JPH10128253A - Washing method for electronic members and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of an oxidized film and surface roughness on the surface of electronic members by washing the electronic members with an acidic washing liq. obtained by dissolving gaseous hydrogen to ultrapure water and dissolving an acid or an acidic gas to the ultrapure water and having negative oxidation-reduction potential. SOLUTION: Before introducing the ultrapure water produced with an ultrapure water production device 1 to a gas dissolving tank 2, a dissolved oxygen is removed in a degasing device 5 and the ultrapure water is supplied to the gas dissolving tank 2, and the gaseous hydrogen supplied from an ultrapure water electrolyzing device through a gas permeating membrane is dissolved in the ultrapure water. The ultrapure water dissolving the gaseous hydrogen is supplied to a pH adjusting device 3 from a feed pipe 13, and the acid or the acidic gas is dissolved in the ultrapure water to obtain an acidic washing liq. having negative oxidation-reduction potential. This acidic washing liq. is sent to the washing tank 4, and a material 6 to be washed is washed with the acidic washing liq. In this way, a sure washing is executed without generating the oxidized film and the surface dry spot on the surface of the electronic members.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning electronic parts such as a semiconductor substrate, a glass substrate, an electronic part, and parts for manufacturing these components.

[0002]

2. Description of the Related Art In the process of manufacturing electronic parts such as LSIs, it is sometimes required to make the surface extremely clean. For example, in LSI, a silicon oxide insulating film is formed on a silicon wafer, a resist layer is provided in a predetermined pattern on the silicon film, and the insulating film in a portion where the resist layer is not provided is removed by etching or the like to remove metal silicon. After exposing the surface and cleaning the surface, a step (lithography process) of introducing a p-type or n-type element according to the purpose and embedding a metal wiring such as aluminum is repeated to manufacture an element. When introducing an n-type element or embedding metal wiring, if foreign matter such as fine particles, metal, organic matter, natural oxide film, etc. adhere to the metal silicon surface, the metal silicon and the metal wiring may The characteristics of the element may be poor due to poor contact or increased contact resistance. For this reason, in the LSI manufacturing process, the step of cleaning the surface of the silicon wafer is a very important step for obtaining a high-performance device, and it is necessary to remove impurities adhering to the silicon wafer as much as possible.

Conventionally, the cleaning of a silicon wafer is a combination of cleaning with a mixed solution of sulfuric acid and hydrogen peroxide, a mixed solution of hydrochloric acid and hydrogen peroxide, a hydrofluoric acid solution, an ammonium fluoride solution, and the like, and cleaning with ultrapure water. This removes organic substances, fine particles, metals, natural oxide films and the like adhering to the silicon wafer surface without deteriorating the flatness of the silicon wafer surface at the atomic level.

The following (1) to (13) are specific examples of a conventional silicon wafer cleaning process. (1) Sulfuric acid / hydrogen peroxide washing step: a mixed solution of sulfuric acid: hydrogen peroxide = 4: 1 (volume ratio) at 130 ° C. for 10
Minute wash. (2) Ultrapure water washing step; washing with ultrapure water for 10 minutes. (3) Hydrofluoric acid washing step; washing with 0.5% hydrofluoric acid for 1 minute. (4) Ultrapure water washing step; washing with ultrapure water for 10 minutes. (5) Ammonia / hydrogen peroxide water washing step; washing with a mixed solution of ammonia water / hydrogen peroxide / ultra pure water = 0.05: 1: 5 (volume ratio) at 80 ° C. for 10 minutes. (6) Ultrapure water washing step; washing with ultrapure water for 10 minutes. (7) Hydrofluoric acid washing step: washing with 0.5% hydrofluoric acid for 1 minute. (8) Ultrapure water washing step: washing with ultrapure water for 10 minutes. (9) Hydrochloric acid / hydrogen peroxide water washing step: a mixed solution of hydrochloric acid: hydrogen peroxide water: ultra pure water = 1: 1: 6 (volume ratio)
Wash at 80 ° C for 10 minutes. (10) Ultrapure water washing step; washing with ultrapure water for 10 minutes. (11) Hydrofluoric acid washing step; washing with 0.5% hydrofluoric acid for 1 minute. (12) Ultrapure water washing step; washing with ultrapure water for 10 minutes. (13) Spin drying or IPA vapor drying

The step (1) is mainly for removing organic substances adhering to the surface of the silicon wafer,
The step (5) is mainly for removing fine particles adhering to the silicon wafer surface, and the step (9) is mainly for removing metal impurities on the silicon wafer surface. Steps (3), (7) and (11) are performed to remove the natural oxide film on the surface of the silicon wafer. In addition, the cleaning liquid in each of the above steps often has a contaminant removing ability other than the above-mentioned main purpose. For example, the mixed solution of sulfuric acid and hydrogen peroxide used in the step (1) is not only organic but also organic substances. Since it also has a strong action of removing metal impurities, in addition to the above-described method of removing different impurities by each cleaning solution, there is also a method of removing a plurality of impurities with one type of cleaning solution.

In the silicon wafer cleaning step, a method of bringing a cleaning liquid or ultrapure water into contact with the silicon wafer surface is generally called a batch cleaning method in which a plurality of silicon wafers are immersed in a cleaning tank containing the cleaning liquid or ultrapure water. Although the method is adopted, in order to prevent contamination of the cleaning liquid, a method of cleaning while circulating and filtering the cleaning liquid, and a cleaning method using ultrapure water after treatment with the cleaning liquid, supplying ultrapure water from the bottom of the cleaning tank. An overflow cleaning method that overflows from the top of the cleaning tank and a quick dump cleaning method that stores ultrapure water in the cleaning tank until the entire surface of the wafer is immersed in ultrapure water, and then discharges the ultrapure water from the bottom of the cleaning tank at once Etc. have also been adopted. In recent years, in addition to the batch cleaning method, a method of spraying a cleaning liquid or ultrapure water on a wafer surface in a shower shape or cleaning the wafer by rotating the wafer at a high speed and spraying a cleaning liquid or ultrapure water on the center thereof. A so-called single wafer cleaning method such as a method is also employed.

The cleaning with ultrapure water is performed to rinse (rinse) a cleaning liquid or the like remaining on the wafer surface. Therefore, the ultrapure water used for rinsing is high purity ultrapure water from which fine particles, colloidal substances, organic substances, metal ions, anions, dissolved oxygen and the like have been removed to an extremely low level. This ultrapure water is also used as a solvent for the cleaning liquid.

[0008]

By the way, in recent years, LSI
The lithography process in the LSI manufacturing process was about several times in the early days, but increased from 20 to 30 times. With the increase.
For this reason, the cost of the cleaning liquid and ultrapure water used for cleaning the wafer, the cost of processing the used cleaning liquid and ultrapure water, and the cleaning liquid gas generated in the clean room due to the high temperature cleaning process are discharged from the clean room. The air cost etc. of this product increase, which leads to an increase in product cost.

Therefore, it is necessary to reduce the concentration and use amount of the cleaning solution, lower the temperature of the cleaning process, reduce the number of steps per cleaning process, and reduce the amount of ultrapure water used for rinsing. However, it is also important to reduce the cost in such a cleaning process and to clean the surface of a silicon wafer or the like to a completely clean surface without surface roughness.

However, as described above, in the conventional cleaning process, the natural oxide film formed on the surface of the silicon wafer is removed by hydrofluoric acid cleaning and then rinsed with ultrapure water. , There is a possibility that the following problems may occur.

First, in order to prevent oxidation of the silicon wafer surface due to dissolved oxygen, ultrapure water that has been degassed to a dissolved oxygen concentration of 10 ppm or less is used. Since it is not structured, oxygen gas in the atmosphere is instantaneously dissolved in ultrapure water in the cleaning tank (the dissolved oxygen concentration rises to about 100 ppm), and cleaning is performed using such ultrapure water. Is performed, the surface of the silicon wafer is easily oxidized. In particular, in the case of n + silicon, which is easily oxidized, there is a problem that an oxide film of several angstroms is easily formed.

Second, even if the cleaning tank is constructed in an airtight structure in order to solve the above-mentioned problem caused by the dissolution of oxygen gas in the atmosphere into ultrapure water, even if the ultrapure water is neutral, There are 10 ^-7 moles of hydroxyl ions per liter, and the hydroxyl ions etch the silicon wafer surface,
There has been a problem that the surface is easily roughened to a depth of several angstroms. In addition, there is a problem that silicon etched by hydroxyl ions adheres to the surface of the silicon wafer, causing clouding and the like on the surface of the silicon wafer.

The present inventors have conducted various studies to solve the above problems, and as a result, dissolved hydrogen gas in ultrapure water.
When the rinsing is performed using an acidic cleaning solution whose pH is adjusted to an acidic side of less than 7 while having a negative oxidation-reduction potential, there is no possibility of forming an oxide film on the silicon wafer surface due to dissolved oxygen, and silicon The inventors have found that the surface roughness of the wafer can be prevented, and have completed the present invention based on this finding.

An object of the present invention is to provide a method and an apparatus for cleaning electronic component members, which can perform reliable cleaning without causing an oxide film or surface roughness on the surface of electronic component members such as silicon wafers. It is intended for.

[0015]

The present invention is characterized in that (1) electronic component members are cleaned by dissolving hydrogen gas in ultrapure water and using an acidic cleaning solution having a negative oxidation-reduction potential. (2) The method for cleaning electronic parts and members according to (1), wherein the acidic cleaning liquid dissolves 0.05 ppm or more of hydrogen gas. (1) The method for cleaning electronic component members according to (1) or (2), wherein the acidic cleaning solution has a pH of less than 7 or 3 or more, and (4) the acidic cleaning solution has a dissolved gas concentration of less than 10 ppm. (1) The method for cleaning electronic component members according to any one of (1) to (3), wherein (5) cleaning is performed while irradiating ultrasonic waves. Electronic component members according to any one of (1) to (4) (6) The method for cleaning electronic component members according to any one of (1) to (5), wherein the temperature of the acidic cleaning solution is adjusted to 20 ° C. to 60 ° C. for cleaning. (7) The method for cleaning electronic component members according to any one of (1) to (6), wherein hydrogen gas is dissolved in ultrapure water through a gas permeable membrane, (8) ultrapure water A production apparatus, gas dissolving means for dissolving hydrogen gas in ultrapure water, pH adjusting means for adjusting pH to less than 7, and hydrogen gas dissolved in ultrapure water, and A cleaning unit for cleaning electronic parts and components with an acidic cleaning liquid having a reduction potential; and (9) a concentration of dissolved hydrogen dissolved in the acidic cleaning liquid and a solution of the solution. Dissolved hydrogen concentration detection means for detecting pH, pH detection means, Based on the dissolved hydrogen concentration and pH of the detection results, the dissolved hydrogen concentration control means for controlling each of the dissolved hydrogen concentration and pH of the acidic cleaning solution, p
(8) The apparatus for cleaning electronic components and members according to (8), characterized by having H control means, (10) Ultrasonic irradiation means for irradiating ultrasonic waves to the cleaning section (8) Alternatively, the gist is a cleaning device for electronic component members described in (9).

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of the present invention, various components and materials used in the electronic component manufacturing field and the like are listed as electronic component members (objects to be cleaned) to be cleaned. Substrate materials such as semiconductor substrates such as III-V semiconductor wafers, glass substrates for liquid crystal, etc., finished products and semi-finished products such as electronic components such as memory devices, CPUs and sensor devices, quartz reaction tubes, cleaning tanks, substrate carriers And the like for an electronic component manufacturing apparatus. In the present invention, ultrapure water is obtained by treating raw water such as industrial water, clean water, well water, river water, lake water, etc. with a pretreatment device such as coagulation sedimentation, filtration, coagulation filtration, and activated carbon treatment. By removing coarse suspended substances, organic substances, etc. in the water, and then treating with a primary pure water production apparatus mainly composed of a desalination apparatus such as an ion exchange apparatus and a reverse osmosis membrane apparatus, fine particles, colloidal substances, organic substances, Most of the impurities such as metal ions and anions are removed, and the primary pure water is further purified by an ultraviolet irradiation device, a mixed-bed polisher, a membrane treatment device equipped with an ultrafiltration membrane or a reverse osmosis membrane. It refers to high-purity pure water from which impurities such as fine particles, colloidal substances, organic substances, metal ions, and anions have been removed as much as possible by circulating treatment in the production equipment. 17.0M
Ω · cm or more, total organic carbon is 100 μgC / liter or less, the number of fine particles (particle size of 0.07 μm or more) is 50 / ml or less, the viable bacterial count is 50 / liter or less,
It refers to silica having a silica content of 10 μg SiO ₂ / liter or less and sodium of 0.1 μg Na / liter or less. In the apparatus of the present invention, the ultrapure water production apparatus refers to a combination of the above-described pretreatment apparatus, primary pure water production apparatus, and secondary pure water production apparatus. In addition, after the primary pure water production apparatus, a case where a deaerator such as a vacuum deaerator or a membrane deaerator using a gas permeable membrane is added may be added, and the raw water may be industrial water,
Water, well water, river water, lake water, etc. may be used in which various types of recovered water collected in the factory are mixed.

FIG. 1 shows an example of an apparatus for cleaning electronic parts and members of the present invention. In the figure, reference numeral 1 denotes an ultrapure water production apparatus, 2 denotes a gas dissolving tank, 3 denotes a pH adjusting apparatus, and 4 denotes a cleaning tank. The apparatus further includes a degassing apparatus 5 for removing gas dissolved in the ultrapure water produced by the ultrapure water producing apparatus 1 and a cleaning target to be cleaned in the cleaning tank 4, if necessary. An ultrasonic irradiation device 7 for irradiating the object 6 with ultrasonic waves is provided.

The ultrapure water producing apparatus 1 includes a pretreatment device for treating raw water with a coagulating sedimentation device, a sand filtration device, and an activated carbon filtration device, and a reverse osmosis membrane device, a two-bed three-column ion exchange device. , A mixed-bed ion exchange device, a primary-pure water production device that obtains primary purified water by processing with a precision filter, and a primary-purified water that is subjected to ultraviolet irradiation, a mixed-bed polisher, and an ultrafiltration membrane treatment. A secondary pure water producing apparatus for removing fine particles, colloidal substances, organic substances, metal ions, anions and the like remaining in the apparatus is provided, and a degassing apparatus is further provided if necessary (neither is shown). .

The ultrapure water produced by the ultrapure water production apparatus 1 preferably has, for example, the water qualities shown in Table 1 below. It is said that no contaminants therein adhere to the wafer surface.

[0020]

[Table 1]

Hydrogen gas is dissolved in the ultrapure water produced by the ultrapure water producing apparatus 1 in a gas dissolving tank 2. Since ultrapure water is usually subjected to degassing at the time of production, the dissolved oxygen concentration in the ultrapure water is very low, but the dissolved oxygen is not completely removed. However, by dissolving hydrogen gas in ultrapure water, the above-mentioned adverse effect of dissolved oxygen can be eliminated by setting the oxidation-reduction potential of the liquid to a negative value, and usually, the dissolved hydrogen concentration at 25 ° C. and 1 atm. 0.05 ppm or more, especially 0.8
It is preferable to dissolve hydrogen gas in the gas dissolving tank 2 so that the concentration becomes about 1.6 ppm. If the dissolved hydrogen concentration is less than 0.05 ppm, the oxidation-reduction potential of the liquid may not be able to be reliably set to a negative value. In addition, when the dissolved hydrogen concentration in ultrapure water is less than 0.05 ppm,
In the case where the removal of dissolved oxygen in the ultrapure water is insufficient, for example, the dissolved oxygen remaining in the ultrapure water is further removed by the degassing device 5 before the ultrapure water is introduced into the gas dissolving tank 2. It is preferable to keep it.

In the process of producing ultrapure water, nitrogen gas is usually enclosed in a treatment tank for performing various treatments, so that ultrapure water dissolves nitrogen gas. Dissolved nitrogen in ultrapure water does not necessarily need to be removed because there is no risk of oxidizing or etching the silicon wafer surface, etc.However, when irradiating ultrasonic waves during cleaning with nitrogen gas dissolved, In addition, ammonium ions may be generated to increase the pH of the solution. For this reason, when irradiating an ultrasonic wave at the time of washing, it is preferred that ultrapure water is treated by the degassing device 5 to remove dissolved nitrogen in the ultrapure water.

In the degassing device 5, it is preferable to remove particularly oxygen gas and nitrogen gas dissolved in the ultrapure water, and the concentration of one or more of these dissolved gases is 10% or less.
It is preferable to degas so as to be less than ppm, preferably 2 ppm or less. The dissolved gas concentration is 10p
When the pressure is equal to or more than pm, air bubbles are generated at the time of cleaning, the air bubbles adhere to the object to be cleaned, and the cleaning effect on the portion where the air bubbles are adhered tends to decrease. In the degassing device 5, as a method for degassing the dissolved gas in the ultrapure water, a method of vacuum degassing via a gas permeable membrane is preferable.

As a method of dissolving hydrogen gas in ultrapure water, a method of injecting hydrogen gas into ultrapure water via a gas permeable membrane and dissolving the same, and a method of dissolving hydrogen gas in ultrapure water by bubbling hydrogen gas A method in which hydrogen gas is dissolved in ultrapure water through an ejector, a method in which hydrogen gas is supplied to the upstream side of a pump that supplies ultrapure water to the gas dissolving tank 2, and the gas is dissolved by stirring in the pump. Can be As the hydrogen gas dissolved in the ultrapure water in the gas dissolving tank 2, it is preferable to use a high-purity hydrogen gas generated by electrolyzing ultrapure water.

As the gas permeable membrane in the gas dissolving tank 2 or the degassing device 5, a large number of gas permeable materials such as silicon or a film made of a water-repellent material such as a fluororesin can be used. For example, a member provided with fine holes and configured to transmit gas but not water can be used. The gas permeable membrane can be used as a hollow fiber structure, and when the gas permeable membrane is formed in a hollow fiber structure, a method of allowing gas to permeate from the inner side of the hollow fiber to the outside as a method of degassing or gas dissolving, Any of the methods of transmitting gas from the outside of the hollow fiber to the inner space side can be adopted. FIG. 2 shows an example in which hydrogen gas obtained by electrolyzing ultrapure water is dissolved in ultrapure water in a gas dissolving tank 2. In FIG. 2, reference numeral 8 denotes an ultrapure water electrolyzer, and ultrapure water introduced into the ultrapure water electrolyzer 8 from the ultrapure water supply pipe 9 is electrolyzed in the electrolyzer 8, and a cathode of the electrolyzer 8 is used. The high-purity hydrogen gas generated in the chamber is supplied to the hydrogen gas supply pipe 1
By 0, it is sent to the gas dissolving tank 2.

In the gas dissolving tank 2, the hydrogen gas supplied from the ultrapure water electrolysis device 8 through the gas permeable membrane 11 is added to the ultrapure water supplied from the ultrapure water supply pipe 12 to the gas dissolving tank 2. The ultrapure water in which the hydrogen gas is dissolved is sent from the supply pipe 13 to the pH adjusting device 3. In FIG. 2, reference numeral 14 denotes a drain valve for discharging ultrapure water after electrolysis, 15 a pressure gauge for measuring the hydrogen gas pressure in the gas dissolving tank 2, and 16 a hydrogen gas supplied to the gas dissolving tank 2. An exhaust processing device 17 for performing exhaust processing is a supply hydrogen gas amount control device.

After dissolving the hydrogen gas in the ultrapure water in the gas dissolving tank 2, the pH is adjusted to less than 7 in the pH adjuster 3, preferably the pH is less than 7, 3 or more, more preferably 4 to 6 Adjust to the range.

In order to adjust the pH, a method of dissolving an acid or acidic gas in ultrapure water in which hydrogen gas is dissolved is employed. As the acid, for example, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, etc. are used, and as the acid gas, for example, carbon dioxide gas is used. However, the method of dissolving the carbon dioxide gas and adjusting the pH is affected by coexisting ions. Is preferred because of the small amount. When using an acid for pH adjustment,
The adjusting device 3 is, for example, as shown in FIG.
And a pump 24, and a method is adopted in which an acid is added and mixed in the middle of a pipe for supplying a liquid from the gas dissolving tank 2 to the cleaning tank 4. In FIG. 3, reference numeral 25 denotes a control valve for adjusting the supply amount of the acid.

When an acidic gas such as carbon dioxide is added for pH adjustment, the pH adjusting device 3 can be composed of, for example, an acid gas supply device 26 and a gas dissolving tank 27 as shown in FIG. . As the gas dissolving tank 27, one having the same structure as the gas dissolving tank 2 for dissolving the hydrogen gas can be used.

The acidic cleaning solution whose pH has been adjusted by the pH adjusting device 3 is sent to the cleaning tank 4. As described above, the cleaning solution has a pH of less than 7 and dissolves hydrogen gas to produce a negative oxidation-reduction solution. It is necessary to have a potential. For this reason, an oxidation-reduction potentiometer 18, a dissolved hydrogen concentration meter 19, and a hydrogen ion concentration meter 20 are provided in the middle of the cleaning liquid supply pipe 22 for supplying the cleaning liquid to the cleaning tank 4, and the oxidation-reduction potential, the dissolved hydrogen concentration, and the It is preferable that the pH is constantly monitored to control the amount of hydrogen gas dissolved in ultrapure water in the gas dissolving tank 2 and the amount of acid or acid gas added in the pH adjusting device 3.

As a method of cleaning the object 6 to be cleaned in the cleaning tank 4 with an acidic cleaning liquid, the method of cleaning the object 6
Washing method, in which the cleaning liquid is supplied from the bottom side of the cleaning tank 4 and overflows from the upper part of the cleaning tank 4, while the cleaning liquid is supplied from the bottom side of the cleaning tank 4. Examples of the method include a flow cleaning method of cleaning, a method of spraying a cleaning liquid onto the object 6 to be cleaned in a shower shape, and a method of spraying a cleaning liquid on the object 6 rotated at a high speed to perform cleaning.

The cleaning tank 4 is provided with a heater 21 so that the temperature of the cleaning liquid can be adjusted as required.
In order to obtain a better cleaning effect, the cleaning solution should be 20 to 60
It is preferable that the temperature is adjusted to ° C. for washing. It is more effective to use ultrasonic irradiation at the time of cleaning. The ultrasonic wave generated from the ultrasonic irradiation device 7 has a frequency of 30 kHz or more. When irradiating ultrasonic waves, for example, in a batch cleaning method, a method of irradiating the object to be cleaned 6 in a state where the object to be cleaned 6 is immersed in the cleaning liquid supplied into the cleaning tank 4 is adopted. In the case of the method of washing by spraying, a method of irradiating the cleaning liquid with ultrasonic waves at an upstream portion of the cleaning liquid injection nozzle is adopted.

When using ultrasonic irradiation at the time of cleaning, it is preferable that a rare gas is further dissolved in the cleaning liquid. Examples of the rare gas include helium, neon, argon, krypton, and xenon, or a mixture of two or more of them. It is preferable that the rare gas is dissolved in the cleaning solution at 0.05 ppm or more. Dissolution of the rare gas is preferably performed in a step after degassing oxygen gas, nitrogen gas, and the like dissolved in the ultrapure water in the degassing device 5. It is preferable to perform the dissolution of the hydrogen gas in the tank 2 simultaneously or continuously. As a method for dissolving the rare gas, a method similar to the method for dissolving hydrogen gas in ultrapure water can be employed.

The cleaning apparatus of the present invention preferably has a gas seal structure in order to prevent oxygen gas from the atmosphere from being mixed into ultrapure water or the cleaning liquid. In the above example, the case where the hydrogen gas is dissolved in the ultrapure water in the gas dissolving tank 2 and then the pH is adjusted by the pH adjusting device 3 is shown. However, the hydrogen gas is dissolved after the pH adjustment is performed. May be.

[0035]

The present invention will be described below in further detail with reference to examples and comparative examples. Example 1 A 6-inch silicon wafer substrate (n + Si100) from which surface impurities were removed by RCA cleaning was immersed in 0.5% diluted hydrofluoric acid for 10 minutes to treat the wafer surface. Next, the wafer was washed with a cleaning solution having the composition shown in Table 2 using the cleaning apparatus shown in FIG. 1, and then spin-dried. The pH of the cleaning solution was adjusted with hydrochloric acid as shown in FIG.
This was performed using an H adjusting device. Table 2 shows the results of measuring the oxide film thickness and surface roughness of the wafer surface before and after the treatment with the cleaning liquid.
It is shown along with

[0036]

[Table 2]

The value of the oxide film thickness on the wafer surface in Table 2 is 25
The average value was measured for each of the wafers using a photoelectron X-ray analyzer (ESCA-200 manufactured by Seiko Instruments Inc.). Further, the value of the roughness of the wafer surface was determined by using an atomic force microscope (Seiko Denshi Kogyo: S
PI-3600), and the average value was shown.

Comparative Example 1 Except for using ultrapure water shown in Table 2 in place of the acidic cleaning solution,
The same processing as in Example 1 was performed. The results of measuring the oxide film thickness and surface roughness of the wafer surface before and after treatment with ultrapure water are also shown in Table 2.

Example 2 A 6-inch silicon wafer substrate (n + Si100) from which surface impurities were removed by RCA cleaning was immersed in 0.5% diluted hydrofluoric acid for 10 minutes to treat the wafer surface. Next, the wafer was washed with a cleaning solution having the composition shown in Table 2 using the cleaning apparatus shown in FIG. 1, and then spin-dried. The pH of the cleaning solution was adjusted with carbon dioxide using the pH adjusting device shown in FIG. The results of measuring the oxide film thickness and surface roughness of the wafer surface before and after the treatment with the cleaning liquid are also shown in Table 2.

[0040]

According to the cleaning method of the present invention, in a process of cleaning electronic parts such as a silicon wafer,
Compared to the conventional method of cleaning the wafer surface with ultrapure water,
There is no danger of roughening the surface of electronic component members or forming a thick oxide film on the surface,
There is an effect that a completely clean surface can be easily washed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a cleaning device of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a hydrogen gas dissolving unit.

FIG. 3 is a configuration diagram illustrating an example of a pH adjusting device.

FIG. 4 is a configuration diagram showing a different example of the pH adjusting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrapure water production apparatus 2 Gas dissolution tank 3 pH adjustment apparatus 4 Cleaning tank 6 Object to be cleaned 7 Ultrasonic irradiation apparatus 19 Dissolved hydrogen concentration meter 20 Hydrogen ion concentration meter

Claims (10)

[Claims] 1. A method for cleaning electronic component members, wherein the electronic component members are cleaned by dissolving hydrogen gas in ultrapure water and using an acidic cleaning liquid having a negative oxidation-reduction potential. 2. The method for cleaning electronic component members according to claim 1, wherein the acidic cleaning solution dissolves hydrogen gas of 0.05 ppm or more. 3. The method for cleaning electronic component members according to claim 1, wherein the pH of the acidic cleaning solution is less than 7 and 3 or more. 4. The acidic cleaning solution has a dissolved gas concentration of 10 pp.
The method for cleaning electronic component members according to any one of claims 1 to 3, wherein ultrapure water degassed so as to be less than m is used. 5. The method for cleaning electronic component members according to claim 1, wherein the cleaning is performed while irradiating ultrasonic waves of 30 kHz or more. 6. The method for cleaning electronic parts and components according to claim 1, wherein the temperature of the acidic cleaning liquid is adjusted to 20 ° C. to 60 ° C. for cleaning. 7. The method for cleaning electronic component members according to claim 1, wherein hydrogen gas is dissolved in ultrapure water through a gas permeable membrane. 8. An ultrapure water production apparatus, gas dissolving means for dissolving hydrogen gas in ultrapure water, pH adjusting means for adjusting pH to less than 7, and hydrogen gas in ultrapure water. A cleaning unit for cleaning electronic component members with an acidic cleaning solution having a negative oxidation-reduction potential and dissolved therein, the cleaning device for electronic component members. 9. A dissolved hydrogen concentration detecting means and a pH detecting means for detecting the concentration of dissolved hydrogen dissolved in the acidic cleaning solution and the pH of the solution, respectively, and the dissolved hydrogen concentration and pH thereof.
9. The cleaning device for electronic parts and components according to claim 8, further comprising a dissolved hydrogen concentration control means and a pH control means for controlling the dissolved hydrogen concentration and the pH in the acidic cleaning liquid based on the detection result of the above. 10. The cleaning apparatus for electronic parts and members according to claim 8, further comprising an ultrasonic wave irradiator for irradiating the cleaning section with ultrasonic waves.