JP4361179B2 - Ozone treatment apparatus and ozone treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ozone treatment apparatus and an ozone treatment method, and more particularly to an ozone treatment apparatus and an ozone treatment method for performing ozone treatment on an object to be treated, for example, a semiconductor wafer.
[0002]
[Prior art]
In a semiconductor device manufacturing process, for example, a film forming process or an ashing process, an oxidation process using ozone is performed. For example, in the film forming process, a thermal oxidation process using ozone is performed using a heat treatment apparatus 51 as shown in FIG. 2 to form a silicon oxide film on an object to be processed such as a semiconductor wafer. Formation of the silicon oxide film using the heat treatment apparatus 51 shown in FIG. 2 is performed as follows.
[0003]
First, the reaction tube 52 having a double tube structure including the inner tube 52 a and the outer tube 52 b is heated to a predetermined temperature by the heater 53. Next, a wafer boat 55 accommodating a plurality of semiconductor wafers 54 is loaded into the reaction tube 52 (inner tube 52a). Subsequently, the gas in the reaction tube 52 is discharged from the exhaust port 56, and the inside of the reaction tube 52 is reduced to a predetermined pressure. When the inside of the reaction tube 52 is depressurized to a predetermined pressure, ozone is supplied from the gas supply tube 57 into the inner tube 52a. The ozone causes an oxidation reaction on the surface of the semiconductor wafer 54, thereby forming a silicon oxide film on the surface of the semiconductor wafer 54.
[0004]
In such an oxidation process using ozone, it is necessary to perform a uniform process on the entire surface of the object to be processed. For example, in the silicon oxide film forming process, it is necessary to form a silicon oxide film having a uniform thickness on the semiconductor wafer 54. Generally, in order to improve the uniformity of the silicon oxide film, it is preferable that the pressure in the reaction tube 52 be low.
[0005]
[Problems to be solved by the invention]
However, in order to reduce the pressure in the reaction tube 52, it is necessary to reduce the flow rate of ozone supplied into the reaction tube 52, which reduces the amount of ozone to be processed, and the effect of ozone treatment. There was a problem that could not be obtained.
[0006]
When the flow rate of ozone is increased in order to obtain the effect of the ozone treatment, there is a problem that the pressure variation in the reaction tube 52 becomes large and the pressure in the reaction tube 52 cannot be maintained at a low pressure.
[0007]
Further, in order to thermally oxidize the surface of the semiconductor wafer 54 using ozone, it is necessary to supply ozone to the semiconductor wafer 54 while maintaining the active state of ozone. In order to maintain the active state of ozone, for example, it is necessary to supply the semiconductor wafer 54 with ozone maintained at a low pressure. However, even if the inside of the reaction tube 52 is maintained at a low pressure, the inside of the gas supply tube 57 is likely to be at a higher pressure than the inside of the reaction tube 52, and ozone activity may be lost in the gas supply tube 57.
[0008]
The present invention has been made in view of the above problems, and provides an ozone treatment apparatus and an ozone treatment method that can increase the flow rate of ozone and perform uniform ozone treatment on the entire surface of an object to be treated. For the purpose.
Another object of the present invention is to provide an ozone treatment apparatus and an ozone treatment method capable of increasing the flow rate of ozone and maintaining the pressure in the reaction tube at a low pressure.
Furthermore, an object of this invention is to provide the ozone treatment apparatus and ozone treatment method which can maintain the active state of ozone.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an ozone treatment apparatus according to the first aspect of the present invention provides:
An ozone treatment apparatus for treating an object to be treated with ozone,
Wherein the processing region of the workpiece to ozone treatment, and one side of the first non-processing region of the processing region, and the other side of the second non-processing region of the processing region, wherein the first non-processing region and A processing chamber having a third non-processing area leading to the second non-processing area ;
The tip is inserted into the processing chamber so as to be located in the first non -processing area, and reaches the second non -processing area from the first non-processing area through the third non-processing area. And at least one ozone supply pipe for supplying ozone into the processing chamber;
Ozone supply means connected to the ozone supply pipe;
An exhaust port that is provided in the first non-processing region and exhausts the gas in the processing chamber;
An exhaust means connected to the exhaust port and supplying ozone that has reached the second non-processing region to the processing region by exhausting the gas in the processing chamber;
It is characterized by comprising.
[0011]
The first non-treated areas, for example, located below the processing chamber.
The processing in-room, for example, the ozone supply pipe is kicked one set, in the first non-processing region and the ozone supply pipe and the exhaust port that is arranged to face.
[0012]
The ozone supply pipe, for example, have a ozone introducing part that the tip portion is directed are bent to face the direction of the third untreated area to the third non-processing region, before Symbol ozone introduction part Is formed to be 1 to 100 times the inner diameter of the ozone introduction portion .
The tip portion of the ozone supply pipe is bent upward, for example.
[0013]
Wherein the ozone supply means, for example, have a ozone generator, which is composed of a plasma generator, ozone product gas supply pipe for supplying the oxygen gas and nitrogen gas is connected before Symbol ozone generator.
[0014]
Maintains the pre-Symbol processing chamber heated and under a reduced pressure atmosphere, said workpiece is thermally oxidized by ozone treatment, it may be composed of a heat treatment apparatus for forming a thin film on該被processed.
[0015]
The ozone treatment method according to the second aspect of the present invention is as follows.
An ozone treatment method for treating an object to be treated with ozone,
From the ozone supply pipe arranged so that the tip is located in the first non-processing area on one side of the processing area of the processing chamber having the processing area for ozone-treating the object to be processed, the first non-processing via the third non-processing region leading to region and the other side a second non-processing region of the processing region, supplies ozone to reach the second non-processing region,
By exhausting the gas in the processing chamber from an exhaust port provided in the first non-processing region, ozone that has reached the second non- processing region is supplied to the processing region.
[0017]
The ozone supplied from the ozone supply pipe may be supplied into the processing chamber at a temperature and pressure that can flow as a high-speed viscous flow and maintain the active state of ozone .
[0018]
Maintaining the processing chamber at a predetermined temperature and a predetermined pressure;
A thin film may be formed on the target object by supplying ozone to the target object and thermally oxidizing the target object .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an ozone treatment apparatus and an ozone treatment method according to an embodiment of the present invention are formed by using a batch type vertical heat treatment apparatus shown in FIG. An example in which a silicon oxide film is formed on an object to be processed will be described.
[0020]
As shown in FIG. 1, the heat treatment apparatus 1 includes a reaction tube 2 formed in a cylindrical shape with a ceiling whose longitudinal direction is directed in the vertical direction. The reaction tube 2 is made of a heat-resistant material such as quartz.
[0021]
Below the reaction tube 2, a manifold 3 made of stainless steel (SUS) formed in a cylindrical shape is arranged. The manifold 3 is connected to the lower end of the reaction tube 2 so as to be airtight.
[0022]
A lid body 4 is disposed below the manifold 3, and the lid body 4 is configured to be movable up and down by a boat elevator (not shown). When the lid body 4 is raised, the lower side of the manifold 3 is closed. The reaction chamber 2, the manifold 3, and the lid 4 constitute a processing chamber 3a.
[0023]
A wafer boat 5 made of quartz, for example, is placed on the lid 4. A plurality of objects to be processed, for example, semiconductor wafers 6 are accommodated in the wafer boat 5 at predetermined intervals in the vertical direction. The semiconductor wafer 6 accommodated in the wafer boat 5 is placed inside the processing chamber 3a when the wafer boat 5 is inserted into the reaction tube 2, and the placement region of the semiconductor wafer 6 is in the processing chamber 3a. The processing area 3b is configured. Further, the periphery of the processing area 3b forms a non-processing area.
[0024]
The reaction tube 2 has a gap (gap) D between the inner wall (inner wall) of the reaction tube 2 and the end of the wafer boat 5 (semiconductor wafer 6) in a state where the wafer boat 5 is inserted into the reaction tube 2. It is formed in the size which has. This gap D is, for example, about 20 mm to 50 mm in consideration of the flow rate of ozone, the pressure inside the reaction tube 2, the height of the reaction tube 2, and the like so that a predetermined exhaust conductance can be obtained in the processing chamber 3 a. Is set.
[0025]
Around the reaction tube 2, a temperature raising heater 7 made of, for example, a resistance heating element is provided so as to surround the reaction tube 2.
[0026]
An ozone supply pipe 8 is disposed on one side of the processing region 3b in the processing chamber 3a, for example, the lower non-processing region 3c (first non-processing region) . In the present embodiment, an ozone supply pipe 8 is inserted into the side surface of the manifold 3. The ozone supply pipe 8 is formed in a bent shape such that the tip portion 8a faces the direction (upward) of the processing region 3b, and has an ozone introduction portion 8b toward the processing region 3b at the tip portion 8a. is doing. For this reason, the ozone supplied from the ozone supply pipe 8 (ozone introduction part 8 b) is ejected above the reaction pipe 2.
[0027]
Further, the tip portion 8a is formed in a shape that optimizes the temperature, pressure, and flow rate in the processing chamber 3a with respect to the flow rate of ozone so that the active state of ozone can be maintained. The inner diameter of the ozone introduction portion 8b of the tip portion 8a is formed to be 2 mm to 20 mm, for example. Moreover, the length L of the ozone introduction part 8b is formed in 20 mm-1000 mm, for example. Furthermore, the length L of the ozone introduction part 8b is formed to be 1 to 100 times, preferably 10 to 40 times the inner diameter of the ozone introduction part 8b. Specifically, when the inner diameter of the ozone introduction part 8b is 10 mm, the length L of the ozone introduction part 8b is 10 mm to 1000 mm, preferably 100 mm to 400 mm. Further, the tip 8a passes through the outside of the processing region 3b (for example, the space formed by the gap D shown in FIG. 1) (third non-processing region) from the ozone supplied from the ozone supply pipe 8. The other side of the processing region 3b ( above the reaction tube 2) (second non-processing region) is disposed at a position.
[0028]
The ozone supply pipe 8 is connected to the ozone generator 9. The ozone generator 9 is composed of, for example, a plasma generator or the like, and generates ozone based on oxygen. An oxygen gas supply pipe 11 and a nitrogen gas supply pipe 12 are connected to the ozone generator 9 via a purifier 10. Then, oxygen gas from the oxygen gas supply pipe 11 and nitrogen gas from the nitrogen gas supply pipe 12 are supplied to the purifier 10, and the purifier 10 has purity conditions suitable for ozone generation (corrosion due to impurities, particularly moisture). Suppressing gas generation) is supplied to the ozone generator 9.
[0029]
An exhaust port 13 is provided on the side surface of the manifold 3 in the non-processing region 3c on one side of the processing region 3b. The exhaust port 13 is provided so as to face the ozone supply pipe 8 in the non-treatment region 3 c and exhausts the gas in the reaction tube 2.
[0030]
An exhaust pipe 14 is airtightly connected to the exhaust port 13. A combination valve 15 and a vacuum pump 16 are interposed in the exhaust pipe 14 from the upstream side. The combination valve 15 adjusts the opening degree of the exhaust pipe 14 to control the pressure in the reaction pipe 2 and the exhaust pipe 14 to a predetermined pressure. The vacuum pump 16 exhausts the gas in the reaction tube 2 through the exhaust pipe 14 and adjusts the pressure in the reaction tube 2 and the exhaust pipe 15.
[0031]
A purge gas supply pipe 17 for supplying a purge gas, for example, nitrogen gas, is inserted below the exhaust port 13 on the side surface of the manifold 3.
A control unit (not shown) is connected to the ozone generator 9, purifier 10, oxygen gas supply pipe 11, nitrogen gas supply pipe 12, combination valve 15, vacuum pump 16, and purge gas supply pipe 17. The control unit is composed of a microprocessor, a process controller, etc., measures the temperature, pressure, etc. of each part of the heat treatment apparatus 1, outputs a control signal etc. to each of the above parts based on the measurement data, and each part of the heat treatment apparatus 1 To control.
[0032]
Next, an ozone treatment method using the heat treatment apparatus 1 having the above-described configuration will be described taking a case where a silicon oxide film is formed on the semiconductor wafer 6 as an example. In the following description, the operation of each unit constituting the heat treatment apparatus 1 is controlled by a control unit (not shown).
[0033]
First, the wafer boat 5 containing the semiconductor wafer 6 is placed on the lid 4 with the lid 4 lowered. In addition, the inside of the reaction tube 2 (processing chamber 3a) is heated to a predetermined temperature, for example, 300 ° C to 1000 ° C, preferably 600 ° C to 900 ° C, by the heater 7 for raising temperature.
[0034]
Next, the lid body 4 is raised by a boat elevator (not shown), and the wafer boat 5 (semiconductor wafer 6) is loaded into the processing chamber 3a. Thereby, the semiconductor wafer 6 is accommodated in the processing chamber 3a, and the processing chamber 3a is sealed.
[0035]
After sealing the processing chamber 3a, pressure reduction in the processing chamber 3a is started. Specifically, the vacuum pump 16 is driven while controlling the opening of the combination valve 15, and the gas in the processing chamber 3a is discharged. The gas in the processing chamber 3a is discharged until the pressure in the processing chamber 3a is changed from normal pressure to a predetermined pressure, for example, 6.65 Pa to 399 Pa (0.05 Torr to 3 Torr). The pressure in the processing chamber 3a is maintained at 6.65 Pa to 399 Pa (0.05 Torr to 3 Torr).
[0036]
When the pressure in the processing chamber 3a is maintained at 6.65 Pa to 399 Pa (0.05 Torr to 3 Torr), ozone reacts so as to reach the ceiling of the reaction tube 2 (upper part of the wafer boat 5) from the ozone supply tube 8. Feed into tube 2. In order to make ozone reach the ceiling of the reaction tube 2, the ozone supplied from the ozone supply tube 8 becomes high speed, so that the flow rate of ozone per unit area increases. For this reason, ozone is supplied from the ozone supply pipe 8 at a high speed and a large flow rate. Ozone is supplied in a predetermined amount, for example, 1 liter / min to 30 liter / min, preferably 5 liter / min to 10 liter / min.
[0037]
Further, the tip 8a of the ozone supply pipe 8 is formed in a shape that optimizes the temperature, pressure, and flow velocity in the processing chamber 3a with respect to the flow rate of ozone, so that ozone passes outside the processing region 3b. Then, it is supplied to the ceiling of the reaction tube 2 and the supplied ozone concentration is maintained at, for example, 1 to 14 vol%.
[0038]
In general, when the inner diameter of the ozone introduction portion 8b is reduced, the pressure in the tip portion 8a (ozone introduction portion 8b) is increased, and it becomes difficult to maintain the active state of ozone. Conversely, when the inner diameter of the ozone introduction part 8b is increased, the flow rate of ozone is reduced, and the ozone ejected from the ozone supply pipe 8 is easily supplied to the ceiling of the reaction pipe 2. Further, when the length L of the ozone introduction portion 8b is shortened, it becomes difficult for ozone to flow as a high-speed viscous flow. Conversely, when the length L of the ozone introduction part 8b is increased, it becomes difficult to maintain the active state of ozone. For this reason, when the inner diameter and the length of the ozone introduction part 8b are changed and the shape in which the temperature, pressure, and flow velocity in the processing chamber 3a are optimized is examined, the inner diameter of the ozone introduction part 8b is 2 mm to 20 mm. It was confirmed that the length L of the introduction part 8b is preferably 20 mm to 1000 mm.
[0039]
Furthermore, when the relationship between the inner diameter and the length of the ozone introduction part 8b was examined, the length of the ozone introduction part 8b was 1 to 100 times, preferably 10 to 40 times the inner diameter of the ozone introduction part 8b. In particular, ozone was supplied to the ceiling of the reaction tube 2 through the outside of the treatment region 3b, and it was confirmed that the activity of ozone was not easily lost.
[0040]
Further, since the ozone generator 9 connected to the ozone supply pipe 8 is supplied with nitrogen gas in addition to oxygen gas, the generation efficiency of ozone generated by the ozone generator 9 is improved.
[0041]
The ozone that has reached the ceiling of the reaction tube 2 is supplied to the processing region 3 b by suction from the vacuum pump 16. Here, the pressure in the processing chamber 3 a is maintained at a low pressure such as 6.65 Pa to 399 Pa (0.05 Torr to 3 Torr) because the ozone once reaches the ceiling of the reaction tube 2. This is because the flow rate of the water becomes slower and the influence of the flow rate of ozone becomes smaller. Further, since the reaction tube 2 is provided with a gap D between the inner wall of the reaction tube 2 and the end portion of the semiconductor wafer 6, a predetermined exhaust conductance is obtained so that the inside of the processing chamber 3a can be maintained at a low pressure. Thus, ozone can be uniformly supplied to the processing region 3b. Furthermore, since the exhaust port 13 is disposed so as to face the ozone supply pipe 8, it is less likely to be affected by the ozone supplied from the ozone supply pipe 8 when supplying ozone to the processing region 3b. The exhaust conductance in 3a is improved, and ozone can be supplied more uniformly to the processing region 3b.
[0042]
When ozone is supplied to the processing region 3 b, oxygen atom radicals generated by the thermal decomposition of ozone cause an oxidation reaction on the surface of the semiconductor wafer 6, and a silicon oxide film is formed on the semiconductor wafer 6. The reaction product generated by the ozone treatment is sucked into the exhaust pipe 14 through the exhaust port 13 and exhausted outside the reaction pipe 2.
[0043]
When the silicon oxide film is formed on the surface of the semiconductor wafer 6, the supply of ozone from the ozone supply pipe 8 is stopped. Then, while controlling the opening of the combination valve 15, the vacuum pump 16 is driven to discharge the gas in the processing chamber 3 a, and then nitrogen gas is supplied from the purge gas supply pipe 17, so that the gas in the processing chamber 3 a is supplied. Is discharged to the exhaust pipe 14. In addition, in order to discharge | emit the gas in the process chamber 3a reliably, it is preferable to repeat discharge | emission of the gas in the process chamber 3a, and supply of nitrogen gas in multiple times.
[0044]
Finally, nitrogen gas is supplied from the purge gas supply pipe 17 to return the inside of the processing chamber 3a to normal pressure, and the wafer boat 5 (semiconductor wafer 6) is unloaded from the processing chamber 3a.
[0045]
As described above, according to the present embodiment, since ozone is supplied from the ozone supply pipe 8 so as to reach the ceiling of the reaction pipe 2, ozone is supplied at a high speed and a large flow rate. Moreover, since ozone is made to reach the ceiling of the reaction tube 2, ozone can be uniformly supplied to the processing region 3b. Furthermore, since the gap D is provided in the reaction tube 2, ozone can be uniformly supplied to the processing region 3b. In addition, since the exhaust port 13 is disposed so as to face the ozone supply pipe 8, ozone can be supplied more uniformly to the processing region 3b. For this reason, a silicon oxide film is uniformly formed on the semiconductor wafer 6.
[0046]
According to the present embodiment, the tip portion 8a is formed in a shape that optimizes the temperature, pressure, and flow velocity in the processing chamber 3a with respect to the flow rate of ozone, and therefore the pressure inside the tip portion 8a. And the temperature is difficult to increase. Even if the pressure and temperature are increased, the time during which ozone is exposed to high pressure and high temperature can be shortened. For this reason, it becomes difficult to lose the activity of ozone in the ozone supply pipe 8.
[0047]
According to the present embodiment, since the ozone generator 9 is supplied with nitrogen gas in addition to the oxygen gas, the generation efficiency of ozone generated by the ozone generator 9 is improved.
According to the present embodiment, since only one ozone supply pipe 8 is provided, the structure of the heat treatment apparatus 1 can be simplified.
[0048]
The present invention is not limited to the above-described embodiment, and for example, an object to be processed in which a silicon nitride film is previously formed on the semiconductor wafer 6 may be used. In this case, a laminated film of a silicon oxide film and a silicon nitride film or a silicon oxynitride film can be formed on the semiconductor wafer 6.
[0049]
The present invention is not limited to the case where it is used in a film forming process for forming a silicon oxide film on the semiconductor wafer 6. For example, the present invention is used in an ashing process for decomposing / removing organic substances deposited on the thin film surface. Also good. In this case, for example, when removing organic substances deposited on the surface of an SOG (Spin On Glass) film formed on a silicon oxide film, the flow rate of ozone treatment is increased and uniform ozone is formed on the entire surface of the SOG film. Processing can be performed. Moreover, you may use this invention for an annealing process.
[0050]
The ozone generator 9 is not limited to the one supplied with oxygen gas and nitrogen gas. For example, only the oxygen gas supply pipe 11 may be connected to the purifier 10 and only the oxygen gas may be supplied to the ozone generator 9. Also in this case, ozone can be generated by the ozone generator 9.
[0051]
The number of ozone supply pipes 8 is not limited to one and may be plural.
Further, the object to be processed is not limited to the semiconductor wafer 6 but may be a glass substrate, for example.
[0052]
【The invention's effect】
As described above, according to the present invention, the ozone flow rate can be increased and uniform ozone treatment can be performed on the entire surface of the object to be processed.
Further, according to the present invention, the flow rate of ozone can be increased and the pressure in the reaction tube can be maintained at a low pressure.
Furthermore, according to the present invention, the active state of ozone can be maintained.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a heat treatment apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic view of a conventional heat treatment apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 2 Reaction tube 3 Manifold 3a Processing chamber 3b Processing area 3c Non-processing area 4 Cover body 6 Semiconductor wafer 8 Ozone supply pipe 8a Tip part 8b Ozone introduction part 9 Ozone generator 11 Oxygen gas supply pipe 12 Nitrogen gas supply pipe 13 Exhaust port 14 Exhaust pipe 15 Combination valve 16 Vacuum pump

Claims (10)

An ozone treatment apparatus for treating an object to be treated with ozone,
Wherein the processing region of the workpiece to ozone treatment, and one side of the first non-processing region of the processing region, and the other side of the second non-processing region of the processing region, wherein the first non-processing region and A processing chamber having a third non-processing area leading to the second non-processing area ;
The tip is inserted into the processing chamber so as to be located in the first non -processing area, and reaches the second non -processing area from the first non-processing area through the third non-processing area. And at least one ozone supply pipe for supplying ozone into the processing chamber;
Ozone supply means connected to the ozone supply pipe;
An exhaust port that is provided in the first non-processing region and exhausts the gas in the processing chamber;
An exhaust means connected to the exhaust port and supplying ozone that has reached the second non-processing region to the processing region by exhausting the gas in the processing chamber;
An ozone treatment apparatus comprising: The first non-treated areas, located below the processing chamber, ozone treatment apparatus according to claim 1, wherein the this. 2. The ozone supply pipe is provided in the processing chamber, and the ozone supply pipe and the exhaust port are disposed at positions facing each other in the first non-treatment region. Or the ozone treatment apparatus of 2. The ozone supply tube has an ozone introduction portion whose distal end portion is bent to face the direction of the third non-processing region towards the third non-processing region,
The ozone treatment apparatus according to any one of claims 1 to 3, wherein a length of the ozone introduction part is formed to be 1 to 100 times an inner diameter of the ozone introduction part.   The ozone treatment apparatus according to claim 4, wherein the tip portion of the ozone supply pipe is bent upward. The ozone supply means has an ozone generation part composed of a plasma generator,
The ozone processing apparatus according to claim 1, wherein an ozone generation gas supply pipe for supplying oxygen gas and nitrogen gas is connected to the ozone generation unit.   The heat treatment apparatus comprises a heat treatment apparatus that maintains the inside of the treatment chamber in a heated and decompressed atmosphere, thermally oxidizes the object to be treated by ozone treatment, and forms a thin film on the object to be treated. The ozone treatment apparatus according to any one of claims 1 to 6. An ozone treatment method for treating an object to be treated with ozone,
From the ozone supply pipe arranged so that the tip is located in the first non-processing area on one side of the processing area of the processing chamber having the processing area for ozone-treating the object to be processed, the first non-processing via the third non-processing region leading to region and the other side a second non-processing region of the processing region, supplies ozone to reach the second non-processing region,
Ozone that reaches the second non- treatment region is supplied to the treatment region by exhausting the gas in the treatment chamber from an exhaust port provided in the first non-treatment region. Processing method.   The ozone treatment method according to claim 8, wherein the ozone supplied from the ozone supply pipe flows as a high-speed viscous flow and is supplied into the processing chamber at a temperature and pressure capable of maintaining an active state of ozone. . Maintaining the processing chamber at a predetermined temperature and a predetermined pressure;
The ozone treatment method according to claim 8 or 9, wherein ozone is supplied to the object to be treated, the object to be treated is thermally oxidized, and a thin film is formed on the object to be treated.

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