JPH0857224A - Circulation system for liquid to be treated - Google Patents

Abstract

PURPOSE: To provide a circulation system for liquid to be treated in which a specified capacity of a filter can be demonstrated. CONSTITUTION: A pulse absorber 60 is placed between a pump 4 and a filter 5, treatment liquid supplied from the pump 4, which is pulsing, is arranged so as not to be supplied directly to the filter 5 but supplied to the filter 5 after the pulse being absorbed by the pulse absorber 60, and the filtration pressure of the filter 5 is made nearly constant, so that the filter is constituted to demonstrate a specified filtration capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing liquid circulation system for circulating a processing liquid in a processing tank.

[0002]

2. Description of the Related Art Conventionally, various types of processing liquid circulation systems of this type are known. For example, as shown in FIG. 8, the processing tank 21 that stores the processing liquid 22 is provided with an overflow tank 23 around the processing tank 21, and the bottom of the overflow tank 23 is provided with a pump 24, a filter 25, and an in-line heater 26 for preventing the processing liquid temperature drop. Is connected to the bottom of the processing bath 21 to form a processing liquid circulation line 27. Therefore, the processing liquid overflowed into the overflow tank 23 enters the in-line heater 26 through the filter 25 after being supplied with a supply pressure by the pump 24, is heated to a predetermined temperature here, and is then supplied into the processing tank 21 again. It is supposed to be done. On the other hand, since the water contained in the treatment liquid in the treatment bath 21 and the overflow bath 23 evaporates from the treatment liquid 22, it is necessary to supply clean water to keep the concentration of the treatment liquid constant. For this reason, a clean water supply line 31, which is generally composed of a flow rate adjusting valve 28, a flow meter 29, and a clean water supply opening / closing valve 30 from a clean water tank (not shown), is a processing liquid circulation line between the inline heater 26 and the processing tank 21. It is connected to 27. Therefore, when the clean water is required, the open / close valve 30 is opened and the flow rate adjusting valve 28 adjusts the flow rate of the clean water to supply the clean water to the processing tank 21.

[0003]

However, in the structure described above, since the pulsating treatment liquid is directly supplied to the filter from the pump, the filtration pressure of the filter greatly varies due to the pulsating treatment liquid pressure. There is a problem that particles that are present in the treatment liquid and should be captured by the filter pass through without being captured by the filter, so that the ability of the predetermined filter cannot be exhibited.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a processing liquid circulation system capable of exerting the ability of a predetermined filter.

[0005]

In order to achieve the above object, the present invention has a pulse absorber interposed between a pump and a filter so that the processing liquid pulsatingly supplied from the pump is directly supplied to the filter. Instead, the treatment liquid after the pulsation is absorbed by the pulse absorber is supplied to the filter so that the filtration pressure of the filter becomes substantially constant and the predetermined filter performance is exhibited.

[0006] That is, the invention according to claim 1 is a treatment tank for containing a treatment liquid, a treatment liquid circulation line for discharging the treatment liquid from the treatment tank and supplying the treatment liquid into the treatment tank again, A pump provided in the circulation line for supplying the treatment liquid to the treatment tank, a filter arranged between the pump in the circulation line and the treatment tank for filtering the treatment liquid, and the filter in the circulation line. And a pulse absorber that is disposed between the pump and the filter and that absorbs the pulsation of the processing liquid from the pump. The invention according to claim 2 is the invention according to claim 1, further comprising an overflow tank disposed around the processing tank for storing a processing liquid overflowing from the processing tank, and the circulation line is provided with the overflow tank. It is arranged so as to be connected to the processing tank, and is configured to discharge the processing liquid from the overflow tank and supply the processing liquid again to the processing tank. The invention according to claim 3 is
In the invention of claim 2, it is configured to further include a clean water supply line connected to the overflow tank and supplying clean water. According to a fourth aspect of the present invention, in the invention of the second aspect, the processing liquid circulation line is configured to connect a bottom portion of the overflow tank and a bottom portion of the processing tank. The invention according to claim 5 is the invention according to claim 3, wherein the clean water supply line is connected to an upper portion of the overflow tank to supply clean water,
An in-line heater is arranged between the filter and the bottom of the overflow tank. Claim 6
In the invention according to any one of claims 1 to 5, the pulse absorber allows the pulsating treatment liquid to flow into the casing from the pump and extends by the pulsation of the treatment liquid to absorb the pulsation. The bellows that contracts by its own urging force to discharge the processing liquid is accommodated in an expandable manner, and the expansion of the bellows can be regulated by a regulating member. According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the regulating member of the pulse absorber is configured to be adjustable in and out of the casing to regulate the expansion width of the bellows. According to an eighth aspect of the present invention, in the sixth or seventh aspect of the invention, the inside of the casing of the pulse absorber and the outer periphery of the bellows are filled with compressed gas. According to a ninth aspect of the present invention, in the invention of the fifth aspect, the clean water supply line is connected to an inner surface of an upper peripheral wall of the overflow tank, and clean water is supplied into the overflow tank along the inner surface. To configure. The invention according to claim 10 is the invention according to any one of claims 6 to 8, wherein the treatment liquid is 150 to 170 ° C.
In the case of high temperature phosphoric acid, the casing and bellows of the pulse absorber are made of PTFE or PFA.

[0007]

According to the structure of the present invention, the pulse absorber is interposed between the pump and the filter so that the treatment liquid pulsatingly supplied from the pump is not directly supplied to the filter but the pulsating treatment is performed. The liquid is once allowed to flow into the pulse absorber to absorb the pulsation, and then the treatment liquid in which the pulsation is almost eliminated is supplied to the filter. Therefore,
The pressure of the processing liquid supplied to the filter becomes almost constant,
The filtration pressure of the filter becomes substantially constant, and particles that are present in the treatment liquid and that should be captured by the filter can be effectively captured by the filter, and a predetermined filter performance can be exhibited.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to FIG. In the treatment liquid circulation system according to the present embodiment, as shown in FIG.
It is a system for circulating a high temperature treatment liquid such as phosphoric acid at 170 ° C.
In this system, the processing tank 1 for containing the high-temperature processing liquid 2 is provided with an overflow tank 3 around it, and the bottom of the overflow tank 3 is a pump 4, a pulse absorber 60,
A high-temperature treatment liquid circulation line 7 is formed by being connected to the bottom of the treatment tank 1 via a filter 5 and a treatment liquid temperature-preventing in-line heater 6. That is, the present system relates to a nitride removing device equipped with a phosphoric acid circulation temperature control system. Therefore, the processing liquid overflowing into the overflow tank 3 enters the in-line heater 6 via the pulse absorber 60 and the filter 5 after the supply pressure is applied from the pump 4, so that the processing liquid does not drop below a predetermined temperature. After being heated, it is supplied again into the processing tank 1.

On the other hand, from the high temperature treatment liquid, the water contained in the treatment liquid in the treatment tank 1 and the overflow tank 3 evaporates and the concentration thereof changes, so that clean water is used to keep the concentration of the treatment liquid constant. The clean water is supplied through the clean water supply line 11. The clean water supply line 11 is generally composed of a clean water tank (not shown) including a flow rate adjusting valve 8, a flow meter 9, and a clean water supply opening / closing valve 10.
The tip on the supply side of 1 is connected to the upper portion of the overflow tank 3. The tip of the clean water supply line 11 is connected along the inner surface of the peripheral wall 3a of the overflow tank 3 so as to supply clean water into the overflow tank 3.
Therefore, when clean water is required, the on-off valve 10 is opened and the flow rate adjusting valve 8 is used to adjust the flow rate of the clean water while watching the flow meter 9 while the overflow tank 3 is made to follow the inner surface of the surrounding wall 3a. Supply clean water.

The pulse absorber 60 arranged between the pump 4 and the filter 5 absorbs the pulsation of the processing liquid discharged from the pump 4 and supplies the processing liquid in a state in which the pulsation is almost eliminated to the filter 5. It is for doing.

The pulse absorber 60 has a substantially cylindrical casing 61 made of a fluorine resin such as PTFE or PFA, and a bellows 62 made of a fluorine resin such as PTFE or PFA accommodated therein. A lid 64 made of a fluorine resin such as PTFE or PFA fixed to the lower surface is fixed to the casing 61 via an O-ring 71. The lid 64 has a casing 61 at the center thereof.
The inside of the casing 6 at the protruding portion 64d.
1 has a processing liquid inflow passage 64a penetrating substantially in the center thereof, and an auxiliary inflow passage 64c further penetrating therethrough is formed near the tip of the inflow passage 64a. on the other hand,
The processing liquid outflow passage 64b is formed in a portion of the lid 64 excluding the protruding portion 64d. The bellows 62 is arranged so as to cover the entire protruding portion 64d and locate the opening of the outflow passage 64b therein, and the open end of the bellows 62 is fixed to the lid 64 via the O-ring 71. Therefore,
In the bellows 62, the processing liquid flowing in from the inflow passage 64 a of the lid 64 is supplied to the tip portion of the bellows 62,
On the other hand, the pulsating pressure of the treatment liquid causes the bellows 62 to expand, while the treatment liquid in the bellows 62 flows out of the pulse absorber through the outflow passage 64b. The casing 61 has a cylindrical member 6 made of stainless steel, the outside of which is coated with a fluorine resin such as PTFE.
8 to reinforce and cover the casing 61
At the bottom of the, stainless steel bottom plate 66 coated with a fluorine resin such as PTFE is fixed and reinforced.
Further, the lid 64 is also covered and reinforced with a stainless steel lid plate 65 coated with a fluorine resin such as PTFE.

In the chamber 72 formed by the casing 61 and the lid 64, a compressed gas such as compressed air flows into the space outside the bellows 62 from the inflow port 69 and is filled and held. The bellows 62 expands and contracts due to the difference between the restoring force of the bellows 62 and the inflow pressure of the processing liquid, that is, the pulsating pressure. Also,
At the bottom of the casing 61, a restriction member 63 is arranged so as to face the bellows 62. The regulation member 63 is a disc-shaped flat surface portion 63 a that can come into contact with the bottom portion of the bellows 62.
And a male screw member 63 protruding in the center of the flat surface portion 63a.
b and. The external thread portion 63b is provided on the casing 61.
The amount of protrusion of the regulating member 63 into the casing can be adjusted by being screwed into the screw hole 61a in the central portion of the bottom of the bellows 62, and the tip flat portion of the bellows 62 can be the flat portion 63a of the regulating member 63. The expansion of the bellows 62 can be regulated by contacting with, and the expansion degree of the bellows 62 can be adjusted. Therefore, as a result, it is possible to prevent the bellows 62 from extending excessively. In addition,
Two liquid leakage sensors 67, 67 are arranged near the regulating member 63 on the bottom of the casing 61.
In the unlikely event that the processing liquid leaks into the casing 61 from the above, the sensors 67, 67 can detect it.

In the pulso absorber 60, the processing liquid that pulsates from the pump 4 through the inflow passage 64a is bellows 62.
Supplied within. The bellows 62 expands and contracts according to the restoring force of itself and the pressure difference between the bellows 62 and the compressed air filled in the casing 61 outside the bellows 62,
The expansion of the bellows 62 absorbs the pulsating pressure of the processing liquid. After the pulsating pressure is absorbed, the processing liquid is discharged to the outside of the pulso absorber 60 through the outflow passage 64b and supplied to the filter 5. On the other hand, the bellows 2 contracts by the urging force of the bellows itself and the action of compressed air until the next pulsating treatment liquid flows in after the treatment liquid accompanied by pulsation flows in and out, and the next treatment is performed. It is prepared for the inflow of liquid.

According to the above embodiment, the pulse absorber 60 is interposed between the pump 4 and the filter 5 so that the processing liquid pulsatingly supplied from the pump 4 is not directly supplied to the filter 5 but the pulsation is generated. The processing liquid which it has once flows into the pulse absorber 60, and after absorbing its pulsation, the processing liquid in the state where the pulsation is almost eliminated is supplied to the filter 5. Therefore, the pressure of the treatment liquid supplied to the filter 5 becomes substantially constant, the filtration pressure of the filter 5 becomes substantially constant, and the particles existing in the treatment liquid and to be captured by the filter 5 are effectively captured by the filter 5. Therefore, it is possible to exert a predetermined filter ability.

Since the tip of the clean water supply line 11 on the supply side is connected to the upper portion of the overflow tank 3,
When clean water is supplied into the overflow tank 3, the gas contained in the clean water evaporates when it dissolves in the high temperature treatment liquid of the overflow tank 3 and is discharged to above the overflow tank 3 or the like. Does not dissolve in the processing liquid. Therefore, even if the processing solution containing almost no gas is supplied from the overflow tank 3 to the bottom of the processing tank 1 through the high-temperature processing solution circulation line 7, and the processing solution in which clean water is dissolved is supplied to the bottom. No gas is generated, therefore, wafer cracking does not occur due to the disappearance of pure water bumping in the processing tank, wafer rotation is prevented, and scratches on the wafer surface due to rotation are prevented, and there is no adverse effect on the wafer. . In addition, if the tip of the clean water supply line 11 is supplied along the inner surface of the peripheral wall 3a of the overflow tank 3, the clean water will be generated as compared with the case where the clean water is poured toward the liquid surface of the treatment liquid. It smoothly dissolves in the processing liquid and less gas dissolves when supplying clean water. Further, since the tip of the clean water supply line 11 is connected to the upper part of the overflow tank 3, it is not necessary to change the structure of the overflow tank 3 at the time of piping or to change the design of other devices. It will be.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

For example, the treatment liquid may be a treatment liquid at any temperature such as a room temperature one. Also, clean water supply line 11
It is advantageous to connect to the upper portion of the overflow tank 3 because the above effect can be obtained, but when it is not necessary to obtain such an effect, it should be connected to an arbitrary portion instead of the upper portion. May be. When the clean water supply line 11 is connected to the upper portion of the overflow tank 3, the tip of the clean water supply line 11 on the supply side is supplied along the wall of the overflow tank 3 on the processing tank side instead of the peripheral wall 3a. Alternatively, a dedicated wall may be provided separately for supply. Further, the liquid may be supplied by dropping it directly on the liquid surface of the overflow tank 3, or may be supplied in the form of a shower on the liquid surface.

Further, in the above-mentioned embodiment, as shown in FIG. 4, when the temperature of the treatment liquid exceeds a predetermined value and the heating by the in-line heater 6 is unnecessary, the treatment tank is directly passed through the filter 5 without going through the in-line heater 6. A heater bypass valve 15 for allowing the processing liquid to flow in
The inline heater 6 may be bypassed by opening 5.

In the above embodiment, the overflow tank 3 and the clean water supply line 11 may be provided as needed. That is, when these are unnecessary, as shown in FIG.
The processing tank 1, the pump 4, the pulse absorber 60, the filter 5, and the processing liquid circulation line 7 that connects these in order.
May be configured as follows. In this case, the circulation line 7 discharges the treatment liquid from the upper side or the intermediate portion side of the treatment tank 1 and supplies the treatment liquid from the bottom portion of the treatment tank 1 via the pump 4, the pulse absorber 60 and the filter 5. There is.

The connection relationship between the processing tank 1 and the circulation line 7 is not limited to that shown in FIGS. 1 to 5, and for example, as shown in FIG. 6, the processing liquid is circulated from the peripheral portion of the bottom of the processing tank 1. Alternatively, the processing liquid may be discharged through the line 7 and the processing liquid may be supplied again from the central portion of the bottom. Also, as shown in FIG.
The processing liquid is discharged from the upper part or the middle part of the processing tank 1 by the circulation line 7, bent in an L-shape from the upper part of the processing tank 1 to the bottom part, and then, on the surface of the supply pipe 7a lying on the bottom part of the processing tank 1. A large number of supply holes may be formed to supply the processing liquid into the processing tank 1 through the supply holes. This supply pipe 7
Depending on the size of the processing tank 1, a may be branched into, for example, a Y shape, an E shape, or the like, and may be arranged at the bottom of the processing tank, and the processing liquid may be supplied from a large number of supply holes.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a processing liquid circulation system according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional side view of the pulse absorber according to the above embodiment of the present invention.

3 is a plan view of the pulse absorber shown in FIG. 2. FIG.

FIG. 4 is a schematic explanatory diagram of a processing liquid circulation system according to another embodiment of the present invention.

FIG. 5 is a schematic explanatory diagram of a processing liquid circulation system according to still another embodiment of the present invention.

FIG. 6 is a schematic explanatory diagram of a main part of a processing liquid circulation system according to still another embodiment of the present invention.

FIG. 7 is a schematic explanatory view of a main part of a processing liquid circulation system according to still another embodiment of the present invention.

FIG. 8 is a schematic explanatory diagram of a conventional high temperature treatment liquid circulation system.

[Explanation of symbols]

1 ... Processing tank, 2 ... Processing liquid, 3 ... Overflow tank, 3a
... peripheral wall, 4 ... pump, 5 ... filter, 6 ... in-line heater, 7 ... high temperature processing liquid circulation line, 8 ... flow rate regulating valve,
9 ... Flow meter, 10 ... Open / close valve, 11 ... Clean water supply line,
12 ... Carrier case, 13 ... Wafer, 15 ... Heater bypass valve, 60 ... Pulse absorber, 61 ... Casing, 62 ... Bellows, 63 ... Regulation member, 64 ... Lid,
65 ... Lid plate, 66 ... Bottom plate, 67 ... Liquid leak sensor, 68 ...
Cylindrical member, 69 ... Compressed air inlet, 71 ... O-ring, 7
2 ... room.

Claims (10)

[Claims] 1. A processing tank (1) for containing a processing liquid (2).
And a processing liquid circulation line (7) for discharging the processing liquid from the processing tank (1) and again supplying the processing liquid into the processing tank (1).
A pump (4) provided in the circulation line (7) for supplying a treatment liquid to the treatment tank (1), the pump (4) in the circulation line (7) and the treatment tank (1) A filter (5) disposed between the pump (4) and the filter (5) in the circulation line (7), the filter (5) being disposed between the pump (4) and the filter (5). Absorber for absorbing pulsation of treatment liquid (60)
And a treatment liquid circulation system. 2. The method further comprises an overflow tank (3) which is arranged around the processing tank (1) and stores a processing liquid overflowing from the processing tank (1), and the circulation line (7) includes the overflow tank. Tank (3)
And the processing tank (1) is connected so that the processing solution is discharged from the overflow tank (3) and the processing solution is supplied again to the processing tank (1).
The processing liquid circulation system according to 1. 3. The treatment liquid circulation system according to claim 2, further comprising a clean water supply line (11) connected to the overflow tank (3) and supplying clean water. 4. The processing liquid circulation system according to claim 2, wherein the processing liquid circulation line (7) connects the bottom of the overflow tank (3) and the bottom of the processing tank (1). 5. The clean water supply line (11) is connected to the upper part of the overflow tank (3) to supply clean water, and between the filter (5) and the bottom part of the overflow tank (3). The processing liquid circulation system according to claim 3, wherein an in-line heater (6) is arranged in the chamber. 6. The pulse absorber (60) allows a pulsating treatment liquid to flow from the pump (4) into the casing (61) and extends due to the pulsation of the treatment liquid to absorb the pulsation, while the pulse absorber (60) itself The bellows (62) that contracts by an urging force and discharges the treatment liquid is accommodated in an expandable manner, and the extension of the bellows (62) can be regulated by a regulating member (63). The processing liquid circulation system according to 1. 7. The restricting member (63) of the pulse absorber (60) is adjustable in and out of the casing (61) to restrict the extension width of the bellows (62). The processing liquid circulation system according to 1. 8. The processing liquid circulation system according to claim 6, wherein a compressed gas is filled in the casing (61) of the pulse absorber (60) and around the outside of the bellows (62). . 9. The clean water supply line (11) is connected to an inner surface of an upper peripheral wall (3a) of the overflow tank (3), and clean water is supplied into the overflow tank along the inner surface. The processing liquid circulation system according to claim 5, wherein 10. The casing (61) and the bellows (62) of the pulse absorber (60) are made of PTFE when the treatment liquid is hot phosphoric acid at 150 to 170 ° C.
Alternatively, the processing liquid circulation system according to any one of claims 6 to 8, which is composed of PFA.