JPH0464892A - Exhaust device - Google Patents

Abstract

PURPOSE:To retain an uniform internal pressure of an exhaust pipe with a high accuracy and maintain a pressure in a reaction device in constant by a method wherein the title device is provided with a branch pipe, provided in the exhaust pipe of the reaction device and equipped with a valve opened by atmosphere when a pressure difference between an atmospheric pressure and the internal pressure of the exhaust pipe has become larger than a predetermined value, and pressure regulating valves, in the upstream and the downstream of the branch pipe, respectively. CONSTITUTION:An exhaust device 11 is provided with an exhaust pipe 13, connected to the exhaust port 12 of a heat treatment device 1, a branch pipe 14, provided in the exhaust pipe 13, pressure regulating valves 15-1, 15-2 and the like which are provided in the upstream side and the downstream side of the branch pipe. The pressure regulating valve 15-l, provided at the upstream side of the branch pipe 14, is regulated to adjust the flow rate of mixed gas G so that the detecting value of a pressure difference meter 16-1 becomes a desired value of -1-0mmH2O while the pressure regulating valve 15-2, provided in the downstream side of the branch pipe 14, is regulated under the condition of blockading the opening of the branch pipe 14 so that a pressure in the exhaust pipe 13 becomes a desired pressure difference or -15--20mmH2O, for example, by regulating the detected value of the pressure difference meter 16-2. Pressure regulation, effected in the branch pipe 14, is effected under the optimum pressure condition in such a manner.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to an exhaust system.

[Prior Art] Conventionally, in a reaction device for a film formation reaction performed under a constant pressure with gas in a semiconductor manufacturing process, the inside of the device is maintained at a constant pressure by adjusting a flow control valve provided in an exhaust pipe. Japanese Patent Application Laid-Open No. 62-63421, JP-A No. 63-238281, and JP-A No. 63-304620
There are publications etc.

However, in film-forming equipment such as heat treatment equipment for semiconductor manufacturing equipment, if the reactions that take place within the equipment are not carried out under certain conditions, the thickness of the formed film will become uneven, reducing the yield of semiconductor devices. It ends up.

Therefore, even in the exhaust device connected to the heat treatment apparatus, the pressure inside the exhaust pipe had to be delicately controlled to maintain a constant pressure inside the heat treatment apparatus.

By the way, a plurality of heat treatment devices are usually installed, and their exhaust devices are connected to the exhaust system of the entire factory, and the exhaust is exhausted using powerful fans. Therefore, when only a portion of the heat treatment apparatus is driven, the exhaust system is too strong and the negative pressure in the exhaust pipe becomes large, which greatly affects the pressure inside the heat treatment apparatus.

Therefore, a tributary pipe is provided in the exhaust pipe of the exhaust system, and a valve is installed in the tributary pipe perpendicular to the direction of gravity, and this valve is activated when the pressure difference between atmospheric pressure and the exhaust pipe reaches a predetermined value (exhaust (If the pressure inside the pipe is too low) Atmospheric pressure pushes up the valve, allowing the atmosphere to enter the exhaust pipe, increasing the pressure in the exhaust pipe. It has been developed.

[Problem to be solved by the invention] However, even in such an exhaust system, the weight of the valve is operated at -1 mmH2O, for example, so as to open and close in response to the pressure difference between the exhaust pipe internal pressure and atmospheric pressure. It is difficult to create such a system, and if the factory exhaust system becomes significantly negative pressure, the valve will be completely open and the exhaust pipe will not be able to maintain the desired constant pressure, causing the pressure inside the heat treatment equipment to drop. This has the disadvantage that the film thickness varies and the film thickness is non-uniform.

The present invention has been made in order to eliminate the drawback described in item 1.The present invention maintains the internal pressure of the exhaust pipe of the exhaust system at a constant level, so that even if it is connected to an exhaust system such as a factory exhaust system, the pressure will not be excessively reduced. The pressure inside the exhaust pipe can be maintained constant despite fluctuations in the factory exhaust system. Therefore, it is an object of the present invention to provide an exhaust device that can improve the quality of products because the pressure inside the reactor is also kept constant and the reaction is carried out under constant conditions.

[Means for Solving the Problems] In order to achieve the object described in item 1, the exhaust system of the present invention is provided in the exhaust pipe of a reaction device, and the exhaust system is provided in an exhaust pipe of a reaction device so that the pressure difference between the outside air pressure and the pressure inside the exhaust pipe becomes a predetermined amount -1-. This system is equipped with a branch pipe equipped with a valve that is opened by outside air, and pressure adjustment valves provided on the first and downstream sides of the branch pipe, respectively.

[Function] When the difference between the pressure inside the exhaust pipe and the outside pressure reaches a predetermined level (if the inside of the exhaust pipe is excessively depressurized), it is pushed open by the outside pressure opposing its own weight, and outside air is released. The exhaust pipe of the exhaust system is provided with a tributary pipe equipped with an automatically opening/closing valve that allows the flow of water to raise the internal pressure of the exhaust pipe to a predetermined value.

By installing pressure regulating valves upstream and downstream of the tributary pipe and adjusting the flow rate of ρ gas in the exhaust pipe, the valve installed in the tributary pipe can be operated under the best conditions, and the pressure between the reaction pipe and the outside pressure can be adjusted. The difference can be made to a desired constant pressure.

[Example] Hereinafter, an example in which the air extraction apparatus of the present invention is applied to a heat treatment apparatus for a semiconductor manufacturing process will be described with reference to the drawings.

A heat treatment apparatus 1, which is a reaction apparatus shown in FIG. 1, is equipped with a cylindrical process tube 5, and inside the process tube 5 is a mounting table on which a quartz boat 3 and the like for supporting a semiconductor wafer 2 to be processed is placed. 4 are provided. The process tube 5 is surrounded by, for example, a cylindrical resistance heating coil heater 6, and is closed with an opening or a lid 7, so that the inside of the process tube 5 can be heated at an appropriately set temperature of 500 to 1200°C. There is. The upper part of the process tube 5 has a reactive gas supply port 10 connected to a reactive gas supply system 9 via a flow meter 8, and the lower part of the process tube 5 has a reactive gas exhaust port 12 connected to an exhaust device 11. A mixed gas G of surplus reaction gas and reaction product gas after processing such as film formation on the semiconductor wafer 2 flows into the exhaust device 11 from the exhaust port 12.Exhaust device 11
is an exhaust pipe 13 connected to the exhaust port 12 of the heat treatment apparatus 1.
, a tributary pipe 14 provided in the exhaust pipe work 3, and a tributary pipe 14
Pressure regulating valves 151 and 1 provided in the 1st stream and downstream of
5-2 etc. will be provided. And this pressure regulating valve 15-
Differential pressure gauge 16 such as a manometer for each of 1 and 15-2
-1 and 16-2 are provided. As shown in FIG. 2, the branch pipe 14 has one end connected to the exhaust pipe 13, and the other end bent so that its axis is vertical. A large-diameter portion 18 is provided in the vertical portion 17, an O-ring 19 made of an elastic member is attached to the large-diameter portion 18, and a movable valve 20 is disposed on the O-ring 19'. For example, if the desired differential pressure between the outside pressure and the exhaust pipe 13 is 110 mm H2O, the movable valve 20 has a pressure of 1 atm = 10
From the relationship: 000mmH2O=I K g 7cm2, the weight should be Ig/cm2. The weight of the movable valve 20 is adjusted depending on the material and thickness.

A large number of heat treatment apparatuses 1 equipped with such exhaust devices 11 are usually installed in a factory, and the exhaust pipes 1 of these exhaust devices 11
3 are each connected via a common exhaust pipe 22 to an exhaust system fan 21 having a large exhaust capacity, such as a factory exhaust system.

The operation of the exhaust device of the heat treatment apparatus having such a configuration will be explained.

A case will be described in which only one of the plurality of heat treatment apparatuses 1 is in operation and the others are stopped. The flow meter 8 measures a predetermined amount of the reaction gas supplied from the reaction gas supply system 9, and the predetermined amount of the reaction gas is supplied to the reaction gas supply port 1 of the process tube 5.
Supply from 0. For example, 1000 by the coil heater 6.
A semiconductor wafer 2 is processed in a process tube 5 heated to .degree. After the treatment, the excess reaction gas and generated gas mixture G flows into the exhaust pipe 13 from the exhaust port 12 . At this time, the other heat treatment apparatuses 1 are not operated, and therefore the mixed gas G does not flow to the other exhaust apparatuses, so the exhaust fan 21
The ratio of the flow rate of the mixed gas G to the exhaust capacity No.j becomes smaller. If only the movable valve 20 of the tributary pipe 14 functions, it will not move until the negative pressure of the exhaust pipe 13 becomes extremely large, even if the desired differential pressure in the exhaust pipe internal pressure is, for example, -1 to OmmH,O or less. .

For example, when the temperature becomes -10 mm H2O or lower, the movable valve 20 provided in the branch pipe 14 is pushed by the external pressure and floats up from the O-ring 19. Then, outside air flows into the exhaust pipe 13, and the exhaust pipe 13 is kept at -10 mmH2O without being in an excessively negative pressure state. At this time, the pressure regulating valve 151 provided upstream of the tributary pipe 14 of the exhaust pipe 13 is adjusted to adjust the flow rate of the mixed gas G so that the detected value of the differential pressure gauge 16-1 is -1-QmmH2.
Make it 0. Further, the pressure regulating valve 15-2 downstream of the tributary pipe 14 is configured to maintain a desired differential pressure in the exhaust pipe 13, for example, -15 to 2 (111 mH) with the opening of the tributary pipe 14 closed.
20, the adjustment is made while detecting the detected value of the differential pressure gauge 16-2. As above, the pressure regulating valve 15-1.15-
By adjusting 2, the pressure adjustment in the tributary pipe 14 can be performed under optimal pressure conditions.

Therefore, the movable valve 20 of the tributary pipe 14 always operates at the optimum pressure condition of around -10 mm1-I20, and by adjusting the pressure regulating valve 15-1, the upstream part of the pressure regulating valve 15-1 can be adjusted to the desired value. Can be held in pressure saw. By appropriately adjusting the pressure regulating valve 15-2 in relation to the factory exhaust system and the equipment being operated, heat treatment can be performed under constant conditions regardless of pressure fluctuations caused by fluctuations in the suction force of the factory exhaust system. be able to.

Further, as another embodiment, as shown in FIG. 1, a differential pressure gauge 16
The pressure regulating valve 150- is activated by the output of 0-1 and 160-2.
1 and 150-2 may be automatically driven to perform feedback control.

The present invention is not limited to the first embodiment, but can also be applied to a single device that is not connected to a factory exhaust system. Further, the present invention is not limited to heat treatment equipment, and can be suitably used in equipment that performs processing while keeping the reaction pressure constant, such as a CVD equipment or a spin coater equipment that applies a processing liquid such as a resist.

[Effects of the Invention] As is clear from the following explanation, the exhaust system of the present invention has a movable valve that operates when the pressure difference between the outside pressure and the exhaust pipe increases. Since a pressure regulating valve is installed in each of the tributary tubes, the pressure in the tributary tube can be adjusted under optimal pressure conditions, ensuring uniformity with high precision and maintaining the intratracheal pressure. Can maintain pressure.

Therefore, semiconductor wafers can be processed uniformly, and high-quality products can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a diagram illustrating a main part of the embodiment shown in the figure. ... Heat treatment device (reaction device) 1 ... Exhaust device 3 ... Exhaust pipe 4 ... Branch pipe 5-1.15-2.150-1 .1.50-2...
・・Pressure regulating valve

Claims (1)

[Claims] A branch pipe provided in the exhaust pipe of the reactor and equipped with a valve that is opened by the outside air when the pressure difference between the outside pressure and the pressure in the exhaust pipe exceeds a predetermined value, and pressure regulating valves provided upstream and downstream of the branch pipe, respectively. An exhaust system characterized by comprising: