JPWO2012161270A1 - Cleaning agent and glass substrate cleaning method - Google Patents

Abstract

Without impairing the flatness of the glass substrate polished with the cerium oxide-containing abrasive, the abrasive grains remaining on and adhered to the surface are dispersed and removed. (A) Organic phosphonic acid, (B) polycarboxylate, (C) aromatic sulfonic acid, and (D) amine-alkylene oxide for cleaning a glass substrate polished with a cerium oxide-containing abrasive An aqueous cleaning agent containing an adduct. The glass substrate cleaning method includes a polishing step of polishing the glass substrate with a polishing agent containing cerium oxide, and a cleaning step of cleaning the glass substrate after the polishing step with the cleaning agent.

Description

  The present invention relates to a cleaning agent for cleaning a glass substrate polished with a cerium oxide-containing polishing agent, and a method for cleaning a glass substrate.

  For example, a glass substrate used for an FPD (Flat Panel Display) such as a liquid crystal display (LCD) is a glass substrate obtained by forming a molten glass into a plate shape by a manufacturing method called a float method and cutting the glass substrate. Polishing with a rotating and revolving polishing tool to remove minute irregularities and undulations on the surface, thereby obtaining a predetermined thickness that satisfies the flatness required for a glass substrate for FPD (for example, 0.4 to 1. 1 mm) (see, for example, Patent Document 1).

  In order to polish such a glass substrate, polishing abrasive grains containing cerium oxide as a main component and containing a rare earth element such as lanthanum are used. However, a glass substrate that requires high flatness such as an FPD glass substrate. In this case, the remaining abrasive on the substrate surface is a problem. For this reason, after polishing, the polishing agent (abrasive grains) adhering to the glass substrate surface is washed and removed (see, for example, Patent Document 2).

  For cleaning and removal of normal abrasives, cleaning agents containing alkali components are used, but for abrasives containing abrasive grains mainly composed of cerium oxide, The detergency was insufficient. In addition, in order to improve the cleaning / removability of abrasive grains mainly composed of cerium oxide, a cleaning agent containing an inorganic or organic alkali component and a surfactant is also used. Abrasive grain residues could not be reduced sufficiently.

  Furthermore, in order to remove the residue of the abrasive grains on the glass substrate, it is considered to use a cleaning agent containing citric acid, which is one of organic acids, and dissolve cerium oxide. However, the cleaning agent using citric acid as the organic acid has good initial cleaning characteristics, but there is a problem that the abrasive residue in the drainage agglomerates with time, resulting in problems in wastewater treatment.

Japanese Unexamined Patent Publication No. 2007-190657 Japanese Unexamined Patent Publication No. 2009-215093

  The present invention has been made to solve the above-described problems, and for glass substrates that can disperse and remove the abrasive grains remaining and / or adhered to the surface thereof without impairing the flatness of the glass substrate. It aims at providing the cleaning agent and the cleaning method of a glass substrate.

  A first aspect of the present invention is a cleaning agent for cleaning a glass substrate polished with a cerium oxide-containing polishing agent, wherein (A) an organic phosphonic acid, (B) a polycarboxylate, and (C) A cleaning agent characterized by being an aqueous cleaning agent containing an aromatic sulfonic acid and (D) an amine-alkylene oxide adduct.

In the cleaning agent of the first aspect, the sum of the (A) organic phosphonic acid, the (B) polycarboxylic acid salt, the (C) aromatic sulfonic acid, and the (D) amine-alkylene oxide adduct The amount of the (A) organic phosphonic acid is 0.01 to 50% by mass, the amount of the (B) polycarboxylic acid salt is 0.01 to 10% by mass, and the amount of the (C) aromatic sulfonic acid is 0.01% by mass. It is preferable to contain 0.02-10 mass% of said (D) amine-alkylene oxide adduct.
The (A) organic phosphonic acid is preferably an organic compound having a structure in which a group represented by the formula: —P (═O) (OH) ₂ is bonded to a carbon atom.
Furthermore, the (D) amine-alkylene oxide adduct is preferably a propylene oxide-ethylene oxide adduct of alkylenediamine.
And (A) the organic phosphonic acid, the (B) polycarboxylate, the (C) aromatic sulfonic acid, the (D) amine-alkylene oxide adduct, and water, It is preferable to contain 55 to 98% by mass of water with respect to the total amount of each component of A) to (D) and water.
The term “to” indicating the numerical range described above is used to mean that the numerical values described before and after it are used as the lower limit value and the upper limit value. Used with meaning.

  A second aspect of the present invention is a method for cleaning a glass substrate, wherein a polishing step of polishing a glass substrate using an abrasive containing cerium oxide, and the glass substrate after the polishing step are combined with the first substrate. And a cleaning step of cleaning with the cleaning agent according to the aspect.

In the glass substrate cleaning method according to the second aspect, the abrasive preferably contains abrasive grains containing cerium oxide as a main component and a rare earth element.
In the cleaning step, the glass substrate can be preferably cleaned by a single wafer type.
Furthermore, it is preferable to clean the glass substrate after the polishing step with a diluted cleaning solution obtained by diluting the cleaning agent with water.
Furthermore, in the said washing | cleaning process, it can wash | clean preferably by scrubbing both surfaces of the said glass substrate conveyed continuously using a brush, spraying the said cleaning agent.

  According to the cleaning agent of the present invention, polishing abrasive grains made of cerium oxide or the like remaining on and adhered to the surface of the glass substrate polished with an abrasive containing cerium oxide are dispersed and removed without impairing the flatness of the glass substrate. can do.

  Further, according to the cleaning method of the present invention, the glass substrate after polishing with the abrasive containing cerium oxide is efficiently cleaned without impairing the flatness of the surface, and the surface is free of foreign substances such as abrasive grains. A glass substrate with very little residue can be provided.

It is a figure which shows one Embodiment of the washing | cleaning method of the glass substrate of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to a cleaning agent for cleaning a glass substrate used for an FPD such as an LCD and a cleaning method using the cleaning agent. The FPD glass substrate polished with the cerium oxide-containing polishing agent is cleaned to remove the residue of the polishing agent on the polished glass substrate, and the embodiment of the present invention is a cleaning for this cleaning. Agent and cleaning method. The present invention is not limited to these embodiments, and other embodiments may belong to the category of the present invention as long as they match the gist of the present invention.

  1st Embodiment of this invention is a cleaning agent of the glass substrate for FPD, (A) organic phosphonic acid, (B) polycarboxylate, (C) aromatic sulfonic acid, (D) amine -An aqueous detergent containing an alkylene oxide adduct.

  According to this cleaning agent, polishing abrasive grains made of cerium oxide or the like remaining on and / or attached to the surface of the polished glass substrate can be well dispersed and removed, thereby impairing the flatness of the glass substrate. Nor. In addition, the abrasive residue in the cleaning waste liquid does not aggregate over time, and the cleaning drainage can be processed well.

  In the glass substrate cleaning agent according to the first embodiment of the present invention, the organic phosphonic acid as component (A) acts as a chelating agent for cerium oxide, and remains and / or adheres to the surface of the glass substrate. It promotes the dispersion of abrasive grains composed of, etc., and peels off from the surface of the glass substrate to remove it.

In the present invention, the organic phosphonic acid as the component (A) has a structure in which a group represented by the formula: -P (= O) (OH) ₂ (hereinafter referred to as a phosphonic acid group) is bonded to a carbon atom. An organic compound. The number of phosphonic acid groups per molecule of organic phosphonic acid is preferably 2 or more, more preferably 2 to 8, and particularly preferably 2 to 4.

The organic phosphonic acid in the present invention includes a compound having a structure in which a hydrogen atom bonded to carbon of a hydrocarbon which may have a substituent is substituted with a phosphonic acid group, and a nitrogen atom of ammonia or amines A compound having a structure in which a hydrogen atom bonded to is substituted with a methylenephosphonic acid group represented by —CH ₂ —P (═O) (OH) ₂ is preferable.

In the organic phosphonic acid having the former structure, the hydrocarbon which may have a substituent is preferably an aliphatic hydrocarbon or a hydroxyl group-containing aliphatic hydrocarbon. In these aliphatic hydrocarbons, the number of carbon atoms is preferably 1-6, and the number of hydroxyl groups is preferably 2 or less. Specific examples of the organic phosphonic acid having this structure include methyl diphosphonic acid and 1-hydroxyethane-1,1-diphosphonic acid.
The organic phosphonic acid in the present invention, including the organic phosphonic acid having a structure having the following methylenephosphonic acid group, includes a compound having a structure in which a hydrogen atom bonded to carbon of a hydroxyl group-containing aliphatic hydrocarbon is substituted with a phosphonic acid group. Particularly preferred is 1-hydroxyethane-1,1-diphosphonic acid.

  As the organic phosphonic acid having the latter structure, a compound having a structure in which all hydrogen atoms bonded to nitrogen atoms of ammonia or aliphatic amines are substituted with methylenephosphonic acid groups is preferable. However, a part of hydrogen atoms bonded to amine nitrogen atoms may be substituted with an organic group such as an alkyl group. As the aliphatic amine, an alkylene diamine or a polyalkylene polyamine which is a multimer thereof is preferable. As for carbon number of alkylenediamine, 2-4 are preferable. 2-8 are preferable and, as for the number of the hydrogen atoms (hydrogen atom substituted by a methylene phosphonic acid group) couple | bonded with the nitrogen atom of these amines, 2-4 are more preferable.

  Specific examples of organic phosphonic acids having this structure include aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), hexamethylenediaminetetra (methylenephosphonic acid), propylenediaminetetra (methylenephosphonic acid), and diethylenetriamine. Penta (methylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid), tris (2-aminoethyl) aminehexa (methylenephosphonic acid), trans-1,2-cyclohexanediaminetetra (methylenephosphonic acid), glycol etherdiaminetetra (Methylene phosphonic acid), and tetraethylene pentamine hepta (methylene phosphonic acid).

The (B) component polycarboxylate and the (C) component aromatic sulfonic acid improve the dispersibility and / or removability of the abrasive grains by the (A) organic phosphonic acid, and polish the abrasive. It works to prevent the reattachment of grains. Examples of the polycarboxylic acid salt as component (B) include poly (meth) acrylates, salts of (meth) acrylic acid-maleic acid copolymers, and the like.
Here, the notation (meth) acrylic acid means both acrylic acid and methacrylic acid. The weight average molecular weight (hereinafter abbreviated as Mw) of the polycarboxylic acid is preferably in the range of 2,000 to 50,000 from the viewpoint of preventing reattachment of abrasive grains and low foaming properties. Mw is a value measured by gel permeation chromatography (hereinafter abbreviated as GPC).

  In the polycarboxylate, the counter ion forming the salt is not particularly limited, but alkali metal (for example, sodium and potassium) salts, ammonium salts, primary amines (for example, alkylamines such as methylamine, ethylamine, and butylamine). Salts, secondary amines (eg, dialkylamines such as dimethylamine, diethylamine and dibutylamine, and diethanolamine) salts, tertiary amines (eg, trialkylamines such as trimethylamine, triethylamine and tributylamine, triethanolamine, N-methyl) Diethanolamine 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] Octane (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) salts, and quaternary ammonium salts (eg, tetraalkylammonium) salts are preferred. From the viewpoint of preventing the reattachment of particles, among these, preferred are alkali metal (for example, sodium and potassium) salts, ammonium salts, primary amine salts, secondary amine salts, tertiary amine salts and quaternary ammonium. Particularly preferred are salts of alkali metals (for example, sodium and potassium) and ammonium salts.

  Examples of the aromatic sulfonic acid as component (C) include alkylbenzene sulfonic acid having 8 to 14 carbon atoms, petroleum sulfonate, toluene sulfonic acid, xylene sulfonic acid, and cumene sulfonic acid. In particular, the use of metaxylene sulfonic acid (2,4-dimethylbenzenesulfonic acid) is preferred.

  The amine-alkylene oxide adduct as the component (D) functions to promote the penetration of the (A) organic phosphonic acid into the interface between the abrasive grains and the glass substrate. In the present embodiment, the amine-alkylene oxide adduct is preferably a compound known as an alkylene oxide addition type nonionic surfactant. As the alkylene oxide, ethylene oxide (hereinafter also referred to as EO) and propylene oxide (hereinafter also referred to as PO) are preferable, and a compound having a structure in which only one of them is added may be added. It may be a compound having the above structure. In a compound in which both EO and PO are added, the EO unit (that is, oxyethylene group) and the PO unit (that is, oxypropylene group) may exist in a block form or in a random form. May be. The former is obtained by sequentially adding EO and PO separately to the amine, and the latter is obtained by adding a mixture of EO and PO to the amine. In the present invention, the PO-EO adduct refers to an adduct obtained by any of these addition methods.

  As amines to which alkylene oxide is added, amines having 2 to 8 hydrogen atoms bonded to nitrogen atoms and 1 to 4 amino groups are preferred. Moreover, 16 or less are preferable and, as for carbon number of amines, 10 or less are more preferable. Examples of such amines include aliphatic monoamines and polyamines, alicyclic monoamines and polyamines, and aromatic monoamines and polyamines. More specifically, alkyl monoamines, alkylene diamines and polyalkylene polyamines that are multimers thereof, alicyclic monoamines and polyamines having at least one amino group or aminoalkyl group bonded to an alicyclic ring, and amino groups bonded to an aromatic ring. An alicyclic monoamine or polyamine having at least one group or aminoalkyl group is preferred.

  The amine-alkylene oxide adduct as the component (D) is preferably at least partly an alkylenediamine PO-EO adduct. As alkylene diamine, C2-C4 alkylenediamine is preferable and ethylenediamine is especially preferable. Examples of the PO—EO adduct of ethylenediamine include a compound in which PO and EO are added to four hydrogen atoms bonded to the nitrogen atom of ethylenediamine. In addition, as the amine-alkylene oxide adduct as the component (D), it is also preferable to use an aromatic amine PO adduct together with the ethylenediamine PO-EO adduct. Examples of the PO adducts of aromatic amines include metaxylylenediamine PO adducts. (D) When the PO-EO adduct of ethylenediamine and the PO adduct of aromatic amine are used in combination as the amine-alkylene oxide adduct, the stability of the cleaning / removing ability of the cleaning agent is further improved.

(A) component, (B) component, (C) component, and (D) component (hereinafter referred to as (A) component to (D) component collectively) with respect to the whole of the cleaning agent of the present invention including water. May be referred to as “(A) to (D)”.) The content ratio of each component of (A) to (A) is the total amount of each component of (A) to (D) including water. 0.01 to 50% by weight of organic phosphonic acid, 0.01 to 10% by weight of (B) polycarboxylate, 0.01 to 50% by weight of aromatic sulfonic acid, (D) amine-alkylene The oxide adduct is preferably 0.02 to 10% by mass.
Moreover, the mass% of the total of (B) polycarboxylate and (C) aromatic sulfonic acid with respect to the total amount of (A) to (D) including water is 0.03 to 60 mass%. Is preferred.
(D) When an amine-alkylene oxide adduct is used in combination with an alkylenediamine PO-EO adduct and an aromatic amine PO adduct, 0.01 to 5% by mass of an alkylenediamine PO-EO adduct The PO group adduct of the aromatic amine is 0.01 to 5% by mass, and the total mass% of the total amount of (A) to (D) including water is 0.02 to 10% by mass. It is preferable.

  The cleaning agent of the present invention is an aqueous cleaning agent obtained by dissolving the components (A) to (D) in water. In the present invention, the water in the cleaning agent dissolves the above-mentioned (A) organic phosphonic acid, (B) polycarboxylic acid salt, (C) aromatic sulfonic acid, and (D) amine-alkylene oxide adduct. It is a solvent. As this water, deionized water, ultrapure water, charged ion water, hydrogen water, ozone water, or the like can be used. Since water has a function of controlling the fluidity of the cleaning agent of the present invention, the content thereof can be appropriately set according to the target cleaning characteristics such as the cleaning speed. In the cleaning agent containing the components (A) to (D) in the above range and containing water, the content ratio of water to the total amount of the components (A) to (D) and water is It can be set to 55-98 mass%. Hereinafter, the cleaning agent containing the components (A) to (D) and water in the above ranges is also referred to as “cleaning agent stock solution”.

  In the cleaning agent of the present invention, in addition to the components (A) to (D), other additives can be added to water. Examples of other additives include a dispersant, a water-soluble organic solvent, an antioxidant, a rust inhibitor, a pH adjuster, a buffer, an antifoaming agent, an antiseptic, and a hydrotrope.

  The cleaning agent of the present invention configured as described above cleans a glass substrate using a polishing agent containing abrasive grains mainly composed of cerium oxide, and a glass substrate after the polishing step. In the manufacturing method of the glass substrate including at least 2 process with a washing | cleaning process, it is used for a washing process. In actually using the cleaning agent of the present invention for cleaning, the cleaning agent stock solution is further diluted with water so that the content (concentration) of the cleaning agent stock solution is 0.5 to 2.5% by mass. Are preferably used. By diluting with water as described above, it is possible to satisfactorily remove the abrasive grains made of cerium oxide and the like that remain and adhere without roughening the surface of the glass substrate.

In the polishing step, the surface of the glass substrate is polished using a polishing pad and containing abrasive grains containing cerium oxide as a main component and rare earth elements, for example, abrasive grains having an average grain size of 0.5 to 3.0 μm. It can be set as the process grind | polished with an agent slurry. The above average particle diameter is a value obtained by measuring the abrasive grains by the air permeation method (Blaine method). Hereinafter, when the average particle diameter is expressed in the present specification, the value obtained by this measurement method. Say.
Here, the abrasive grains containing cerium oxide as a main component and containing a rare earth element include 45 mass% or more of cerium oxide in the entire abrasive grains, and 0% of a rare earth element compound (for example, rare earth element oxide). The thing containing the mass%-55 mass% is pointed out. Examples of rare earth elements include La, Pr, and Nd.

  The cleaning step can be performed by a method in which the cleaning agent of the present invention is brought into direct contact with the polished glass substrate and cleaning is performed in a single wafer mode. In the cleaning method of the present invention, for example, as shown in FIG. 1, the cleaning nozzles 4 are provided on both upper and lower surfaces of the glass substrate 3 that is continuously transported in the cleaning chamber 2 in the horizontal direction by a mechanism such as a transport roll 1. A method of scribing with the rotating brush 6 disposed on both sides while spraying the sprayed cleaning agent 5 is employed.

  Here, the temperature of the cleaning agent 5 is not particularly limited, and is used at room temperature (15 ° C.) to 95 ° C. If the temperature exceeds 95 ° C., water may be boiled, which is inconvenient in the washing operation and is not preferable. Moreover, as the rotating brush 6 for cleaning, for example, a plurality of cylindrical brushes made of a PVA (polyvinyl alcohol) sponge and having an outer diameter of 70 to 100 mm can be used. In this case, for example, these brushes are arranged such that the rotation axis is perpendicular to the surface to be cleaned of the glass substrate 3 and the tip part is in contact with the surface to be cleaned of the glass substrate 3 or less than 2 mm. Arrange them at intervals. The rotational speed of the rotary brush 6 is preferably 100 to 500 rpm.

  As the cleaning agent 5, a diluted cleaning solution obtained by diluting the above-described cleaning agent stock solution of the present invention with water so as to have a desired concentration can be used. The injection amount can be 15 to 40 liters / minute.

  EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. In the following examples, “%” means mass% unless otherwise specified.

<Preliminary test 1 for detergency of cerium oxide>
First, a test piece was prepared. That is, a known polishing cerium oxide (CeO ₂ ) on one side of a glass substrate (product name: AN100; manufactured by Asahi Glass Co., Ltd., hereinafter the same) having a length of 5.0 cm × width of 4.0 cm × thickness of 0.07 cm. A 4% by mass aqueous solution of particles (average particle size 0.8 to 1.0 μm) was added dropwise and dried at room temperature for 20 minutes. Thus, as a test piece, a glass substrate (hereinafter, referred to as a particle-attached glass substrate) having white cerium oxide (CeO ₂ ) particles attached on one side was produced.

Next, an acid aqueous solution containing the organic acid shown in Table 1 at a concentration of 1% by mass was prepared. And the above-mentioned particle adhesion glass substrate was immersed in this aqueous solution at room temperature for 1 hour. And the surface state of the glass substrate after immersion was observed with the naked eye, and the detergency was evaluated according to the following criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
○: The cerium oxide particles are completely removed from the glass substrate surface.
Δ: Some cerium oxide particles remain on the glass substrate surface.
X: Residue of cerium oxide particles is observed.

  From the results of Table 1, it can be seen that when 1-hydroxyethane-1,1-diphosphonic acid is used as the organic acid, the cerium oxide has a high detergency and the cerium oxide particles on the surface of the glass substrate are well removed. It was.

<Preliminary test 2 for cleaning performance of cerium oxide>
A 4% by mass aqueous solution of known polishing cerium oxide (CeO ₂ ) particles (average particle size 0.8 to 1.0 μm) is dropped on one side of the same glass substrate (trade name: AN100), and the mixture is kept at room temperature for 60 minutes. It was made to dry and the cerium oxide particle adhesion glass substrate was produced.

Next, after preparing an aqueous solution containing compounds such as various surfactants, which are considered to improve the dispersibility of the cerium oxide particles, shown in Table 2 at a ratio (concentration) of 1% by mass, The cerium oxide particle-attached glass substrate was immersed at room temperature for 20 hours. And the surface state of the glass substrate after immersion was observed with the naked eye, and the dispersibility of the cerium oxide particles was evaluated according to the following criteria. The evaluation results are shown in Table 2. In addition, the used compound is a compound marketed as surfactant.
(Evaluation criteria)
○: The cerium oxide particles on the surface of the glass substrate are dispersed in the surfactant aqueous solution and completely removed.
Δ: Both dispersion and / or removal of the cerium oxide particles in the surfactant aqueous solution are insufficient. The cerium oxide particles are agglomerated and precipitated in the aqueous solution.
X: Almost no dispersion and / or removal of the cerium oxide particles in the surfactant aqueous solution is observed.

  From the results in Table 2, the following was confirmed. That is, from the viewpoint of dispersibility of the cerium oxide particles, it was found preferable to use a PO-EO adduct of polycarboxylate, metaxylenesulfonic acid and ethylenediamine. Moreover, it turned out that the PO adduct of metaxylylenediamine can also be used.

(Examples 1 and 2 and Comparative Examples 1 to 5)
A known polishing cerium oxide (CeO ₂ ) particle (average particle size: 0.8 to 1.0 μm) on one side of a glass substrate (trade name: AN100) having a length of 5.0 cm × width of 4.0 cm × thickness of 0.07 cm. ) Was added dropwise and dried at 50 ° C. for 30 minutes. In this way, a glass substrate having white cerium oxide (CeO ₂ ) particles attached to the surface was produced.

Moreover, as Example 1, 2, and Comparative Examples 1-5, each component shown in Table 3 was mix | blended with the composition shown in the same table, and the cleaning agent stock solution was prepared. Next, the cleaning property of the cleaning agent stock solution thus obtained was examined as follows. That is, after the obtained cleaning agent stock solution (including water) was diluted by adding water so that the concentration became 2% by mass, the above-mentioned particle-attached glass substrate was immersed in this cleaning dilution solution at room temperature for 9 hours. did. And the surface state of the glass substrate after immersion was observed with the naked eye, and the detergency was evaluated according to the following criteria. The evaluation results are shown in Table 3.
(Evaluation criteria)
○: The cerium oxide particles on the glass substrate surface are completely removed.
Δ: Some cerium oxide particles remain on the glass substrate surface.
X: The cerium oxide particle is hardly removed and remains on the glass substrate surface.

  From Table 3, 1-hydroxyethane-1,1-diphosphonic acid as component (A), polycarboxylic acid salt as component (B), metaxylenesulfonic acid as component (C), and component (D) When the diluted stock solutions of Examples 1 and 2 (further including a metaxylylenediamine PO adduct) containing the ethylenediamine PO-EO adduct were used, the cerium oxide on the glass substrate surface was used. It was found that the particles were well removed.

(Examples 3 and 4 and Comparative Example 6)
The glass substrate after the polishing step was cleaned by the method shown in FIG. As a cleaning agent, in Example 3, the concentration of the stock solution (concentration of the stock solution containing water) of the cleaning agent stock solution obtained in Example 1 (hereinafter referred to as organic acid system 1) is 0.5% by mass. In Example 4, the detergent stock solution obtained in Example 2 (hereinafter referred to as “organic acid system 2”) was used as the concentration of the stock solution (the concentration of the stock solution containing water). A diluted washing solution diluted with water so as to be 0.5% by mass was used. Further, in Comparative Example 6, cleaning was performed in the same manner using a diluted cleaning solution obtained by diluting a conventional alkaline cleaning agent with water so that the concentration became 0.1% by mass. The alkaline detergent is a detergent comprising potassium hydroxide and sodium hydroxide as inorganic alkali, ethylenediaminetetraacetate as a chelating agent, and polyoxyethylene dodecyl ether as a surfactant, and the balance water.

  As the glass substrate, AN100 (trade name) is used, and the polishing step is polishing with the surface of the glass substrate as a main component of known cerium oxide particles having an average particle size of 0.8 to 1.0 μm as an abrasive. A polishing slurry containing abrasive grains (trade name SHOROX A10; manufactured by Showa Denko KK) was used, and the polishing was performed using a polishing pad. In the cleaning step, the various diluted cleaning solutions described above are sprayed on the surface of the polished glass substrate at a rate of 250 to 700 mL per second, and a PVA brush rotating at a speed of 100 to 500 rpm for 6 to 10 seconds. Scrub.

  After cleaning in this manner, the amount of Ce and La remaining on the surfaces of the glass substrates cleaned in Example 3 and Example 4 and the glass substrate cleaned in Comparative Example 6 were analyzed by mass spectrometry using inductively coupled plasma emission method. (Abbreviation ICP-MS). Table 4 shows the measurement results.

  From Table 4, cleaning was performed using a diluted cleaning solution obtained by diluting the organic acid system 1 and the organic acid system 2 as the cleaning agent stock solutions obtained in Example 1 and Example 2 with water to a concentration of 0.5%. In Examples 3 and 4, it was found that there was very little Ce residue on the surface of the glass substrate and very little La residue compared to Comparative Example 6 using an alkaline cleaner. It was.

Examples 5 to 8, Comparative Examples 7 and 8
In Examples 5 to 8, as shown in Table 5, the diluted cleaning solution in which the organic acid system 1 or the organic acid system 2 was diluted with water to the concentration shown in the same table was used, and the polishing process was performed by the method shown in FIG. The glass substrate was cleaned. In Comparative Examples 7 and 8, a conventional alkaline cleaning agent diluted to the concentration shown in Table 5 was used, and cleaning was performed in the same manner. The alkaline cleaning agent is the same cleaning agent used in Comparative Example 6.

  As a glass substrate, AN100 (trade name) is used, and in the polishing step, the surface of the glass substrate is used as a main component with known cerium oxide particles for polishing having an average particle size of 0.8 to 1.0 μm as an abrasive. A polishing slurry (trade name SHOROX A10) containing polishing abrasive grains to be used was used, and a polishing pad was used. In the cleaning step, scrubbing was performed with a PVA brush rotating at a speed of 100 to 500 rpm for 6 to 10 seconds while spraying the diluted cleaning liquid on the surface of the polished glass substrate at a rate of 250 to 700 mL per second.

  After cleaning in this way, the number of particles (particles) such as abrasive grains remaining on the surface of the glass substrate was measured separately for each particle slice level. The slice level is one of the classification methods. The particle size is classified based on the intensity of the scattered light by irradiating the particles with laser light. The measurement was performed by a laser scattering imaging method (HS830E; manufactured by Toray Engineering Co., Ltd.). Table 5 shows the measurement results.

  From Table 5, the organic acid system 1 and the organic acid system 2, which are the detergent stock solutions obtained in Example 1 and Example 2, were 0.5% by mass, 2.0% by mass, and 2.5% by mass with water. In Examples 5 to 8 where cleaning was performed using a diluted cleaning solution diluted to a concentration, particles (particles) residue on the surface of the glass substrate compared to Comparative Examples 7 and 8 using an alkaline cleaning agent. In particular, it was found that the residual of fine particles of abrasive grains having a size (slice level) of about 0.3 μm was extremely small.

The cleaning agent of the present invention can be used for FPD because it can disperse and remove abrasive grains made of cerium oxide or the like remaining or adhered to the surface without impairing the flatness of the polished glass substrate. It can be effectively applied to a glass substrate cleaning method.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2011-115353 filed on May 24, 2011 are incorporated herein as the disclosure of the present invention. .

  DESCRIPTION OF SYMBOLS 1 ... Conveyance roll, 2 ... Cleaning chamber, 3 ... Glass substrate, 4 ... Cleaning nozzle, 5 ... Cleaning agent, 6 ... Rotating brush.

Claims (10)

A cleaning agent for cleaning a glass substrate polished with a cerium oxide-containing abrasive,
A cleaning agent characterized by being an aqueous cleaning agent comprising (A) an organic phosphonic acid, (B) a polycarboxylic acid salt, (C) an aromatic sulfonic acid, and (D) an amine-alkylene oxide adduct. .   The (A) organic phosphonic acid, the (B) polycarboxylic acid salt, the (C) aromatic sulfonic acid and the total amount of the (D) amine-alkylene oxide adduct, 0.01-50 mass% of phosphonic acid, 0.01-10 mass% of said (B) polycarboxylate, 0.01-50 mass% of said (C) aromatic sulfonic acid, said (D) amine The cleaning agent according to claim 1, comprising 0.02 to 10% by mass of an alkylene oxide adduct. The cleaning agent according to claim 1 or 2, wherein the (A) organic phosphonic acid is an organic compound having a structure in which a group represented by the formula: -P (= O) (OH) ₂ is bonded to a carbon atom.   The cleaning agent according to claim 1, wherein the (D) amine-alkylene oxide adduct is a propylene oxide-ethylene oxide adduct of alkylenediamine.   The (A) organic phosphonic acid, the (B) polycarboxylate, the (C) aromatic sulfonic acid, the (D) amine-alkylene oxide adduct, and water, The cleaning agent of any one of Claims 1-4 which contains 55-98 mass% of water with respect to the total amount of each component and water of (D). A polishing step of polishing a glass substrate with an abrasive containing cerium oxide;
A glass substrate cleaning method comprising a cleaning step of cleaning the glass substrate after the polishing step with the cleaning agent according to any one of claims 1 to 5.   The method for cleaning a glass substrate according to claim 6, wherein the abrasive contains abrasive grains containing cerium oxide as a main component and a rare earth element.   The method for cleaning a glass substrate according to claim 6 or 7, wherein in the cleaning step, the glass substrate is cleaned in a single wafer mode.   The glass substrate cleaning method according to any one of claims 6 to 8, wherein the glass substrate after the polishing step is cleaned with a diluted cleaning solution obtained by diluting the cleaning agent with water.   In the said washing | cleaning process, scrubbing both surfaces of the said glass substrate conveyed continuously using a brush, spraying the said washing | cleaning agent or the said diluted washing | cleaning liquid. A method for cleaning a glass substrate as described.

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