JP2002176025A - Semiconductor substrate cleaning device and method of cleaning semiconductor substrate using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent impurities and foreign matters contained in a hydrofluoric acid, pure water, and isopropyl alcohol used at the time of cleaning and drying a substrate and metallic impurities and foreign matters deposited on the rear surface or edge of the substrate from adhering to the surface of the substrate, after the substrate is treated with the hydrofluoric acid and, in addition, from deteriorating the characteristics and yield of a device in a succeeding process. SOLUTION: A nitrogen supply line equipped with an oxidizing gas supplying means is provided in a hermetically sealed chamber. The adhesion of the impurities and foreign matters to the surface of the substrate after the substrate is treated with the hydrofluoric acid is suppressed by forming a natural oxide film on the surface of the substrate in a treating vessel provided in the chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning a semiconductor substrate, and more particularly to a cleaning apparatus for cleaning a semiconductor substrate using a hydrofluoric acid aqueous solution in a closed chamber and a cleaning method using the cleaning apparatus. It is.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a semiconductor device, for cleaning a semiconductor substrate (wafer) or etching a silicon oxide film formed on the semiconductor substrate, hydrofluoric acid is used in a closed chamber provided with a processing tank. 2. Description of the Related Art A substrate cleaning apparatus that performs a series of processing such as processing, washing, and drying is used. FIG.
FIG. 1 is a schematic view showing a conventional apparatus. Referring to FIG. 11, a treatment tank 2 for immersing and washing a hydrofluoric acid aqueous solution in a closed chamber 1 is provided, and a pure water line 7 having a supply unit 6 for a hydrofluoric acid aqueous solution is provided in this processing tank 2. It is connected. Further, an IPA (isopropyl alcohol) vapor nozzle 11 for drying the wafer 15 is provided in the closed chamber 1, and a nitrogen line 5 having an IPA vapor supply unit 4 is connected to the nozzle 11. Wafer 15
Is moved in and out of the cassette by a transfer robot (not shown), and is immersed in the processing tank 2 and moved to the upper part of the processing tank 2 during drying. Next, a series of processing flows of the cleaning operation of the semiconductor substrate (wafer) 15 will be described with reference to the substrate processing flowchart of FIG. First, pure water is supplied into the processing tank 2, and the wafer 15 is moved and immersed in the processing tank 2. Next, a hydrofluoric acid aqueous solution is supplied and immersion treatment is performed for a predetermined time. Next, pure water is supplied, and a water washing process is performed to drive the hydrofluoric acid aqueous solution out of the treatment tank 2. During a series of processes from moving the wafer 15 into the closed chamber 1 to washing with water, nitrogen gas is supplied from the nozzle 11 into the closed chamber 1 and the closed chamber 1 is filled with nitrogen gas and has no oxygen. It has become. Next, a mixed gas of IPA vapor and nitrogen gas is supplied from the IPA vapor supply means 4 into the closed chamber 1 through the nozzle 11, and the inside of the chamber 1 is filled with IPA vapor and nitrogen. Next, when the wafer 15 is lifted from the processing tank 2,
Water droplets adhering to the surface of the wafer 15 are replaced by IPA vapor and drying is performed. Such a process prevents water droplets remaining on the surface of the wafer 15 during drying, so-called water marks, from being generated. Since the watermark is generated in a state where water and oxygen coexist, the generation of the watermark is prevented by keeping the atmosphere in the chamber 1 free of oxygen when the wafer 15 is dried.

In such a conventional cleaning apparatus, however, hydrofluoric acid, pure water, IPA,
Impurities contained in a trace amount in nitrogen gas, etc.
In some cases, impurities and foreign matter adhering to the back surface or edge of the semiconductor device adhere to the wafer 15 and exert an adverse effect, resulting in a decrease in characteristics and yield of the semiconductor device.
Dissolved oxygen contained in pure water has been reduced to several ppt levels due to recent development of high-purity technology, and a natural oxide film on the surface of the silicon substrate 15 hardly grows in pure water without dissolved oxygen. In particular, when a series of processes are performed in the closed chamber 1 in a state filled with nitrogen as described above, the surface of the silicon substrate 15 is not oxidized at all, and
The solid surface has a problem that metal impurities and foreign matter tend to adhere to the surface, so that a small amount of impurities adhere to the device, which causes deterioration of device characteristics and, consequently, yield. That is, in the conventional cleaning apparatus and method, a natural oxide film for protecting the surface of the silicon substrate is not formed.

[0004]

Since the conventional semiconductor substrate cleaning apparatus is configured as described above, when the apparatus is used, impurities contained in the material used for cleaning and adhere to the wafer. Under the influence of impurities and foreign matters, there is a problem that the device characteristics are deteriorated and the yield is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an apparatus and a method for cleaning a semiconductor substrate in which the influence of impurities and foreign substances adhering to the substrate surface during and after the substrate cleaning operation is reduced. An object of the present invention is to provide a cleaning method using the apparatus.

[0006]

According to the present invention, there is provided an apparatus for cleaning a semiconductor substrate, wherein a wafer processing tank is provided in a closed chamber having a nitrogen supply line having an oxidizing gas supply means and an IPA vapor supply means. The wafer processing tank is provided with a pure water supply line having hydrofluoric acid supply means.

Further, a wafer processing tank is provided in a closed chamber having a nitrogen supply line having IPA vapor supply means, and the wafer processing tank has pure water provided with hydrofluoric acid supply means and oxidizing gas mixing means. A supply line is provided.

Further, a wafer processing tank is provided in a closed chamber having a nitrogen supply line provided with IPA vapor supply means, and the wafer processing tank is provided with a hydrofluoric acid supply means and a hydrogen peroxide solution supply means. A water supply line is provided.

In addition, first and second wafer processing tanks are provided in a closed chamber having a nitrogen supply line provided with an oxidizing gas supply means and an IPA vapor supply means,
The first wafer processing tank is provided with a first pure water supply line having hydrofluoric acid supply means, and the second wafer processing tank is provided with a second pure water supply line.

Further, a wafer processing tank is provided in a closed chamber having a nitrogen supply line provided with an oxidizing gas supply means and an IPA vapor supply means, and the wafer processing tank is provided with pure water having a hydrofluoric acid supply means. A supply line is provided, and a drain line is provided.

Further, in the method of cleaning a semiconductor substrate according to the present invention, the wafer is washed with water, treated with hydrofluoric acid in a closed chamber,
After the water washing, a step of forming a natural oxide film on the wafer surface with an oxidizing gas is provided.

Further, the method has a step of forming a natural oxide film on the surface of the wafer by supplying pure water mixed with an oxidizing gas after washing the wafer with water and treating with hydrofluoric acid in a closed chamber.

Further, the method includes a step of forming a natural oxide film on the wafer surface by supplying a hydrogen peroxide solution after the wafer is washed with water, treated with hydrofluoric acid, and washed with water in a closed chamber.

Further, the method includes the steps of washing the wafer with water in a first wafer processing tank in a sealed chamber, hydrofluoric acid treatment, washing with water in a second wafer processing tank, and forming a natural oxide film on the wafer surface with an oxidizing gas. Have

Further, the wafer is washed with water in a closed chamber, an oxidizing gas is supplied after hydrofluoric acid treatment, a hydrofluoric acid aqueous solution is drained, and then pure water is supplied to form a natural oxide film on the wafer surface. It has a process.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a semiconductor substrate cleaning apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a cleaning apparatus, wherein 1 is a closed chamber, 2 is a wafer processing tank provided in the closed chamber, 3 is an oxidizing gas supply means, 4 is an IPA (isopropyl alcohol) vapor supply means, These are provided in the nitrogen supply line 5. Reference numeral 7 denotes a pure water supply line provided with a hydrofluoric acid supply means 6. Numeral 11 denotes a nozzle for jetting nitrogen gas, IPA vapor and a mixed gas thereof from the nitrogen supply line 5 into the closed chamber 1. Reference numeral 12 denotes a drain port provided in the closed chamber. Reference numeral 15 denotes a semiconductor substrate (wafer). Next, the operation will be described with reference to the processing flowchart of the substrate of FIG. First, a nitrogen gas is supplied from the nitrogen supply line 5 into the closed chamber 1, and pure water is supplied from the pure water supply line 7 into the treatment tank 2. The wafer 15 is moved and immersed in the processing tank 2 by a robot (not shown). Next, an aqueous solution of hydrofluoric acid is supplied from the hydrofluoric acid supply means 6 through the pure water supply line 7, and the wafer 15 is immersed for a predetermined time. Next, a washing process is performed in which pure water is supplied from the pure water supply line 5 to drive out the hydrofluoric acid aqueous solution to the outside of the treatment tank 2. During this washing, an oxidizing gas such as oxygen or ozone gas is supplied from the oxidizing gas supply means 3 through the nozzle 11 into the closed chamber 1 for a predetermined time, and the inside of the closed chamber 1 is filled with the oxidizing gas. The oxidizing gas is dissolved in the pure water in the processing tank 2, and the surface of the silicon wafer 15 exposed by the hydrofluoric acid is slightly oxidized by the action of the oxidizing gas dissolved in the pure water to form a natural oxide film. This natural oxide film is a thin film having a thickness of 0.5 nm or less. Next, after supplying the oxidizing gas for a predetermined time, nitrogen gas is supplied from the nitrogen supply line 5 to replace the atmosphere in the closed chamber 1 with nitrogen. Thereby, the inside of the closed chamber 1 is in a state without oxygen. Then IP
A mixed gas of the IPA vapor and the nitrogen gas from the A vapor supply means 4 is supplied into the closed chamber 1 through the nozzle 11, and the inside of the closed chamber is filled with the IPA vapor and nitrogen. Next, the wafer 15 is lifted from the processing tank 2 and the wafer 1 is lifted.
5 Water droplets adhering to the surface are replaced by IPA vapor and drying is performed. By performing such a procedure, the formation of a watermark on the wafer surface is prevented, and the oxidizing gas, which is a feature of the present invention, is supplied into the closed chamber 1 to clean the wafer 15 immediately after the hydrofluoric acid treatment. The surface is oxidized in a trace amount to form a natural oxide film with a thickness of 0.5 nm or less. It has an excellent effect of suppressing impurities and foreign substances adhering to the back surface or edge of the wafer 15 from adhering to the front surface of the wafer 15 and reducing device characteristic deterioration and yield reduction. Metal impurities and foreign substances tend to adhere to pure silicon, but hardly adhere to the surface of a natural oxide film. Also, even if metal impurities once adhere to the silicon surface, a natural oxide film is formed between the silicon and the metal impurities when the silicon surface is oxidized. Chemical reaction is suppressed, and deterioration of device characteristics is reduced.

Embodiment 2 FIG. 3 and 4 show a second embodiment.
1 shows a schematic diagram of a cleaning apparatus and a flow of substrate processing. In the first embodiment, the oxidizing gas supply means 3 is provided in the nitrogen supply line 5, but in the second embodiment, the pure water supply line 7 is provided with the oxidizing gas mixing means 8, and the oxygen or ozone gas However, the difference is that oxidizing gas such as is mixed into pure water.
The operation will be described with reference to FIG. Nitrogen gas is supplied into the closed chamber 1 and pure water is supplied into the processing tank 2.
5 is moved and immersed in the processing tank 2. Next, a hydrofluoric acid aqueous solution is supplied to perform immersion treatment for a predetermined time. Next, pure water mixed with an oxidizing gas is supplied from the oxidizing gas mixing means 8 through the pure water supply line 7 into the processing tank 2 to be washed with water. The wafer surface exposed by the hydrofluoric acid in this process is oxidized in a trace amount by the action of the oxidizing gas dissolved in the pure water, and is 0.5 nm.
The following natural oxide film is formed. Next, as described in the first embodiment, the mixed gas of the IPA vapor and the nitrogen gas is supplied into the closed chamber 1, and the drying of the wafer 15 similar to that described in the first embodiment is performed. The atmosphere in the sealed chamber 1 is filled with nitrogen gas during a series of processing. In the second embodiment, by mixing an oxidizing gas such as oxygen or ozone gas into pure water, the pure surface of the wafer 15 after the hydrofluoric acid treatment is slightly oxidized to form a natural oxide film. Impurities contained in trace amounts of hydrofluoric acid, pure water, IPA, nitrogen gas, and the like used for cleaning the wafer 15, impurities adhering to the wafer 15, foreign substances, and the like are prevented from adhering to the wafer surface.

Embodiment 3 5 and 6 show a third embodiment.
1 shows a schematic diagram and a processing flow of the cleaning apparatus of FIG. The third embodiment differs from the second embodiment in that the oxidizing gas mixing means 8 is provided in the pure water supply line 7, but the hydrogen peroxide water supply means 9 is provided instead. Different. The operation will be described with reference to FIG. While supplying nitrogen gas in the closed chamber 1 and supplying pure water into the processing tank 2,
The wafer 15 is moved and immersed in the wafer processing tank 2. Next, a hydrofluoric acid aqueous solution is supplied and immersion treatment is performed for a predetermined time. Next, pure water is supplied, and a rinsing process is performed to drive the hydrofluoric acid aqueous solution out of the treatment tank 2. Next, a hydrogen peroxide solution is supplied from the hydrogen peroxide solution supply means 9 into the processing tank 2 through the pure water supply line 7, and the wafer 15 is immersed in the hydrogen peroxide solution for a predetermined time. Wafer 15 exposed by hydrofluoric acid in this step
Is slightly oxidized by the action of hydrogen peroxide solution, and 0.5n
m or less of a natural oxide film is formed. Next, a rinsing process for supplying pure water to drive out the hydrogen peroxide solution out of the treatment tank 2 is performed. Next, the same drying as described in the first embodiment is performed. The inside of the closed chamber 1 is an atmosphere filled with nitrogen gas during a series of processes. In the third embodiment, the pure surface of the wafer 15 immediately after the hydrofluoric acid treatment is slightly oxidized by a treatment with a hydrogen peroxide solution to form and protect a natural oxide film. A similar effect is achieved.

Embodiment 4 7 and 8 show a fourth embodiment.
1 shows a schematic diagram and a processing flow of the cleaning apparatus of FIG. The fourth embodiment is a modified application of the first embodiment. Pure water supply in which a closed chamber 1 has two processing tanks 2 and 2a and a first processing tank 2 has hydrofluoric acid supply means 6 is provided. The line 7 (first pure water supply line) is different in that another second processing tank 2a is provided with a second pure water supply line 7a which is another pure water supply line. The operation will be described with reference to FIG.
Nitrogen gas is flown into the closed chamber 1 and pure water is supplied to the first processing tank 2 to remove the wafer 15 from the first processing tank 2.
Move and immerse. Next, a hydrofluoric acid aqueous solution is supplied and immersion treatment is performed for a predetermined time. Next, the wafer 15 is lifted up from the first processing tank 2 and the second processing tank 2 supplying pure water.
a to be washed with water. From the first treatment tank 2 to the second
Before and after the wafer 15 is moved to the processing tank 2a, an oxidizing gas such as oxygen or ozone gas is supplied into the closed chamber 1 through the nozzle 11 for a predetermined time, and the closed chamber 1 is filled with the oxidizing gas. The surface of the wafer 15 exposed by the hydrofluoric acid is moved from the first processing tank 2 to the second processing tank 2a.
A small amount of oxygen is oxidized by the action of the oxidizing gas during transfer to
A natural oxide film of 5 nm or less is formed. Next, a nitrogen gas is supplied to replace the atmosphere in the closed chamber 1 with nitrogen.
Next, drying of wafer 15 is performed in the same manner as described in the first embodiment. Since the drying is in a nitrogen gas atmosphere, generation of a watermark can be prevented. In the fourth embodiment, the oxidizing gas is supplied into the closed chamber 1 and two treatment tanks are provided to separate the hydrofluoric acid treatment and the water washing treatment, so that the pure water of the wafer 15 immediately after the hydrofluoric acid treatment is obtained. Since the surface is slightly oxidized with an oxidizing gas to form and protect a natural oxide film, the same effects as described in the first and second embodiments can be obtained.

Embodiment 5 9 and 10 show a schematic diagram and a processing flow of the cleaning apparatus according to the fifth embodiment. The fifth embodiment is a modified application of the first embodiment, and is different from the first embodiment in that a drain line 10 for rapidly draining hydrofluoric acid in the treatment tank 2 is provided. The operation will be described with reference to FIG. Nitrogen gas is supplied into the closed chamber 1 and pure water is supplied into the processing tank 2, and the wafer 15 is moved and dipped into the processing tank 2. Next, a hydrofluoric acid aqueous solution is supplied and immersion treatment is performed for a predetermined time. Next, the hydrofluoric acid in the processing tank 2 is rapidly drained from the drain line 10, and then pure water is supplied to the processing tank 2 to wash the wafer 15. An oxidizing gas such as oxygen or ozone gas is supplied into the closed chamber 1 from the oxidizing gas supply means 9 through the nozzle 11 for a predetermined time before and after the drainage of hydrofluoric acid, and the closed chamber 1 is filled with the oxidizing gas. The surface of the wafer 15 exposed by the hydrofluoric acid during the rinsing and rinsing of the hydrofluoric acid in the processing tank 2 is slightly oxidized by the action of the oxidizing gas to form a natural oxide film of 0.5 nm or less. After the oxidizing gas is supplied for a predetermined time, a nitrogen gas is supplied to replace the atmosphere in the closed chamber 1 with nitrogen. Next, the wafer 15 is dried in the same manner as described above, but the generation of the watermark is similarly prevented. In the fifth embodiment, since the oxidizing gas is supplied into the closed chamber 1 and the hydrofluoric acid is rapidly drained from the processing tank 2, a natural oxide film can be quickly formed on the solid surface of the wafer 15. Thus, the wafer can be protected, and the same effects as described in the first and second embodiments can be obtained.

[0021]

The semiconductor substrate cleaning apparatus and the cleaning method using the same according to the present invention have the following effects because they are configured and processed as described above.

Since the nitrogen supply line provided with the oxidizing gas supply means is provided in the closed chamber, a natural oxide film can be formed on the wafer surface after the hydrofluoric acid treatment, so that impurities and foreign substances adhere to the wafer. To reduce device characteristics and yield.

Further, since a pure water supply line provided with an oxidizing gas mixing means is provided in the wafer processing tank, a natural oxide film can be formed on the wafer surface after the hydrofluoric acid treatment, and impurities and foreign substances can be formed on the wafer. Is suppressed, and a similar effect is achieved.

Further, since a pure water supply line provided with a hydrogen peroxide solution supply means is provided in the wafer processing tank, a natural oxide film can be formed on the wafer surface after hydrofluoric acid treatment. It works.

Further, a nitrogen supply line provided with an oxidizing gas supply means is provided in the closed chamber,
A second wafer processing tank is provided in the closed chamber, and after moving to the second wafer processing tank after the hydrofluoric acid treatment in the first wafer processing tank, a natural oxide film can be formed on the wafer surface during the water washing processing. The operation and effect of

Further, since a nitrogen supply line having an oxidizing gas supply means is provided in the closed chamber and a hydrofluoric acid drainage line is provided in the wafer processing tank, the drainage liquid after the hydrofluoric acid treatment can be quickly discharged. Thus, a natural oxide film can be quickly formed on the wafer surface, and the same operation and effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a cleaning device according to a first embodiment of the present invention.

FIG. 2 is a flow chart of substrate processing according to the first embodiment of the present invention.

FIG. 3 is a schematic view of a cleaning apparatus according to a second embodiment of the present invention.

FIG. 4 is a substrate processing flowchart showing Embodiment 2 of the present invention.

FIG. 5 is a schematic view of a cleaning apparatus according to a third embodiment of the present invention.

FIG. 6 is a substrate processing flow chart showing Embodiment 3 of the present invention.

FIG. 7 is a schematic diagram of a cleaning device according to a fourth embodiment of the present invention.

FIG. 8 is a flowchart of a substrate processing according to a fourth embodiment of the present invention.

FIG. 9 is a schematic view of a cleaning apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a substrate processing flow chart showing Embodiment 5 of the present invention.

FIG. 11 is a schematic view showing a conventional cleaning device.

FIG. 12 is a flowchart of a conventional substrate processing.

[Explanation of symbols]

1 closed chamber, 2, 2a wafer processing tank, 3 oxidizing gas supply means, 4 IPA vapor supply means, 5 nitrogen supply line, 6 hydrofluoric acid supply means, 7, 7a pure water supply line, 8 oxidizing gas mixing means, 9 Hydrogen peroxide water supply means, 10 drainage line, 11 nozzle, 12 exhaust port, 15 wafer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/306 D

Claims (11)

[Claims] A closed chamber; a wafer processing tank provided in the closed chamber; a nitrogen supply line provided in the closed chamber and provided with an oxidizing gas supply unit and an IPA vapor supply unit; And a pure water supply line provided with a hydrofluoric acid supply means. 2. A closed chamber, a wafer processing tank provided in the closed chamber, a nitrogen supply line provided in the closed chamber with IPA vapor supply means, and a hydrofluoric acid supply means provided in the wafer processing tank. And a pure water supply line having an oxidizing gas mixing means. 3. A closed chamber, a wafer processing tank provided in the closed chamber, a nitrogen supply line provided in the closed chamber with IPA vapor supply means, and a hydrofluoric acid supply means provided in the wafer processing tank. And a pure water supply line provided with a hydrogen peroxide solution supply means. 4. A nitrogen supply line comprising a closed chamber, first and second wafer processing tanks provided in the closed chamber, and an oxidizing gas supply unit and an IPA vapor supply unit provided in the closed chamber. A first pure water supply line provided in the first wafer processing tank and provided with hydrofluoric acid supply means; and a second pure water supply line provided in the second wafer processing tank. An apparatus for cleaning a semiconductor substrate, comprising: 5. A closed chamber, a wafer processing tank provided in the closed chamber, a nitrogen supply line provided in the closed chamber including oxidizing gas supply means and IPA vapor supply means, and the wafer processing tank. And a pure water supply line provided with hydrofluoric acid supply means, and a liquid drain line is provided in the wafer processing tank. 6. The cleaning device according to claim 1, wherein
A method for cleaning a semiconductor substrate, comprising the following steps. (1) A step of supplying pure water to the processing tank. (2) A step of supplying nitrogen gas into the closed chamber and moving and dipping the wafer into the processing tank. (3) a step of supplying a hydrofluoric acid aqueous solution to the treatment tank and immersing the wafer for a predetermined time; (4) A step of supplying pure water to the processing tank, flushing the hydrofluoric acid aqueous solution out of the processing tank, washing the wafer with water, and supplying an oxidizing gas into the closed chamber for a predetermined time to form an oxide film on the wafer surface. (5) replacing the inside of the closed chamber with nitrogen gas. (6) A step of lifting the wafer from the processing tank and supplying a mixed gas of IPA vapor and nitrogen gas into the closed chamber. 7. The cleaning device according to claim 2, wherein
A method for cleaning a semiconductor substrate, comprising the following steps. (1) A step of supplying pure water to the processing tank. (2) A step of supplying nitrogen gas into the closed chamber and moving and dipping the wafer into the processing tank. (3) a step of supplying a hydrofluoric acid aqueous solution to the treatment tank and immersing the wafer for a predetermined time; (4) A step of supplying pure water mixed with an oxidizing gas to the processing tank to form an oxide film on the wafer surface. (5) A step of lifting the wafer from the processing tank and supplying a mixed gas of IPA vapor and nitrogen gas into the closed chamber. 8. Use of the cleaning device according to claim 3,
A method for cleaning a semiconductor substrate, comprising the following steps. (1) A step of supplying pure water to the processing tank. (2) A step of supplying nitrogen gas into the closed chamber and moving and dipping the wafer into the processing tank. (3) a step of supplying a hydrofluoric acid aqueous solution to the treatment tank and immersing the wafer for a predetermined time; (4) A step of supplying pure water to the processing tank, flushing the hydrofluoric acid aqueous solution out of the processing tank, and washing the wafer with water. (5) a step of supplying an aqueous hydrogen peroxide solution to the treatment tank and immersing the wafer for a predetermined time to form an oxide film on the wafer surface; (6) A step of supplying pure water to the treatment tank and driving out the hydrogen peroxide solution out of the treatment tank. (7) A step of lifting the wafer from the processing tank and supplying a mixed gas of IPA vapor and nitrogen gas into the closed chamber. 9. A cleaning device according to claim 4, wherein
A method for cleaning a semiconductor substrate, comprising the following steps. (1) A step of supplying pure water to the first processing tank. (2) A step of supplying nitrogen gas into the closed chamber and moving and dipping the wafer into the first processing tank. (3) a step of supplying an aqueous solution of hydrofluoric acid to the first processing tank and immersing the wafer for a predetermined time; (4) Supplying an oxidizing gas into the closed chamber for a predetermined time, transferring the wafer from the first processing tank to a second processing tank supplying pure water, and forming an oxide film on the wafer surface . (5) replacing the inside of the closed chamber with nitrogen gas. (6) A step of lifting the wafer from the second processing tank and supplying a mixed gas of IPA vapor and nitrogen gas into the closed chamber. 10. A method for cleaning a semiconductor substrate using the cleaning apparatus according to claim 5, comprising the following steps. (1) A step of supplying pure water to the processing tank. (2) A step of supplying nitrogen gas into the closed chamber and moving and dipping the wafer into the processing tank. (3) a step of supplying a hydrofluoric acid aqueous solution to the treatment tank and immersing the wafer for a predetermined time; (4) A step of supplying an oxidizing gas into the closed chamber for a predetermined time and draining hydrofluoric acid in the treatment tank from a drain line. (5) A step of supplying pure water to the treatment tank, washing the wafer with water, and forming an oxide film on the wafer surface. (6) A step of replacing the inside of the closed chamber with nitrogen gas. (7) A step of lifting the wafer from the processing tank and supplying a mixed gas of IPA vapor and nitrogen gas into the closed chamber. 11. The method according to claim 6, wherein the thickness of the oxide film on the surface of the wafer is 0.5 nm or less.
13. The method for cleaning a semiconductor substrate according to the above item.