JPH0552754A - Material gas detector for producing semiconductor - Google Patents

Abstract

PURPOSE:To enhance selectivity without being interfered with the gas or solvent in working environment by decomposing gas to be detected to a fine particulate powder and taking the concn. of said powder measured by a dust sensor as an electrical signal. CONSTITUTION:A predetermined volume of dry air is received in a bag 1 and a predetermined amount of tetraethoxysilane is injected in the bag 1 by a microsyringe to be evaporated. The generated vapor is controlled in its flow rate by a flow rate controller 5 and allowed to flow in a decomposing furnace 3 preliminarily held to predetermined temp. by the supply of a current while the dust in the vapor is removed by a filter 2. The fine particles (smoke) of SiO2 in the component converted to fine particulate components such as dust or mist in said furnace are detected by a dust sensor 4 to be converted to electrical signal output. This output is inputted to an amplification signal control part 6 to be converted to a signal which is, in turn, displayed on a display device 7 as a measured value and, when said signal becomes a definite value or more, an alarm is emitted from an alarm device 8. Therefore, this detector responds only to SiO2 with high selectivity without responding to other alcohols.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting minute amounts of various material gases used in semiconductor manufacturing, and is a detection device capable of issuing an alarm when the concentration is lower than an allowable concentration (threshold level value).

[0002]

2. Description of the Related Art This type of material gas detector for semiconductor production is strictly required to be easy to handle and safe to operate, and it is not only highly sensitive to the target gas but also highly selective. It is required to have sex. Currently, silane (SiH ₄ , monosilane), which is often used for forming silicon thin films, is used among the material gases used for manufacturing various types of semiconductors.
It is important to note that silane has a self-combusting property that spontaneously ignites and burns when its concentration increases, but a potentiostatic electrolytic sensor or a semiconductor sensor is used to detect the leakage into the indoor environment. It has been. Therefore, in the conventional material gas detector for manufacturing semiconductors of this type, when silane leaks at a high concentration, it spontaneously ignites and burns, resulting in the disappearance of the high-concentration silane, which leads to an indoor environment. Despite the large amount of leakage inside, there was a problem that silane could not be detected, causing an accident. Alternatively, the potentiostatic electrolysis type or semiconductor type gas sensor is sensitive to an organic solvent such as ethyl alcohol mixed in the atmosphere in a semiconductor manufacturing factory and gives a false alarm of leakage, which is unnecessary in the production control process. There was also the problem of getting into trouble.

Therefore, in order to solve the problems of such a conventional semiconductor material gas detection device, a potentiostatic electrolysis type silane sensor and SiO ₂ (dust, A silane leak detection sensor that combines and combines two types of smoke sensors that detect (smoke) has come to be used.

However, in recent years, tetraethoxysilane (Tetra Ethyl Ortho Si
Clone, hereinafter abbreviated as TEOS) has come to be used as a substitute for silane. However, TE
OS is said to be more toxic than silane, and its leak detection is far more important than silane. Due to such importance, as a device for detecting only TEOS without being interfered by an organic solvent such as ethanol, a highly accurate and expensive device such as a non-dispersive infrared absorption type or a Fourier transform infrared spectroscopy method is used. A large, high-class measuring device is used.

[0005]

The present invention is based on SiH ₄ , G
For the purpose of improving the selectivity in the detector of the material gas for semiconductor manufacturing such as eH ₄ , AsH ₃ , SbH ₃ , and TEOS, the miscellaneous gas mixed in the working environment and the organic solvent such as ethanol are used. It is an object of the present invention to provide a small-sized and inexpensive gas detection device capable of detecting with precision, accuracy, high selectivity, and high sensitivity without any interference with components.

[0006]

The structure of the present invention for achieving the above object will be described with reference to FIGS. 1 and 2 corresponding to the embodiments. In the first invention, the gas to be detected is heated. It is a material gas detection device for semiconductor manufacturing, characterized in that it is decomposed into fine particle powder by decomposition or combustion, its concentration is measured by a dust sensor, and its output is taken out as an electric signal.

A second aspect of the invention is the material gas detector for semiconductor manufacturing, wherein the gas to be detected is tetraethoxysilane.

[0008]

The function of TEOS will be described below as an example. The present invention is
Due to this structure, when TEOS is sealed in a bag, sucked by a pump, and thermally decomposed (combusted) in a decomposition furnace at 600 ° C or higher for about 0.1 to 1 _second , fine particles of SiO ₂ (smoke) become.

That is, the combustion chemical formula is Therefore, only SiO ₂ remains and the others do not. The gas body SiO ₂ (smoke) can be used by applying it to a dust sensor to extract it as an electrical signal and measuring and detecting its concentration. Therefore, the sensor sensitivity of the material gas detector for semiconductor manufacturing of the present invention is sensitive to only SiO ₂ and is not interfered with other alcohols. In the same manner as described above, if illustrated for other semiconductor manufacturing materials _{gas, SiH 4 + 2O 2 → SiO} 2 + 2H 2 O GeH 4 + 2O 2 → GeO 2 + 2H 2 O 2AsH 3 + 3O 2 → As 2 O 3 + 3H 2 O 2SbH 3 + 3O ₂ → Sb ₂ O ₃ + 3H ₂ O SiO ₂ , GeO ₂ , As ₂ O ₃ , generated by the reaction of
Sb ₂ O ₃ etc. may be detected by a dust sensor.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are diagrams showing one embodiment of the present invention, and the configuration will be described with respect to the block configuration diagram of the present invention shown in FIG. (1) is, for example, a bag made of a material that does not adsorb gas, and is prepared so as to maintain a predetermined gas concentration. That is, 10 liters of dry (synthetic) air from a cylinder is injected into the bag (1) with a predetermined amount of TEOS by microcyridine, and is tapped to evaporate so as to have a uniform concentration at room temperature. The dust existing in the atmosphere is removed so as not to give an error to the dust sensor (4) by introducing it from the bag (1) to the filter (2) having a hole diameter of about 0.1 μm. (3) is a decomposition furnace, for example, as shown in FIG. 2, a stainless steel pipe through which gas passes around the heating heating element (3a).
The gas inlet and the gas outlet are arranged between the filter (2) and the dust sensor (4) by winding (3b). The decomposition furnace (3) converts gas components into fine particle components such as dust and mist. Operate above the decomposition temperature of the gas to be measured. (T
In the case of EOS, 600 ° C or higher) The gas component is converted into an electric signal output by the dust sensor (4). Generally, a light scattering type dust sensor using a light beam of about 650 nm is suitable. A light-scattering smoke (fine particle) sensor that forms a sensing space using a laser beam, an infrared LED, an infrared lamp or the like as a light source other than the above can also be used. Further, there is also one that measures the mass of fine particles suspended in the gas or the concentration of smoke. (5) is a flow rate control unit that sucks atmospheric air into the preceding decomposition furnace (3) and dust sensor (4), which consists of an air pump (5a), a needle valve (5b), and a flow meter (5c). / Min is an appropriate value. (7) is an instruction unit for displaying the output of the dust sensor (4) as it is as a count value or by converting it to the concentration of the target component gas and displaying it as an analog meter or digital (numerical value). (8) is an alarm unit that issues an alarm according to the level such as the allowable concentration of the measurement gas component. Reference numeral (6) is an amplified signal control unit that receives the output signal of the dust sensor (4), processes the signal, and sends the processed signal to the indicator (7) and the alarm unit (8).

Next, the operation procedure of the apparatus will be described. The decomposition furnace (3) is previously energized and kept at 600 ° C or higher, and the bag (1) containing the sample gas is connected to the filter (2). Operate the air pump (5a), apply suction, check the flow rate with the flow meter (5c), and adjust with the needle valve (5b). The dust sensor (4) detects fine particles (smoke), inputs the detected signal to the amplified signal control unit (6), and displays the converted signal as a measurement value on the indicator (7). When the display value of the indicator (7) exceeds a certain value, the alarm device (8) operates.

Next, the data actually measured in the examples of the present invention will be shown. Table 1 shows the TEOS concentration versus the output numerical value of the measuring device, in which the output of the dust sensor (4) was read as the indicator of the indicator (7) using the standard sample of TEOS prepared in the above procedure.

[0013]

[Table 1]

Table 2 shows that only TEOS is 50 PPm, TEOS
These are the measured values measured with a potentiostatic electrolysis alcohol measuring device and the device of the present invention for three samples of 50 ppm of ethyl alcohol and 50 ppm of only ethyl alcohol.

[0015]

[Table 2]

Although the examples considered to be typical of the present invention have been described above, the present invention is not necessarily limited to the structures of these examples, and has the above-mentioned constitutional requirements referred to in the present invention, and The present invention can be appropriately modified and carried out within the scope of achieving the object of the present invention and having the following effects.

[0017]

As is apparent from the above description, according to the present invention, the fine particles of SiO ₂ (smoke) produced by taking out TEOS enclosed in a bag and thermally decomposing (combusting) it are electrically connected to a dust sensor. Since the signal is taken out as a signal and the concentration thereof is measured and detected, the sensor sensitivity of the present invention is sensitive to only SiO ₂ with high selectivity and not sensitive to other alcohols. It is possible to measure the concentration of the gas to be measured and to achieve accurate detection, which has a remarkable effect that cannot be expected from the conventional one.

The present invention is also based on the TEOS described above.
Other than, burns to produce fine particles, dust, and mist
It can be detected and measured by applying it to other material gases for semiconductor manufacturing such as silane, germane, stibine, arsine, and civolane.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of the internal structure of the decomposition furnace in FIG.

[Explanation of symbols]

 (1) Bag (2) Filter (3) Decomposition furnace (3a) Core (3c) Pipe (4) Dust sensor (5) Flow controller (5a) Air pump (5b) Needle valve (5c) Flow meter (6) Amplified signal control unit (7) Indicator (8) Alarm unit

Claims (2)

[Claims] 1. A material gas detection device for semiconductor manufacturing, characterized in that a gas to be detected is decomposed into fine powder particles by thermal decomposition or combustion, its concentration is measured by a dust sensor, and its output is taken out as an electric signal. . 2. The material gas detection device for semiconductor manufacturing according to claim 1, wherein the gas to be detected is tetraethoxysilane.