JP3375052B2 - Cleaning water for electronic materials - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to cleaning water for electronic materials. More specifically, the present invention relates to cleaning water for electronic materials, which can be effectively cleaned at room temperature with a low concentration of a dissolved amount of a chemical in wet cleaning for removing impurities, particularly fine particles from the surface of electronic materials.

[0002]

2. Description of the Related Art Removing fine particles from the surface of electronic materials such as silicon substrates for semiconductors, glass substrates for liquid crystals, and quartz substrates for photomasks is extremely important for preventing product defects. For this purpose, so-called APM cleaning has been conventionally performed in which an aqueous solution of a mixture of ammonia and hydrogen peroxide is heated and used. The standard mixing ratio of chemicals used for APM cleaning is ammonia water (29% by weight): hydrogen peroxide solution (30% by weight): water = 1: 1: 5, and the cleaning temperature is around 80 ° C. It is a common method. While the APM cleaning method exhibits a very excellent effect of removing fine particles, it uses a large amount of high-purity chemicals, and therefore requires a large amount of ultrapure water for the rinse after cleaning, and the burden of wastewater treatment is heavy. That a heating and temperature adjustment mechanism is required, and that air conditioning equipment that discharges vapor to generate a large amount of chemical vapor and takes in fresh air in an amount equivalent to the exhaust volume for cleaning It has many problems. As a method for solving the above-mentioned problems without impairing the effect of removing fine particles, a chemical is diluted several times more than before, or the temperature is set to about 40 ° C or room temperature.
A method of using ultrasonic vibration in combination is being studied. Such an improvement is based on the conventional method and has an advantage that it can be easily adopted in a mass production factory, but the effect of improving the problem is small. Because of this, the amount of drug used is small,
There has been a demand for cleaning water for electronic materials that can be cleaned at room temperature and has a large cleaning effect.

[0003]

SUMMARY OF THE INVENTION According to the present invention, in wet cleaning for removing impurities, particularly fine particles from the surface of an electronic material, it is possible to effectively perform cleaning at room temperature with a low concentration of a dissolved drug. The purpose was to provide cleaning water for electronic materials, which has a great effect on resources and environmental protection and is easy to use in mass production plants.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that water containing ammonia and hydrogen peroxide in a low concentration has a concentration higher than the atmospheric saturation concentration. It was found that cleaning water obtained by dissolving oxygen gas has an excellent effect in removing fine particles adhering to the surface of the electronic material, and based on this finding, the present invention has been completed. That is, according to the present invention, (1) oxygen gas is dissolved at a concentration higher than the atmospheric saturation concentration, and the amount of ammonia is 0.1 to 10,0.
00 mg / liter and hydrogen peroxide 0.1-10,000 mg /
(1) The cleaning water for electronic materials, which contains liters, and (2) the electronic material that is the object to be cleaned is a silicon substrate for semiconductors, a glass substrate for liquid crystals, or a quartz substrate for photomasks (1) To provide cleaning water for electronic materials. Further, as a preferred embodiment of the present invention, (3) the washing water for electronic materials according to (1), wherein the dissolved oxygen gas concentration is 12 mg / liter or more, and (4) the dissolved oxygen gas concentration is 20 mg / liter or more. Cleaning water for electronic materials as described in (3), (5) Dissolved oxygen gas concentration is 30 mg /
The washing water for electronic materials according to the item (4), which is liter or more,
(6) Detergent of water to reduce the degree of saturation of the dissolved gas, and then oxygen gas is supplied to dissolve the oxygen gas in the water. (7) The method for producing washing water for electronic materials according to item (6), wherein the oxygen-saturated amount of supply of oxygen gas is substantially equivalent to the decrease in the degree of saturation of the degassed gas, (8) A method for producing cleaning water for electronic materials according to item (7), wherein a gas permeable membrane module is used to remove dissolved gas from water and dissolve oxygen gas,
(9) The gas permeable membrane module is provided in two stages, decompression membrane deaeration for all dissolved gas is performed using the gas permeable membrane module in the first stage, and oxygen gas is dissolved using the gas permeable membrane module in the second stage. A method for producing cleaning water for electronic materials according to item (8), and (10) cleaning water for electronic materials according to item (1) while ultrasonic waves having a frequency of 400 kHz or higher are transmitted. And a method for cleaning electronic materials, and
(11) The method for cleaning an electronic material according to the item (10), in which the cleaning water for electronic materials is used while being kept at room temperature.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The cleaning water for electronic materials of the present invention dissolves oxygen gas at a concentration higher than the atmospheric saturation concentration, and contains 0.1 to 10,000 mg / liter of ammonia and 0.1 to 10 hydrogen peroxide. It contains 1,000 mg / liter. The water used for the cleaning water for electronic materials of the present invention is preferably ultrapure water. Further, the ammonia and hydrogen peroxide solution used in the cleaning water for electronic materials of the present invention are preferably high-purity electronic material grade products. The atmospheric saturation concentration is the concentration of gas dissolved in water in equilibrium with the atmosphere. The atmospheric saturation concentration of oxygen gas varies depending on the temperature, is high at low temperatures and is low at high temperatures, but is about 8-9 mg / liter at 20-25 ° C. The washing water for electronic materials of the present invention preferably has a dissolved oxygen gas concentration of 12 mg / liter or more,
More preferably at least mg / liter, 30 mg /
More preferably, it is liter or more. The concentration of dissolved oxygen gas in the cleaning water for electronic materials of the present invention can be selected according to the purpose of use. The cleaning water for electronic materials of the present invention, which dissolves oxygen gas at a concentration higher than the atmospheric saturation concentration and contains low concentrations of ammonia and hydrogen peroxide, can be applied to all of metal contamination, organic contamination and particulate contamination on the surface of electronic materials. Although it has a removing effect, it exhibits an excellent effect especially for removing fine particle contamination. The cleaning water for electronic materials of the present invention,
It can be suitably used for cleaning silicon substrates for semiconductors, glass substrates for liquid crystals, quartz substrates for photomasks, and the like.

The method for producing the cleaning water for electronic materials of the present invention is not particularly limited, and ammonia and hydrogen peroxide can be added to water in which oxygen gas is dissolved in a concentration higher than the atmospheric saturation concentration in advance. Alternatively, it can be produced by dissolving oxygen gas in water containing ammonia and hydrogen peroxide at a concentration higher than the atmospheric saturation concentration. Among these methods, a method of adding ammonia and hydrogen peroxide to water in which oxygen gas is dissolved in advance is preferable. According to the method of dissolving oxygen gas before adding ammonia and hydrogen peroxide, degassing water prior to the dissolution of oxygen gas,
Even if the saturation level of the dissolved gas is reduced, there is no risk that ammonia will be transferred to the gas phase and lost, or that the concentration of oxygen gas in water will be reduced and hydrogen peroxide will be decomposed. Dissolving oxygen gas in water is preferably performed by degassing water to reduce the saturation of the dissolved gas, and then supplying oxygen gas to dissolve the oxygen gas in water. In the present invention, the degree of saturation of a gas is the amount of gas dissolved in water,
It is a value divided by the dissolved amount of gas at 0 ⁵ Pa and a temperature of 20 ° C. For example, when water is in equilibrium with nitrogen gas having a pressure of 10 ⁵ Pa and a temperature of 20 ° C., the amount of nitrogen gas dissolved in water is 19.2 mg / liter, so the gas dissolved in water is Nitrogen gas only, the dissolution amount is 1
The saturation of water, which is 9.2 mg / liter, is 1.0 times,
The gas dissolved in water is only nitrogen gas, and the amount of water dissolved therein is 9.6 mg / liter, and the degree of saturation of water is 0.5 times. Further, water in equilibrium in contact with air at a pressure of 10 ⁵ Pa and a temperature of 20 ° C. dissolves 15.4 mg / liter of nitrogen gas and 8.8 mg / liter of oxygen gas and has a saturation degree of 1.
Since the state is 0 times, the degree of saturation of water when the amount of dissolved gas is 1.5 mg / liter of nitrogen gas and 0.9 mg / liter of oxygen gas by degassing is 0.1 times. Furthermore, when water is in equilibrium with oxygen gas having a pressure of 10 ⁵ Pa and a temperature of 20 ° C., the amount of dissolved oxygen gas in water is 44.0 mg /
Since it is liter, the gas dissolved in water is only oxygen gas, and the degree of saturation of water whose dissolved amount is 22.0 mg / liter is 0.5 times.

In order to enhance the effect of the functional water for cleaning in the cleaning water for electronic materials of the present invention, it is desirable that the concentration of dissolved oxygen gas is higher, and the saturated concentration at room temperature under atmospheric pressure is about 44 mg / liter. The closer to, the greater the cleaning effect. However, even if the dissolved oxygen gas concentration is not increased to near saturation, if the concentration is at a certain level or higher, the cleaning water for electronic materials is substantially effective. Its concentration is 12 mg / liter or more, preferably about 20 mg / liter, that is, 1 of the saturation degree of the dissolved oxygen gas at room temperature and atmospheric pressure.
It has already been confirmed by the present inventors that it is less than / 2 times. When the dissolved oxygen gas concentration is increased to about 30 mg / liter, that is, about 70% of the saturation, a higher cleaning effect can be obtained. In the production of the cleaning water for electronic materials of the present invention, the degree of degassing of water is not particularly limited, but in order to efficiently produce the cleaning water for electronic materials having a dissolved oxygen gas concentration of 20 mg / liter or more, Degas the amount of dissolved gas that corresponds to the saturation of oxygen gas,
It is preferable to make room for the gas dissolution capacity in water. For example, in the case of dissolving oxygen gas having a saturation of ½ or more, it is preferable to remove the dissolved gas having a saturation of ½ or more in advance by degassing. By making the degassing amount of the dissolved gas of the raw water converted into the saturation degree and the amount of the oxygen gas to be dissolved converted into the saturation degree substantially equal to each other, the oxygen gas can be easily dissolved without waste.

In the water in equilibrium with the atmosphere in which the dissolved gas is not controlled, about 8 mg / liter of oxygen gas at room temperature,
About 16 mg / liter of nitrogen gas and a small amount of carbonic acid are dissolved. When this water is used as raw water, the concentration of dissolved nitrogen gas is about 8 mg / liter or less, that is, the saturation level of 1
If reduced to less than about 1/2, the oxygen gas will reach 1 /
It can be easily dissolved up to about 2 and it is possible to obtain washing water for electronic materials having a dissolved oxygen gas concentration of 20 mg / liter or more. In the method of the present invention, the raw water does not necessarily have to be in equilibrium with the atmosphere, and there are no restrictions on the type of dissolved gas, the concentration ratio, and the like. For example, if the dissolved gas is replaced by almost only nitrogen gas and the concentration of the dissolved nitrogen gas is increased, degassing the dissolved nitrogen gas from there will achieve the purpose. You can In short, the amount of reduction of the total dissolved gas is converted into the degree of saturation, and the amount may be more than the degree of saturation of the oxygen gas to be dissolved. The degassing treatment in the production of the cleaning water for electronic materials of the present invention is preferably vacuum degassing or depressurization membrane degassing, which can be removed regardless of the type of gas. Among these, the membrane degassing by the high-purity degassing membrane module is particularly preferable because it is possible to degas a minute amount of dissolved gas at a point relatively close to the point of use without impairing the purity of the raw water. Can be used.

In the present invention, the method of dissolving oxygen gas in water is not particularly limited. For example, a high concentration oxygen gas is brought into contact with water by bubbling without degassing the water, and based on Henry's law. It is possible to reduce the dissolved nitrogen gas in the water to a dissolved oxygen gas concentration of 30 mg / liter or more. According to the method of bubbling oxygen gas into water, the amount of oxygen gas required to increase the dissolved oxygen gas in water to a certain concentration is large, but it is possible to easily dissolve oxygen gas in high concentration without using a special device. Water containing oxygen gas can be produced. In producing water in which oxygen gas is dissolved by bubbling oxygen gas into water,
It is preferable to remove the dissolved gas from water in advance and then bubble oxygen gas. The method for removing the dissolved gas from water is not particularly limited, and for example, water can be passed through a degassing membrane device or can be passed through a packed column kept under reduced pressure. By bubbling oxygen gas after removing the dissolved gas from water, the amount of oxygen gas required to increase the dissolved oxygen gas in water to a certain concentration can be reduced. In the present invention, a gas permeable membrane module can also be used to increase the concentration of dissolved oxygen gas in water. For example, the dissolved oxygen gas concentration can be set to 30 mg / liter or more by ventilating the oxygen gas as a sweep gas into the gas phase of the gas permeable membrane module. Most dissolved gases other than oxygen gas in water that are in equilibrium with the atmosphere are nitrogen gas, so increase the partial pressure of oxygen gas in the gas phase of the gas permeable membrane module and replace it with nitrogen gas dissolved in water. By this, the dissolved nitrogen gas can be reduced and the dissolved oxygen gas concentration can be increased. According to the method of using the oxygen gas as the sweep gas, the oxygen gas in excess to some extent is required, but the dissolved oxygen gas concentration can be easily increased by using a simple device.

In the present invention, the gas permeable membrane module may be used in multiple stages to remove dissolved gas and dissolve oxygen gas. For example, a gas permeable membrane module is provided in two stages, decompression membrane deaeration for all dissolved gases is performed using the gas permeable membrane module in the previous stage, and oxygen gas is dissolved using the gas permeable membrane module in the subsequent stage. You can By installing the gas permeable membrane module in two stages and performing depressurization membrane degassing for all dissolved gases and dissolution of oxygen gas,
Oxygen gas can be dissolved in water almost quantitatively without wasting. When the gas permeable membrane module is provided in two stages and the depressurized membrane deaeration for all dissolved gas is performed using the gas permeable membrane module of the preceding stage, oxygen gas is allowed to exist in the depressurized gas phase of the gas permeable membrane module of the preceding stage. be able to. The presence of oxygen gas in the decompressed gas phase of the gas permeable membrane module in the preceding stage slightly increases the amount of oxygen gas used, but the nitrogen gas removal efficiency in the gas permeable membrane module in the preceding stage is improved, and at the same time water It can dissolve oxygen gas. In the present invention, a method for dissolving oxygen gas can be appropriately selected depending on the concentration of dissolved oxygen gas required, the amount of washing water for electronic materials used, and the like.

In the cleaning water for electronic materials of the present invention, the content of ammonia is 0.1 to 10,000 mg / liter, more preferably 1 to 100 mg / liter. Since the cleaning water for electronic materials contains ammonia, the cleaning water for electronic materials becomes alkaline, and the surface potentials of the particles and the object to be cleaned both become negative, so that the particles are prevented from reattaching to the surface of the object to be cleaned. be able to. If the ammonia content is less than 0.1 mg / liter, the cleaning effect may be insufficient. Ammonia content is 1
A sufficient cleaning effect is exhibited at less than 000 mg / liter, and it is not usually necessary to contain ammonia in excess of 10,000 mg / liter. If the ammonia content is too large, the water required for rinsing after cleaning is required. There is a possibility that the amount will increase. In the cleaning water for electronic materials of the present invention, the content of hydrogen peroxide is 0.1 to 10,000 mg / liter,
More preferably, it is 1 to 100 mg / liter. Since the cleaning water for electronic materials contains hydrogen peroxide, it is possible to more stably maintain the oxidizing property and prevent the surface of the object to be cleaned from being roughened, as compared with the case where only oxygen gas is dissolved. If the hydrogen peroxide content is less than 0.1 mg / liter, the cleaning effect may be insufficient. When the hydrogen peroxide content is 10,000 mg / liter or less, a sufficient cleaning effect is exhibited, and it is not usually necessary to contain hydrogen peroxide in excess of 10,000 mg / liter, and the hydrogen peroxide content is high. If too much, the amount of water required for the rinse after washing may increase.

The washing water for electronic materials of the present invention is
In particular, the method of contacting the electronic material contaminated with the fine particles is not particularly limited, and can be appropriately selected depending on the type of the fine particles, the particle size, the adhesion amount, and the like. For example, an electronic material contaminated with fine particles may be immersed in cleaning water for electronic materials to perform batch cleaning, or single-wafer cleaning in which one sheet is processed at a time may be performed. Examples of the single-wafer cleaning method include spin cleaning in which cleaning water for electronic materials is poured while rotating the electronic materials contaminated with fine particles. When cleaning the electronic material contaminated with fine particles by using the cleaning water for electronic materials of the present invention, ultrasonic vibration can be transmitted to the cleaning water for electronic materials. There is no particular limitation on the method of transmitting ultrasonic vibrations to the cleaning water for electronic materials, and for example, in batch cleaning, ultrasonic vibrations can be transmitted to the tank that stores the cleaning water for electronic materials, and in spin cleaning. Can transmit ultrasonic vibrations in the nozzle portion of the washing water for electronic material to be poured. The frequency of ultrasonic vibrations transmitted is preferably 20 kHz or more, more preferably 400 kHz or more. If the frequency of ultrasonic vibration is less than 20 kHz, the removal of fine particles from the electronic material contaminated with fine particles may be insufficient. In order to perform precision cleaning that does not damage the surface of the object to be cleaned, it is preferable to transmit ultrasonic vibrations of 400 kHz or higher, especially at high frequencies. The cleaning water for electronic materials according to the present invention has an excellent effect of removing fine particles at room temperature and can clean the surface of the electronic material with a high removal rate of fine particles. Therefore, it can be heated to a high temperature as in conventional APM cleaning. do not need. Therefore, by using the cleaning water for electronic materials of the present invention, the energy cost can be reduced and the working environment can be improved.

The cleaning water for electronic materials according to the present invention is sent from the sealed cleaning water storage tank for electronic materials to a use point through a pipe, and the excess cleaning water for electronic materials is sealed through the piping for cleaning water storage tank for electronic materials. It can be suitably used by using a supply device for cleaning water for electronic materials that is returned to and recycled. FIG. 1 shows the production of cleaning water for electronic materials according to the present invention,
It is a systematic diagram of one mode of a supply device. The raw water is sent to the gas permeable membrane module 2 in the preceding stage, where the gas phase side is kept at a reduced pressure by the vacuum pump 1, and the dissolved gas is removed. The water from which the dissolved gas has been removed is then used in the gas permeable membrane module 3 in the subsequent stage.
And the oxygen gas supplied from the oxygen gas supply device 4 is dissolved to have a predetermined concentration to become water in which the oxygen gas is dissolved at a concentration higher than the atmospheric saturation concentration. In the water in which oxygen gas is dissolved at a concentration higher than the atmospheric saturation concentration, the ammonia water is then pumped from the ammonia water storage tank 5 by the pump 6,
Hydrogen peroxide water is injected from the hydrogen peroxide water storage tank 7 by the pump 8 to prepare the electronic material cleaning water of the present invention, which is stored in the sealed electronic material cleaning water storage tank 9. The inflow amount of water in which oxygen gas is dissolved at a concentration higher than the atmospheric saturation concentration and the concentrations of ammonia and hydrogen peroxide in the cleaning water for electronic materials in the storage tank are measured, and a signal is sent to the controller to pump the ammonia by the pump 6 and the pump 8. The injection amounts of water and hydrogen peroxide water can be controlled to maintain the concentrations of ammonia and hydrogen peroxide in the cleaning water for electronic materials in the storage tank at predetermined values. The electronic-material cleaning water stored in the sealed electronic-material cleaning water storage tank 9 is sent to the use point 12 through the pipe 11 by the pump 10. Excessive cleaning water for electronic materials that has not been used at the point of use can be returned to the closed cleaning water storage tank for electronic materials through a pipe and circulated for reuse.

The cleaning water for electronic materials of the present invention which dissolves oxygen gas and contains low concentrations of ammonia and hydrogen peroxide is
Oxygen gas does not undergo self-decomposition and is extremely stable, and since the ammonia and hydrogen peroxide contained in it are also low in concentration, it is possible to maintain water quality for a long time by using a closed storage tank and supply pipe. it can. By using such a device, washing water for electronic materials can be intensively produced without installing washing water producing devices for many use points, and multiple washing water can be used through main and branch pipes. It is possible to supply cleaning water for electronic materials with stable water quality up to the point. Moreover, the excess cleaning water for electronic materials not used at the point of use can be returned to the storage tank and repeatedly sent to the point of use to form a circulation system. According to the cleaning water for electronic materials of the present invention, the amount of chemicals used for cleaning electronic materials contaminated with fine particles can be significantly reduced, and a high cleaning effect can be obtained by cleaning at room temperature. The waste liquid treatment after washing the material becomes easy. That is, since the conventional cleaning waste liquid is discharged in a high-concentration state containing a large amount of ammonia and hydrogen peroxide, it is necessary to perform a neutralization treatment or a decomposition treatment. The same amount of chemical is required. In the present invention, what is discharged is a liquid containing a low concentration of ammonia and hydrogen peroxide, and for example, it becomes a water quality that can be discharged by neutralizing by adding a small amount of acid. Of course, the water quality is also reusable as raw water. Although the amount of hydrogen peroxide contained in the waste liquid is small and does not usually cause a safety problem, hydrogen peroxide dissolved in the waste liquid can be decomposed as needed depending on the use environment. For example, by contacting water containing hydrogen peroxide with a catalyst such as platinum, palladium or manganese dioxide, hydrogen peroxide can be decomposed into water and oxygen gas, which can be removed.

[0015]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, ultrapure water was used to prepare the wash water. Example 1 A 6-inch diameter silicon wafer whose surface was oxidized with ultrapure water containing ozone was contaminated with fine alumina powder to prepare a contaminated wafer having fine alumina particles adhered to the surface. The number of adhering fine particles on this contaminated wafer was measured by a wafer / dust detecting device [Tokyo Optical Co., Ltd.] based on the laser scattered light detection method, and it was found that fine particles with a diameter of 0.2 to 0.5 μm per wafer. 1
2,600 particles, diameter of 0.5-1.0μm 31.2
The number was 00, and the number of fine particles having a diameter of 1.0 μm or more was 200, which was 44,000 in total. 500 rpm for this contaminated wafer
Rotate at 30 ° C., dissolve oxygen 30 mg / liter, wash water for electronic materials containing ammonia 10 mg / liter, hydrogen peroxide 10 mg / liter at room temperature with an ultrasonic irradiation nozzle [Pretec, Fine Jet]. Frequency 1.
While ultrasonically vibrating at 6 MHz and an output of 13.5 W / cm ² , it was poured at 800 ml / min and spin-washed for 60 seconds. Then, it was rinsed with ultrapure water and then dried. The number of adhered fine particles on the wafer surface after drying was measured in the same manner, and the diameter per wafer was 0.2
130 fine particles of ~ 0.5μm, diameter 0.5-1.0μ
There were 310 fine particles of m and 0 fine particles having a diameter of 1.0 μm or more, for a total of 440, and the removal rate of fine particles on the wafer surface was 99%. Comparative Example 1 Example 1 was repeated in the same manner as in Example 1 except that washing water at room temperature containing 10 mg / liter of ammonia and 10 mg / liter of hydrogen peroxide, but dissolving oxygen gas only in the atmospheric saturation concentration was used. The contaminated wafer prepared in 1 was washed. The number of adhered fine particles on the wafer surface after drying was determined by
Measurement was carried out in the same manner as above, but 6,400 fine particles having a diameter of 0.2 to 0.5 μm and a diameter of 0.5 were obtained per wafer.
16,500 particles of ~ 1.0μm, diameter 1.0μm
The above-mentioned fine particles were 95, totaling 22,995, and the removal rate of fine particles on the wafer surface was 48%. Comparative Example 2 With Example 1 except that so-called APM cleaning water containing 4.1% by weight of ammonia and 4.3% by weight of hydrogen peroxide was heated to 80 ° C. and ultrasonic vibration was not transmitted. Similarly, the contaminated wafer prepared in Example 1 was washed. The number of adhered fine particles on the wafer surface after drying was determined by
The measurement was performed in the same manner as in 1., and 145 fine particles having a diameter of 0.2 to 0.5 μm and a diameter of 0.5 to 0.5 per wafer.
There were 340 fine particles of 1.0 μm and one fine particle having a diameter of 1.0 μm or more, a total of 486, and the removal rate of fine particles on the wafer surface was 99%. Comparative Example 3 Using the cleaning water containing 0.41% by weight of ammonia and 0.43% by weight of hydrogen peroxide, which was prepared by diluting the APM cleaning water used in Comparative Example 10 by 10 times, in the same manner as in Example 1, at room temperature. The contaminated wafer prepared in Example 1 was washed while transmitting the ultrasonic vibration with. The number of adhered fine particles on the surface of the dried wafer was measured in the same manner as in Example 1 to find that the wafer 1
3,440 fine particles with a diameter of 0.2-0.5 μm per sheet
The number of particles was 0.5500 to 1.0 μm, the number of particles was 8,500, and the number of particles having a diameter of 1.0 μm or more was 55, which was 11,995 in total, and the removal rate of particles on the wafer surface was 73%. . Table 1 shows the composition of cleaning water, the cleaning conditions and the fine particle removal rate of Example 1 and Comparative Examples 1 to 3.

[0016]

[Table 1]

As can be seen from the results in Table 1, Example 1
The washing water for electronic materials of the present invention is the conventional AP of Comparative Example 3.
Compared to M wash water, both the contents of ammonia and hydrogen peroxide are as low as 1 / 4,000, and even though washing is performed at room temperature In cleaning contaminated wafers,
The particle removal rate is the same as that of APM cleaning. Even if the content of ammonia and hydrogen peroxide is the same as that of the cleaning water for electronic materials of Example 1, the cleaning water of Comparative Example 1 in which oxygen gas is dissolved only in the atmospheric saturation concentration has a fine particle removal rate reduced by half. From this, the effectiveness of the cleaning water for electronic materials of the present invention in which oxygen gas is dissolved at a concentration higher than the atmospheric saturation concentration is confirmed. Further, in the cleaning water of Comparative Example 3 in which the concentrations of ammonia and hydrogen peroxide in the conventional APM cleaning water were set to 1/10, the particle removal rate was reduced to about 70% even if ultrasonic vibration was transmitted. It can be seen that high-temperature washing water containing a high concentration of chemicals is indispensable for effective washing.

[0018]

EFFECTS OF THE INVENTION Since the cleaning water for electronic materials of the present invention dissolves oxygen gas at a concentration higher than the atmospheric saturation concentration, the contents of ammonia and hydrogen peroxide are significantly lower than those of conventional APM cleaning water. Nevertheless, it has the same fine particle removing effect as the conventional APM cleaning. The cleaning water for electronic materials of the present invention is an extension of the conventional APM cleaning water in that it contains ammonia and hydrogen peroxide.
The existing equipment of the mass production factory can be used as it is, and there is no obstacle in application.

[Brief description of drawings]

FIG. 1 is a system diagram of one embodiment of a device for producing and supplying cleaning water for electronic materials according to the present invention.

[Explanation of symbols]

1 vacuum pump 2 Gas permeable membrane module in the first stage 3 Gas permeable membrane module in the latter stage 4 Oxygen gas supplier 5 Ammonia water storage tank 6 pumps 7 Hydrogen peroxide water storage tank 8 pumps 9 Electronic material wash water storage tank 10 pumps 11 piping 12 Use points

Continuation of front page (56) Reference JP-A-11-158494 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C11D 7 / 02,7 / 18,7 / 60 B08B 3 / 08 H01L 21/304 647

Claims (2)

(57) [Claims] 1. A method for dissolving oxygen gas at a concentration higher than the saturation concentration in the atmosphere and containing 0.1 to 10,000 mg / liter of ammonia and 0.1 to 10,000 mg / liter of hydrogen peroxide. Cleaning water for electronic materials. 2. The cleaning water for electronic materials according to claim 1, wherein the electronic material that is the object to be cleaned is a silicon substrate for semiconductors, a glass substrate for liquid crystals, or a quartz substrate for photomasks.