JP4385310B2 - Organic compound desorption method and clean room facility with desorption function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic compound desorption method and a clean room facility with a desorption function , and more particularly to an organic compound desorption method for desorbing an organic compound adsorbed on a filter of the clean room facility from the filter and a clean room facility with the desorption function .
[0002]
[Prior art]
A high-performance, high-clean clean room that manufactures semiconductors removes dust in the air with a fan filter unit (hereinafter referred to as FFU), and supplies the clean air to the clean room to make the clean room highly clean. Is maintained. In the clean room, the temperature and humidity are also controlled, and it is normally kept substantially constant at 23 ° C. and around 45% RH.
[0003]
Inside the FFU, HEPA (High Efficiency Particulate Air) filters and ULPA (Ultra Low Penetration Air) filters are installed as air filters to collect dust in the air, and high cleanliness is required in the clean room. In this case, a ULPA filter is used. In this case, most of the dust is removed in advance by a coarse dust filter or HEPA filter installed in an air conditioner (AHU: Air Holding Unit), so that there is little dust accumulated on the ULPA filter, and the life of the ULPA filter is Very long.
[0004]
By the way, it is known that various organic compounds are adsorbed on the glass fiber constituting the ULPA filter. If the organic compound is adsorbed on the ULPA filter over a long period of time and the adsorbed amount exceeds the saturated adsorbed amount of the ULPA filter, the organic compound may be desorbed from the ULPA filter and contaminate the clean chamber. For this reason, in the conventional clean room facilities, the ULPA filter is replaced after being used for a certain period.
[0005]
[Problems to be solved by the invention]
However, the exchanged used ULPA filter often has sufficient dust collecting ability, which is the original installation purpose. For this reason, it is uneconomical and wasteful to replace the ULPA filter only with the problem of organic compounds. In addition, there is a problem that the work of replacing the ULPA filter once incorporated in the clean room facility requires a great deal of labor.
[0006]
Furthermore, in conventional clean room facilities, when the temperature in the clean room rises when the air conditioner fails or when the operation is stopped in summer, DOP (dioctyl phthalate) and DBP (dibutyl phthalate), which are organic compounds, are extracted from the ULPA filter. There is a risk of desorption and contamination of the clean room, but there is a problem that awareness of this danger is low.
[0007]
This invention is made | formed in view of such a situation, and it aims at providing the desorption method of the organic compound which makes the organic compound adsorb | sucked to the filter remove | desorb from a filter, incorporating a filter in clean room equipment.
[0008]
[Means for Solving the Problems]
In order to achieve the above object , the present invention provides a method for desorbing an organic compound from a filter by desorbing an organic compound adsorbed on a filter of a plurality of fan filter units that blows clean air into a clean room of a clean room facility. Heated air from a heating source provided at the inlet portion of the fan filter unit is vented to a filter provided at the outlet portion of the fan filter, and the filter is passed through an upper space partitioned by a screen that vertically partitions the clean chamber. The air that has passed is exhausted to the outside.
[0009]
With the above configuration , heated air is passed through the filter that has adsorbed the organic compound, and the heated air is exhausted to the outside of the clean chamber, so that the organic compound is desorbed from the filter and discharged to the outside of the clean chamber. That is, when high-temperature air passes through the filter, the concentration of DOP and DBP, which are a kind of organic compounds in the clean room, increases, and the heated air is brought into contact with the glass fiber that is the base material of the ULPA filter. Thus, the organic compound can be desorbed and removed from the glass fiber. Thereby, since the organic compound adsorbed on the filter is removed, the life of the filter is improved. In addition to the above configuration, the clean room is partitioned by a screen, and the air is exhausted to the outside through the partitioned space.For example, the heated air is moved outside the clean room without using the work space of the clean room. Can be exhausted.
[0010]
The heated air that flows through the filter may be sent from the inside of the clean chamber to the outside through the FFU once-through air. If it does in this way, since heated air is ventilated through the filter from the inside of the clean room to the outside, the heated air containing the organic compound desorbed from the filter is discharged to the outside of the clean room.
[0011]
A plurality of fan filter units are installed on the ceiling surface of the clean room. The fan filter unit sucks and removes air from the back of the ceiling space and downflows to the clean room. In the clean room facility to be returned, a heater is provided in the air inlet portion of the fan filter unit so that air heated by the heater passes through a filter provided in the air outlet portion of the fan filter unit, and In the upper part of the chamber, a screen capable of partitioning the interior of the clean room up and down to form an upper space is disposed, and an exhaust pipe that communicates with the outside and can be opened and closed is provided in the upper space. Clean room equipment with organic compound desorption function.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for desorbing an organic compound and a clean room facility with a desorption function according to the present invention are described in detail below with reference to the accompanying drawings.
[0013]
FIG. 1 is a cross-sectional view showing the structure of a clean room facility to which an organic compound desorption method according to the present invention is applied.
[0014]
As shown in the figure, the clean room facility 10 has a clean room 12 in which a semiconductor production line (not shown) or the like is installed, and a plurality of FFUs (fan filter units) 14 are installed on the ceiling surface of the clean room 12. 14,... Are arranged. The FFU 14 sucks air in the ceiling space 16 and removes dust contained in the air, and then downflows the clean air to the clean chamber 12. The downflowed clean air is sucked into the underfloor chamber 20 from the grating floor 18 together with dust floating in the clean room 12. The air sucked into the underfloor chamber 20 is cooled and dried by a sensible heat treatment coil (not shown) and then returned to the ceiling space 16 through the return space 22. A part of the air in the underfloor chamber 20 is sent to an air conditioner (not shown) via the return air duct 24 and adjusted to a predetermined temperature and humidity, and then supplied to the ceiling space 16 from the air supply duct 26. I care. The air thus sent to the ceiling space 16 is purified again by the FFU 14 and downflowed into the clean room 12. Thereby, the clean chamber 12 is maintained at a high cleanliness and is adjusted to a substantially constant temperature and humidity (for example, 23 ° C., 45% RH).
[0015]
On the upper part of the cleaning chamber 12, a roll screen 28 is provided by winding a belt-like screen into a roll shape. As shown in FIG. 2, the roll screen 28 can be partitioned horizontally by pulling it horizontally.
[0016]
An exhaust pipe 30 is connected to the upper space 12 </ b> A of the clean chamber 12 partitioned by the roll screen 28. The opening of the exhaust pipe 30 is configured to be openable and closable, and the upper space 12 </ b> A communicates with the outside air through the exhaust pipe 30 by opening.
[0017]
FIG. 3 is a cross-sectional view showing the structure of the FFU 14.
[0018]
As shown in the figure, the FFU 14 includes a ULPA filter 34 and a fan 36 inside a casing 32. When the fan 36 is driven, air in the ceiling back space 16 is sucked from the air inlet 32 </ b> A at the upper part of the casing 32, and the air is downflowed toward the clean chamber 12 below the FFU 14. This air passes through the ULPA filter 34 disposed in the outlet 32 </ b> B of the casing 32, and dust is collected. As a result, clean air is flowed down from the FFU 14 toward the clean room 12.
[0019]
A heater 38 is installed at the air inlet 32 </ b> A of the casing 32. Therefore, the air sucked from the air inlet 32A can be heated by the heater 38. The temperature of the heated air can be arbitrarily set by the heater 38, and is set to, for example, a room temperature of a normal clean room or higher.
[0020]
Next, the operation of the clean room facility 10 configured as described above will be described.
[0021]
As shown in FIG. 1, during normal operation, the roll screen 28 is wound and the exhaust pipe 30 is closed. When the FFU 14 is driven in this state, clean air is blown from the FFU 14 and the clean chamber 12 is maintained at a high cleanliness. By performing normal operation in this manner, dust in the air is collected on the ULPA filter 34 of the FFU 14 and organic compounds in the air are gradually adsorbed. Since the adsorbed organic compound may be desorbed from the ULPA filter 34 and contaminate the clean chamber 12, it must be periodically removed.
[0022]
As shown in FIG. 2, the organic compound is desorbed by first pulling out the roll screen 28 to partition the clean chamber 12 up and down, and opening the exhaust pipe 30 to allow the upper space 12A to communicate with the outside air. Next, the fan 36 of the FFU 14 is driven and the heater 38 is turned on. Thereby, the air in the ceiling space 16 is sucked into the FFU 14, and the sucked air is heated by the heater 38. The heated air passes through the ULPA filter 34 of the FFU 14 and desorbs the organic compound adsorbed on the ULPA filter 34. The experimental results that serve as the basis will be described below.
[0023]
FIG. 4 shows the relationship between the air temperature supplied to the clean chamber 12 and the concentration of organic compounds (DOP, DBP) in the clean chamber 12. As shown in the figure, as the temperature of the air supplied to the clean chamber 12 increases, the concentration of the organic compound in the clean chamber 12 increases. In particular, when the temperature of the air is higher than the room temperature (about 23 ° C.) of a normal clean room, the concentration of the organic compound is remarkably increased. This is presumably because the organic compound adsorbed on the ULPA filter 34 was desorbed from the ULPA filter 34 due to the increase in the temperature of the air.
[0024]
Therefore, when heated air is passed through the ULPA filter 34 as in the present embodiment, the organic compound adsorbed on the ULPA filter 34 is desorbed from the ULPA filter 34. The heated air containing the desorbed organic compound is blown out into the upper space 12 </ b> A and then exhausted out of the clean room facility 10 through the exhaust pipe 30.
[0025]
As described above, according to the organic compound desorption method of the present embodiment, since the heated air heated by the heater 38 is passed through the ULPA filter 34 of the FFU 14, the organic compound adsorbed on the ULPA filter 34 is desorbed. Can be removed outside. Therefore, since the ULPA filter 34 is regenerated, the life of the ULPA filter 34 can be improved and the running cost can be reduced.
[0026]
In the present embodiment, the clean chamber 12 is partitioned by the roll screen 28 so that heated air containing an organic compound is not supplied to the lower space 12B. Therefore, it is possible to prevent high boiling point organic compounds such as DOP and DBP from adversely affecting the semiconductor production line (particularly the wafer) installed in the lower space 12B.
[0027]
Furthermore, this Embodiment can perform the removal | desorption operation | work of an organic compound, without removing the ULPA filter 34 from the ceiling surface of the clean room 12. FIG.
[0028]
The desorption operation of the organic compound is not only performed periodically, but may be performed, for example, when the air conditioner is stopped due to failure or inspection in summer. As a result, even if the temperature of the clean chamber 12 rises and the organic compound is desorbed from the ULPA filter 34, the air containing the organic compound is exhausted through the upper space 12A and the exhaust pipe 30, so that the lower space 12B is contaminated. Not. As shown in FIG. 5, when the blower 40 is disposed in the exhaust pipe 30, air containing an organic compound can be sucked by the blower 40. Therefore, even when the FFU 14 is stopped, the lower space 12B can be prevented from being contaminated.
[0029]
In the above-described embodiment, the clean room 12 is partitioned by the roll screen 28. However, the present invention is not limited to this, and the clean room 12 may be partitioned into the FFU 14 side and the lower space (that is, the work space) 12B side. Any device that can be used and that does not adversely affect the flow of clean air during normal operation may be used. For example, as shown in FIG. 6, an accordion screen 42 obtained by folding a belt-like screen in a zigzag manner may be used. The accordion screen 42 can be folded during normal operation.
[0030]
In the above-described embodiment, the air ventilated to the ULPA filter 34 is heated by the heater 38, but the heating means is not limited to this, and is heated by an external air conditioner (AHU) or the like. May be. In summer, high-temperature air at or above the normal clean room temperature may be formed by stopping the air conditioner.
[0031]
Further, in the above-described embodiment, the exhaust path for exhausting the heated air to the outside of the system is formed by the roll screen 28 and the exhaust pipe 30, but the present invention is not limited thereto. FIG. 7 shows an exhaust path formed by the suction device 44. The suction device 44 is a cart 50 that can travel on the grating floor, a suction device 46 that is supported on the cart 50 via a support column 48 and opened upward, and a suction device 46 that is mounted on the cart 50 and that is mounted on the cart 50. And a pump 56 for sucking air from the inside through a hose 54. The aspirator 46 is configured to surround the ULPA filter 34 of at least one FFU 14 when being brought into contact with the ceiling frame 52. Further, the discharge port of the pump 56 communicates with the outside of the system through a hose 55.
[0032]
In the suction device 44 configured as described above, when the pump 56 is driven, the inside of the suction device 46 becomes negative pressure, and the air in the ceiling space 16 is sucked into the suction device 46 through the ULPA filter 34. can do. Therefore, if the air is heated by the heater 38, the organic compound adsorbed on the ULPA filter 34 can be desorbed. Air containing an organic compound is exhausted from the inside of the aspirator 46 through the hose 54 to the outside of the system. The suction device 44 can sequentially remove and attach the plurality of ULPA filters 34 by moving the carriage 50 and changing the position of the suction device 46.
[0033]
Note that by providing a punching plate (not shown) or a current plate on the upper surface of the suction device 46, the suction air may be rectified and the ULPA filter 34 may be evenly attached and detached. Further, an elastic body such as rubber is provided at the upper end of the suction unit 46, and this elastic body is brought into contact with the ceiling frame 52 to prevent the heated air from leaking from the gap between the ceiling frame 52 and the suction unit 46. Good. Further, the support column 48 may be configured to be extendable and retracted. For example, when the support column 48 is contracted, the internal air of the support column 48 may be urged in the direction of being compressed and extended.
[0034]
FIG. 8 shows an embodiment in which heated air that is ventilated to the ULPA filter 34 is sent from the inside of the clean chamber 12 toward the ceiling space 16. In this embodiment, the detaching operation is performed by the movable detaching device 58.
[0035]
The detaching device 58 is provided inside the casing 60, a carriage 64 that can run on the grating floor 18, a casing 60 that is supported above the carriage 64 via a support 62 and that opens upward. The fan 66 and the heater 68 disposed in the upper opening of the casing 60 are configured. The lower opening 60A is uniformly formed on the lower surface of the casing 60 so as not to be biased. When the fan 66 is driven, air is sucked from the lower opening 60A and is sent upward. The air supplied upward is heated by the heater 68. As a result, the heated air heated to room temperature or higher in a normal clean room passes through the ULPA filter 34 of the FFU 14, so that the organic compound is desorbed from the ULPA filter 34. The heated air containing the organic compound is exhausted from the upper opening 32A of the casing 32 of the FFU 14 to the ceiling space 16. Therefore, it is possible to prevent the organic compound from contaminating the clean room 12. The desorption device 58 can desorb the ULPA filters 34 sequentially by moving the carriage 64 and changing the position of the casing 60.
[0036]
A driving source (not shown) such as a motor for driving the fan 66 may be mounted on the carriage 64. Further, by providing a punching plate (not shown) or a rectifying plate in the upper opening of the casing 60, the blown air may be rectified and the ULPA filter 34 may be evenly attached and detached. Further, an elastic body such as rubber may be provided at the upper end of the casing 60 and the elastic body may be brought into contact with the ceiling frame 52 to prevent the heated air from leaking from the gap between the ceiling frame 52 and the casing 60. Further, the support column 62 may be configured to be extendable and retractable. For example, when the support column 62 is contracted, the internal air of the support column 62 may be compressed and urged in the extending direction.
[0037]
In the above-described embodiment, the fan 36 of the FFU 14 may be rotated in the reverse direction of the normal operation instead of providing the fan 66 in the detaching device 58.
[0038]
【The invention's effect】
As described above , according to the present invention, heated air is ventilated to the filter that has adsorbed the organic compound, and the heated air is exhausted to the outside of the clean chamber, so that the organic compound is desorbed from the filter to the outside of the clean chamber. Discharged. Thereby, since the organic compound adsorbed on the filter is removed, the life of the filter is improved and the running cost is reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a clean room facility to which an organic compound desorption method according to the present invention is applied. FIG. 2 is a cross-sectional view of a clean room facility in which a clean room is partitioned by a roll screen. Fig. 4 is a diagram showing the relationship between air temperature and organic compound concentration ratio. Fig. 5 is a cross-sectional view of clean room equipment for forcibly exhausting heated air using a blower. Fig. 6 is a clean room showing a partitioning method different from Fig. 2. FIG. 7 is a side view showing a suction device that sucks and exhausts heated air. FIG. 8 is a side view showing an embodiment in which heated air is supplied from the inside of a clean room.
DESCRIPTION OF SYMBOLS 10 ... Clean room equipment, 12 ... Clean room, 14 ... FFU, 16 ... Ceiling space, 18 ... Grating floor, 28 ... Roll screen, 30 ... Exhaust pipe, 32 ... Casing, 34 ... ULPA filter, 36 ... Fan, 38 ... Heater, 40 ... blower, 42 ... accordion screen, 44 ... suction device, 46 ... suction device, 54 ... hose, 56 ... pump, 58 ... desorption device, 60 ... casing, 66 ... fan, 68 ... heater

Claims (2)

In the method for desorbing an organic compound that desorbs an organic compound adsorbed on a filter of a plurality of fan filter units that blows clean air to a clean room of a clean room facility, a heating source provided at an intake port portion of the fan filter unit The heated air is passed through a filter provided at the outlet of the fan filter, and the air that has passed through the filter is exhausted to the outside through an upper space partitioned by a screen that partitions the clean chamber up and down. Method for desorbing organic compounds. A plurality of fan filter units are installed on the ceiling surface of the clean room. The fan filter unit sucks and removes air from the back of the ceiling space and downflows to the clean room. In the clean room equipment to be returned, a heater is provided in the air inlet portion of the fan filter unit so that air heated by the heater passes through a filter provided in the air outlet portion of the fan filter unit. In the upper part of the chamber, a screen capable of forming an upper space by partitioning the inside of the clean chamber up and down is disposed, and an exhaust pipe that communicates with the outside and can be opened and closed is provided in the upper space. Clean room facilities with desorption function for organic compounds.

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