JP3437308B2 - Heat treatment furnace for semiconductor manufacturing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment furnace for semiconductor manufacturing equipment, and more particularly to a heat treatment furnace for semiconductor manufacturing equipment which performs heat treatment at a high temperature.

[0002]

2. Description of the Related Art There is a step of performing a hydrogen annealing process on a wafer in a semiconductor manufacturing process, and a conventional heat treatment furnace for performing this annealing process will be described with reference to FIG.

A reaction tube 2 is provided in a cylindrical heater 1.
A boat 4 loaded with wafers 3 in a horizontal posture in multiple stages is loaded in the reaction tube 2. A nozzle 5 provided upright along the inner wall of the reaction tube 2 is connected to a nitrogen gas supply source (not shown) through a first flow rate regulator 6 and a first valve 7, and the nozzle 5 is a second nozzle. It is connected to a hydrogen gas supply source (not shown) via the flow rate regulator 8 and the second valve 9. Further, an exhaust pipe 10 is connected to a lower end of the reaction pipe 2, the exhaust pipe 10 is connected to an exhaust device (not shown) through a third valve 11, and the exhaust pipe 10 is connected to an upstream side of the third valve 11. Is connected to an exhaust pump 13 via a fourth valve 12.

In the hydrogen annealing treatment, hydrogen gas is circulated at a high temperature to perform hydrogen annealing treatment on the wafer. However, due to the characteristics of hydrogen gas, there is a danger of explosion if the temperature is raised while oxygen is mixed. Therefore, before processing, the first valve 7, the second valve 9, and the third valve 11 are closed, the fourth valve 12 is opened, and the reaction tube 2 is opened by the exhaust pump 13.
The inside of the furnace is evacuated once to sufficiently remove oxygen in the furnace, then the fourth valve 12 is closed, the first valve 7 is opened to supply nitrogen gas, and the pressure inside the reaction tube 2 is restored to atmospheric pressure. After doing
The first valve 7 is closed, and the second valve 9 and the third valve 1 are closed.
Open 1 to supply hydrogen gas. Annealing is performed in a hydrogen gas atmosphere in the furnace by extruding nitrogen gas with hydrogen gas.

[0005]

Conventionally, the hydrogen annealing treatment is carried out at a furnace temperature of 400 to 450 ° C., but it may be carried out at a furnace temperature of 1100 to 1200 ° C. However, when the temperature in the furnace is 1100 to 1200 ° C., the rigidity and strength of the reaction tube decrease. Therefore, if the pressure inside the reaction tube is reduced in the process of replacing the inside of the reaction tube with nitrogen gas as described above, the reaction tube may be deformed during the pressure reduction. There was Therefore, there is a problem that the hydrogen annealing treatment at a high temperature cannot be performed in the conventional heat treatment furnace of the semiconductor manufacturing apparatus.

In view of the above situation, the present invention intends to enable heat treatment at a high temperature including a pressure reducing step.

[0007]

According to the present invention, the temperature of a reaction tube and a valve provided in the middle of a pipe for introducing an inert gas into a reaction tube, another valve provided in the middle of a depressurization path, are controlled. When a temperature detector for detecting and a temperature controller for comparing the temperature detector with a set temperature and issuing a signal when the detected temperature is higher than the set temperature are provided, and a signal from the temperature controller is issued In addition, the other valve is closed and the valve is opened, or an atmospheric pressure gauge for detecting the differential pressure between the internal pressure of the reaction tube and the atmospheric pressure is provided, and when the differential pressure becomes equal, The present invention relates to a heat treatment furnace of a semiconductor manufacturing apparatus configured to close a valve provided in the middle of a pipeline for introducing an inert gas.

[0008]

[Function] When the temperature of the reaction tube rises to a temperature at which reduction of the strength of the reaction tube becomes a problem during depressurization, the other valve provided in the depressurization path is closed to stop the depressurization, or further inert gas is added. A valve provided in the middle of the introducing pipe is opened to introduce an inert gas to restore the pressure in the reaction tube and reduce or remove the external pressure to the reaction tube to prevent damage to the reaction tube.

[0009]

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

In FIG. 1, the same parts as those shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

The main controller 15 is connected to the first valve 7 via a first switch box 16, and is connected to the third valve 11 via a second switch box 17.
Each of them is connected to the fourth valve 12 via the third switch box 18. The third switch box 18 has a fourth
The fourth switch box 21 is connected to the switch box 21, and the fourth switch box 21 is connected to the first switch box 16.

A temperature detector 19 such as a thermocouple for measuring the temperature of the reaction tube 2 is provided through the heater 1, and a temperature controller 20 is connected to the temperature detector 19, and the temperature controller 20 is connected to the third controller. Connect to the switch box 18. An atmospheric pressure gauge 22 is provided on the exhaust pipe 10, and the fourth switch box 21 is connected to the atmospheric pressure gauge 22.

The temperature controller 20 is preset with a set temperature 23 at which the strength of the reaction tube 2 decreases, for example, 850 ° C. when the material of the reaction tube 2 is quartz. In normal operation, the first valve 7, the second valve 9, the third valve 11, and the fourth valve 12 are opened / closed by an opening / closing command signal from the main controller 15.

Next, the operation of the depressurizing process at the start of processing the wafer 3 will be described.

The first valve 7, the second valve 9, and the third valve 11 are closed, the fourth valve 12 is opened, and the exhaust pump 13 depressurizes the reaction tube 2. The temperature detector 19 detects the temperature of the reaction tube 2 during the depressurization process, and the detection result is input to the temperature controller 20. The temperature controller 20 compares the detection result with the set value 23. As a result of the comparison, if the detected value of the temperature detector 19 is larger than the set value 23, the temperature controller 20 outputs the third value.
A signal for closing the fourth valve 12 is issued to the switch box 18, and an opening signal for the first valve 7 is issued to the first switch box 16 via the fourth switch box 21. Further, when the detected value of the temperature detector 19 is larger than the set value 23, the temperature controller 20 issues an alarm signal to warn an operator or the like.

Thus, the fourth valve 12 is closed, the exhaust in the reaction tube 2 is stopped, the first valve 7 is opened to introduce the nitrogen gas, and the pressure reduction is stopped and the pressure rise is performed at the same time. The damage and deformation of the reaction tube 2 are prevented. Furthermore,
The pressure in the reaction tube 2 is equal to that of the atmospheric pressure gauge 22 and the fourth pressure gauge.
Monitored by the switch box 21, when the atmospheric pressure is reached, a closing signal is output from the fourth switch box 21 to the first switch box 16, the first valve 7 is closed, and the inside of the reaction tube 2 is over-pressurized. Is prevented.

In the above embodiment, the first switch box 1
6, the second switch box 17, the third switch box 18, the fourth switch box 21 to the main controller 15
And the first valve 7, the third valve 11, and the fourth valve 12 are interposed to forcefully perform the damage prevention operation of the reaction tube 2 at the time of decompression. It may be performed by.

FIG. 2 shows another embodiment in which the damage prevention operation is carried out by the main controller 15. The signal from the temperature controller 20 and the signal from the atmospheric pressure gauge 22 are inputted to the main controller 15. The temperature controller 20 outputs a signal to the main controller 15 when the detected value of the temperature detector 19 is larger than the set value 23, and the main controller 15 closes the fourth valve 12, The first valve 7 is opened, the exhaust is stopped, and nitrogen gas is introduced into the reaction tube 2. Furthermore,
The atmospheric pressure gauge 2 indicates that the inside of the reaction tube 2 is at atmospheric pressure.
2 is detected, the main controller 15 causes the first valve 7
To block.

Needless to say, the temperature detector 19 may be changed as appropriate, such as temperature measurement by light detection other than a thermocouple, and nitrogen gas may be other inert gas such as argon gas. Of course, the gas may be used, and the present invention can be applied to a horizontal furnace.

[0020]

As described above, according to the present invention, it is possible to prevent the damage of the reaction tube in the high temperature heat treatment, and enable the high temperature heat treatment in the heat treatment furnace of the semiconductor manufacturing apparatus.
Further, since the protective operation is compulsorily performed, it is possible to prevent the damage of the reaction tube due to the operation mistake, and the like, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating another embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a conventional example.

[Explanation of symbols]

1 heater 2 reaction tubes 7 First valve 10 exhaust pipe 11 third valve 12th valve 19 Temperature detector 20 Temperature controller 22 Atmospheric pressure gauge

Claims (2)

(57) [Claims] 1. A valve provided in the middle of a pipeline for introducing an inert gas into the reaction tube, another valve provided in the middle of the decompression path, and a temperature detector for detecting the temperature of the reaction tube.
A temperature controller that compares the temperature detector with a set temperature and issues a signal when the detected temperature is higher than the set temperature; and when the signal from the temperature controller is issued, the other valve is turned on. A heat treatment furnace of a semiconductor manufacturing apparatus, which is configured to be closed and the valve is opened. 2. An atmospheric pressure gauge for detecting the pressure difference between the internal pressure of the reaction tube and the atmospheric pressure is provided, and a valve provided in the middle of the conduit for introducing the inert gas when the pressure difference becomes equal is closed. The heat treatment furnace of the semiconductor manufacturing apparatus according to claim 1, which is configured as described above.