JPH06349812A - Device for heating clean gas - Google Patents

Abstract

PURPOSE:To provide a clean gas heating device which supplies a high temperature reaction gas to a reaction container, increases reaction speed and improves energy efficiency which allows uniformity of interplane film thickness. CONSTITUTION:A clean gas heating device is provided with a quartz tube 9, whose one edge is connected to a gas supplying side and the other edge is connected to a gas demanding side, a gas heating tube 10, which is formed of SiC and provided on the internal side of the quartz tube 9 so as to guide and heat a clean gas supplied from the gas supplying side and a halogen lamp 25, which is provided on the external side of the quartz tube 9 so as to heat a gas heating tube 10, and the temperature of the gas heating tube 10 is detected. The device is also provided with a control circuit 26 which controls the halogen lamp 25 on the basis of the detection result. A normal temperature clean gas supplied to the quartz tube 9 is heated to a high temperature while passing through the gas heating tube 10 and the heated clean gas is introduced to the gas demanding side, for example, to a reaction container for dry oxidation, and an oxide film is formed on the surface of a semiconductor wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean gas heating apparatus connected to a reaction vessel such as a furnace core tube for dry oxidizing semiconductor wafers.

[0002]

2. Description of the Related Art In a dry oxidation processing apparatus for forming an oxide film on the surface of a semiconductor wafer, a reaction vessel such as a furnace core tube is provided inside a diffusion furnace containing a heater. A wafer boat made of quartz is installed inside the reaction vessel, and a large number of semiconductor wafers are supported by the wafer boat at predetermined intervals.

A gas inlet is provided in the reaction vessel,
O ₂ gas and N ₂ gas are supplied from this gas inlet. These reaction gases are heated to a high temperature by a heater built in the diffusion furnace. For example, in the case of a silicon wafer, a silicon oxide film (SiO ₂ film) is formed on the surface of the silicon wafer.
Is formed.

Also in the CVD apparatus, similarly, reaction gases such as SiH ₄ , SiH ₂ Cl ₂ and NH ₃ gas are supplied to a reaction vessel in which a large number of semiconductor wafers are supported and accommodated in a wafer boat, The reaction gas is heated to a high temperature by a heater provided around the reaction container, and a film is formed on the surface of the semiconductor wafer.

[0005]

However, the dry oxidation processing apparatus and the CVD apparatus configured as described above are
A reaction gas at room temperature is heated to a high temperature by a heater provided on the outer periphery of the reaction container. In this case, it is necessary to heat the reaction gas to a high temperature, but it takes a long time to raise the temperature of the diffusion furnace to a high temperature, and there is a problem that the rise time is slow and the reaction rate is slow. Further, it is difficult to maintain a uniform temperature from one end side to the other end side of the reaction container, and it is not possible to obtain a uniform inter-plane film thickness when processing a large number of semiconductor wafers.

The present invention has been made in view of the above circumstances, and an object thereof is to supply a reaction gas at a high temperature to a reaction container when it is adopted in a dry oxidation processing apparatus or a CVD apparatus. It is possible to increase the reaction speed, obtain the uniformity of the film thickness between the surfaces, and
It is an object of the present invention to provide a clean gas heating device that can be used for hot air drying as clean drying after cleaning a liquid crystal substrate and a disk substrate with pure water.

[0007]

In order to achieve the above object, the present invention provides a quartz tube having one end connected to a gas supply side and the other end connected to a gas demand side, and a quartz tube inside the quartz tube. A gas heating pipe made of SiC for guiding the clean gas supplied from the gas supply side and heating the clean gas; heating means provided outside the quartz pipe for heating the gas heating pipe; The control means is configured to detect the temperature of the heating tube and control the heating means based on the detection result.

The clean gas at room temperature supplied to the quartz tube is heated to a high temperature when passing through the inside of the gas heating tube made of SiC, and the heated clean gas is on the gas demand side, for example, a reaction container for dry oxidation. Then, an oxide film is formed on the surface of the semiconductor wafer.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show the first embodiment, and FIG. 1 shows the entire dry oxidation treatment apparatus. Reference numeral 1 is a furnace core tube as a reaction vessel. The furnace core tube 1 is made of cylindrical quartz glass, and the furnace core tube 1 is housed in a diffusion furnace 3 having a heater 2 built therein. A wafer boat 4 made of quartz is installed inside the furnace core tube 1, and a large number of semiconductor wafers 5 are supported by the wafer boat 4 at predetermined intervals.

Reference numeral 6 is a clean gas heating device, and 7 is the main body of the device. The device body 7 is provided with a through passage 8 penetrating in the lateral direction, and the through passage 8 has a cylindrical quartz tube 9
Has been inserted. Inside the quartz tube 9, a gas heating tube 10 made of SiC is inserted over the entire length, and the gas heating tube 10 is provided at both ends of the quartz tube 9 with an inlet end plate 11 made of quartz glass and an outlet. It is sealed by the side end plate 12.

As shown in FIG. 2, an annular space is formed between the quartz tube 9 and the gas heating tube 10, and a partition tube 13 is interposed in this annular space. This partition tube 13
One end 13a is provided integrally with the inlet side end plate 11,
The other end 13b is separated from the outlet side end plate 12.

Therefore, the outside and the inside of the partition tube 13 inside the quartz tube 9 are formed into a bent gas outer flow passage 15 which communicates with the folded portion 14 and detours, and the gas outer flow passage 15 is formed on the inlet side end plate. Gas heating pipe 10 near 11
It communicates with the gas inside flow passage 17 through a through hole 16 formed in the.

Further, a first gas introducing pipe 18 and a second gas introducing pipe 19 are provided on the inlet side end plate 11 so as to project therefrom and communicate with the gas outer flow passage 15, and the inlet side end is also provided. The plate 11 is provided with a thermocouple 20 for detecting the temperature of the gas inner flow passage 17.

The outlet end plate 12 has a hot gas outlet pipe 2
1 is provided so as to project to the outside, and this high temperature gas outlet pipe 21
Communicates with the gas inside flow passage 17 through a through hole 22 formed in the outlet end plate 12. The hot gas outlet pipe 21 is connected to the hot gas inlet pipe 23 of the furnace core pipe 1 and the joint 2
4 are connected.

Further, as shown in FIG.
A heating device is provided inside. That is, a plurality of straight tube type halogen lamps 25 are arranged at equal intervals in the circumferential direction so as to surround the quartz tube 9, and the halogen lamps 25 are provided over substantially the entire length of the apparatus main body 7 in the longitudinal direction. ing.

A reflecting plate 25a is arranged outside the halogen lamp 25 so as to collect light toward the axis o of the gas heating tube 10.
The gas heating pipe 10 is heated to a high temperature.

The halogen lamp 25 is electrically connected to a power source (not shown) via a control circuit 26, and the control circuit 26 supplies a current to the halogen lamp 25 based on the detection result of the thermocouple 20. It is configured to control and maintain the gas heating pipe 10 at a substantially constant temperature.

Next, a case will be described in which the semiconductor wafer 5 installed inside the furnace core tube 1 is dry-oxidized by using the clean gas heating device 6 configured as described above. First, when a plurality of halogen lamps 25 of the apparatus main body 7 are turned on, the irradiation light from these halogen lamps 25 is focused toward the axis o of the gas heating tube 10, and the irradiation heat heats the gas heating tube 10 to a high temperature. It is heated to a temperature (around 1200 ° C).

In this state, clean O ₂ gas at room temperature is supplied from the first gas introduction pipe 18, and clean N ₂ gas at room temperature is supplied from the second gas introduction pipe 19 (maximum 50 l / mi).
n) Then, these gases are mixed, and the reaction gas flows through the gas outer flow passage 15 outside the partition tube 13 inside the quartz tube 9 in the direction of the arrow, and inside the partition tube 13 via the folded portion 14. Through the gas outer flow passage 15.

Further, the reaction gas flows in the gas inner flow passage 17 in the arrow direction from the gas outer flow passage 15 through the through hole 16 formed in the gas heating pipe 10 near the inlet side end plate 11. During this period, the reaction gas is a high temperature gas heating pipe 10
Is heated to a high temperature (around 1000 ° C.).

The high-temperature reaction gas flows from the through hole 22 through the high-temperature gas outlet pipe 21 to the high-temperature gas inlet pipe 23, and is supplied into the furnace core tube 1. Therefore, when the semiconductor wafer 5 inside the furnace core tube 1 is, for example, a silicon wafer, a silicon oxide film (SiO ₂ film) is formed on the surface of the silicon wafer.
Is formed. In this case, since the reaction gas having a high temperature is directly supplied to the inside of the furnace core tube 1, the reaction speed is increased as compared with the conventional method in which the reaction gas having a normal temperature is supplied. There is an effect that uniformity can be obtained.

FIG. 4 shows a second embodiment, in which the entire gas heating tube 10 made of SiC installed inside the quartz tube 9 is covered with quartz glass 27. Also,
The gas outer flow passage 15 and the gas inner flow passage 17 communicate with each other through a through hole 16 formed in the inlet end plate 11. The other structure is the same as that of the first embodiment.

With this structure, the gas heating pipe 19 made of SiC is not in contact with the reaction gas, and the reaction gas is indirectly heated via the quartz glass 27, so that cleaner gas heating is possible. Becomes

Further, the clean gas heating apparatus of the present invention is not limited to the dry oxidation treatment, and can be applied to the CVD apparatus as well as the clean drying after cleaning the silicon wafer, the liquid crystal substrate and the disk substrate with pure water. It can also be used for hot air drying. Furthermore, it can be used for heating liquid chemicals and pure water, and its application range is wide.

Although the halogen lamp is used as a means for heating the gas heating tube, the present invention is not limited to this, and a heater used in a diffusion furnace may be used, and the heating means is not limited.

[0026]

As described above, according to the present invention, when it is adopted in a dry oxidation treatment apparatus or a CVD apparatus,
A high-temperature reaction gas can be supplied to the reaction vessel, and the reaction rate can be increased and the inter-plane film thickness can be made uniform.

Further, since the clean gas can be heated and ejected, there is an effect that it can be used for hot air drying as clean drying after cleaning the silicon wafer, the liquid crystal substrate and the disk substrate with pure water.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a dry oxidation processing apparatus showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the clean gas heating apparatus according to the embodiment.

FIG. 3 is a cross-sectional side view of the clean gas heating device of the embodiment.

FIG. 4 is a vertical sectional front view of a clean gas heating apparatus showing a second embodiment of the present invention.

[Explanation of symbols]

 9 ... Quartz tube 10 ... Gas heating tube 15 ... Gas outer flow passage 17 ... Gas inner flow passage 25 ... Halogen lamp 26 ... Control circuit

Claims (2)

[Claims] 1. A quartz tube having one end side connected to a gas supply side and the other end side connected to a gas demand side, and a clean gas which is provided inside the quartz tube and which is supplied from the gas supply side while guiding the clean gas. A gas heating tube made of SiC for heating the gas, a heating means provided outside the quartz tube for heating the gas heating tube, a temperature of the gas heating tube is detected, and the heating means is controlled based on the detection result. A clean gas heating apparatus comprising: a control unit for controlling. 2. The clean gas heating apparatus according to claim 1, wherein the gas heating pipe has a flow passage through which the clean gas flows, and directly or indirectly heats the clean gas.