JP2014199230A - Gas detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas detection device which can selectively detect unsaturated fluorocarbon or carbonyl sulfide used as dry etching gas.SOLUTION: A gas detection device includes: filters 11 and 21 which have sulfuric acid silica gel layers 11a and 21a and porous polymer bead layers 11b and 21b, and which make at least one of unsaturated fluorocarbon and carbonyl sulfide penetrate; and a sensor part 2 which detects the gas which penetrates filters 11 and 21.

Description

  The present invention relates to a gas detection device that detects unsaturated fluorocarbons or carbonyl sulfide.

Dry etching gases such as unsaturated fluorocarbons and carbonyl sulfide are used as high-performance materials for microfabrication in the semiconductor manufacturing process. On the other hand, because of toxicity issues, the control concentration for unsaturated fluorocarbons is 2 ppm. Is regulated by an allowable concentration of 5 ppm.
Alarms that can detect this type of gas include those using a constant potential electrolytic sensor (for example, see Patent Document 1) that decomposes fluorocarbons in a pyrolysis furnace and detects the generated hydrogen fluoride, or acid gas. A sensor using a tape type sensor (for example, refer to Patent Document 2) using a color reaction due to the above is known.

JP-A-7-55764 JP-A-2001-324491

  However, semiconductor manufacturing factories use not only dry etching gas but also Novec, Florinart, Galden, etc. as cleaning agents, solvents, heat media, etc., which are gases that are not subject to detection. Hydrogen fluoride is generated by thermal decomposition. For this reason, there has been a problem that a constant potential electrolytic sensor in a semiconductor manufacturing factory has sensitivity to a fluorocarbon cleaning agent and a heat medium. Further, when a tape type sensor is used, the same problem is caused because the color reaction by the acid gas is used.

  In addition, alarm devices for detecting unsaturated fluorocarbons and carbonyl sulfides may be installed in semiconductor factories, where alcohol-based, ketone-based, ether-based, carboxylic acid-based, aromatic-based, etc. Since these various solvents or materials containing them as components are used, these gas species exist. When a pyrolysis furnace is used as pretreatment, the burden on the pyrolysis furnace becomes large under such an environment, and there is a problem that the pyrolysis furnace is deteriorated due to carbonization of gas due to incomplete combustion. In some cases, a catalyst is used to improve the decomposition efficiency in the thermal decomposition furnace. In this case, the decomposition efficiency may be lowered due to the disappearance of the catalytic reaction active site.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas detection device that can selectively detect unsaturated fluorocarbons or carbonyl sulfide used as a dry etching gas.

  The present inventors have intensively studied and found that an unsaturated fluorocarbon or carbonyl sulfide can be selectively permeated by using a filter having a sulfuric acid silica gel layer and a porous polymer bead layer, leading to the present invention. It was.

  That is, the first characteristic configuration of the gas detector according to the present invention includes a filter having a silica gel silica gel layer and a porous polymer bead layer, and transmitting at least one of unsaturated fluorocarbon and carbonyl sulfide. And a sensor unit that detects gas that has passed through the filter.

  Unsaturation because water, alcohol, volatile organic solvents, etc. in the gas can be adsorbed or captured by the filter by using a filter having a silica gel silica gel layer and a porous polymer bead layer as in this configuration. Fluorocarbon or carbonyl sulfide can be selectively detected.

  According to a second characteristic configuration of the gas detector according to the present invention, the porous polymer bead layer includes a gas molecule having a length in the molecular major axis direction of 6 mm or more, and a gas having a dipole moment of 1.4 debye or more. The point is that the molecule can be adsorbed or trapped.

According to this configuration, methanol, ethanol, fluorinate, Galden, Novec, volatile organic solvents such as toluene and xylene, etc. contained as miscellaneous gas components can be adsorbed or captured, and unsaturated fluorocarbon or carbonyl sulfide can be captured. It can be selectively transmitted and detected.
That is, first, alcohol-based or volatile organic solvent gases contained as miscellaneous gas components can be adsorbed on the silica gel silica gel layer, and at the same time electrostatic force (dipole-dipole interaction) is generated by the porous polymer bead layer. Can be absorbed.
On the other hand, gases with large molecular size such as Fluorinart, Galden, Novec, etc. are once adsorbed or trapped by the size exclusion effect of the porous polymer bead layer and electrostatic force (dipole interaction), and unsaturated fluorocarbon And for carbonyl sulfide, the time to penetrate the porous polymer bead layer can be significantly delayed.

  According to a third characteristic configuration of the gas detection device of the present invention, each of the filters is arranged, and at least two introduction lines for introducing the gas into the sensor unit, and introduction means for introducing the gas into the introduction line, Cleaning means for flowing a cleaning gas in a direction opposite to the gas introduction direction to the filter, and when the gas is introduced into one introduction line by the introduction means, the cleaning means is introduced into the other introduction line by the cleaning means. The cleaning gas is introduced, and switching means for switching an introduction line for introducing the gas is provided.

  According to this structure, since the introduction line which introduces gas into the sensor unit can be switched by the switching means, the filter of the introduction line on the side where no gas is introduced can be cleaned. Therefore, it is possible to detect the gas continuously without degrading the performance of the filter.

  A fourth characteristic configuration of the gas detection device according to the present invention further includes a second introduction unit that introduces the gas into the introduction line and discharges the gas from the introduction line without passing through the sensor unit. When introducing the gas into the introduction line by the introduction means, the cleaning gas by the cleaning means or the gas by the second introduction means is introduced into the other introduction line, and in each introduction line The second switching means for switching between the introduction of the cleaning gas by the cleaning means and the introduction of the gas by the second introduction means is provided.

  According to this configuration, the second switching unit can switch between the introduction of the cleaning gas by the cleaning unit and the introduction of the gas by the second introduction unit in one introduction line, and the gas is introduced by the introduction unit. Before introducing into the line, the introduction line can be filled with the gas in advance by introducing the gas into the introduction line by the second introduction means for a predetermined time. When introduced into the sensor unit, the gas can be introduced into the sensor unit with almost no time lag, and the gas can be detected almost continuously.

It is the schematic of the gas detection apparatus which concerns on 1st embodiment. It is the schematic which shows the operating method of the gas detection apparatus which concerns on 1st embodiment. It is the schematic of the gas detection apparatus which concerns on 2nd embodiment. It is the schematic which shows the operating method of the gas detection apparatus which concerns on 2nd embodiment. 2 is a graph showing the measurement results of unsaturated fluorocarbon concentration in Example 1. FIG. 2 is a graph showing measurement results of carbonyl sulfide concentration in Example 1. FIG. 2 is a graph showing the results of measuring the concentration of Galden (HT-135) in Example 1. 2 is a graph showing the concentration measurement results of florinate (FC-3283) in Example 1. FIG. 2 is a graph showing the measurement results of ethanol concentration in Example 1. 6 is a graph showing a measurement result of unsaturated fluorocarbon concentration in Example 2. It is a graph which shows the density | concentration measurement result of Galden (HT-135) in Example 2. FIG. It is a graph which shows the density | concentration measurement result of the fluorinate (FC-3283) in Example 2. FIG. 6 is a graph showing the measurement results of ethanol concentration in Example 2. It is the schematic of the gas detection apparatus used by the comparative example. It is a graph which shows the density | concentration measurement result of unsaturated fluorocarbon in a comparative example, Galden (HT-135), a fluorinate (FC-3283), and ethanol.

  A gas detection device according to the present invention has a sulfuric acid silica gel layer and a porous polymer bead layer, a filter that transmits at least one of unsaturated fluorocarbon and carbonyl sulfide, and a gas that has passed through the filter. And a sensor unit for detection. According to this gas detector, when detecting an unsaturated fluorocarbon or carbonyl sulfide in a semiconductor manufacturing factory or clean room, water, alcohol-based gas, fluorinate, Galden, Novec, volatile organics such as toluene, xylene, etc. Since the solvent or the like is adsorbed or captured by the filter, the unsaturated fluorocarbon or carbonyl sulfide can be selectively detected.

[First embodiment]
Hereinafter, an embodiment of a gas detection device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to this.

  As shown in FIG. 1, the gas detector 1 of the present embodiment includes a sensor unit 2 that detects gas, two introduction lines 10 and 20 that introduce gas into the sensor unit 2, and a dust filter from the gas suction port 3. 4, a suction pump 7 as an example of an introduction unit that sucks in through 4 and introduces into the introduction lines 10 and 20, and filters 11 and 21 disposed in the respective introduction lines 10 and 20. The tip of the suction pump 7 is connected to an exhaust port, an exhaust duct or the like (not shown) in order to discharge the sucked gas. Three-way valves 12, 22, 13, and 23 are provided on the upstream side and the downstream side in the gas introduction direction of the filters 11 and 21, respectively. A suction / supply line 30 serving also as a supply of clean air as an example of the cleaning gas is connected. The suction / supply line 30 is provided with a three-way valve 31. One side of the three-way valve 31 is connected to a supply line 40 including an activated carbon filter 41 and a supply pump 42 for supplying clean air. A suction line 50 having another suction pump 51 for sucking gas is connected to the other of 31. The tip of another suction pump 51 is connected to an exhaust port, an exhaust duct or the like (not shown) as in the case of the suction pump 7. An exhaust line 60 for discharging clean air that has passed through the filters 11 and 21 is connected to the three-way valves 12 and 22 on the upstream side of the introduction lines 10 and 20, respectively. It is connected to an exhaust duct or the like (not shown). In the present embodiment, the suction / supply line 30, the three-way valve 31, the supply line 40, the activated carbon filter 41, and the supply pump 42 correspond to the cleaning means in the present invention, and the suction / supply line 30, the three-way valve 31, The suction line 50 and another suction pump 51 correspond to the second introduction means in the present invention.

  The filters 11 and 21 have sulfuric acid silica gel layers 11a and 21a and porous polymer bead layers 11b and 21b. There are no particular restrictions on the positions where the sulfuric acid silica gel layers 11a and 21a and the porous polymer bead layers 11b and 21b are arranged. In this embodiment, the sulfuric acid silica gel layers 11a and 21a are arranged on the upstream side where gas is introduced. The porous polymer bead layers 11b and 21b are disposed on the downstream side. Further, the filters 11 and 21 include, for example, heaters that control the temperature of the filters 11 and 21 in order to control the adsorption power of gas to the sulfate silica gel layers 11a and 21a and the porous polymer bead layers 11b and 21b. Temperature controllers 11c and 21c are provided. In addition, when using a gas detection apparatus in an environment with small temperature fluctuations, such as a clean room, the temperature control parts 11c and 21c can also be abbreviate | omitted.

  The sulfuric acid silica gel layers 11a and 21a do not adsorb unsaturated fluorocarbon and carbonyl sulfide, but allow permeation, but can adsorb gas such as alcohol or volatile organic solvent.

  The porous polymer bead layers 11b and 21b are selected so as not to adsorb unsaturated fluorocarbons and carbonyl sulfides but allow them to permeate. As the porous polymer bead layers 11b and 21b, those capable of adsorbing or capturing gas molecules having a length in the molecular long axis direction of 6 cm or more and gas molecules having a dipole moment of 1.4 debye or more are preferable. By using such porous polymer bead layers 11b and 21b, the alcohol-based or volatile organic solvent gas contained as a miscellaneous gas component is adsorbed by electrostatic force (dipole interaction), Fluorinert, Galden, Novec, etc. are once adsorbed or trapped by the size exclusion effect of the porous polymer bead layer and electrostatic force (dipolar interaction), and porous to unsaturated fluorocarbons and carbonyl sulfide. The time for passing through the polymer bead layers 11b and 21b can be greatly delayed. The porous polymer bead layers 11b and 21b are not particularly limited, but preferably have a bead size of 50 to 120 mesh, and the polymer is a carboxylic acid, ester, ether, amide, nitrile, aldehyde, ketone, alcohol, amine. Those having any of the functional groups are preferred. Examples of the porous polymer bead layers 11b and 21b include a commercially available Polapack N (trade name) series. Polapack N (trade name) is a copolymer of divinylbenzene, ethylvinylbenzene and ethylene glycol dimethacrylate.

  The filters 11 and 21 configured in this manner do not adsorb unsaturated fluorocarbon and carbonyl sulfide, but allow permeation, but the gas species having a length in the molecular long axis direction of 6 cm or more, and the dipole moment of 1.4 debye or more. Gas species can be adsorbed or trapped. For example, it is possible to adsorb or capture gases such as fluorinate, Galden, Novec, alcohol-based and aromatic-based volatile organic solvents used in semiconductor manufacturing plants and the like to prevent false detection.

  The sensor unit 2 is not particularly limited as long as it can detect a gas to be detected among unsaturated fluorocarbon and carbonyl sulfide, and includes an electrochemical type, a semiconductor type, a catalytic combustion type, an ultraviolet / visible / infrared type, and the like. In this embodiment, a constant potential electrolytic carbon monoxide sensor including a sensor and a pyrolysis furnace is used. In the case of a constant potential electrolytic carbon monoxide sensor, the unsaturated fluorocarbon is decomposed in a pyrolysis furnace and carbon monoxide is generated. Therefore, the unsaturated fluorocarbon can be detected by detecting the generated carbon monoxide. .

An example of the operation method of the gas detector 1 configured as described above is as follows (FIG. 2).
The three-way valves 12 and 13 are controlled so that only one of the two introduction lines 10 and 20 communicates from the gas suction port 3 to the sensor unit 2. At this time, in the other introduction line 20, the upstream three-way valve 22 communicates with the filter 21 side and the exhaust line 60, and the downstream three-way valve 23 communicates with the filter 21 side and the suction / supply line 30. And the three-way valve 31 of the suction / supply line 30 is controlled to communicate with the supply line 40 (FIG. 2A). The suction pump 7 sucks the gas from the gas suction port 3, and the supply pump 42 supplies the air that has passed through the activated carbon 41 to the introduction line 20 as clean air.

  As a result, the gas passes through the filter 11, so that molecules having a length in the molecular major axis direction of 6 mm or more and molecules having a dipole moment of 1.4 debye or more are adsorbed or captured by the filter. Unsaturated fluorocarbons or carbonyl sulfide can be selectively detected. On the other hand, since clean air flows backward through the filter 21 and flows to the exhaust line 60, the gas adsorbed or captured by the filter 21 can be removed and the filter 21 can be cleaned.

  Then, after elapse of a predetermined time, for example, 2 minutes and 30 seconds, the three-way valve 31 of the suction / supply line 30 is communicated with the suction line 50 and the three-way valve 22 upstream of the other introduction line 20 is connected to the gas suction port 3 and the filter. 21 is controlled so as to communicate with the gas 21 (FIG. 2B), and the gas is caused to flow to the other introduction line 20 by another suction pump 51. Next, for example, after 30 seconds, the three-way valve 23 on the downstream side of the other introduction line 20 is controlled so that the filter 21 and the sensor unit 7 communicate with each other, and the three-way valve 12 on the upstream side of the one introduction line 10 is controlled. The filter 11 side and the exhaust line 60 communicate with each other, the downstream three-way valve 13 is controlled so that the filter 11 side communicates with the suction / supply line 30, and the three-way valve 31 of the suction / supply line 30 is connected to the supply line. It controls so that it may communicate with 40 (FIG.2 (c)). Thereby, the line through which gas passes switches to the other introduction line 20, and the filter 11 of one introduction line 10 is cleaned with clean air. Thereafter, similarly to the switching from FIG. 2A to FIG. 2B, for example, after 2 minutes and 30 seconds have elapsed, the three-way valve 31 of the suction / supply line 30 communicates with the suction line 50 and one introduction line 10 The three-way valve 12 on the upstream side is controlled so that the gas suction port 3 and the filter 11 communicate with each other (FIG. 2 (d)), and the gas is caused to flow to the other introduction line 20 by another suction pump 51. Thereafter, for example, after 30 seconds have elapsed, the process returns to FIG. Before switching the line for introducing the gas into the sensor unit 2, the gas is filled in the introduction line before being introduced into the sensor unit by pre-suctioning the gas with another suction pump 51. When the line to be introduced into the unit 2 is switched, the gas can be introduced into the sensor unit 2 almost without interruption, and the gas can be detected almost continuously.

As described above, the filter is controlled by controlling the three-way valve, repeating FIGS. 2A to 2D, and switching the line for introducing gas into the sensor unit 2 at regular intervals (for example, every 3 minutes). The gas can be continuously detected while cleaning 11 and 21.
In the present embodiment, the three-way valves 12, 22, 13, and 23 correspond to the switching means in the present invention, and the three-way valve 31 corresponds to the second switching means in the present invention.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. In the gas detection device 100 according to the present embodiment, as shown in FIG. 3, the three-way valve 31, the suction line 50, and another suction pump 51 of the suction / supply line 30 in the first embodiment are not provided, and suction / supply is performed. Line 30 is as supply line 40. For this reason, in this embodiment, the supply line 40, the activated carbon filter 41, and the supply pump 42 correspond to the cleaning means in the present invention. Other configurations are the same as those of the first embodiment.

  In the present embodiment, as shown in FIG. 4, in one of the two introduction lines 10 and 20, gas is sucked from the gas suction port 3 by the suction pump 7 through the filter 11. While being introduced into the sensor unit 2, in the other introduction line 20, clean air is supplied to the introduction line 20 by the supply pump 42, and the filter 21 is caused to flow backward (FIG. 4A), for a predetermined time (for example, After the elapse of 3 minutes, the three-way valve is switched, the other introduction line 20 is communicated from the gas suction port 3 to the sensor unit 2, and one introduction line 10 is communicated with the supply line 40 (FIG. 4 (b)). Thereafter, the gas introduction line is switched every predetermined time. Thereby, also in this gas detection apparatus 100, it is possible to continuously detect gas while cleaning the filters 11 and 21.

[Other Embodiments]
In said 1st, 2nd embodiment, the filters 11 and 21 are cleaned by switching the introduction lines 10 and 20 which introduce | transduce the gas into the sensor part 2 for every predetermined time, and making clean air flow back to the introduction line which is not introduce | transduced. However, the present invention is not limited to the example in which the gas is continuously detected. For example, it is possible to provide only one introduction line and provide a filter in the introduction line.

Hereinafter, examples using the gas detection device according to the present invention will be shown to explain the present invention in more detail. However, the present invention is not limited to these examples.
Example 1
In the gas detector 1 shown in the first embodiment, 1.5 g of sulfuric acid silica gel layers 11a and 21a of 60 wt% silica gel and 0.2 g of Polapack N (trade name) as the porous polymer bead layers 11b and 21b. Using a constant potential electrolytic carbon monoxide sensor as the sensor unit 2, 3.2 ppm of unsaturated fluorocarbon (C ₄ F ₆ ), 10 ppm of Galden (HT-135), 10 ppm of fluorinate (FC-3283) Each gas of 100 ppm ethanol was sucked for 1 hour, and each concentration was measured. In addition, gas suction is performed by switching the introduction line every 3 minutes, and on the introduction line on the side where the gas is not suctioned, the filter is cleaned with clean air for 2 minutes 30 seconds after switching, and the gas for 30 seconds thereafter. And the inside of the introduction line was replaced with gas.
Similarly, for 6 ppm of carbonyl sulfide, gas was sucked for 16 minutes and the concentration was measured.
As a result, as shown in FIGS. 5 and 6, unsaturated fluorocarbon and carbonyl sulfide are permeating through the filter, while other gases are adsorbed or captured by the filter as shown in FIGS. It was found that almost no detection was made.

(Example 2)
In the gas detection device shown in the second embodiment, as in Example 1, 1.5 g of sulfuric acid silica gel layers 11a and 21a of 60 wt% silica gel and POLAPACK N (product of porous polymer bead layers 11b and 21b) Name) and using a potentiostatic carbon monoxide sensor as a sensor part, sucking 3.2 ppm of unsaturated fluorocarbon (C ₄ F ₆ ) for 1 hour, 10 ppm of Galden (HT-135), 10 ppm of Each gas of florinate (FC-3283) and 100 ppm ethanol was sucked in for 3 hours, and each concentration was measured.
As a result, as shown in FIGS. 10 to 13, as in Example 1, the unsaturated fluorocarbon permeates the filter, but other gases are adsorbed or captured by the filter and are hardly detected. It was.

(Comparative example)
As shown in FIG. 14, in a gas detection device that sucks a gas without introducing a filter and directly introduces the gas into a constant potential electrolytic carbon monoxide sensor, 3.2 ppm of unsaturated fluorocarbon (C ₄ F ₆ ) 2 ppm of Galden (HT-135), 2 ppm of fluorinate (FC-3283), and 2 ppm of ethanol were aspirated for 3 hours, and the respective concentrations were measured.
As a result, as shown in FIG. 15, it was found that the presence of galden, fluorinate, and ethanol affects the detection of unsaturated fluorocarbons.

In the above Example 2 and Comparative Example, the average value of the interference ratio of Galden (HT-135), Fluorinert (FC-3283), and ethanol when the concentration of the unsaturated fluorocarbon (C ₄ F ₆ ) is 1 ppm is Asked. As a result, as shown in Table 1, it was found that interference of Galden (HT-135), Fluorinert (FC-3283), and ethanol can be suppressed by using a filter.

  As described above, it was confirmed that the gas detector according to the present invention can selectively detect unsaturated fluorocarbons and carbonyl sulfide.

  Since the gas detection apparatus according to the present invention can selectively detect unsaturated fluorocarbons and carbonyl sulfide, it can be applied to alarm devices installed in semiconductor manufacturing factories, clean rooms, and the like.

DESCRIPTION OF SYMBOLS 1 Gas detection apparatus 2 Sensor part 10, 20 Introduction line 11, 21 Filter 11a, 21a Sulfuric acid silica gel layer 11b, 21b Porous polymer bead layer 30 Suction / supply line 31 Three-way valve 40 Supply line 41 Activated carbon filter 42 Supply pump

Claims (4)

  Gas detection comprising a silica gel silica layer and a porous polymer bead layer, and comprising a filter that transmits at least one of unsaturated fluorocarbon and carbonyl sulfide, and a sensor unit that detects the gas that has passed through the filter. apparatus.   2. The porous polymer bead layer is configured to be capable of adsorbing or capturing gas molecules having a length in the molecular major axis direction of 6 cm or more and gas molecules having a dipole moment of 1.4 debye or more. The gas detector described in 1.   Each of the filters is arranged, and at least two introduction lines for introducing the gas into the sensor unit, introduction means for introducing the gas into the introduction line, and a direction opposite to the direction of introduction of the gas into the filter And a cleaning means for flowing a cleaning gas, and when the gas is introduced into one introduction line by the introduction means, the cleaning gas is introduced into the other introduction line by the cleaning means. The gas detection device according to claim 1, further comprising a switching unit that switches an introduction line to be introduced. A second introduction means for introducing the gas into the introduction line and discharging the gas from the introduction line without passing through the sensor unit;
When introducing the gas into the one introduction line by the introduction means, the cleaning gas by the cleaning means or the gas by the second introduction means is introduced into the other introduction line,
The gas detection device according to claim 3, further comprising a second switching unit that switches between introduction of the cleaning gas by the cleaning unit and introduction of the gas by the second introduction unit in each introduction line.

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