zeta potential, thereby increasing the electrostatic repulsion between the substrate and cerium oxide. As a result, the cerium oxide is likely to be separated from the substrate, and once the cerium oxide is separated from the substrate, it is difficult to re-adhere, thereby improving the cleaning performance for cerium oxide.
Furthermore, by defining the content of the component (A) and the component (B) within a specific range, excellent detergency can be maintained even if the content of the surfactant is reduced to less than 1% by mass.

[Cleaning method of glass hard disk substrate]
The method for cleaning a hard disk substrate of the present invention is a method in which the cleaning composition of the present invention is diluted to 0.1 to 20.0% by mass with pure water.
If the cleaning composition is diluted to 0.1% by mass or more, it is possible to sufficiently exhibit excellent detergency against fine particle stains derived from abrasives such as cerium oxide. On the other hand, if the cleaning composition is diluted to 20.0% by mass or less, the abrasive grains and polishing debris are sufficiently removed while maintaining excellent cleaning properties against fine particle stains derived from abrasives such as cerium oxide. it can.

The cleaning means is not particularly limited, and is a method in which the cleaning composition is directly sprayed and sprayed onto a polished glass hard disk substrate to be cleaned; the glass hard disk substrate is used as a cleaning composition. Examples of the dipping method include ultrasonic treatment at the time of cleaning, and a method of rubbing with a brush.
Hereinafter, an example of the method for cleaning a glass hard disk substrate of the present invention will be specifically described.

First, the surface of the glass hard disk substrate is roughly polished with cerium oxide.
The method of rough polishing the glass hard disk substrate is not particularly limited, and examples thereof include a method of polishing the surface by pressing the substrate while supplying a polishing slurry containing an abrasive using a polishing machine.

Next, the cleaning composition of the present invention is diluted to a desired concentration, sprayed with a spray or the like, and cleaned using a cleaning brush or the like.
Further, pure water is sprayed and rinsed to remove the cleaning composition remaining on the substrate.
After rinsing the substrate with pure water, the substrate is dried by a known method to remove the pure water remaining on the substrate.

The glass hard disk substrate after the rough polishing is finish-polished using an abrasive such as colloidal silica. In that case, abrasives other than colloidal silica, for example, metal or metalloid carbides, nitrides, oxides, borides, diamonds and the like may be used in combination. Specific examples include α-alumina, silicon carbide, diamond, magnesium oxide, zinc oxide, cerium oxide, zirconium oxide, and fumed silica. When these abrasives are used in combination, the proportion of colloidal silica in 100% by mass of the abrasive is preferably 50 to 100% by mass.
The method for finish polishing a glass hard disk substrate is not particularly limited, and may be performed in the same manner as rough polishing.

The glass hard disk substrate after finish polishing may be cleaned using a known cleaning composition, or may be cleaned using the cleaning composition of the present invention. However, when using the cleaning composition of the present invention, it is preferable to dilute and use it to a desired concentration.
After cleaning with the cleaning composition, pure water is sprayed and rinsed to remove the cleaning composition remaining on the substrate.
After rinsing the substrate with pure water, the substrate is dried by a known method to remove the pure water remaining on the substrate.

  The glass hard disk substrate cleaning method is not limited to the method described above. For example, a known cleaning composition or pure water is used for cleaning after rough polishing, and the cleaning according to the present invention is performed only for cleaning after final polishing. An agent composition may be used.

As described above, according to the method for cleaning a glass hard disk substrate of the present invention, it is possible to sufficiently clean and remove the abrasives, particularly fine particle stains derived from cerium oxide, attached to the surface of the glass hard disk substrate by the polishing process. .
Therefore, the glass hard disk substrate cleaned according to the present invention is most suitable for a hard disk for the purpose of miniaturization and high capacity.

  Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples. In the following, “%” is “% by mass” unless otherwise specified.

Here, the components shown in Tables 1 and 2 used in each Example and Comparative Example are as follows.
HEDP: 1-hydroxyethane-1,1-diphosphonic acid 4Na (prepared by neutralizing “Ferox 115-A” manufactured by Lion Corporation with NaOH),
NTMP: nitrilotrismethylene phosphonic acid ("Kyrest PH-320" manufactured by Kyrest Inc.),
Glycolic acid: “Glycolic acid” manufactured by Maruwa Bussan Co., Ltd.
Citric acid: “Citric acid (deer grade)” manufactured by Kanto Chemical Co., Inc.
Gluconic acid: “Gluconic acid solution” manufactured by Kanto Chemical Co., Inc.
Surfactant: Dioctylsulfosuccinate Na (“Ripal 870P” manufactured by Lion Corporation, surface tension: 27 mN / m),
NaOH: Sodium hydroxide (“Sodium hydroxide” manufactured by Junsei Kagaku).
The “balance” shown in Tables 1 and 2 means the blending amount of pure water in the cleaning composition, adjusted so that the total amount of each component contained in the cleaning composition is 100% by mass. .

<Measurement of surface tension>
The cleaning composition was diluted to 1% with pure water (ion exchange water) to prepare a diluted solution, and the surface tension of the diluted solution at 25 ° C. was measured.
The surface tension was measured using a fully automatic surface tension meter (“KYOWA CBVP SURFACE TENSIOMETER A3” manufactured by Kyowa Kagaku Co., Ltd.) at 25 ° C. and using a platinum plate based on the Wilhelmy method.

<Measurement of pH of cleaning composition>
The cleaning composition was diluted to 2% with pure water to prepare a diluted solution, and the pH of the diluted solution at 25 ° C. was measured.
The pH is measured by immersing the pH electrode in a diluted solution at 25 ° C. using a pH meter (manufactured by Toa DK, “HM-20S”) and a pH electrode (manufactured by Toa DK, “GST-5111C”). The reading was made after reading 15 seconds.

<Evaluation of detergency>
The substrate after cleaning was irradiated with a halogen lamp, the degree of remaining cerium oxide-derived fine particles (particles) was visually observed, and the cleaning property was evaluated according to the following evaluation criteria. In addition, it means that the washing | cleaning property with respect to fine particle dirt derived from a cerium oxide is so high that dirt is removed.
(Double-circle): Fine particle | grain dirt is not observed but is very favorable.
○: Slight particulate contamination remains, but generally good.
Δ: Particulate dirt remains as a whole, but there is a part where the particulate dirt is not attached.
X: Fine particle stains are hardly removed.

[Examples 1 to 9]
In the formulation (%) shown in Table 1, each component was mixed to prepare a cleaning composition. 980 mL of pure water was put into a resin beaker containing a magnetic stirrer, and 20 mL of the cleaning composition was added while rotating the magnetic stirrer, and diluted to 2%. Table 1 shows the pH of the diluted detergent composition.

Separately, a 2.5-inch hard disk substrate made of glass was used as a substrate and immersed in a polishing slurry containing cerium oxide (average particle size: 500 nm) as an abrasive for 5 minutes.
Next, after rinsing the substrate surface with pure water, cleaning was performed by rotating the cleaning brush against both surfaces of the substrate for 10 seconds while injecting the diluted cleaning composition at 25 ° C. Thereafter, the substrate was immersed in a water tank filled with pure water, and rinsed for 10 minutes by overflowing pure water. Next, the substrate was taken out of the water tank and dried with dry air.
About the board | substrate after drying, washability was evaluated by said evaluation method. The results are shown in Table 1.

[Comparative Examples 1-8]
Glass hard disk substrates were washed in the same manner as in Examples 1 to 9, except that the components (%) shown in Table 2 were mixed to prepare a detergent composition.
About the board | substrate after drying, washability was evaluated by said evaluation method. The results are shown in Table 2.

As is apparent from Table 1, the glass hard disk substrate was washed using each of the cleaning compositions obtained in Examples 1 to 9, and as a result, the cerium oxide-derived fine particle stains adhering to the glass hard disk substrate were sufficiently removed. Was able to be washed.
In particular, when Examples 1 to 3 were compared, the case of Example 1 using glycolic acid as the component (B) showed better cleaning properties.
Moreover, when Examples 1 and 4 were compared, the case of Example 1 using HEDP as the component (A) showed better cleaning properties.
Further, when Examples 1, 5, and 6 were compared, the case of Example 1 in which the mass ratio of the component (A) to the component (B) was 2: 1 showed better cleaning properties.
Further, when Examples 1 and 9 were compared, the case of Example 1 containing no surfactant showed better cleaning properties.
From the above results, the cleaning composition of the present invention was excellent in cleaning properties against abrasives, particularly fine particle stains derived from cerium oxide.

On the other hand, as apparent from Table 2, the cleaning composition obtained in Comparative Example 1 containing no component (B) and Comparative Example 5 containing a small amount of component (B) of 0.5% was used. Detergency was inferior compared with the cleaning composition obtained in Examples 1-9.
It is obtained in Comparative Example 2 that does not contain the component (A) and Comparative Example 6 in which the content of the component (A) is as low as 0.5% and the content of the component (B) is large compared to the component (A). The cleaning composition was inferior in cleaning properties compared to the cleaning compositions obtained in Examples 1-9. In particular, in the case of Comparative Example 2 that does not contain the component (A), the detergency was significantly reduced.
The cleaning composition obtained in Comparative Examples 3 and 4 in which the content of the (B) component is large compared to the (A) component has a cleaning property compared to the cleaning composition obtained in Examples 1 to 9. It was inferior.
The cleaning composition obtained in Comparative Example 7 containing 1% of the surfactant was inferior in cleaning properties compared to the cleaning compositions obtained in Examples 1-9.
The cleaning composition obtained in Comparative Example 8 having a pH of 6.0 was inferior in cleaning properties as compared with the cleaning compositions obtained in Examples 1-9.

Claims (4)

In the cleaning composition used for cleaning a glass hard disk substrate polished with an abrasive containing cerium oxide,
Component (A): a phosphonic acid chelating agent 5-15% by weight, (B) component: hydroxy carboxylic acids and / or 1-1 contains 0 wt% of a salt thereof, and wherein components (A) and (B ) Component mass ratio is (A) component / (B) component = 50/50 to 90/10,
The surfactant content is less than 1% by mass,
Der pH is 5.0 or less at 25 ° C. of diluted solution diluted to 2 wt% with pure water is,
Detergent composition characterized in Rukoto used at a dilution of 0.1 to 20.0 wt% with pure water.   The cleaning composition according to claim 1, wherein the component (A) is 1-hydroxyethane-1,1-diphosphonic acid and / or a salt thereof.   The said (B) component is glycolic acid and / or its salt, The cleaning composition of Claim 1 or 2 characterized by the above-mentioned.   A method for cleaning a glass hard disk substrate, comprising using the cleaning composition according to any one of claims 1 to 3 diluted with pure water to 0.1 to 20.0 mass%.