JP5321168B2 - Cleaning method for polished quartz glass substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning a quartz substrate used for photomasks, etc. in which silica and ceria remaining on the surfaces are efficiently removed with a washing liquid after polishing them with silica and ceria and in which a cleaning carrier made of stainless steel is less corroded. <P>SOLUTION: A polished quartz glass substrate is cleaned by being immersed in a washing liquid, or an aqueous solution, comprising a fluorine compound and phosphonic acid of which pH is 2-5, in which the zeta potential of the silica is -30 mV or more and -20 mV or less, in which the zeta potential of the ceria is -20 mV or more and -10 mV or less, and in which the etching rate of the quartz glass at room temperature is 0.3-3.0 nm/min. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a polished quartz glass substrate used for a photomask substrate or a high-temperature polysilicon liquid crystal substrate used in an exposure apparatus for forming a flat panel display or a semiconductor circuit pattern.

  In recent years, flat panel displays such as liquid crystals have been simultaneously increased in size and definition, so that photomasks necessary for the production of flat panel displays have become larger, and a reduction in defect density has been demanded. In the manufacture of semiconductor elements, reduced exposure is performed from a photomask to a semiconductor substrate. However, the pattern width to be formed is becoming narrower year by year, and it is an essential requirement to reduce the defect density of the photomask.

  In order to reduce the defect density of a polished quartz glass substrate used for a photomask substrate, etc., it is important to clean the quartz substrate after polishing. As a conventional chemical solution, abrasive particles with hydrofluoric acid, mixed acid such as sulfuric acid and nitric acid are used. And the like (for example, refer to Patent Document 1), and after the treatment with a low-concentration hydrofluoric acid aqueous solution, a method for performing a cleaning process using an alkali (for example, refer to Patent Document 2).

  It has also been proposed to use a cleaning agent containing a chelating agent in order to further reduce particles present on the surface of the polished quartz substrate (see, for example, Patent Document 3).

  However, the above-described cleaning method still does not sufficiently reduce the surface particle amount of the polished quartz substrate, and the quartz glass substrate is held in an etching tank of a multi-tank cleaning machine using a cleaning carrier for immersing the substrate. When the stainless steel cleaning carrier was immersed, the stainless steel was corroded and the etching solution was contaminated.

JP 2000-140778 A JP 2003-195471 A JP 11-340182 A

  An object of the present invention is to remove particles remaining on the surface of a silica or ceria substrate used for polishing a quartz glass substrate from the substrate surface, and to polish the chemical solution used for the removal with little risk of corroding the stainless steel cleaning carrier. An object of the present invention is to provide a method for cleaning a quartz glass substrate.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a cleaning solution comprising an aqueous solution comprising a fluorine compound having a specific pH, a zeta potential of silica and ceria, and an etching rate of quartz glass and phosphonic acid. It has been found that the particles present on the surface of the polished quartz glass substrate can be easily reduced by immersing in and cleaning the substrate, and the present invention has been completed.

  Aspects of the present invention are as follows.

  (1) pH is 2 to 5, silica zeta potential is -30 mV to -20 mV, ceria zeta potential is -20 mV to -10 mV, quartz glass etching rate at room temperature is 0.3 to 3.0 nm / min. A method for cleaning a polished quartz glass substrate, which comprises immersing and cleaning the polished quartz glass substrate in a cleaning solution comprising an aqueous solution containing a fluorine compound and phosphonic acid.

  (2) The method for cleaning a polished quartz glass substrate according to (1), wherein the cleaning solution has an oxidation-reduction potential of 450 mV to 600 mV.

  (3) In (1) or (2), the fluorine compound in the cleaning liquid is one or more of hydrofluoric acid, ammonium fluoride, silicofluoric acid, and fluoroboric acid. A method for cleaning a polished quartz glass substrate as described.

  (4) The phosphonic acid in the cleaning solution is one or two of hydroxyethylidene diphosphonic acid, nitrilotris (methylenephosphonic acid), aminotrimethylenephosphonic acid, phosphonobutanetricarboxylic acid, and ethylenediaminetetra (methylenephosphonic acid) The method for cleaning a polished quartz glass substrate according to any one of (1) to (3), which is described above.

  (5) The method for cleaning a polished quartz glass substrate according to any one of (1) to (4), wherein the pH of the cleaning liquid is adjusted with ammonia.

  (6) The method for cleaning a polished quartz glass substrate according to any one of (1) to (5), wherein the cleaning carrier for immersing the substrate is made of stainless steel.

  (7) The method for cleaning a polished quartz glass substrate according to any one of (1) to (6), wherein the quartz glass substrate is ultrasonically cleaned in advance with an alkaline detergent.

  (8) pH is 2 to 5, silica zeta potential is -30 mV to -20 mV, ceria zeta potential is -20 mV to -10 mV, quartz glass etching rate at room temperature is 0.3 to 3.0 nm / min. The quartz glass substrate is dipped and washed in a cleaning solution comprising an aqueous solution containing a fluorine compound and phosphonic acid, and the quartz glass substrate is further washed with a weak alkaline detergent (1) A method for cleaning a polished quartz glass substrate according to any one of to (6).

  (9) 0.1 to 0.5 wt% as fluorine in the fluorine compound and 0.2 to 3 phosphonic acid used in the method for cleaning a polished quartz glass substrate according to any one of (1) to (8) A cleaning solution comprising an aqueous solution containing 0.0 wt%.

  (10) The cleaning liquid according to (9), wherein the fluorine compound is ammonium fluoride and the phosphonic acid is hydroxyethylidene diphosphonic acid.

  Hereinafter, the present invention will be described in detail.

  The present invention has a pH of 2 to 5, a silica zeta potential of -30 mV to -20 mV, a ceria zeta potential of -20 mV to -10 mV, and an etching rate of quartz glass at room temperature of 0.3 to 3.0 nm / A method for cleaning a polished quartz glass substrate, which comprises immersing and cleaning the polished quartz glass substrate in a cleaning liquid comprising an aqueous solution containing a fluorine compound and phosphonic acid.

  The cleaning liquid used in the present invention comprises an aqueous solution containing a fluorine compound and phosphonic acid.

  As an example of the fluorine compound, one or more of hydrofluoric acid, ammonium fluoride, hydrosilicofluoric acid, and fluoroboric acid are preferable, and ammonium fluoride is particularly preferable.

  Examples of phosphonic acid are one or more of hydroxyethylidene diphosphonic acid, nitrilotris (methylenephosphonic acid), aminotrimethylenephosphonic acid, phosphonobutanetricarboxylic acid, ethylenediaminetetra (methylenephosphonic acid) Is preferred, and hydroxyethylidene diphosphonic acid is particularly preferred.

  The composition of the fluorine compound and phosphonic acid is not particularly limited as long as the pH, the zeta potential, and the etching rate of the quartz glass are within the above ranges, but the fluorine in the fluorine compound in the cleaning liquid is 0.1 to 0. It is preferable that they are 5 wt% and phosphonic acid 0.2-3.0 wt%.

  This is because if the concentration of the fluorine compound is too low, the etching proceeds slowly, so that the ability to remove the abrasive is reduced, and if it is too high, the surface may be roughened by the etching.

  Further, if the phosphonic acid concentration is too low, the negative shift effect of the zeta potential due to the negatively charged phosphonic acid is small, and if it is too high, the pH decreases and the zeta potential approaches zero and the reverse effect is obtained.

  The pH of the cleaning liquid used in the present invention is 2 to 5, more preferably 2.5 to 4. If the pH is less than 2, the zeta potential of the silica or ceria abrasive remaining on the substrate surface approaches zero, making it difficult to remove the abrasive from the quartz glass substrate. On the other hand, if the pH is higher than 5, the etching of the quartz glass substrate proceeds slowly, so that the removal ability of the abrasive is lowered.

  In the cleaning liquid used in the present invention, the zeta potential of silica is −30 mV to −20 mV and the zeta potential of ceria is −20 mV to −10 mV. The zeta potential represents the potential due to the fine particles dispersed in the liquid or the surface of the substance in the liquid. The same substance aggregates when the zeta potential approaches zero, and different substances tend to combine when the zeta potential approaches zero or the sign is opposite, so that foreign matter removal becomes difficult.

  The zeta potential usually tends to shift to minus as the pH increases depending on the pH, but the zeta potential can be changed by the additive even at the same pH. The present inventors have found that by adding phosphonic acid to a fluorine compound, the zeta potential of silica or ceria used for polishing a quartz glass substrate is shifted to minus.

  In the conventional cleaning method, the cleaning solution contained only about 0.01 wt% of phosphonic acid as a chelating agent, so that the zeta potential of silica or ceria used for polishing a quartz glass substrate was higher than that of the present invention. It was thought that it was not suitable for removing silica and ceria.

  However, in the present invention, by adding a large amount of phosphonic acid to the cleaning solution, the zeta potential of silica and ceria is reduced to a value at which silica and ceria are less likely to aggregate, so that silica and ceria can be easily removed.

  The zeta potential referred to in the present invention is a value obtained when measured by an electroacoustic method. In the electroacoustic method, a zeta potential can be obtained from a pressure amplitude value of a wave generated by supplying a high-frequency alternating electric field between electrodes and vibrating particles.

  Since the zeta potential varies somewhat depending on the size and concentration of the particles, the measurement sample in the present invention comprises submicron (preferably 0.2 to 0.8 μm) silica or ceria particles containing a fluorine compound and phosphonic acid. It was prepared by dispersing 1 (± 0.1) vol% in an aqueous solution. The zeta potential was measured at room temperature (25 ± 3 ° C.).

  The cleaning liquid used in the present invention is for etching a quartz glass substrate, and the etching rate suitable for cleaning needs to be 0.3 to 3.0 nm / min. This is because the residue of the polishing agent on the substrate is not sufficiently peeled at less than 0.3 nm / min, and the surface of the quartz glass substrate is likely to be roughened at more than 3.0 nm / min.

  The etching rate referred to in the present invention can be calculated by, for example, immersing a quartz glass substrate in an aqueous solution at room temperature and measuring the time required to reach a specific etching depth.

  Furthermore, the oxidation-reduction potential of the cleaning liquid used in the present invention is preferably 450 mV to 600 mV. This is because cleaning can be performed while corrosion of stainless steel is suppressed by setting the oxidation-reduction potential to 600 mV or less while securing the etching property of the quartz glass substrate by setting the oxidation-reduction potential to 450 mV or more.

  The pH of the cleaning solution used in the present invention can be adjusted by the concentration of the fluorine compound and phosphonic acid, but is preferably adjusted by adding ammonia.

  In addition, it is preferable that the temperature of the washing | cleaning liquid used by this invention shall be 10-30 degreeC.

  As a specific cleaning method for the polished quartz glass substrate of the present invention, the quartz glass substrate is polished using ceria or / and silica, and then immersed in a cleaning solution composed of the above-described aqueous solution of a fluorine compound and phosphonic acid. Thereafter, drying may be mentioned. Here, the rinsing liquid is preferably ultrapure water or functional water (for example, hydrogen water obtained by adding about 1 ppm of hydrogen and several ppm or less of ammonia to deaerated ultrapure water).

  Further, as a more preferable example, there is a method in which a quartz glass substrate is polished and then ultrasonically cleaned with an alkaline detergent, rinsed, washed in a cleaning solution composed of the above-described fluorine compound and phosphonic acid aqueous solution, rinsed, and dried in this order. Can be mentioned. As an alkaline detergent, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia, etc. are added to a nonionic or anionic surfactant to adjust the pH to 8-13. The thing which was done is mentioned. These are stronger as the pH is higher, but care must be taken because the surface of the polished quartz glass substrate tends to be rough.

  In order to rinse the alkali more strongly from the quartz glass substrate, it is preferable to apply ultrasonic waves in the rinsing step after ultrasonic cleaning with an alkaline detergent. Moreover, it is preferable to perform the rinse after immersion in the washing | cleaning liquid which consists of the aqueous solution of the above-mentioned fluorine compound and phosphonic acid, applying an ultrasonic wave which does not apply an ultrasonic wave or the level which dust generation by an ultrasonic wave can be disregarded.

  As another preferred example, after a quartz glass substrate is polished, it is immersed in a cleaning solution composed of the above-mentioned fluorine compound and phosphonic acid aqueous solution, rinsed, washed with a weak alkaline detergent in the order of ultrasonic cleaning, rinsing, and drying. Is mentioned. Here, as an alkaline detergent, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia or the like is added to a nonionic or anionic surfactant to adjust the pH to 8 to 8. What was adjusted to 10 is mentioned. It is preferable to set the pH within this range so that there is no residue of alkali components such as sodium and potassium after washing.

  Also, in order to rinse the alkali more strongly from the quartz glass substrate, it is preferable to apply ultrasonic waves in the rinsing process after ultrasonic cleaning with a weak alkaline detergent, but since it is close to the final stage, generation of ultrasonic dust is ignored. It is preferable to carry out while applying a possible level of ultrasonic waves.

  Further, after the quartz glass substrate is polished, preliminary cleaning such as scrub cleaning and hot concentrated sulfuric acid cleaning may be performed, and then cleaning may be performed by the above method.

  According to the present invention, it is possible to reduce the surface particles of the polished quartz substrate. Also, corrosion of the stainless steel cleaning carrier is reduced.

  Examples are shown below, but the present invention is not limited to these Examples.

The zeta potential was measured using a dense zeta potential measuring instrument (manufactured by Matec Applied Sciences, trade name “ESA-9800”) and silica powder having an average particle size of 0.3 μm (trade name, manufactured by Admatechs). “SO-E1”) or an electrode inserted into an aqueous solution in which 1 vol% of ceria powder having an average particle diameter of 0.6 μm (trade name “ESO-7” manufactured by Mitsui Mining & Smelting Co., Ltd.) is dispersed, and high-frequency alternating current is applied between the electrodes. Was obtained from the pressure amplitude value of the wave generated by vibrating the particles.
Electrode type: Gold-plated stainless steel electrodeFrequency: 1.1-1.2 MHz
Measurement temperature: 26-27 ° C
Example 1
The washing solution in the first tank of the multi-tank washing machine is a detergent that has sodium hydroxide added to an anionic surfactant to adjust the pH to 12. The washing liquid in the second tank is cold pure water, and the washing liquid in the third tank is flushed. An aqueous solution comprising ammonium fluoride 0.4 wt% and hydroxyethylidene diphosphonic acid 1.0 wt%, the fourth tank cleaning liquid was cold pure water, the fifth tank cleaning liquid was cold pure water, and the sixth tank cleaning liquid was warm pure water.

  Next, a quartz glass substrate (size 1220 × 1400 mm) polished with colloidal silica and a quartz glass substrate (size 1220 × 1400 mm) polished with ceria were prepared, and both were washed by the following procedure. First, scrub cleaning and shower rinse preliminary cleaning were performed. Next, the substrate was placed on a cleaning carrier made of stainless steel (SUS316), immersed in the first tank, and subjected to ultrasonic cleaning (frequency: 100 kHz, 4.8 kW) for 5 minutes. Next, the substrate is immersed in the second tank for 5 minutes by ultrasonic rinsing (frequency: 100 kHz, 4.8 kW), and then the substrate is transferred to the third tank and only when the quartz glass etching depth is 2.0 nm. Immersion, further transferred to the fourth tank, immersed for 10 minutes, transferred to the fifth tank, immersed for 10 minutes, immersed in the sixth tank for 5 minutes, and then the substrate was slowly pulled up and dried.

(Example 2)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.4 wt% ammonium fluoride and 0.5 wt% hydroxyethylidene diphosphonic acid, and the cleaning liquid in the other tanks is the same as in Example 1. The quartz glass substrate polished with the two types of abrasives was washed in the same procedure as described above.

(Example 3)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.4 wt% ammonium fluoride and 2.0 wt% hydroxyethylidene diphosphonic acid, and the cleaning liquid in the other tanks is the same as in Example 1. The quartz glass substrate polished with the two types of abrasives was washed in the same procedure as described above.

Example 4
The cleaning solution for the third tank of the multi-tank type washing machine is an aqueous solution comprising ammonium fluoride 0.4 wt%, hydroxyethylidene diphosphonic acid 1.0 wt%, and nitric acid 0.5 wt%. In the same manner, a quartz glass substrate polished with two types of abrasives was washed in the same procedure as in Example 1.

(Example 5)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.2 wt% ammonium fluoride and 1.0 wt% hydroxyethylidene diphosphonic acid, and the cleaning liquid in the other tanks is the same as in Example 1. The quartz glass substrate polished with the two types of abrasives was washed in the same procedure as described above.

(Example 6)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.7 wt% ammonium fluoride and 1.0 wt% hydroxyethylidene diphosphonic acid, and the cleaning liquid in the other tanks is the same as in Example 1. The quartz glass substrate polished with the two types of abrasives was washed in the same procedure as described above.

(Example 7)
The cleaning solution for the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.4 wt% of hydrosilicofluoric acid and 0.8 wt% of hydroxyethylidene diphosphonic acid, and the cleaning liquid of the other tanks is the same as in Example 1. A quartz glass substrate polished with two types of abrasives was washed in the same procedure as in Example 1.

(Example 8)
The cleaning solution in the third tank of the multi-tank cleaning machine is an aqueous solution comprising 0.4 wt% ammonium fluoride and 1.0 wt% nitrilotris (methylenephosphonic acid), and the cleaning liquid in the other tanks is the same as in Example 1. A quartz glass substrate polished with two types of abrasives was washed in the same procedure as in Example 1.

Example 9
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution of ammonium fluoride 0.4 wt%, hydroxyethylidene diphosphonic acid 2.0 wt%, and ammonia 0.2 wt%. In the same manner, a quartz glass substrate polished with two types of abrasives was washed in the same procedure as in Example 1.

(Comparative Example 1)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.4 wt% ammonium fluoride and 4.0 wt% hydroxyethylidene diphosphonic acid, and the cleaning liquid in the other tanks is the same as in Example 1. The quartz glass substrate polished with the two types of abrasives was washed in the same procedure as described above.

(Comparative Example 2)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution composed of 0.2 wt% hydrofluoric acid and 4.0 wt% nitric acid, and the cleaning liquid in the other tanks is the same as in Example 1 and is the same as in Example 1. The quartz glass substrate polished with two types of abrasives in the procedure was washed.

(Comparative Example 3)
The cleaning liquid in the third tank of the multi-tank cleaning machine is an aqueous solution of 0.2 wt% hydrofluoric acid, and the cleaning liquids in the other tanks are the same as in Example 1, and two types of polishing are performed in the same procedure as in Example 1. The quartz glass substrate polished with the agent was washed.

  Table 1 shows the pH of the third tank cleaning solution in Examples 1 to 9 and Comparative Examples 1 to 3, the zeta potential of silica, the zeta potential of ceria, the oxidation-reduction potential, the etching rate of quartz glass at room temperature, and the corrosion of stainless steel (SUS316). Indicates speed.

  The cleaning liquids in the third tanks of Examples 1 to 9 each have a pH of 2 to 5, a silica zeta potential of −30 mV to −20 mV, a ceria zeta potential of −20 mV to −10 mV, and quartz glass at room temperature. The etching rate is in the range of 0.3 to 3.0 nm / min. Further, the corrosion rate of SUS316 was less than half in Examples 1 to 9 compared to Comparative Examples 2 to 3, and corrosion was suppressed.

  Next, after polishing with an abrasive of colloidal silica and ceria, each quartz glass substrate washed by the procedure of Example 1 was placed on a laser type defect inspection apparatus, and the number of foreign substances adhered to the substrate of 1 μm or more was examined. The results are shown at the right end of Table 1. In any of the substrates, the number of foreign substances adhering to the substrate was small (within 10) in Examples 1 to 9 compared with Comparative Examples 1 to 3, which was favorable. These results are thought to be mainly due to the negative and large zeta potential of the abrasive.

（実施例１０）
多槽式洗浄機の第１槽の洗浄液をフッ化アンモニウム０．４ｗｔ％、ヒドロキシエチリデンジホスホン酸１．０ｗｔ％からなる水溶液、第２槽の洗浄液を冷純水、第３槽の洗浄液を非イオン系界面活性剤に炭酸ナトリウムを添加してｐＨを９とした洗剤、第４槽の洗浄液を超純水に水素を１ｐｐｍ、アンモニアを３ｐｐｍ以下添加した水素水、第５槽の洗浄液を冷純水、第６槽の洗浄液を温純水とした。

(Example 10)
The cleaning solution for the first tank of the multi-tank cleaning machine is an aqueous solution of 0.4 wt% ammonium fluoride and 1.0 wt% of hydroxyethylidene diphosphonic acid, the second cleaning liquid is cold pure water, and the third cleaning liquid is not used. Detergent with sodium carbonate added to ionic surfactant to pH 9; 4th tank cleaning liquid with ultrapure water with 1ppm hydrogen and 3ppm ammonia or less; 5th tank cleaning liquid with cold purity Water and the cleaning liquid in the sixth tank were warm pure water.

  Next, a quartz glass substrate (size 1220 × 1400 mm) polished with colloidal silica and a quartz glass substrate (size 1220 × 1400 mm) polished with ceria were prepared, and both were washed by the following procedure. First, scrub cleaning and shower rinse preliminary cleaning were performed. Next, the substrate is placed on a cleaning carrier made of stainless steel (SUS316) and immersed in the first tank for 2 minutes, then the substrate is immersed in the second tank and ultrasonic rinse (frequency 100 kHz, 4.8 kW), Thereafter, the substrate is transferred to the third tank and subjected to ultrasonic cleaning for 5 minutes (frequency 100 kHz, 4.8 kW), further transferred to the fourth tank for 10 minutes ultrasonic rinse (frequency 150 kHz, 2.4 kW), and transferred to the fifth tank. The substrate was immersed for 10 minutes and immersed in the sixth tank for 5 minutes, and then the substrate was slowly pulled up and dried.

  Each quartz glass substrate cleaned by the procedure of Example 10 was placed on a laser type defect inspection apparatus, and the number of foreign substances adhered to the substrate of 1 μm or more was examined. The quartz glass substrate polished with colloidal silica had 3 foreign substances adhered to the substrate, and the quartz glass substrate polished with ceria had 5 foreign substances adhered to the substrate, and good cleaning results were obtained even if the order of cleaning was changed.

  A photomask substrate or the like used in an exposure apparatus for forming a semiconductor circuit pattern in which the amount of surface particles is sufficiently reduced can be manufactured.

Claims (10)

The pH is 2 to 5, the zeta potential of silica is −30 mV to −20 mV, the zeta potential of ceria is −20 mV to −10 mV, and the etching rate of quartz glass at room temperature is 0.3 to 3.0 nm / min. It is characterized by immersing and cleaning the polished quartz glass substrate in a cleaning solution comprising an aqueous solution containing 0.1 to 0.5 wt% as fluorine in the fluorine compound and 0.2 to 3.0 wt% of phosphonic acid. A method for cleaning a polished quartz glass substrate. 2. The method for cleaning a polished quartz glass substrate according to claim 1, wherein the cleaning solution has an oxidation-reduction potential of 450 mV to 600 mV. 3. The polished quartz according to claim 1, wherein the fluorine compound in the cleaning liquid is one or more of hydrofluoric acid, ammonium fluoride, hydrosilicofluoric acid, and fluoroboric acid. A method for cleaning a glass substrate. The phosphonic acid in the cleaning solution is one or more of hydroxyethylidene diphosphonic acid, nitrilotris (methylenephosphonic acid), aminotrimethylenephosphonic acid, phosphonobutanetricarboxylic acid, and ethylenediaminetetra (methylenephosphonic acid). The method for cleaning a polished quartz glass substrate according to any one of claims 1 to 3. The method for cleaning a polished quartz glass substrate according to any one of claims 1 to 4, wherein the pH of the cleaning liquid is adjusted with ammonia. The method for cleaning a polished quartz glass substrate according to any one of claims 1 to 5, wherein a cleaning carrier for immersing the substrate is made of stainless steel. The method for cleaning a polished quartz glass substrate according to any one of claims 1 to 6, wherein the quartz glass substrate is ultrasonically cleaned in advance with an alkaline detergent. The pH is 2 to 5, the zeta potential of silica is −30 mV to −20 mV, the zeta potential of ceria is −20 mV to −10 mV, and the etching rate of quartz glass at room temperature is 0.3 to 3.0 nm / min. The polished quartz glass substrate is immersed in a cleaning solution composed of an aqueous solution containing 0.1 to 0.5 wt% as fluorine in the fluorine compound and 0.2 to 3.0 wt% of phosphonic acid , and then washed with quartz. The method for cleaning a polished quartz glass substrate according to any one of claims 1 to 6, wherein the glass substrate is further cleaned with a weak alkaline detergent. The fluorine in the fluorine compound used in the method for cleaning a polished quartz glass substrate according to any one of claims 1 to 8 includes 0.1 to 0.5 wt% and phosphonic acid 0.2 to 3.0 wt%. A cleaning solution comprising an aqueous solution. The cleaning liquid according to claim 9, wherein the fluorine compound is ammonium fluoride and the phosphonic acid is hydroxyethylidene diphosphonic acid.