JPH1154495A - External torch oxidation device having a plurality of hydrogen nozzles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable parallel use of oxidation processing requiring a large rate of flow and oxidation processing requiring a small rate of flow, by providing a plurality of nozzles having different hydrogen gas ejection diameters, and independently controlling gas supply from the respective nozzles. SOLUTION: A small-flow hydrogen nozzle 1a having a range of a small rate of flow of 0.05 to 0.95 SLM is controlled by a small-flow mass flow controller 19a. A medium-flow hydrogen nozzle 1b having a range of medium rate of flow of 0.95 to 9.5 SLM is controlled by a medium-flow mass flow controller 19b. A large-flow hydrogen nozzle 1c having a range of a large rate of flow of 9.5 to 28.5 SLM is controlled by a large-flow mass flow controller 19c. In this manner, hydrogen gas having its rate of flow independently controlled is supplied to a combustion chamber 4. Thus, oxidation processing requiring a large rate of flow and oxidation processing requiring a small rate of flow can be used in parallel in one device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external combustion oxidizing apparatus, and more particularly, to an external combustion oxidizing apparatus suitable for use in semiconductor manufacturing, in which hydrogen gas and oxygen gas are burned to generate water vapor and thermally oxidize a wafer. About.

[0002]

2. Description of the Related Art Conventionally, an external combustion oxidizer having a plurality of hydrogen nozzles of this kind is disclosed in, for example, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Application Publication, there is provided two or more hydrogen supply nozzles to a combustion chamber for reacting and burning hydrogen and oxygen, and independently controlling the supply of each hydrogen, thereby impairing the life of the combustion chamber and the hydrogen nozzle. Instead, it is used for the purpose of burning a large amount of hydrogen.

FIG. 3 is a sectional view showing a conventional external combustion oxidizer having a plurality of hydrogen nozzles. As shown in FIG. 3, the external combustion oxidizing apparatus includes a hydrogen nozzle 1a, 1b, an oxygen nozzle 2, a connection pipe 3, a combustion chamber 4 for burning hydrogen, a heater 5 for heating the combustion chamber, a gas control device 6, a heat treatment. A heater 7, a quartz tube 8, a motor 9, a ball screw 10, a guide 11, a semiconductor wafer boat 12, a quartz tube cap 14, and a heat insulating jig 15.

FIG. 4 is a gas system diagram of the external combustion oxidizer of FIG. Referring to FIG. 4, first, oxygen is supplied to the combustion chamber 4.
The air-operated valve 16c is opened to supply the oxygen to the supply port, and the supply amount of oxygen is set to several SLMs. After a lapse of a predetermined time, the air-operated valves 16a and 16b are opened to start hydrogen combustion, and the air-operated valve 16j is closed. Mass flow controller for hydrogen 19
At b, several SLMs of hydrogen are supplied to the combustion chamber 4. Combustion chamber 4
After ignition, the oxygen supply amount is increased to a predetermined amount by the oxygen mass flow controller 18b, and thereafter the hydrogen supply amount is increased.

[0005] Combustion within the permissible hydrogen flow rate of the hydrogen nozzle 1b is followed by closing the air-operated valve 16f. In the case of combustion exceeding the permissible hydrogen flow rate, the air-operated valve 16k is closed and the air-operated valve 16j is opened. The combustion of hydrogen and oxygen is performed in the combustion chamber 4 by the two hydrogen nozzles 1a and 1b.

Normally, a mixed gas of water vapor and oxygen is supplied to the quartz tube 8 of FIG. 3 to oxidize the semiconductor wafer 13 in order to make the oxygen amount larger than １ ／ of the hydrogen amount.

[0007]

However, the above-mentioned prior art has the following problems.

The first problem is that the prior art aims to flow a large amount of hydrogen, and cannot flow hydrogen gas with a small flow rate and high accuracy.

[0009] The reason is that the hydrogen flow rate is controlled by only one mass flow controller for a large flow rate. Usually, a range in which the mass flow controller can accurately control the flow rate is determined (for example, 5 to 95% of the maximum flow rate), and a large flow rate mass flow controller (for example, a maximum flow rate of 30 SLM) accurately controls a small flow rate (for example, 0.1 SLM). I can't shed.

The second problem lies in the shape of the hydrogen nozzle. The shape of the nozzle that normally supplies hydrogen is selected for the following reasons. -Reduce the consumption of nozzles due to the combustion of hydrogen and secure a certain life.・ Prevent devitrification and deformation of the combustion chamber due to hydrogen combustion flame.

Therefore, in the oxidation treatment requiring a very small amount of water vapor, it is necessary to reduce the ejection diameter of the hydrogen nozzle. In the oxidation treatment requiring a large amount of water vapor, it is necessary to increase the number of hydrogen nozzles. At present, it cannot be increased more than a certain size from the size of the combustion tube.

For this reason, the range of the flow rate of hydrogen that can be flowed is naturally determined, so that there is a problem that a large flow rate and a small flow rate cannot be used together.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and has as its object to increase the supply range of the hydrogen gas flow rate to require an oxidation treatment requiring a large flow rate and a small flow rate. An object of the present invention is to provide an external combustion oxidizing apparatus that can use an oxidizing treatment.

[0014]

To achieve the above object, an external combustion oxidizer according to the present invention is directed to an external combustion oxidizer that oxidizes a semiconductor wafer by generating hydrogen vapor by burning hydrogen gas and oxygen gas. A plurality of nozzles having different hydrogen gas ejection diameters, and means for independently controlling gas supply from each of the plurality of nozzles.

[Summary of the Invention] In the present invention, in the case of an oxidation treatment requiring a small flow rate of steam, a hydrogen gas supply nozzle having a small ejection diameter is used, and the flow rate is controlled by a small flow rate mass flow controller. In the case of the oxidation treatment requiring a large flow rate of steam, a hydrogen gas supply nozzle having a large ejection diameter is used, and the flow rate is controlled by a mass flow controller for a large flow rate. However, in order to ignite safely, the initial ignition is performed using the hydrogen nozzle for extremely low flow rate and the mass flow controller for small flow rate, and then gradually to the predetermined flow rate using the hydrogen nozzle for large flow rate and the mass flow controller. To increase.

[0016]

Embodiments of the present invention will be described below. In a preferred embodiment, the external combustion oxidizing apparatus according to the present invention includes a semiconductor having a processing chamber for heating a semiconductor wafer, and a gas supply apparatus for supplying an inert gas, oxygen, water vapor, or the like to the processing chamber. In the external combustion oxidation of a wafer, the hydrogen gas supply nozzle has at least two nozzles having different ejection diameters to a combustion chamber for burning hydrogen, and the ejection diameter is suitable for the supply flow rate. Is controlled independently by a mass flow controller suitable for the supply flow rate.

That is, at least two or more nozzles of a proper hydrogen nozzle depending on the flow rate of the burning hydrogen, that is, a nozzle having a large nozzle diameter for a large flow rate and a small nozzle diameter for a small flow rate are provided. The mass flow controller used for each nozzle is also used, so that the range of combustible hydrogen flow rate can be widened and the flow rate accuracy can be improved. This means that an oxidation treatment requiring a large flow rate and an oxidation treatment requiring a small flow rate can be used in one apparatus.

In the embodiment of the present invention, particularly, a small flow rate of hydrogen can be burned with high accuracy. Therefore, the oxidation rate is reduced by diluting a small amount of steam with a diluent gas such as nitrogen. Will be able to As a result, even at higher temperatures, the controllability of the thickness of the ultra-thin film on the semiconductor wafer is improved.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 is a sectional view showing an embodiment of an external combustion oxidation apparatus having a plurality of hydrogen nozzles of the present invention, and FIG. 2 is a gas system diagram of FIG.

Referring to FIG. 1, an external combustion oxidation apparatus for a semiconductor wafer according to one embodiment of the present invention includes a combustion chamber 4 for burning hydrogen, a heater 5 for heating the combustion chamber 4, and a gas generated in the combustion chamber. A connection pipe 3 for supplying the steam, surplus oxygen and dilution gas to the quartz pipe 8, at least two hydrogen nozzles 1a, 1b, 1c for supplying hydrogen to the combustion chamber 4, and an oxygen nozzle 2 for supplying oxygen; A gas supply device 6 for controlling gas supplied to each nozzle.

Reference numeral 7 denotes a heat treatment heater, 9 denotes a motor, 10 denotes a ball screw, 11 denotes a guide, 12 denotes a semiconductor wafer boat, 13 denotes a semiconductor wafer, 14 denotes a quartz tube cap, and 15 denotes a heat insulating jig.

In the gas system diagram of FIG. 2, 16a to n are air-operated valves, 17 is a nitrogen mass flow controller,
18a and 18b are mass flow controllers for oxygen, 1
9a, 19b and 19c are hydrogen mass flow controllers.

In this embodiment, the range of the small flow rate is 0.05 to
0.95 SLM, medium flow rate range from 0.95 to 9.5 SL
Assuming that the range of M and the large flow rate is 9.5 to 28.5 SLM, the hydrogen nozzle 1a is for a small flow rate, 1b is for a medium flow rate,
1c is for a large flow rate, and the ejection diameter of the nozzle is a diameter suitable for flowing each flow rate (the ejection diameter of the nozzle is small, medium, and large in order).

The small flow hydrogen nozzle 1a is a small flow mass flow controller 19a, and the medium flow hydrogen nozzle 1b
Is a mass flow controller 19b for medium flow, and the hydrogen nozzle 1c for large flow is a mass flow controller 19c for large flow, and hydrogen gas whose flow rate is independently controlled is supplied.

Mass flow controller 19a for small flow rate
Is 1 SLM, the maximum flow rate of the medium flow mass flow controller 19 b is 10 SLM, and the maximum flow rate of the large flow rate mass flow controller 19 c is 30 SLM.
SLM.

The maximum flow rate of the mass flow controller for oxygen 18a is 1 SLM, and the maximum flow rate of 18b is 20 SLM.
It is. The maximum flow rate of the nitrogen mass flow controller 17 is 20 SLM, and the maximum flow rate of the dilution gas mass flow controller 20 is 50 SLM.

The semiconductor wafer boat 12 loaded with the semiconductor wafer 13 is inserted into the quartz tube 8. At this time, a mixed gas of oxygen and nitrogen is supplied to the quartz tube 8 in order to reduce oxidation due to the atmosphere. After the semiconductor wafer 13 reaches a predetermined processing position and the temperature in the quartz tube 8 is stabilized, an oxidation process is performed.

First, the case of an oxidation treatment requiring a small flow rate of steam will be described. In order to supply oxygen to the combustion chamber 4, the air-operated valves 16c and 16d are opened to reduce the supply amount of oxygen to 1 SL.
M is assumed. After the inside of the combustion chamber 4 is sufficiently filled with oxygen, 0.1 SLM of hydrogen is supplied to the combustion chamber 4 by the hydrogen mass flow controller 19a.

After ignition in the combustion chamber 4, the hydrogen supply amount is increased or decreased by a hydrogen mass flow controller 19a to a predetermined amount.
Thereafter, the oxygen supply amount is increased or decreased to a predetermined amount by the oxygen mass flow controller 18a.

When the steam generated by the diluent gas is diluted and supplied to the quartz tube 8, the air-operated valve 16n is opened to introduce the diluent gas, and the flow rate is controlled by the diluent gas mass flow controller 20. In this case, a mixed gas of steam, oxygen, and a diluent gas is supplied through the quartz tube 8.

Next, the case of an oxidation treatment requiring a medium flow rate of steam will be described. In order to supply oxygen to the combustion chamber 4, the air-operated valves 16c and 16d are opened to reduce the supply amount of oxygen to 1 SL.
M is assumed. After the inside of the combustion chamber 4 is sufficiently filled with oxygen, 0.1 SLM of hydrogen is supplied to the combustion chamber 4 by the hydrogen mass flow controller 19a. After ignition in the combustion chamber 4, the air-operated valve 16e is opened and 16d is closed. The supply amount of oxygen is increased to a predetermined amount by the mass flow controller for oxygen 18b, and the air-operated valves 16f and 16g are later opened, and the supply amount of hydrogen is increased to the predetermined amount by the mass-flow controller 19b for hydrogen. close.

Next, the case of an oxidation treatment that requires a large flow rate of steam will be described. In order to supply oxygen to the combustion chamber 4, the air-operated valves 16c and 16d are opened to reduce the supply amount of oxygen to 1 SL.
M is assumed. After the inside of the combustion chamber 4 is sufficiently filled with oxygen, 0.1 SLM of hydrogen is supplied to the combustion chamber 4 by the hydrogen mass flow controller 19a. After ignition in the combustion chamber 4, the air-operated valve 16e is opened and 16d is closed. The supply amount of oxygen is increased to a predetermined amount by the mass flow controller for oxygen 18b, and the air-operated valves 16h and 16i are opened later, and the supply amount of hydrogen is increased to the predetermined amount by the mass-flow controller for hydrogen 19c. close.

After the oxidizing process, nitrogen is supplied to the quartz tube 8, the semiconductor wafer 13 is discharged from the furnace, and a predetermined sequence is completed.

[0034]

As described above, according to the present invention, the following effects can be obtained.

The first effect of the present invention is that the width of the combustible hydrogen flow rate can be widened and the accuracy of the flow rate can be improved. The reason is that, in the present invention, at least two or more hydrogen nozzles are appropriately installed according to the flow rate of the burning hydrogen, and the mass flow controller is also adapted to the nozzles. For this reason, according to the present invention, the oxidation treatment requiring a large flow rate and the oxidation treatment requiring a small flow rate can be used in one apparatus.

The second effect of the present invention is that a small amount of hydrogen can be burned with high accuracy and the oxidation rate can be reduced by diluting a small amount of steam with a diluent gas such as nitrogen. That's what it means. As a result, even at higher temperatures, the controllability of the thickness of the ultra-thin film on the semiconductor wafer is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a gas system diagram of FIG.

FIG. 3 is a cross-sectional view showing a conventional semiconductor wafer external combustion device.

FIG. 4 is a gas system diagram of FIG. 3;

[Explanation of symbols]

1a, 1b, 1c Hydrogen nozzle 2 Oxygen nozzle 3 Connection pipe 4 Combustion chamber 5 Heater 6 Gas control device 7 Heat treatment heater 8 Quartz tube 9 Motor 10 Ball screw 11 Guide 12 Semiconductor wafer boat 13 Semiconductor wafer 14 Quartz tube cap 15 Heat insulation Tools 16a-n Air-operated valve 17 Mass flow controller for nitrogen 19a, 19b, 19c Mass flow controller for hydrogen 18a, 18b Mass flow controller for oxygen 20 Mass flow controller for dilution gas

Claims (2)

[Claims] An external combustion oxidizer for oxidizing a semiconductor wafer by generating water vapor by burning hydrogen gas and oxygen gas, comprising: a plurality of nozzles having different hydrogen gas ejection diameters; An external combustion oxidizer comprising means for independently controlling gas supply. 2. An external combustion oxidizing apparatus for oxidizing a semiconductor wafer by generating water vapor by burning hydrogen gas and oxygen gas, wherein nozzles having different ejection diameters are provided as nozzles for supplying hydrogen gas to a combustion chamber for burning hydrogen. Prepare at least two or more,
The ejection diameter of each nozzle is adapted to the supply flow rate,
The gas supply from each of the nozzles is independently controlled by a mass flow end roller suitable for each supply flow rate.