JP2009283725A - Silicon wafer processing method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the quality of wafers as consistent as possible by performing an oxide film removal processing on the surface of a silicon wafer, specifically, performing efficient removal of an oxide film from the inner wall of opened defects which is difficult by wet cleaning with hydrofluoric acid water, etc. and by controlling the oxide film removal rate during the oxide film removal processing process. <P>SOLUTION: A processing method is provided, wherein a mixed gas containing hydrogen fluoride and water vapor is produced and the produced mixed gas is sprayed against a silicon wafer to perform a processing such as removal of an oxide film. In this method, the ratio of hydrogen fluoride to water vapor can be changed in conformity with the oxide film to be removed. Also, a mixed gas generation apparatus is provided for this purpose and a processing apparatus is provided for performing an oxide film removal processing which includes the mixed gas generation apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for processing an oxide film on a silicon wafer. More specifically, the present invention relates to a processing method and apparatus using a mixed gas containing wet hydrogen fluoride.

A silicon wafer, for example, an oxide film on the surface of the silicon wafer is useful for protecting the main body during handling, but must be removed in a subsequent process such as epitaxial growth. Therefore, the substrate is used as a substrate after being cleaned with hydrofluoric acid water or the like to remove the oxide film (for example, Patent Document 1). On the other hand, when a silicon oxide film is removed from the surface of a substrate using hydrofluoric acid vapor, a method for preventing the formation of colloidal silica accompanying decomposition and removal of the silicon oxide film is disclosed. A technology is disclosed in which a hydrophobizing agent such as hexamethyldisilazane is supplied to the surface of the substrate to hydrophobize the surface of the substrate to prevent excessive adsorption of hydrogen fluoride and water vapor on the surface of the substrate. (For example, patent document 2).
JP 2006-179831 A JP-A-5-326464

  However, with wet cleaning such as hydrofluoric acid, it is difficult to efficiently remove the inner wall oxide film having the open defects. Further, in cleaning with hydrofluoric acid vapor, processing is performed in a chamber containing hydrofluoric acid vapor having a constant concentration, so that the oxide film removal rate cannot be controlled, resulting in variations in wafer quality.

  In view of the problems as described above, in the present invention, a mixed gas containing hydrogen fluoride and water vapor is generated, and this mixed gas is injected onto a silicon wafer to perform processing such as removal of an oxide film, Provided is a processing method characterized in that the ratio of hydrogen fluoride to water vapor can be changed according to the oxide film to be removed. In addition, a mixed gas generator for the same and a processing apparatus for oxide film processing including the generator are provided.

More specifically, the following can be provided.
(1) A processing method for processing an oxide film of a silicon wafer, including a generation step of generating a mixed gas containing hydrogen fluoride and water vapor, and an injection step of injecting the mixed gas onto a silicon wafer, wherein the generation In the process, it is possible to provide a processing method characterized in that the ratio of hydrogen fluoride to water vapor can be changed according to the oxide film. Here, processing the oxide film of the silicon wafer may include changing the oxide film to a preferable one in accordance with a post process or required quality. Changing to this preferred one can include simply removing the oxide film and can include reducing the oxide film to a different property. Also, matching the ratio to the oxide film may mean complying with the chemical and / or physical properties of the oxide film. For example, it may correspond to properties such as the degree of oxidation of the oxide film and the degree of porosity of the oxide film.

(2) The processing method according to (1) above, wherein the generation step includes a step of bubbling a non-oxidizing gas in hydrofluoric acid water.

  Here, the non-oxidizing gas can include at least one or more of inert gases such as argon and nitrogen, and reducing gases such as hydrogen. Nitrogen is preferred because of its availability.

(3) The method according to (2), wherein the ratio of hydrogen fluoride to water vapor in the mixed gas is changed by adjusting the flow rate and / or temperature of the non-oxidizing gas. Can provide.

(4) A container capable of storing hydrofluoric acid water having a predetermined concentration, a supply pipe for supplying a non-oxidizing gas to be bubbled into the hydrofluoric acid water stored in the container, and the non-oxidation sent to the supply pipe It is possible to provide a wet hydrogen fluoride gas generator including an adjustment device that adjusts the flow rate and / or temperature of a sex gas and a control device that controls the adjustment device as necessary. Here, the predetermined concentration is a concentration of hydrofluoric acid water that can generate a mixed gas containing water vapor and hydrogen fluoride sufficient to perform the treatment. Since hydrogen fluoride can be dissolved almost infinitely in water, the upper limit of the concentration of hydrogen fluoride may be as high as technically possible. For example, 46-50% hydrofluoric acid water is generally commercially available and can contain such concentrations. The lower limit of the predetermined concentration of the hydrofluoric acid water to be stored is not particularly limited as long as a mixed gas containing hydrogen fluoride having a preferable concentration is generated, but generally 10% or more is desirable. 20% or more is more preferable, and 40% or more is more preferable. The container is preferably a sealable container made of a material that can withstand hydrofluoric acid. The stored hydrofluoric acid water includes a hydrofluoric acid aqueous solution having a concentration higher than the concentration of the hydrofluoric acid stored and the hydrofluoric acid aqueous solution having a concentration lower than the concentration of the hydrofluoric acid stored. Or it is preferable to supply deionized water from piping (a tube is included. The following is same). In order to prevent contamination, it is preferable not to contact unnecessary piping with the hydrofluoric acid water stored. The container preferably includes a gas-liquid separation tank. The control device can adjust the flow rate of the non-oxidizing gas, for example, a flow control device such as a mass flow controller, and / or the temperature of the non-oxidizing gas, for example, a heater with a temperature controller. Such a temperature control device may be included. Wet hydrogen fluoride gas may mean hydrofluoric acid water vapor. In particular, steam (which may contain nitrogen or the like) generated by bubbling hydrofluoric acid water with nitrogen or the like can be included.

(5) A silicon wafer processing apparatus comprising the generator according to (4) above and a nozzle for injecting wet hydrogen fluoride gas generated by the apparatus onto the silicon wafer can be provided.

(6) In the epitaxial wafer manufacturing method for growing an epitaxial layer on a silicon wafer substrate, the silicon wafer substrate is processed by the processing method according to any one of (1) to (3), and the processed And a step of growing an epitaxial layer on the silicon wafer substrate.

  In the above-described method or apparatus, in the cleaning process of the semiconductor silicon wafer, the inner wall oxide film of COP existing on the wafer surface that may cause defects in the epitaxial growth layer is efficiently removed in the cleaning before the process for epitaxial growth. For this reason, steam of hydrofluoric acid water is used instead of hydrofluoric acid water. In such a hydrofluoric acid water vapor generator, for example, an aqueous solution of hydrogen fluoride (50 wt%) is stored in a tank and nitrogen is bubbled into the tank to generate vapor and blown to the wafer surface. Can be attached. At this time, the etching rate of the oxide film can be controlled by installing a gas concentration meter in the pipe (tube) through which the generated hydrofluoric acid water vapor flows and adjusting the abundance ratio of hydrogen fluoride and water vapor in the generated vapor. I found.

  Here, bubbling refers to the formation of a large number of bubbles by releasing non-oxidizing gas in hydrofluoric acid water. For example, a porous material such as a membrane filter is placed in hydrofluoric acid water, and the inside of the membrane filter By releasing the non-oxidizing gas, a large number of fine bubbles can be formed. Further, the chemical reaction formula in the etching of silicon oxide by the hydrofluoric acid water vapor is as follows.

The presence of both hydrogen fluoride and water (including water vapor) can generate etchant HF ₂ ^{− and} etch SiO ₂ . At this time, for example, the following three can be considered as parameters capable of adjusting the abundance ratio of hydrogen fluoride and water vapor in hydrofluoric acid water vapor.
(A) Concentration (concentration of hydrogen fluoride in hydrofluoric acid water)
(B) Flow rate (Non-oxidizing gas flow rate)
(C) Temperature (temperature of non-oxidizing gas)
The etching rate can be controlled by adjusting the above three parameters and controlling the ratio of HF / H ₂ O. In this way, for example, a constant etching rate can always be controlled. In addition, it becomes possible to produce a wafer with stable quality.

Thus, in the present invention, a mixed gas of hydrogen fluoride and water vapor can be used as the processing gas, and a special state such as plasma or the like is unnecessary. Further, the processing can be performed at normal temperature and normal pressure, and it is considered possible to detect the etching end point while monitoring the Si film thickness or the SiO ₂ film thickness. This is because it is a process in the gas phase. Here, hydrofluoric acid water vapor (wet hydrogen fluoride gas), which is a mixed gas containing hydrogen fluoride and water vapor, has a high ability to dissolve the SiO ₂ film. In addition, it is possible to measure the film thickness with an optical / infrared sensor or the like while performing an etching process to detect the end point.

  As described above, since silicon wafers can be processed using wet hydrogen fluoride gas with different mixing ratios, the optimum processing (for example, the fastest processing) is performed according to the type of the target oxide film. Can do. Since this process is performed in the gas phase, the silicon wafer surface can be monitored. That is, the ratio of hydrogen fluoride and water vapor can be changed based on the monitor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following description is made for explaining the embodiments of the present invention, and the present invention is limited to these embodiments. is not. The same or the same type of elements are denoted by the same or related symbols, and redundant description is omitted.

FIG. 1 is a schematic view of a silicon wafer processing apparatus 10 according to an embodiment of the present invention. The silicon wafer processing apparatus 10 includes a nitrogen supply unit that supplies nitrogen gas, a mixed gas generation unit that generates a mixed gas of hydrogen fluoride and water vapor (wet hydrogen fluoride gas), and an HF / H ₂ O concentration ratio. And a processing section for injecting a mixed gas applied to the silicon wafer. The nitrogen supply unit includes a nitrogen supply device that can supply nitrogen such as a nitrogen cylinder (not shown) at a predetermined pressure, a mass flow control 38 that is connected to the supply device and can adjust a nitrogen flow rate, and a nitrogen gas whose flow rate is adjusted. It comprises a heater 36 for heating and a pipe (or tube) 18.

  The mixed gas generator is mainly composed of a sealed tank into which the pipe 18 is introduced. The hermetically sealed tank includes a gas-liquid separation tank 12a on the upper side and a bubbling tank 12b to which contents can be moved in and out through a communication path narrowed (constricted) on the lower side. A pipe 28 capable of supplying hydrogen fluoride or concentrated hydrofluoric acid water is connected to the bottom of the bubbling tank 12b together with a valve (not shown), and a pipe 30 capable of supplying deionized water (DIW) is not shown. Connected together. From these pipes 28 and 30, hydrogen fluoride (or concentrated hydrofluoric acid water) and water are supplied from the bottom of the bubbling tank 12 b, filling the bubbling tank as hydrofluoric acid water, exceeding the Low level 26, and Up to the constricted communication passage (Middle level 26), it is accumulated. The gas-liquid separation tank 12a above it is designed to calm the mist, and the hydrofluoric acid water is not raised up to the High level 26. A drain pipe 34 is provided at the bottom of the bubbling tank 12b together with a valve (not shown). Similarly, the above-described nitrogen gas supply pipe 18 is connected to the bottom. When a valve (not shown) is opened, nitrogen gas whose flow rate is adjusted and heated to a predetermined temperature is supplied from the bottom through a porous body (not shown), and the hydrofluoric acid water stored in the bubbling tank 12b is bubbled. . The concentration of hydrogen fluoride in the hydrofluoric acid water is measured by the HF densitometer 25 by analyzing the hydrofluoric acid water sampled from above and sent through the pipe 27. Thus, there is no piping in the bubbling tank 12b, and contamination of hydrofluoric acid water resulting from contact with the piping can be effectively prevented.

  As described above, the nitrogen gas supplied from the bottom and bubbling hydrofluoric acid water in the bubbling tank 12b forms a gas-phase bubble 20 containing vapor of hydrogen fluoride water, passes through the constricted communication passage described above, It comes out of the hydrofluoric acid water and rises to the gas-liquid separation tank 12a. In the gas-liquid separation tank 12a, nitrogen gas (mixed gas) containing hydrogen fluoride and water vapor and liquid components such as water are separated and discharged to the pipe 24 through the discharge port provided in the ceiling. The

The pipe 24 is introduced into the mist trap 23 so that the mist is trapped and does not reach the processing chamber. A drain pipe is provided at the bottom of the mist trap. When the valve 31 is opened, the hydrofluoric acid mist accumulated in the bubbling tank 12b is returned. Thereby, effective use of hydrofluoric acid is achieved. The mixed gas is discharged from the mist trap 23 through the pipe 29. The pipe 29 is bifurcated and includes air valves 40 and 46, respectively. The monitor unit is composed of a pipe 44 on the air valve 40 side and a gas concentration meter 42 using FTIR, measures the HF / H ₂ O concentration ratio of the generated mixed gas, and the measured mixed gas is discharged out of the system. Is done.

  The processing unit mainly includes a pipe 48 on the air valve 46 side, a nozzle 50 that blows a mixed gas onto the silicon wafer 52, and a rotary stage 56 that rotationally drives the silicon wafer 52. The nozzle 50 has a pipe that extends horizontally immediately above the silicon wafer 52 as a main component, and is provided with holes that open downward at a plurality of locations in the pipe. The mixed gas is injected into the conical shape 54 from the hole toward the silicon wafer 52. The silicon wafer 52 is fixed to the rotary stage 56 by the chuck jig 58 and rotated. In this embodiment, the nozzle 50 is not driven, but may be reciprocated horizontally.

In the present embodiment, a gas concentration meter 42 (FTIR in the present embodiment) is provided in the pipe 44, the concentrations of HF and H ₂ O are confirmed, and the abundance ratio of HF / H ₂ O is controlled within a certain range. The silicon wafer 52 is processed. The specific procedure is summarized as follows.
(I) A concentrated stock solution of hydrogen fluoride water and pure water are placed in a sealed tank and mixed. At this time, the concentration of hydrogen fluoride is measured with a liquid concentration meter installed, and is prepared into a desired concentration of hydrogen fluoride water (hydrofluoric acid water).
(II) Next, a predetermined amount of nitrogen supplied from the nitrogen supply device is bubbled into the hydrogen fluoride water in the bubbling tank 12b. For example, a mixed gas of hydrogen fluoride, water vapor, and nitrogen is more easily generated by bubbling from a porous body.
(III) The flow rate of nitrogen is adjusted by the mass flow controller 38 while checking the HF / H ₂ O ratio by the gas concentration meter 42, and the temperature of the supply nitrogen is adjusted by controlling the output of the heater 36. For example, when the nitrogen flow rate is increased, the content of hydrogen fluoride increases and the content of water vapor decreases. Therefore, the ratio of HF / H ₂ O increases. Further, when the temperature is raised, the contents of hydrogen fluoride and water vapor increase, but the ratio of HF / H ₂ O is relative, and therefore changes according to the conditions at that time. During this time, since the air valve 46 is closed, the mixed gas is not supplied to the processing section.
(IV) After confirming that the desired HF / H ₂ O ratio is obtained, the air valve 46 is opened, and the mixed gas is injected from the nozzle 50 onto the silicon wafer 52 to start processing. At this time, the rotation stage 56 starts to rotate at the same time so that the processing proceeds uniformly.

FIG. 2 is a graph showing the relationship between each gas concentration (ppm) and the etching rate when the nitrogen flow rate is changed from 2 to 40 NL / min in the apparatus of FIG. Mixed gas generation was performed at 25 ° C., and the water temperature and gas temperature were also 25 ° C. The heater 36 remained off. The concentration of hydrofluoric acid water stored in the tank 12 was 50% by weight. Under these conditions, a mixed gas was generated, and the concentration of hydrogen fluoride and water vapor was measured with a gas concentration meter 42 using FTIR. For hydrogen fluoride, the peak at 4038.4 cm ⁻¹ was used, and for water vapor, the peak at 1576.0 cm ⁻¹ was used, and the respective concentrations were determined from the respective peak heights. Further, after the measurement by the gas concentration meter 42, the etching rate of the natural oxide film on the silicon wafer was actually measured. As can be seen from this graph, as the flow rate increases, the concentration of water vapor decreases and the concentration of hydrogen fluoride increases. That is, the HF / H ₂ O ratio increases. In other words, it is effective to increase (decrease) the nitrogen flow rate in order to increase (decrease) the HF / H ₂ O ratio. On the other hand, the etching rate shows the maximum when the nitrogen flow rate is 20 NL / min, and drops sharply at 40 NL / min.

Next, the flow rate of nitrogen was fixed at 20 NL / min, and the influence of the HF / H ₂ O ratio on the etching rate was examined in more detail. At this time, the HF / H ₂ O ratio can be changed by changing the hydrogen fluoride concentration of the stored hydrofluoric acid water or by changing the temperature. For example, in this embodiment, if the concentration of hydrogen fluoride in hydrofluoric acid water is increased (lower), the HF / H ₂ O ratio is increased (lower). Further, when the temperature is increased (lower), the HF / H ₂ O ratio is increased (lower). The result is shown in FIG. The vertical axis in FIG. 3 represents the etching rate, and represents the etching rate of the oxide film by CVD, the natural oxide film, and the thermal oxide film by heat treatment on the silicon wafer, respectively. The horizontal axis represents the HF / H ₂ O ratio. The black square is the etching rate of the oxide film by CVD, the white square is the etching rate of the natural oxide film, and the white circle is the etching rate of the thermal oxide film. The etching rate for these oxide films was highest for the CVD film, followed by that for the thermal oxide film, and the rate of the natural oxide film was the lowest. This is considered to be related to the density of the oxide film. The CVD film is porous, and the thermal oxide film is also less dense than the natural oxide film. In any film type, the etching rate showed the maximum when the HF / H ₂ O ratio was a predetermined value between 0 and 1.5. The etching rate for the CVD film was high in the range of 0.25 to 1, higher in the range of 0.5 to 0.75, and maximum at about 0.65 by interpolation. Further, the etching rate of the thermal oxide film was high in the range of 0.25 to 1.25, higher in the range of 0.5 to 0.8, and maximum at about 0.73 by interpolation. The etching rate of the natural oxide film was high in the range of 0.25 to 1.25, higher in the range of 0.5 to 1, and maximum at about 0.75 by interpolation. From this, it was found that the HF / H ₂ O ratio (corresponding to the volume ratio) that maximizes the etching rate is about 0.65 to about 0.75, and an environment with a little water vapor is preferable. That is, the HF / H ₂ O ratio is high according to the degree of density of the oxide film. Thus, it can be seen that there is an optimum (fastest) etching rate according to the film quality of the oxide film. For this reason, when the film quality is known in advance, an optimum rate is obtained by changing the HF / H ₂ O ratio while measuring the etching rate using a mixed gas of a ratio appropriate to the film quality or when the film quality is not known. Can be found.

FIG. 4 is a block diagram showing a control system of the etching apparatus 100 according to the embodiment of the present invention. The disk rotation driving device 102 that rotationally drives the table on which the silicon wafer is placed and the nozzle driving device 110 that is added as necessary can ensure uniform contact of the mixed gas on the silicon wafer. Is controlled by the control device 106. The control device 106 is provided with an input device / display device 108 for inputting an initial value or the like and confirming the input value. The densitometer 104 for measuring the HF / H ₂ O ratio is also controlled by the control device 106, controls the flow rate of nitrogen from the nitrogen supply device 112 according to a predetermined program, and stores hydrogen fluoride of hydrofluoric acid water. The concentration is adjusted by a hydrofluoric acid concentration adjusting device 114 that detects and adjusts the concentration of water. Furthermore, the temperature of nitrogen gas is adjusted by controlling a regulator 116 that regulates the output of the heater.

  FIG. 5 is a graph showing the temperature change of the saturated water vapor pressure. It can be seen that as the temperature rises, the saturated water vapor pressure increases and more water vapor is present in the gas mixture. Incidentally, hydrogen fluoride itself has a boiling point of 19.54 ° C., and the vapor pressure at 25 ° C. is 122 kPa. On the other hand, in the 55% hydrofluoric acid aqueous solution, the specific gravity is 1.20, and the vapor pressure at 26.7 ° C. is 4.932 kPa. Therefore, as shown in FIG. 2, the ratio of hydrogen fluoride and water vapor in the mixed gas is sufficiently lower than their saturation, so that the concentration ratio can be easily changed.

FIG. 6 is a flowchart illustrating a processing method according to an embodiment of the present invention. First, initial values such as the nitrogen flow rate, temperature, and concentration of hydrofluoric acid water are input (S10). Next, the gas concentration meter 42 is turned on to start monitoring (S12). Then, supply of nitrogen gas is started, nitrogen gas is allowed to flow at a predetermined flow rate by the mass controller 38 (S14), and the output of the heater 36 is adjusted according to the initial setting. Thereby, bubbling is started and the measurement result of the gas concentration meter 42 is monitored as needed. For example, when an end signal such as completion of a predetermined amount of etching is received (S16, Yes), the process ends. If it does not enter (S16, No), it is determined whether the HF / H ₂ O ratio is optimal. If it is optimal (S18, Yes), the program is returned to the end signal input waiting routine. If not optimal (S18, No), at least one of the nitrogen flow rate, temperature, and hydrofluoric acid concentration is changed (S22), and the process is returned to the nitrogen gas supply routine. As described above, an optimum HF / H ₂ O ratio can be selected according to the film quality to be processed and according to the etching progress in the processing step.

  FIG. 7 shows an example in which such an oxide film processing apparatus or method is applied to an epitaxial substrate. In an epitaxial substrate, it is known that an internal oxide film of an open COP causes a stacking fault in an epitaxial layer grown on the surface. For this reason, it is preferable to remove such an internal oxide film, but it is not always easy to allow a liquid such as hydrofluoric acid water to enter the small opening. This is probably because the surface tension of the aqueous solution is high and the opening is covered with a water film, so that the aqueous solution cannot enter further due to the pressure in the air holes. For this reason, treatment in a gas phase such as hydrogen fluoride vapor is preferred. This is because the film does not block the opening because of the gas phase, and the diffusion rate of the gas is high. Therefore, the treatment in the gas phase of the present invention is desirable.

As shown in FIG. 7, an oxide film is formed on the inner wall of the groove-shaped COP formed on the surface of the wafer substrate W. Here, when the hydrofluoric acid (hydrogen fluoride) vapor is cleaned by the treatment method of the present invention, the oxide film is efficiently removed. Then, after this treatment, an epitaxial layer Epi is formed on the surface of the wafer substrate W. In forming the epitaxial layer Epi, first, heat treatment is performed in the presence of hydrogen to completely shrink the COP (H ₂ Bake treatment), and then the epitaxial layer Epi is formed using a normal epitaxial layer growth apparatus. The formation method of the epitaxial layer Epi is not particularly limited, and various methods such as a hydrogen reduction method, a thermal decomposition method, a metal organic chemical vapor deposition method (MOCVD method), a molecular beam epitaxial method (MBE method) can be adopted. . As described above, when the surface of the wafer substrate W is cleaned with hydrofluoric acid by the processing of the present invention, the oxide film inside the COP formed on the surface of the wafer substrate W is sufficiently removed, so that no stacking fault occurs. The production yield of the epitaxial silicon wafer substrate can be greatly improved.

It is the schematic of the processing apparatus of the Example of this invention. 2 is a graph showing a relationship between a nitrogen flow rate and an etching rate in the processing apparatus of FIG. 1. ₂ is a graph showing a relationship between an HF / H ₂ O ratio and an etching rate in the processing apparatus of FIG. 1. It is a block diagram which shows the control system of the etching apparatus which concerns on the Example of this invention. It is a graph which shows the temperature change of the vapor pressure of water. It is a flowchart which shows the processing method which concerns on the Example of this invention. It is the example which applied the processing method of the Example of this invention to the epitaxial substrate process.

Explanation of symbols

10, 100 Processing device 12 Sealed tank 25 HF concentration meter 42 Gas concentration meter 50 Nozzle 52 Silicon wafer 104 HF / H ₂ O ratio measuring device 106 Control device 116 Heater adjuster

Claims (6)

A production process for producing a mixed gas containing hydrogen fluoride and water vapor;
An injection step of injecting the mixed gas onto a silicon wafer, and a processing method for processing an oxide film of the silicon wafer,
The generation step includes
Generating the mixed gas from hydrofluoric acid water and a non-oxidizing gas;
Adjusting the flow rate and / or temperature of the non-oxidizing gas, if necessary,
A processing method characterized in that the ratio of hydrogen fluoride to water vapor can be changed according to the oxide film.   The processing method according to claim 1, wherein the generation step includes a step of bubbling a non-oxidizing gas in hydrofluoric acid water.   The processing method according to claim 2, wherein the ratio of hydrogen fluoride to water vapor in the mixed gas is changed by adjusting a flow rate and / or temperature of the non-oxidizing gas. A container capable of storing hydrofluoric acid water of a predetermined concentration;
A supply pipe for supplying a non-oxidizing gas to be bubbled into the hydrofluoric acid water stored in the container;
An adjusting device for adjusting the flow rate and / or temperature of the non-oxidizing gas sent to the supply pipe;
A wet hydrogen fluoride gas generator comprising: a control device for controlling the adjusting device as required. A generator according to claim 4;
A silicon wafer processing apparatus, comprising: a nozzle for injecting wet hydrogen fluoride gas generated by the apparatus onto the silicon wafer. In an epitaxial wafer manufacturing method for growing an epitaxial layer on a silicon wafer substrate,
A step of processing the silicon wafer substrate by the processing method according to claim 1;
And a step of growing an epitaxial layer on the treated silicon wafer substrate.

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