JPH0413756Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is used in semiconductor factories, etc., to detect leakage of processing gas or the occurrence of fire that occurs during the manufacturing process in VLSI factories, etc., and to appropriately control disaster prevention devices such as fire extinguishers and manufacturing processes. Concerning alarm and control devices.

Semiconductor factories, such as those for ultra-LSIs, which have made great strides in recent years, use silane gas when forming insulating films on silicon wafers, but such processing gases are toxic and can be dangerous if the concentration exceeds 2-5%. It is dangerous because it reacts with oxygen in the air and ignites and burns, and a fire thought to have been caused by these gases broke out at a super LSI factory, resulting in minor damage.

In consideration of the above points, this invention detects whether the leaked process gas is in its own state or reacts with oxygen in the air, burns, and generates combustion products. The present invention provides an alarm and control device for semiconductor factories and the like that can perform appropriate control in the early stages of a fire.

Hereinafter, a case where an embodiment of this invention is applied to a CVD apparatus (Chemical Vapor Deposition) used for forming an insulating film on a semiconductor wafer and its peripheral equipment will be described with reference to the drawings.

In FIG. 1, 1 is a silane gas cylinder, 2 is an ammonia gas cylinder, 3 is a storage box for storing these cylinders, and 6 is a nitride film forming unit that supplies silane gas and ammonia gas through pipes 4 and 5 to form an insulating film on a semiconductor wafer. A device (CVD), 8 is a detoxification device that supplies oxygen to the unreacted silane gas flowing out from the device 6 through the pipe 7 to force an oxidation reaction, that is, a combustion process; 10 is a detoxification device 8;
A detection box 12 is installed between the pipes 9 to monitor the state of the gas discharged into the exhaust duct 11.
1 is a vacuum pump that evacuates the inside of the forming apparatus 6, and 13 is an exhaust port that exhausts the air in the room. Furthermore, the storage box 3 and the detection box 10 include gas detectors G ₁ and G ₂ that detect leakage of processing gas such as silane gas, and a fire detector D ₁ that detects combustion products generated when the gas is combusted. , and D ₂ are provided. In this case, optical gas detectors that detect light scattered by gas particles can also be used as the gas detectors _G1 and _G2 , but a device known as a carbon monoxide detection element is disclosed in Japanese Patent Publication No. 55-14380. A gas detector suitable for this example, which responds to a low concentration of silane gas of 0.2 to 0.5% or more when a metal oxide semiconductor containing platinum black in a stannic oxide composition is aged in an atmosphere of silane gas. is obtained. Photoelectric smoke detectors and ionization smoke detectors can be used as fire detectors to detect combustion products, but the vertical axis shows the output of each sensor, and the horizontal axis shows the concentration of silane gas combustion products. According to the characteristic curve diagram in FIG. 3, the ionization type smoke detector b has higher sensitivity to the combustion products of silane gas and can detect the generation thereof earlier than the photoelectric type smoke detector a. Furthermore, the above-mentioned detectors G ₁ and G ₂ and _{the sensors D 1 and D 2 are} connected to the first OR as shown in FIG. Detection box 10 in circuit OR ₁
The gas detector G ₂ installed inside is connected to the second OR circuit directly, and the fire detector D ₂ is connected to the second OR circuit via an inverter.
OR ₂ and their outputs are connected to the third OR circuit
It is connected to OR ₃ , and its output is connected to a disaster prevention device such as a fire alarm or fire extinguisher, or a relay device (not shown) that appropriately controls the semiconductor manufacturing process.

Next, the operation of the above device will be explained. In the nitride film forming apparatus 6, a semiconductor wafer is placed therein, the vacuum pump 12 is used to create a vacuum, and then the silane gas cylinder 1 and the ammonia gas cylinder 2 are opened to supply silane gas and ammonia gas to the apparatus 6 to form the nitride film necessary for the semiconductor wafer. A nitride film, that is, an insulating film is generated. Further, the treated gas containing unreacted gas is forcibly oxidized in the abatement device 8 and is discharged from the exhaust duct 11 through the pipe 9 as a safe gas.

On the other hand, in such a situation, if a small amount of silane gas leaks from the silane gas cylinder 1 to the extent that it reacts with oxygen in the air and does not ignite and burn, the gas itself is detected and the gas detector G ₁ is activated, and the silane gas from the gas cylinder 1 is leaked. If a large amount of gas leaks and immediately reacts with oxygen in the air, flaming and burning, the combustion products will activate the fire detector _D1 , and the OR circuit will be activated.
Via OR ₁ and OR ₃ , a disaster prevention device (not shown) such as a fire alarm or fire extinguishing device or a relay device that controls this manufacturing process is operated. In addition, in the detection box 10, while the abatement device 8 is operating normally,
Since the combustion products incinerated through the pipe 9 are discharged through the pipe 9 to the exhaust duct 11, the gas detector G ₂ does not operate and does not output its output, and the fire detector D ₂ does not detect the combustion products. It detects and operates, but its output is inverted by an inverter, so
Nothing is input to OR circuit OR ₂ , and OR circuit OR ₂
doesn't work. However, when the abatement device 8 malfunctions and untreated silane gas is released and no combustion products are generated, the silane gas causes the gas detector to
G ₂ will operate, or fire detector D ₂ will be inoperative, but its output will be inverted by the inverter and an output will be generated, so the OR circuit OR ₂ will operate, and the OR circuit will operate.
Disaster prevention devices such as fire alarms and fire extinguishing devices (not shown) or relay devices that control the manufacturing process are operated through circuit OR ₃ .

In the above embodiment, the gas detector and the fire detector are provided separately, but they may be integrated and the circuit function shown in FIG. 2 may be incorporated.

As mentioned above, the fire alarm system of this invention is used in places where toxic and flammable process gases such as silane gas are used, such as in semiconductor manufacturing processes, and where process gases are stored and processed. A gas detector is installed to detect the process gas, and a fire detector is installed to detect the combustion products of the process gas.The secondary side of the abatement device that safely processes the process gas after use is equipped with a gas detector to detect the combustion products of the process gas. It is equipped with a gas detector to detect the gas and a fire detector equipped with an inverter on the output side to detect the combustion products of the process gas, and the operation of the detector and the sensor generates an alarm and also fires a disaster prevention device such as a fire extinguisher and a semiconductor. Since the manufacturing process is controlled, any type of leakage of process gas can be dealt with, and it can be dealt with by simply installing an inverter in the existing detector, so appropriate control can be carried out in advance or at the initial stage of a fire. This has the effect of providing an alarm and control device for semiconductor factories and the like that is easy to use and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of this invention, FIG. 2 is a circuit diagram thereof, and FIG. 3 is a characteristic curve diagram of a photoelectric smoke detector and an ionization smoke detector. 1...silane gas cylinder, 3...storage box, 6...
... Nitride film forming device, 8 ... Elimination device, 10 ... Detection box, 11 ... Exhaust duct, G ₁ , G ₂ ... Gas detector, D ₁ , D ₂ ... Fire that detects combustion products sensor.

Claims (1)

[Scope of claim for utility model registration] 1. Where toxic and flammable processing gases such as silane gas are used, such as in semiconductor manufacturing processes,
A gas detector for selectively detecting the processing gas and a fire detector for detecting combustion products of the processing gas are installed at locations where the processing gas is stored and processed.
In addition, the secondary side of the abatement device that safely processes the processed gas after use is equipped with a gas detector that selectively detects the processed gas and an inverter on the output side to detect the combustion products of the processed gas. What is claimed is: 1. An alarm and control device for a semiconductor factory, etc., which is equipped with a sensor, and issues an alarm by the operation of either of the above-mentioned detectors and the sensor, and controls a disaster prevention device such as a fire extinguisher, a semiconductor manufacturing process, etc. 2. The gas detector is an alarm and control device in a semiconductor factory or the like as set forth in claim 1, wherein the detection element thereof is made of a metal oxide semiconductor. 3. The alarm and control device for a semiconductor factory, etc. as set forth in claim 1, wherein the fire detector is an ionization smoke detector.