JPH0878404A - External combustion equipment of semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE: To ensure that oxygen burns with certainty without discharge of unburnt oxygen gas. CONSTITUTION: In external combustion equipment 30 connected into a reaction pipe of semiconductor manufacturing equipment, an oxygen feed pipe 36 and a hydrogen feed pipe 37 are connected into a combustion pipe 34, a heat absorbing plate 39 is provided in the vicinity of a hydrogen gas flow exit, a condenser heater 44 which condenses radiant heat to the heat absorbing plate is provided on the outside of the reaction pipe, or a thermocouple insertion pipe is connected into the reaction pipe so that the tip of the thermocouple insertion pipe is positioned in contact with or in the vicinity of the heat absorbing plate to make it possible to detect a heat absorbing plate temperature. Or such a construction may be employed as to have a flame sensor 47 to detect an ultraviolet ray of hydrogen flames and water vapor produced is fed to the reaction pipe. The combustion state is monitored by detecting the heat absorbing plate temperature with a thermocouple or detecting the presence of flames, thus ensuring the combustion of hydrogen with certainty.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing device, and more particularly to an external combustion device provided in a diffusion device.

[0002]

2. Description of the Related Art A diffusion apparatus has a step of forming a high-purity oxide film on the surface of a silicon wafer. In order to generate a high-purity oxide film on the surface of a silicon wafer, it is necessary to hold the wafer in a steam atmosphere at high temperature for a long time, and an external combustion device exists as a device for supplying high-purity steam.

The external combustion apparatus burns high-purity oxygen and hydrogen to generate water vapor, and supplies the water vapor to the reaction chamber in which the wafer is loaded.

A conventional external combustion device will be described with reference to FIG.

In the figure, 1 is a quartz tube, 2 is an oxygen inlet, 3 is a hydrogen or nitrogen inlet, 4 is a hydrogen injector, 5
Is a combustion heating furnace for the combustion combination of hydrogen and oxygen, 6 is an oxidation heating furnace, 7 is a silicon wafer placed in the quartz tube 1, 8
Is a boat for holding the silicon wafer 7.

Oxygen is supplied from the oxygen inlet 2 and hydrogen is supplied from the hydrogen inlet 3, and the supplied oxygen and hydrogen are heated in the combustion heating furnace 5 and burned to generate water vapor. This water vapor flows to the downstream side to give a water vapor atmosphere to the silicon wafer to form an oxide film.

[0007]

In the above-described conventional combustion apparatus for semiconductor manufacturing equipment, the temperature is set so that hydrogen is reliably burned in the furnace by the combustion heating furnace 5 which is the ignition source. It cannot be detected accurately or it cannot be monitored whether the supplied hydrogen is burning properly. Therefore,
There was a safety issue, such as the possibility of unburned hydrogen gas being discharged.

In view of the above situation, the present invention aims to provide an external combustion device in which hydrogen is certainly burned and unburned hydrogen gas is not discharged.

[0009]

According to the present invention, in an external combustion apparatus connected to a reaction tube of a semiconductor manufacturing apparatus, an oxygen supply pipe and a hydrogen supply pipe are connected in the combustion pipe, and oxygen is supplied from the oxygen supply pipe. A gas is provided so that hydrogen gas can be supplied from the hydrogen supply pipe, a heat absorbing plate is provided in the vicinity of the hydrogen gas outlet of the hydrogen supply pipe, and a radiant heat is collected outside the reaction pipe on the heat absorbing plate. An optical heater is provided, or a thermocouple insertion tube is inserted into the reaction tube, and the tip of the thermocouple insertion tube is brought into contact with and located in the vicinity of the heat absorbing plate to detect the temperature of the heat absorbing plate, or It is characterized in that a flame sensor for detecting ultraviolet rays of a hydrogen flame is provided.

[0010]

With the oxygen gas supplied from the oxygen supply pipe, the heat collecting plate is heated to a predetermined temperature by the condenser heater, and further hydrogen gas is supplied from the hydrogen supply pipe. The hydrogen gas comes into contact with the endothermic plate, ignites, and chemically burns with the oxygen gas, and the generated water vapor is supplied to the reaction tube. The combustion state is monitored by detecting the temperature of the endothermic plate with a thermocouple or by detecting the presence or absence of a flame to ensure the reliable combustion of hydrogen.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, a vertical semiconductor manufacturing apparatus in which the present invention is implemented will be described with reference to FIGS.

An outline of a semiconductor manufacturing apparatus will be described with reference to FIG.

The vertical reaction furnace 11 is provided at an upper position of the semiconductor manufacturing machine, and the reaction tube 12 is housed inside the reaction furnace 11. Below the reactor 11, a boat elevator 1
3 is provided, and the boat elevator 13 loads and withdraws the boat 15 loaded with the wafers 14 into the reaction tube 12. Wafers 14 are loaded into the boat 15 in a horizontal posture in multiple stages.

The wafer 14 is transferred between the semiconductor manufacturing machine and the outside while the wafer 14 is loaded in the wafer cassette 16, and the wafer cassette 16 is transferred to the wafer cassette transfer unit 1.
7 and then stored in the cassette stocker 18 inside, and the cassette stocker 1 is stored by the wafer transfer machine 19.
The wafers 14 of the wafer cassette 16 stored in the No. 8 are transferred to the boat 15 in the lowered state.

As described above, the boat elevator 13 loads the boat 15 into the reaction tube 12 and removes the boat from the reaction tube 12 when the film formation of the wafer 14 is completed.

The processed wafers are transferred from the boat 15 to the wafer cassette 16 of the cassette stocker 18 by reversing the above procedure, and further transferred to the outside of the semiconductor manufacturing machine.

FIG. 2 shows a cross section of the vertical reactor 11.

The reaction furnace 11 has a cylindrical heater 21, a soaking tube 22 inside the heater 21, and a reaction tube 12 inside the soaking tube 22.
Are concentrically provided, and the boat 15 is loaded into the reaction tube 12. The boat 15 is mounted on an elevator cap 24 via a boat cap 23, and the elevator cap 24 is provided on the boat elevator 13 and can be moved up and down.

A gas introducing pipe 25 is provided at the upper end of the reaction pipe 12.
And an exhaust port 26 is provided at the lower end of the reaction tube 12. The lower end of the gas introduction pipe 25 is connected to the gas supply pipe 27, and the exhaust port 26 is connected to the exhaust pipe 28.

With the boat 15 pulled out from the reaction tube 12, the required number of wafers 14 are loaded into the boat 15, and the boat elevator 13 raises the boat 15 to load it into the reaction tube 12. The heater 21 heats the inside of the reaction tube 12 to a predetermined temperature, and the reaction gas is introduced into the reaction tube 12 through the gas supply pipe 27 and the gas introduction pipe 25 to form a thin film on the surface of the wafer 14 and the reaction. The gas is exhausted through the exhaust port 26 and the exhaust pipe 28.

As shown in FIG. 3, an external combustion device 30 is connected to the gas supply pipe 27, and the water vapor generated in the external combustion device 30 passes through the gas supply pipe 27 and the gas introduction pipe 25 to cause the reaction. It is supplied to the pipe 12.

An external combustion device 30 according to the present invention will be described with reference to FIGS.

A combustion unit 32 is provided in the housing 31 in a vertical posture. Hereinafter, the combustion unit 32 will be described.

A transparent quartz combustion pipe 34 is provided inside the water cooling jacket 33, and a steam outlet pipe 35 extends from the upper end of the combustion pipe 34. The steam outlet pipe 35 is connected to the gas supply pipe 27. It Further, a quartz oxygen supply pipe 36, a quartz hydrogen supply pipe 37, and a quartz thermocouple insertion pipe 38 (see FIG. 7) are provided on the bottom surface of the combustion pipe 34 in a gastight manner in parallel with each other. The oxygen supply pipe 36 and the hydrogen supply pipe 37 are connected to the oxygen supply source and the hydrogen supply source, respectively. The thermocouple insertion pipe 38 is welded to the upper end of the hydrogen supply pipe 37, and a thermocouple (not shown) is inserted inside.

At the upper end of the hydrogen supply pipe 37, there is provided a heat absorbing plate 39 which is made of at least as high-purity silicon as the silicon wafer to be processed. The heat absorbing plate 3
Reference numeral 9 denotes a disc shape, which is present in a plane orthogonal to the radius of the combustion pipe 34 and is arranged on the outer peripheral side of the hydrogen supply pipe 37. The hydrogen gas outlet of the hydrogen supply pipe 37 is the heat absorption plate 39. There is an opening near.

As shown in FIGS. 8 to 10, a quartz pin 40 is projected from the fixed portion between the hydrogen supply pipe 37 and the thermocouple insertion pipe 38, and the heat absorbing plate 39 is attached to the pin 40. The tips of the left and right quartz heat absorbing plate retainers 41 and 42 welded to the side surfaces of the hydrogen supply pipe 37 are brought into contact with the heating surface of the heat absorbing plate 39. The heat absorbing plate 39 is held at two places on the periphery.

Since the heat absorbing plate 39 is positioned by the pin 40 and is held at two peripheral portions by the heat absorbing plate retainers 41 and 42, the heat crimping of the pin 40 may be slight or may be omitted. The heating flame in the caulking process is directly absorbed by the heat absorbing plate 39.
The heat absorbing plate 3
The oxidation of 9 can be minimized. Needless to say, there may be three or more heat absorbing plate retainers.

A heat retaining heater 43 is provided adjacent to the combustion tube 34.
The heat retaining heater 43 heats the cooling water flowing through the combustion pipe 34 and the water cooling jacket 33 so as not to lower the required temperature. Further, a condensing heater 44 is provided adjacent to the combustion tube 34 and facing the heat absorbing plate 39. The condensing heater 44 has a radiant heating element 45 such as a halogen lamp and a reflecting mirror 46 for collecting the radiant heat from the radiant heating element 45 on the heat absorbing plate 39. A through hole is provided between the reflecting mirror 46 of the water cooling jacket 33 and the combustion tube 34.

A flame sensor 47 for detecting the combustion state of hydrogen gas from below the bottom surface of the combustion pipe 34 is provided, and a water leakage sensor 48 is provided on the bottom surface of the casing 31.

The operation of the external combustion device 30 described above will be described below.

The radiant heat emitted from the radiant heating element 45 is collected by the reflecting mirror 46 on the heat absorbing plate 39 to heat the heat absorbing plate 39. Oxygen gas is introduced from the oxygen supply pipe 36, and the combustion pipe 34 is filled with oxygen gas while circulating a required flow rate.

The temperature of the endothermic plate 39 is monitored by the thermocouple inside the thermocouple insertion tube 38, and when the temperature reaches a predetermined temperature, hydrogen gas is introduced from the hydrogen supply tube 37. The hydrogen gas comes into contact with the endothermic plate 39, which has a high temperature in the oxygen atmosphere, and burns. Hydrogen gas is gradually increased to prevent generation of unburned gas so that the maximum flow rate is reached after the required time. In burning hydrogen gas, the material of the endothermic plate 39 is the same silicon as the wafer to be processed,
The wafer in the reaction tube 12 is not contaminated.

Further, whether or not the hydrogen gas is burning is monitored by detecting the ultraviolet rays of the hydrogen flame with the flame sensor 47. When ultraviolet rays are not detected, it is determined that there is no flame, and an error signal is issued to the main body controller to stop the apparatus or give a warning to an operator, and take necessary measures. Also, when the temperature of the heat absorbing plate 39 detected by the thermocouple does not reach the required temperature, an error signal is similarly issued to the main body controller.

Similarly, when the water leakage sensor 48 detects water leakage from the water cooling jacket 33 or the cooling pipe, an error signal is issued to the main body controller to stop the apparatus or give an alarm to the operator. Take necessary measures such as.

High-purity water vapor produced by the reaction combustion of hydrogen gas and oxygen gas is introduced into the reaction tube 12 through the water vapor outlet pipe 35, the gas supply pipe 27, and the gas inlet pipe 25, and the silicon wafer Used for oxide film formation.

At the end of combustion, first the supply of hydrogen gas is stopped and then the supply of oxygen gas is stopped. Further, in order to prevent abnormal combustion of hydrogen, nitrogen gas is introduced from the hydrogen supply pipe 37 before and after the supply of hydrogen gas.

The external combustion device 30 is used as the combustion unit 3
It is also possible to provide the semiconductor manufacturing apparatus 50 so that 2 is horizontal. In this case, the heat absorbing plate 39 is fixed as shown in FIG.
As shown in FIG. 13, thermal crimping of the pin 40 is sufficient.

[0039]

As described above, according to the present invention, the combustion location of hydrogen gas in the combustion pipe can be specified, and the temperature of the ignition source of hydrogen gas and the presence or absence of a flame can be monitored. Therefore, it is possible to stabilize the supply of water vapor to the reaction tube and improve the safety.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a semiconductor manufacturing apparatus.

FIG. 2 is a cross-sectional view of a vertical furnace reaction furnace of the semiconductor manufacturing apparatus.

FIG. 3 is a perspective view showing the relationship between the vertical reactor and an external combustion device.

FIG. 4 is a perspective view showing an internal structure of the external combustion device.

FIG. 5 is a sectional view of the external combustion device.

FIG. 6 is a front view of a combustion tube of the external combustion device.

FIG. 7 is a side view of the combustion tube.

8 is an enlarged view of a portion A in FIG. 7, which is a front view.

9 is an enlarged view of a portion A of FIG. 7, and is a side view.

FIG. 10 is an enlarged view of a portion A of FIG. 7, and is a plan view.

FIG. 11 is an explanatory diagram showing another embodiment of the present invention.

12 is an enlarged view corresponding to a portion A of FIG. 7, and is a side view.

FIG. 13 is an enlarged view corresponding to a portion A of FIG. 7, and is a plan view.

FIG. 14 is a sectional view of a conventional example.

[Explanation of symbols]

 12 Reaction Tube 30 External Combustion Device 34 Combustion Tube 36 Oxygen Supply Tube 37 Hydrogen Supply Tube 38 Thermocouple Insertion Tube 39 Endothermic Plate 40 Pin 41 Endothermic Plate Presser 42 Endothermic Plate Presser 43 Heat Keeper 44 Condenser Heater 45 Radiant Heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Watanabe 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Kokusai Electric Co., Ltd. (72) Koji Tomezuka 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Electric Co., Ltd. (72) Inventor Taketoshi Sato 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Kokusai Electric Co., Ltd.

Claims (5)

[Claims] 1. In an external combustion apparatus connected to a reaction tube of a semiconductor manufacturing apparatus, an oxygen supply pipe and a hydrogen supply pipe are connected to the inside of the combustion pipe to supply oxygen gas from the oxygen supply pipe and the hydrogen supply pipe. In order to supply more hydrogen gas, a heat absorbing plate is provided in the vicinity of the hydrogen gas outlet of the hydrogen supply pipe, and a condenser heater for collecting radiant heat on the heat absorbing plate is provided outside the reaction tube. External combustion equipment for semiconductor manufacturing equipment. 2. The semiconductor manufacturing according to claim 1, wherein the thermocouple insertion tube is inserted into the reaction tube, and the tip of the thermocouple insertion tube is brought into contact with and located in the vicinity of the heat absorption plate to detect the temperature of the heat absorption plate. External combustion device of the device. 3. The external combustion apparatus for a semiconductor manufacturing apparatus according to claim 1, further comprising a flame sensor for detecting ultraviolet rays of a hydrogen flame. 4. The heat absorbing plate is made of silicon as a material.
External combustion equipment for semiconductor manufacturing equipment in Japan. 5. A pin is provided at the tip of the hydrogen supply pipe, the pin is passed through the heat absorbing plate to position the heat absorbing plate, and a required number of heat absorbing plate retainers are fixed to the tip of the hydrogen supplying pipe. 2. The external combustion device of a semiconductor manufacturing apparatus according to claim 1, wherein the end of the presser is brought into contact with the heat absorbing plate to restrict movement of the heat absorbing plate in the pulling direction.